梳状高分子烷基侧链构象和堆积结构的红外光谱研究  

TRANSITION INVESTIGATION ON THE CONFORMATION AND PACKING STRUCTURES OF ALKYL SIDE CHAINS IN COMBLIKE POLYMERS WITH FT-IR SPECTROSCOPY

作　　者：石海峰[1] 赵莹[1] 谢保全[1] 王笃金[1] 徐端夫[1] 

机构地区：[1]中国科学院化学研究所高分子物理与化学国家重点实验室北京分子科学国家实验室,北京100080

出　　处：《高分子学报》2008年第3期266-270,共5页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号50403026;50573086)资助项目

摘　　要：以正十九烷和两种接枝烷基链的梳状高分子N-十八烷基聚乙烯亚胺(PEI18C)、N-十八烷基聚对苯甲酰胺(PBA18C)为研究对象,利用红外光谱对处于受限和自由状态的烷基链的构象和堆积结构随温度的变化进行了对比研究.结果表明,处于受限和自由状态的烷基链的构象排列和堆积结构及其转变行为不同,且受限于柔性PEI主链和刚性PBA主链的烷基链也不相同.从主链刚性的角度,探讨了影响烷基侧链构象和堆积结构的原因.The temperature-induced variation of the conformational behavior and the packing structure of alkylchains in n-nonadecane, N-octadecylated polyethyleneimine （PEI18C） and N-octadecylated poly （p-benzamide） （PBA18C） were investigated with FT-IR spectroscopy and other techniques. The main aim is to in-depth understand the specific aggregation structure of alkyl side chains in the comblike polymers. N-alkylation reactions onpolyethyleneimine （PEI） and poly （p-benzamide） （PBA） backbone were carried out in homogenous solutions composed of octadecyl bromide and polymer substrate. According to the results of nuclear magnetic resonance （NMR） and elemental analysis measurements, the N-substitution degree was obtained, i. e. 47% for PEI18C and 97% for PBA18C,respectively. The relative intensity of the conformation bands of methylene group at 1463 cm-and 1470 cm was utilized to investigate the conformation transition behavior of PEI18C and nonadecane in the heating process .The results indicated that the octadecyl chains of PEI18C exhibited different conformation transition process compared with those of nonadecane. The variation of the rocking bands of methylene groups implied that the ordered packing structure of the octadecyl chains in PEI18C had much more slower transition velocity and complicated variation process than those of pure nonadecane. Based on the differences among the above mentioned IRspectral bands of PEI18C, PBA18C and nonadecane, the ordered degree of the conformation and the packing structure of the alkyl chains were compared. The alkyl side chains of PEI18C and PBA18C were found to pack into aggregation structure with different ordered degree, originating from the confinement and rigidity difference of the main chain. After melting, unlike nonadecane, the alkyl chains of PEI18C and PBA18C can not get into totally random amorphous state. The above results reveal that the conformational changes, packing structure of CH2 groupsand their phase transition behavior in the confined

关 键 词：梳状高分子 烷基链 结构转变 红外光谱 

分 类 号：O631[理学—高分子化学]