The electrospinning ability of PLA/PEG system at the melt state was investigated through the viscoelastic parameters obtained from dynamic shear and extensional rheometers. PLA and PEG were melt‐blended at various composition ratios. Effect of PEG concentration on the PLA thermal behavior was studied by the differential scanning calorimetry (DSC). According to DSC and wide‐angle X‐ray diffraction, the PLA crystallinity increased and the crystalline structure became more completed (α‐crystal form) in the presence of PEG. Viscoelastic parameters such as zero‐shear viscosity and relaxation time as an indication of elasticity were obtained. The results revealed enhanced polymer chain mobility and disentanglement ought to plasticizing effect of PEG. The critical content of PEG about 20–30 wt % at which the solid–liquid phase separation occurred was in good agreement with the viscoelastic properties. Hence, more than 20% PEG the elasticity diminished and the melt strength became zero. The interfacial tension of the PLA and PEG estimated through the rheological and morphological parameters evidenced the good miscibility of PLA/PEG system at the melt electrospinnig temperature. While the high viscose samples (η0 > 1800 Pa/s) PLA and PLA/PEG (95/5) were not spinnable at the spinning temperature of 180 °C, blends containing 10–30% PEG were easily spun. The finest and continuous fiber mats were obtained by electrospinning of PLA/PEG (80/20) blend (df = 4.8 ± 0.8 μm). More than the critical concentration of PEG (Φ > 30%), lacking the elasticity suppressed the melt electro‐spinnability of PLA/PEG. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44120.

The effect of three types of organoclays on the morphology and mechanical properties of lower critical solution temperature-type poly(acrylonitrile-butadiene-styrene)/poly(methyl methacrylate) (ABS/PMMA) blends was investigated. Polymers were melt-compounded with 2 and 4 wt % of clays using a twin-screw extruder. X-ray scattering and transmission electron microscopy revealed that the intercalation of the nanoclay in the hybrid nanocomposite was more affected by the polarity of the organoclay. Although the morphology of the blends varied by PMMA content, scanning electron microscopy showed smaller PMMA domains for the hybrid systems containing clay par-ticles. Although good dispersion of the nanoclay through the ABS matrix and at the blend interface led to enhancement of tensile strength, the increment of the stiffness was more noticeable for nanocomposites including less polar organoclay. Well-dispersed clay platelets increased the glass transition temperature. In addition, nanoscratching analysis illustrated an improvement in scratch resistance of ABS because of the presence of PMMA and organoclay.

Electrospinning of a polymer melt is an ideal technique to produce highly porous nanofibrous or microfibrous scaffolds appropriate for biomedical applications. In recent decades, melt electrospinning has been known as an eco‐friendly procedure as it eliminates the cytotoxic effects of the solvents used in solution electrospinning. In this work, the effects of spinning conditions such as temperature, applied voltage, nozzle to collector distance and collector type as well as polyethylene glycol (PEG) concentration on the diameter of melt electrospun polylactic acid (PLA)/PEG fibers were studied. The thermal stability of PLA/PEG blends was monitored through TGA and rheometry. Morphological investigations were carried out via optical and scanning electron microscopy. Based on the results, blends were almost stable over the temperature range of melt electrospinning (170 − 230 °C) and a short spinning time of 5 min. To obtain non‐woven meshes with uniform fiber morphologies, experimental parameters were optimized using ANOVA. While increasing the temperature, applied voltage and PEG content resulted in thinner fibers, PEG concentration was the most influential factor on the fiber diameter. In addition, a nozzle to collector distance of 10 cm was found to be the most suitable for preparing uniform non‐woven PLA/PEG meshes. At higher PEG concentrations, alterations in the collector distance did not affect the uniformity of fibers, although at lower distances vigorous bending instabilities due to polarity augmentation and viscosity reduction resulted in curly fibrous meshes. Finally, the finest and submicron scale fibers were obtained through melt electrospinning of PLA/PEG (70/30) blend collected on a metallic frame. © 2017 Society of Chemical Industry

Polylactic acid (PLA) was blended with polyethylene glycol (PEG) and spun via a melt-electrospinning system. The effect of PEG content on the PLA melt and the thermal behaviour of the blend was studied using dynamic rheometry and differential scanning calorimetry, respectively. By fitting a rheological model, parameters such as zero-shear viscosity and the relaxation time of polymer chains were obtained. A substantial reduction of zero-shear viscosity and relaxation time by increasing the PEG content from 0 to 30 wt% was observed. Crystallisation peaks shifted to lower temperatures and the crystallinity level increased in PLA/PEG blends against PEG concentration. The results revealed enhanced polymer chain mobility because of the plasticising effect of PEG. Continuous microfibres were obtained by electrospinning of PLA/PEG blends. While neat PLA was not spinnable at the spinning temperature of 200°C, PLA/PEG blends were easily spun and the lowest fibre diameters of 3-6 μm were achieved with 30% PEG loading, at an applied voltage of 70 kV.

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