本研究係運用本體聚合法聚合聚甲基丙烯酸甲酯(PMMA),並添加天然石墨(NG)和膨脹石墨(EG)為填充材,在改變石墨種類(3μm、40μm、NG及EG)及添加量後製成PMMA與石墨之複合材料。本實驗先以硫酸、過氧化氫及硝酸將天然石墨進行酸化插層處理後,將此之石墨以750℃高溫膨化後,將所製備之石墨以及天然石墨分別添加至PMMA本體聚合實驗中,最後以熱壓成型法製得不同含量之PMMA與石墨複合材料。 測試方面,先以ATR-FTIR對PMMA/石墨複材做表面特徵官能基分析,發現添加不同石墨粉體(NG、EG)並未出現新的官能基特性峰或是造成偏移現象,代表本研究屬於物理混掺,後續運用熱重量分析儀(TGA)探討PMMA與石墨複合材料之熱性質;另外運用迅速導熱係數測定儀及導熱性評估測試來探討PMMA/石墨複材之導熱性能,實驗中發現添加小粒徑石墨有助於增加材料之導熱性質,且石墨經膨脹處理後,相較於天然石墨更能提升基材之導熱性;以掃描式電子顯微鏡(SEM)來觀測膨脹石墨之型態及石墨粉體在PMMA與石墨複材中之分散情形,最後顧及該複材之耐用性,故亦探討其壓縮及彎曲之機械性質。
In this study, the submicron natural graphite (NG) and expanded graphite (EG) powders were added during the process of PMMA (Poly(Methyl Methacrylate)) in-situ polymerization to fabricate composites. In this experiment, the natural graphite powder was mixed and saturated with acids consisting of concentrated sulfuric acid, hydrogen peroxide and nitric acid to form the graphite intercalated compound (GIC). The mixed acid was an intercalant. The mixture was carefully washed and filtrated with deionized water until the pH level of the solution reached 6. After being dried at 60 ℃in a vacuum oven for 12 h, the GIC was rapidly expanded at 750 ℃ in a muffle furnace to form expanded graphite (EG). Then, it was in the course of synthesizing methyl methacrylate to form PMMA, the submicron natural graphite (NG) and expanded graphite (EG) powders with different particle sizes (3μm and 40μm) and amounts were added. To understand the composite properties, PMMA/ graphite composites were investigated by ATR-FTIR, which shows neither new groups were made nor phenomenon of displacement. The basic thermal properties of PMMA and graphite composites were investigated by thermogravimetric analyzer (TGA) and the thermal conductivity were evaluated by quick thermal conductivity meter. To consider the endurance of composites, the mechanical properties were also investigated. The dispersibility of filler in PMMA and graphite composites was obtained by studying the scanning electron microscopy (SEM).