Agropolymer Based

These biopolymers are obtained from biomass by fractionation [7]. They are further divided into two categories polysaccharides, and proteins and lipids. Polysaccharides are derived from starches (wheat, potato, maize), lignocellulosic products (cellulose), pectins, chitosans, and gums. Proteins and lipids can be either animal derived (casein, whey, gelatin, collagen), or plant derived (soya, gluten). These materials and their derivatives offer a wide range of properties and applications. 

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Depending on their origins, biopolymers used as matrices in composite materials are divided into three main classes agropolymer based (renewable sources), microbially derived, and chemically synthesized. Some authors also mention a fourth class, which consists of blends of the aforementioned three classes. 

We can classify the different biodegradable and bio-based polymers into two major families agropolymers (categoiy a) and biodegradable polyesters (categories b and c). To illustrate the latter, the next section focuses on the description of biodegradable polyesters, from synthesis to application. 

Protein-based materials have also been abundantly discussed in other publications [ZHA08], The next section of this chapter is, therefore, primarily oriented toward one example of an agropolymer starch. World production of starch-based materials for bioplastic applications is far from negligible. Put differently, it is greater than or ecpral to that of PLA. 

Bionanocomposites are an ecological alternative to conventional nanocomposites based on petroleum-derived polymers, as they are based on biodegradable polymers obtained from renewable resources. Biomass is the source of agropolymers like starch and cellulose and also of monomers used to chemically synthesize polymers like polylactic acid (PLA). Other kinds of biopolymers, e.g., xanthan gum and poly (hydroxyalkanoates), are produced by microorganisms. Even though most of the bionanocomposites reported in the hterature are based on layered sihcates, the number of examples illustrating the use of fibrous clays in the preparation of new bionanocomposites is growing rapidly. 

Like polymers, biodegradable polymers have been classified using distinct methods, including methods based on polymer origin (synthesis), renewability content, and biodegradability level. The most prominent and well-established method is the classification based on synthetic procedmes. In broad terms, these polymers are classified into two main categories (i) agropolymers (obtained from biomass) and (ii) biopolyesters (natural or synthetic biopolymers). Biopolyesters is itself a broad term that includes three subclasses (a) microbially produced polymers (b) polymers synthesized... 

Agropolymers represent two large groups of polymers polysaccharides and protein-based polymers. Here, we describe both classes in detail. 

Among the different categories of biodegradable plastics obtained from agropolymers, both starch/polyesters blends and microbial biodegradable plastics satisfied the majority of requirements asked by the plastic packaging industries (material qualities, processability, performances, etc.). Other bioplastics based on natural polysaccharides or proteins are mainly interesting for their low cost but their non-reproduetive quality and lower performances are still a handicap. 

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