Progress 11/01/21 to 10/31/22
Outputs
Target Audience:The target audience are the wood composites industry, automotive industry, prepreg manufacturers, research community, and the students. We reached these audience through two published articles on resin transfer molded wood strand panels and wood strand prepregs and compression molded laminates. We also presented the research findings to BASF, Dieffenbacher, and LP Corp. Results have been also presented to natural fiber processing facilities to generate interest in develpoing other natural fiber based panels using resin transfer molding. Formology, Oregon based company, is working with us currently in developing such panels for architectural applications. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?One postdoc has been working on the project while engaging a few undergraduate students in the project. Postdoc was being mentored by the PI. Students have been learning how to produce wood strands, fabricate wood strand prepregs and laminates, and test and evaluate the prepregs and laminates. How have the results been disseminated to communities of interest?Two journal articles have been published. Have been engaging suppliers to automotive industries, such as BASF and Dieffenbacher, to inform them about biobased prepregs that can replace synthetic prepregs for certain applications. We have also been engaging natural fiber processors to inform them about extending the concept to other natural fibers to produce biobased prepregs and panels for a variety of applications, inlcuding automotive and building construction. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
To build on the work done on wood strand prepregs and laminates using these prepregs, we started exploring the limits of forming these wood strand prepregs by bending them during compression molding them into profiled laminates. We started exploring bending them about one axis using V-bending tests. In addition, to form them with biaxial bending, we designed dome-shaped mold with certain geometry and had it manufactured by WSU's machine shop to conduct experimental work on forming limits. While we have been doing this work, we also engaged industrial clients to get them interested in working with us to eventually conduct trial runs at their facilities to mold wood strand prepregs into biobased laminates with varying profiles using industrial molds. We have been also preparing to present these results at future conferences and publishing as well.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Gartner, B., V. Yadama, and L.V. Smith. 2022. Resin transfer molding of wood strand composite panels. Forests, 13(2), 278, https://doi.org/10.3390/f13020278.
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Mohammadabadi, M., V. Yadama, and L.V. Smith. 2022. Wood-based prepreg for composite laminates. Wood and Fiber Science, 54(2):122-133, https://doi.org/10.22382/wfs-2022-13.
|
Progress 11/01/15 to 10/31/22
Outputs
Target Audience:The target audience reached were wood composite manufacturers, researchers, industry leaders in the Pacific Northwest, and the students. Efforts to reach this target audience included: 1. Technical presentations at 18th SPE Automotive Composites Conference & Exhibition (Novi, MI) and Timber 2019 (London, UK). The audience included manufacturers, end users of wood composite panels, researchers, and students from different countries in North America, South America, Europe, and Asia. 2. Personal meetings with industry to discuss the potential of resin transfer molding of wood strand and natural fiber mats into interior and exterior panels for automotive applications and decorative architectural panels for residential and commercial buildings. These companies included Dieffenbacher, Ford, Hyundai, Formology and clients of Formology, and Louisianna Pacific Corp. 3. Showcased samples of resin transfer molded wood strand composite panels at CleanTech Innovation Showcase 2019 in Seattle, WA. 4. Provided experiential learning experience to NSF Summer REU students. Students were taught and trained in RTM of composite panels. With this experience, the REU students produced and evaluated composite panels of wood strands and natural fibers. Changes/Problems:Major problems have been the delay due to pandemic and recruitment issues, which have resulted in the delay in achieving the deliverables. Certain issues in mold design and delay in receiving the completely designed set-up have also affected the progress. Machine breakdowns have also been experienced in the last year, further adding to the problems. Therefore, some of the final deliverables are yet to be completed, which have been outlined previously and have been planned to be completed and disseminated within the next few months. A second postdoc, Dr Avishek Chanda, has been hired last year who has worked on designing the dome mold and is working on wrapping up the project as soon as possible. Successful completion of final task will make sure all the project goals are achieved. What opportunities for training and professional development has the project provided?Two graduate students completed their master's theses on this topic and are currently employed. Several undergraduate students were inducted and provided real-time learning experience to create strand feedstocks, fabricate wood strand preforms and to resin transfer mold composite panels. The students were also introduced to thermoforming processes and testing and evaluation of wood strands, prepregs, and laminates and analyze the results. Both undergraduate and graduate students learned the critical aspects to consider regarding the lignocellulosic materials' structure and bonding behavior, and how to develop an understanding of forming these lignocellulosic materials into composite panels. These students were trained by three Postdocs who were recruited during the project period. Postdocs were also mentored by the PI to extend the research to other natural fibers, overcome hurdles faced, disseminate results, and mentor undergraduate and graduate students. How have the results been disseminated to communities of interest?Results have been disseminated periodically at various international and domestic conferences and showcases. Timber 2019 and CleanTech Innovation Showcase 2019 were the initial two platforms where the studies from the project were presented to academic and industry leaders. We also demonstrated the technology to a local company in Oregon who has ever since been interested in resin transfer molding natural fiber composites and we have been working with them on running USDA SBIR and WSU's Commercialization Gap Funding (CGF) projects. Two Masters theses have been completed during the project duration. The prestigious Natural Fibernamics Award was also won in 2021 at the 5th International Conference on Natural Fibers, Materials of the Future. The results have also been disseminated successfully to two resin companies, Hexion and Arkema, resulting in the development of long-lasting relationships, which still continues in other projects. The Timber2019 conference paper was further extended to a research article that was published in Forests in 2022. Advances in research leading to the development of a wood strand prepreg, analogous to synthetic fiber prepregs, have also been published in 2022 as another research article in Wood and Fiber Science. Recently completed work, at the end of the project period, will also be published in the near future. Work on wood strand prepreg was presented to BASF and Dieffenbacher as a biobased option for molding interior automotive auotmotive parts. Both have shown interest in conducting trial runs to explore the efficacy of these prepregs in molding into automotive panels. What do you plan to do during the next reporting period to accomplish the goals?This is the final report for the project. However, there is still more work being completed as part of the project to establish the viability of the claim that molded parts of complex geometries can be formed using the established process. The work will be carried out over the next few months to establish the ideal parameters for laminating symmetric and quasi-isotropic flat panels, forming consistent stable structures with large curvatures in the fabricated V-shaped, dome-shaped and waffle-shaped molds. The possibility of testing the process in industrial molds still is viable depending on the industry's suitability. An abstract has been accepted to present the results at a conference in April organized by the Society of Plastics Engineers (SPE). A manuscript by 2023 summer will be the final dissemination of the project outcomes in the form of a refereed jouran article.
