Yousef Jahani | Iran Polymer Inistitute (original) (raw)

Papers by Yousef Jahani

هعلاطم نيا رد يشنكاو حلاصا تيزوپماك ياه نليپورپ ـ كلات زا هدافتسا اب يسكوپا يردوپ ششوپ تاعياض ـ ي... more هعلاطم نيا رد يشنكاو حلاصا تيزوپماك ياه نليپورپ ـ كلات زا هدافتسا اب يسكوپا يردوپ ششوپ تاعياض ـ يلپ رد رتسا ود ردورتسـكا كـي ماجنا هچيپرام و يكيناكم صاوخ و تخير تسا هتفرگ رارق يسررب دروم اهنآ يسانش . هعلاطم تخير يم ناشن يسانش يردوـپ تاعياض هك دهد يلپ رتسب رد كلات تارذ شخپ دوبهب بجوم تهج رد ليهست بجوم و هدش نليپورپ بلاق نايرج تهج رد كلات تارذ يريگ يـم يريگ دوـش . يسكوپا زا يراع هنومن ـ يلپ نامز شيازفا اب رتسا يگدوسرف يسكوپا ندوزفا اب هك دراد يديدش صاوخ شهاك ـ يلپ رتسا عياض رد دوجوم تا يردوپ ششوپ يـلپ هـنومن رد و هداد ناشـن تفا يرتمك رايسب نازيم هب صاوخ نيا يواـح نليپورـپ 20 % ندوزـفا اـب كـلات 20 % ،تاعياـض ًابيرقت تيزوپماك تسا هدش مواقم يترارح يگدوسرف لباقم رد . تـيزوپماك رد يكيناكم صاوخ تمواقم دوبهب يگدوـسرف تارـثا رـبارب رد اـه يم سچ زا يشان دناوت نيزر يگدنب يلپ ياه سم نيا هك دشاب كلات يور رب تاعياض رد دوجوم يسكوپا و رتسا أ يصلاخان دوجو هب هجوت اب هل ياه هدننكرپ رد يزلف يم اهرميلپ يترارح يگدوسرف عيرست بجوم هك يندعم ياه تسا هيجوت لباق ،دوش . نيزر تخپ يسـكوپا ياه ـ يـلپ رتـسا بجوم ي...

International Polymer Processing, 2019

Abstract The present work was focused on studying the effects of different CB loadings on the rhe... more Abstract The present work was focused on studying the effects of different CB loadings on the rheological, thermal, tensile, dynamic mechanical and electrical properties of polyvinylidenefluoride (PVDF) and FKM composites. To these ends, the CB grade and method chosen for compound preparation were CB (N330) and melt mixing, respectively. The composites were melt blended with CB at 190 °C in an internal mixer, after which the properties of filled and unfilled composites were compared. The presence of CB improved the mechanical properties, such as the Young's modulus and tensile strength, and increased thermal stability given the high thermal stability of CB and the interaction between the CB particles and the polymer matrices. The dynamic mechanical thermal analysis (DMTA) showed the glass transition temperatures of the composites. The analysis also revealed that the area under the loss tangent (tan δ) peak decreased and that the tan δ temperature of the rubber phase increased with CB loading. The increase in the electrical conductivity of the composites under different CB loadings was also examined, and the percolation threshold of conductive thermoplastic vulcanizate composite based on conductive CB was observed. The effect of CB and its content on rheological behavior of the PVDF/FKM blends was studied and the experimental data was correlated by a physical model named General Equation Model (GEM). A relation between rheology and conductivity of the blends with filler percolation was found.

Journal of Vinyl and Additive Technology, 2014

ABSTRACT In this study, the influence of the viscosity ratio on the rheology, morphology, and int... more ABSTRACT In this study, the influence of the viscosity ratio on the rheology, morphology, and interfacial interaction of polypropylene and polybutene-1 (PB-1) resins with various melt flow behaviors in the blend are investigated. A droplet-matrix morphology is observed in the scanning electron microscope images for all formulations and the size of particles increased proportionally by increasing the viscosity ratio. Viscoelastic parameters of blends at various viscosity ratios and compositions are measured by small-amplitude oscillation rheometry in the linear viscoelastic region. The Cole-Cole plots showed a nearly semicircular arc for all compositions. This semicircular arc is observed while the viscosity ratio is lower than 1, and the Cole-Cole plots deviated from the semicircular shape at PB-1 content higher than 10 wt%. It is emphasized that, in addition to compatibility, the semi-circularity of Cole-Cole plots affects the size of the dispersed particles, which is under the influence of the viscosity ratio. It is found that the interfacial tensions of polypropylene and PB-1 are not significantly different when changing the viscosity ratio and coarsening the morphology. The form relaxation times in the blends with lower viscosity ratios are shorter than the form relaxation times of the blends with higher viscosity ratios. J. VINYL ADDIT. TECHNOL., 2014. © 2014 Society of Plastics Engineers

