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The influence of crystallinity on the beta‐transition in poly(vinyl chloride)
Author(s) -
Harrell E. Ray,
Chartoff Richard P.
Publication year - 1974
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.760140510
Subject(s) - crystallinity , materials science , ultimate tensile strength , vinyl chloride , glass transition , composite material , toughness , dissipation factor , relaxation (psychology) , dynamic mechanical analysis , modulus , compressive strength , polymer , psychology , social psychology , optoelectronics , dielectric , copolymer
The effect of changes in crystallinity on the β‐transition in poly(vinyl chloride) was studied by dynamic mechanical measurements of loss tangent (tan δ) and storage modulus ( E ′) over the temperature range −160° to 85°C. Four frequencies were covered, 3.5, 11, 35, and 110 Hz. The data presented demonstrate that crystallinity has a significant influence on the relaxation processes involved in the β‐transition. The restrictions on segmental mobility imposed by crystallinity are most pronounced in the region between T β and T g , with T β tending to shift to lower temperatures, T g shifting to slightly higher temperatures, the magnitude of tan δ decreasing, and engineering tensile strength increasing. Our data also show that individual PVC resins have mechanical and physical properties which differ enough so that comparisons which are often made between them may be inconclusive. Moreover, the properties of one resin may be more sensitive to thermal treatment than those of another. We are continuing this study to establish correlations between the observed trends and other important mechanical properties such as impact strength, toughness, tensile, and compressive strength.