壳聚糖-聚乙烯醇复合水凝胶溶胀度及其生物相容性 化工与环境工程----- 外文翻译.doc

2.2.1 Chitosan and PVA solution preparation
Briefly, PVA hydrogels were prepared by fully dissolving 5.0g of polymer powder without further purification in 100 ml of Milli-Q water, under magnetic stirring, at temperature of 75 ± 2℃ (solution A), as previously reported by our group [7–9]. PVA 5% solution was let to cool down to room temperature and the pH was corrected to (2.00 ± 0.05) with 1.0 M HCl (Sigma). Chitosan hydrogels (Chi) were produced in a similar procedure by fully dissolving 2.5g in 250.0ml of Milli-Q water with 2% of CH3COOH (Sigma),under magnetic stirring for 48 h (solution B).

2.2.2 Chitosan, PVA and blends films preparation
Different quantities of PVA (solution A) were added into the 1.0% chitosan solution (solution B) to obtain chitosan/PVA mass ratios of (0:1), (1:3), (1:1), (3:1), and (1:0) and pH was corrected to (4.00 ± 0.05) with 1.0 M NaOH solution. The mixture was kept under stirring for 5 min until the PVA and chitosan completely formed a clear solution. Then, the crosslinker reagent (GA) was slowly added under constant stirring. The final concentration of GA in the gel solution precursors was 1% and 5% (wt%). Further in thesequence, the solution was poured into plastic moulds and let drying for 72–120 h at room temperature, and finally dried at 40℃ for 24 h (constant weight). Chitosan/PVA samples chemically crosslinked were identified by (X:Y:Z) that is, X as chitosan content, Y as PVA content, and Z as GA (wt%). For instance, sample identified as Chi/PVA/GA (1:3:1) represents the following proportion of reagents: 25% chitosan, 75% PVA and crosslinked with 1.0% GA (wt%). The dried gel was stored in a desiccator before all sub-sequent characterization procedures.



2.2.1壳聚糖溶液和PVA溶液制备
首先，聚乙烯醇水凝胶的制备，是先称5.0g聚乙烯醇粉末使其在100ml纯净水中进一步完全溶解，同时在电磁搅拌下，温度控制75±2℃（溶液A），就像我们团队之前的报道所示。[7-9]。5％的聚乙烯醇完全溶解后，让其冷却到室温和用1.0 M盐酸（ ）把pH值控制在（2.00±0.05）。壳聚糖水凝胶（壳聚糖）制备采用相似的步骤，称2.5g壳聚糖在250ml 2％的醋酸溶液（ ）中，电磁搅拌48小时（溶液B）。

2.2.2壳聚糖和聚乙烯醇复合水凝胶制备
用不同量的聚乙烯醇溶液（溶液A）加入到1.0％的壳聚糖溶液（溶液B）获得以下几种壳聚糖/聚乙烯醇水凝胶，分别质量比为（0:1），（1:3 ），（1:1），（3:1）和（1:0）和用1.0M氢氧化钠溶液把pH值调节在（4.00±0.05）。将该混合物继续搅拌5分钟，直到聚乙烯醇和壳聚糖完全形成了清澈溶液。然后，缓慢加入交联剂（戊二醛），并不断搅拌。在溶液凝胶初期，戊二醛的最后浓度为1％和5％（质量分数％）。随着进一步反应，溶液不断塑化，接着在室温下其让干燥72至120 h，最后在40℃干燥24小时（恒重）。壳聚糖-聚乙烯醇复合水凝胶样品的化学交联反应产生凹痕已确定为（X： Y： Z）三种因素，X为壳聚糖的含量，Y为聚乙烯醇的含量，Z为戊二醛（质量分数%）。例如，样品组成确定为壳聚糖/聚乙烯醇/戊二醛=（1:3:1）,则：25％的壳聚糖，75％聚乙烯醇和1.0％（质量分数％）戊二醛。干凝胶储存在干燥器之前，要记录样品每一个特征。