Journal of Vinyl and Additive Technology, 2010

ABSTRACT

Polymer International, 2015

ABSTRACT Ethylene norbornene copolymers are synthesized using rac-ethylene bis(indenyl) zirconium... more ABSTRACT Ethylene norbornene copolymers are synthesized using rac-ethylene bis(indenyl) zirconium dichloride/pentaflourophenol modified methylaluminoxane. First, the effect of using modifier in combination with low ratio of Al/Zr on the catalyst activity and co-monomer incorporation is studied. Results of copolymerization reveal a 20 % co-monomer incorporation improvement and rise of activity by 2-fold in presence of modifier. Rheological measurements show higher molecular weight in copolymers synthesized using modified methylaluminoxane. The alternative and dyad blocks microstructures of Copolymers become possible in case of norbornene content of more than 14 mol%. Second, the effect of co-monomer content on rheological and thermal behavior of synthesized copolymers is investigated. Results of rheological study indicate lower molecular weight in samples containing higher norbornene content. DMTA analysis confirms the influence of different microstructures on glass transition temperature. The crystal structure of copolymers having higher molecular weight is emphasized using WAXS and DSC even at higher incorporation of norbornene.

Polymers for Advanced Technologies, 2009

The effect of filler types of mica and talc on the oscillatory shear rheological properties, mech... more The effect of filler types of mica and talc on the oscillatory shear rheological properties, mechanical performance, and morphology of the chemically coupled polypropylene composites is studied in this work. The Maleic Anhydride grafted Polypropylene (MAPP) was used as an adhesion promoter for coupling mineral particles with the polypropylene matrix. The samples were prepared by a co-rotating, L/D ¼ 40, 25 mm twin screw extruder. The tensile tests carried out on the injection molded samples showed a reinforcing effect of talc up to 20 wt% on the Polypropylene (PP). The tensile strength of PP-mica composites showed a slight decrease at all percentages of mica. The effect of chemical coupling by using MAPP on the tensile strength was more pronounced in increasing the tensile strength for PP-mica than PP-talc composites. The complex viscosity curve of pure PP and the composites, showed a Newtonian plateau (h 0) up to 30 wt% at low frequency terminal zone. By increasing the filler content to 40 and 50 wt%, the complex viscosity at very low shear rates sharply increased and showed yield behavior that can be due to the formation of filler particles networks in the melt. At the optimum amount of coupling agent, a minimum in cross over frequency curve against MAPP content is observed. The optimum amount of coupling agent for PP-talc composites is about 1.5%, and about 3% for PP-mica formulations. The analysis of viscosity behavior at power-law high region, revealed the more shear thinning effect of mica than talc on the PP matrix resin.

Journal of Vinyl and Additive Technology, 2014

ABSTRACT In this work, polymerization of caprolactam (CL) was carried out in the presence of acry... more ABSTRACT In this work, polymerization of caprolactam (CL) was carried out in the presence of acrylonitrile butadiene rubber (NBR) during the reactive melt-mixing process. During shear mixing, NBR particles swelled and dissolved in the molten CL, which led to separation and distribution of rubber particles to nanoscale in the dissolution stage. Then, in an internal mixer, supertough Polyamide 6 was prepared via melt polymerization of CL/NBR mixture, sodium caprolactam as a catalyst, and hexamethylene diisocyanate as an activator. The effects of various concentrations of catalyst and activator on the initiation time of the reaction were determined. Physical and mechanical properties of different formulations prepared via reactive melt blending were determined by tensile and impact measurements, differential scanning calorimetry, Fourier-transform infrared spectroscopy, X-ray scattering techniques, transmission electron microscopy, and dynamic mechanical thermal analysis. Experimental results showed that a recipe with 3% nitrile rubber in a CL/NBR mixture enhances the physical and mechanical properties the best, compared with other formulations. This condition led to the formation of NBR nanospheres during melt polymerization of Polyamide 6 as well. J. VINYL ADDIT. TECHNOL., 2014. © 2014 Society of Plastics Engineers

