Viscoelastic properties of single crystal mats of some polymers and polymer crystal obtained by radiation‐induced solid‐state polymerization

Measurements of the tensile dynamic viscoelasticity have been made in the temperature range from −170°C. to near the melting temperature at 110 cps on the single crystal mats of linear polyethylene with different lamella thickness and trans-1,4-polybutadiene, and the polymer crystal of polytetraoxane prepared by the radiationinduced solid-state polymerization of tetraoxane. Under the conditions of measurements, the stress applied is almost perpendicular to the molecular axis for the single crystal mat and parallel to the molecular axis for the polytetraoxane crystal. The crystalline absorption of the single crystal mat of linear polyethylene shifted to the high temperature side and increased its intensity with increasing lamella thickness. The single crystal mat of trans-1,4-polybutadiene showed the comparatively large primary absorption, which was almost eliminated by heat treatment. This phenomenon may be caused by the existence of loose loops in the sample of single crystal. Various absorptions of polyoxymethylene such as the crystalline and the low temperature secondary absorption, which was remarkable in the single crystal mat, almost completely vanished for the polytetraoxane crystal, and outstanding constancy of the dynamic modulus was attained close to the melting temperature 190°C.