SYNOPSISA thermotropic liquid crystalline polymer ( LCP) based on wholly aromatic copolyesters based on hydroxynaphthoic and hydroxybenzoic acid was melt-blended with a thermoplastic poly (phenylene oxide) by corotating twin screw extruder. Rheological properties, temperature transitions, dynamic and mechanical properties, and electron microscopy study have been performed. Rheological study indicated significant viscosity reductions with increasing LCP content leading to ease of processing. From the differential scanning calorimeter ( DSC ) and dynamic mechanical thermal analyzer results, these blends showed incompatibility for the whole range of concentrations. Mechanical properties were found to be slightly improved a t low LCP and dramatically improved a t above 50% LCP contents. In addition, impact strength was significantly increased up to two times after adding 10% LCP into the matrix. The morphology of blends was affected by composition. Droplets and stubby fibrils structures caused lower tensile strength, whereas fibrillar structure improved this property.

The kinetics of the activated anionic polymerization of caprolactam to nylon‐6 and its copolymers has been studied. Nylon‐6 block copolymer and nylon‐6 were prepared at various initial reaction temperatures (140°C to 165°C) by anionic polymerization in an adiabatic dewar flask. Different concentrations of poly(ethylene oxide) (PEO) in 4,4′‐diphenyl methane diisocyanate (MDI)‐capped PEO and 1 mole percent MDI, in a caprolactam solution, were used as the activators with the catalyst, the sodium salt of caprolactam. The kinetics of the reaction were analyzed from an adiabatic temperature rise. A new method was applied to determine the rate parameters. The activation energy, Ea, of nylon‐6 and nylon‐6 block copolymers were found to be 22 kcal/mole. The collision frequency factor, Ao, steadily decreased and the autocatalytic constant, Bo, decreased to a constant value of 16 with the introduction of PEO. However, it was found that the order of reaction, n, was almost a constant value at the second order for all experiments.

The crystallization kinetics of nylon‐6 and nylon‐6 block copolymers (NBC's) containing 1–3 mole % poly(ethylene oxide), PEO, were measured under isothermal and linear cooling conditions. The Avrami equation was used to fit the data. The range of the Avrami index n was from 1.5 to 2.2 for the system studied in the temperature range from 400–454 K. Maximum rate of crystallization was observed in the above temperature range. Nylon‐6 block copolymers showed the maximum crystallization rate at a lower temperature than nylon‐6. When the soft segment exceeded 3 mole %, no crystallization was observed. Cooling rate studies showed the same tendency. The crystallization rate behavior of nylon‐6 block copolymers was similar to the pure nylon.