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Radiation‐crosslinked polypropylene: Physical and dielectric properties
Author(s) -
Benderly Asaf A.,
Bernstein Bruce S.
Publication year - 1969
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1969.070130311
Subject(s) - materials science , irradiation , dielectric , creep , monomer , polypropylene , composite material , ultimate tensile strength , dielectric loss , polymer chemistry , dielectric strength , methacrylate , dissipation factor , polymer , physics , optoelectronics , nuclear physics
Irradiation of two stereoregular polypropylenes and a polyallomer via 60 Co in the presence of 3–8% allyl methacrylate (AMA) monomer, to does up to 5 Mrad, lead to an improvement in mechanical properties. With irradiation, heat resistance, tensile strength, and gel fractions increased, and creep compliance decreased. The decrease in creep compliance was revealed by measurements of irradiated samples at 185 0 C (at constant load and monomer level), a temperature above the T m of polypropylene. Dielectric properties (dielectric constant K and dissipation factor tan δ) were virtually unaffected by irradiation of 0.3 to 5.0 Mrad in nitrogen when AMA was absent. In the presence of monomer, small but generally tolerable increases in tan δ resulted if the monomer concentration was not too great. To obtain improvements in mechanical properties while not simultaneously altering the dielectric losses, it was necessary to keep the AMA concentration to a maximum of 4%.