Source: UNIV OF WISCONSIN submitted to NRP
BIOBASED, FULLY SOIL-BIODEGRADABLE MULCH FILMS PREPARED FROM BIOMASS FOR SUSTAINABLE BIOECONOMY
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1029678
Grant No.
2023-68016-38933
Cumulative Award Amt.
$1,000,000.00
Proposal No.
2022-08949
Multistate No.
(N/A)
Project Start Date
Jan 1, 2023
Project End Date
Dec 31, 2025
Grant Year
2023
Program Code
[A1414]- Bioenergy Feedstock Logistics Program
Recipient Organization
UNIV OF WISCONSIN
21 N PARK ST STE 6401
MADISON,WI 53715-1218
Performing Department
(N/A)
Non Technical Summary
Conventional and organic crop growers depend on plastic mulches for multiple benefits such as weed suppression, soil temperature modification, soil moisture retention, and improved crop yield and quality. However, traditional plastic mulches are not biodegradable in soil.plastic mulch removal and disposal are laborious and costly.As a result, most growers resort to landfilling or stockpiling used plastic mulch waste or even burning their plastic mulch waste, which not only costs the growers for disposal but also becomes a grand environmental problem. Therefore, developing biobased and soil-biodegradable mulches is of great interest and importance to agriculture and the environment.This project is to develop 100% biobased and fully soil-biodegradable mulch films from low-cost and renewable biomass (e.g., poplar wood, forest residues, sawdust) through a facile process of dissolution and regeneration. An environmentally friendly and inexpensive solvent, a concentrated aqueous solution of inorganic salt (e.g., LiBr, CaBr2), will be used for biomass dissolution and regeneration. The salt can be easily recycled and reused. The resultant films are composed of cellulose, lignin, and hemicelluloses and thereby are fully biobased and intrinsically soil-biodegradable. Specifically, we will develop and optimize the fabrication of the mulch films from woody biomass via a process of dissolution and regeneration and ensure the resultant films have sufficient mechanical strength and other properties to meet mulch application needs while being biobased and fully soil-biodegradable. The films will be carefully characterized and evaluated to investigate their structure-performance relationship, chemical and structural properties, mechanical strength, optical properties, and soil-biodegradability related to mulch performance. Techno-economic analysis (TEA) and life cycle assessment (LCA) will be conducted to quantify the economic feasibility and potential environmental impact of the proposed films for mulch applications compared with conventional polyethylene films. We will develop and deliver project information that summarizes relevant findings and evaluate the impact of technology transfer through a strategic extension program among target stakeholder groups and the public. Successful completion of the project will provide a fully biobased and soil-biodegradable mulch film to replace plastic ones, which will benefit agriculture, the environment, and the bioeconomy.
Animal Health Component
50%
Research Effort Categories
Basic
25%
Applied
50%
Developmental
25%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
51106802020100%
Knowledge Area
511 - New and Improved Non-Food Products and Processes;

Subject Of Investigation
0680 - Other products of the forest;

Field Of Science
2020 - Engineering;
Goals / Objectives
The goal of this integrated research-extension project is to produce biobased and fully soil-biodegradable lignocellulosic films (LCFs) with satisfactory mulching performance to replace petroleum-derived plastic mulches used in horticultural crop production. Through the proposed extension activities, the research findings and technologies on soil-biodegradable mulches (BDMs) will be effectively delivered to stakeholders and the public. To achieve the goal, we will pursue the following four supportingobjectives.Develop and optimize the fabrication process of LCFs from woody biomass via a process of dissolution and regeneration. LCFs will be prepared from abundant, low-cost, and renewable woody biomass (e.g., poplar wood, forest residues, sawdust) through a facile process of dissolution and regeneration. An environmentally friendly and inexpensive solvent, molten salt hydrate (MSH)--a concentrated aqueous solution of inorganic salt (e.g., LiBr, CaBr2), will be used for biomass dissolution and regeneration. The salt can be easily recycled and reused. The LCFs are composed of cellulose, lignin, and hemicelluloses and thereby are fully biobased and intrinsically soil-biodegradable. The resultant LCFs should have satisfactory properties to meet mulch application needs while being biobased and fully soil-biodegradable.Characterize and evaluate the developed LCFs to investigate their structure-performance relationship, chemical and structural properties, mechanical strength, optical properties, and soil-biodegradability related to mulch performance.TEA and LCA to quantify the economic feasibility and potential environmental impact of the proposed LCFs for mulch application; understand potential economic and environmental benefits/risks of LCFs compared with conventional polyethylene (PE) films.Develop and deliver project information that summarizes relevant findings and evaluate the impact of technology transfer through strategic extension programming among target stakeholder groups and the public.
