Blends of natural rubber and polyurethane latices studied by 1H wideline and 13C MAS solid‐state NMR

Abstract

Abstract1H wideline and 13C magic‐angle spinning NMR have been used to study the morphology and dynamics of latex‐cast and solution‐cast film blends of natural rubber (NR) and a polyurethane (PU) based on poly(ϵ‐caprolactone) diol and isophorone di‐isocyanate. 1H T1 and T1ρ relaxation times have been measured, and the extent of interpenetration of the NR and PU constituents has been monitored using the Goldman–Shen technique. The NMR spectra and relaxation properties indicated that the NR and PI constituents largely occupy separated domains on a distance scale of >10 nm. The Goldman–Shen experiments indicated that there was slightly greater contact between NR and PU in the solution‐cast samples than in the latex‐cast. The tensile properties of the films have been measured. The tensile strength and initial Young's modulus pass through a maximum at a PU content of about 50 wt%.© 2002 Society of Chemical Industry