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The compatibility of ternary blends of poly(ethylene naphthalate)/poly(pentamethylene terephthalate)/poly(ether imide) (PEN/PPT/PEI) was studied by examining the transesterification of PEN and PPT. ENPT copolymers were formed in situ as compatibilizers between PPT and PEI components in ternary blends. Differential scanning calorimetric (DSC) results for ternary blends showed the immiscibility of PEN/PPT/PEI, but ternary blends of all compositions were phase-homogeneous after heat treatment at 300°C for more than 60 min. Annealing samples at 300°C yielded amorphous blends with a clear, single glass transition temperature ([T.sub.g]), as the final state. Additionally, ENPT copolymer improved the compatibility of ENPT/PPT/PEI blends, yielding a homogeneous phase in the ENPT-rich compositions. The morphology of the ENPT/PPT/PEI blends was altered from heterogeneous to homogeneous by controlling the concentration of PPT in the ENPT copolymers as well as the concentration of the ENPT copolymers. Moreover, a homogeneous phase with a clear [T.sub.g] was observed when the concentration of PPT in the ENPT copolymer fell to 70 wt% in the ENPT/PEI = 50/50 blends. Experimental results indicate how the concentration of PPT in the ENPT copolymer affects miscibility in the ENPT/PEI blends. POLYM. ENG. SCI., 46:337-343, 2006. © 2006 Society of Plastics Engineers, INTRODUCTION Various polymers can be blended to develop novel materials, with a range of favorable characteristics. However, most such blends are thermodynamically immiscible because the components have different solubilities [1, [...]

Mixtures of diglycidyl ether of bisphenol-A (DGEBA) epoxy resin with poly(4-vinyl phenol) (PVPh) of various compositions were examined with a differential scanning calorimeter (DSC), using the curing agent 4,4'-diaminodiphenylsulfone (DDS). The phase morphology of the cured epoxy blends and their curing mechanisms depended on the reactive additive, PVPh. Cured epoxy/PVPh blends exhibited network homogeneity based on a single glass transition temperature ([T.sub.g]) over the whole composition range. Additionally, the morphology of these cured PVPh/epoxy blends exhibited a homogeneous network when observed by optical microscopy. Furthermore, the DDS-cure of the epoxy blends with PVPh exhibited an autocatalytic mechanism. This was similar to the neat epoxy system, but the reaction rate of the epoxy/polymer blends exceeded that of neat epoxy. These results are mainly attributable to the chemical reactions between the epoxy and PVPh, and the regular reactions between DDS and epoxy. POLYM. ENG. SCI., 45:1-10, 2005. [c] 2004 Society of Plastics Engineers, INTRODUCTION Thermosetting epoxies possess various desirable properties, such as high tensile strength and modulus, excellent chemical and solvent resistance, dimensional and thermal stability, good creep resistance, and excellent fatigue characteristics. [...]

This study demonstrates and discusses ternary miscibility in a three-polymer blend system based on balanced binary interactions. A truly miscible ternary blend comprising poly(ζ-caprolactone) (PCL), poly(benzyl methacrylate) (PBzMA), and poly(vinyl methyl ether) (PVME), was discovered and reported. Miscibility with phase homogeneity (excluding the PCL crystalline domain) in a wide composition range has been demonstrated using criteria of thermal transition behavior, cloud point, and microscopy characterization. At ambient temperature, the three-polymer ternary system is completely miscible within the entire composition range (i.e., no immiscibility loop). However, at slightly elevated temperatures above the ambient, phase separation readily occurred in this originally miscible ternary blend. A quite low 'lower critical solution temperature' (LCST) near 75°C was found for the ternary blend, which is much lower than any of those for the binary pairs. Balanced interactions with no offsetting Δχ among the three binary pairs were a key factor leading to a ternary miscible system., INTRODUCTION Truly miscible ternary blends composed of three polymers differing in properties might offer a unique opportunity to develop a new polymer material with flexible combination from three constituents. An [...]