Premium
Study of polypropylene annealed at a temperature near its melting point
Author(s) -
Turley S. G.,
Keskkula Henno
Publication year - 1965
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.1965.070090806
Subject(s) - polypropylene , crystallinity , materials science , composite material , melting point , annealing (glass) , torsion pendulum clock , silicone oil , melting temperature , crystallite , silicone , metallurgy , physics , quantum mechanics
Dynamic mechanical properties as determined by a torsion pendulum were used to study the effect on the crystalline structure of polypropylene of annealing at a temperature very near to its melting point. Crystallinity values as determined by both x‐ray techniques and density measurements were reported for the specimens used in this study. Differential thermal analysis was used to show the differences in melting behavior of annealed and unannealed polypropylene. It was found that, although crystallinity may increase slightly, the major effect of annealing polypropylene is an increase in the size and/or perfection of the resulting crystallites. A damping peak not normally found for polypropylene was present at −50°C. in the damping curves for those specimens annealed in silicone oil without protective wrappings. This peak was found to be due to the freezing of the absorbed silicone oil, present in the specimen as small droplets.