Barrier, Moisture

Name:
Barrier, Moisture
Detailed information:
Any substance that is impervious to water or water vapor. Most effective are high-polymer materials such as vulcanized rubber, phenolformaldehyde resins, polyvinyl chloride, and polyethylene, which are widely used as packaging films. The chief factors involved are polarity, crystallinity, and degree of cross-linking. Water-soluble surfactants and protective colloids increase the susceptibility of a film to water penetration. Any pigments and fillers must be completely wetted by the polymer. Properly formulated paints are effective moisture barriers.