Determination of polyblend miscibility by dilute-solution viscometry

Wensheng SONG; Xuejuan LI; Qingcun FU; Hongyong YAN

ABSTRACT

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.