Impacts
What was accomplished under these goals?
The following were accomplished during the project duration: 1. The entire study has been focused on reducing steps and optimizing the process of producing molded wood strand composite panels for automotive applications. In the initial stages, the preform was fabricated using a binder in the form of PVAc or polyethylene before performing the resin transfer molding operation using a combination of vacuum, injection pressure and transverse compression force to achieve finished surfaces and high fiber volume fraction. However, discussions with industries proved this technique to be time consuming, economically intensive (additional manufacturing cost) and resulting in reduced production speed and unwanted changes in the production process. Therefore, through further studies and research, a vitrimer polymer was selected for resin transfer molding of wood strands as it behaves like a thermoset in liquid form and as a thermoplastic once cured. Elium®, produced by Arkema, was the resin that was selected. This resin's viscosity being only 100 cps is ideal for resin transfer molding. Once cured, the resin behaves as a thermoplastic and the fabricated thin wood-strand composite prepregs can then be layered and molded under heat and pressure into flat panels or complex multi-axially formed structures. 2. Through several trials, using vacuum assisted resin transfer molding (VARTM) and hot press, a method was conceived that has the potential to be a cost-effective one for fabricating molded parts for automotive applications. The procedure involves 2 clear steps: i) fabrication of thin wood strand reinforced prepregs using Elium and vacuum assisted resin transfer molding in a vacuum bag, and b) using the prepregs as feedstock to engineer a laminate that can be compression molded in a hot press similar to what is done with carbon fiber reinforced prepregs. Repetitive trials helped the team to gain experience in using Elium®, which was initially engineered for synthetic fibers, such as glass fiber, to be effectively used to produce prepregs form natural fibers, such as wood strands, using VARTM and without any external pressure. Studies with the aid of scanning electron microscopy (SEM) proved that the lumen structures were completely filled with the thermoplastic resin that resulted in 38% and 124% higher Young's Modulus and tensile strength of the resin infused wood-strand prepregs compared to those before impregnation. These prepregs do not have to be stored in cold storage similar to carbon fiber prepregs. These prepregs were then used to develop flat laminates while idealizing the molding parameters. A hydraulic hot-press was used to establish the required parameters as 356°F and 120 psi. The target thickness was kept at 0.2", resulting in the use of 12 layers of prepregs with each prepreg being about 0.018". Due to pressure and reduction in thickness from consolidation, 12 layers were established to provide 0.2" panels. A comparison of the results with established products from the literature proved that the thermoformed laminates are significantly stronger and stiffer both in bending and tension when compared to standard compression resin transfer molded (CRTM) wood strand panels using epoxy and hot-pressed (HP) wood-strand panels using phenol formaldehyde resin. The laminates were also significantly resistant to moisture uptake while having superior dimensional stability, again compared to the CRTM and HP panels. One of the biggest advantages of using Elium® is its recyclability, which was also studied. The tested prepreg and laminate specimens were chopped up using a knife mill, at Composite Materials and Engineering Center, WSU, and fed through an extruder to generate pellets that were then injection molded to fabricate composite specimens. 3. In order to achieve complex multi-axially formed structures, a systematic multi-step approach was deviced. Three steps of i) single axis bending, ii) double-axis bending and iii) multi-axis bending, were decided to be carried out. Single axial bending in the form of V-bending was carried out as the first step to establish the formability hypothesis of the wood strand prepregs. Through repetitive iterations and trial runs, the time to acquire the desired temperature of 356°F at the central layer was established to be about 20 mins in the mold set-up used. The process of thickness control was utilized, and the samples were held at the desired thickness of 0.25" for 19 mins under constant heat and pressure. The pressure was further held till the temperature of the mold reduced to 180°F, before unloading the sample. Bend radius of ¾" was established to be ideal as lower radii resulted in buckling and tensile fracture in the laminates. With single curvature bending established, the next step of double curvature was targeted. A dome shaped structure was determined ideal for the study, which also replicates many automotive and aerospace parts, one such example being the nose of an aircraft. The mold needed to be designed and set-up for performing the studies. After various iterations and design changes through discussions with the Engineering Shop at WSU, the dome shaped mold was designed and fabricated in-house. The mold was fabricated in a way that enabled it to be installed on a Universal Testing Machine, giving more control on the pressure, speed and process. A cooling system was also introduced to ensure fast cooling of the mold and reduced processing time. Initial studies have shown the promise to achieve stable structures with higher number of laminates and cross-orientation that will enable the prepregs to withstand the shear thinning and generated tensile stresses. The study is still going on and will be completed within the next couple of months. Once a stable structure is achieved, the third step will be carried out on an in-house waffle mold, which is already present at the center.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Mohammadabadi, M., V. Yadama, and L.V. Smith. 2022. Wood-based prepreg for composite laminates. Wood and Fiber Science, 54(2):122-133, https://doi.org/10.22382/wfs-2022-13.
