Iran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101The influence of branching efficiency on the rheology and morphology of melt state long chain branched polypropylene/polybutene-1 blends111156310.22063/poj.2018.2181.1112ENAliForoozanFaculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran, I.R. IranTaherehBehboodiFaculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran, I.R. IranYousefJahaniFaculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran, I.R. Iran0000-0001-5553-1915Journal Article20180427In this study, the compatibility of the blends of polypropylene (PP) and polybutene-1(PB-1) homopolymer before and after long chain branching process were studied. The blends were prepared and long-chain branched directly via reactive extrusion process in presence of free radical initiator and trimethylolpropane tri methacrylate (TMPTMA) poly functional monomer. The optimum percentage of TMPTMA and PB-1 resin have determined by measuring the grafting efficiency and by studying the rheological behavior in shear steady state and transient extensional mode and the morphology of samples were investigated by scanning electron microscopy (SEM). Referring to the blends’ morphologies observed in SEM images which were approved by rheological data, it was found an enhanced compatibility in the blend by branching with 1.5wt% for TMPTMA and 10wt% for PB-1 resin. In this composition, the highest grafting efficiency of 37% and branch index of 5.2 achieved. The zero shear viscosity (η<sub>0</sub>) of PP is increased from 4500 Pa.s to 6800 Pa.s after branching process and enhanced more to 2400 Pa.s by using 10 wt% PB-1 resin. The Long-chain branched structure showed prominent higher zero-shear viscosity, longer relaxation time and pronounced strain-hardening behaviors. The branching behavior of samples were quantified by using extensional viscosity data and the branch index of samples were determined.Iran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101Thermal-insulation performance of low density polyethylene (LDPE) foams: Comparison between two radiation thermal conductivity models1321157210.22063/poj.2018.2185.1113ENRezgarHasanzadehDepartment of Mechanical Engineering, Faculty of Engineering, Urmia University, Urmia, Iran0000-0002-1982-438XTaherAzdastDepartment of Mechanical Engineering, Faculty of Engineering, Urmia University, Urmia, IranAliDoniaviDepartment of Mechanical Engineering, Faculty of Engineering, Urmia University, Urmia, IranRichardEungkee LeeDr. Foam, 33 Silker Street, Vaughan L6A4T4, Ontario, CanadaJournal Article20180430The loss of energy especially in industrial and residential buildings is one of the main reasons of increased energy consumption. Improving the thermal insulation properties of materials is a fundamental method for reducing the energy losses. Polymeric foams are introduced as materials with excellent thermal insulation properties for this purpose. In the present study, a deep theoretical investigation is performed on the overall thermal conductivity of low-density polyethylene (LDPE) foams. The thermal conductivity by radiation is predicted using two different methods. The most appropriate model is selected in comparison with experimental results. The results show that the theoretical model has an appropriate agreement with the experimental results. The effects of foam characteristics including foam density, cell size, and cell wall thickness on the overall thermal conductivity are investigated. The results indicate that by decreasing the cell size and increasing the cell wall thickness, the overall thermal conductivity is decreased significantly. Also, there is an optimum foam density in order to achieve the smallest thermal conductivity. The lowest overall thermal conductivity achieved in the studied ranges is 30 mW/mK at foam density of 37.5 kg.m<sup>-3</sup>, cell size of 100 μm, and cell wall thickness of 6 μm.Iran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101Compression, supramolecular organization and free radical polymerization of ethylene gas2341157410.22063/poj.2018.2252.1117ENDragoslavStoiljkovicUniversity of Novi Sad, Faculty of Technology, Novi Sad, SerbiaSlobodanJovanovićUniversity of Belgrade, Faculty of Technology and Metallurgy, Belgrade, SerbiaJournal Article20180709At low pressure, ethylene gas consists of single translating and rotating molecules and behaves as an ideal gas. With decrease of free volume by compression, various rotating supramolecular particles are formed, which require less space for the movement: molecular pairs, bimolecules and oligomolecules. The appearance of a new kind of particles is manifested as a phase transition of the second or third order. An ideal gas consists of single translating and rotating molecules. α phase consists of rotating single molecules and rotating molecular pairs and it exists when the volume V is reduced to VcIran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101Effect of temperature, heating rate and zeolite-based catalysts on the pyrolysis of high impact polystyrene (HIPS) waste to produce fuel-like products4352157710.22063/poj.2018.2189.1114ENZaherTamriDepartment of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IranAliVaziri YazdiDepartment of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IranMehdiNekoomanesh HaghighiDepartment of Polymerization Engineering, Iran Polymer and Petrochemical Institute, Tehran, IranMehrdadSeifali Abbas-AbadiDepartment of Polymerization Engineering, Iran Polymer and Petrochemical