多壁碳纳米管官能化对PVDF结晶行为的影响

摘要

采用溶液共混结合溶剂蒸发法制备了聚偏氟乙烯(PVDF)/多壁碳纳米管(MWCNTs)复合薄膜.研究了MWCNTs表面羟基化(MWCNTs-OH)、羧基化(MWCNTs-COOH)、氨基化(MWCNTs-NH2)以及接枝聚甲基丙烯酸甲酯(PMMA)(MWCNTs-g-PMMA)后对PVDF结晶行为的影响.结果表明:官能化前后的MWCNTs均可提高PVDF的β晶型相含量,复合薄膜的熔融温度、结晶温度、结晶度和结晶速度均得到提高.其中含MWCNTs-g-PMMA的复合薄膜中β相含量最高,晶核密度最大,晶体尺寸较小,而结晶度有所降低,但总体都高于纯PVDF;由于MWCNTs-NH2的氨基与PVDF分子链之间的相互偶极作用和氢键协同影响,对PVDF的结晶促进作用最为明显.%Poly (vinylidene fluoride) (PVDF)/functional multi-walled carbon nanotube (MWCNTs) composite film was prepared by solution bending and solvent evaporation method,and then the effects of MWCNTs functionalized with hydroxyl (MWCNTs-OH),carboxyl (MWCNTs-COOH),amino (MWCNTs-NH2) and grafted PMMA (MWCNTs-g-PMMA) on the crystallization behavior of composites were investigated respectively in detail.The experimental results indicated that the percentage of β polymorph in PVDF was increased in presence of pure or functionalized MWCNTs,and the melting temperature,crystallization temperature,crystallinity and crystallization rate were enhanced simultaneously.Composite film containing MWCNTs-g-PMMA showed the highestβ polymorph content and nucleus density,however,the crystal size and crystallinity were decreased compared with other particles.Due to the synergetic effect of hydrogen bonds and dipole polarizations,the crystallization process of PVDF was promoted more effectively when MWCNTs-NH2 was added.