本研究以三種單體4,4′-Oxydianiline (ODA)、3,3''-Dihydroxybenzidine (HAB)、Pyromellitic dianhydride (PMDA)合成聚醯亞胺酸(Polyamic acid, PAA)預聚物,在加入3-Isocyanatopropyl triethoxysilane (IPS)與PAA中HAB的-OH官能基反應鍵結,得到改質的PAA-IPS預聚物,再將導熱無機填充料碳管、氮化硼加入,以加熱法脫水醯亞胺化,製備出碳管/氮化硼/聚醯亞胺複合材料。對於其複合材料型態學、機械性質、熱性質及電氣性質進行探討。 由掃描式電子顯微(SEM)觀察複合材料表面形態,經IPS改質之PI與無機填充料之間分散性、相容性良好。熱重分析(TGA)顯示,添加碳管與氮化硼後,高分子的熱穩定性提升。動態機械分析儀(DMA)顯示PII系列的儲存模數(E'')及損失模數(E")經由添加40wt%的碳管及氮化硼後,分別提升85.9%及144.20%。拉伸性質隨著剛硬性的無機材料含量增加,抗張強度、斷裂伸長率是降低的趨勢。電氣性質隨著氮化硼含量提升,其介電常數降低、表面阻抗提升。在熱傳導性測試中,聚醯亞胺在添加40wt%的碳管與氮化硼後,其導熱係數由0.3657 W/mK提升到0.8194 W/mK,顯示傳導的路徑及網絡形成,有助於複合材料的散熱行為。
In this study, polyamic acid prepolymer is prepared through three monomers: 4,4′-Oxydianiline (ODA), 3,3''-Dihydroxybenzidine (HAB) and Pyromellitic dianhydride (PMDA). Then the coupling agent (3-Isocyanatopropyl triethoxysilane IPS) was added and the hydroxy group on the HAB will further react with the IPS. Subsequently, the high thermal conductive inorganic matters: multi-walled carbon nanotube (CNTs) and boron Nitride (BN) were added into the polymer matrix, and the thermal imidization was then proceeded by dehydration via heating process. The morphology, mechanical, thermal and electrical properties of these composites were investigated. By the scanning electron microscopy (SEM), surface morphology of composite materials showed that good compatibility between PI and inorganic filler was found. Thermal gravimetric analysis (TGA) showed that thermal properties of polymer materials have been enhanced with the addition of CNTs and BN. Dynamic Mechanical Analyzer (DMA) showed that the increments of the storage modulus (E'') and loss modulus (E") for PII series loading with 40wt% of CNTs and BN, are 85.9% and 144.20%, respectively. Moreover, tensile strength and elongation at break are decreased with the increasing content of fillers. Further, the decreased dielectric constant and increased surface resistance were found with the increasing content of BN. The thermal conductivity of Polyimide was increased from 0.3657 W/mK to 0.8194 W/mK as adding of 40wt% of CNTs and BN. This indicates that the conductive paths and networks were formed, and can help the heat dissipation of composite materials.