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A more efficient route for the synthesis of phosphonated dimethyl isophthalate, disodium salt is shown to provide a significantly higher yield (42%), in contrast to a previously reported yield (15%). This higher yield enabled the synthesis of phosphonated poly(ethylene terephthalate) (PPET) ionomers using conventional melt polycondensation with ethylene glycol and dimethyl terephthalate. The physical...
To determine the processing temperature of a representative thermotropic liquid crystalline polymer (TLCP) in the super-cooled state, small amplitude oscillatory shear (SAOS), the startup of shear flow and differential scanning calorimetry (DSC) measurements were performed. Good agreement on the onset crystallization temperature was obtained from the SAOS and the startup of shear flow. Compared with...
Polycarbonate/carbon nanotube (CNT) nanocomposites were generated using a supercritical carbon dioxide (scCO2) aided melt blending method, yielding nanocomposites with enhanced electrical properties and improved dispersion while maintaining the aspect ratio of the as-received CNTs. Baytubes® C 150 P CNTs were benignly deagglomerated with scCO2 resulting in 5 fold (5X), 10X and 15X decreases in bulk...
The iso-concentration ordering kinetics of poly(styrene-b-butadiene) in a neutral solvent, toluene, at several concentrations along the solvent extraction path at room temperature were studied using dynamic mechanical rheological measurements and SAXS. These experiments are in contrast to more common studies of the ordering kinetics of block copolymers in which phase separation following temperature...
A semi-continuous process using scCO 2 is reported for processing polymer–clay composites with high clay loading (i.e. 10wt %) by reducing the collapse of the exfoliated clays. Two major modifications are involved in the new procedure: exfoliating the nano-clay directly into the hopper filed with pellets followed by processing the composite immediately and sequentially mixing the clay into...
The effects of block length and solution-casting conditions on the final microstructures and properties of disulfonated poly(arylene ether sulfone) multiblock copolymer (BPSH100–BPS0) films for proton exchange membranes were investigated based on the basic principles of microstructure formation of block copolymers. Morphological studies using transmission electron microscopy and small angle X-ray...
In this study, carbon nano-fibers (CNFs) were used to increase the compressive properties of poly(arylene ether sulfone) (PAES) foams. The polymer composite pellets were produced by melt blending the PAES resin with CNFs in a single screw extruder. The pellets were saturated and foamed with water and CO 2 in a one-step batch process method. Dynamic mechanical thermal analysis (DMTA) was used...
The effect of nanoclay concentration on the molecular orientation and drawability of poly(ethylene terephthalate) PET was examined using thermal and vibrational spectroscopic analysis. Although drawability at 83°C in hot air increased by the addition of nanoclay, the maximum draw ratio was independent of nanoclay concentration. The average molecular orientation of the PET chain was found to mimic...
An environmentally benign process, which uses supercritical carbon dioxide (sc-CO 2 ) as a processing aid, is developed in this work to help exfoliate and disperse nanoclay into the polymer matrices. The process relies on rapid expansion of the clay followed by direct injection into the extruder where the mixture is dispersed into the polymer melt. Results from the mechanical properties, rheological...
In continuation of our goal to determine the ability of CO 2 to plasticize acrylonitrile (AN) copolymers and facilitate melt processing at temperatures below the onset of thermal degradation, a systematic study has been performed to determine the influence of AN content on CO 2 absorption and subsequent viscosity reduction. Our previous report focused on the absorption of CO 2...
Acrylonitrile (AN) copolymers (AN content greater than about 85mol%) are traditionally solution processed to avoid a cyclization and crosslinking reaction that takes place at temperatures where melt processing would be feasible. It is well known that carbon dioxide (CO 2 ) reduces the glass transition temperature (T g ) and consequently the viscosity of many glassy and some semi-crystalline...
The effect of maleic anhydride-grafted polypropylene (MAP) on the mechanical properties of three polypropylene/liquid-crystalline polymer (PP/LCP) blends was investigated. Three LCPs were used in the study. One LCP was a poly(ester amide) and the other two LCPs were copolyesters. The tensile properties of the PP/liquid-crystal (LC) poly(ester amide) blend were affected by the addition of MAP to...
In an earlier paper we considered the effect of polypropylene modified with maleic anhydride (MAGPP) on the properties of in situ composites based on polypropylene (PP) and a thermotropic copolyesteramide (Vectra B). In this paper we consider the effect of MAGPP on the properties of in situ composites based on PP and two different thermotropic copolyesters. It was observed that the MAGPP was nearly...
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