X-ray crystallographic structure of meta- and para-dimethyl ester of pyromellitic acid
Data(s) |
1997
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Resumo |
The polycrystalline powder of para- and meta-dimethyl ester of pyromellitic acid (PMDE) have been prepared by fractional crystallization, and their crystal structures have been determined by Wide-Angle X-ray Diffraction (WAXD). Both p-PMDE and m-PMDE was found to be orthorhombic crystal system, and their unit cell parameters a = 0.840 nm, b = 0.707 nm, c = 1.136 nm and a = 1.032 nm; b = 0.835 nm, c = 0.714 nm, respectively. Space group all belongs to P-mmm. p-PMDE has two molecules per unit cell with crystal density 1.388 g . cm(-3), while m-PMDE has two molecules per unit cell with crystal density 1.522 g . cm(-3). Indices of crystal diffraction peaks are also detailed in the present work. The difference in crystal structures between p-PMDE and m-PMDE has thus been used to explain the curing behavior of isomerically pyromellitic dianhydride-based poly(amic ester)s. |
Identificador | |
Idioma(s) |
英语 |
Fonte |
Huang WX;Liu TX;Gao LX;Zhang X;Xu JP;Ding MX.X-ray crystallographic structure of meta- and para-dimethyl ester of pyromellitic acid,CHINESE JOURNAL OF POLYMER SCIENCE,1997,15(1):40-49 |
Palavras-Chave | #AROMATIC POLYIMIDES #IMIDIZATION #DIANHYDRIDE #PRECURSORS |
Tipo |
期刊论文 |