- 學位論文
樹枝狀水性PU壓克力樹脂之合成、物性探討與光硬化動力學分析
Synthesis and Kinetics of UV-Curning of Waterborne Polyurethane Acrylate Dendrimer
摘要
本實驗主要以樹枝狀聚酯多元醇（Boltorn P500）為主體，其具有高度分枝 的球狀立體結構，丙烯酸羟乙酯（2-HEA）為原料分別與不同種類之二異氰酸酯 （IPDI、TDI、HMDI、HDI）反應，並利用末端基進行改質，合成出一系列樹枝 狀水性PU壓克力樹脂。在全程反應的過程中，分別藉由紅外線光譜儀(FT-IR)、 介質輔助雷射脫附游離/飛行時間質譜(MALDI-TOF-MS)和核磁共振光譜儀 (1H-NMR)來進行反應終點的判斷與樹脂結構的鑑定、分子量的測定。本實驗所合成出之一系列樹脂中，末端分別帶有5、9、13個PU丙烯酸官能基，探討各樹脂間物性的不同（黏度與溫度的關係、水中最大固含量、QUV耐黃變性測試、薄膜鉛筆硬度測試），並加入不同添加量的光起始劑（Photoinitiator）Doublecure-1173，在相同的環境溫度（40℃）之下，經UV光照射後，分析各樹脂在光硬化動力學(Kinetic)之反應速率和轉換率(Conversion)間的差異，主要測試儀器為DPA（Double Beam Photocalorimetric Accessory）。由實驗結果可發現，樹脂結構含剛性苯環結構，成膜後具有較高的硬度，且剛性結構造成立體障礙變大，相對提高樹脂黏度。而樹脂本身含親水基的多寡與結構剛性與否亦會影響樹脂在水中的最大固含量，結構中親水基多，含軟鏈，可提高固含量。若結構中不含共振芳香環，經QUV耐黃變測試，亦能減少經UV光照射而產生色變。在光硬化方面，增加光起始劑的濃度或提高接枝數，其轉換率（α）、反應速率（k）及反應級數（m）皆會變大，但光起始劑添加量有其極大值，過多，轉換率（α）、反應速率（k）、反應級數（m）皆會下降，因為大量的自由基快速的再結合所造成。綜括本實驗所合成之一系列水性樹支狀光固化樹脂與物性分析可知，PUA-IPDI-9，不僅在光固化動力學中有著優良的表現，且可溶解35％的水，固化成膜後具有B級的硬度，並在QUV耐黃變測試中有著優異的耐黃變特性。
並列摘要
In this study, a dendrimer with 19 sites was modified to form a waterborne oligomer with hydrophilic sites and polyurethane acrylate (PUA) sites. Four PU systems isophorone diisocyanate（IPDI）、toluene diisocyanate (TDI)、methylene-bis (4-cyclohexylisocyanate) (HMDI) and hexamethylene diisocyanate (HDI) were used; each of them had 5, 9, and 13 PUA sites, respectively. Experimental results revealed that the TDI system have a higher viscosity and lower solid content in water than the other systems,the HDI system was more stable than the other system in QUV test. The TDI system, however, exhibited better hardness than the other system, even though the final curing conversion of TDI was low. These results are owing to diisocynate’s structure,because TDI system have aromatic ring,so have a higher viscosity、greater hardness and lower solid content in water but easy lead to yellowing.Additionally, more PUA sites of a dendrimer were associated with greater hardness of the cured resin. In a UV-curing study, simulations revealed that the autocatalysis model could describe the UV-curing mechanism of the PUA-dendrimer system. Most of the reaction rate constant k and the final conversion α were highest at a concentration of the photoinitiator of approximately 5wt% for IPDI、TDI and HMDI systems,but in HDI system is approximately 3wt%,because HDI system have a lower viscosity. The reaction rates of all systems were highest when the number of PUA sites was nine. The final conversion of all the systems, however, was optimal when the number of PUA sites was 13.Finally and most importantly, TDI always had a lower rate constant k and final conversion α in all systems under similar conditions in studies that were conducted to examine the effects of photoinitiator concentration, number of PUA sites, and reaction temperature, revealing that the steric hindrance by the aromatic ring in TDI negatively influenced its curing kinetics. Summarize the results of all the experiments,PUA-IPDI-9 has the best performance in a series of tests.
參考文獻
延伸閱讀
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- 王博正（2010）。樹枝狀含硫高折射率光硬化樹脂之合成與物性探討〔碩士論文，國立臺北科技大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0006-1607201014484800
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- 邱怡瑛（2010）。樹枝狀水性光固化樹脂之合成與物性探討〔碩士論文，國立臺北科技大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0006-3001201010184800
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