Phase Separation and Viscoelastic Behavior of Semicompatible Polymer Blends: Poly(vinylidene fluoride)/Poly(methyl methacrylate) System
Phase Separation and Viscoelastic Behavior of Semicompatible Polymer Blends: Poly(vinylidene fluoride)/Poly(methyl methacrylate) System
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半相容聚合物共混物的相分离和粘弹性行为：聚偏二氟乙烯/聚甲基丙烯酸甲酯体系
DOI：
10.1295/polymj.13.273
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
T. Kotaka
中科院分区：
文献类型：
--
作者：
Y. Hirata;T. Kotaka
通过对不同工艺的聚偏氟乙烯（PVF2）和聚甲基丙烯酸甲酯（PMMA）共混物进行热力学分析和动态力学分析，阐明Paul先前报道的低临界溶液温度（LCST）行为对该体系形貌和性能的影响。在PVF2含量φw<0.6的共混物中，两组分可混相。这种共混物在Tg处表现出单玻璃化转变，遵循Gordon-Taylor方案。另一方面，φw>0.6的共混物在200℃下经过足够长时间的熔融混合和退火后，表现出两个Tg和两个Tm，表明其形貌为四相。在这种共混物中，lst型相分离在低至200℃的温度下发生，得到φw = 0.6的非晶态混合物和几乎纯净的PVF2熔体。这种熔体的淬火导致四相形貌，包括Tg = 55°C的混合非晶相，从混合物中生长出的不完美晶相，因此具有低Tm，以及类似于Tg = - 40°C和更高Tm的II型晶体的近纯半晶PVF2畴。
Thermal and dynamic mechanical analyses of variously processed blends of poly(vinylidene fluoride) (PVF2) and poly(methyl methacrylate) (PMMA) were carried out to elucidate the effects of lower-critical-solution-temperature (LCST) behavior reported earlier by Paul on the morphologies and properties of this system. The two components are miscible in the blends with PVF2 content φw<0.6. Such blends exhibit single glass transition at Tg’s, which follow the Gordon-Taylor scheme. On the other hand, the blends with φw>0.6, prepared by melt-mixing and annealing at 200°C for a sufficiently long period of time, exhibit two Tg’s and two Tm’s, implying a four-phase morphology. In such blends an LCST-type phase separation has taken place at a temperature as low as 200°C to give an amorphous mixture with φw≅0.6 and a nearly pure PVF2 melt. Quenching of such melts leads to a four-phase morphology composed of a mixed amorphous phase with Tg≅55°C, an imperfect crystalline phase grown out from the mixture and hence having a low Tm, and a nearly pure semicrystalline PVF2 domains similar to form II crystals with Tg≅−40°C and a higher Tm.