改性埃洛石纳米管中甲基丙烯酸甲酯的ARGET ATRP聚合

摘要

受限空间内进行自由基聚合有望获得特殊性能的产物或新材料.采用4种硅烷偶联剂KH151、KH550、KH560、KH570分别对埃洛石纳米管(HNTs)进行了改性,将改性埃洛石纳米管(HNTs-M)作为"受限空间",在其内部进行甲基丙烯酸甲酯(MMA)的电子转移活化再生催化剂原子转移自由基聚合反应(ARGET ATRP).通过XRD、TEM、SEM、FTIR、TGA、N2吸附/脱附、GPC、1H NMR等测试方法对HNTs-M、HNTs-M/PMMA复合材料及其孔道内PMMA进行了分析表征.结果表明,改性后和聚合后的HNTs比表面积、孔容及孔径依次降低,且晶型结构没有被破坏,孔道内的PMMA以无定形结构形式存在.与常规聚合所得的PMMA相比,孔道内部聚合所得的PMMA的分子量、热稳定性、等规立构含量有所提高,且分子量分布仍然较窄,但间规立构含量有所降低.%Free radical polymerization within confined space is expected to obtain products with special properties or new materials. Halloysite nanotubes(HNTs)were modified by vinyl triethoxylsilane (KH151),3-aminopropyltriethoxysilane (KH550),3-glycidoxypropyl-trimethoxysilane(KH560), and 3-methacryloxypropyltrimethoxysilane(KH570),respectively,and used as "confined space" to polymerize methyl methacrylate by activators regenerated by electron transfer for atom transfer radical polymerization(ARGET ATRP). The modified HNTs(HNTs-M),HNTs-M/PMMA composites and PMMA obtained from the channels of HNTs-M were characterized by X-ray powder diffraction (XRD),transmission electron microscope(TEM),scanning electron microscopy(SEM),nitrogen adsorption measurements,gel permeation chromatography(GPC),fourier transform infrared spectroscopy(FTIR),thermogravimetry analysis(TGA),and hydrogen nuclear magnetic resonance (1H NMR),respectively. The results showed that the specific surface area,pore volume and pore size of HNTs,HNTs-M and HNTs-M/PMMA composites were decreased in turn,but there was no change in crystal structure,indicating that the PMMA in the channels was of amorphous morphology. Compared with conventional polymerization of MMA,the PMMA in channels possessed higher molecular weight,thermostability,and isotactic structure content and narrow molecular weight distribution,but decreased syndiotactic structure content.