Radiation Physics and Chemistry, 2013

ABSTRACT In this study, a long-chain branched polypropylene (LCB PP) was prepared by electron bea... more ABSTRACT In this study, a long-chain branched polypropylene (LCB PP) was prepared by electron beam irradiation in the presence of polybutene-1 (PB-1) and a trifunctional monomer, trimethylolpropane trimethacrylate (TMPTMA). The effect of PB-1 on branching is evaluated by measuring the viscoelastic behavior in shear and extensional mode of deformation. Long-chain branched structure showed prominent higher zero-shear viscosity (η0) and storage modulus (G′), longer relaxation time and pronounced strain-hardening behaviors. It is found that 10 wt% of PB-1 resin in PP matrix increase the efficiency of branching process which can be due to the effect of PB-1 resin in facilitating the mobility of macro-radicals generated during irradiation. At higher percentages, due to the high tendency of PB-1 resin to β-scission, the degradation reaction is more pronounced than its mobilizing effect in branching process.

Polymer Engineering & Science, 2007

... Correspondence to: Yousef Jahani; e-mail: y.jahani@ippi.ac.ir or y.jahani@yahoo.com DOI 10.10... more ... Correspondence to: Yousef Jahani; e-mail: y.jahani@ippi.ac.ir or y.jahani@yahoo.com DOI 10.1002/pen.20917 Published online in Wiley InterScience (www.interscience.wiley.com). V VC 2007 Society of Plastics Engineers ... 6. H. Chtourou, B. Riedl, and AA Kadi, J. Reinf. Plast. ...

Polymer Engineering & Science, 2013

ABSTRACT The aim of this work is to study the influence of electron beam irradiation on the struc... more ABSTRACT The aim of this work is to study the influence of electron beam irradiation on the structure of polypropylene (PP)/polybutene-1 (PB-1) blend in the branching process. The blend with 10 wt% of PB-1 and 0.5 wt% trimethylolpropane trimethacrylate monomer is prepared and irradiated at different doses. The rheological properties of the melts in shear and extensional mode were evaluated, and their thermal behavior, crystalline structure, and morphology are studied by differential scanning calorimetry, wide-angle X-ray diffraction, and scanning electron microscopy. The presence of long chain branched structure is approved by higher zero-shear viscosity (η0), longer relaxation time and pronounced strain-hardening behavior in the within the range of dose tested. By increasing the irradiation dose and enhancing chain scission in the backbone and long chain branches, the decline in melting temperature, duplication of melting peak, and the decrease in zero-shear viscosity were observed. The morphological study of the blends before and after irradiation revealed no considerable change in PB-1 droplet size and their distribution in the PP matrix. The emulsion theoretical models could predict well the rheological behavior of all samples and no significant change was observed on the interfacial interaction of PP and PB-1. POLYM. ENG. SCI., 54:1747–1756, 2014. © 2013 Society of Plastics Engineers

Polymer Engineering & Science, 2009

ABSTRACT Reactive mixing of polypropylene (PP) and talc with epoxy-polyester resin was preformed ... more ABSTRACT Reactive mixing of polypropylene (PP) and talc with epoxy-polyester resin was preformed using a corotating twin screw extruder, and the rheology, morphology, crystallization behavior, and mechanical properties of composites were evaluated. The melts of composites mixed with resin exhibited yield stress and the variation of viscosity against frequency can be approximated in two lines with various slopes. The measurement of the suspension viscosity can be used to characterize the microstructural state of dispersion. Empirical formula was used to relate viscosity with particle concentration, and the analysis showed that the maximum volume fraction increases by using small amount of epoxy resin in the formulations. The morphological study of composites by scanning electron microscopy revealed that the use of resin improved the dispersion of talc in PP, which leads to the arrangement of talc platelets in the direction of flow even close to wall of the mold. The differential scanning calorimetry showed that the epoxy resin suppressed the nucleation effect of talc on PP while the degree and rate of crystallization increased. The compatibilization by maleic anhydride-grafted polypropylene showed a noticeable increase in tensile strength of composites reactively mixed with epoxy resin. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Polymer Bulletin, 2009

