含苯基矽氧烷環氧樹脂/雙酚A環氧樹脂混成材料製備、特性與老化行為研究及新型液態奈米氧化鋯-矽氧烷混成樹脂合成與特性研究

Preparation, characterization and thermal aging behaviors of phenylmethylsiloxane-modified epoxy/ DGBEA hybrids, and Synthesis and characterization of novel liquid zirconium-siloxane hybrid resin

許嘉紋(Hsu, Chia Wen)

指導教授 ： 談駿嵩 ； 馬振基

國立清華大學/工學院/化學工程學系/博士(2015年)

摘要

本論文研究旨在以苯基甲基矽氧烷 (Phenylmethylsiloxane- modified epoxy, PMSE)改質環氧樹脂製備有機無機混成透明材料應用在LED封裝材料特性，以及深入探討混成透明材料硬化交聯網構型與在熱老化過程中產生的性質變化。針對改善矽氧烷改質脂環族環氧樹脂 (silicone-modified cycloaliphatic epoxy, SEP)硬化反應性較低問題，嘗試以溶膠-凝膠 (Sol-gel)製程合成新型無溶劑液態氧化鋯混成樹脂 (Zr–QR)，探討此Zr–QR對硬化反應加速作用並製備具高透明性矽氧烷改質脂環族環氧樹脂-氧化鋯混成奈米複合材料。
本論文第一部份研究旨在以苯基甲基矽氧烷改質環氧樹脂 (Phenylmethylsiloxane-modified epoxy, PMSE)與傳統雙酚A環氧樹脂 (DGEBA)用甲基六氫苯酐 (MHHPA)硬化交聯製備形成有機/無機混成透明材料，藉以改善傳統透明環氧樹脂耐熱老化特性應用在LED封裝材料；研究高溫熱老化對此混成材料特性的影響以及對應到LED出光效能穩定性。利用DSC和FTIR研究混成材料之硬化行為，以反應動力學分析混成材料硬化活化能，混成材料在150℃長時間老化的光學特性，機械性質以及封裝之LED出光效能分別由分光色度計、DMA和積分球分析。
研究結果顯示，DGEBA–PMSE混成材料之光穿透度大於88%，並且在150℃ 30天熱老化實驗後之光穿透度下降10%，此光學穩定性同時也對應到封裝LED出光效能 (Light output)特性提昇上，30天熱老化實驗後，DGEBA–PMSE混成材料其LED出光效能較DGEBA–MHHPA提升19%。除了光學特性影響LED出光效能穩定性之外，從DMA機械分析上也發現，DGEBA–PMSE混成材料在熱老化過程中alpha 轉變溫度 (Alpha relaxation temperature, Tα)和鬆弛強度 (Relaxation strength)有增加的現象，對於LED出光效能產生其他影響。機械性質的變化原因來自於分子重新排列，利用TEM觀察結果顯示，這個現象發生在混成材料奈米尺度的範圍內，重新排列造成材料變硬而應力累積導致LED出光效能下降。因此，在高溫長時間老化實驗中，LED出光效能穩定性同時受到材料光學特性和機械特性影響，在0.2當量PMSE改質混成材料配方中，兼具光學與機械特性穩定使得封裝LED有最穩定之出光效能，其出光效能分別較DGEBA–MHHPA和DGEBA–PMSE-0.4提升19%和22%。
本論文之第二部分延續第一部份研究，對於混成材料於熱老化過程於奈米尺度範圍內的分子重排現象，進一步研究DGEBA–PMSE混成材料硬化交聯網構型與不同老化溫度下結構鬆弛特性，利用動態機械分析儀 (Dynamic mechanical analyzer, DMA)分析混成材料動態機械性質進而分析其硬化交聯網構型，再利用正電子湮滅壽命光譜儀 (Positron annihilation lifetime spectroscopy, PALS)深入研究DGEBA–PMSE熱老化過程中自由體積和自由體積分率變化；除了研究混成材料硬化交聯網構型之外，也將混成材料於熱老化過程中鬆弛行為進行量化分析。
