STRUCTURAL STUDIES OF POLY(ETHYLENIMINE) .3. STRUCTURAL CHARACTERIZATION OF ANHYDROUS AND HYDROUS STATES AND CRYSTAL-STRUCTURE OF THE HEMIHYDRATE
STRUCTURAL STUDIES OF POLY(ETHYLENIMINE) .3. STRUCTURAL CHARACTERIZATION OF ANHYDROUS AND HYDROUS STATES AND CRYSTAL-STRUCTURE OF THE HEMIHYDRATE
复制标题
DOI：
10.1021/ma00236a009
复制
发表时间：
1983-01-01
期刊：
影响因子：
5.5
通讯作者：
TADOKORO, H
中科院分区：
文献类型：
--
作者：
CHATANI, Y;KOBATAKE, T;TADOKORO, H
对聚乙烯亚胺吸收水蒸气的一系列X射线研究表明，除了倍半水合物和二水合物之外，还存在半水合物(-CH2CH2NH--0.5 H2O) n 。因此，可以断言，随着水含量的增加，无水物转化为半水合物，随后转化为倍半水合物，最后转化为二水合物。半水合物晶体是单斜晶系，晶胞尺寸a= 1.089 nm，b= 0.952 nm，c（纤维轴）= 0.731 nm，和/3= 127.6。空间群为C2/c，晶胞包含八个单体单元（四个链）和四个水分子。与倍半水合物和二水合物一样，聚合物链完全延伸。半水合物中的所有氢键都是NH-O或NH-0类型：与其他两种水合物相比，不存在水-水氢键网络。对无水物和三种水合物中的氢键模式进行了总结和讨论。还提供了聚氮丙啶的各种 X 射线衍射曲线，用于鉴定所讨论样品的晶型。之前对线性聚氮丙啶 (PEI) 的 X 射线研究 1-3 表明，这种聚合物的吸湿特性可归因于结晶水合物的形成，其中“结晶水”按化学计量存在。实际上，PEI 二水合物含有大量的水，几乎与 PEI 本身的重量相当。根据这些研究，该聚合物
A series of X-ray studies on the absorption of water vapor by poly (ethylenimine) revealed the existence of the hemihydrate,(-CH2CH2NH--0.5 H2O) n, besides the sesquihydrate and the dihydrate. It is therefore asserted that the anhydrate transforms into the hemihydrate, subsequently the sesquihydrate, and finally the dihydrate with increasing water content. The hemihydrate crystals are monoclinic, with cell dimensions a= 1.089 nm, b= 0.952 nm, c (fiber axis)= 0.731 nm, and/3= 127.6. The space group is C2/c, and the unit cell contains eight monomeric units (four chains) and four water molecules. The polymer chains are fully extended as in both the sesquihydrate and the dihydrate. All hydrogen bonds in the hemihydrate are of the NH—O or N—H-0 type: there exists no water-water hydrogen bond network, in contrast to the other two hydrates. The modes of hydrogen bondings in the anhydrate and the three hydrates are summarized and discussed. A varietyof X-ray diffraction curves of poly (ethylenimine) are also presented for the use of identification of the crystal form (or forms) of a sample in question.Previous X-ray studies1-3 on linear poly (ethylenimine)(PEI) have revealed that the hygroscopic feature of this polymer is attributable to the formation of crystalline hydrates in which “water of crystallization” exists stoichiometrically. In practice, the PEI dihydrate contains a large quantity of water almost comparable to the weight of PEI itself. According to those studies, thepolymer