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Gartner, B., V. Yadama, and L.V. Smith. 2022. Resin transfer molding of wood strand composite panels. Forests, 13(2), 278, https://doi.org/10.3390/f13020278
|
Progress 11/01/20 to 10/31/21
Outputs
Target Audience:The target audience we reached out to is the automotive industry, oriented strandboard manufacturers, and chemical company. In specific, we reached out to Ford Motor Company, Louisinanna Pacific Corp, and BASF. Ford Motor Company is interested in natural fiber reinforced thermoplastic composites for automotive applications. BASF is interested in natural fiber-based prepregs that can be laminated and molded into 3D parts for automotive applications. We presented our work conducted in this project to LP's Director of Siding Technology. He is interested in finding out more about the product and its applications for building construction. They will be also interested in producing wood-strand prepregs if it is economically viable and if there is a market demand. The work on wood prepreg was also submitted for Natural Fibrenamics Award 2021 at the 5th International Conference on Natural Fibers that was held virtually. Our work won the award and was recognized for its innovativeness. Changes/Problems:Major problem we faced was delay in carrying out the tasks due to slowing down of the work because of COVID-19 and the Postdoc leaving to take up another job. However, work is being performed by the PI and the student workers and a new Postdoc has been recruited to complete the remaining tasks. What opportunities for training and professional development has the project provided?Project enabled supporting the following personnel during 2020-2021 reporting period: Supported two undergraduate student research assistants, Spencer Lowder and Thaw Naing, working on developing advanced wood strand composite materials for automotive applications. Spencer Lowder completed his undergraduate degree in Mechanical Engineering, where as Thaw Naing is pursuing his undergraduate degrees in Civil and Environmental Engineering. Another undergraduate student, Domenica Gachet, also worked on this project and was supported by other funds. Supported a Postdoc, Mostafa Mohammadabadi, working on research and development of wood strand prepregs and determining their formability for automotive applications. How have the results been disseminated to communities of interest?Results were disseminated via preparing and submiting a manuscript to publish in a peer-reviewed journal. Results were also presented at the 5th Inernational Conference on Natural Fibers -- Materials of the Future to compete for the Natural Fibremanics Award 2021 and won the award. This award is given to the most innovative product developed from natural fibers. Work was also presented to Louisianna Pacific's Director of Siding Technology. What do you plan to do during the next reporting period to accomplish the goals?To achieve the objectives articulated in the funded proposal, we have lot more to accomplish to demonstrate the feasibility of consistently producing molded automotive parts with wood strand-thermoplastic prepregs. We are currently testing and evaluating shape stability, thickness variation, and density variation of v-bend specimens of two laminate thicknesses and at bend angles of 30, 45, and 90 degrees. Also, we are in the process of fabricating multiple large wood strand prepregs for molding into an automotive part at BASF. We are seeking assistance from our company partners, Ford and BASF, to demonstrate the technology we are developing. Our plan in 2021-2022 is to run some trial runs using the molds from BASF to manufacture wood strand-thermoplastic molded car parts. Following are the tasks for the next reporting period to accomplish the goals: 1. Complete shape stability and dimensional stability evaluation under different environmental conditions (12% MC and wet environment) 2. Fabricate at least 25-30 wood strand prepregs for molding at BASF. 3. Demonstrate compression molding with prepregs at BASF. 4. Prepare and publish a paper on shape and dimensional stability and the ability to mold into laminates for automotive applications. 5. Disseminate research findings at conferences and complete the final report for USDA NIFA.
Impacts
What was accomplished under these goals?
