Crystalline transitions and the solid-state extrusion of polymers



Extrusion experiments on eight polymers in our laboratory and eight additional polymers in other laboratories reveal that solid-state extrusion and malleability occur in semicrystalline polymers that have a reversible crystalline transition, Tc, and do not occur in crystalline polymers devoid of Tc, The solid-state extrusion takes place only in the temperature range of TcT < Tm. The transparency of the solid-state extrudates was shown to be largely due to void disappearance and may be due in part to the diminution in size of the scattering species. Increases in Tm were shown not to be correlatable with lamellar thickening or chain extension.