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Direct Measurement of the Temperature Dependence of the Unperturbed Dimensions of a Polymer

1991; Institute of Physics; Volume: 15; Issue: 7 Linguagem: Inglês

10.1209/0295-5075/15/7/004

1286-4854

A. T Bootheroyd, Adrian R. Rennie, C. B. Boothroyd,

Advanced Physical and Chemical Molecular Interactions

We demonstrate for the first time that small-angle neutron scattering can be used as a direct and accurate method to determine the temperature dependence of the unperturbed dimensions of a polymer. The sensitivity of the technique arises from the remarkable accuracy with which the random walk model can be used to describe the single-chain structure factor, and enables us to detect changes in the polymer radius of gyration of less than 0.5%. We present results for molten polyethylene and verify the accepted value of the temperature coefficient of thermal expansion.