Properties of polyethylene modified with phosphonate side groups. III. Hydration characteristics and water permeability
The degree of hydration and the water permeability of polyethylene films were enhanced by incorporation of phosphonate pendent groups along the polymer chain. Two different phosphonate esters were considered: the dimethyl ester and an ester derived from poly(ethylene oxide) oligomers (PEO). The highest molecular weight PEO derivatives had the greatest effect on hydration and permeability. A physical change was observed during hydration for the phosphonated materials with a degree of substitution greater than 4.5. The polymers became stiff and brittle, and this was accompanied by an increase in the crystalline melting point and a remarkable change in the dynamic mechanical behavior.