Effects of soft monomers on the water resistance and moisture permeability of hydrophilic polyurethane

Abstract

Six groups of segmented polyurethanes with amorphous soft segment domains based on mixed hydrophobic polyester and hydrophilic polyether soft monomers were prepared from 4, 4′-diphenylmethane diisocyanate (MDI), polybutylene adipate glycol 2000 (PBA2000), polytetramethylene glycol 1000 (PTMG1000) and polyethylene glycol 1000 (PEG1000) with 1,4-butanediol (BDO) as the chain extender. Furthermore, the representative properties of the hydrophilic polyurethanes, moisture permeability and water resistance, were investigated. The results show that the chemical structure, molecular weight and concentration of soft monomers have remarkable effects on the main application properties of hydrophilic polyurethane. The important factors in diffusion are the content of hydrophilic ether bond and the mobility of hydrophilic chain in the soft phase, which is represented with a good approximation by the average mean molecular weight of soft segment. On the contrary, the functional properties of the hydrophilic polyurethane are almost not affected by its hard segment.