溶膠-凝膠法製備熱塑型PU樹脂-矽氧有機-無機混成材料之研究

Abstract

In this study, alkyd resins of E-PA and E-AA were prepared by reacting ethylene glycol with phthalic anhydride and adipic acid, respectively. Both of the alkyd resins and PEG were used as raw materials of two functionality polyol to react with the two functionality isocyanate, such as HDI, TDI and IPDI, to prepare the thermoplastic polyurethane resin (PU resin). On the other hand, the rice husk was liquefied in polyethylene glycol/glycerol co-solvent with H2SO4 as catalyst, and the liquefied rice husk was blended with the isocyanate of Desmodur N to prepare another PU resin. All of the PU resins were mixed with the monomer of tetraethoxysilane (TEOS) to undergo the sol-gel process under acid condition to form an organic-inorganic hybrid. The effects of the kind of PU resin and the ratio of TEOS added on the basic properties, structure characteristic and thermal properties of PU-Silica hybrids were investigated. The result showed that the aromatic TDI had the highest reactivity than the others. Whereas, the aliphatic HDI had a lower reactivity and the alicyclic IPDI had the lowest reactivity. Both the thermoplastic PU resins of EPA-HDI and EPA-TDI had a well film-forming capability. The FT-IR analysis showed that the degraded components of rice husk reacted with the liquefaction agent to form derivatives by etherification. The inorganic network structure in the PU-Silica hybrid which formed from TEOS by sol-gel process was predominated with Si-O-Si and Si-OH. The solvent resistance of thermoplastic PU-Silica hybrids would be enhanced as the content of TEOS added for the preparation of hybrids increased. The hybrids of PU-Silica based on liquefied rice husk had good solvent resistance. DSC thermo-analysis showed that the room-temperature cured PU resins would undergo a further cross-linking reaction as heating to a higher temperature. TGA analysis showed that the three-dimensional net structure of silica in the hybrids could restrict the thermal motion of organic polymer, and retarded the rate of thermo-degradation. The residue after high temperature heating would increase as the content of inorganic silica increased in the hybrids.