Progress 03/01/03 to 09/30/06
Outputs
In the last 3.5 years, we have worked on both the PLA fibers and inkjet printing for the Multi-State Project Objective: 1) To develop value added products from renewable and recyclable resources. Nebraska Sub-Objective: To develop textile products from polylactide; and Multi-State Project Objective: 2) To develop bioprocessing and related new technologies for textile applications. Nebraska Sub-Objective:To develop new technologies for digital textile printing. For Objective 1, we have systematically studied the dyeing behavior of PLA,and the hydrolysis of PLA during dyeing. We are the first to report that PLA hydrolyzed substantially in dyeing. We then focused our effort on finding better dyeing conditions for PLA to obtain high dye uptake, better colorfastness with less damage. Our other effort was on understanding the hydrolysis mechanism of PLA and the effect of PLLA and PDLA on hydrolysis. The following is the summary of some of our work. Dyeing conditions such as
temperature, pH, ramping rate and holding time were investigated from the viewpoint of a dyer. With considerations to % dye exhaustion, color consistency, levelness, and mechanical property retention of the fiber, an industrial applicable PLA (polylactide) dyeing procedure was proposed. Ten popular disperse dyes with different energy levels and chemical constitutions were used to compare their exhaustion, color yield, and colorfastness on PLA and PET. Various disperse dyes are recommended that possibly will have high exhaustion on PLA. The dyes with solubility parameters close to that of PLA are recommended for further testing to find if they may have high exhaustion on PLA. These dyes include nitrodiphenyl amines, monoazos, methines, and other parent structures. General structures are proposed for monoazo, anthraquinone, diphenyl amine, disazo, quinoline, and methine dyes that possibly will have high exhaustion on PLA if they are synthesized. For Objective 2, we have focused on
developing new technologies for inkjet printing to improve the properties of the printed goods. We also spent much efforts on understanding the effects of printhouse conditions on color repeatability in inkjet printing. This is one of the major challenges facing inkjet printing. More details of our work are as follows. Cotton fabric inkjet printing with acid dyes was investigated. Quaternary ammonium (choline chloride (CC)), and crosslinking agents (DMDHEU and BTCA), were used for the examination in the uptake of acid dyes on cotton. Steaming time and temperature, wrapping paper, and the position of the fabric in the steamer are investigated for the consideration of color consistency of reactive inkjet printed cotton fabrics. The effects of printhouse humidity and temperature on shade depths of three typical colors, black, blue and yellow, are investigated. Cotton, silk and nylon 6,6 fabrics were used for this study with reactive, acid and acid dye inks, respectively. Possibilities of
using UV absorbers to improve lightfastness of inkjet prints are explored. Up to 1-class increase of AATCC lightfastness was obtained by adding a UV absorber onto a printed fabric.
Impacts
Our study on PLA will improve the dyeing properties of PLA and the quality of the PLA textiles.It will also result in stronger PLA and the PLA materials that can last long. This will increase the consumption of PLA and add significant value to our corn and other starch based crops. Our study on PLA hydrolysis also provides insights on controlled hydrolysis of PLA in medical applications such as drug controlled release and biodegradable scaffolds. Our use of the molecular modeling software MS Modeling 3.0, available from Accelrys for the study on the resistance of PLA blends to hydrolysis also developed a new use of the software in polymer hydrolysis. Our work on inkjet printing developed a cellulose product that can be printed by acid inks. Such an invention substantially simplified the inkjet printing and provided possibility of printing cotton blends using one ink. Our work on finding the printhouse conditions that affect color reproduceability is crucial to the
large scale production of textile materials using inkjet technology. Without color reproduceability, the digital printing technology will never be used in textile industry. Our work on improving lightfastness of inkjet printed goods is also very important to the quality improvement of the inkjet printed goods, especially for artworks, which is the mainly area which uses inkjet printing technology. The results from this study is also very important to the large scale application of digital printing technology.
Publications
- -Yang, Y., and Naarani, V., 2006. Improvement of the lightfastness of reactive inkjet printed cotton, Dyes and Pigments In press.
