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Effects of number‐average molecular weight of network chain on physical properties of cis‐polybutadiene‐containing polyurethane
Author(s) -
Chen Teng Ko,
Hwung Chii Jen,
Hou Chih Cheng
Publication year - 1992
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.760320207
Subject(s) - polybutadiene , isophorone diisocyanate , materials science , elastomer , ultimate tensile strength , hydroxyl terminated polybutadiene , propane , composite material , modulus , polyurethane , viscometer , polymer chemistry , viscosity , polymer , copolymer , organic chemistry , chemistry
Liquid hydroxyl‐terminated cis‐polybutadiene (cis‐HTPB) having various molecular weights were cured with trimethylol propane (TMP) and isophorone diisocyanate (IPDI) by the one‐shot method and the physical properties of these elastomers obtained were measured. The effect of pseudo‐crosslinks was not observable and the calculated value of the number average molecular weight of the network chain ( M c) between each TMP crosslink unit was found to be pertinent in determining the tensile strength, modulus, tear strength, and hardness. The mechanical properties increased with increase in the 1/ M c value and showed a linear relationship with the high 1/ M c values ( M c below about 3000). On the other hand, chain entanglement becomes more important in affecting the mechanical properties when M c was higher than 3000, and physical properties were less dependent on 1/ M c values in the lower range.