ABSTRACT Reactive mixing of epoxy resin with polypropylene (PP) and talc were carried out on a co... more ABSTRACT Reactive mixing of epoxy resin with polypropylene (PP) and talc were carried out on a co-rotating twin screw extruder. The prepared samples were injection molded to produce the specimens for the measurements of the shrinkage rate. The microstructure of the composites was studied by scanning electron microscope and correlated to the orientation of filler particles and shrinkage behavior. The nano size epoxy resin particles are obvious in SEM images both in the PP matrix and also adhered on the talc powders. The shrinkage measurement revealed that, using epoxy resin in the formulations, leads to a reduction of 14.3% in the shrinkage rates which is isotropic in both flow and transverse directions. The oven aging test at 100°C showed a significant effect of epoxy resin on increasing the thermal stability of composites. The stabilization effect of epoxy resin was more pronounced at higher epoxy resin content. It is believed that the metallic impurities on the surface of talc powder deactivated by the functional groups of epoxy resin and the degradation reaction rate decreased.

Macromolecular Symposia, 2010

... Email: Yousef Jahani (Y.Jahani@ippi.ac.ir). *Correspondence: Yousef Jahani, COR&D... more ... Email: Yousef Jahani (Y.Jahani@ippi.ac.ir). *Correspondence: Yousef Jahani, COR&D Group, Research & Technology Company, National Petrochemical Company, PO Box 14965/115, Tehran, Iran Tel/fax: +982144580159. Publication History. ...

Journal of Applied Polymer Science, 2010

... 3 Faculty of Engineering, Tehran University, PO Box 14155-6455, Tehran, Iran. Email: Y. Jahan... more ... 3 Faculty of Engineering, Tehran University, PO Box 14155-6455, Tehran, Iran. Email: Y. Jahani (Y.Jahani@ippi.ac.ir). *Correspondence: Y. Jahani, Faculty of Processing, Iran Polymer and Petrochemical Institute, PO Box 14965/115, Tehran, Iran. Publication History. ...

Journal of Applied Polymer Science, 2011

Journal of Applied Polymer Science, 2011

Journal of Applied Polymer Science, 2012

Journal of Applied Polymer Science, 2011

Journal of Applied Polymer Science, 2012

ABSTRACT

هعلاطم نيا رد يشنكاو حلاصا تيزوپماك ياه نليپورپ ـ كلات زا هدافتسا اب يسكوپا يردوپ ششوپ تاعياض ـ ي... more هعلاطم نيا رد يشنكاو حلاصا تيزوپماك ياه نليپورپ ـ كلات زا هدافتسا اب يسكوپا يردوپ ششوپ تاعياض ـ يلپ رد رتسا ود ردورتسـكا كـي ماجنا هچيپرام و يكيناكم صاوخ و تخير تسا هتفرگ رارق يسررب دروم اهنآ يسانش . هعلاطم تخير يم ناشن يسانش يردوـپ تاعياض هك دهد يلپ رتسب رد كلات تارذ شخپ دوبهب بجوم تهج رد ليهست بجوم و هدش نليپورپ بلاق نايرج تهج رد كلات تارذ يريگ يـم يريگ دوـش . يسكوپا زا يراع هنومن ـ يلپ نامز شيازفا اب رتسا يگدوسرف يسكوپا ندوزفا اب هك دراد يديدش صاوخ شهاك ـ يلپ رتسا عياض رد دوجوم تا يردوپ ششوپ يـلپ هـنومن رد و هداد ناشـن تفا يرتمك رايسب نازيم هب صاوخ نيا يواـح نليپورـپ 20 % ندوزـفا اـب كـلات 20 % ،تاعياـض ًابيرقت تيزوپماك تسا هدش مواقم يترارح يگدوسرف لباقم رد . تـيزوپماك رد يكيناكم صاوخ تمواقم دوبهب يگدوـسرف تارـثا رـبارب رد اـه يم سچ زا يشان دناوت نيزر يگدنب يلپ ياه سم نيا هك دشاب كلات يور رب تاعياض رد دوجوم يسكوپا و رتسا أ يصلاخان دوجو هب هجوت اب هل ياه هدننكرپ رد يزلف يم اهرميلپ يترارح يگدوسرف عيرست بجوم هك يندعم ياه تسا هيجوت لباق ،دوش . نيزر تخپ يسـكوپا ياه ـ يـلپ رتـسا بجوم ي...

