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本文用氢谱宽线固体NMR技术研究了聚甲基丙烯酸甲酯(PMMA)和苯乙烯-丙烯腈共聚物(SAN)混合体系不稳相分离初期阶段,得到了在分相过程中弛豫谱的变化规律,测定了相分离增长速率。结果指出:随着退火时间的增加,两相体系形成;大分子扩散方式是由浓度低的区域向浓度高的区域扩散,扩散系数为负值;相分离增长速率的数量级与用光散射研究的结果相同;分子相互作用的相关距离为46.5nm。
In this paper, the initial phase of the unsteady phase separation of polymethylmethacrylate (PMMA) and styrene-acrylonitrile copolymer (SAN) blends was studied by using wideband solid-state NMR spectroscopy, and the relaxation spectra The variation of phase separation was measured. The growth rate of phase separation was measured. The results show that the two-phase system is formed with the increase of annealing time. The diffusion of macromolecules diffuses from the low concentration region to the high concentration region, and the diffusion coefficient is negative. The magnitude of the phase separation growth rate is similar to that of the light scattering The result was the same; the relative distance of the molecular interaction was 46.5 nm.