Update (January 2, 2004).  This project has never been populated.  Interested students are encouraged to enquire with any of the investigators who may still have an interest in this or related research.   

This project will: separate commercial polymers from industrial remnants; develop new fibers and fabricate textile nonwoven products; and, seek to improve end-use performance of nonwovens.

Primary Faculty Participants

Professor Yan (Jonathan) Chen, School of Human Ecology (Textiles Engineering)

Professor Ioan Negulescu, School of Human Ecology (Textiles Division)

Off campus-Participants:

Dr. Timothy A. Calamari, Jr., Research Leader of the Cotton Engineering Research Unit at the USDA Southern Regional Research Center in New Orleans (cellulose chemistry and structure, nonwoven processing)

Off-campus committee members: John & Billie Collier (University of Tennessee, Knoxville)

Technical Proposal: The U.S. public increasingly recognizes the importance of facilitating the wise use of natural resources and protection of environment. This raises the need to reduce wastes by either recycling industrial materials or manufacturing products having enhanced biodegradation potential. This research aims to develop environmentally improved textile products (EITP) using recycled commercial polymers and agricultural low-value or waste materials. The objectives of this research also address evaluation of end-use performance and market compatibility of EITP. These research efforts will accomplish the general goals established in this IGERT proposal, contribute to improvement of environment and human health, and foster specialists that are highly needed in the development of value-added products. This will eventually benefit the textile, chemical, agricultural business sectors, and also rural economies.

In the United States, environmental responsibility is becoming increasingly important to most major industries, including the textiles industry. Tighter restrictions, new regulations, and increased consumers’ concerns have been critical in the development of new technologies, products, and trades that address the issues of environmental protection and human health. Substantial evidence indicates that environmental concerns influence consumer purchases. It was stated that consumers would be willing to pay about 6.6% more to purchase selected environmentally improved products [1]. Meanwhile, industries are changing their attitudes by including environmental protection as one of the industries’ new strategies. Thus, it is appropriate and timely to conduct the research on utilization of recycled polymeric materials and agricultural materials for textile end-uses. However, the textiles made of intimately blended polyester and cotton or rayon are difficult to recycle due to significant differences between physical and chemical properties of polyester and cellulosics. We proposed a scheme to separate cotton (or rayon) from these textiles and recycle it as a new lyocell fiber, viz., a fiber spun from cellulose solution [2]. The polyester component can be recycled separately in a process similar to that for obtaining the ecofriendly Fortrelâ EcoSpunâ fiber consisting of 100% recycled plastic bottles. Additionally, the lyocell

technique opens the door to sol-gel hybrids, based on the ability of cellulose to be molecularly blended in solution with synthetic polymers [3]. Hybrid systems represent the next generation of advanced fibers since they provide a route to novel combination of existing materials with potential to produce structures, morphologies and properties which are inaccessible through conventional technologies. Of a particular interest for these hybrids is the shear-induced anisotropy of lyocell systems at almost any concentration of cellulosic rod molecules, detected as a sudden increase of the viscosity while the temperature is increasing, as shown above at left [4]. It is the anisotropy of cellulose solutions, which allows production of fibers of high tenacity, close to that of polyesters, such as Tencelâ , one of the most novel chemical fibers in almost 30 years. The shear induced anisotropy allows also the formation of cellulosic microfibers--another novelty in the field--by spinning lyocell solutions through hyperbolic dies [5]. Therefore, recycling of cotton (rayon) as a composite hybrid fiber is appealing, due to new reactivities such a hybrid might possess, such as enhanced chemical reactivity (consider for example a lyocell fiber with free amino groups obtainable from a molecular composite containing acrylonitrile units).

