天然多羟基化合物改性聚氨酯纳米水分散液的合成及膜性能表征

Study on modification of waterborne polyurethane nano-dispersions with hydroxyl compound

以葡萄糖(glucose)为交联扩链剂,采用预聚体分散法,制备了系列不同葡萄糖含量的改性聚氨酯纳米水分散液(GWPU)。研究了葡萄糖用量对GWPU乳液及膜性能的影响。采用FT-IR、DLLS、TEM、XRD、TGA、AFM、水接触角、力学性能测试等手段对聚合物乳液性能及膜结构进行了表征。结果表明,葡萄糖成功嵌入聚氨酯;乳液粒径随葡萄糖用量的增加而增大,分布均匀,呈圆球状;改性后聚氨酯热稳定性提高,为两步分解;葡萄糖的引入使得聚合物的硬段含量、薄膜的粗糙度增加,抗水性增强;改性后产物为非晶态聚合物,分子结构规整性较差但材料柔韧性较好;拉伸强度随葡萄糖用量的增加而增大,而断裂伸长率则降低;吸水率随着葡萄糖用量的增加而降低。当m(glucose)=4%时,拉伸强度、断裂伸长率、吸水率及水接触角分别为16.9MPa、276.5%、5.7%及97.5°。

The waterborne polyurethane nano-dispersions modified with glucose （GWPU） were synthesized via pre-polymer dispersion. The effects of the amounts of cross-linking agent, glucose, on the synthesis of GWPU were studied. The structure and properties were characterized by FT-IR, DLLS, TEM, TEM, TG, XRD, AFM, water contact angle and mechanical properties. Results indicated that the glucose dispersed well as an incorporated state in the polyurethane phase measured by FT-IR. The morphology of the particle was uniform spherical structure and its size increased with the increasing glucose content of GWPU. A distinct improvement in the thermal stability of the resulting polymer with the crosslinking agent was observed compared with the unmodified polyurethane by TG, as a two-step thermal decomposition. AFM indicated that the roughness of solidified WPU films increased when modified by glucose, resulting in water repellence functions. The crystallinity of the resulting polymer, detected in XRD, was low, which indicated that the resulting polymer had superior flexibility. The water swelling decreased with increasing of glucose content having optimum glucose contents at 4wt~ with 5.7~, and it increased slightly with further increase of glucose contents. The tensile strength increased, while the elongation at break decreased. The optimum tensile strength and elongation at break were 16.9MPa and 276.5% when the glucose content was 4wt %. And the water contact angle was 97.5%.