接枝改性CNF增强聚丙烯酸酯复合膜制备及性能

Preparation and Properties of Polyacrylate Composite Membranes Reinforced by Graft-modified Cellulose Nanofibrils

采用2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)氧化法结合均质处理制备得到纤维素纳米纤维(CNF),然后以丙烯酸对CNF进行接枝改性,将接枝改性的CNF用于增强聚丙烯酸酯膜。测试表征了接枝前后CNF的结构和性能,并利用动态热机械分析、热重分析、吸水率和拉伸性能测试研究了不同改性CNF含量的聚丙烯酸酯复合膜性能。结果表明,CNF表面成功接枝了丙烯酸,在聚丙烯酸酯中添加改性CNF后,复合膜的热稳定性和强度提高,随着改性CNF质量分数从0%增大到5%,拉伸强度从3.5 MPa增大到9.2 MPa,断裂伸长率在改性CNF质量分数为0.1%时达到最大,为783%。此外,复合膜的光透过率随着改性CNF含量增加而下降,改性CNF的加入导致复合膜吸水率升高。当改性CNF质量分数为0.1%时,复合膜既具有良好的力学性能,又具有较高的光透过率和较低的吸水率。

Cellulose nanofibrils(CNF)were prepared via the TEMPO oxidation,followed by an appropriate homogenization.The synthesized CNF was modified by the grafting modification with acrylic acid and then used to enhance polyacrylate membrane.The structure and performance of CNF before and after grafting modification were characterized,and the performances of the polyacrylate composite membranes with the different modified CNF contents were investigated by dynamic mechanical analysis,thermogravimetric analysis,water absorption and tensile performance tests.The results indicate that the surface of CNF is successfully grafted with polyacrylic acid.The incorporation of modified CNF improves the thermal stability and mechanical strength of the composite membrane.With the content of the modified CNF increases from 0wt%to 5wt%,the tensile strength of the composite membrane is increased from 3.5 MPa to 9.2 MPa,and the elongation at break reaches maximum(783%)when the content of the modified CNF is 0.1wt%.In addition,the modified CNF decreases the transparency of the composite membrane,and the water absorption is increased as the increase in the modified CNF content due to its abundant hydroxyl groups exposed on the surface.When the content of the modified CNF is 0.1wt%,it can effectively enhance the mechanical properties of the composite membrane,and the obtained membrane also exhibits relatively high transparency and low water absorption.