Synthesis of organic/inorganic hybrid materials for coating applications

Abstract

Siloxyl group functionalized copolymer of low molecular weight was synthesized, aiming at preparing transparent inorganic/organic coating composite. Two types of coating systems; two component sytem (based on functionalized copolymer-HMMM) and three component systems (based on functionalized copolymer-HMMM-TEOS) were investigated. Their surface performance was compared. Coating films obtained from both systems exhibited good optical clarity. The results indicated that the optical clarity of coating films was largely dependent on the amounts of the inorganic contents. In the case of three component system, it was necessary that the TEOS component should be effectively linked to the organic component through pendent siloxyl groups to prevent phase seperation. Hence, the coating formula containing a functionalized copolymer of high degree of pendent siloxyl group showed better optical transparency. Abrasion/scratch resistance properties of coated/cured PC sheets were greatly improved when compared to uncoated one. Two crosslink networks; organic network resulting from transetherification between copolymer hydroxyl group and HMMM methylol group, and inorganic network resulting from sol-gel reaction were responsible for the hardening effect of coating films. Finding results also revealed that the inorganic network mainly contributed to improved surface performance of coated PC samples