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Diisocyanate‐linked polymers. III. Relationships between the composition and ultimate tensile properties of some polyurethane elastomers
Author(s) -
Smith Thor L.,
Magnusson Alan B.
Publication year - 1961
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.1961.070051415
Subject(s) - elastomer , toluene diisocyanate , materials science , ultimate tensile strength , polyester , polyurethane , diol , polymer chemistry , ethylene glycol , hexamethylene diisocyanate , polymer , elongation , composite material , chemistry , organic chemistry
The ultimate tensile properties (tensile strength and elongation at rupture) of various series of polyurethane elastomers which apparently do not crystallize were studied. Elastomers which contained 0–20% isodecyl pelargonate were prepared from polyoxypropylene glycol 2025 (PPG), dipropylene glycol (DPG), trimethylolpropane (TMP), and toluene 2,4‐diisocyanate (TDI); the ratios of ingredients were varied so that all clastomers had approximately the same number of chains per unit volume v and tho same concentration of urethane groups [U]. Unplasticized elastomers were also prepared that were similar except that they were linked by hexamethylene 1,6‐diisocyanate, TDI, m ‐phenylene diisocyanate, and naphthalene 1,5‐diisocyanate. Over a wide temperature range, the ultimate proper‐ ties of elastomers in both series were identical at equal values of T − T g ,. Series of elastomers were also preparcd from TMP, TDI, triethylme glycol, and two polyester diols: a 50/50 and an 80/20 copolymer of ε‐caprolactone and methyl ε‐caprolactone. In these series, v was held constant and [U] was varied. Within each series, the ultimate properties were identical at equal values of T − T g , although the ultimate properties depended on the nature of the polyester diol and were different from those of similar elastomers prepared from PPG. To study the effect of the crosslinker type and the concentration, elastomers having a constant [U] were prepared from PPG, DPG, TUI, and six crosslinkers, three being trihydroxy and three being tetrahydroxy materials. At a given temperature, the tensile strength and ultimate elongation appeared to be inde‐ pendent of the crosslinker type and proportional to v e ½ and 1/ v e , respectively, the proportionality constants being temperature‐dependent. On these elastomers, equilibrium swelling ratios in benzene and rough values of the per cent sol were also measured and certain relations among these and the mechanical properties were observed.