Inorganic-Organic Polymers as Migration Barriers Against Liquid and Volatile Compounds

Abstract

In addition to the barrier properties against water vapor and oxygen, inorganic-organic polymers can also function as protection layers against unwanted migration of chemical substances in two ways. First, hybrid polymers prevent components from migrating out of polymer substrates. This is of special interest for polymeric materials containing substances like plasticizing agents, unreacted monomers or catalysts. Thus the olfactory nuisance and the toxicological emission are decreased. The plastics are also prevented from becoming prematurely brittle. Second, the coated materials are also protected against the interaction of dyes or dirt staining the material.

These functions can be achieved by thermally or UV curable coating materials, synthesized by the sol-gel technique. Since several polymer materials show only a low heat resistance (e.g. PVC, polyolefines), this publication is focussed on the development of new migration barriers based on photochemically curable sols.

Another advantage of the UV process in comparison to thermal treatments are the short curing times and low power consumption which make this process even more attractive for industrial applications. The coatings were characterized by IR and solid state NMR spectroscopy. The migration barrier properties were tested according to industrial standards.

Due to the choice of specific functional groups, these hybrid polymers can be further modified in order to combine the migration barrier function with additional properties: scratch and abrasion resistance, hydrophobicity, antistatic effects. Examples of feasible combinations of properties are also given.