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Effect of catalytic aging reactions on mechanical and solubility properties of films derived from neopentyl adipate polyesters and toluene diisocyanate
Author(s) -
Cinadr Bernard F.,
Bobalek G.
Publication year - 1962
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.1962.070061904
Subject(s) - solubility , polyester , materials science , polymer , polymer chemistry , hexamethylene diisocyanate , polymerization , hildebrand solubility parameter , adipate , polyurethane , ultimate tensile strength , solvent , catalysis , chemical engineering , isophorone diisocyanate , chemistry , organic chemistry , composite material , engineering
Although the necessary conditions are known for formation of tough films from polyurethane intermediates, the chemistry is too complex to allow certain predictions of how variances in the polymerization process effect molecular structure and polymer properties. This research examined the hope that a correlated study of solubility and mechanical behaviors might show the effect of different catalysts and environments on crosslinking or other structural features which can modify film quality. Films (0.01 in. thick) were cast on mercury of intermediates derived from reaction in solvent of 2 moles of diisocyanate per mole of hydroxyl terminated polyesters, catalysts like N ‐methylmorpholine, methyldiethanolamine, and cobalt and/or lead ions being used to promote film‐forming reactions. The films, when dry, were aged at different levels of temperature and humidity. The solubility behavior was rated by measuring swelling ratios, rates of extraction, and intrinsic viscosity of extracts. Mechanical properties were rated by measuring tensile and stress relaxation behavior. The stress‐induced microstructure and fracture process were observed microscopically in a few typical specimens. The data support the theory that hydrogen bonding provides a strong crosslinking mechanism which dominates even the effects of moderate covalent crosslinking. Polymers derived from the same intermediates show very similar mechanical properties, even though significant differences in solubility properties suggest variances in other details of molecular structure.