Since we have partially reopened the labs in 2020, a lot of progress has been made to understand how to consistently fabricate a thermoplastic wood strand prepreg and are getting ready to conduct a detailed study to produce a molded part using these prepregs. Next few sections will outline what has been accomplished during this past reporting period regarding wood-strand prepregs that can be used similar to carbon fiber prepregs to manufacture molded laminated composite panels (this was a significant work achieved during the 2020-2021 NCE period that was granted). Wood-Based Prepreg Innovation: A natural fiber prepreg using wood strands has been developed with a thermoplastic resin for use as feedstock for fabricating laminated composite materials, flat or profiled, by compression molding for a variety of applications including automotive interior and exterior panels. Motivation: 1) Need for a biobased prepreg, similar to carbon fiber prepreg, for downstream manufacturing of compression molded panels for value-added markets, such as automotive and aerospace applications, with an ability to recycle at the end of their service life. 2) Find higher value applications for underutilized and low-value small diameter timber (SDT) from fast-growing plantations or hazardous fuel treatments. 3) Contribute to sustainable management of our forests and improve forest health. Approach: Form wood strand mat into complex geometries using VARTM and compression molding technologies for potential applications in the automotive industry. Significant Results: Lumens of wood strands were completely filled with the thermoplastic resin resulting in 38% and 124% higher Young's modulus and strength of the wood prepregs compared to wood strands prior to being infused with resin. Thin wood strand reinforced thermoplastic prepregs that can be used to compression mold into laminates that are significantly stronger and stiffer in bending and tension than compression resin transfer molded wood strand panel using epoxy resin (CRTM-E) and hot-pressed wood strand panel with phenol formaldehyde (HP-PF) resin. Prepreg laminates are resistant to moisture uptake and are dimensionally very stable as reflected in the water absorption and thickness swelling results. Outcome: Thin and flexible thermoplastic wood-strand prepregs that can be laminated by compression molding into panels that are flat or profiled with complex three-dimensional cross-sections with the ability to recycle the products at the end of their service life. These prepregs do not have to be stalked in cold storage. Impacts: Use of renewable materials for value-added products Contributing to sustainable forest management practices Fits within the circular economy model New opportunities and applications for wood-based composites with wood strands from SDT
Publications
- Type:
Journal Articles
Status:
Other
Year Published:
2022
Citation:
Mohammadabadi, M., V. Yadama, and L.V. Smith. Wood Prepreg for Composite Laminates. In preparation for Wood & Fiber Science by SWST
- Type:
Other
Status:
Published
Year Published:
2021
Citation:
Mohammadabadi M., V. Yadama, L.V. Smith. 2021. Wood-based prepreg. Submitted for Natural Fibrenamics Award 2021, 5th International Conference on Natural Fibers, Materials of the Future, May 17-19, 2021, Virtual Conference. Won the award!
|
Progress 11/01/19 to 10/31/20
Outputs
Target Audience:During this period, we reached out to three key target audience: 1. Automotive industries through Center for Bioplastics and Biocomposites that Washington State University is an integral part of. As we are developing these composites for automotive applications, we wanted to recieve their feedback on our process. They like the fact that we are using renewable fibers, wood strands. However, the message was clear from the automotive industry that any composite materials for use in cars should be processed using thermoplastic polymers as a matrix. This enables them to recycle the material. Therefore, in 2019, we decided to pivot and see if we can use a thermoplastic resin instead of a thermoset that enables post-processing of cured flat panels at a later stage into molded parts. 2. Thermoplastic industry, specifically Arkema, is the other company we reached out to. Typical thermoplastics, such as polypropylene or polyethylene, do not bond with wood strand well and also do not penetrate the wood structure. Coincidentally, in 2019, PIs learnt about a new resin that was just developed by Arkema called Elium. Elium is a liquid thermoplastic resin of low viscosity and allows us to use the same manufacturing technique, RTM, as with thermoset resins to fabricate composite panels. We contacted Arkema in summer of 2019 and they have provided us the resin. As Elium was designed for synthetic fibers, such as glass fiber, we have to learn from experience how to use it effectively with natural fibers, such as wood strands. 3. Based on resin transfer molding of wood strands research conducted during the first three years of the project, we started exploring resin transfer molding other natural fibers that are waste products of plants processing materials such as seeds and treenuts. We were approached by Formology, an Oregon company, as they were interested in decorative architectural panels. We had done some preliminary work on producing small-size panels using RTM with sunflower hulls and hazelnut shells. Changes/Problems:As reported previously, a major change incorporated was shifting to a thermoplastic matrix from a thermoset matrix. This has opened up creative oppotunities to produce wood-strand composite products for automotive applications, especially since the automotive industry is interested in use of thermoplastic matrices and the ability to recycle composite materials. Another factor that really affected the research was COVID-19. Trial runs and experiments were delayed as a result of not being able to get to the labs. Although we have been conducting research in the labs since July 2020, complete access and flexibility is still limited due to COVID-19 rules and regulations implemented by the state and the university. What opportunities for training and professional development has the project provided?Two Postdocs were partially supported on the grant to overcome the barriers and determine solutions to achieve the project objectives. Two undergraduates were supported on the project to assist with manufacturing of panels and testing strands and laminates. They were trained by the Postdocs to conduct resin transfer molding and test and evaluate properties of the prepregs and laminates. How have the results been disseminated to communities of interest?Yes, results were dissminated to targetted automotive industries and panel producers interested in natural fiber composite panels for decorative architectural panels. Results were also presented on resin transfer molded wood strand composites at an international conference in Europe to disseminate to the interested wood composite industry and researchers. What do you plan to do during the next reporting period to accomplish the goals?Since we have partially reopened the labs in June of 2020, a lot of progress has been made to understand how to consistently fabricate a thermoplastic wood strand prepreg and are getting ready to conduct a detailed study to produce a molded part using these prepregs. To achieve the objectives articulated in the funded proposal, we have lot more to accomplish to demonstrate the feasibility of consistently producing molded automotive parts with wood strand-thermoplastic prepregs. We are seeking assistance from our company partners, Ford and Hyundai, to demonstrate the technology we are developing. Our plan early 2021 is to run some trial runs using their molds to manufacture wood strand-thermoplastic molded car part. We plan to achieve the following tasks during the next reporting period: Determine right temperatures and pressures to laminate the wood-strand prepregs into thick laminates and test and evaluate the laminates. Demonstrate moldability of flat laminates into complex shapes and evaluate the molded parts for their properties. Work with automotive industry partners to perform trial runs using their molds to manufacture wood strand-thermoplastic molded car part they recommend. Publish and present our research findings.
Impacts
What was accomplished under these goals?
