Search for: polyethylenes
Total 219 records
Production of chlorosulfonated rubber from postconsumer polyethylene and evaluation of produced rubber properties, Article Polymer - Plastics Technology and Engineering ; Volume 47, Issue 5 , 2008 , Pages 508-514 ; 03602559 (ISSN) ; Ramazani, S. A. A ; Shahrokhi, M ; Sharif University of Technology
In order to convert the postconsumer polyethylene to a valuable product, chlorosulfonation of virgin and highly degraded polyethylene has been carried out in the solution phase under atmospheric pressure. Produced chlorosulfonated polyethylene samples from virgin and degraded HDPE are compounded and cured at different temperatures and their mechanical properties are determined. The results show that degradation of used polyethylene does not have noticeable negative effects on the final mechanical properties of produced chlorosulfonated rubbers. Therefore, it can be concluded that chlorosulfonation can be considered as an effective new method for polyolefin recycling
Phase morphology of polyblends of amorphous polycarbonate and semi-crystalline polyethylene terephthalate, Article Iranian Polymer Journal (English Edition) ; Volume 11, Issue 3 , 2002 , Pages 151-157+209 ; 10261265 (ISSN) ; Mehrabzadeh, M ; Mohseni, S. S ; Sharif University of Technology
Phase morphology, state of compatibility and various properties of blends of polycarbonate (PC) with bottle-grade and fibre-grade polyethylene terephthalate (BPET and FPET, respectively) were investigated. It was found that these blends have two-phase separated morphology with partial miscibility. Scanning electron micrographs revealed separated domains of PC-rich and PET-rich zones. PC domains appear spherical increasing in size from 2 μm for PC20/FPET80 up to about 5 μm for PC60/FPET40 blend. Further increase in PC content up to 80% caused phase inversion in which FPET appears as finely dispersed domains in continuous PC matrix. Tg of PC-rich phase decreased from 153 deg;C for pure PC down...
Manufacturing and Investigating of Nano carbon/Polyethylene Nanocomposites via In-situ Polymerization, M.Sc. Thesis Sharif University of Technology ; Ramezani Saadatabdi, Ahmad
In this research UHMWPE/CB nanocomposites were prepared via in situ polymerization using Bi-supported Ziegler-Natta catalytic systems. Magnesium etoxide and carbon black were used as supports of catalyst. TiCl4 accompanied by triisobutyl aluminum and diisobutyl phthalate (DIBP) constituted Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were done in slurry phase under the argon atmosphere. Then, structural, thermal and mechanical properties of produced nanocomposites with different CB content were evaluated by SEM, DSC, TGA, DMTA and tensile tests. Scanning Electron Microscopy (SEM) images also certified very good dispersion of CBs throughout PE matrix....
Synthesis of dithiocarbamates by Markovnikov addition reaction in PEG and their application in amidoalkylation of naphthols and indoles, Article Journal of the Brazilian Chemical Society ; Volume 26, Issue 7 , 2015 , Pages 1500-1508 ; 01035053 (ISSN) ; Dadras, A ; Ramezani, M ; Shamiri, E. V ; Hooshmand, S. E ; Hashemi, M. M ; Sharif University of Technology
Sociedade Brasileira de Quimica 2015
Synthesis of dithiocarbamates by the one-pot three-component Markovnikov addition reaction of an amine, carbon disulfide and an alkyl vinyl ether or N-vinylpyrrolidone is reported in polyethylene glycol (PEG) under a mild and green procedure with high yields and completely regiospecific. Also, the products were used as efficient starting materials for amidoalkylation of electron-rich arenes such as naphthols and indoles
Experimental study and mathematical modeling of partitioning of β-amylase and amyloglucosidase in PEG-salt aqueous two-phase systems, Article Journal of Chemical and Engineering Data ; Volume 55, Issue 11 , 2010 , Pages 4968-4975 ; 00219568 (ISSN) ; Vossoughi, M ; Taghikhani, V ; Safekordi, A. A ; Alemzadeh, I ; Sharif University of Technology
In this study, the partitioning of β-amylase in aqueous two-phase systems (ATPS) containing polyethylene glycol (PEG) with a molar mass of 6000 and 10 000 and KH 2PO 4 at T = (301.65 and 304.65) K was experimentally studied. In addition, the partitioning of amyloglucosidase in ATPS containing polyethylene glycol with molar mass of 4000, 6000, and 10 000 in the presence of Na 2SO 4 at T = (301.65 and 305.65) K was investigated. The effects of molar mass of PEG, temperature, mass fractions of salt, and the length of the tie line on partition coefficients of the enzymes were also studied. The experimental results showed that while the partition coefficients of enzymes decrease with increasing...
Radical chlorination of polyethylene and molecular structure characterization of reaction products, Article Polymer Journal ; Volume 37, Issue 9 , 2005 , Pages 661-668 ; 00323896 (ISSN) ; Ramazani S. A., A ; Shahrokhi, M ; Sharif University of Technology
In this research the radical chlorination reaction of polyethylene has been carried out in perchloroethylene solvent under atmospheric pressure, using chlorine gas and UV light. In order to characterize the structural configuration of chlorinated polymer and study the reaction rate, different samples have been taken in equal periods of time during the reaction time. The FT-IR and H NMR spectra of these samples have been recorded and interpreted. The sequences of methylene groups between two subsequent chloromethylene groups in the polymeric chains have been determined through H NMR spectra and the obtained results have been confirmed with the data of some model compounds. The relative...