- -Karst, D., Yang, Y, and Tanaka, G. 2006. An Explanation of Increased Hydrolysis of the -(1,4)-Glycosidic Linkages of Grafted Cellulose Using Molecular Modeling. Polymer, 47(18), 6464-6471(2006).
- -Karst, D., and Yang, Y. 2006. Molecular modeling study of the resistance of PLA to hydrolysis based on the blending of PLLA and PDLA, Polymer, 47(13), 4845-4850 (2006). -Yang, Y., Naarani, V., Thillainayagam, V., and Reddy, N., 2006. Effects of printhouse humidity and temperature on quality of ink jet printed cotton, silk and nylon fabrics, Journal of Imaging Science and Technology, 50(2), 181-186(2006).
- -Yang, Y., Han, S., Fan, Q., and Ugbolue, S.C., 2005. Nanoclay and modified nanoclay as sorbents for anionic, cationic and nonionic dyes, Textile Research Journal, 75(8), 622-627(2005).
- -Reddy, N. and Yang, Y., 2005. Biofibers from agricultural byproducts for industrial applications, Trends in Biotechnology, 23(1) 22-27 (2005).
- -Yang, Y., and Naarani, V., 2004. Effect of steaming conditions on color and consistency of inkjet printed cotton using reactive dyes, Coloration Technology 120(3) 127-131(2004).
- -Yang, Y., and Huda, S., 2003. Comparison of disperse dye exhaustion, color yield, and colorfastness between polylactide and poly(ethylene terephthalate), J. Applied Polym Sci., 90(12), 3285-3290 (2003).
- -Yang, Y., and Li, S., 2003. Cotton fabric inkjet printing with acid dyes, Textile Res. J., 73(9) 809-814(2003).
- -Yang, Y., and Huda, S., 2003. Dyeing conditions and their effects on mechanical properties of polylactide fabric, AATCC Review, 3(8), 56-61 (2003).
- -Yang, Y., Li, S., and Stewart, N., 2003. One-step inkjet printing and durable press finishing, AATCC Review, 3(3) 29-31(2003).
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Progress 10/01/04 to 09/30/05
Outputs
Multi-State Project Objective 1: To develop value added products from renewable and recyclable resources. Nebraska Sub-Objective: To develop textile products from polylactide The arrangements of L-lactide and D-lactide in poly(L-lactide-co-D-lactide) copolymers that give polylactide improved resistance to hydrolysis are found using molecular modeling. Amorphous structures of these copolymers were created, and molecular dynamics simulations and energy minimizations were run to calculate their potential energies before and after hydrolysis. The interaction energies between the L-lactide and D-lactide segments and between themselves were investigated, and their effect on hydrolysis of the copolymers were explained. The effect of nanoclay on dye sorption was investigated for potential use in PLA to improve its dyeability and to decrease its hydrolysis during dyeing. Nanoclay has excellent sorption of anionic and nonionic dyes, much better than any fibers currently
available on market. The study indicated that it is possible to use nanoclay in PLA fiber to improve the dye uptake of PLA. The potential advantages and possible disadvantages of using nanotechnology for textiles were explored. Multi-State Project Objective 2: To develop bioprocessing and related new technologies for textile applications. Nebraska Sub-Objective: To develop new technologies for digital textile printing. Unlike traditional printing, inkjet printing has thickeners and other auxiliaries evenly distributed in the fabric and dried before printing, and uses inks with very low viscosity. Because of these differences and other uniqueness, color repeatability of inkjet printed fabrics is poor. A ∆E (CIE) larger than 5 is commonly observed from the same fabrics with the same treatment and inks, and from the same printer. In order to control the color variations in inkjet printing, we have studied the effects of steaming and printhouse conditions on color repeatability.
Parameters investigated include steaming time and temperature, wrapping paper, the position of fabrics in the steamer, and the printhouse humidity and temperature. The possible approaches in minimizing shade variations in inkjet printing are recommended.