Project Methods
This project includes the following four tasks (objectives):Task 1:Fabrication of lignocellulosic mulch films (LCFs) from woody biomassThis task aims to fabricate LCFs from woody biomass with satisfactory mechanical strength to meet mulching performance while being fully soil-biodegradable to replace plastic mulches. The major activities include establishing a process of cellulose dissolution and regeneration to fabricate LCFs from woody biomass, optimizing the process conditions to fabricate the LCFs with a homogeneous structure and satisfactory strength, understanding the changes to cell wall components (cellulose, lignin, and hemicelluloses) during the film fabrication, establishing process mass balance, and functionalizing the films with satisfactory dry and wet strength, opacity, and soil-biodegradability to meet the mulching performance requirements.Expected results: (1) The proposed project will develop a technology to fabricate strong, stretchable, black, yet fully soil-biodegradable LCFs from woody biomass as mulch films. (2) The proposed research would generate knowledge and a fundamental understanding of the dissolution and regeneration of woody biomass. (3) The results obtained under this objective would provide strategies to improve the properties and performance of LCFs.Milestones: (1) established LCFs fabrication method, (2) process chemistry and mass balance, and (3) functionalized LCFs as mulch films.Indicators of success: (1) detailed conditions and procedure for fabricating LCFs, presentations and publications; (2) wood-to-film yield, changes to cell wall components, and publications and presentations; (3) sufficient mechanical strength, weather resistance, black, and soil-biodegrading rate, and publications.Task 2: Characterization and evaluation of LCFsThis task aims to investigate the structure-property relation of the LCFs and characterize and evaluate the LCFs for mulching application. Proposed activities include understanding the interactions between cellulose, hemicellulose, and lignin in LCFs and their roles and contributions to the film properties and performance and characterizing the mechanical properties (strength), structural morphology, light transmittance and absorbance, wet strength and stability, weather resistance, and biodegradability of the LCFs.Expected results: (1) fundamental understanding of the inter-molecule interactions among cellulose, lignin, and hemicelluloses in the proposed LCFs, which offers crucial insight into the underlying mechanisms that govern the mechanical performance of the LCFs; (2) The dependence of key performing indices (tensile strength, elongation, weather resistance, etc.) on the micro-/nano-scale material structural features of the LCFs; and (3) Biodegradability performances of LCFs.Milestones:properties of LCFs, mulch performance of LCFsIndicators of success:characterization of mechanical, morphological, and optical properties; hydrophobicity, wet strength, and permeability; Weather resistance (changes in mass, composition, and mechanical properties) and biodegradability rate; presentations and publications; webinars; extension publications.Task 3: TEA and LCA of the LCFsThis task aims to develop LCA and TEA models for assessing the potential environmental impact and economic competitiveness of the proposed soil-biodegradable LCFs compared with polyethylene films currently used in the US agriculture sector.Expected results: The LCA will estimate environmental impacts per kg and per m2of LCFs. We will include impact indicators related to climate change, human health, resource depletion, and ecosystems. The TEA results will be $ of kg and $ of m2of LCFs fabricated. We will also estimate the environmental impacts and costs of LCFs to cover 1 unit area of land (e.g., 1 ha) and compare with previous literature that used the same functional unit for PE films.Milestones:TEA and LCA of LCFsIndicators of success:Economic feasibility and environmental impact of LCFs; reports; presentations; publicationsTask 4: Dissemination of technology and knowledge (Extension)This task is to disseminate project information to stakeholders given the importance of translating project findings to the industry for application and gathering