Since the last reporting period, a significant progress was made in the project. As was conveyed in previous years' annual reports, PIs have shown through a master's thesis that wood strand composite panels with thermoset resins, such a vinyl ester and epoxy, can be manufactured using resin transfer molding. We have demonstrated that flat panels with excellent mechanical properties and minimum moisture uptake and dimensional changes can be fabricated, however there are some barriers. Wood strand preforms have to be compressed under large pressures to consolidate them to desired target thickness and density during the resin infusion process (what we referred to as a compression-RTM process). Furthermore, these flat panels cannot be molded into shapes as the resins are thermosets. Therefore, to mold them into shapes for automotive applications, we have to heat and soften the preforms, shape them, and then infuse with resin. Wood composite manufacturers would consider this an energy intensive process that is not economically viable. Therefore, in 2019, we decided to pivot and see if we can use a thermoplastic resin instead of a thermoset that enables post-processing of cured flat panels at a later stage into molded parts. Typical thermoplastics, such as polypropylene or polyethylene, do not bond with wood strand well and also do not penetrate the wood structure. Coincidentally, in 2019, PIs learnt about a new resin that was just developed by Arkema called Elium. Elium is a liquid thermoplastic resin of low viscosity and allows us to use the same manufacturing techniques as with thermoset resins to fabricate composite panels. We contacted Arkema in summer of 2019 and they have provided us the resin. As Elium was designed for synthetic fibers, such as glass fiber, we have to learn from experience how to use it effectively with natural fibers, such as wood strands. After several months of trial, we were able to produce wood strand prepregs using Elium and VARTM without any added pressures. These prepregs can be subsequently be laminated and molded using compression molding process into automotive parts. Just when we were getting ready to conduct a series of experiments to study the influence of processing parameters on wood strand prepreg performance and establish process-property relationships, our work came to a halt because of COVID-19. Since we have partially reopened the labs in June of 2020, a lot of progress has been made to understand how to consistently fabricate a thermoplastic wood strand prepreg and are getting ready to conduct a detailed study to produce a molded part using these prepregs. Following sections will provide additional details regarding fabricating wood strand preforms and prepregs using Elium. Wood prepregs that are 0.018-inch thick were produced using wood strands and Elium resin. To fabricate wood prepregs, paper strips sprayed with Super 77 Multipurpose Adhesive by 3M were used to stitch strands together into a mat. Then, the strand mat was trimmed to an approximate length of 5.5 inches and were placed end to end and joined again using paper strips to form a large one-strand thick preform. We will explore other means of stitching strands together in the future, but the method developed for now seems to work well as a proof-of-concept. Wood-strand preforms were then used to make a wood-strand prepreg using vacuum assisted resin transfer molding (VARTM). The preform was laid on a flat aluminum plate and covered by peel ply to allow removal of preform (after curing of the resin) from other layers used during the VARTM process. Flow media was placed on top of the peel ply to facilitate flow of resin during its infusion using vacuum. Different lengths of flow media coveage relative to preform length in the direction of resin flow were tried (1/4, ½, ¾, and entire length of the preform). Finally, ¾ of the preform length was covered by the flow media as it yielded most favorable results in terms of the injection time, resin coverage, and resin consumption. Spiral tubes were used at the resin entry and exit ports to evacuate air prior to resin injection and to subsequently inject the resin into the preform. Before injecting the resin, air from the preform was evacuated by applying vacuum for 15 minutes. Following the evacuation of air, resin was injected into the preform and was allowed to cure at room temperature. Even though Elium needs only about three hours to cure, the resinated preform was left under vacuum overnight to cure the resin and was removed the day after and post-cured in an oven. Final result is a thin and flexible wood prepreg with thickness of 0.018 inches. This preform can be formed into different shapes and molded again using compression molding. Since the resin is a thermoplastic resin, it can also be recycled by grinding up the material and reprocessing. Tensile coupons were prepared from these prepregs to evaluate their strength and stiffness. Average ultimate tensile strength was approximately 15,000psi with a coefficient of variation (COV) of 20% and average Young's modulus was around 1.97 million psi with a COV of 14%. These are are excellent mechanical properties and should result in high-performance laminated composite panels. Lamination of these prepregs and their performance evaluation is ongoing currently. To prove to ourselves that a composite panel produced using Elium can be molded, we formed a flat wood strand panel into a complex shape using a matched-die mold in a hot-pressed using Elium. The resulting 3-D panel was stable and strong. These accomplishments during this year give us the confidence that we can achieve our goals in the next year of producing thermoplastic wood-strand panels and demonstrating that they can be molded into complex shapes.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Gartner, B., Yang, W., Yadama, V., and Smith, L.V. 2019. Resin transfer molding of wood strand composite panels. Timber 2019, London, UK, July 3-4.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2019
Citation:
Jani, Hasan Rafsan. 2019. Strategies to fabricate natural fiber composite panels using VARTM. MS Thesis, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA.
