Research On Modification Of Recycled Pet And Procission Arts Of Blow Molding Films

With polyester PET production increasing rapidly, more and more PET bottles waste came into the nature.It is a common challenge for researches to find a new way recycling the PET bottles. This paper researchs on modification of recycled polyester (rPET) by adding terpolymer SAG (styrene -acrylonitrile-glycidyl methacrylate) as chain extender. The chain extension of rPET was seccessful by the break-down of linear chain structure during the twin-screw extrusion, and a new resin with branched chain structure was generated with lower degree of crystallinity.To enhance melt strength, glycidyl methacrylate (GMA) grafted high density polyethylene (GMA-g-HDPE) and HDPE/EVA blend were blended with chain extended rPET matrix respectively.Fanilly, chain extended rPET/GMA-g-HDPE blends and chain extended rPET/EVA/HDPE blends were blow molded into films.The film with high strength and transparency was used widely in industrial packaging and motor wire insulation layer. In addition,the thin film had consistent two-way performance,instead of film products.by complicated two-way tensile process.In the chain extension of rPET, SAG compared with many chain extenders as best chain extender was added 3 shares. Designed many processing technology parameters,the extruder barrel and mold temperature were 250?,260?,270?,270? and 265?.The result showed that the chain exended rPET had a increasing melt temperature of 238.74? and a lower melt flow rate of 15.75g/10min contrasting with the pure rPET (38.00g/10min).Relactive viscosity was 0.833dl/g and relactive molecular weight was 33186.In the chain extend reinforcement reaction,many grafting reaction and meilting blengding formulas were designed and the process parameters adjusted repeatedly.Finally we chose DCP as initiator and St as co-monomer.Result under the condition of 150-180?, twin-screw speed (30r/min),showed that grafting ratio was 1.62%. Melt flow rate of chain extended rPET/HDPE-g-GMA blends decreased to 7.38g/10min.In the EVA with HDPE blending, result under condition of 110-170?, twin-screw speed (30r/min) showed that HDPE and EVA reinforcement had good compatibility. Melt flow rate of chain extended rPET/HDPE/EVA blends decreased to 7.38g/10min.Compared with many processing technology formulas, Chain extended rPET/GMA-g-HDPE with proportion 100:10 and Chain extended rPET/EVA/HDPE with proportion 100:3:10 were blow molded films. Processing technology parameters were adjusted repeatedly.Results showed that the tensile strength and tear tensile strength of chain extended rPET/GMA-g-HDPE film were 44.16MPa and 118.96KN/m respectively under the condition of blow-up with 3,pulling speed with 5m/min.The light transmittance was 87%. The tensile strength and tear tensile strength of chain extended rPET/EVA/HDPE film were 36.84MPa and 138.25KN/m respectively under condition of blow-up with 3.5,pulling speed with 6.5m/min. The light transmittance was 85%.