Development of Sustainable and Cost-Competitive Injection-Molded Pieces of Partially Bio-Based Polyethylene Terephthalate through the Valorization of Cotton Textile Waste.

Sergi Montava-Jordà,Nestor Montanes,Santiago Ferrandiz-Bou,Luis Quiles-Carrillo,Sergio Torres-Giner

doi:10.3390/ijms20061378

Abstract

This study presents the valorization of cotton waste from the textile industry for the development of sustainable and cost-competitive biopolymer composites. The as-received linter of recycled cotton was first chopped to obtain short fibers, called recycled cotton fibers (RCFs), which were thereafter melt-compounded in a twin-screw extruder with partially bio-based polyethylene terephthalate (bio-PET) and shaped into pieces by injection molding. It was observed that the incorporation of RCF, in the 1–10 wt% range, successfully increased rigidity and hardness of bio-PET. However, particularly at the highest fiber contents, the ductility and toughness of the pieces were considerably impaired due to the poor interfacial adhesion of the fibers to the biopolyester matrix. Interestingly, RCF acted as an effective nucleating agent for the bio-PET crystallization and it also increased thermal resistance. In addition, the overall dimensional stability of the pieces was improved as a function of the fiber loading. Therefore, bio-PET pieces containing 3–5 wt% RCF presented very balanced properties in terms of mechanical strength, toughness, and thermal resistance. The resultant biopolymer composite pieces can be of interest in rigid food packaging and related applications, contributing positively to the optimization of the integrated biorefinery system design and also to the valorization of textile wastes.

Highlights

The future scarcity of oil sources and the current strong awareness of waste disposal issues in modern society are two of the main drivers behind the interest, at both academic and industrial levels, in the use of bioplastics in a variety of consumer products
This study presents the valorization of cotton waste from the textile industry for the development of sustainable and cost-competitive biopolymer composites
The pieces became darker as the weight percentage of recycled cotton fibers (RCFs) increased, developing an intense grey-to-brown color

Summary

Introduction

The future scarcity of oil sources and the current strong awareness of waste disposal issues in modern society are two of the main drivers behind the interest, at both academic and industrial levels, in the use of bioplastics in a variety of consumer products. Biopolymers will play an important role in the bioeconomy and undoubtedly shape the future of the packaging industry [2] In this context, the European Commission (EC) has recently published a Packaging and Packaging Waste Directive laying out a strategy for plastics in a Circular Economy, which includes a ban on single-use plastics by the end of 2020 [3]. Bio-based polymers are referred to any kind of polymer that is produced from renewable resources, which includes both naturally occurring polymers and synthetic polymers produced by means of monomers obtained from biological sources. Biodegradable polymers include those polymers whose physical and chemical properties undergo deterioration and completely degrade when exposed to microorganisms. Articles fully made of biodegradable polymers can be compostable according to the specifications of international standards, for instance EN 13432 and ASTM D6400

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Results

Conclusion