by Yi Shen
Fast fashion, mass-production of high-fashion designs based on replicating catwalk trends, has quickly attracted consumers’ attention in the past decade due to its low price. While the fashion industry remains the second most polluting in our society, the development of fast fashion brands keeps booming. Meanwhile, environmentalists have realized the urgent need to address the negative impacts of this industry [1]. The overwhelming demand for new clothes accelerated the clothing production and supply chain. The manufacturing process releases pollutants including, but not limited to, heavy metal and pesticides as well as uses excess water and contaminates the soil. Tons of water is required in clothing manufacturing while old clothes are dumped into landfills. Only approximately 15% of post-consumer textile waste is reused or recycled and 35% of that is resold, as reported in 2014 by the Council for Textile Recycling [1,2,3]. 85% of clothing and textile ultimately becomes one-time use, wasting tons of material that are both natural and synthetic, overusing natural resources, and leaving immeasurable types of pollutants in the environment [2,3]. To integrate sustainability into clothing factories, educating the manufacturers and the general public is essential. Understanding the nature of different textiles, evaluating the energy/resource cost associated, identifying possible ways to reduce waste of textile, and perhaps devising more ideas for reuse and recycling can provide potential solutions to addressing this pressing situation.
Figure 1. clothes mountain at an exhibition (Source)
Chemical makeup and manufacture of textile fibers-polymers:
The history of clothes can be traced back to around ten thousand years ago, at which time animal skin, fur, and leaves were the major materials used to cover the human body. The evolution of clothing material took place along with the industrial revolutions. Before the polymer factory was well-established, cotton, wool, silk, and several other natural products were primarily used for making clothes [4]. Nowadays, the evolution of science and technology brings consumers new types of materials with unique and valuable properties: softness, stretchiness, high strength, and most importantly, many are cheap. Unlike naturally occurring polymers such as cotton and wool, synthetic polymers such as polyesters, polyacrylics, and polyamides (nylon) can be easily manipulated from the smallest synthetic unit (monomer) [5].
Figure 2. annual global fiber production [5]
Polyester contains ester groups in the main chain and is made through a condensation method in the industry. Being the most used synthetic material in clothes production, polyester is produced on a scale of 30 million tons annually. Nylon or synthetic polyamides are urea-formaldehyde resins, resistant to heat, noncombustible, and can be colored. Polyacrylonitrile is often used to make knitted clothing [6]. Despite the type of polymer, natural or synthetic, chemical treatments, such as dyeing and bleaching, are always required, resulting in huge amounts of polluted water [2,3]. Although polyester is a considerably greener replacement for polyolefins, used in plastic bags, tremendous amounts of polyester clothing end up in landfills or are incinerated, both highly unsustainable ways to dispose of these materials.
Figure 3. polyester chemical representation and clothes tag (left), nylon chemical representation and clothes tag (middle), and polyacrylic chemical (right).
Our lab, led by Professor Paula Diaconescu at UCLA, has been working on new methods to synthesize polyesters and other types of polymers that are considered biodegradable. In fact, the degradation property of polymers is related to the length and composition of the main chain of the polymer, whether there are side chains, and what pendant groups are present. Finding a good balance between the use and disposal of polymers requires a lot of research.
Figure 4. half-lives of polymeric substrates, the energy cost to break the significant bond in the polymer chain, and enzymatic rate constants for biocatalytic activity towards plastics used in the textile industry [7].
Potential solutions to a sustainable future in the textile industry:
Implementation of new chemistry and technology into the production of textile, to reduce the chemical pollution in the manufacturing as well as lower the energy cost in the process, has been one of the major topics in sustainable fiber production. Meanwhile, more and more brands have identified new ways to reuse, recycle, and resale their clothes. More fashion brands, including fast fashion such as H&M, have introduced new policies for collecting any of their unwanted clothes, offering renting options instead of buying, and using recycled polyesters for making new clothes. Another good option for individuals to close the loop is to donate unwanted clothes to thrift stores, where consumers can also find useful and fashionable items at low prices, as well as donate to organizations for unhoused neighbors.
Figure 5: sustainable options provided by H&M (Source)
It is very important for both, the textile industry and consumers, to realize the importance of textile recycling and reuse. Data collected in scientific review shows that within 4.7 million tons of textile generated from virgin building blocks, only 1.2 million tons are being reused, and 0.73 million tons are being recycled [7]. This shows some improvement towards a more sustainable future for textile, but greater efforts are needed to find better ways for saving the material and reducing waste and the pollutants associated with it. Furthermore, a change in consumers’ opinions on reusing, instead of purchasing, and recycling, instead of needing newly-made material, should occur to further implement a close loop on textile production.
Figure 6. Different recycling routes for collected and sorted textile materials include fiber-to-fiber or even textile-to-textile recycling [7].
References:
- Ekstrom, K. M.; Salomonson, N., Reuse and Recycling of Clothing and Textiles-A Network Approach. Journal of Macromarketing 2014, 34 (3), 383-399.
- Connell, K. Y. H.; Kozar, J. M., Environmentally Sustainable Clothing Consumption: Knowledge, Attitudes, and Behavior. In Roadmap to Sustainable Textiles and Clothing: Environmental and Social Aspects of Textiles and Clothing Supply Chain, Muthu, S. S., Ed. 2014; pp 41-61.
- Harris, F.; Roby, H.; Dibb, S., Sustainable clothing: challenges, barriers and interventions for encouraging more sustainable consumer behaviour. International Journal of Consumer Studies 2016, 40 (3), 309-318.
- https://www.thoughtco.com/history-of-clothing-1991476#:~:text=The%20first%20clothes%20were%20made,at%20least%2030%2C000%20years%20ago.
- https://vartest.com/resources/technology-portal/polymers-in-textile-fibers/#:~:text=The%20Vast%20Majority%20Of%20Textile,covalently%20bonded%20to%20one%20another.
- https://www.slideshare.net/maharshiavyas/polymers-in-textile-industries
- Jonsson, C.; Wei, R.; Biundo, A.; Landberg, J.; Bour, L. S.; Pezzotti, F.; Toca, A.; Jacques, L. M.; Bornscheuer, U. T.; Syren, P. O., Biocatalysis in the Recycling Landscape for Synthetic Polymers and Plastics towards Circular Textiles. Chemsuschem.
Yi is part of the 2018-2019 INFEWS program cohort and a PhD candidate in the Department of Chemistry and Biochemistry at UCLA. Her research focuses on developing electrochemical systems using redox-switchable catalysts for the synthesis of biodegradable, block co-polymers.
This article is part of the INFEWS Social Media Series.