新穎含矽氧烷、醯亞胺聚氧代氮代苯并環己烷材料製備及其特性之研究

Abstract

在高分子研究領域中，化學性質與物理性質皆具有相當的重要性，且兩者是相輔相成的，我們可藉由材料分子結構設計、化學改質/ 合成的方法來滿足某些物理性質的需求、或以物理性質研究來延續合成產物的應用性與實用性。本論文以含矽氧烷、醯亞胺聚氧代氮代苯并環己烷(siloxane-imide-containing polybenzoxazine)為研究主體，內容分列為三大主題：

1. 新穎Siloxane-imide-containing benzoxazine (BZ-A1與BZ-A6)單體合成 在以往的文獻中，polybenzoxaizne聚合物有許多優點：優異的熱性質(高Tg、高裂解溫度)、無須催化劑即可進行聚合反應，在我們實驗室的先前研究中也發現此聚合物具有較鐵氟龍更低的表面能，是一個新穎的疏水低表面能材料。此外，polybenzoxazine 較一般常見的含氟低表面能材料具有價格便宜與易於製程的優點。此研究中，我們於benzoxazine 主體上導入siloxane-imide 結構，選擇不同矽氧烷鏈長的起始物合成出不同矽氧烷鏈長(分子量)的氧代氮代苯并環己烷單體 (BZ-A1, BZ-A6)。藉由siloxane-containing 增加材料的柔軟特性(flexibility)與耐候特性、藉由imide-containing維持材料的熱性質、使Tg不因siloxane導入而下降。

2. Siloxane-imide-containing benzoxazine硬化行為與聚合物特性探討 此部分針對siloxane-imide-containing benzoxazine硬化行為進行探討，BZ-A1與BZ-A6不但具有一般benzoxazine自開環反應的優點，形成polybenzoxazines (PBZ-A1與PBZ-A6)後聚合物的彈性模數(storage modulus)在MPa 範圍間，較bisphenol A 型態的polybenzoxazine的GPa範圍降低了許多，而且當siloxane含量較多時(PBZ-A6)可以得到一單獨的薄膜(a free-standing film)，足見解決了現有polybenzoxazine過脆的缺點。而在此benzoxaizne 主鏈上亦導入imide 基團，因此聚合物的Tg可以大於180℃，不因siloxane 軟鏈段的添加而降低Tg。Siloxane-imide-containing polybenzoxazines也是一疏水材料，PBZ-A6具有極低的表面能(~12.4 mJ/m2)，PBZ-A1與PBZ-A6同時也展現了極佳的耐熱與耐紫外光特性，有機會應用於自清潔與耐候材料上。

3. Siloxane-imide-containing polybenzoxazine/ epoxy 共聚合物(copolymer) 系統探討 除了Siloxane-imide-containing benzoxazines本身聚合反應與特性探討外，此部分我們選擇siloxane-containing epoxy與之進行共聚物反應(copolymerization)，除了發現共聚物中三級胺鹽含量可催化反應、降低反應溫度外，此共聚物仍具有良好熱性質、耐熱與耐紫外等優異特性，本研究我們利用Kissinger mthod針對siloxane-containing共聚合物進行反應動力學探討。

The physical and chemical properties are both important in the polymer researches. We can enhance many properties of polymers by chemical methods (i.e. variation of the functional groups, structure design and synthesis of polymers). By doing detailed studies of physical properties of polymers, we can discover numerous applications of them. In this study, we focus on three major subjects which based on the siloxane-imide-containing polybenzoxazines:

1. Synthesis of novel siloxane-imide-containing benzoxazines (BZ-A1andBZ-A6) Polybenzoxazines are reported to possessed many advantages, good thermal properties (high Tg, high decomposed temperature), cured without catalyst, etc. In our previous study, surface free energies of polybenzoxazines are even lower than that of pure poly(tetrafluoroethylene) (Teflon). In this study, siloxane-imide containing structure was introduced into the main chain of benzoxazine. Novel siloxane-imide-containing benzoxazines, BZ-A1 and BZ-A6 were synthesized from various siloxane-conatining starting material, siloxane-imide-containing di-anhydride. The novel polybenzoxazines have flexibility properties and good weather resistance due to siloxane-containing in the structure. The siloxane-imide-containing polybenzoxazines remain its high Tg since the imide-containing group. These polybenzoxazines comprise a new class of low-surface-free-energy and weather resistant materials, they are cheaper to prepare and easier to process than are conventional fluoropolymers and silicones.

2. Curing behavior of siloxane-imide-containing benzoxazines and properties of polybenzoxazines Curing behavior of siloxane-imide-containing benzoxazines and properties of polybenzoxazines were discussed in this study. BZ-A1 and BZ-A6 were crosslinked without any catalyst. Polybenzoxazines from BZ-A6 has lower storage modulus in mega-pascal scale, much lower than the typical bisphenol A type polybenzoxazine which storage modulus is in giga-pascal scale. A flexible, free-standing film could be obtained of PBZ-A6 which has more siloxane-containing segment in benzoxazine. Tg of novel polybenzoxazine is higher than 180℃ since imide group was introduced into the main chain of benzoxazine. Siloxane-imide-containing polybenzoxazines also have hydrophobic properties. PBZ-A6 has extremely low surface free energy as 12.4 mJ/m2. PBZ-A1 and PBZ-A6 have opportunity to be weather resistant or self-cleaning materials because of their good thermal and UV resistant properties.

3. Copolymerization of siloxane-imide-containing polybenzoxazine and epoxy resin Siloxane-imide–containing benzoxazine, BZ-A6, was copolymerized with siloxane-epoxy, GT-1000. The curing behavior of the copolymers was studied using DSC and FT-IR, which indicated a lower curing temperature of 150 ℃. The activation energy (Ea) of BZ-A6/ GT-1000 copolymer is 59.4 KJ/mol. from Kissinger method. The siloxane benzoxazine-epoxy mixture exhibited higher thermal stability, exhibited higher char yield as 44.6% and higher decomposed temperature at 364.9 ℃. Moreover, the water contact angle of the BZ-A6/ GT-1000 copolymer is more stable than the conventional bisphenol A type benzoxazine-epoxy, Ba/ DGEBA, during the UV exposure process, indicating that the benzoxazine-epoxy mixture is more suitable to apply as a hydrophobic material with UV resistant requirement. There are wide applications of siloxane benzoxazine-epoxy mixture since its lower curing temperature and good temperature- and UV- resistant properties.