Ultradrawing of high‐molecular‐weight polyethylene cast from solution. II. Influence of initial polymer concentration

Abstract

Abstract Ultradrawing of films of high‐molecular‐weight polyethylene (M̄ w = 1.5 × 10 6 ) produced by gelation crystallization from solution is discussed. The influence of the initial polymer volume fraction (ϕ) on the maximum draw ratio (λ max ) of the dried films is examined in the temperature region from 90–130°C. The results can be described very well by the relation λ max = λ ϕ −1/2 where λ is the (temperature‐dependent) maximum draw ratio of the melt‐crystallized film. An attempt is made to discuss the marked influence of the initial polymer volume fraction on λ max in terms of the deformation of a network with entanglements acting as semipermanent crosslinks.