本研究合成由含對稱第三丁基之二胺單體1,4-Bis(4-aminophenoxy)2,5-di-tert-butylbenzene (DTB/O/NH2)與不對稱第三丁基之二胺單體1,4-Bis(4-aminophenoxy)2,6-di-tert-butylbenzene (P/DTP/NH2)與三種酸酐：1,4-Phenylene bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate)(TAHQ)、3,3',4,4'-Biphenyltetracarboxylic dianhydride(BPDA)、4,4'-Hexafluoroisopropylidene daphthalic dianhydride(6FDA)進行聚縮合反應合成聚醯亞胺(PI)，其固有黏度範圍在0.28~2.19 dL/g之間，均可塗佈成具有韌性之薄膜；這些聚合物有好的熱安定性，於氮氣下10%熱重損失溫度皆在451"℃" 以上，而氮氣下的開始裂解溫度也在426"℃" 以上；在機械性質方面PI聚合物薄膜的抗張強度介於82~111 MPa；PI聚合物之吸水率介於0.56~1.56%之間，而吸水率隨著交聯密度的上升而下降；這些PI聚合物也具有低的介電常數(Dk)與損耗因數(Df)，在10 GHz下Dk介於2.67~3.05之間而Df介於0.0049~0.013之間。而本研究也探討交聯形成網狀結構來限制分子運動與Df之關係，選用兩種末端基：Maleic anhydride(MA)與Nadic Anhydride (NA)形成交聯PI共聚物，交聯後PI共聚物，在目前交聯度設計下顯示無法有效降低Df，這可能是因為交聯度不夠高，因而無法有效抑制分子鏈運動。

In this study, the diamine monomer 1,4-Bis(4-aminophenoxy)2,5-di-tert-butylbenzene (DTB/O/NH2) containing symmetric tert-butyl groups and 1,4-Bis(4-aminophenoxy)2,6-di-tert-butylbenzene (P/DTP/NH2) containing asymmetrical tert-butyl groups were synthesized. The polyimides (PIs) were synthesized by condensation polymerization from these two monomer, with three of anhydrides, 1,4-Phenylene bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate)(TAHQ), 3,3',4,4'- Biphenyltetracarboxylic dianhydride(BPDA) and 4,4'-Hexafluoroisopropylidene-daphthalic dianhydride(6FDA).They had inherent viscosities of 0.28~2.19 dL/g, and they could form tough and flexible films. The PIs exhibited high thermal stability with 10% decomposition temperature more than 451"℃" in nitrogen, and their onset temperature was more than 426"℃" in nitrogen. These films exhibited good mechanical properties with tensile stress between 82~111 MPa. The water uptake of PIs were between 0.56~1.56% and decreased with the increase of crosslink density. These PIs also had low dielectric constant (Dk) and low dissipation factor (Df). The range of Dk at 10 GHz is between 2.67 and 3.05, while the range of Df is between 0.0049 and 0.013. We also investigated the relationship between cross-linking to form a network structure to limit molecular motion and decrease Df. We chose two end-capped Maleic anhydride (MA) and Nadic Anhydride (NA) to form cross-linking PI copolymers. After cross-linking, Df of those PIs did not obviously reduce under current cross-linkage design, which might be because the degree of cross-linking was not high enough to effectively inhibited the movement of molecular chains.

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