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Tensile yield in poly(chlorotrifluoroethylene) and poly(vinylidene fluoride)
Author(s) -
Hartmann Bruce,
Lee Gilbert F.
Publication year - 1991
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.760310405
Subject(s) - materials science , chlorotrifluoroethylene , composite material , polymer , yield (engineering) , crystallinity , melting point , amorphous solid , glass transition , ultimate tensile strength , elastic modulus , crystallography , chemistry , tetrafluoroethylene , copolymer
Uniaxial tension tests to the yield point were performed on poly(chlorotrifluoroethylene) (PCTFE) and poly(vinylidene fluoride) (PVF2) from room temperature to near the melting point at a strain rate of 2 min −1 . At room temperature and at least two elevated temperatures, measurements were also made at strain rates from 0.02 to 8 min −1 . The properties of these polymers were found to be similar to those of other semicrystalline polymers. In the absence of other transitions, yield energy was found to be a linear function of temperature extrapolating to zero near the melting temperature. The ratio of thermal to mechanical energy to produce yielding is smaller than for glassy polymers. Yield stress is a linear function of log strain rate. The ratio of yield stress to (initial) Young's modulus is about 0.03 at room temperature for both polymers. Yield stress is a linear function of unstrained volume. Yield strain, elastic, and plastic strain all initially increase with temperature, but PCTFE shows a decrease with temperature starting at about 100°C, thus behaving like a glassy amorphous polymer in this region.