Biodegradable fillers

The solid polymeric starch granules with their defined structures and crystallinities can be incorporated as biodegradable filler into nonbiodegradable synthetic polymers... 

When chloroprene was grafted onto cationic aminated starch, a latex was obtained that imparted wet strength to paper and also served as a pressureless adhesive for wood 2951 Starch dialdehyde when grafted with acrylonitrile, methyl methacrylate, or both, produced a biodegradable filler for poly (vinyl chloride) plastics.2942 Starch xanthates grafted with vinyl monomers were also used to produce additives for reinforced foamed rubber.2944,2945... 

The resulting films display the t ical properties of a thermoplastic elastomer. Depending on the conditions of purification, also fully amorphous poly(/3-hydroxyoctanoate) films can be obtained. Nanocomposite materials can be prepared when using this latex as a matrix and using in addition a colloidal suspension of hydrolyzed starch or cellulose whiskers as a natural and biodegradable filler. The properties are strongly dependent on the aspect ratio of the whiskers (23). 

Controlled Degradability. This has been produced by use of biodegradable fillers such as starch powder. Once the flller has disappeared, the polymer crumbles, and the high surface area accelerates oxidative and biodegradation. 

In the case of PHA/cellulose whisker materials, studies were conducted using a latex of poly(3-hydroxyoctanoate) (PHO) as a matrix and a colloidal suspension of hydrolyzed cellulose whiskers as natural and biodegradable fillers. Due to the geometiy and aspect ratio of the cellulose whiskers, the formation of a rigid filler network, called the percolation phenomenon, was observed, leading to higher mechanical PHO properties. ... 

Proposed polysaccharide-derived materials as biodegradable fillers include a variety of starches, cellulose, lignin, sawdust, casein, mannitol, lactose, and other materials. These fillers have been tried in compositions of as much as 80% in a wide range of synthetic resins, including PE, PP, PS, ethylene-acrylic acid copolymers, PVC, and vinyl alcohol copolymers. Often additional additives such as fatty acids and processing aids are incorporated to improve the biodegradability of the finished product. Starch-based polymers are discussed further in Chapter 3 of this handbook. 

Starch was added as filler to various resin systems to make films that were impermeable to water but permeable to water vapour. Starch as a biodegradable filler in LDPE was reported (Griffin, 1973 Griffin and Turner, 1978) and disposable polyvinyl chloride (Westhoff et al, 1974). There have been contrasting reports on the mechanical properties on starch/PLA composites (Kim et al, 1998 Willett, 1998). However, a recent report confirms that the... 

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