In the textile industry, byproducts that cannot be used in conventional processes are produced during manufacturing. For instance, manufacturing segments such as clothing and home furnishings are discharging about 400 million pounds of non-biodegradable polyester remnants yearly [6]. If these remnants can be separated into shorter and open fibers, they can be blended with other fibers to produce cheaper textile products. U.S. companies are recognizing this great potential and starting to investigate the processing technology of separating (extracting) textile polymeric remnants [6]. They also seek an economical approach to manufacturing textile end-use products using recycled fibers. For this purpose, a joint project with the USDA Southern Regional Research Center (SRRC) was initialized. This project focused on fabrication and end-use performance of environmentally improved textile products (EITP). A nonwoven blanket product was produced from cotton and recycled polyester and characterized. Finishing treatments for wrinkle, flame, and microbial resistance applied to improve end-use performance. Product properties were evaluated using the Kawabata instruments at LSU and other standard methods. Such blanket products could be used for natural disaster relief goods, short-term housing needs, and auxiliary facilities for medical and health care. The experimental blanket was comparable to commercial nonwoven blankets in comfort, quality, and thermal covering performance. This indicated potential to produce low-cost nonwoven products using other recycled synthetic fibers.

Procedure & Theory. The procedure of processing recycled fibers into nonwovens is illustrated below:

Blending and Opening mixes recycled fibers with agricultural fibers such as cotton, sugarcane rind, kenaf, ramie, flax, etc., removes impurities; and opens fiber clusters into uniform and bulky fiber layers. The carding process is to separate single fibers, further remove impurities, and convert single fibers into continuous and uniform web with random fiber orientations. This is the most important procedure in producing nonwovens. Needle-punching will mechanically bond fiber web through needle entanglement to form nonwovens. These steps involve engineering. The finishing process assures product quality; here is where the chemistry comes in. Main finishes include wrinkle and flame resistant treatment using a water solution containing citric acid, tartaric acid, sodium hypophosphite catalyst, and wetting agent; antibacterial treatment using magnesium hydroperoxyacetate (MHPA); and softening treatment using commercial fabric and laundering softeners. After this comes engineering analysis. Attention will be paid to determining the optimal ratio of blending recycled fibers with other agricultural fibers, because this ratio is critical for improving quality and strength of the nonwoven products. Denoting k_i as weight rate of each mixed fiber; l_i as average length of each mixed fiber; and C_i as length irregularity of each mixed fiber, we define

.

The blended fiber length and irregularity can be calculated by

Thus, we can determine the optimal blending ratio k₁ and k₂ that leads to a minimum blended fiber length irregularity. If we want to obtain a minimum blended fiber length irregularity, the following must be met:

Equipment. The Textile Processing Laboratory at LSU is equipped with a carding machine and needle-punching machine. This will insure that most important experiments of processing recycled fibers can be carried out. Additional instrumentation is available at the USDA center in New Orleans.

Number of IGERT apprentices to be recruited and probable home departments: Two: both could come from the School of Human Ecology, or one might come from Chemistry.

Consistency with the Macromolecular Education, Research, and Training Theme: The textile industry is a huge consumer of polymer materials, which must be understood at the molecular scale and also as engineered products. Manufacturing advance of synthetic fibers and textiles always relies on fundamental development of new polymers and modifications to existing polymers.

How does the project form a vector cross-product of existing research themes by the participants?

Existing research directions. Chen's expertise is processing technology of natural and synthetic fiber materials, instrumental measurement and quality evaluation of textile products, and fabric mechanics. Negulescu specializes in the chemistry of polymers and textiles, characterization of synthetic and natural polymers, and recycling of polymeric materials. Calamari brings expertise in cellulose chemistry, particularly in the area of the morphological conversion of the various crystalline forms of cellulose, textile and nonwoven processing, new product development from natural fibers, and characterization and quality evaluation of fibers, fabrics, and nonwovens.

New research direction. This team project will focus on recycling of polymer wastes, such as polyolefin remnant and polyester remnant, and on processing of environmentally improved textile products. The above two research targets cover two different technical areas, fundamental polymer science and advanced textiles processing. Teamwork is required to implement this research program. Dr. Negulescu will be responsible for supervising a Ph.D. student with concentration on recycling of natural (cotton) and synthetic polymers by developing new fiber forming compositions, while Dr. Chen will guide a Ph.D. student with research emphasis on processing of recycled synthetic and agricultural fibers, and evaluation of textile end-use performances of the recycled polymer products. Dr. Calamari will provide first-rate training opportunities for the Ph.D. students in these research activities, with particular emphasis on fabrication and finishing of nonwoven products from recycled polymer fibers and agricultural fibers. The research experience and expertise possessed by the faculty team provides an extended platform for student training in fundamental and applied polymer technology.

