Preparation of hybrid polyurethane–silica composites by a lateral sol-gel process using tetraethyl orthosilicate. (January 2018)

• Record Type: Journal Article
• Authors: Chung, Yong-Chan; Chung, Kyung Hoon; Choi, Jae Won; Chun, Byoung Chul
• Is Part Of: Journal of composite materials. Volume 52:Number 2(2018)
• Page Start: 159
• Page End: 168
• Publication Date: 2018-01
• Subjects: Sol-gel -- polyurethane -- cross-linking -- shape recovery; Composite materials -- Periodicals; Composites -- Périodiques; 620.118
• DOI: 10.1177/0021998317704279
• Languages: English
• ISSNs: 0021-9983

Abstract

Hybrid polyurethane–silica composites were prepared using a sol-gel reaction between tetraethyl orthosilicate and triethoxysilyl groups grafted onto polyurethane. The TS series contained the same polyurethane composition but the tetraethyl orthosilicate content varied. Soft segment Tm and Tg values were not affected by the tetraethyl orthosilicate content, while ΔH for soft segment melting and crystallization increased with the tetraethyl orthosilicate content. The tensile strength sharply increased from the cross-linking of the grafted silica at low tetraethyl orthosilicate concentrations but decreased with the increase of tetraethyl orthosilicate content because excess silica inhibited cross-linking. The shape recovery of the TS series improved during cyclic tests, and shape retention slightly decreased as the test cycles repeated. Low temperature flexibility moderately improved with the formation of grafted silica. Therefore, the grafted sol-gel silica formation demonstrated a tensile strength improvement and reproducible shape recovery.