Co-crystallization in ternary polyethylene blends: tie crystal formation and mechanical properties improvement, Article Polymer International ; Volume 65, Issue 12 , 2016 , Pages 1405-1416 ; 09598103 (ISSN) ; Bagheri, R ; Pircheraghi, G ; Sharif University of Technology
John Wiley and Sons Ltd 2016
Understanding the co-crystallization behavior of ternary polyethylene (PE) blends is a challenging task. Herein, in addition to co-crystallization behavior, the rheological and mechanical properties of melt compounded high density polyethylene (HDPE)/low density polyethylene (LDPE)/Zeigler − Natta linear low density polyethylene (ZN-LLDPE) blends have been studied in detail. The HDPE content of the blends was kept constant at 40 wt% and the LDPE/ZN-LLDPE ratio was varied from 0.5 to 2. Rheological measurements confirmed the melt miscibility of the entire blends. Study of the crystalline structure of the blends using DSC, wide angle X-ray scattering, small angle X-ray scattering and field...
Binary and ternary blends of high-density polyethylene with poly(ethylene terephthalate) and polystyrene based on recycled materials, Article Polymers for Advanced Technologies ; Volume 22, Issue 5 , 2011 , Pages 690-702 ; 10427147 (ISSN) ; Shojaei, A ; Bagheri, R ; Sharif University of Technology
Binary blends of recycled high-density polyethylene (R-HDPE) with poly(ethylene terephthalate) (R-PET) and recycled polystyrene (R-PS), as well as the ternary blends, i.e. R-HDPE/R-PET/R-PS, with varying amounts of the constituents were prepared by twin screw extruder. The mechanical, rheological, thermal, and scanning electron microscopy (SEM) analyses were utilized to characterize the samples. The results revealed that both R-HDPE/R-PET and R-HDPE/R-PS blends show phase inversion but at different compositions. The R-PET was found to have much higher influence on the properties enhancement of the R-HDPE compared to R-PS, but at the phase inverted situation, a significant loss in the tensile...
Long-term mechanical performance of polyethylene pipe materials in presence of carbon black masterbatch with different carriers, Article Polymer Testing ; Volume 91 , 2020 ; Pircheraghi, G ; Sarafpour, A ; Sharif University of Technology
Elsevier Ltd 2020
In this paper, two types of carbon black (CB) masterbatch with different carriers, i.e. HDPE and LDPE, are used to produce black compounds using three PE100 resins with various short chain branching distributions. Due to difference in short chain branch (SCB) distribution, the used polyethylene resins behave differently in microstructure development and long-term creep behavior. The microstructural analysis using different DSC techniques and rheological measurements revealed more sensitivity of the polyethylene resin with uniform comonomer distribution to the carbon black aggregates and their polymeric carriers. The Full Notched Creep Test (FNCT) was performed to determine the long-term...
Thermo-oxidative degradation during sintering of polyethylene particles, Article Journal of Applied Polymer Science ; Volume 138, Issue 19 , 2021 ; 00218995 (ISSN) ; Pircheraghi, G ; Sharif University of Technology
John Wiley and Sons Inc 2021
Polymer sintering is not only a well-established procedure for producing functional polymeric parts, but it is also the basis for the relatively new additive manufacturing technique, selective laser sintering. Although studying the impact of thermo-oxidative degradation during sintering has significant practical importance, few studies have focused on this aspect of the sintering process. In the present work, we have investigated the active thermo-oxidative degradation mechanisms during sintering of high-density polyethylene (HDPE) particles, the conditions that promote them, and their respective impact on the morphological evolution of the polyethylene particles. To perform a comprehensive...
Superior anti-biofouling properties of mPEG-modified polyurethane networks via incorporation of a hydrophobic dangling chain, Article Progress in Organic Coatings ; Volume 158 , September , 2021 ; 03009440 (ISSN) ; Makki, H ; Ghaffarian Anbaran, R ; Vakili, H ; Ghermezcheshme, H ; Zandi, N ; Sharif University of Technology
Elsevier B.V 2021
PEG-modification is a proven method to enhance the hydrophilicity, protein resistance, and anti-biofouling properties of polymer coatings. It is considered as the gold standard interfacial modification technique such that the higher PEG content, the higher hydrophilicity, and lower protein adsorption, i.e., the initial stage of the biofouling process. Nevertheless, increasing the PEG content causes a higher water uptake, which declines the polymer mechanical strength and increases its hydrolytic degradation rate. Thus, an effective strategy to produce a limited-water-absorbing PEG-modified polymer is to force the majority of PEG molecules to migrate towards the interfacial region while the...
