Blending PHAs and in particular PHB with other polymers, or with plasticizers, may offer opportuni- ties to improve processability by lowering the pro- cessing temperature and reducing the brittleness of PHAs based plastics. So far many blends containing PHB/PHAs have been studied and also many types of plasticizers have been proposed ([37, 38]).The literature reports the use as plasticizers from materials that are cheap and readily available on the market, and generally also of natural origin, such as oxypropylated glycerin (or laprol), glycerol, glycerol triacetate, 4-nonylphenol, 4,40-dihydroxydiphenyl- methane, acetyl tributyl citrate, salicylic ester, acetyl- salicylic acid ester, soybean oil, epoxidized soy- bean oil, dibutyl phthalate, triethyl citrate, dioctyl phthalate, dioctyl sebacate, acetyl tributyl citrate, di-2-ethylhexylphthalate, tri(ethylene glycol)-bis(2- ethylhexanoate), triacetine, and fatty alcohols with or without glycerol fatty esters, polyethylene glycol (PEG) as well as low molecular weight polyhydrox- ybutyrate since PHAs with medium chain length are elastomers with low melting point and a rela- tively lower degree of crystallinity ([39, 40]).
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