بازيافت پلي پروپيلن مصرفي در بدنه باتري هاي اسيد سربي با استفاده از تركيب پايدار كننده هاي گرمايي و كوپليمراتيلن پروپيلن تازه

چكيده انگليسي :

Recycling of Polypropylene Used in Lead Acid Battery Cases with Combination of Thermal Stabilizers and Virgin Ethylene Polypropylene Copolymer Ali Bakhshi a bakhshi@ce iut ac ir Date of Submission 2011 05 08 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mahmood Masoomi mmasoomi@cc iut ac irAbstractIn this study blend of virgin polypropylene PP and recycled PP used in lead acid battery cases with differentweight ratios 20 40 60 80 100 wt was prepared by a single screw extruder Melt flow index MFI and carbonyl index were selected for evaluation of blends degradation during the extrusion process Moreover another parameter oxidative induction time OIT was considered to determine the thermal resistance of samples The mechanical properties of the blends were studied by tensile and charpy impact test Analysis of x rayfluorescence XRF was used for identifying metal impurities in the recycled PP For stabilizing of compoundsduring the extrusion process combinations of phenolic Primary Antioxidant P AO and phosphite SecondaryAntioxidant S AO thermal stabilizer with a metal deactivator were used In addition the effect of adding differentmetal deactivators on the recycled PP was investigated For determining the optimum composition of stabilizers inthe 40 60 virgin recycled PP blend the Taguchi method design of experiments DOE was used Also the effectof process conditions such as screw speed and extruder temperature profile on the degradation of blends wasstudied The results of measuring the MFI and carbonyl index showed that in the non stabilized blend adding thevirgin PP to the recycled PP not only did not decrease of polymer degradation during the extrusion process but also adding a small amount of recycled PP to the virgin PP caused to polymer degraded rapidly Three metaldeactivators zinc and calcium stearate CaSt and a commercial metal deactivator were used The results showedthat the combinations of CaSt with thermal stabilizers was more effective in reducing of polymer degradation duringthe extrusion process Commercial metal deactivator and zinc stearate did not decrease the PP degradation Bydesign of experiments the optimum combination of stabilizer was obtained as 1 wt P AO 0 2 wt S AO and 0 5wt CaSt Also DOE results showed that the primary antioxidant has the most influence on reducing thedegradation of PP during the extrusion process Measurement of OIT parameter of the samples which stabilized withoptimum combination of stabilizers proved that the thermal resistance of these samples was similar to virgin PP Similarly from a measurement of carbonyl index of these blends it was found that a little degradation washappened in the extrusion process It was found that the increasing of screw speed provided higher shear rate andhence resulted in the more degradation of PP during recycling The results showed that the best screw speed wasabout 100 rpm Investigation of different extruder temperature profiles showed that increasing extruder temperatureprofiles from 200 C caused an increase of polymer degradation during recycle process The results of impact testsshowed that the stabilized 40 60 virgin recycled PP blend with the optimum combination of stabilizers haveimpact strength similar to virgin PP while the impact strength of this sample in the absence of stabilizer is near tothe impact strength of recycled PP Moreover the tensile test results showed that the stabilization of PP blends withoptimum combination of antioxidant had higher yield strength and elongation at break Keywords recycled polypropylene thermal stabilizer metal deactivator MFI XRF design of experiments

بخشي، علي

بازيافت پلي پروپيلن مصرفي در بدنه باتري هاي اسيد سربي با استفاده از تركيب پايدار كننده هاي گرمايي و كوپليمراتيلن پروپيلن تازه

غير فعال كننده فلزي , شاخص جريان مذاب , XRF , طراحي آزمايش ها