Thermoplastics from agricultural materials

Polymer packaging is widely used in all industry sectors food, cosmetics, health and care, chemicals, transportation, distribution, industrial and agricultural products, and so om A key role of packaging is to ensure the protection of the product it contains. The packagiug prevents the product from external contamination and it maintains its quahty. But when a product is brought into contact with a thermoplastic material, transfer of compounds occur from the material to the product (migration) or from the product to the rrraterial (sorption) (Safa and Bourelle, 1999 Auras et al., 2006). 

Wood-thermoplastic composites usually consist of wood flour, thermoplastic, and various additives. The wood used in WPCs mostly refers to wood flour or wood fibers. Apart from woody materials, the agricultural plant residues, such as stems, stalks, leave, and seed hairs could also be used as a filler to manufacture WPCs. Generally, wood fiber is the most abundantly used plant fiber due to their extensive use in pulp and paper industries. Commercial composite products typically contain approximately 50 % wood. In some cases, some products only contain little wood, while others contain as much as 70 %. It has been proved that material compositions is highly related to the weathering of WPCs. Therefore, it is imperative to understand the chemical constituents and physical properties of wood. 

Fabrication. Processes for fabricating solid fuel pellets from a variety of feedstocks, particulady RDF, wood, and wood and agricultural residues, have been developed. The pellets are manufactured by extrusion and other techniques and, in some cases, a binding agent such as a thermoplastic resin is incorporated during fabrication. The fabricated products are reported to be more uniform in combustion characteristics than the raw biomass. Depending on the composition of the additives in the pelletized fuel, the heat of combustion can be higher or lower than that of the unpelletized material. 

The transformation of starch granules into thermoplastic materials is one of the major issues within the hroad field of novel polymers from renewable resources, as highlighted in Chapter 15, because of the ready availability of low cost starch from a variety of agricultural activities throughout the world, alheit in diffoent macromolecular... 

PLA is a most promising biopolymer, since it offers unique features of biodegradability as well as thermoplastic processability. PLA is used for many different applications, from packaging to agricultural products and disposable materials, as well as in medicine, surgery and pharmaceutical fields. ° ... 

Specialty reprocessing plants have been also developed. For example, fully automatic plant was designed for separating copper wire, PE and PVC into clean, ready to re-use materials. Similar specialized plants have been designed to clean and separate PCW from the agricultural scrap (mostly PE and PVC films), from household (a variety of packa g materials), or from the industrial waste streams comprising thermosets and thermoplastics, etc.[5]. 

Starch is the most commonly used agricultural raw material. Starch is inexpensive, widely available and relatively easy to handle. All-starch bioplastics are made from thermoplastic starch and formed with standard techniques for synthetic polymer films such as extmsion or injection moulding. The use of... 

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