بررسي رابطه ي ميان فاكتور توزيع طول الياف و خواص رئولوژيكي و مكانيكي كامپوزيت پلي پروپيلن/شيشه

چكيده انگليسي :

Investigation of relationship between fibre length distribution factor and rheological and mechanical properties of glass fiber reinforced polypropylene PP Fatemeh Asoodeh f asoodeh@tx iut ac ir Department of Textile Engineering Isfahan University of Technology Isfahan 84156 8311 IranDegree M Sc Language FarsiSupervisor Dr Ali Zadhoush azadhoush@cc iut ac irAbstractShort fiber reinforced thermoplastics are used increasingly as structural materials because theydon t only provide superior mechanical properties but they can also be easily produced byrapid extrusion compounding and injection molding processes Fiber breakage usually occursin short fiber reinforced thermoplastics processing and resulting final products have FiberLength Distribution FLD The fiber length is governed by a number of factors includingfiber content and processing conditions The mechanical properties of short fiber reinforcedthermoplastics such as strength elastic modulus and fracture toughness are criticallydependent on the fiber length distribution In this project parameters governing fiber length distribution rheological properties andmechanical properties of the injection moulded specimens were investigated This researchwork has been divided in three sections 1 Fiber distribution length and average length were determined 2 Rheological properties of the composite material for several length distribution and fibercontent were measured 3 Mechanical properties of injection moulded specimens were determined The obtained results indicate that The investigated samples are visco plastic fluids The Herschel Bulkley model that has threevaribles 0 k n is the best model for describing samples behaviour Although change infiber length distribution doesn t change the rheological model that define the fluid behaviour but it changes the parameters values of this model Consistency index k and yield stress 0 are directly related to fiber length distribution factor while Non Newtonian index n showsthe inverse relationship with fiber length distribution factor In all specimens stress and melt viscosity increase for higher fiber volume fraction Furthermore by decrease of fiber length distribution factor viscosity and stress aresignificantly decreased It should be noted that in the composite rheological behaviour fiberlength is a more effective parameter than fiber volume fraction The results of tensile and bending tests shows a direct relationship between fiber lengthdistribution factor and composite strength and modulus For mechanical properties ofcomposite fiber volume fraction is more effective parameter than fiber length distributionfactor On the other hand bending modulus and strength are higher than their tensile valuesand have a greater range of changes with less influence by fiber length distribution factor Key words Short Fiber Composits Fiber length distribution factor Rheology

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بررسي رابطه ي ميان فاكتور توزيع طول الياف و خواص رئولوژيكي و مكانيكي كامپوزيت پلي پروپيلن/شيشه

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