their feedback through evaluation. Information dissemination is also important for extension professionals, so they are knowledgeable about available information resources and trained to pass on information to growers and other professionals. Information dissemination will share new project information with our target stakeholder groups including the agricultural plastics and film industry, the pulp and paper industry, feedstock manufacturers, university researchers, extension personnel, and growers. The impact of technology transfer and stakeholder perspectives on LCFs will also be evaluated through surveys, interviews, and focus groups.Expected results: Expanding our extension programs to include LCFs will broaden our sphere of information sharing and impact leading to changes in knowledge. In turn, this will lead to future development and commercialization of biobased, soil-biodegradable LCFs for agriculture and other applications in the medium- and long-term. Our data-sharing platform will be integral catalysis for these changes in knowledge and practice. Additionally, we anticipate results from our evaluations will identify key concerns stakeholders have with LCFs that we can address through our dynamic outreach approach and future research. Evaluations will also reveal the key strengths of LCFs and opportunities that create paths for commercialization and adoption by the industry. Impact assessments will also capture our ability to extend information effectively and allow for necessary modifications.Milestones:Stage 1, Introducing LCFs; Stage 2, Sharing new information about LCFs; Stage 3, Continuing information disseminationIndicators of success:White paper; website/social media posters; trade journal and newsletter articles; cyberinfrastructures; reach out to stakeholders; Webinars; online data sharing; PPT presentations; conference presentation; journal articles; online surveys and interviews of stakeholders; stakeholders' feedback; a report to National Organic Standards Board.

Progress 01/01/24 to 12/31/24

Outputs
Target Audience: Graduate and undergraduate students through formal classroom instruction (BSE 460-Biorefining at UW-Madison). Graduate students participated in the research activities of this project. The general public, farmers, mulch film producers, etc., through the website, newsletter, presentations, etc. (AMI Agricultural Film conference, Lynden Ag Show/Small Fruit Conference) Peer researchers through seminars and presentations at conferences (e.g., AIChE meeting, International Society of Industrial Ecology conference, and American Society for Horticultural Science conference). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?UW-Madison: One postdoc and three graduate students were involved in this project at the University of Wisconsin-Madison. Through this project, the postdoc and students studied the knowledge of biomass, and molten salt hydrate, and learned the skills and techniques for analysis and characterization of biomass. They were also trained in literature research, experiment design, data analysis, technical communication, and manuscript preparation for publication. The postdoc and students learned how to use the instruments/equipment for preparation, characterization, and soil biodegradation of lignocellulosic films, including universal test machine, TGA, contact angle, AFM, SEM, XRD, rheometer, etc. One graduate student attended and presentedat the 7thInternational Conference on Nanogenerators and Piezotronics (NGPT 2024), May 19 - 23, 2024, in Madison, WI. The postdoc and two students attended and presented at the 2024 AIChE meeting. WSU:One graduate student is involved in the project at Washington State University. The student has learned about soil-biodegradable mulch feedstocks and the unique attributes of LCF, experimental design and fundamentals of data analysis, technical communication to academic and non-academic audiences, and manuscript preparation. UMD:One graduate student is involved in the project at the University of Maryland, College Park. The student has learned about the mechanical testing of lignocellulosic films and how to extract key mechanical properties of the films from such testing. The student is also trained in literature