In this study, poly(lactic acid) (PLA) was blended with chemically modified thermoplastic starch (CMPS) in a twin-screw extruder. The characteristic properties of PLA/CMPS blends were investigated by observing the morphology, thermal, and mechanical properties, and biodegradability. Differential scanning calorimetry showed that the PLA/CMPS were thermodynamically immiscible. However, scanning electron microscopy and Fourier transform infrared studies revealed that the interfacial adhesion was improved by the PLA-gstarch copolymers that were formed at the interface through a transesterification reaction between PLA and CMPS. The crystallinity of the PLA component in the blend was increased by the addition of the CMPS and was highly affected by the morphology of the blend. The tensile strength and elongation were found to decrease in a linear trend with increasing CMPS content. The biodegradability of the blends increased with increasing CMPS content, while initial time lag decreased. POLYM. ENG. SCI., 51:826-834, 2011. ª 2011 Society of Plastics Engineers Recently, in our work, chemically modified thermoplastic starch (CMPS) was introduced [27-30].This article aims at reporting on the utilization of CMPS to tailor biobased and biodegradable PLA blends for applications requiring a balance between cost and properties. To meet this objective, we prepared CMPS through the reactive extrusion processing of starch in the

Blends of a poly(ethylene 2,6‐naphthalate) (PEN) and a liquid crystalline copolyester (LCP), poly(benzoate‐naphthoate) were prepared in a twin‐screw extruder. Specimens for thermal properties were investigated by means of an instron capillary rheometer (ICR) and scanning electron microscopy (SEM). The blend viscosity showed a minimum at 10 wt% of LCP and increased with increasing LCP content above 10 wt% of LCP. Above 50% of LCP and at higher shear rate, phase inversion occured and the blend morphology was fibrous and similar to pure LCP. The ultimate fibrillar structure of LCP phase appeared to be closely related to the extrusion temperature. By employing a suitable deformation history, the LCP phase may be elongated and oriented such that a microfibrillar morphology can be retained in the solid state. Thermal properties of the LCP/PEN blends were studied using DSC and a Rheovibron viscoelastomer. These blends were shown to be incompatible in the entire range of the LCP content. For the blends, the Tg and Tm were unchanged. The half time of crystallization for the LCP/PEN blends decreased with increasing LCP content. Therefore, the LCP acted as a nucleating agent for the crystallization of PEN. The dimensional and thermal stability of the blends were increased with increasing LCP content. In studies of dynamic mechanical properties, the storage modulus (E′) was improved with increasing LCP content and synergistic effects were observed at 70 wt% of LCP content. The storage modulus for the LCP/PEN 70/30 blend is twice that of PEN matrix and exceeded pure LCP.

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Poly(vinylidene fluoride) (PVDF), poly(viny1 fluoride) (PVF), and their blends were prepared by solution casting, followed by quenching in ice water after melting to obtain an a-crystalline phase. The films were drawn by solid state extrusion at two different drawing temperatures, 50°C and 110°C. The Crystalline phases were analyzed by DSC and ETIR. In the undrawn films, the content of p-crystalline phase in the blend of PVDF/PVF 88.5/ 1 1.5 was higher than in the PVDF homopolymer, but it was lower than in the PVDF film with a draw ratio higher than 4. The a-crystalline phase in PVDF/PVF blends was mostly transformed into the p-crystalline phase beyond a draw ratio of 4, regardless of the draw temperature and PVF content. The a-crystalline phase of PVDF systematically transformed into the p-crystalline phase with increasing draw ratio. The crystallinity of PVDF/PVF blend films drawn at 110°C was higher than those drawn at 50°C. In the drawn blend films, characteristic IR bands of the a form were shifted to those of the p form and completely changed into those of p form at draw ratio of 4, regardless of the draw temperature and PVF content.