Chen Jirui, Huang Wentao, Chen Yifan, Zhou Zenan, Liu Huan, Zhang Wenbiao, Huang Jingda
College of Chemistry and Materials Engineering, Zhejiang A&F University, Hangzhou 311300, China.
China Bamboo Charcoal Museum, Lishui 323300, China.
Polymers (Basel). 2022 Mar 25;14(7):1337. doi: 10.3390/polym14071337.
To improve on the poor strength and flame retardancy of a chitosan (CS)-based functional film, cellulose nanofiber (CNF) was taken as the reinforced material and both ammonium polyphosphate (APP) and branched polyethyleneimine (BPEI) as the flame-retardant additives in the CS matrix to prepare the CS/CNF/APP/BPEI composite film by simple drying. The resulting composite film showed good mechanical strength, with a tensile strength reaching 71.84 Mpa due to the high flexibility of CNF and the combination of CS, CNF and BPEI through strong hydrogen bonding interactions. The flame retardant-performance of the composite film greatly enhanced the limit oxygen index (LOI), up to 32.7% from 27.6% for the pure film, and the PHRR intensity decreased to 28.87 W/g from 39.38% in the micro-scale combustion calorimetry (MCC) test due to the ability of BPEI to stimulate the decomposition of APP, releasing non-flammable gases such as CO, N, NH, etc., and forming a protective phosphating layer to block the entry of O. Based on the good flame retardancy, mechanical strength and transparency, the CS/CNF/APP/BPEI composite film has a great potential for future applications.
为改善壳聚糖（CS）基功能膜较差的强度和阻燃性，以纤维素纳米纤维（CNF）作为增强材料，并将聚磷酸铵（APP）和支化聚乙烯亚胺（BPEI）作为CS基质中的阻燃添加剂，通过简单干燥制备CS/CNF/APP/BPEI复合膜。由于CNF的高柔韧性以及CS、CNF和BPEI通过强氢键相互作用结合，所得复合膜显示出良好的机械强度，拉伸强度达到71.84 Mpa。复合膜的阻燃性能极大地提高了极限氧指数（LOI），从纯膜的27.6%提高到32.7%，并且在微型燃烧量热法（MCC）测试中，热释放速率峰值（PHRR）强度从39.38 W/g降至28.87 W/g，这是由于BPEI能够促进APP的分解，释放出CO、N、NH等不可燃气体，并形成保护性磷化层以阻止O进入。基于良好的阻燃性、机械强度和透明度，CS/CNF/APP/BPEI复合膜在未来应用中具有巨大潜力。
