PMMA/α-MSAN共混体系的动态力学行为与结构稳定性

DYNAMIC MECHANICAL BEHMIOR AND STRUCTURE STABILITY OF PMMA/α-MSAN BLENDS

研究了均相、相分离聚（甲基丙烯酸甲酯）（PMMA）／聚（α－甲基苯乙烯丙烯腈）（α－MSAN）共混物的动态力学行为结果表明，在130℃退火48h可使PMMA、α－MSAN及其均相共混物达到稳态结构；在200℃退火1h可使PMMA／α－MSAN共混物接近完全相分离.引人注意的是，仅相分离的PMMA／α－MSAN（40／60）呈现两个动态损耗模量（E”）峰，且两峰的分离程度强烈地依赖于在200℃退火的时间、反映出在热环境中共混物结构从非稳态到稳态的转变.

Blends of poly (methyl methacrylate) (PMMA) and poly (α-methylstyrene-co acrylonitrile) (α-MSAN). exhibiting an LCST behavior, were prepared by solution casting using methyl ethyl ketone (MEK) as solvent. The dynamic mechanical behavior of the single-phase and phaseseparated blend samples through thermal treatments were measured. The results revealed that thedynamic mechanical behavior of the blends depend upon not only their compositions but also thermal histories they were exposed to. As for component polymers and the single-phase blends, their equilibrium States could be achieved by anneaIing at 13α℃ for 48 h, but for phase-separated samples, complete phase separation could be achieved by annealing at 200℃ for 1 h. only PMMA/α-MSAN(40/60)blend shows two transition peaks of dynamic loss modulus (E') in the temperature dispersion curves of the viscoelastic functions for the phase-separated blends. Separation of the two peaks are related to annealing time at 200℃, indicating the change of the blends structure from unstable to stabIe states.