聚苯乙烯改性纤维素纳米晶体对聚甲基丙烯酸甲酯热稳定性的增强作用

采用原子转移自由基聚合(SI-ATRP)在纤维素纳米晶体(CNC)表面接枝聚苯乙烯,并利用傅里叶红外光谱(FTIR)、热重分析仪(TGA)对改性前后的纤维素纳米晶体的化学结构和热稳定性进行了研究。测试结果表明,聚苯乙烯可成功地接枝到纤维素纳米晶体的表面; 纤维素纳米晶体的热分解温度由150 ℃上升到220 ℃,改性后纤维素纳米晶体的热稳定性得到提高。采用溶液浇铸法制备聚甲基丙烯酸甲酯/纤维素纳米晶体复合材料(PMMA/CNC),并利用TGA、透光率测试对复合材料热稳定性和透光率进行了研究。结果表明,当温度达到350 ℃时,PMMA/CNC的热分解温度比纯PMMA提高了近150 ℃, CNC的加入量为1%时,复合材料的透光率为89%,接近纯PMMA的透光率(91%)。聚苯乙烯改性纤维素纳米晶体可用于在保持PMMA透明性的前提下更好地改善PMMA复合材料的热稳定性。

Reinforcement on the thermal stability of poly (methyl methacrylate) of cellulose nanocrystals modified with polystyrene

In order to improve the thermal stability and compatibility with organic materials, cellulose nanocrystals(CNCs)were grafted by polystyrene chains via surface-initiated atom transfer radical polymerization(SI-ATRP). The chemical structure and thermal stability were characterized by the Fourier transform infrared spectroscopy(FTIR)and thermogravimetric analysis(TGA), revealing that polystyrene chains were successfully grafted on the surface of CNCs and the degradation temperature of CNCs increased from 150 ℃ to 220 ℃. Poly(methyl methacrylate)(PMMA)nanocomposites were prepared with the solution casting method and were examined by the TGA and UV-vis spectrophotometer. The remaining rate of PMMA/4%CNC was increased by 100% compared to pure PMMA. The transmittance of the PMMA/1% CNCs approached 89%, which was close to that of the pure PMMA(91%). This research provides a novel method to improve the thermal stability of PMMA/CNC nanocomposite on the premise of remaining the excellent transparency.