International Polymer Processing, 2019

Abstract The present work was focused on studying the effects of different CB loadings on the rhe... more Abstract The present work was focused on studying the effects of different CB loadings on the rheological, thermal, tensile, dynamic mechanical and electrical properties of polyvinylidenefluoride (PVDF) and FKM composites. To these ends, the CB grade and method chosen for compound preparation were CB (N330) and melt mixing, respectively. The composites were melt blended with CB at 190 °C in an internal mixer, after which the properties of filled and unfilled composites were compared. The presence of CB improved the mechanical properties, such as the Young's modulus and tensile strength, and increased thermal stability given the high thermal stability of CB and the interaction between the CB particles and the polymer matrices. The dynamic mechanical thermal analysis (DMTA) showed the glass transition temperatures of the composites. The analysis also revealed that the area under the loss tangent (tan δ) peak decreased and that the tan δ temperature of the rubber phase increased with CB loading. The increase in the electrical conductivity of the composites under different CB loadings was also examined, and the percolation threshold of conductive thermoplastic vulcanizate composite based on conductive CB was observed. The effect of CB and its content on rheological behavior of the PVDF/FKM blends was studied and the experimental data was correlated by a physical model named General Equation Model (GEM). A relation between rheology and conductivity of the blends with filler percolation was found.

Journal of Vinyl and Additive Technology, 2014

ABSTRACT In this study, the influence of the viscosity ratio on the rheology, morphology, and int... more ABSTRACT In this study, the influence of the viscosity ratio on the rheology, morphology, and interfacial interaction of polypropylene and polybutene-1 (PB-1) resins with various melt flow behaviors in the blend are investigated. A droplet-matrix morphology is observed in the scanning electron microscope images for all formulations and the size of particles increased proportionally by increasing the viscosity ratio. Viscoelastic parameters of blends at various viscosity ratios and compositions are measured by small-amplitude oscillation rheometry in the linear viscoelastic region. The Cole-Cole plots showed a nearly semicircular arc for all compositions. This semicircular arc is observed while the viscosity ratio is lower than 1, and the Cole-Cole plots deviated from the semicircular shape at PB-1 content higher than 10 wt%. It is emphasized that, in addition to compatibility, the semi-circularity of Cole-Cole plots affects the size of the dispersed particles, which is under the influence of the viscosity ratio. It is found that the interfacial tensions of polypropylene and PB-1 are not significantly different when changing the viscosity ratio and coarsening the morphology. The form relaxation times in the blends with lower viscosity ratios are shorter than the form relaxation times of the blends with higher viscosity ratios. J. VINYL ADDIT. TECHNOL., 2014. © 2014 Society of Plastics Engineers

Journal of Vinyl and Additive Technology, 2010

ABSTRACT

Polymer International, 2015

ABSTRACT Ethylene norbornene copolymers are synthesized using rac-ethylene bis(indenyl) zirconium... more ABSTRACT Ethylene norbornene copolymers are synthesized using rac-ethylene bis(indenyl) zirconium dichloride/pentaflourophenol modified methylaluminoxane. First, the effect of using modifier in combination with low ratio of Al/Zr on the catalyst activity and co-monomer incorporation is studied. Results of copolymerization reveal a 20 % co-monomer incorporation improvement and rise of activity by 2-fold in presence of modifier. Rheological measurements show higher molecular weight in copolymers synthesized using modified methylaluminoxane. The alternative and dyad blocks microstructures of Copolymers become possible in case of norbornene content of more than 14 mol%. Second, the effect of co-monomer content on rheological and thermal behavior of synthesized copolymers is investigated. Results of rheological study indicate lower molecular weight in samples containing higher norbornene content. DMTA analysis confirms the influence of different microstructures on glass transition temperature. The crystal structure of copolymers having higher molecular weight is emphasized using WAXS and DSC even at higher incorporation of norbornene.

