Solid-state NMR study of structure, size and dynamics of domains in hybrid siloxane networks

被引:32
作者
Brus, J [1 ]
Dybal, J [1 ]
机构
[1] Acad Sci Czech Republ, Inst Macromol Chem, CR-16206 Prague 6, Czech Republic
关键词
hybrid siloxane networks; solid state NMR; spin diffusion;
D O I
10.1016/S0032-3861(99)00741-7
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Structure, size and dynamics of domains of hybrid siloxane networks prepared by copolymerization of tetraethoxysilane (TEOS) and dimethyl(diethoxy)silane (DMDEOS) were studied by several techniques of solid-state H-1 and Si-29 NMR spectroscopy as well as by ab initio quantum chemical calculations. T-1 rho(H-1) relaxation times, dipolar dephasing and spin diffusion experiments confirmed the existence of nano-heterogeneous system with random, bicontinuous morphology. The size of domains of TEOS homopolymer is about 1.3-2.8 nm, the size of copolymer phase bring larger, ca. 4.0-6.8 nm. Quantum chemical ab initio calculations of geometry and the principal values of Si-29 NMR chemical shift tensor and the isotropic chemical shift confirmed our structural predictions that copolymers with polycyclic structure units are formed. The accord of calculated values with those experimentally determined was sufficiently good. (C) 2000 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:5269 / 5282
页数:14
相关论文
共 47 条
[1]   CROSS POLARIZATION AND MAGIC ANGLE SAMPLE SPINNING NMR-SPECTRA OF MODEL ORGANIC-COMPOUNDS .3. EFFECT OF THE C-13-H-1 DIPOLAR INTERACTION ON CROSS POLARIZATION AND CARBON-PROTON DEPHASING [J].
ALEMANY, LB ;
GRANT, DM ;
ALGER, TD ;
PUGMIRE, RJ .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1983, 105 (22) :6697-6704
[2]  
BABONNEAU F, 1994, NEW J CHEM, V18, P1065
[3]   DENSITY-FUNCTIONAL THERMOCHEMISTRY .3. THE ROLE OF EXACT EXCHANGE [J].
BECKE, AD .
JOURNAL OF CHEMICAL PHYSICS, 1993, 98 (07) :5648-5652
[4]   CHARACTERIZATION OF PDMS MODEL JUNCTIONS AND NETWORKS BY SOLUTION AND SOLID-STATE SI-29 NMR-SPECTROSCOPY [J].
BESHAH, K ;
MARK, JE ;
ACKERMAN, JL ;
HIMSTEDT, A .
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, 1986, 24 (06) :1207-1225
[5]  
*BIOSYM MSI, 1995, INS 2 VERS 95 0 MOL
[6]   PROTON NMR-STUDY OF DEHYDRATION OF THE SILICA-GEL SURFACE [J].
BRONNIMANN, CE ;
ZEIGLER, RC ;
MACIEL, GE .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1988, 110 (07) :2023-2026
[7]   POPULATIONS OF OLIGOMERS IN SOL-GEL CONDENSATION [J].
BRUNET, F ;
CABANE, B .
JOURNAL OF NON-CRYSTALLINE SOLIDS, 1993, 163 (03) :211-225
[8]   SOL-GEL POLYMERIZATION STUDIED THROUGH SI-29 NMR WITH POLARIZATION TRANSFER [J].
BRUNET, F ;
CABANE, B ;
DUBOIS, M ;
PERLY, B .
JOURNAL OF PHYSICAL CHEMISTRY, 1991, 95 (02) :945-951
[9]   Copolymerization of tetraethoxysilane and dimethyl(diethoxy)silane studied by 29Si NMR and ab initio calculations of 29Si NMR chemical shifts [J].
Brus, J ;
Dybal, J .
POLYMER, 1999, 40 (25) :6933-6945
[10]  
CHIN YH, 1994, MAGN RESON CHEM, V53, P32