study, technical communication, and technical writing. Yale:One postdoc was involved in this project at Yale. He was offered opportunities to serve as a mentor to graduate students in Yao's industrial ecology and life cycle assessment courses. The plastic life cycle assessment literature collected was incorporated into Yao's life cycle assessment class, which had30 + students/year, predominately professional master's students. How have the results been disseminated to communities of interest? The ideas, results, and findings of the project were shared with students in the course "Biorefining: Energy and Products from Renewable Resources" offered annually by PI (Dr. Pan). This made more students aware of the technology developed in this project and its impact on the area. Part of the outcomes and findings from this project were presented at the46thSymposium on Biomaterials, Fuels, and Chemicals (SBFC), April 28 - May 1, 2024, Westin Alexandria of Old Town, Alexandria, VA. Part of the outcomes and findings from this project were presented with two oral presentations at the 2024 AIChE Annual Meeting to share with peers. Information about LCF was shared in a newsletter article titled, "What is lignocellulose film?", published inSustainable Mulch Management. The article has a readership of 259 individuals worldwide involved in soil-biodegradable mulch research, outreach, and manufacturing. LCF film was introduced at various academic and industry events including conferences and a field day in 2024. The target audience reached included specialty crop growers, mulch film recyclers, film extruders, mulch manufacturers, academics, crop consultants/extension agents, and other industry stakeholders. We estimate approximately 250 people were educated on LCF films at these events. What do you plan to do during the next reporting period to accomplish the goals? Functionalize LCFs to meet the requirements of mulch films, such as improving elongation and wet stability. Furthermore, evaluate their performance as mulch films compared to commercial alternatives. Upgrade an existing wet spinning machine and integrate several custom-designed components to enable efficient and consistent LCF production. The updated lab-scale system will support a continuous production process, replicating industrial operations on a smaller scale to validate the feasibility of future scale-up. Research the dependence of various processes and raw materials on the mechanical properties and microstructure of the films. Set up an appropriate standard method and condition to test the films, for example, find an appropriate humidity condition to run the test. Conduct field tests of the LCFs to evaluate their performance as mulch films in comparison with commercial mulch films. Update the project webpage quarterly with new information. Distribute emerging project information via mulch-specific social media channels, specifically Mulch_Matters Instagram, LinkedIn, and podcast accounts. Share new information via webinars with emphasis on comparisons between PE mulch and LCF. Webinar attendees will be evaluated for their perspectives on the LCFs, including knowledge change and bridges and barriers to use (where applicable) via Qualtrics online surveys, focus group meetings, or one-on-one interviews using an interview template. Author another newsletter article in the Sustainable Mulch Management newsletter, as well as leverage emerging project information and publish in trade journals, and update PowerPoint slides available on the project webpage. Disseminate information at academic and trade conferences. Begin impact assessment after webinar and conference presentations via Qualtrics surveys to assess barriers and bridges to using LCF. Continue training postdoc and graduate students through this project. Publish peer-reviewed journal articles based on the results and findings from this project. Based on the preliminary results of the life cycle assessment, propose improvement strategies, e.g., material recycling and green energy sources. Advance conventional methods of life cycle assessment to include the biodegradation performance of LCF, comparing the environmental impacts of various end-of-life options between LCF and conventional plastic mulches.

