Anisotropic Behavior of the Thermal Diffusivity of Polymer Materials. (1st Report. Dependence of Anisotropy on Injection Conditions for Spiral-Flow Samples)

Anisotropic behavior of thermal diffusivity was experimentally studied in PMMA samples shaped in a spiral testing mold by an injection molding machine. The method used was the forced Rayleigh scattering method, a newly developed optical method. The influences of such factors as temperature of the melt, solidification process and the backpressure were quantitatively measured, and the relations among shear stress, molecular orientation and thermal anisotropy were discussed.