|
Progress 11/01/18 to 10/31/19
Outputs
Target Audience:The target audience reached were wood composite manufacturers, researchers, industry leaders in the Pacific Northwest, and students. Efforts to reach this target audience included: 1. Technical presentation at Timber 2019 in London, UK. Audience included manufacturers, end users of wood composite panels, researchers, and students from different countries in Europe. 2. Personal meetings with industry to discuss the potential of resin transfer molding of wood strand and natural fiber mats into architectural panels. 3. Showcased samples of resin transfer molded wood strand composite panels at CleanTech Innovation Showcase 2019 in Seattle, WA. 4. Provided experiential learning experience to NSF Summer REU student. Student was taught and trained in RTM of composie panels. With this experience, the REU student produced and evaluated hybrid composite panels of basalt and natural fiber. Changes/Problems:A major change is in recruiting of a Postdoc instead of a PhD student, as we proposed in the original proposal, since we could not find a student with suitable qualifications. What opportunities for training and professional development has the project provided?Undergraduate students were provided experiential learning experience to fabricate wood strand preforms and to resin transfer mold compostie panels. These students were trained by a Postdoc who was recruited during this reporting period. How have the results been disseminated to communities of interest?Results were disseminated at an international conference (Timber 2019) to wood composite manufacturers, end users, and researchers. Additionally, our research was showcased as an ongoing work at CleanTech Innovation Showcase 2019 in Seattle, WA to industry leaders and others in the Pacific Northwest. We also demonstrated the technology to a local company in Oregon who is interested in resin transfer molding natural fiber composite panels for architectural panels. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, our plan is to demonstrate the use of Elium resin in manufacturing thin wood strand reinforced prepregs similar to carbon fiber prepregs. Subsequent to forming these wood strand prepregs, we will implement compression molding to prove that molded parts can be manufactured for automotive applications. Compression molded panels will be evaluated for their performance. This 2-step process of manufacturing molded parts using Elium resin and results of the performance evaluation will be presented at the Annual SPE Automotive Composites Conference and Exhibition in Novi, MI. We also plan to submit a manuscript that is under preparation based on the original proposed method of producing molded wood strand composite panels using thermoset resin. We will prepare another paper based on the work that will be done in the coming months using the new method of wood strand prepregs using a vitrimer polymer (Elium) which can be subequently molded into composite products.
Impacts
What was accomplished under these goals?
Following were the accomplishments during this reporting period: 1. We have been researching as to how to reduce the steps to produce a molded wood strand composite product for automotive applications. Our steps at present include fabricating a preform with a binder such as polyethylene or PVAc followed by resin transfer molding using a combination of vacuum and injection pressure to infuse the preform with resin. We realized that it is necessary to apply transverse compression on the mold to achieve good surfaces and high fiber volume fraction (resulting from consolidation of wood strands and squeezing out the excess resin). We realized from talking to the automotive industry (members of NSF IUCRC with WSU as one of the collaborating institutions) that these steps are time consuming and would add to the manufacturing cost. Production speeds have to be faster and any additional steps, such as adding binder and preparing a preform for downstream consolidation under pressure, would not be suitable and economical for producing interior panels for an automobile. Therefore, we need to find better solutions. 2. A major accomplishment during this reporting period was finding a resin that is a vitrimer polymer that behaves like a thermoset, but when cured would become a thermoplastic. Elium, produced by Arkema, is a new development in this area of vitrimer polymers. Viscosity of Elium is around 100 cP which is ideal for resin transfer molding. However, after the resin is cured with a catalyst, it behaves like a thermoplastic. Using Elium, we can resin transfer mold wood strand composites which can be subsequently molded under heat and pressure as the resin would behave like a thermoplastic. 3. After several trials using different techniques, we have conceived a method that we think would be cost effective in producing molded parts for automotive applications. Our procedure would involve two clear steps: a) fabrication of thin wood strand reinforced pre-pregs using Elium and vacuum assisted resin transfer molding in a vacuum bag, and b) using pre-pregs as feedstock to engineer a laminate that can be compression molded in a hot press similar to what is done with carbon fiber reinforced prepregs. During the next reporting period, we will validate our procedure, evaluate performance of prepregs and flat laminates that are compression molded, and mold a profiled part to demonstrate use of prepregs and compression molding to form 3D molded parts.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Gartner, B., Yang, W., Yadama, V., and Smith, L.V. 2019. Resin transfer molding of wood strand composite panels. Timber 2019, London, UK, July 3-4.
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Progress 11/01/17 to 10/31/18
Outputs
Target Audience:The target audience included the forest products and automotive industry and their vendors. Results of the study were presented at the 18th Annual SPE Automotive Composites Conference & Exhibition. Research findings were also shared with Dr. Alper Kiziltas in the bio-based research group at Ford Motor Company. We have been preparing a manuscript based on the first thesis that was completed in the Fall semester of 2017 to be published in Composites Part B, which will help to disseminate the research findings to the sceintific community interested in wood composites and composites for automotive applications. There has been a delay in submitting the publication as we wanted to conduct additional analysis and extensively rewrite the paper. Changes/Problems:The PhD student (recruited to carryout the research after the Master's student) did not perform to our expectations and was moved out of the project. This has delayed the progress, but we hope to recruit another PhD student or a PostDoc to accomplish our goals in the upcoming year. What opportunities for training and professional development has the project provided?A graduate student has been mentored and trained to resin transfer mold natural fiber and wood strand compostie panels usiing all metal mold and a vacuum bag. How have the results been disseminated to communities of interest?Results were disseminated primarily through personal interactions with forest products and automotive industries through the Center for Bioplastics and Biocomposites Center at WSU and by participating as a speaker at the 18th-SPE Automotive Composites Conference & Exhibition in Novi, MI. What do you plan to do during the next reporting period to accomplish the goals?Due to underpeformance of the recruited PhD student to carry on the work completed by the MS student, we were not able to accomplish significant amount of work. In the coming year we plan to accomplish: 1. Recruiting of a new student or Post Doc to carryon the research. 2. Model and experimentally study the resin flow through wood strand preforms with two- and three-dimensional curavtures using VARTM. 3. Conduct high-resolution microscale x-ray computed tomography of wood strand preforms to understand the porous structure. 4. Publish the work completed by the Master's student.