Impacts
What was accomplished under these goals? This project is to produce fully soil-biodegradable lignocellulosic films (LCFs) from wood chips.The LCFs are expected to have satisfactory mulching performance to replace petroleum-derived plastic mulches used in horticultural crop production. Through the proposed extension activities, the research findings and technologies on soil-biodegradable mulches (BDMs) will be effectively delivered to stakeholders and the public. During this reporting period (from 2024-01-01 to 2024-12-31), the following activities/experiments were conducted/completed. Cellulose (wood powder) dissolution in a concentrated salt (LiBr or CaBr2) is the most critical operation to fabricate LCFs as mulch film through the proposed approach of dissolution and regeneration. Therefore, we carefully studied the dissolution process of cellulose in calcium bromide solution and lithium bromide solution, respectively. It was found that the cellulose dissolution is dependent on salt concentration, temperature, pH, cellulose loading, cellulose structure, and other factors. Optimal conditions have been determined for cellulose dissolution in both LiBr and CaBr2 solutions. It was also demonstrated that LCFs can be prepared from cellulose, wood pulp, and wood powder via dissolution and regeneration in the salt solutions. These results and findings are included in two manuscripts. One has been published (https://doi.org/10.1016/j.carpta.2024.100522) and another is in preparation. We established a protocol to fabricate LCFs from different feedstocks (pure cellulose, bleached and unbleached wood pulps, and wood chips), including unit operations of feedstock pretreatment, cellulose dissolution and regeneration, film formation, drying, hot press, and surface treatment.We have determined optimal conditions for the operations to fabricate LCFs. We have purchased the required special equipment (e.g., ball mill, film former, film dryer, plate hot-press, and roller hot-press) for fabricating large-size LCFs. We prepared LCF samples for further characterization and field tests. We did a soil degradation experiment by burying LCFs in soil. It was found that LCFs can be completely degraded in soil within 5 weeks. We demonstrated the concept of roll-to-roll continuous production of LCFs using a wet spinning machine and are working on the process optimization and operation integration. We have tested the mechanical properties of the lignocellulosic films, such as stiffness, tensile strength, and fracture toughness. We have also started collecting and reviewing the literature on the mechanics of lignocellulosic films. The results indicated that the tensile strength of LCFs is higher, but elongation is significantly lower than polyethylene film. We have completed a manuscript draft on the preparation, properties, and applications of lignocellulosic films. The proposal has been accepted by Chemical Reviews, and we will submit the manuscript to the journal soon. We conducted an experiment that will evaluate initial formulations of lignocellulose film in a greenhouse and then evaluate their rate of in-soil biodegradation in comparison to plastic biodegradable mulch. Two postdocs and five graduate students were involved in related research and outreach activities. Educational content that introduces and defines LCF for stakeholder groups was created and includes PowerPoint slides and a newsletter article. The PowerPoint slide will be narrated and made into a video in 2025. All developed content will go onto our project-specific webpage on co-PI DeVetter's "Mulch Technologies" website, where a specific webpage for our project was created and published in 2024 (https://lignocellulosicfilm.wordpress.com/). The newsletter article titled "What is lignocellulose film?" was published in the widely read "Sustainable Mulch Management" newsletter and has a readership of 259 individuals.A webinar is in development and will occur in 2025.Information has also been presented at grower, mulch manufacturer, and academic events. Based on the experiments, we conducted input-output analyses for synthesizing LCF with critical solvent (LiBr) recycled, developing a life cycle inventory considering mass and energy balances. We further used the inventory to quantify the greenhouse gas emissions for producing LCF, identifying the key raw materials and unit processes with the largest contribution. Consumer surveys as part of the impact assessment were initiated.Before conducting the survey, the teamsubmitted the survey and procedure to the IRB at Washington State University (WSU), and it was certified exempt from further IRB review (IRB# 20701-001).

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Jiansong Chen, Haishun Du, Ruolin Wang, Zhenhui Jin, Longwei Li, Yi-Cheng Wang, and Xuejun Pan. 2024. Lignocellulosic materials-based triboelectric nanogenerators for harvesting mechanical energy (Invited talk). The 7th International Conference on Nanogenerators and Piezotronics (NGPT 2024), May 19  23, 2024, Madison, WI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Xuejun Pan. 2024. Molten salt hydrate as a unique solvent for the fractionation, processing, and conversion of lignocellulosic biomass (Invited talk). The 46th Symposium on Biomaterials, Fuels and Chemicals (SBFC), April 28  May 1, 2024, Westin Alexandria of Old Town, Alexandria, VA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Haishun Du and Xuejun Pan. 2024. Sustainable preparation and multifunctional applications of nanocellulose. The 2024 AIChE Annual Meeting, October 2731, 2024, San Diego, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Jiansong Chen, Haishun Du, Yi-Cheng Wang, and Xuejun Pan. 2024. Chemical functionalized cellulose films for high-performance triboelectric nanogenerators in energy harvesting and self-powered sensing. The 2024 AIChE Annual Meeting, October 2731, 2024, San Diego, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Williams, Aidan. 2024. Introducing a New Biobased, Biodegradable Mulch: Lignocellulosic Film. American Society for Horticultural Sciences Conference. Sept. 26, 2024. Honolulu, HI. Oral presentation.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Williams, Aidan, Haishun Du, Teng Li, Yuan Yao, Xuejun Pan, and Lisa Wasko DeVetter. 2024. Introducing A New Biobased, Biodegradable Mulch: Lignocellulosic Film. AMI Agricultural Film North America Conference. July 23-24, 2024. Tampa, FL. Oral presentation.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Williams, Aidan. 2024. What is Lignocellulose Film? Trash it or Till it? Mulch Technologies Field Day. Aug. 21, 2024. Mount Vernon, WA. Oral presentation.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Williams, Aidan. 2024. What is Lignocellulose Film? Trash it or Till it? Lynden Ag Show/Small Fruit Conference. Lynden, WA. Nov. 4, 2024. Poster presentation.
  • Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Zhiqiang Pang, Ning Li, Cuihua Dong, Hairui Ji, Yang Liao, Guihua Yang, Xuejun Pan. Insights into the dissolution of cellulose in lithium bromide solution. Carbohydrate Polymer Technologies and Applications, 2024, 7, 100522.


Progress 01/01/23 to 12/31/23

Outputs
Target Audience: Graduate and undergraduate students through formal classroom instruction (BSE 460-Biorefining at UW-Madison). Graduate students participated in the research activities of this project. The general public, farmers, mulch film producers, etc. through the website, newsletter, presentations, etc. Peer researchers through seminars and conference presentations (e.g., AIChE meeting, International Society of Industrial Ecology conference). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?UW-Madison: One postdoc and two graduate students were involved in this project at the University of Wisconsin-Madison. Through this project, the postdoc and students studied the knowledge of biomass, and molten salt hydrate, and learned the skills and techniques for analysis and characterization of biomass. They were also trained in literature research, experiment design, data analysis, technical communication, and manuscript preparation for publication. The postdoc and students took the training workshops to learn how to use the instruments/equipment for material characterization, including universal test machine, TGA, contact angle, AFM, SEM, XRD, rheometer, etc. The postdoc and one student attended and presented at the 2023 AIChE meeting. WSU:One graduate student is involved in the project at Washington State University. The student has learned about soil-biodegradable mulch feedstocks and the unique attributes of LCF, experimental design and fundamentals of data analysis, technical communication to academic and non-academic audiences, and manuscript preparation. UMD:One graduate student is involved in the project at the University of Maryland, College Park. The student has learned about the mechanical testing of lignocellulosic films and how to extract key mechanical properties of the films from such testing. The student is also trained in literature study, technical communication, and technical writing. Yale:The plastic life cycle assessment literature collected was included in Yao's life cycle assessment class with 33 students, most of whom were professional master students. How have the results been disseminated to communities of interest? The ideas, results, and findings of the project were shared with students in the course "Biorefining: Energy and Products from Renewable Resources" offered annually by PI (Dr. Pan). This made more students aware of the technology developed in this project and its impacts on the area. Part of the outcomes and findings from this project were presented at the 2023 AIChE Annual Meeting to share with peers. Information about LCF was shared in a newsletter article titled, "What is lignocellulose film?", published inSustainable Mulch Management. The article has a readership of 259 individuals worldwide involved in soil-biodegradable mulch research, outreach, and manufacturing. What do you plan to do during the next reporting period to accomplish the goals? Conduct field tests of the LCFs to evaluate their performance as mulch films in comparison with commercial mulch films. Carefully characterize the LCFs fabricated from cellulose, bleached wood pulp, unbleached wood pulp, and wood powder in terms of morphological, mechanical, and chemical properties. Publish the project webpage and update the webpage quarterly to include emerging project information. Distribute emerging project information via mulch-specific social media channels, specifically Mulch_Matters Instagram and podcast accounts. Share information via webinars with an emphasis on comparisons between PE mulch and LCF. Publish information on the project data-sharing platform. Author another newsletter article in the Sustainable Mulch Management newsletter as well as leverage emerging project information and publish in trade journals and updated PowerPoint slides available on the project webpage. Disseminate information at academic and trade conferences. Begin impact assessment after webinar and conference presentations via Qualtrics surveys to assess barriers and bridges to using LCF. Continue training postdoc and graduate students through this project. Attend conferences to present and share the findings from this project. Publish peer-reviewed journal articles based on the results and findings from this project. File a patent for the method developed to fabricate films from cellulose and lignocellulose materials. Collect data onenergy consumption and mass input and output. Those data will be used for conducting techno-economic analysis and life cycle assessment.

