Abstract
Small-angle neutron scattering was used to measure the influence of temperature on the radius of gyration in the melt of atactic polypropylene and poly(l-butene). The chain dimension temperature coefficient, d In (R2)o/dT, was found to be respectively −0.1 × 10−3 and 0.4 × 10−3 deg−1. These values, with one exception, disagree with the rotational isomeric state predictions as well as with those values obtained via intrinsic viscosity measurements either at θ conditions or in perceived athermal solvents. Conversely, excellent agreement was obtained with the values available from both thermoelastic and rheological measurements on atactic poly(1-butene). © 1992, American Chemical Society. All rights reserved.