Institute, Tehran, IranAmirHeidarinasabDepartment of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IranJournal Article20180504Pyrolysis of high impact polystyrene (HIPS) waste has been investigated under different process parameters, such as temperature, heating rate and types of zeolitic catalysts to produce valuable liquid products. Liquid, gas and coke as products of pyrolysis and aromatic, naphthene, olefin and paraffin as liquid components were obtained and their molecular weight distributions were studied with changing the process parameters in a stirred reactor. Aromatic-rich hydrocarbons within the gasoline range were the main pyrolysis products. Type of zeolitic catalysts, temperature and heating rate had significant effects on the products quality and quantity. Non-isothermal mass losses of high impact polystyrene were measured using a thermo-gravimetric analyzer (TGA) at heating rates of 5, 15, 30, 45 and 90°C min<sup>-1</sup> until the furnace wall temperature reached 600°C. The DTG (differential thermal gravimetric) curves showed that heating rate had no obvious effect on the degradation trends in the studied range, and by increasing heating rate, the activation energies were decreased obviously from 222.5 to183.6 kJ mol<sup>-1</sup>.Iran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101Electron beam irradiation method to change polypropylene application: Rheology and thermomechanical properties5361157910.22063/poj.2018.2257.1118ENFatemehHassanDepartment of Chemical and Polymer Engineering, Faculty of Engineering, Yazd University, 891581–8411, Iran.MehdiEntezamDepartment of Chemical and Polymer Engineering, Faculty of Engineering, Yazd University, 891581–8411, Iran.Journal Article20180713Irradiation of polymers is one of the most effective and economical methods for modifying their properties and for changing their applications. In this study, an extrusion grade polypropylene (PP) was treated by electron beam irradiation to produce a PP suitable for injection molding. Irradiation was carried out at different doses (0-80 kGy) under atmosphere air and at ambient temperature. Melt flow index (MFI) measurements showed PP samples irradiated in the range of 10 to 40 kGy are suitable to use in injection molding. Electron beam irradiation decreased the viscosity and the shear thinning rheological behavior of PP. The differential scanning calorimetry (DSC) analysis revealed that electron beam irradiation increased the crystallinity percentage and temperature of PP, but decreased the melting temperature. Among all treated samples, the PP<sub>20</sub>, irradiated at the dose of 20 kGy, showed the highest impact resistance. It had higher Young’s modulus and tensile strength, but lower elongation-at-break in comparison with untreated PP.Iran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101Embedding neat and carboxylated nanodiamonds into polypropylene membranes to enhance antifouling properties6374158910.22063/poj.2018.2264.1120ENShahabHoseinpourFaculty of Chemical Engineering, Sahand University of Technology, Tabriz, IranMembrane Technology Research Center, Sahand University of Technology, Tabriz, IranYoonesJafarzadehFaculty of Chemical Engineering, Sahand University of Technology, Tabriz, IranMembrane Technology Research Center, Sahand University of Technology, Tabriz, IranRezaYeganiFaculty of Chemical Engineering, Sahand University of Technology, Tabriz, IranMembrane Technology Research Center, Sahand University of Technology, Tabriz, IranSepidehMasoumiMembrane Technology Research Center, Sahand University of Technology, Tabriz, IranJournal Article20180730The aim of the present work is to enhance the antifouling properties of polypropylene (PP) membrane based on hydrophilicity improvement. Different contents of neat and modified nanodiamond (0.25, 0.50, 0.75 and 1.00 wt.%) were embedded into PP membranes. Nanodiamond nanoparticles were carboxylated by heat treatment method and the presence of carboxyl functional groups on the surface of nanoparticles was confirmed by FTIR analysis. Membranes were then characterized by FESEM, contact angle and tensile strength tests. At the same content of nanoparticles, hydrophilicity, pure water flux and tensile strength of PP/ND-COOH membranes were more than those of PP/ND membranes. Membranes embedded with 0.75 wt. % of neat and modified nanoparticles were used in a submerged membrane bioreactor (SMBR) system along with neat PP membrane. The results showed that critical flux values for neat PP, PP/ND and PP/ND-COOH membranes were 7, 18 and 22 L/(m<sup>2</sup>.h), respectively. Analysis of fouling mechanisms revealed that antifouling properties of 0.75 wt. % PP/ND-COOH membrane were higher than those of other two ones so that irreversible fouling ratio decreased from 88.9% for neat PP to 47.8% for PP/ND-COOH membrane.Iran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101Compatibilization of polycarbonate/poly (ethylene terephthalate) blends by addition of their transesterification product7583157610.22063/poj.2018.2271.1121ENMajidHabibollahiDepartment of polymer processing, Iran polymer and petrochemical Institute, Tehran, IranMortezaEhsaniDepartment of polymer processing, Iran polymer and petrochemical Institute, Tehran, IranJalilMorshedianDepartment of polymer processing, Iran polymer and petrochemical Institute, Tehran, IranJournal Article20180802In this study, poly carbonate (PC) and poly (ethylene terephthalate) (PET) were reactive melt-blended under two different conditions to produce PC/PET copolymers. For each condition, samples were taken at specified mixing times representative a specific structure of copolymers and each one employed to physically compatibilize a PC/PET blend with a fixed composition. Reactive blending and copolymer structure are described by solubility analysis results. Continues declining and going through a minimum are two trends of solubility versus mixing time depending on reactive blending condition. Decreasing and increasing patterns of solubility curves were attributed to the formation of copolymers with longer and shorter block lengths, respectively, and the level of solubility was related to the amount of produced copolymers. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) techniques were employed to investigate blend compatibility. The content and structure of copolymers showed favorable correlation of Tg differences of blend components and PET crystallinity. As expected, Tg of blend components approached to each other by the addition of copolymers, and the copolymers with longer block length caused less Tg differences. The melting point and crystallinity of PET were affected by introducing the copolymers too. In addition to the main melting endotherm, melting endotherm peaks of compatibilized blends had a shoulder that its corresponding melting point and crystallinity are related to the copolymer structure so that the longer length of block copolymer or higher its amount leads to the higher melting points. The SEM micrographs showed that, after the addition of the copolymer, smaller PET particles formed and uniformly dispersed in the PC matrix. A strong correlation between the blend morphology and the level of blend compatibility was demonstrated. The more compatibilized PC/PET blend, the better dispersion of PET particles in the PC matrix was obtained. The results of this study could be a basis for designing and production of compatibilizers suitable to achieve a desired level of compatibility in PC and polyester blends, specially in PC/PET blend.Iran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101Synthesis and identification of polystyrene via conventional and controlled radical polymerization methods: Effect of temperature, initiator and transfer agent on molecular weight and reaction rate8594159010.22063/poj.2018.2288.1122ENMojtabaFarrokhiPolymer Reaction Engineering Department, Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box: 14115-114, Tehran, I.R. IranMahdiAbdollahiPolymer Reaction Engineering Department, Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box: 14115-114, Tehran, I.R. Iran0000-0002-1712-2149Journal Article20180827Polystyrene (PSt) has been known as one of the important polymers with a wide range of applications. Ability to synthesize PSt with different but predictable molecular weights for various applications is very important in the laboratories and industries. In this study, using various simple and inexpensive techniques with only free radical mechanism, it was tried to synthesize PSt with different low (< 2×10<sup>4</sup> g mol<sup>-1</sup>) to high (> 10<sup>5</sup> g mol<sup>-1</sup>) molecular weights. PSts with high and moderate molecular weights (2×10<sup>4</sup>-10<sup>5</sup> g mol<sup>-1</sup>) were synthesized using thermal and conventional free radical polymerizations, respectively. Reverse iodine transfer radical polymerization (RITP) was utilized to synthesize PSt with a low and controlled molecular weight. Conversion, molecular weight distribution and PSt structure were analyzed using <sup>1</sup>H-NMR spectroscopy and size exclusion chromatography (SEC), respectively. Moreover, ω-iodo poly(dimethylsiloxane), i.e. PDMS-I, was also used as a macrotransfer agent for ITP of styrene. Diblock copolymer of PDMS-b-PSt was characterized by 1H-NMR and SEC analyses.Iran Polymer and Petrochemical InstitutePolyolefins Journal2322-22126120190101Development of a rheological model for polymeric fluids based on FENE model95106159210.22063/poj.2018.2318.1125ENHosseinEbrahimiPolymer Group, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, IranAhmadRamazani S.A.Polymer Group, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, IranSeyed MohammadDavachiSoft Tissue Engineering Research Center, Central Tehran Branch, Islamic Azad University, Tehran, IranPolymer Group, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran0000-0001-7002-3708Journal Article20181015Rheological models for polymer solutions and melts based on the finitely extensible non-linear elastic (FENE) dumbbell theory are reviewed in this study. The FENE-P model that is a well-known Peterlin approximation of the FENE model, indicates noticeable deviation from original FENE predictions and also experimental results, especially in the transient flow. In addition, both FENE and FENE-P models have some shortcomings from the point of view of theory. To overcome these shortcomings, a new approximation of the FENE spring force has been established. It has been used to develop a modified constitutive rheological model for polymeric fluids. In the procedure of modeling, the effect of non-affine deformation is introduced into the new model. Comparison between the model predictions and experimental data presented in the literature for transient and steady shear flow of polystyrene indicates that this modified model can predict the rheological behavior of polymeric fluids with a great accuracy. The newly developed modified model could predict different slopes that can cover the behavior of most of the polymeric fluids.