A study of factors influencing the yield of products resulting from the addition of nitric acid to ethylene oxide (oxirane) compounds has been made. For reactions in aqueous solutions, it was demonstrated that the ratio of nitrated products to side products was directly proportional to the ratio of nitrate ion (in moles per liter) to water (in moles per liter) at a given temperature. An increase in temperature increased the yield of nitrated product. Several new nitrato alcohols have been prepared in good yield by two nitration procedures. In addition, information relating to positional isomerism, heats of reaction, and major side reactions is included.
A study was made of the mechanical and equilibrium swelling properties of five series of polyurethane elastomers prepared from polyoxypropylene glycol 2025, dipropylene glycol, trimethylol propane, and either toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI). The study included the dependence of the properties on the ratio of isocyanate to hydroxyl groups, the concentration of urethane groups, [U], and the triol concentration; the triol concentration and [U] were varied independently in four series of elastomers. It was found that the glass transition temperature for both the TDI elastomers and HDI elastomers increased linearly with [U]. For elastomers having a constant [U], the quasi‐equilibrium elongation at a given value of T − Tg increased linearly with the reciprocal of the number of effective chains per unit volume, but the tensile strength depended only slightly on this quantity. For elastomers having the same triol concentration, the ultimate properties over a wide temperature range were compared at equal values of T − Tg and were found to depend on [U], especially for elastomers having the largest [U]‐values. Several factors that might contribute to this behavior are considered. No major differences between TDI and HDI elastomers were observed except in Tg values. The equilibrium swelling ratios in benzene were used along with equilibrium modulus data to calculate the polymer–solvent interaction parameter χ1. This parameter was found to be independent of crosslinking density, but it increased with [U] and was slightly less for the HDI elastomers than for the TDI elastomers.
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 − Tg,. 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 − Tg, 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 ve½ and 1/ve, 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.
Thermophtic, l i b t a b l e polyurethanes have been prepared by the interfacial polycondensation of secondary diamines with the bischloroformates of polyester diols derived from ecaprolactones. A straighbline relationship was obtained from a logarithmic plot of inherent viscosity versus &. The effect of some structural variations on the properties of the polyurethanes is discussed. These variations included the molecular weight of the polyester diol, the initiator used in preparing the polyester diol, the introduction of a methyl substituent on the caprolactone ring, and the structure of the diamine. Polyurethanes prepared from polyester diols of an from 2000-4000 are opaque, stiff materials which undergo a melting transition a t 40-50'C. characteristic of the polyester component. Polyurethanes which are flexible and translucent a t room temperature are obtained either by using a low molecular weight polyester diol or a copolyester diol containing >25% methyl e-caprolactone. The polyurethanes described are soluble in several common solvents and can be cold-drawn to produce material of high tensile strength. Thermal studies using DTA and TGA show an exothermic reaction starting above 300°C. Rapid weight loss beginning at 300330°C. and leveling off near 500°C. accounted for 85-90% of the total sample and is attributed to decomposition of the polyester chains.
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