溶劑效應對聚亞醯胺/氮化硼複合材料之導熱特性影響

Abstract

本論文主要研究分成兩部分：(1) 利用 pyromellitic dianhydride (PMDA) 雙酸酐單體與4,4'-diaminodiphenyl ether (ODA) 雙胺單體合成聚醯胺酸，並使用高導熱材料氮化硼混成聚醯胺酸，經過熱亞醯胺化和成聚亞醯胺，比較使用不同溶劑 : 二甲基乙醯胺、砒碇以及添加重量百分比5% 二乙二醇二甲醚 + 95%砒碇對合成混成聚亞醯胺薄膜過程的影響，進行一系列熱性質分析、導熱性質的研究，來評估材料的基本特性分析；(2) 探討相同添加量的氮化硼的聚亞醯胺混成薄膜之導熱性質與溶劑之間關係的研究。 本研究選擇三個系列的純聚亞醯胺與以及聚亞醯胺與氮化硼的混成薄膜作比較，第一系列為使用砒碇當溶劑的(P系列)，第二系列是使用二甲基乙醯胺當溶劑的(D系列)，作為對照組，以及以P系列為基礎、使用二乙二醇二甲醚與砒碇之共溶劑系統的(C系列)，以此這三個系統去探討溶劑對合成的效應；從本研究可以發現因溶劑不同D系列的純聚亞醯胺導熱係數值0.11W/(m•K)比另外兩系統P及C系列約0.15 W/(m•K)低，在D系列氮化硼的加入並沒有對導熱性質有很明顯的改善現象。整體量測實驗結果證實使用砒碇取代二甲基乙醯胺做為合成過程中溶劑有助於提升兩者間的反應性，尤其是P系列僅需添加重量百分比13%的氮化硼其導熱數值就可以達到0.51 W/(m•K)，與D系列中相同添加量相較該數值僅為0.17 W/(m•K)以及共溶劑系統C系列的0.22 W/(m•K)數值，這代表溶劑效應確實存在。

This study was divided into two parts. In the first part of the experiment, polyamic acid (PAA) precursor was synthesized by using 4, 4’-diaminodiphenyl ether (4, 4'-ODA) and pyromellitic dianhydride (PMDA) monomers. In oreder to produce PI/BN composites, boron nitride (BN) which was regarded as the high thermal conductivity material was prepared by physical mixing and thermal imidization process. Furthermore, the solvent effect by using different solvent such as dimethyacetamide (DMAc), pyridine and 5 wt% diethylene glycol dimethyl ether + 95 wt% pyridine in this process were carefully observed. To estimate the basic material characteristics of PI/BN composites, thethermal stability and thermal conductivityof PI/BN composites were analyzed. In the second part of experiment, the studying was focus on the relationship between the thermal conductivity and the solvent effect of PI/BN composites which were in the same BN content. In this study, the three series of pure PI and PI/BN composites were chosen to compare. The first series was using pyridine as the solvent (P series), the second series was using DMAc as the solvent (D series) as a comparison with P series. The co-solvent C series were synthesized by using pyridine which was the foundation in the P series and diethylene glycol dimethyl ether . As the result, these three series were studied on solvent effect in producing process. In this study, different solvents in D series showed pure PI was 0.11W /(m-K) of the thermal conductivity and was lower than the P and C series which were around 0.15W /(m-K) of the thermal conductivity. Also, adding BN just had a little improvement in the thermal conductivity. At the last, the experimental result proved that substituting pyridine for DMAc as the solvent in the process made a advantageous reaction with PI and BN. Above all,only adding 13 wt% BN content in the P series had 0.51W /(m-K) of the thermal conductivity; in the D series was 0.17W /(m-K) and in the C series was 0.22W /(m-K). These results show that the solvent effects exactly exist.