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Effects of strain rate and temperature upon tensile properties of acetal copolymers
Author(s) -
Wissbrun K. F.
Publication year - 1983
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760230410
Subject(s) - elongation , materials science , extrapolation , polymer , ultimate tensile strength , copolymer , amorphous solid , time–temperature superposition , yield (engineering) , superposition principle , composite material , creep , thermodynamics , polymer chemistry , crystallography , mathematics , chemistry , physics , statistics , mathematical analysis
The strength and elongation to break of an acetal copolymer were measured at four elongation rates, from 0.2 to 20 in./min, at temperatures from 239 K to 339 K. Both strength and elongation results could be reduced to master curves by means of time‐temperature superposition. The temperature dependence of the shift factors was given by an equation of the WLF form, with parameters close to those found for most amorphous polymers, at a reference temperature equal to the γ‐transition temperature of the polymer. Extrapolation to much higher testing rates and to much slower creep rates was satisfactory. Similar but less extensive tests were run on two other samples with different molecular weights. The yield stress was independent of molecular weight, but elongation increased with increasing molecular weight at all conditions.