低介電多面體倍半矽氧烷寡聚物/環氧樹脂奈米複合材料之研究

Abstract

本文研究主要目的為改善環氧樹脂的介電性質並提升環氧樹脂的熱性質。在製備低介電環氧樹脂奈米複合材料方面，首先合成具有8個環氧基之多面體倍半矽氧烷寡聚物(OG)，及另一具有含氟原子與環氧基之多面體倍半矽氧烷寡聚物(OFG)，將此兩個化合物分別加入環氧樹脂中，再經光交聯與熱交聯。將多面體倍半矽氧烷寡聚物/環氧樹脂奈米複合材料塊狀薄膜以微差掃描熱卡計(DSC)，熱重分析儀 (TGA)，動態機械分析儀(DMA)等儀器來評估其熱性質並以電子顯微鏡來進行相形態之分析，另一方面則利用介電常數測試儀(DEA)來測定其介電值。 所合成之OG與OFG奈米化合物，因其具有環氧基可與光起始劑在紫外線下與環氧樹脂進行光交聯反應。所製備之多面體倍半矽氧烷寡聚物/環氧樹脂奈米複合材料其玻璃轉移溫度(Tg)變化會呈現出先升後降的情形；其主要原因為添加適量之矽氧烷寡聚物可促進環氧樹脂之交聯密度增加，但奈米化合物亦會造成環氧樹脂的自由體積增加並使熱性質在上述因素相互影響下會因添加的矽氧烷寡聚物數量不同而有不同的變化。 在介電性質方面，環氧樹脂本身其介電值為3.71；其加入10 phr的OG所形成的多面體倍半矽氧烷寡聚物/環氧樹脂奈米複合材料其介電值降為2.83；而加入10 phr的OFG所形成的多面體倍半矽氧烷寡聚物/環氧樹脂奈米複合材料其介電值更下降為2.76。環氧樹脂奈米複合材料的介電常數會隨著多面體倍半矽氧烷寡聚物含量增加而下降，其主要原因為多面體倍半矽氧烷寡聚物結構中所含的微細孔洞和環氧樹脂的自由體積增加與多面體倍半矽氧烷寡聚物具有含氟官能基的影響所至。 另一方面，在導入等量多面體倍半矽氧烷寡聚物的情形下，OFG化合物相較於OG化合物更能有效的降低複合材料之介電值，但亦能保有相同熱性質。在相形態分析上，經由電子顯微鏡分析，此二種多面體倍半矽氧烷寡聚物/環氧樹脂奈米複合材料為一微相分離系統(micro-phase separated system)；但掺有OG化合物之環氧樹脂具有較佳的分散形態，而含有OFG化合物之環氧樹脂具有較大的聚集區塊。

In this investigation, a polyhedral oligomeric silsesquioxane (POSS) with various functional groups was incorporated into the epoxy network that possessed low dielectric constant and higher thermal properties. In this thesis, we synthesized two nano-structure compounds. One is containing octa-epoxy group POSS derivative(OG) and the other is a containing with epoxy and fluoride group POSS derivative (OFG). These compounds(OG, OFG) were incorporated into the backbone of epoxy through UV curing. The thermal properties were characterized using DSC, TGA, and DMA. The dielectric constant was characterized using DEA. In dielectric property, the dielectric constant of plain resin is 3.71. For the POSS/Epoxy nanocomposites, the dielectric constant of the nanocomposite films are lower than that of plain resin and can be tuned by the amount of POSS molecules introduced in the nanocomposite film. The dielectric constant of the resultant nanocomposities are lower due to the increased free volume and less polar POSS molecules, and the micropore in the POSS molecules and the dielectric constant of OG containing epoxy resin is 2.83 and the dielectric constant of OFG containing epoxy resin is 2.76 under the same POSS particles. Due to OFG that possessed nanoporous and fluorine, it has a high efficiency to decrease the the dielectric constant of epoxy resin compared to OG. In morphology, the electron micrograps also provide POSS/Epoxy nanocomposites are microphase separation.