DSC及流變儀對UV光固化樹脂動力學之研究與物性探討

The Study on Kinetics and Physical Properties of UV curable resins by DSC and Rheometer

宋文清(Wen-Ching Sung)

指導教授 ： 芮祥鵬

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2010年)

摘要

本研究為探討恆溫下雙官能基樹脂自由基及陽離子光固化系統於熱分析及流變動力學之差異。自由基光固化系統將具有壓克力基之1,6-Hexanediol dimethacrylate (HDDMA)加入裂解型光起始劑HMPP，陽離子光固化系統將俱有環氧基之3,4-Epoxycyclohexylmethyl-3,4-cyclohexanecarboxylate (CELLOXIDE 2021P)加入路易士酸光起始劑CHIVACURE 1176分別配置不同濃度再曝照紫外光形成網狀交聯結構。固化過程以Photo-DSC亦稱為DPA (Double Beam Photocalorimetric Accessory)靜置偵測反應吸、放熱，換算得熱能轉化率，代入Kamal方程式；另一方面藉由流變儀於固化過程中，樹脂在動態(dynamic)狀態產生黏彈性指標儲存模數(G’)之轉化率，代入Malkin and Kulichikhin方程式。雖然同為自催化反應，但兩種方式得到之動力學參數存在不同程度差異。自由基及陽離子光固化系統在DPA皆觀察到在恆溫環境添加光起始劑濃度存在一臨界值，超過此臨界值會依序降低轉化程度。由流變動力學發現自由基系統趨勢與熱分析動力學類似，存在Trommsdorff effect；陽離子系統G’ 轉化程度及轉化速率隨光起始劑含量增加相差將近八倍。動態流變測試中，自由基系統在不同振幅(shear strain)下因為其聚合過程瞬間即達成固化，幾乎不影響最終平衡模數(G’∞)，然而陽離子系統固化過程所受shear strain越大，G’∞會因鏈成長聚合過程中路易士酸光起始劑之中間產物受到干擾使G’增長受限。

關鍵字

紫外光固化 ； 流變動力學 ； 儲存模數 ； DSC ； 流變儀 ； Kamal ； Malkin

並列摘要

The differences of free radical type and cationic type UV curable resins with two functionalities individually between calorimetric and rheological kinetics were investin-
gated. The free radical photopolymerization mixture of 1,6-Hexanediol dimethacrylate (HDDMA) with acrylic groups that is added with cleavage photoinitiator HMPP ,and the cationic photopolymerization mixtures of 3,4-Epoxycyclohexylmethyl-3,4-cyclohexanecarboxylate (CELLOXIDE 2021P) that is added with Lewis acid photoinitiator CHIVACURE 1176 were prepared in different contents respectively then formed cross-linking networks by being irradiated ultraviolet beam. During the curing process, Photo-DSC which is also called DPA (Double Beam Photocalorimetric Accessory) was used to detect endothermic or exothermic reactions without mobilizing, then the calorimetric conversions were obtained and were used as Kamal’s model. On the other hand, rheometer is used to generate rheological conversions that were calculated by storage modulus (G’) during curing processes. Thus the values are used for Malkin and Kulichikhin’s model. Although both methods are autocatalystic processes, there are distinct differences in acquired kinetic parameters. On DPA data, free radical and cationic UV curable systems were both observed to have critical values for the amounts of photoinitiator in isothermal environment. Conversion would be reduced if the critical value is exceeded. We found that the trends on rheological kinetics were similar to calorimetric kinetics, which existed ”Trommsdorff effect”. As the photoinitiator contents increase from 0.5 wt% to 7 wt%, the rheological conversion degree and conversion rate increase nearly eight times. Curing process could not affect the ultimate storage modulus (G’∞) of free radical photopolymerization under different strain amplitudes in dynamic rheological tests because it solidifies almost immediately. However, the G’ of cationic photopolymerization was affected due to chain growth mechanism interfered with dynamic shear strain on intermediate of decomposed photoinitiator.

並列關鍵字

UV curable ； rheological kinetic ； storage modulus ； DSC ； rheometer ； Kamal ； Malkin

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