Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/3505
標題: Swelling and biodegradation of acrylic acid-containing dextran hydrogels
丙烯酸聚葡萄醣水膠之膨潤性質與生物分解性質的探討
作者: 謝婷
關鍵字: 聚葡萄醣水膠;非高斯行為;生物分解性;酸鹼敏感性;平衡膨潤
出版社: 化學工程學系
摘要: 
Dextran hydrogels were obtained by radical copolymerization of methacrylated dextran (MA-dextran) with acrylic acid (AAc) using ammonium peroxydisulfate (APS) and N,N,N',N'- tetramethylethylenediamine (TMEDA) as an initiation system. The incorporated amount and the dissociation degree of AAc in hydrogels were determined by FTIR-ATR. The experimental data were exploited to evaluate the total ion concentration difference between inside and outside the hydrogel (ionic osmotic pressure). The changes of ionic osmotic pressure were well consistent with the equilibrium swelling behavior of hydrogels. The elastic retractile force of swollen hydrogel was evaluated by measuring the modulus of elasticity in mechanical compression. The results revealed that the swelling of hydrogels appeared in non-Gaussian manner.
Enzymatic degradation of dextran hydrogels with different AAc contents was monitored by residual weight ratio, degree of swelling, and elastic modulus measurements. Hydrogels without AAc was only surface- degraded in the presence of dextranase while the degradation behavior of hydrogels with increased AAc content deviated from the surface degradation mechanism to a more significant extent.

將glycidyl methacrylate (GMA)與dextran進行轉酯化反應,形成MA-dextran,然後與acrylic acid (AAc)進行自由基共聚合反應,形成具酸鹼敏感性的dextran水膠。我們以FTIR-ATR檢測水膠中AAc的含量,並測量不同AAc含量之水膠在不同pH值、不同離子強度的溶液下實際的解離程度,而後以此實驗值去計算水膠內外之離子濃度差及離子造成之化學位能差。研究中我們發現離子所造成之化學位能差對水膠膨潤行為的影響最大,但隨著離子強度的增加,此效應也會降低。另外也發現因為離子對水膠膨潤行為的影響較大,所以隨著pH值的增加,水膠中解離的AAc愈多,高分子與溶劑混合造成之化學位能差反而會減少。此外我們還測量不同AAc含量之水膠在不同pH值、不同離子強度的狀態下其彈性模數(G)的變化。從實驗中發現水膠在低離子強度的溶液下,其G值會比高離子強度之G值還高,而且會隨著pH值而呈現先降後升的趨勢,因此此水膠彈性力的變化應不屬於高斯分布之行為,也因此在以理論分析水膠之膨潤行為時會產生偏差,而且隨著水膠愈膨潤,其偏差就愈大。實驗的第二個部分則是探討含AAc之dextran水膠的生物分解性。我們用dextranase對水膠進行酵素分解。實驗中測試了水膠分解時多項的性質變化,包括水膠殘餘率的變化、膨潤程度的變化、彈性模數的變化、及分解溶液中oligosacchrides含量的變化。我們發現隨著水膠內 AAc含量的增加,水膠的交聯密度愈高,要達到完全分解的時間就愈長。而且隨著AAc含量的不同其分解的行為也會不同。不含AAc之水膠的分解行為近似於surface degradation,而後隨著AAc含量的增加,水膠之分解行為與表面分解的偏差就愈明顯。
URI: http://hdl.handle.net/11455/3505
Appears in Collections:化學工程學系所

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