Studies on Comb-like Polymers. 1. Poly(octadecylethylene)
Studies on Comb-like Polymers. 1. Poly(octadecylethylene)
复制标题
梳状聚合物的研究。
DOI：
10.1021/ma60073a002
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发表时间：
1980
期刊：
影响因子：
5.5
通讯作者：
G. Benetti
中科院分区：
文献类型：
--
作者：
P. Magagnini;F. Andruzzi;G. Benetti
The thermal properties of different samples of poly (octadecylethylene) were determined and their crystalline structures were studied by X-ray scattering. The atactic-rich, ether-soluble fraction melts sharply at 58 C and has a structure characterized by disordered main chains and crystallized side chains. The isotactic-rich fraction, probably containing blocks of atactic polymer, can be obtained in different crystalline modifications according to the thermal treatment. Asample obtained by quenching from the melt shows an X-ray diffraction diagram very similar to that of the atactic material. It also melts at a temperature of ca. 58 C. However, on further heating it undergoes a recrystallization which is followed by a second melting at ca. 83 C. The samples subjected to thermal treatments capable of improving the crystallinity are of two main types. Both types have a structure characterized by main chains confined to planes regularly spaced. The melting point of the isotactic polymer varies slightly with thermal history (between about 75 and 85 C) and is considerably higher thanthat ofthe atactic polymer (58 C). The two materials form incompatible phases.Since the early discovery by Rehberg and Fisher, 1 Kaufman et al., 2 and Wiley and Brauer3 that polymers containing long paraffinic side groups give rise to side-chain crystallization, many articles have appeared in the litera-ture describing the structure, the properties, and the ap-plications of these so-called comb-like polymers. The matter has been reviewed recently by Platé and Shibaev. 4 However, as has been made evident in a recent publi-cation by Morawetz and collaborators, 5 the principles governing side-chain crystallization in these materials are more complicated than thought before and are far from being fully understood. One of the problems is the influ-ence (if any) exerted by the stericconfiguration of the backbone upon the crystalline structure and the properties of these polymers. 4 Moreover, there is no agreement on whether the main chains can participate in the crystal lattice. 6, 7 Only for isotactic long side-chain poly (alkyl-ethylenes) is there general agreement that the backbone, chains may assume a regular conformation in the crys-talline state.