從DMA結果分析得知，以0.2當量PMSE改質混成材料配方(DGEBA–PMSE-0.2)和0.4當量PMSE改質混成材料配方(DGEBA–PMSE-0.4)硬化交聯後材料之玻璃轉移溫度隨著PMSE的含量提高而下降，但α轉變峰半高寬、交聯密度卻未隨之下降，反而高於PMSE–MHHPA與DGEBA–MHHPA，說明具有甲基苯基取代基的矽氧烷鏈硬化的PMSE交聯網與DGEBA交聯網形成互穿現象，形成互穿高分子交聯網 (Interpenetrating polymer networks, IPNs)，進而增加高度發散的物理交聯點。在PALS的o–Ps intensity研究中，利用雙疊加式指數函數迴歸模型 (Double additive exponential model)和KWW迴歸模型 (Kohlrausch–Williams–Watts exponential model)深入研究DGEBA–PMSE-0.4在150℃和55℃熱老化過程的結構鬆弛現象，其中雙疊加式指數函數迴歸模型對DGEBA–PMSE-0.4在熱老化過程中的結構鬆弛行為有較佳的描述，從150℃時得到單一鬆弛時間表示整個IPN結構都在進行鬆弛過程，而在55℃熱老化實驗中，雙疊加式指數函數迴歸模型公式提供了IPN結構鬆弛行為更深入的訊息，表示了兩個個別鬆弛時間，37.4小時 (ζ1)和753.6小時 (ζ2)，其中較短鬆弛時間ζ1屬於處於橡膠態的PMSE硬化交聯網結構鬆弛，較長鬆弛時間ζ2屬於處於玻璃態的DGEBA硬化交聯網結構鬆弛，因此可以說，雙疊加式指數函數迴歸模型對於此DGEBA–PMSE混成材料可以有效預測其鬆弛行為。
本論文之第三部分研究溶膠-凝膠 (Sol-gel)合成新型無溶劑液態氧化鋯混成樹脂 (Zr–QR)，先利用長鏈矽氧烷醇(Silanol-terminated polydimethylsiloxane, DMS-S12)與Zirconium butoxide形成反應鍵結並由Zirconium butoxide形成之氧化鋯團簇物(Zirconium butoxide)隔開，再利用反應性矽烷 (γ-glycidoxypropyltrimethoxysilane, Z-6040)將氧化鋯混成樹脂粒徑穩定控制在奈米等級。利用FTIR和1H-NMR監控合成步驟，TEM觀察氧化鋯混成樹脂有序型態；再將氧化鋯混成樹脂與熱穩定型矽氧烷改質脂環族環氧樹脂 (Silicone-modified cycloaliphatic epoxy, SEP)製備成高透明熱穩定之奈米複合材料，利用FTIR、DSC研究其硬化行為，並以分光色差計分析光學特性以及以TEM進行微/奈型態觀察。
研究結果顯示，合成的Zr–QR為液態並具有有序型態，FT-IR觀察到特徵吸收968 cm−1證實–Si–O–Zr– hetero-linkages的形成，可有效降低了zirconium butoxide水解縮合速率。 1H-NMR觀察到化學位移2.5- 3.8 ppm證實Z-6040的存在， Z-6040可將有序相尺寸穩定控制在小於5 nm。Zr–QR與矽氧烷改質脂環族環氧樹脂有相容性，搭配液態酸酐硬化劑 (methylhexahydrophthalic anhydride, MHHPA)製備奈米複合材料，從FT-IR結果顯示，Zr–QR和MHHPA先反應形成有1464 cm−1 and 1564 cm−1特徵吸收的螯合配位體和有1704 cm−1特徵吸收的carboxylic acid，其中carboxylic acid可以促進SEP和MHHPA之間的反應。在DSC中反應放熱溫度在166℃，而螯合配位體可以抑制Zr–QR自身縮合反應速度，所製備的SEP–Zr–QR奈米複合材料具有高光學穿透度，在可見光範圍為88%。