Polymers for Advanced Technologies, 2009

The effect of filler types of mica and talc on the oscillatory shear rheological properties, mech... more The effect of filler types of mica and talc on the oscillatory shear rheological properties, mechanical performance, and morphology of the chemically coupled polypropylene composites is studied in this work. The Maleic Anhydride grafted Polypropylene (MAPP) was used as an adhesion promoter for coupling mineral particles with the polypropylene matrix. The samples were prepared by a co-rotating, L/D ¼ 40, 25 mm twin screw extruder. The tensile tests carried out on the injection molded samples showed a reinforcing effect of talc up to 20 wt% on the Polypropylene (PP). The tensile strength of PP-mica composites showed a slight decrease at all percentages of mica. The effect of chemical coupling by using MAPP on the tensile strength was more pronounced in increasing the tensile strength for PP-mica than PP-talc composites. The complex viscosity curve of pure PP and the composites, showed a Newtonian plateau (h 0) up to 30 wt% at low frequency terminal zone. By increasing the filler content to 40 and 50 wt%, the complex viscosity at very low shear rates sharply increased and showed yield behavior that can be due to the formation of filler particles networks in the melt. At the optimum amount of coupling agent, a minimum in cross over frequency curve against MAPP content is observed. The optimum amount of coupling agent for PP-talc composites is about 1.5%, and about 3% for PP-mica formulations. The analysis of viscosity behavior at power-law high region, revealed the more shear thinning effect of mica than talc on the PP matrix resin.

Journal of Vinyl and Additive Technology, 2014

ABSTRACT In this work, polymerization of caprolactam (CL) was carried out in the presence of acry... more ABSTRACT In this work, polymerization of caprolactam (CL) was carried out in the presence of acrylonitrile butadiene rubber (NBR) during the reactive melt-mixing process. During shear mixing, NBR particles swelled and dissolved in the molten CL, which led to separation and distribution of rubber particles to nanoscale in the dissolution stage. Then, in an internal mixer, supertough Polyamide 6 was prepared via melt polymerization of CL/NBR mixture, sodium caprolactam as a catalyst, and hexamethylene diisocyanate as an activator. The effects of various concentrations of catalyst and activator on the initiation time of the reaction were determined. Physical and mechanical properties of different formulations prepared via reactive melt blending were determined by tensile and impact measurements, differential scanning calorimetry, Fourier-transform infrared spectroscopy, X-ray scattering techniques, transmission electron microscopy, and dynamic mechanical thermal analysis. Experimental results showed that a recipe with 3% nitrile rubber in a CL/NBR mixture enhances the physical and mechanical properties the best, compared with other formulations. This condition led to the formation of NBR nanospheres during melt polymerization of Polyamide 6 as well. J. VINYL ADDIT. TECHNOL., 2014. © 2014 Society of Plastics Engineers

Radiation Physics and Chemistry, 2013

ABSTRACT In this study, a long-chain branched polypropylene (LCB PP) was prepared by electron bea... more ABSTRACT In this study, a long-chain branched polypropylene (LCB PP) was prepared by electron beam irradiation in the presence of polybutene-1 (PB-1) and a trifunctional monomer, trimethylolpropane trimethacrylate (TMPTMA). The effect of PB-1 on branching is evaluated by measuring the viscoelastic behavior in shear and extensional mode of deformation. Long-chain branched structure showed prominent higher zero-shear viscosity (η0) and storage modulus (G′), longer relaxation time and pronounced strain-hardening behaviors. It is found that 10 wt% of PB-1 resin in PP matrix increase the efficiency of branching process which can be due to the effect of PB-1 resin in facilitating the mobility of macro-radicals generated during irradiation. At higher percentages, due to the high tendency of PB-1 resin to β-scission, the degradation reaction is more pronounced than its mobilizing effect in branching process.

Polymer Engineering & Science, 2007

... Correspondence to: Yousef Jahani; e-mail: y.jahani@ippi.ac.ir or y.jahani@yahoo.com DOI 10.10... more ... Correspondence to: Yousef Jahani; e-mail: y.jahani@ippi.ac.ir or y.jahani@yahoo.com DOI 10.1002/pen.20917 Published online in Wiley InterScience (www.interscience.wiley.com). V VC 2007 Society of Plastics Engineers ... 6. H. Chtourou, B. Riedl, and AA Kadi, J. Reinf. Plast. ...