Impacts
The better resistance of PLA to hydrolysis and the better dye sorption behavior of PLA are critical to the successful applilcation of this biodegradable synthetic polymer in textiles. The application of PLA in textiles will add value to Nebraska and US agrucultural products and byproducts, move the textile and fiber industry away from the current heavy reliance on petroleum. The understanding of and the improvement in inkjet printing technology for textiles will enhance the competitiveness of the US textile industry in the global economy. Our work contributes to the improvement of inkjet printing quality and will lead to more and better applications of inkjet printing in textiles.
Publications
- -Yang, Y., Naarani, V. and Thillainayagam, V, Color repeatability in inkjet printing, 2005 Book of Papers--AATCC International Conference & Exhibition, American Association of Textile Chemists and Colorists, Research Triangle Park, NC, 2005, pp. 201-207.
- -Karst, D., and Yang, Y., Improving the resistance of polylactide to hydrolysis based on the arrangement of L- and D-lactide in poly(L-lactide-co-D-lactide). PMSE (Polymeric Material Science and Engineering) Preprints. American Chemical Society, Division of Polymer Chemistry, NY, NY. 93 775-776 (2005).
- -Karst, D., and Yang, Y. Potential advantages and risks of nanotechnology for textiles, AATCC Review, accepted 2005.
- -Yang, Y., Naarani, V., and Thillainayagam, V. Effects of printhouse humidity and temperature on quality of inkjet printed cotton, silk and nylon fabrics, Journal of Imaging Science and Technology, accepted 2005.
- -Yang, Y., Han, S., Fan, Q., and Ugbolue, S.C., Nanoclay and modified nanoclay as sorbents for anionic, cationic and nonionic dyes, Textile Research Journal, accepted 2005.
- - Karst, D., and Yang, Y., Using the solubility parameter to explain disperse dye sorption on PLA, J. Appl. Polym. Sci., 96(2), 416-422(2005).
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Progress 10/01/03 to 09/30/04
Outputs
Comparison of disperse dye exhaustion, color yield, and colorfastness between PLA and PET Ten popular disperse dyes with different energy levels and chemical constitutions were used to compare their exhaustion, color yield, and colorfastness on PLA and PET. Only two out of the ten dyes had exhaustions higher than 80% on PLA at 2 % owf. Five out of the ten dyes had exhaustions less than 50%. All ten dyes had more than 90% exhaustion on PET. There was no obvious pattern as for which energy level or structure class provided dye exhaustion better than others. Although PLA had lower dye exhaustion than PET, it had higher color yield. Based on the ten dyes examined, the color yield of PLA was about 30% higher than PET. This means that even with low dye uptake, PLA could have the similar apparent shade depth to PET if the same dyeing conditions are applied. Our study supported that the lower reflectance, or reflectivity, of PLA contributes to the higher color yield of PLA
than PET. Quantitative relation between the shade depth of PLA and PET based on their dye sorption was developed. Disperse dyes examined had lower washing and crocking fastness on PLA than on PET. The differences were about 0.5 to 1.0-Class. If the comparison was based on the same dye uptake, the differences might be larger. The differences in light fastness between the two fibers were smaller than that in washing and crocking fastnesses. The light fastness of disperse dyes on PLA is expected to be even better if the comparison is based on the same dye uptake on both fibers. Cotton fabric inkjet printing with acid dyes Cotton fabric inkjet printing with acid dyes was investigated. Quaternary ammonium (choline chloride (CC)), and crosslinking agents (DMDHEU and BTCA), were used for the examination in the uptake of acid dyes on cotton. The concentrations of the chemicals, the finishing conditions, and the inkjet printing processes were explored. It was found that with the aid of
crosslinkers, acid inks could be used satisfactorily on cotton. Using CC in addition to the crosslinkers improved acid dye uptake only slightly more than using the crosslinking agent alone. A disadvantage of using CC was that the loose dye stained onto white unprinted areas during laundering. It was proposed that the main function of crosslinkers was not only to chemically link the dye to cellulose, but also to form a crosslinked network to block the entrance of the fiber pores where the dye molecules previously penetrated. Steaming conditions and color consistency of reactive inkjet printed cotton Steaming time and temperature, wrapping paper, and the position of the fabric in the steamer are investigated for the consideration of color consistency of reactive inkjet printed cotton fabrics. Two of the commonly used steamers, a high temperature and an atmospheric steamers were examined. The reactive dye fixation and hydrolysis concepts were used to explain the shade variations.
