PVAc－Silica－竹炭粉混成材料之製備及其性質

Preparation and Properties of PVAc-Silica-Bamboo Char Powder Hybrids

本研究將四乙基矽氧烷（Tetraethoxysilane；TEOS）之預聚物與溶劑型聚醋酸乙烯樹脂（polyvinyl acetate；PVAc）及竹炭粉混合，其中TEOS藉由溶膠-凝膠反應（Sol-gel reaction）形成矽氧（Silica）網狀結構，並與PVAc及竹炭粉混成，形成同時具備有機與無機特性之PVAc／Silica／竹炭粉混成材料（Hybrid）。由試驗結果得知，PVAc／TEOS預聚合物混成溶液可於常溫下進行溶膠-凝膠反應形成PVAc／Silica有機與無機混成材料，並提升PVAc之耐水性能。PVAc／Silica／竹炭粉混成材料製作時，先將PVAc／TEOS預聚物攪拌1hr，並經3hr靜置後再加入竹炭粉可獲得較佳之成膜性，浸水試驗顯示竹炭粉可固定於混成薄膜中而不被析出，乙酸乙酯溶出試驗則顯示較高之重量保留率，然添加竹炭粉將降低PVAc／Silica混成材料之耐水性及機械強度，DSC熱分析則顯示其吸熱峰溫度向低溫側偏移。PVAc／Silica及PVAc／Silica／竹炭粉混成材料薄膜製作時以常溫乾燥硬化者其性能優於加熱硬化者，且成膜3週後可達最佳之薄膜機械強度。 In this research, the tetraethoxysilane (TEOS) prepolymer, solvent type polyvinyl acetate (PVAc) and bamboo char powder were mixed. The TEOS would undergo sol-gel reaction to form a silica network structure and blending with PVAc and bamboo char powder to form a PVAc/silica/bamboo char powder hybrids those had both the organic and inorganic characteristics simultaneously. The results showed that PVAc/TEOS prepolymer solution could undergo the sol-gel reaction at room temperature to form an organic-inorganic hybrid and improve the water resistance of PVAc. For the PVAc/silica/bamboo char powder hybrids preparation, the bamboo char powder added after the mixture of PVAc solution and TEOS prepolymer was stirring for 1 hr and standing for 3 hr had the better effect of film-forming. The water immersing test showed that bamboo char powder could be fixed in the hybrid films and would not be separated out. The ethyl acetate dissolving test shown PVAc/silica/bamboo char powder hybrids had high weight retention. However, adding bamboo char powder into the PVAc/Silica hybrids would decrease the water resistance and mechanical strength. DSC thermal analysis shown the temperature of endothermic peak shifted to lower temperature. Both the PVAc/Silica and PVAc/Silica/bamboo char powder hybrids made under room temperature had the performances better than those of heating treatment. The best mechanical strength of the hybrids would be achieved at three weeks after the film formation.

In this research, the tetraethoxysilane (TEOS) prepolymer, solvent type polyvinyl acetate (PVAc) and bamboo char powder were mixed. The TEOS would undergo sol-gel reaction to form a silica network structure and blending with PVAc and bamboo char powder to form a PVAc/silica/bamboo char powder hybrids those had both the organic and inorganic characteristics simultaneously. The results showed that PVAc/TEOS prepolymer solution could undergo the sol-gel reaction at room temperature to form an organic-inorganic hybrid and improve the water resistance of PVAc. For the PVAc/silica/bamboo char powder hybrids preparation, the bamboo char powder added after the mixture of PVAc solution and TEOS prepolymer was stirring for 1 hr and standing for 3 hr had the better effect of film-forming. The water immersing test showed that bamboo char powder could be fixed in the hybrid films and would not be separated out. The ethyl acetate dissolving test shown PVAc/silica/bamboo char powder hybrids had high weight retention. However, adding bamboo char powder into the PVAc/Silica hybrids would decrease the water resistance and mechanical strength. DSC thermal analysis shown the temperature of endothermic peak shifted to lower temperature. Both the PVAc/Silica and PVAc/Silica/bamboo char powder hybrids made under room temperature had the performances better than those of heating treatment. The best mechanical strength of the hybrids would be achieved at three weeks after the film formation.