稀溶液黏度法测定聚合物共混物的相容性

背景:将热塑性聚氨酯弹性体与双酚A型聚砜或聚甲基丙烯酸甲酯共混可改善热塑性聚氨酯弹性体、双酚A型聚砜、聚甲基丙烯酸甲酯的性能,还可拓宽其应用领域.但共混物的性能主要取决于共混物的相容性.用稀溶液黏度法测定聚合物共混物相容性理论已经很成熟,但关于用稀溶液黏度法测定热塑性聚氨酯弹性体/聚砜和热塑性聚氨酯弹性体/聚甲基丙烯酸甲酯两种聚合物共混体系相容性的研究未见报道.目的:稀溶液黏度法观察热塑性聚氨酯弹性体/聚砜和热塑性聚氨酯弹性体/聚甲基丙烯酸甲酯2种聚合物共混体系的相容性,验证μ和α两类判据在判断聚合物共混体系相容性方面的一致性.设计:观察对比分析.单位:河南科技大学化工与制药学院.材料:热塑性聚氨酯弹性体由洛阳市吉明化工有限公司提供;聚砜由大连第一塑料厂提供;聚甲基丙烯酸甲酯由本实验室合成;N,N-二甲基甲酰胺由北京化工厂提供.方法:实验于2006-05在河南科技大学高分子科学与纳米技术重点实验室完成.以N,N-二甲基甲酰胺为溶剂,配置不同浓度的热塑性聚氨酯弹性体/聚砜和热塑性聚氨酯弹性体/聚甲基丙烯酸甲酯两种聚合物共混体系.在(25.00±0.01)℃的恒温槽中进行测定.用内径0.5～0.6 mm的乌氏黏度计分别测热塑性聚氨酯弹性体/聚砜和热塑性聚氨酯弹性体/聚甲基丙烯酸甲酯两种聚合物共混溶液的流动特性,秒表记录时间,由时间得出相对黏度,进一步可得增比黏度.由实验得到的相对黏度、增比黏度及其他数据,可计算出两种聚合物共混体系的μ值和α值.主要观察指标:两种聚合物共混体系在乌氏黏度计中的流出时间.结果:热塑性聚氨酯弹性体/聚砜共混体系,μ﹥0,α﹥0,表明热塑性聚氨酯弹性体/聚砜共混物相容.热塑性聚氨酯弹性体/聚甲基丙烯酸甲酯共混体系,μ< 0,α< 0,表明热塑性聚氨酯弹性体/聚甲基丙烯酸甲酯共混物不相容.结论:μ、α两类判据在判定聚合物共混物相容性方面具有一致性.稀溶液黏度法操作简单,在测定聚合物共混物相容性方面具有一定的实用价值.

Determination of polyblend miscibility by dilute-solution viscometry

BACKGROUND: Polyblends composed of thermoplastic polyurethane elastomer (TPU) and bisphenol A type of polysulfone (PSF) or polymethyl methacrylate (PMMA) can improve the properties of TPU, bisphenol A type of polysulfone or PMMA and can widen the scope of application. The property of polyblends bad or good depends on the miscibility of polyblends. The dilute-solution viscometry (DSV) is a simple and rapid way for determining the miscibility for polyblends. The study on the determination of miscibility for TPU/PSF and TPU/PMMA polyblends by the DSV has not been reported up to now. OBJECTIVE: To differentiate the miscibility of TPU/PSF polyblend and that of TPU/PMMA polyblend, and at the same time to verify the consistency of μ and α criteria in the determination of polyblend miscibility by DSV.DESIGN: Observation and contrast analysis based on the two polyblend systems.SETTING: Chemical Engineering and Pharmaceutics College, Henan University of Science and Technology.MATERIALS: TPU sample was purchased from Luoyang Jiming Chemical Industry Limited Company, China. PSF sample was purchased from the First Plastic Factory of Dalian, China. PMMA sample was synthesized by our laboratory. N, N-dimethylformamide was provided by Beijing Chemical Plant.METHODS:This study was performed at the Key Laboratory of Polymer Science and Nano-technology, Henan University of Science and Technology in May 2006. The different molar ratio of TPU / PSF and TPU / PMMA polyblends were prepared in N, N-dimethylformamide. An ubbelohde dilution viscometer (whose inner diameter was between 0.5 mm and 0.6 mm) was employed for measuring the relative viscosities of the polymer solutions in DMF at (25±0.01) ℃. The second stop-clock was used to record efflux time. From the efflux time, the relative viscosities could be obtained. Then the specific viscosities could be given by the relative viscosities value. From a series of relative viscosities, the specific viscosities and other data of two polyblends, μ values and α values of two polyblends were obtained.MAIN OUTCOME MEASURES: The efflux time of two polyblend solutions in an ubbelohde viscometer.RESULTS: The μ and α values of TPU/PSF polyblend were all above zero, which showed that TPU/PSF polyblend was miscible. But the μ and α values of TPU/PMMA polyblend were all below zero, which showed that TPU/PMMA polyblend was immiscible. CONCLUSION:The μ criterion is consistent with the α criterion in judging for polyblend miscibility. DSV method is simple, and it can be used in the determination of polyblend miscibility.