How do students benefit from this team-oriented project, beyond what would be available to them from either advisor separately? Macromolecular students are often chemistry-centered. This makes them familiar with organic chemistry. However, they generally pay less attention to industrial areas of applied polymer materials, such as synthetic fiber manufacture and textile manufacture. Knowledge of manufacture of applied polymer materials and consumer polymer products may act as a bridge between polymer laboratories and markets. This will help the macromolecular students to understand and foresee marketing potential, industrial trends, and consumer needs. Through this team-oriented project, we create a special training opportunity for the macromolecular students to extend research ability and enhance competence in either academic or industrial career.

Interdisciplinary Strengths: The two professors have very different backgrounds: textiles engineering and synthetic chemistry /polymer science. They nevertheless have a close working relationship and are involved in many cooperative research projects in textiles. Involvement of the off-campus expert will bring excellent research experience and unique research facilities, enabling students to train in a federal research center. Finally, all these participants are working closely in regional extension service [6-8].

Briefly describe the support level available to each individual faculty or off-campus participant (i.e., without IGERT): Chen has research funding of $200,000 from state and industrial sources. Negulescu’s annual research support is $200,000 from state sources. Research funding for Dr. Calamari is mainly from the U.S. Department of Agriculture, Cotton Corporation, and other industrial supporters.

Commitment of faculty and off-campus participants to work side-by-side with apprentices. The faculty and off-campus expert will provide one-month intensive supervision for apprentices. Summer is the best time for these faculty to work side-by-side with students. Students can take advantage of training in the USDA Southern Regional Research Center at New Orleans. During this training time, the off-campus expert will play a key role in guiding the students. Dr. Chen is the supervisor of the Textile Processing Laboratory and is directing the research project of Industrial Textile Products from Sugar Cane and Kenaf Fibers in the LSU Agricultural Center. Dr. Chen and Dr. Negulescu are also representing the Louisiana Agricultural Experiment Station in the Southern Regional Research Technical Committee (S272). They can oversee the team research activities when either one of them is making a short-term leave. Dr. Calamari will also have other senior scientists available in the USDA Southern Regional Research Center to assume technical advice and laboratory supervision for the student if he must be gone for a short while.

References

1. Hager, M., What You Can Do to Save the Earth, Consumers Digest, March/April 1990, 62-66.
2. Ioan I. Negulescu, Hyojung Kwon, Billie J. Collier, John R. Collier, and Ajit Pendse, A Scheme for Recycling Cotton from Cotton/Polyester Fabrics, Textile Chemist and Colorist, Vol. 30, No. 6, 31-35, (1998)
3. Ioan I. Negulescu, Billie J. Collier and John R. Collier, Cellulose/Synthetic Polymers Molecular Composites for Fibers and Films, Book of Papers, 1998 American Association of Textile Chemists and Colorists International Conference & Exhibition, p.608
4. Simioan Petrovan, Ioan I. Negulescu, John R. Collier and Billie J. Collier, Rheology of Cellulosic and Lignocellulosic N-Methylmorpholine N-Oxide Solutions, Polymer Preprints, 40(2), 746-48, 1999
5. US Patent Application (for LSU), Cellulosic Microfibers, by John R. Collier, Ioan I. Negulescu and Billie J. Collier. October 17, 1997.
6. Goynes, W. R., Tao, W., Graves, E. E., Day, M., Yachmenev, V., Calamari, T. A., Peters, J. G., Negulescu, I. I., and Chen, Y., Fabrication and Finishing of Nonwoven Blankets from Recycled Fibers, submitted for AATCC 1999 International Technical Paper Competition.
7. Negulescu, I. I., Despa, S., Chen, J. (Y.), Collier, B. J., Despa, M., Denes, A., Sarmadi, M., and Denes, F. S., Characterization of Polyester Fabrics Treated in Electrical Discharges of Radio-Frequency, Textile Research Journal, in press.
8. Tao, W., Yu, C., Calamari, T. A., and Chen, Y., Preparation and Characterization of Kenaf/Cotton Blended Fabrics, Textile Research Journal, in press.