Impacts
What was accomplished under these goals?
We have accomplished the following: 1. An understanding of the effects of binder type and binder quantity in fabricating wood-strand preforms for subsequent resin transfer molding. One percent LDPE is effective in producing 1ft by 1ft preforms for resin transfer molding with vinyl acetate and epoxy resins. 2. Compression RTM (CRTM) panels generally produce panels with higher performance and greater fiber volume fractions (~35-40%). 3. We have determined permeability constant using volumetric interpretation of Darcy's law, but realized that we need to model resin flow to better understand placement of resin injection ports and vacuum ports. 4. Initial benchmark values of ponderosa pine wood strand composite panels using VARTM and CRTM processes. They include flexure strength and modulus, tension strength and modulus, Izon impact energy, and water absorption and thickness swell. 5. Initial understanding of resin and wood strand interaction through infusion of resin through a few strands and the use of microscopy. This is critical in determining if the voids within wood strands influences the resin flow or is it all about the porosity between the strands.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Gartner, B. Dec 2017. Effects of preform architecture and processing parameters on the production of wood strand reinforced resin transfer molded composite panels. MS Thesis, Washington State University, Pullman, WA.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Gartner, B., Yang, W., Yadama, V., and Smith, L. Resin Transfer Molding (RTM) of Bio-Based Composite Panels, 18th Annual SPE Automotive Composites Conference & Exhibition, Sept 5-7, 2018, Novi, MI
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Progress 11/01/16 to 10/31/17
Outputs
Target Audience:The target audience in 2016-17 included mainly the undergraduate and graduate students working with PI on the project and majoring in Mechanical Engineering and Material Science and Engineering Program at Washington State University. Another set of audience included faculty in Materials and Mechanical Engineering Dept. working on biobased adhesives. The intent was to use a biobased diluent in lieu of styrene, but unfortunately large volumes of the required bio-based product could not be obtained. We also reached out to resin manufacturers, specifically Hexion and Vinythai, to obtain epoxy-based resins that are less volatile and/or bio-based to some degree. Hexion has agreed to send us their epoxy resin for molding. We will be trying out this resin in the coming year. We also communicated our work on wood strand molding products using RTM and VARTM to start-up companies interested in manufacturing natural fiber composite panels. Oregon-based start-up company collaborated with us in applying for funds to resin transfer mold natural fiber panel products. An undergraduate student was trained in resin transfer and vacuum-assisted resin transfer molding and has been helping us with natural fiber molding. Changes/Problems:A major change based on the what was reported last year in the progress report is regarding the use of bio-based resins. Working with faculty developing bio-based resins at WSU, we discovered that much of theresearch is still in the initial stages and is not capable of providing the required quantities of resin to conduct resin flow analysis and production of large panels forperformance evaluation. So, we will contiue to explore commercially available RTM/VARTM resins as indicated in the funded proposal and not pursue bio-based resins that are still being developed. What opportunities for training and professional development has the project provided?Training activities have been provided through the development of composite production skills, such as hot pressing, liquid composite molding, and mold development. Training activities have also been provided through the testing of the mechanical properties, moisture properties, permeability values, and quantification of resin and binder properties. Training activities also include one-on-one work with other graduate students researching similar topics to help learn new skills and assist in the advancement of the aforementioned objectives. Undergraduate student was trained to carryout future work on molding natural fiber composite panels. A PhD student, recruited to continue the initial work byBen Gartner (MS student), has been trained in the procedures of fabricating a preform as well as molding a wood strand composite panel. How have the results been disseminated to communities of interest?Results have been communicated to resin producers to acquire less-volatile resins for future work during the project duration. Hexion has agreed to supply epoxy-based resins that are relatively safer to handle and do not off-gas. Two startup companies have been introduced to the work we have been conducting. One of these companies that is Oregon-based has sponsored an undergraduate student to carry out resin transfer molding of natural fibers using the processes that we have developed for wood-strand panels. In collaboration with this company, we have applied for an internal grant within WSU for carrying out research on resin infusion and molding of natural fiber panels. A publication is under preparation to be submitted to Composites Part A. What do you plan to do during the next reporting period to accomplish the goals?A PhD student has been recruited to continue and advance the research based on the work conducted by the MS student that resulted in a MS thesis. During the next reporting period, the study will focus on understanding how to model resin flow through wood-strand preform and how processing variables will influence the resin flow. This is necessary to scale up the process to produce larger panels, as well as panels with curvature. Work will initially concentrate on literature review, identifying ideal modeling platform, and simulating resin flow and comparing the results with experimental data gathered by Ben Gartner during the last year on smaller-size panels.
Impacts
What was accomplished under these goals?