Polymer Engineering & Science, 2013

ABSTRACT The aim of this work is to study the influence of electron beam irradiation on the struc... more ABSTRACT The aim of this work is to study the influence of electron beam irradiation on the structure of polypropylene (PP)/polybutene-1 (PB-1) blend in the branching process. The blend with 10 wt% of PB-1 and 0.5 wt% trimethylolpropane trimethacrylate monomer is prepared and irradiated at different doses. The rheological properties of the melts in shear and extensional mode were evaluated, and their thermal behavior, crystalline structure, and morphology are studied by differential scanning calorimetry, wide-angle X-ray diffraction, and scanning electron microscopy. The presence of long chain branched structure is approved by higher zero-shear viscosity (η0), longer relaxation time and pronounced strain-hardening behavior in the within the range of dose tested. By increasing the irradiation dose and enhancing chain scission in the backbone and long chain branches, the decline in melting temperature, duplication of melting peak, and the decrease in zero-shear viscosity were observed. The morphological study of the blends before and after irradiation revealed no considerable change in PB-1 droplet size and their distribution in the PP matrix. The emulsion theoretical models could predict well the rheological behavior of all samples and no significant change was observed on the interfacial interaction of PP and PB-1. POLYM. ENG. SCI., 54:1747–1756, 2014. © 2013 Society of Plastics Engineers

Polymer Engineering & Science, 2009

ABSTRACT Reactive mixing of polypropylene (PP) and talc with epoxy-polyester resin was preformed ... more ABSTRACT Reactive mixing of polypropylene (PP) and talc with epoxy-polyester resin was preformed using a corotating twin screw extruder, and the rheology, morphology, crystallization behavior, and mechanical properties of composites were evaluated. The melts of composites mixed with resin exhibited yield stress and the variation of viscosity against frequency can be approximated in two lines with various slopes. The measurement of the suspension viscosity can be used to characterize the microstructural state of dispersion. Empirical formula was used to relate viscosity with particle concentration, and the analysis showed that the maximum volume fraction increases by using small amount of epoxy resin in the formulations. The morphological study of composites by scanning electron microscopy revealed that the use of resin improved the dispersion of talc in PP, which leads to the arrangement of talc platelets in the direction of flow even close to wall of the mold. The differential scanning calorimetry showed that the epoxy resin suppressed the nucleation effect of talc on PP while the degree and rate of crystallization increased. The compatibilization by maleic anhydride-grafted polypropylene showed a noticeable increase in tensile strength of composites reactively mixed with epoxy resin. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Polymer Bulletin, 2009

ABSTRACT Reactive mixing of epoxy resin with polypropylene (PP) and talc were carried out on a co... more ABSTRACT Reactive mixing of epoxy resin with polypropylene (PP) and talc were carried out on a co-rotating twin screw extruder. The prepared samples were injection molded to produce the specimens for the measurements of the shrinkage rate. The microstructure of the composites was studied by scanning electron microscope and correlated to the orientation of filler particles and shrinkage behavior. The nano size epoxy resin particles are obvious in SEM images both in the PP matrix and also adhered on the talc powders. The shrinkage measurement revealed that, using epoxy resin in the formulations, leads to a reduction of 14.3% in the shrinkage rates which is isotropic in both flow and transverse directions. The oven aging test at 100°C showed a significant effect of epoxy resin on increasing the thermal stability of composites. The stabilization effect of epoxy resin was more pronounced at higher epoxy resin content. It is believed that the metallic impurities on the surface of talc powder deactivated by the functional groups of epoxy resin and the degradation reaction rate decreased.

Macromolecular Symposia, 2010

... Email: Yousef Jahani (Y.Jahani@ippi.ac.ir). *Correspondence: Yousef Jahani, COR&D... more ... Email: Yousef Jahani (Y.Jahani@ippi.ac.ir). *Correspondence: Yousef Jahani, COR&D Group, Research & Technology Company, National Petrochemical Company, PO Box 14965/115, Tehran, Iran Tel/fax: +982144580159. Publication History. ...

Journal of Applied Polymer Science, 2010

... 3 Faculty of Engineering, Tehran University, PO Box 14155-6455, Tehran, Iran. Email: Y. Jahan... more ... 3 Faculty of Engineering, Tehran University, PO Box 14155-6455, Tehran, Iran. Email: Y. Jahani (Y.Jahani@ippi.ac.ir). *Correspondence: Y. Jahani, Faculty of Processing, Iran Polymer and Petrochemical Institute, PO Box 14965/115, Tehran, Iran. Publication History. ...

Journal of Applied Polymer Science, 2011

Journal of Applied Polymer Science, 2011

Journal of Applied Polymer Science, 2012

Journal of Applied Polymer Science, 2011

Journal of Applied Polymer Science, 2012

ABSTRACT