Recommendable steaming conditions for both steamers are provided. The information provided and discussed in this paper should be interesting to the textile and apparel designers, textile producers and inkjet steamer manufacturers.
Impacts
The study on dyeing behaviors of PLA provides important information to the textile industry for the use of this new material. The success of PLA in textile determines the consumption of PLA and therefore the value addition to the US agriculture due to the large consumption and high price of textile materials. The study on developing technology for the inkjet printing of cellulose materials using acid inks substantially decreases the complexity of inkjet printing. The study on color consistency in inkjet printing provides critical information on quality of printed goods. Both of these studies are essential to the promotion on use of cotton and other cellulose fibers.
Publications
- Yang, Y., and Naarani, V., Effect of steaming conditions on color and consistency of inkjet printed cotton using reactive dyes, Coloration Technology 120(3) 127-131(2004).
- Yang, Y., and Huda, S., Comparison of disperse dye exhaustion, color yield, and colorfastness between polylactide and poly(ethylene terephthalate), J. Applied Polym Sci., 90(12), 3285-3290 (2003).
- Yang, Y., and Li, S., Cotton fabric inkjet printing with acid dyes, Textile Res. J., 73(9) 809-814(2003).
- Naarani, V., and Yang, Y., Appropriate steaming conditions for color consistency and quality of digitally printed fabric, in Section 5. Advancement in Textiles, 2003 Conference of the International Textile and Apparel Association, Savannah, GA, Nov. 8-11, 2003 (abstract).
- Naarani, V., and Yang, Y., Effect of steaming conditions on color consistency of digitally printed fabric, 2003 Book of Papers--AATCC International Conference & Exhibition, American Association of Textile Chemists and Colorists, Research Triangle Park, NC, 2003, p40 (abstract)
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Progress 10/01/02 to 09/30/03
Outputs
Objective 1: To develop value added products from renewable and recyclable resources Dyeing conditions such as temperature, pH, ramping rate and holding time were investigated from the viewpoint of a dyer. Eleven disperse dyes were used for this study, based on their popularity, different energy levels, chemical constitutions, and pH sensitivities. With considerations to % dye exhaustion, color consistency, levelness, and mechanical property retention of the fiber, an industrial applicable PLA (polylactide) dyeing procedure was proposed. Objective 2: To develop bioprocessing and related new technologies for textiles An inkjet printing technology that combines printing and durable press finishing in one process was developed. Both acid and reactive dyes were examined. Alkaline catalyst was not required for reactive printing using this process. Normal pretreatment of the fabrics was also unnecessary. The crosslinking agents evaluated were DMDHEU
(dimethyloldihydroxyethylene urea) and BTCA (butanetetracarboxylic acid). The fabrics thus processed had satisfactory dye fixation and colorfastness which were the same as, or better than, the color quality from conventional inkjet printing. In addition, printed fabrics had high smoothness appearance grade, indicating high dimensional stability, resiliency, and durable press capability.
Impacts
PLA is a new fiber to the textile industry. This work provided the appropriate dyeing conditions for the textile industry with considerations of important factors in a dyehouse. It is an important literature for the understanding of the properties and dyeing behavior of the fiber. The inkjet printing technology developed allowed people to use a single set of inks to print on most of the textile materials with excellent colorfastness, high smoothness appearance grade, high dimensional stability, resiliency and durable press capability.
Publications
- Yang, Y., and Li, S., Cotton fabric inkjet printing with acid dyes, Textile Res. J., 73(9) 809-814(2003).
- Yang, Y., and Huda, S., Dyeing conditions and their effects on mechanical properties of polylactide fabric, AATCC Review, 3(8), 56-61 (2003).
- Yang, Y., Li, S., and Stewart, N., One-step inkjet printing and durable press finishing, AATCC Review, 3(3) 29-31(2003).
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