Stress-Strain Relationships in Hydroxyl Substituted Polyethylene.

Abstract

Stress-strain relationships in semicrystalline hydroxylated polyethylene are studied using all-atom molecular dynamics simulations. Chain sizes ranging from 50 to 2000 carbons are gradually cooled from melt in order to obtain semicrystalline samples for pure, 4%, and 8% hydroxylated chains. Local orientational order of the polymer backbone and hydrogen bonding behavior is studied. The effects of -OH substitution and chain length on stress-strain relationships are examined at 300 K. The number of hydrogen bonds is found to be independent of the chain length. Stress-strain relationships are generally unaffected by 4% hydroxyl substitution in long chain polyethylene. The presence of 8% -OH tends to increase the elastic limit of the material. A method for comparing semicrystalline samples of substituted and unsubstituted polymeric chains is presented by eliminating differences in alignment, distribution, and extent of crystallization.