低介電Benzoxazine共聚物及聚酯之關係

本論文是利用芳香族二胺DDM、ODA分別以三步法合成單體(1-2)，及傳統法合成單體(3-6)為雙胺基質的Benzoxazines，並藉由NMR來鑑定其結構的正確。這一系列的Benzoxazines經過高溫硬化後，具有高玻璃轉移溫度（Tg）、高熱裂解溫度（Td）和高燃燒後的殘餘量（Char yield），有著較好的熱穩定性。 由於BADCY在硬化過程中因分子量上升，使得黏度升高系統流動性差，此結果容易導致末端OCN殘留未反應。殘留下來的OCN極性高，使得介電常數不易降低。因此我們將Benzoxazine單體與BADCY一同共聚，利用Benzoxazine高溫時開環所產生的酚基與OCN先形成Imidocarbonate，藉由降低交聯密度達到增加硬化過程流動性的效果，使得殘存的OCN減少以降低極性，而達到降低介電常數的結果，並對其熱性質做探討。再來針對共聚物的吸水性做改善，利用一步法的方式合成出帶有萘環和甲基兩種取代基的Benzoxazine單體(3~6)，由於萘環和甲基皆為疏水性的取代基，因此將合成出的單體與BADCY一同共聚，期望能降低其吸濕性及介電係數並藉由Benzoxazine良好的尺寸安定性使得共聚物的熱膨脹係數降低。 第二部分則是利用芳香族親核性取代反應，合成出帶有CF3基團的高分子PPO。首先將2-Chloro-5-nitrobenzotrifluoride和4-Methoxyphenol在鹼觸媒下合成出單體(1)，再藉由Boron Tribromide進行去甲基化得到一邊OH、一邊Nitro而鄰位為CF3的單體(2)，利用CF3活化leaving group nitro基進行nitro displacement反應合成出帶有CF3的聚氧苯高分子(3)。此高分子在許多有機溶劑下，如NMP、 DMAc、DMSO、DMF、m-cresol等皆有相當好的溶解性。而導入含氟基團也能增加其自由體積，降低介電常數。We synthesize compound(1~2) via three-step synthetic method using typical aromatic diamines – DDM,ODA and via traditional method synthesize compound(3-6). The structures of the monomers were confirmed by 1H-NMR, 13C-NMR, 1H-1H 2D NMR and 1H-13C 2D NMR spectra. The high crosslining polymer was prepared co-curing with compounds(1~6) and BADCY. The spectraland analytical data supported the possibilities of further polymerization through the insertion of the phenolic -OH of polybenzoxazine to cyanate group to form the intermediate iminocarbonate, which further induce curing of cyanate ester to form polycyanurate. For copolymers, the iminocarbonate linkages, resulting from the reaction of phenolic OH of polybenzoxazine and high polar Functional Group OCN group, were able to reduce dielectric constant. The thermal properties of (3-6) can be enhanced via the copolymerization, and the water absorption of BADCY was reduced via the copolymerization. Polyphenylene oxide(PPO) possesses excellent electrical properties (low-dielectric constant) and thermal resistant , however owing to high molecular weight, its reactivity and process ability are very low for electronic applications. The nucleophilic aromatic substitution reaction (SNAr) has been known as a very effective one for the formationof aromatic ether groups and utilized in the synthesis of many organic and polymeric compounds. A properly activated nitro group is also displaced readily, but it produces a reactive nitrite ion as a byproduct which causes side reactions at elevated temperature. However,trifluoromethyl groups act as an effective activating group for the nucleophilic nitro displacement reaction at relatively high temperature due to the inertness of perfluoroalkyl groups to the nitrite ions. Another advantage of the CF3 activating group is that the incorporation of fluorines into the polymer chain provides some desirable properties such as low dielectric constant, low moisture absorption, and good solubility