聚乙烯醇-海藻酸钙复合材料制备及性质

Preparation of PVA-alginate-Ca blends

目的 :以聚乙烯醇 (PVA)和海藻酸钠为主要组分 ,通过对两种聚合物的分步交联 ,获得具有交联结构的PVA -海藻酸钙复合材料 .方法 :探讨了PVA和海藻酸钠不同配比 ,交联剂氯化钙不同浓度对材料性能的影响 ,从中选择出了PVA与海藻酸钠的较佳配比为 4∶1和交联剂氯化钙的适宜浓度为 2 % ;用原子吸收光谱测定了材料中钙的含量 ;用扫描电镜观察材料的组织形态 .结果 :所制得的PVA -海藻酸钙交联复合物 ,外观均一 ,光洁平滑 ,柔韧具弹性 ,呈乳白色 ,湿态下扯断伸长率为 350 % ,拉伸强度为 2 0MPa ,含水率为 77% .结论 :PVA和海藻酸钠通过交联反应形成PVA -海藻酸钙复合物后 ,两者的玻璃化温度向彼此接近的方向发生了内移 ,在一定程度上发生了分子水平的互溶 。

Aim: To prepare polymer PVA-alginate-Ca with network structure from PVA and alginate-Ca. Methods: Different ratios between PVA and alginate-Na, different weight percentages in glutaraldhyde and different concentration of CaCl 2 in connection with the preparation of PVA-alginate-Ca were studied. These are three factors which effect the properties of PVA-alginate-Ca.Results: The optimun conditions for the preparation of the polymer materials were selected, the ratio between the contents of PVA and alginate-Na being 4∶1 and CaCl 2 concentration 2%. SEM proved that the morphology of PVA-alginate-Ca was network structure. PVA-alginate-Ca modulus curve was observed by dymamic viscoelastometer. After crosslinking, Tg PVA and Tg alginate shifted closer to each other.Conclusion: The tensile strength of the polymer obtained was 20MPa, water content>77%, and elasticity >350%. PVA and alginate-Ca were compatibly blended on molecular level. CaCl 2 was a crosslin king agent changing alginate-Na to alginate-Ca, PVA and alginate-Ca network polymer was obtained.[