Transition investigation on the conformation and packing structures of alkyl side chains in comblike polymers with FT-IR spectroscopy

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	Transition investigation on the conformation and packing structures of alkyl side chains in comblike polymers with FT-IR spectroscopy
	Shi Haifeng; Zhao Ying; Xie Baoquan; Wang Dujin; Xu Duanfu
刊名	ACTA POLYMERICA SINICA
	2008-03-01
期号	3 页码:266-270
关键词	Comblike Polymers Alkyl Side Chains Conformational Transition Ft-ir Spectroscopy
ISSN号	1000-3304
英文摘要	The temperature-induced variation of the conformational behavior and the packing structure of alkyl chains 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 on polyethyleneimine (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(-1) and 1470 cm(-1) 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 IR spectral 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 CH, groups and their phase transition behavior in the confined and non-confined state are obviously different in all the above three cases, which might be attributed to the different mobility of alkyl side chains under the aforementioned confinement condition. Moreover, the different main-chain structural characteristic i.e. flexibility or rigidity, also has extensive influence on the conformational changes and packing structure of alkyl groups grafted on the PEI and PBA backbone. The main reason can be ascribed to the different conformation adjustment ability of the PEI and PBA backbones.
语种	英语
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000254640400010
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/63179]
专题	中国科学院化学研究所
通讯作者	Shi Haifeng
作者单位	Chinese Acad Sci, Inst Chem, State Key Lab Polymer Phys & Chem, Beijing Natl Lab Mol Sci, Beijing 100080, Peoples R China
推荐引用方式 GB/T 7714	Shi Haifeng,Zhao Ying,Xie Baoquan,et al. Transition investigation on the conformation and packing structures of alkyl side chains in comblike polymers with FT-IR spectroscopy[J]. ACTA POLYMERICA SINICA,2008(3):266-270.
APA	Shi Haifeng,Zhao Ying,Xie Baoquan,Wang Dujin,&Xu Duanfu.(2008).Transition investigation on the conformation and packing structures of alkyl side chains in comblike polymers with FT-IR spectroscopy.ACTA POLYMERICA SINICA(3),266-270.
MLA	Shi Haifeng,et al."Transition investigation on the conformation and packing structures of alkyl side chains in comblike polymers with FT-IR spectroscopy".ACTA POLYMERICA SINICA .3(2008):266-270.