Effect of Chain Architecture and Conformation on the Features of the Statistical Strength Distributions of Oriented Polymer Materials

Abstract

In this paper, we analyze a large dataset (300 measurements) on the statistical distribution of σ strength values of oriented samples of ultrahigh-molecular-weight polyethylene (UHMWPE), nylon-6 (PA-6), and polypropylene (PP) using the Weibull model. By varying the chain conformation (in-plane trans-zigzag in UHMWPE and PA-6 and helical conformation in PP), draw ratio λ (from λ = 10 for PA-6 and PP to λ = 120 for UHMWPE), and the sample type (monofilament and multifilament), it is possible to analyze the tensile strengths in a wide range of values, from 0.2 GPa (PP) to 6 GPa (UHMWPE), i.e., at their significant, 30-fold difference. The Weibull model, which was previously proposed to describe the statistical distributions of σ in brittle high-strength inorganic materials (glass and quartz fibers, etc.), is shown to be useful to correctly describe the statistical distributions of σ in all studied oriented polymer monofilament and multifilament fibers when processing a large dataset (at least 50 parallel measurements for each studied material). The identity of the regularities of statistical distributions of σ according to Weibull is revealed for quasi-brittle high-molecular-weight polymer and brittle inorganic materials (according to published data). This may indicate a single fracture mechanism of high-strength materials of varying nature.