Progress on the first objective (resin flow analysis through wood strand preforms) has focused on studying the volumetric permeability of wood strand preforms in order to create a statistical model describing the influence of preform and processing variables on resin flow and to facilitate the routine production of the optimal preform architecture for resin transfer molding. In addition to developing a volumetric method for estimating permeability, the methodology for producing preforms bound with thermoplastic polyethylene has been devised. The use of a polyethylene binder produces a loosely bound preform with sufficient permeability to inject resin and sufficient stiffness and stability to be handled and machined to the proper size. In the future, apolyethylene encapsulatedpreform could also providean opportunity to thermoform more complex preforms from more easily produced flat preforms. Once this facet of the project is fully understood, two- and three-dimensional curvature will be incorporated and studied. Standard operating procedures have been developed for the production of RTM and CRTM composite panels using the internal pressure of the mold to indicate complete infusion of the resin. The composite panels produced using RTM were used to study the differences in permeability and mechanical properties of panels manufactured using preforms of varying binder content and type. A statistical analysis of the panel's physical properties, mechanical properties, and permeability was performed to select an idealcombination of preform binder content and type. After molding through comporession RTM (CRTM), the mechanical properties and dimensional stability of the panels were compared to other natural fiber and synthetic fiber composites. Progress includes the design and development of a mold for the study of one-dimensional and volumetric permeability of synthetic and bio-based resins through wood strand preforms. The knowledge accumulated through the design and production of this mold will expedite the design of more complex future molds. From the results of this phase of the study it has been determined that a maximum of 1 wt% LDPE binder is sufficient to sufficiently bind wood strands into a stable and usable preform that has necessarypermeability for use with RTM. No significant benefits in permeability or mechanical properties are derived from the use of higher LDPE content or the use of HDPE. The use of a volumetric interpretation of Darcy's law circumvents any issues associated with the resin flow not being visible through the acrylic mold surface as it flows through the center of the preform or along the aluminum mold surface. When compared with other natural fiber composites, RTM wood strand composites generally exhibit superior mechanical and moisture absorption properties.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Gartner, B. 2017. Effects of preform architecture and processing parameters on the production of wood strand reinforced resin transfer molded composite panels. MS in Materials Science and Engineering, Washington State University, Pullman, WA.
- Type:
Journal Articles
Status:
Other
Year Published:
2017
Citation:
Gartner, B., Yadama, V., and Smith, L. Effects of preform architecture and processing parameters on the production of wood strand reinforced resin transfer molded composite panels. In preparation to be submitted to Composites Part A.
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Progress 11/01/15 to 10/31/16
Outputs
Target Audience:The target audience for this phase of the project include undergraduate and graduate students studying materials science and engineering and civil engineering. The target audience also includes the research community working on the development of value added wood-based composite products, wood composites manufacturers, and the automotive industry. Outreach will be directed towards the research community and wood industries through national and international conferences. Industry members to be targeted include those in the automotive industry, such as Ford. Undergraduate and graduate students were trained to use the available equipment in the research lab to produce wood strand preforms and produce composite panels using vacuum assisted resin transfer molding. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training activities have been provided through the development of composite production skills, such as hot pressing, liquid composite molding, and mold development. Training activities also include one-on-one work with other graduate students researching similar topics to help learn new skills and assist in the advancement of the aforementioned objectives. Professional development opportunities include invitations to wood industry conferences, computer modeling seminars, and materials science and engineering seminars. How have the results been disseminated to communities of interest?A conversation has been initiated with automotive industry partners in order to gain feedback and guidance. Ford and Hyundai have been informed about the project and requested for periodic guidance. As a result of this initial contact, Ford has provided PIs with their headliner and door trim substrate specifications. In addition to surveying the published literature, guidance will also be solicited from these industry partners in regards to appropriately selecting the manufacturing parameters for resin flow analysis. Automobile manufacturers' feedback and material specs will serve as metrics for measuring the success of the project. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, significant progress on the study of wood strand preform permeability and the utilization of environmentally friendly resins will be made. The study of one-dimensional permeability of synthetic and bio-based resins through a wood strand preform will be performed in order to optimize the preform architecture and processing parameters. Cure kinetics and viscosity analysis of neat resins and resins with catalysts will be studied. The results of these tests will allow for a comparison of petroleum-based, styrene crosslinked resins with fully bio-based resins and crosslinking agents in liquid molded wood strand composites.
Impacts
What was accomplished under these goals?
This research is an attempt to introduce renewable materials into current automobile industry to contribute towards sustainable practices. Wood strands represent a very attractive, low cost material as they are derived from low quality, fast growing timber which can be obtained from forest thinning operations, hazardous fuel treatments, and/or fast-growing plantations. The use of wood strands in interior automobile panels will contribute to displacing petroleum-based polymers. Use of wood in durable products would also capture and sequester carbon. Their low density and high specific properties can produce an interior panel meeting the performance requirements, but lowering the overall vehical wegith which can also reduce vehicle emissions. These features make wood strand-based composites an attractive addition to automobile manufacturers growing repertoire of tools to reduce the cost and increase fuel efficiency of their fleet of vehicles. Progress on the first objective (resin flow analysis through wood strand preforms)has focused on studying the one-dimensional permeability of wood strand preforms in order to create a statistical model describing the influence of preform and processing variables on resin flow and to facilitate the routine production of the optimal preform architecture for resin transfer molding. Once this facet of the project is fully understood, two- and three-dimensional curvature will be incorporated and studied.Progress includes the design and development of a mold for the study of one-dimensional permeability of synthetic and bio-based resins through wood strand preforms. The knowledge accumulated through the design and production of this mold will expedite the design of more complex future molds. Second task of the first objective includesutilization of alternative, environmentally friendly resins for use in resin transfer molded wood strand composite panels. A study of the cure kinetics of bio-based resins and the elimination of styrene will be performed to demonstrate the efficacy of environmentally friendly resins.
Publications
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