Eco-friendly Polymer Nanocomposite—Properties and Processing

Abstract

This chapter mainly reviews the concept, properties and processing, and design method of the eco-friendly polymer nanocomposite (EPN), which is generally biodegradable and renewable. The major attractions of EPN are that they are environmentally friendly, sustainable, and degradable. These polymer composites can be easily composted or disposed without harming the environment. Some efforts have been made on attaining biodegradable reinforcing fillers giving improved performance of composites. Another concern is focused on employing recyclable synthetic fibers with thermoplastic composites to reduce the waste of fillers, and also some research is devoted to reusing or recycling the whole composites for the similar purpose. Simultaneously, people also would like to make composites manufactured with traditional production process become eco-friendly by extra reprocessing. Throughout the stages of development--design, appraisal, manufacture, use, reuse-recycling, and disposal--researchers are supposed to be fully engaged in reducing waste as much as possible, keeping in mind the environment all the time. A series of natural or synthetic materials have been used, such as cellulose, thermoplastic starch, etc. The challenge posed by eco-friendly composites also needs considerable attention in terms of poor bonding between matrix and fillers, loose control of fiber orientation, and difficulty in shaping nanoscale particles.

Recent advances and perspectives on starch nanocomposites for packaging applications

“…For decades, researchers encountered many challenges for the preparation of starch nanocomposites because of their limited flexibility and high hydrophilicity apart from typical nanofiller agglomeration and weak interfacial bonding at high nanofiller loadings. Furthermore, many techniques are improved to overcome these disadvantages like using TPS instead of neat starch, modified nanofillers, coupling agents, compatibilisers [6]. For instance, He et al [32] chemically modified halloysite nanotubes (HNTs) to prevent HNT agglomeration and achieved better particle dispersion within starch matrices.…”

“…The complete removal of chemical modifiers [32] or using natural modifiers like phosphatidylinositol (FPI) and citric acid [33,34] is essential for materials used in the field of food packaging. Conventional preparation techniques have been implemented to prepare starch nanocomposites like extrusion, solution casting, compression and injection moulding [6,8]. According to Madhumitha et al [28] and Scarfato et al [35] casting and extrusion are the most common manufacturing methods for material processing of starch as a non-thermoplastic polymer.…”

“…Then equal amounts of suspension are poured into moulds to control the film thickness. After that, films are dried at temperatures between 30-50 º C in an oven or at room temperature for at least 24 h [6,8,28]. Nanofillers can be incorporated into starch matrices by different means.…”

“…All components (i.e. starch, nanofillers, and plasticisers) can be fed at a single stage to the extruder with or without water [5,6,8,28]. For instance, Schmitt et al [11] mixed designated amounts of wheat starch, HNTs, glycerol and glycerol monostearate as plasticisers for 3 h in a mechanical mixer.…”

“…As such, it becomes a suitable solution to use biodegradable polymers to replace their synthetic counterparts. The major reasons to consider biopolymers as the alternative lie in their resource renewability, availability, biodegradability and ecofriendliness [1,[3][4][5][6][7][8][9].…”