Abstract: A photo-degradable synthetic resin composition which consists of a blend of a butadiene-containing graft copolymer and a thermoplastic resin. The blend consists essentially of (A) 50-99 parts by weight of a graft copolymer containing at least 30% by weight of butadiene monomer, said copolymer being composed of 40-80 parts by weight of butadiene or a copolymer thereof, 60-20 parts by weight of styrene, methyl methacrylate or a mixture thereof and 0.01-5 parts by weight of a cross-linking agent copolymerizable therewith, and (B) 1-50 parts by weight of polystyrene, polymethyl methacrylate, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride or copolymers thereof.

Abstract: A highly piezoelectric polyvinylidene fluoride element is prepared by treating a polyvinylidene fluoride film having an infrared absorbance ratio D.sub.530 /D.sub.510 of not more than 1.2, namely having a major proportion of .beta.-type crystal structure, at a temperature of at least 40.degree.C but below the melting point of the film while applying to the film a direct current voltage of 200 KV/cm to 1,500 KV/cm. The polyvinylidene fluoride film having a major proportion of .beta.-type crystal structure may be obtained by stretching a fabricated article of polyvinylidene fluoride having a major proportion of .alpha.-type crystal structure under specific conditions.