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Studies On Processability Improvement Of Ultrahigh Molecular Weight Polyethylene And Influence On Its Structure And Properties

Posted on:2007-09-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:M J XieFull Text:PDF
GTID:1101360185494664Subject:Materials science
Abstract/Summary:PDF Full Text Request
Ultrahigh molecular weight polyethylene (UHMWPE) could be used in many fields because of its outstanding properties such as excellent toughness, high abrasion resistance, low friction, good chemical resistance and biocompatibility. However its poor processability limits its application. The melting fluidity of UHMWPE must be enhanced in order to mold it with conventional thermoplastic processing equipment .In this work, polyethylene glycol (PEG), PEG/diatomite hybrid (PPA1), PEG/glass bead hybrid (PPA2) were used as processing aids to improve the rheological properties of UHMWPE/PP blend respectively. The influence of PEG and PEG-containing additives on the processabiliy, mechanical properties, and tribological properties of UHMWPE/PP blend were investigated. The mechanisms of viscosity reduction caused by incorporating PEG and PEG-containing additives were also explored. In addition, the study on processing of UHMWPE/PP blends by injection molding was another part of this work. The main results and conclusions are listed as follows.The addition of small amount of PEG and PEG-containing additives can effectively improve the processability of UHMWPE/PP blend, resulting in significant reduction of die pressure and melt viscosity, obviously increasing of the flow rate at a given die pressure, and improvement of extrudate appearance. The mechanical properties of the blend are hardly impaired, the tribological properties under some condition could be enhanced.The viscosity reduction effect of UHMWPE/PP blend caused by PEG incorporation is related with PEG molecular weight, PEG molecular weight...
Keywords/Search Tags:ultrahigh molecular weight polyethylene, polypropylene, polyethylene glycol, hybrid processing aid, rheological properties, disentanglement, mechanical properties, tribological properties, injection molding, skin-core structure, oxidative degradation
PDF Full Text Request
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