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9429207 
Meetings & Symposia 
Medical device application of PVC/EVA-CO nanocomposite blends 
Mcconnell, DC; Lew, CY; Mcnally, GM 
2005 
Executive Conference Management Inc. 
English 
It has been Known for some time that the most commonly used PVC plasticizer, di-(2-ethyhexyl) phthalate(DEHP), can leach out of the PVC Compounds exposing body tissues and fluids to the plasticizer.Therefore by the using a highly flexible polymer such as ethylene-vinyl acetate-carbon momoxide terpolymer (EVA-CO) for the manufacture of flexible medical device and packaging, can provide a viable risk-free alternative to DEHP plasticized PVC formulations, with the nano-dispersion of the biocompatible layered-silicate greatly improving the mechanical, thermal, physical, and physico-chemical properties. It is also hoped that the use of nanocomposites will help address issues releted to plasticizer migration and/or finding method of reducing the need for stabiliser.polyvinyl chloride (PVC) Layered-silicate composites or nanocomposites were derived from melt mixing of an unplasticized PVC and EVA-CO with a synthetic fluorohectorite clay, in modified or unmodified from respectively. Mixing was carried out using a custom-configured twin-screw extruder with different clay ratio. The structureand morphology of the nanocomposites were characterized using wide-angle X-ray different (XRD) and high resolution transmission electron microscopy(TEM).Dynamic mechanical behaviour, thermal property and rheological characteristics of the nanocomposites were studied.Results showed that the PVC/EVA-CO nanocomposites contained hybrid clay structures with varying degree of intercalation and exfolition depending on the formulations.The young's modulus and elongation at break of the nanocomposites was considerably higer than the neat polymer blends, by up to ∼ 40% and ∼ 70% while the OTR and COTR werw reduced by the to ∼ 33% and ∼24% respectively. The nanocomposites recorded lower shear viscosity compared to the virgin blends, while the opposite trend was observed for the composites. The incorporation of stabiliser Package has helped to maintain the yellowness index and transparency of the nanocomposites relative to the virgin PVC Blends and in some cases more superior. the work presnted in this Piece of work includes a comprehensive investigation on the effects of melt blending unplasticised PVC With an ethylene-vinyl acetate-carbon monoxide (EVA-CO) resin and fluorohectorite, in order to achieve flexible PVC/polymer blends with the more superior properties. The results showed how the morphology evolved during the intial melt compounding of the blends with more superior properties. The result showed how the morphology evolved during the intial melt compounding of the blends played a crucial role in the subsequent rheological and mechanical performance, which was primarily due to the hierarchal structure of the PVC resin. The analysis also showed how the presence of the carbonyl group (C=O) in the structure of the PVC resin. The analysis also showed how the presence of the carbonyl group (C=O) in the structure of the EVA-CO In the structure of the EVA-CO terpolymer enhances compatibility with the fluorohectorite and enabled the formation of flexible blends with PVC, compared to the blends with EVA-CO. The mechanical performance of some of the EVA-CO blends was shown to be similar to the conventionally Plasticized PVCs. 
Biocompatibility; Biomedical equipment; Blending; C (programming language); Capillary flow; Carbon monoxide; Chlorine compounds; Commerce; Elastic moduli; Ethylene; Functional polymers; High resolution transmission electron microscopy; Morphology; Nanocomposites; Plasticizers; Polymer blends; Polyvinyl acetates; Reinforced plastics; Resins; Silicates; Structural properties; Thermoplastic elastomers; Ethylene vinyl acetates; Fluorohectorite clay; Mechanical performance; Nanocomposite blends; Physicochemical property; Plasticizer migration; Rheological characteristics; Twin screw extruders; Polyvinyl chlorides