Graft copolymers of polysaccharides with thermoplastic polymers. A new type of filled plastic

Abstract

A series of starch graft copolymers and one cellulose graft copolymer were prepared containing 40-50 percent synthetic polymer. The monomers used (styrene, methyl methacrylate, methyl acrylate, and butyl acrylate) were chosen to give grafted synthetic polymers with varying glass transition temperatures (Z,). These graft copolymers were extruded, in the absence of any added thermoplastic homopolymer, to give strong, continuous polysaccharide-filled plastics which are biodegradable and which exhibit little or no die swell. Properties of plastics varied with the T , of the thermoplastic portion. Starch-gpolystyrene and starch-g-poly(methy1 methacrylate) were hard and brittle, while graft copolymers prepared from methyl and butyl acrylate were more flexible and leathery. The graft copolymers with lower T , grafts required less torque and could be extruded at lower temperatures. In the methyl acrylate series, a graft copolymer prepared from gelatinized starch was more easily extruded than one prepared from granular starch, and addition of water produced a water-filled extrudate of excellent quality. The surprising feature of these results is that the matrix polymers, starch and cellulose, are rigid, nonsoftening materials. Grafting of a thermoplastic polymer to these matrix polymers would not be expected to give an extrudable product. The results are explained as powder flow followed by fusion or sintering of the graft polymers under the temperature and pressure conditions in the die.

Preparation and characterization of maleated thermoplastic starch‐based nanocomposites

“…Usually, the tensile strength and the modulus increase with an increase in the blend crystallinity. 26,34,35 In this case, the observed mechanical improvement was likely due to the improvement of interfacial (reactive) contact between Cloisite 30B and the surrounding matrix, leading to a nanoscale reinforcement for the blend. In addition to its moderated polarity character, such a behavior could be explained by primary hydroxyl groups from the quaternary ammonium ion present within the clay galleries of Cloisite 30B.…”

Structure and properties of starch/poly(ethylene‐co‐vinyl alcohol) blown films

“…In this study, starch/EVOH improve the mechanical properties and moisture blends plasticized with water and glycerol are proresistance of starch-based materials: graft copolycessed into blown films. The films are conditioned merization, 5,6 derivatization, 2,3,7 and blending to different moisture contents and examined by with other polymers.…”

Biodegradabilidade e propriedades mecânicas de novas misturas poliméricas

“…O recurso de se utilizar um aditivo natural degradável para as formulações de plásticos biodegradáveis não é nova. Aditivos naturais tais como o amido, a celulose, a lignina, entre outros, são usados em formulações de plásticos convencionais [6][7][8] .…”

“…Quando biodegradado ou incinerado este material libera CO 2 para a atmosfera. Estas características do amido tem despertado um interesse acentuado pelo mercado de polímeros convencionais através da sua incorporação em misturas poliméricas [6][7][8] .…”