Miscibility Studies on a Copolyester of Bisphenol-A with Terephthalic and Isophthalic Acids/Bisphenol-A Polycarbonate Blends Dolunay Sakar, Fatih Cakar, Ozlem Cankurtaran, Ferdane Karaman Department of Chemistry, Yildiz Technical University, Istanbul-Esenler 34220, Turkey Received 14 July 2009; accepted 21 December 2009 DOI 10.1002/app.31993 Published online 2 March 2010 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: The miscibility behavior of the blends of a copolyester of bisphenol-A with terephthalic and iso- phthalic acids (PAr) and a bisphenol-A polycarbonate (PC) was studied in dilute chloroform solutions at 25  C. The intrinsic viscosity and Huggins’ parameter of the binary mixtures were determined from the intercept and slope of the linear straight line between specific viscosity and the overall polymer concentration at the studied compositions. From experimental results of the intrinsic viscosities of the mixtures, some miscibility parameters Db, Db 0 ,(Db) G , D[g], a, and b were obtained by applying the criteria proposed by the research groups Krigbaum and Wall, Catsiff and Hewett, Garcia et al., Sun et al. and Jiang and Han, respec- tively. The miscibility of mixtures was also studied by using differential scanning calorimetry and fourier trans- form infrared spectroscopy. V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 309–314, 2010 Key words: bisphenol- a polycarbonate; Polyarylate; blends; miscibility; viscosity INTRODUCTION Blending of polymers has given a new direction for developing novel materials. The manifestation of the superior properties of polymer blends depends upon the miscibility of its components at the molecular scale. 1 The most commonly used techniques for inves- tigation of polymer–polymer miscibility are thermal analysis, 2,3 electron microscopy, 4,5 and spectroscopy. These techniques are very powerful for such applica- tions, but they are somewhat expensive for most of the researchers. Therefore, other methods on investigation of polymer–polymer miscibility were proposed either using alternative properties or low cost equipment. Among them, viscometry is a very promising tech- nique. Several works on polymer–polymer miscibility via viscometry have been done in recent years. 6–13 The polycarbonates are well known high perform- ance, engineering molding plastics. Bisphenol-A poly- carbonate (PC) is a transparent high performance thermoplastic having good physical properties such as toughness, dimensional stability, good impact strength, high heat and electrical resistance. Because of these attributes, polycarbonate is used in a wide va- riety of common products including digital media (e.g., CDs, DVDs), electrical and electronic equipment, automobiles, sports safety equipment, reusable food and drink containers, and many other products. 14,15 On the other hand, polyarylate (PAr) is a kind of aro- matic polyester of bisphenol-A with terephthalic and isophthalic acids (50/50) that combine clarity, high heat deflection temperature, high impact strength and good electric properties with inherent ultraviolet sta- bility and flame resistance. 16 Attempts can be made to blend these polymers to get composites with a high performance molding plastic with good ultraviolet sta- bility and flame resistance. Chemical structures of PC and PAr were given in Scheme 1. In this study, the miscibility of PAr and PC was evaluated by several techniques such as viscometry, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Viscometric analysis of polymer–polymer miscibility in dilute solution is based on the Huggins’ equation which reflects the relationship between specific viscosity and polymer concentration. DSC is used to investi- gate the miscibility of the polymer blends using the single glass transition criterion in the binary mix- tures. 3 FTIR is used to seek specific interactions between components of the mixture depending on shift of the characteristic peaks. THEORETICAL BACKGROUND For the ternary mixture of polymer 1, polymer 2, and a common solvent, at constant weight ratio of Correspondence to: O. Cankurtaran (kurtaran@yildiz.edu. tr). Contract grant sponsor: Scientific Research Project Coordination Center of Yildiz Technical University, Turkey. Journal of Applied Polymer Science, Vol. 117, 309–314 (2010) V C 2010 Wiley Periodicals, Inc.