Impacts
What was accomplished under these goals? This project is to produce fully soil-biodegradable lignocellulosic films (LCFs) from wood chips.The LCFs are expected to have satisfactory mulching performance to replace petroleum-derived plastic mulches used in horticultural crop production. The proposed extension activities will effectively deliver the research findings and technologies on soil-biodegradable mulches (BDMs) to stakeholders and the public. During this reporting period, the following activities/experiments were conducted/completed. Cellulose (wood powder) dissolution in a concentrated salt (LiBr or CaBr2) is the most critical operation to fabricate LCFs as mulch film through the proposed approach of dissolution and regeneration. Therefore, we carefully studied the dissolution process of cellulose in calcium bromide solution and lithium bromide solution, respectively. It was found that cellulose dissolution is dependent on salt concentration, temperature, pH, cellulose loading, cellulose structure, and other factors. Optimal conditions have been determined for cellulose dissolution in LiBr and CaBr2 solutions. It was also demonstrated that LCFs can be prepared from cellulose, wood pulp, and wood powder via dissolution and regeneration in the salt solutions. These results/findings are included in two manuscripts for publication. We have established a protocol to fabricate LCFs from different feedstock (pure cellulose, bleached and unbleached wood pulps, and wood chips), including unit operations of feedstock pretreatment, cellulose dissolution and regeneration, film formation, drying, hot press, and surface treatment.We have determined optimal conditions for the operations to fabricate LCFs. We have purchased the required special equipment (e.g., ball mill, film former, film dryer, plat hot-press, and roller hot-press) for fabricating large-size LCFs. We are preparing LCF samples for further characterization and field tests. We have started testing the mechanical properties of the lignocellulosic films, such as stiffness, tensile strength, and fracture toughness. We have also started collecting and reviewing the literature on the mechanics of lignocellulosic films. We developed an experiment that will evaluate initial formulations of lignocellulose film in a greenhouse and then evaluate their rate of in-soil biodegradation compared to plastic biodegradable mulch. 1 postdoc and 4 graduate students were involved in this project in related research and outreach activities. Educational content that introduces and defines LCF for stakeholder groups was created and includes PowerPoint slides and a newsletter article. The PowerPoint slide will be narrated and made into a video in 2024. All developed content will go onto our project-specific webpage on co-PIs DeVetter's "Mulch Technologies" website (https://smallfruits.wsu.edu/plastic-mulches/), which will be published in Jan 2024. The newsletter article titled, "What is lignocellulose film?" was published in the widely read "Sustainable Mulch Management" newsletter and has a readership of 259 individuals.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Jiansong Chen, Zhiqiang Pang, Haishun Du, and Xuejun Pan. Cellulose dissolution and regeneration in calcium bromide solution. 2023 AIChE Annual meeting, Nov. 510, Orlando, FL.
  • Type: Other Status: Published Year Published: 2023 Citation: Aidan Williams. 2023. What is lignocellulosic film? Sustainable Mulch Management Newsletter. Vol 2. Available online: https://smallfruits.wsu.edu/plastic-mulches/newsletter/.