Molecular Modeling and Large-Angle X-ray Scattering Studies of the Structure of Semicrystalline Poly[bis(phenoxy)phosphazene]
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- 作者：Ruggero Caminiti ; Mario Gleria ; Kenny B. Lipkowitz ; Giuseppe M. Lombardo ; and Giuseppe C. Pappalardo
- 刊名：Chemistry of Materials
- 出版年：1999
- 出版时间：June 1999
- 年：1999
- 卷：11
- 期：6
- 页码：1492 - 1497
- 全文大小：112K
- 年卷期：v.11,no.6(June 1999)
- ISSN：1520-5002
文摘
The structure and conformation of semicrystalline poly[bis(phenoxy)phosphazene] (PBPP)was studied using molecular mechanics including ad hoc quantum mechanically derivedforce field (FF) parameters, in combination with the energy-dispersive X-ray diffraction(EDXD) technique. The atom-atom radial distribution function (RDF) curves were calculatedfor the various models of backbone conformations and for the structure in the crystalline
-form of PBPP. On the basis of comparison between theoretically calculated RDFs withthe RDF obtained from the EDXD experiment, a model was proposed. The structural featuresof this model are (i) the polymer backbone adopts a low-energy, planar, trans-cis [TC]nconformation, (ii) each chain is, on average, comprised of 16 monomeric units, and (iii) theunit cell may be restricted to contain two such chains running antiparallel to each otherand with their backbones aligned parallel to the (1, 1, 0) Miller plane. The results demonstratethe capability of the combined use of computational chemistry (molecular modeling) andX-ray diffraction techniques such as EDXD to provide insights, otherwise experimentallyinaccessible, into the conformational and structural features of semicrystalline polyphosphazenic materials.
-form of PBPP. On the basis of comparison between theoretically calculated RDFs withthe RDF obtained from the EDXD experiment, a model was proposed. The structural featuresof this model are (i) the polymer backbone adopts a low-energy, planar, trans-cis [TC]nconformation, (ii) each chain is, on average, comprised of 16 monomeric units, and (iii) theunit cell may be restricted to contain two such chains running antiparallel to each otherand with their backbones aligned parallel to the (1, 1, 0) Miller plane. The results demonstratethe capability of the combined use of computational chemistry (molecular modeling) andX-ray diffraction techniques such as EDXD to provide insights, otherwise experimentallyinaccessible, into the conformational and structural features of semicrystalline polyphosphazenic materials.