以亞磷酸二乙酯作為熱延遲性的環氧樹脂 硬化劑及其硬化樹脂性質研究

Using diethylphosphite as a thermally latent curing agent for epoxy resins and the properties of the cured epoxy resins

魏文龍(Wen-Lung Wei)

指導教授 ： 劉英麟

中原大學/工學院/化學工程研究所/碩士(2003年)

https://doi.org/10.6840/cycu200300090

摘要

摘要
本研究藉由1H NMR及Pyrolysis GC/MS證明市售之磷酸酯化物diethyl phosphite(DEP)加熱後可脫出乙醇而形成磷酸活物種，進而對環氧樹脂進行硬化反應，所以對環氧樹脂之硬化反應具有熱延遲(thermal latent)之性質。並利用微差掃描卡計儀(DSC)探討DEP及其衍生物對環氧樹脂(BE188)硬化反應之熱延遲性和硬化反應動力學。結果發現DEP及衍生物，可直接添加至環氧樹脂中作為硬化劑使用，且與環氧樹脂硬化後之產物具有磷元素而耐熱性可達300℃，故可改善樹脂難燃性。
另外本研究也利用DEP與含氮之環氧樹脂(4-maleimido phenylglycidyl ether, MIE)進行硬化，探討當環氧樹脂同時含有磷及氮元素之難燃效果。又因為MIE本體具有imide結構相當耐熱，所以磷元素混入結構中，耐熱性質並無影響，並由熱重損失分析儀(TGA)証實DEP/MIE樹脂之熱穩定性可達350℃且難燃性佳。且DEP當作環氧樹脂(MIE)之硬化劑時，熱性質及極限氧指數值(LOI)比不含氮樹脂(DEP/BE188)大幅提升，證實磷/氮協成效應(synergistic effect )。
磷元素作為難燃劑時，會降低環氧樹脂之熱裂解溫度(Td)，但其具有較高的焦炭(char)含量，所以含磷環氧樹脂具有難燃效果。而樹脂燃燒後生成的焦炭保護層，在700℃以上高溫還是會繼續裂解。為了提高Char耐燃程度，我們將直徑10~20 nm colloidal silica(CS)奈米顆粒直接摻混到環氧樹脂中，製成奈米複合材料(nanocomposite)，並與常見雙胺型硬化劑(DDM)比較其熱性質。利用二種不同之熱裂解模式(Kissinger, Ozawa)，求得複合材料之熱裂解活化能。含無機奈米顆粒之樹脂可提升其熱性質且可以保護焦炭層在高溫區的裂解。

關鍵字

環氧樹脂 ； 協成效應 ； 難燃劑 ； 反應動力學

並列摘要

Abstract

Diethylphosphite (DEP) can be used as a thermally latent curing agent for epoxy resins by means of the formation of phosphonic acid active groups through the de-ethanol reaction of DEP. The mechanism and activation energy of the curing reaction and the thermally latent characteristics of DEP on curing epoxy resins were demonstrated with 1H NMR, pyrolysis-GC/MS, and DSC measurements. The cured epoxy resins exhibited good thermal stability over 300 ℃ and improved flame retardance alone with the introduction of phosphorus element from DEP curing agent. Therefore, this commercial available DEP compound was potentially used as thermally latent curing agent and flame retardant for epoxy resins.
While a maleimide-epoxy compound (4-maleimido phenylglycidyl ether, MIE) was cured with DEP, the resulting resins showed thermal stability over 350 ℃. Extremely high flame retardance was also observed with the DEP-MIE cured resins owing to the P-N synergistic effect on flame retardance. The properties of the DEP cured epoxy resins could be further leveled up with incorporating nanoscale colloidal silica to form epoxy-silica nanocomposites. Nanoscale silica also showed synergistic effect with phosphorus on improving the flame retardance of the cured epoxy resins. Moreover, the kinetics of the thermal degradation of the DEP cured epoxy resins were also investigated with thermogravimetric analysis.

並列關鍵字

flame retardant ； reaction kinetic ； synergistic effect ； epoxy resins

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