不同合成法酚醛樹脂製作碳材料之孔隙特性

Pore characteristics of carbon material prepared form phenolformaldehyde resin synthesized with different methods

酚醛樹脂（Phenol-formaldehyde resin；PF）為最重要的合成樹脂之一，除了做為膠合劑、含浸樹脂及成型材料使用外，透過高溫熱處理可獲得高收率的多孔性碳材料。本研究以酚及福馬林為原料，利用懸浮聚合法（Suspension polymerization；PF-A）、相反轉乳化聚合法（Inverse emulsion polymerization；PF-B）及原位聚合法（In situ polymerization；PF-C）製作硬化PF樹脂，其中PF-A為獨立的圓球狀樹脂，PF-B是由許多微小的圓球狀樹脂聚集而形成的粒子，PF-C則為塊狀樹脂。FTIR分析顯示PF-A之結構以四取代苯環為主，PF-B及PF-C則分別以1,2,4-及1,2,6-三取代之苯環為主。TGA結果顯示PF-A及PF-C有較佳的熱抵抗性，加熱至750℃之焦炭率在65％以上，而PF-B之熱抵抗性則偏低。三種PF樹脂經碳化處理後可大幅提高其吸附能力，其中以PF-C有最發達的孔隙結構及最大的吸附能力，其碳化材內部同時具備微孔及中孔，比表面積419.6m2／g，等溫吸脫附曲線則屬於IUPAC（International Union of Pure and Applied Chemistry）分類之Type Ⅳ（a）。

Phenol-formaldehyde resin (PF) is one of the most important synthetic resins. In addition to being used as an adhesive, impregnated resins and molding materials, porous carbon can be obtained from PF resin through a high-temperature heat treatment with high yield. In this study, phenol and formalin were used as raw materials to prepare hardened PF resins by suspension polymerization (PF-A), inverse emulsion polymerization (PF-B) and in situ polymerization (PF-C). Among them, PF-A was an independent spherical resin, PF-B was a particle formed by the aggregation of many tiny spherical resins, and PF-C is a bulk resin. FTIR analysis showed that the structure of PF-A was dominated by tetra-substituted benzene rings, while PF-B and PF-C were dominated by 1,2,4- and 1,2,6-trisubstituted benzene rings. TGA results showed that PF-A and PF-C had better thermal resistance. They had a char yield of more than 65% when heated to 750℃, while the thermal resistance of PF-B is low. After carbonization, the adsorption capacity of the three PF resins could be greatly improved. Among them, PF-C had the most developed pore structure and the largest adsorption capacity. Its carbonized materials had both micropores and mesopores with a specific surface area of 419.6 m2 /g, and had the nitrogen isothermal adsorption-desorption curves belonged to IUPAC (International Union of Pure and Applied Chemistry) Classification of Type IV (a).