NMR study of the morphology of polystyrene linear/microgel blends

被引:10
|
作者
McGrath, KJ
Roland, CM
Antonietti, M
机构
[1] USN, Res Lab, Div Chem, Washington, DC 20375 USA
[2] Max Planck Inst Colloids & Interfaces, D-14513 Teltow, Germany
关键词
D O I
10.1021/ma000951x
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
The morphology of blends of polystyrene (PS) microgels with linear PS were studied using NMR spectroscopy. Three techniques were employed to assess the intimacy of mirdng: isothermal;cross-polarization/magic angle-spinning (CP/MAS) dipolar dephasing C-13 NMR, temperature-dependent 13C CP/ MAS NMR, and one-pulse H-1 MAS NMR. The experimental data reveal that linear PS can penetrate: the core of soft microgels, whose network strands are substantially larger than the linear chains. However when the microgel is highly cross-linked, such penetration is prevented. These results are in accord with Flory-Huggins swelling theory. Blends of linear PS with highly cross-linked microgels yield thermodynamically stable morphologies, in which the components are molecularly dispersed, yet segmental contacts are virtually absent. Such a phase morphology is novel and cannot be obtained with-conventional polymer blends.
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页码:8354 / 8360
页数:7
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