分枝狀聚酯之合成與流變性質

Rheological Properties and Synthesis Of Branched Polyesters

林士勛(Shih-Hsun Lin)

指導教授 ： 鄭國忠

國立臺北科技大學/工程學院/化學工程研究所/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00402

摘要

本研究使用環氧樹脂以及其他具反應性官能基單體經由開環聚合反應後產生分枝狀聚脂，合成後比較不同結構分枝狀聚酯的差異，並利用熱分析探討不同結構所造成的物性變化，以及使用流變儀探討不同結構分枝狀聚酯的流體性質。利用凝膠滲透色層分析儀(GPC)測量其分子量，微差掃描熱卡計(DSC)及熱重分析儀(TGA)分析其熱性質，傅立葉轉換紅外線光譜儀(FTIR)與核磁振共儀(NMR)鑑定其結構，並利用錐-平板式流變探討高分子流變性質之影響。結果發現四種分枝高分子之重量分子量分布於4200~9000g/mol，由滴定方法測其轉化率皆為90%以上，其玻璃轉移溫度(Tg)則都低於室溫，依結構的不同介於-42~-14oC之間。分子作用力越大，或含結晶鏈段，此現象導致高分子的流動性下降。所合成之分枝狀聚酯高分子，在頻率與剪切速率較高時將會呈現剪切稀釋(shear thinning)非牛頓流體現象，可利用Carreau-Yasuda方程式 描繪其剪切變稀的變化，並且計算其鬆弛時間，觀察出鬆弛時間會隨著溫度上升而降低，與利用Havriliak –Negami 方程式描述動態儲存模數與損失模數和頻率之關係。本研究合成之分枝狀聚酯預期可作為增韌劑或者牙醫材料之可塑劑。

關鍵字

增韌劑 ； 分枝狀聚酯 ； 增韌 ； 流變性質 ； 熱性質

並列摘要

Branched polyesters with different molecular structures were synthesized via a stepwise polymerization of various epoxy resins with different functional monomers. The chemical structures of polymers were characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The weight-average molecular weights of the prepared polymers were from about 4200 through 9000 g/mol determined by a GPC. The glass transition temperatures of the aliphatic branched polyesters were about from -41 through -14oC, which were primarily dependent on the chemical structures of the polymers. A Carreau-Yasuda model: was proposed to descript the shear-thinning properties of the branched polyesters. Most of the prepared polymers behaved essentially as Newtonian fluids at temperature higher than 70oC, and shear rate less than 1000 1/s. The viscoelastic properties of the branched polymers were further measured. It was found that the shear storage modulus dependent on the frequency was different from that of regular linear polymers. And use Havriliak-Negami model: to describe the dynamic storage modulus and loss modulus dependent on frequency. It is expected that the prepared branched polyesters can be used as toughening agent or plasticizer in dental material.

並列關鍵字

toughness ； branched polyester ； rheology ； thermal analysis

參考文獻

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