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Thermal crosslinking of cis ‐1,4‐polybutadiene at ultrahigh pressures
Author(s) -
Zeng XingRong,
Ko TzeMan
Publication year - 1998
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/(sici)1097-4628(19980328)67:13<2131::aid-app3>3.0.co;2-f
Subject(s) - crystallinity , polybutadiene , annealing (glass) , differential scanning calorimetry , glass transition , materials science , fourier transform infrared spectroscopy , polymer chemistry , composite material , analytical chemistry (journal) , polymer , chemical engineering , chemistry , copolymer , organic chemistry , thermodynamics , physics , engineering
cis ‐1,4‐Polybutadiene (BR) samples, in the absence of crosslinking agents, were simultaneously compressed by ultrahigh pressures (>4.0 GPa) and annealed between 25 and 180°C. The BR samples were crosslinked when the annealing temperatures were above 100°C. The Vickers microhardness of the treated BR increased and the extent of swelling decreased rapidly as the annealing temperature increased, indicating that the crosslinking density increased. Solid‐state carbon‐13 nuclear magnetic resonance and Fourier transform infrared spectroscopy results showed that some C=C bonds in the BR were opened to form the crosslinking network structures with C—C linkages and that a partial cis–trans isomerization took place during the treatments. Differential scanning calorimetry studies revealed that the glass transition temperature increased and the crystallinity decreased as the annealing temperature increased. When the annealing temperature exceeded 140°C, the treated BR samples lost their rubbery elastic characteristics completely and became brittle materials. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2131–2140, 1998