關鍵字

矽氧烷環氧樹脂 ； 發光二極體封裝材料 ； 奈米氧化鋯-矽氧烷混成樹脂 ； 有機-無機混成材料

並列摘要

The aims of this research are development the silicone-modified epoxy based organic-inorganic transparent hybrids for high performance LED encapsulant applications. The thermal stability and cured network relaxation behaviors of transparent hybrids during thermal aging were investigated. Moreover, a liquid zirconium hybrid resin (Zr–QR) was synthesized through sol-gel reactions in order to increase the reactivity of silicone-modified cycloaliphatic epoxy. The acceleration ability of the Zr–QR and the fabrication of a transparent silicone-modified cycloaliphatic epoxy– zirconium nanocomposite were studied in this research.
The first part of this study is to investigate the thermal stability of the diglycidyl ether of bisphenol A (DGEBA)–methylhexahydrophtalic anhydride (MHHPA) modified with phenylmethylsiloxane-modified epoxy (PMSE) and the effects of this hybrid on the performance of light emitting diodes (LEDs). The optical and dynamic mechanical properties of the materials, and the effects of these properties on the light output from the encapsulated LEDs, were studied following long-term thermal ageing at 150℃. The DGEBA–PMSE hybrids were highly transparent and its optical stability was shown in the stable light output of the LED, which was 19% higher than that of LEDs encapsulated by DGEBA–MHHPA after 30 days. The conformation rearrangement occurred in the nanoscale domain of the hybrids after thermal ageing, which caused the dynamic mechanical effect on the LED performance, as demonstrated by TEM. The hybrid modified using 0.2 equivalents of PMSE possessed both optical and dynamic mechanical stability were investigated, and resulted in the most stable LED performance.
In the second part of this study, the cured network conformations and structural relaxation behaviours of the diglycidyl ether of bisphenol A (DGEBA)-methylhexahydrophthalic anhydride (MHHPA) modified with phenylmethylsiloxane-modified epoxy (PMSE) at different aging temperatures were studied using dynamic mechanical analysis (DMA) and positron annihilation lifetime spectroscopy (PALS). The DMA results revealed that the cured PMSE network can insert into the cured DGEBA network to form interpenetrating polymer networks (IPNs). The structural relaxation behaviours of DGEBA–PMSE-0.4 prepared using DGEBA, PMSE, and MHHPA at a ratio of 0.6:0.4:1 by equivalent weight were studied using PALS at 150°C and 55°C. The aging-induced free volume relaxation parameters of DGEBA–PMSE-0.4 at 150°C and 55°C were investigated using the double additive exponential model and the Kohlrausch–Williams–Watts exponential model. For double additive exponential model, only one relaxation time (ζ) of 584.5 h was found at 150°C; By contrast, there were two separate relaxation times of 37.4 h (ζ1) and 753.6 h (ζ2) at 55°C. The ζ1 of the IPNs hybrid can be attributed to the network relaxation of PMSE, and the ζ2 can be attributed to the network relaxation of DGEBA at 55°C. The results suggested the double additive exponential model can effectively predict DGEBA–PMSE hybrid relaxation behaviours.
In the third part of this study, a liquid zirconium hybrid resin (Zr–QR) was synthesized through sol-gel reactions of zirconium butoxide with silanol-terminated polydimethylsiloxane (DMS-S12) and γ- glycidoxypropyltrimethoxysilane (Z-6040). The sol-gel reactions were monitored using Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance spectroscopy. The Zr–QR morphology was investigated using field emission transmission electron microscopy. The Zr–QR had a well-ordered morphology and the dimension was less than 5nm. These properties were achieved because DMS-S12 was used to separate the zirconium clusters and Z-6040 was used to stabilize the Zr–QR. The acceleration of the curing reaction between silicone-modified cycloaliphatic epoxy (SEP) and methylhexahydrophthalic anhydride (MHHPA) caused by the Zr–QR was investigated. Differential scanning calorimetry and FT-IR spectroscopy investigations showed that the Zr–QR first reacted with MHHPA, producing chelating ligands and carboxylic acid. Unlike in the conventional method (adding acetic acid to cause non-reactive chelating ligands to form the carboxylic acid), the carboxylic acid can accelerate the curing reaction between the SEP and MHHPA effectively. The chelating ligand generated from the Zr–QR and MHHPA suppressed the gelation of the Zr–QR itself during the nanocomposite (SEP–Zr–QR) curing process. The cured SEP–Zr–QR nanocomposite exhibited excellent optical transmittance which was above 88% at visible wavelengths.

並列關鍵字

phenylmethylsiloxane-modified epoxy ； LED encapsulant ； zirconium-siloxane hybrid resin ； organic-inorganic hybrid materials

參考文獻

26. Mohammad Bashar, Pierre Mertiny, Uttandaraman Sundararaj, “Effect of Nanocomposite Structures on Fracture Behavior of Epoxy-Clay Nanocomposites Prepared by Different Dispersion Methods”, Journal of Nanomaterials, Vol. 2014(1): 1-12, 2014.

57. Ismail Ab Rahman, Vejayakumaran Padavettan, “Synthesis of Silica Nanoparticles by Sol-Gel: Size-Dependent Properties, SurfaceModification, and Applications in Silica-Polymer Nanocomposites—A Review”, Journal of Nanomaterials, Vol. 2012, Article ID 132424, 15 pages, 2012.

3. Shu-Hang Liao, Chih-Hung Hung, Chen-Chi M. Ma, Chuan-Yu Yen,Yu-Feng Lin, Cheng-Chih Weng, “Preparation and properties of carbon nanotube-reinforced vinyl ester/nanocomposite bipolar plates for polymer electrolyte membrane fuel cells”, Journal of Power Sources, Vol.176(1): 175-182, 2008.

4. Qiang Yin, Kang-ning Sun, Ai-ju Li, Lei Shao, Song-ming Liu, Chang Sun, “Study on carbon nanotube reinforced phenol formaldehyde resin/graphite composite for bipolar plate”, Journal of Power Sources, Vol.175(2): 861-865, 2008.

5. Yu-Sheng Wang, Shin-Yi Yang, Shin-Ming Li, Hsi-Wen Tien, Sheng-Tsung Hsiao, Wei-Hao Liao, Chia-Hong Liu, Kuo-Hsin Chang, Chen-Chi M. Ma, Chi-Chang Hu, “Three-dimensionally porous graphene–carbon nanotube composite-supported PtRu catalysts with an ultrahigh electrocatalytic activity for methanol oxidation”, Electrochimica Acta, Vol.87: 261-269, 2013.