Premium
Head to head polymers. XXV: Properties of head to head polyisobutylene
Author(s) -
Malanga Michael,
Vogl Otto
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.760231012
Subject(s) - head (geology) , materials science , melting point , polymer , glass transition , polymer chemistry , diffraction , composite material , optics , physics , geomorphology , geology
Head‐to‐head polyisobutylene, prepared by the Grignard coupling reaction of 2,2,3,3‐tetramethyl‐1,4‐dibromobutane had molecular weight of 3,000 to 10,000 and was characterized by wide angle x‐ray diffraction, optical microscopy and thermal behavior. Head‐to‐head polyisobutylene is crystalline, with a crystalline melting point of 187°C and a glass transition temperature of 87°C (measured by DSC at a scan rate of 20°/min.); these values compare to a glass transition temperature of head‐to‐tail polyisobutylene of similar molecular weight of −61°C and a crystalline melting point of 5°C, which can only be observed when the sample was stretched. The maximum rate of degradation of head‐to‐head polyisobutylene (20°/min. programmed temperature increase) is at 315°C, 70°C lower than that of head‐to‐tail polyisobutylene.