Gas permeability measurement in polyethylene and its copolymer films, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Razavi, J ; Mousavi, A ; Sharif University of Technology
In this research, low density polyethylene (LDPE) and poly ethylene-co-vinyl acetate (EVA) were used as polymeric materials. The methods used to produce LDPE and EVA was Film Blowing and ThermalDry Phase Inversion. The amount of permeability, diffusivity and solubility of O2 and CO2 through above polymers were obtained and also the effect of temperature, pressure and film thickness for LDPE was measured. The Barometric method was considered and measurements were based on ASTM standard. To study film cross-section morphology in EVA, Scanning Electron Microscopy (SEM) was applied. From results we considered that the amount of permeability and solubility were decreased by increasing film...
Investigation of high frequency signal propagation characteristics on HV XLPE cables, Article 7th International Power Engineering Conference, IPEC2005, Singapore, 29 November 2005 through 2 December 2005 ; Volume 2005 , 2005 ; 9810544693 (ISBN); 9789810544690 (ISBN) ; Blackburn, T. R ; Phung, B. T ; Vakilian, M ; Naderi, M.S ; Zhang, H ; Sharif University of Technology
The insulation lifetime of power cables is determined by several factors. One of the more important of these is the occurrence of partial discharge (PD) at the dielectric. The ability to detect and locate a PD source is limited by attenuation of the high frequency PD pulses as they propagate through the cable. Therefore it is necessary to understand the high frequency response of such cables. Further, to enable reconstruction of PD signals as emitted a viable high frequency model for simulation is needed. This paper presents results of measurements of PD calibration pulse and high frequency sinusoid propagation in HV XLPE cables. In addition to the tests a cable model was developed using the...
Study of Mechanical Properties of PP/r-PET Composite Reinforced with Flax Fiber, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar ; Bagheri, Reza
Recycling of polymers, with the aim of environmental protection and economical benefits, is important procedure, which is constantly developing. In this study the effect of the incorporation of recycled PET(r-PET) and recycled polypropylene/Flax(r-PP/Flax) to PP at low (20wt %) and medium content (40wt %) of r-PET was investigated. Polymer compounds were prepared by twin screw extruder followed by injection moulding. The effect of r-PP/Flax and r-PET on PP was evaluated using different techniques such as scanning electron microscopy (SEM), differential scanning calorimetery (DSC), rheological behavior, and mechanical properties (tensile modulus, yield strength, and charpy notched impact...
Investigation Properties of Polyethylene/ Carbon Nanotube Nanocomposites Prepared Via in Situ Polymerization, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad
In this research UHMWPE/MWCNT nanocomposites with different concentrations of nanotubes (0.5, 1.5, 2.5, 3.5 wt %) were prepared via in situ polymerization using a novel Bi-supported Ziegler-Natta catalytic systems. Magnesium etoxide and Multi wall carbon nanotubes functionalized by hydroxyl groups were used as supports of catalyst. TiCl4 accompanied by triethylaluminum constituted Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were done in slurry phase under the argon atmosphere. Support of catalyst on MWCNT was investigated using Fourier Transform Infrared Spectroscopy (FTIR). The results confirmed interaction between catalyst and hydroxyl groups on the surface...
Manufacturing and Investigation the Properties of Polyethylene/ Fumed Silica Nanocomposites Via in situ Polymerization, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad
In this research UHMWPE/FUMED SILICA nanocomposites with different concentrations of nano fumed silica (0.5, 1.5, 2.5, 4.5 wt %) were prepared via in situ polymerization using a novel Bi-supported Ziegler-Natta catalytic systems. Magnesium etoxide and Fumed Silica functionalized by hydroxyl groups were used as supports of catalyst. TiCl4 accompanied by triethylaluminum constituted Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were done in slurry phase under the argon atmosphere. Scanning Electron Microscopy (SEM) images also certified very good dispersion of fumed silica throughout PE matrix. Intrinsic viscosity measurements showed high molecular weight for...
Preparation and Investigating of Polyolephine/graphene Oxide Nanocomposites Via In-situ Ziegler-natta Polymerization, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad
The main object of this thesis is preparation and investigation of polyolophine/graphene oxide nanocomposites by using bi-supported Ziegler-Natta catalytic system and in-situ polymerization. Magnesium ethoxide and graphene oxide were used as supports of catalyst. TiCl4 was accompanied by triisobutyl aluminum (tibia) and diisobutyl phthalate (DIBP) as an electron donor constituting Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were taken place in slurry phase under the argon atmosphere. At the beginning of the polymerization experiment, several type of nanocomposites were made under various conditions (such as different Al/Ti molar ratio) to find optimum condition...
Microstructure-property characterization of a friction-stir welded joint between AA5059 aluminum alloy and high density polyethylene, Article Materials Characterization ; Vol. 98, issue , December , 2014 , p. 73-82 ; Haghshenas, M ; Sahraeinejad, S ; Chen, J ; Shalchi, B ; Li, J ; Gerlich, A. P ; Sharif University of Technology
Aluminum alloys and high density polyethylene are utilized in a wide variety of industrial applications. In the present work the feasibility of friction stir butt welding between AA5059 alloy and high density polyethylene sheets is examined. The bonding mechanism, joint strength, and microhardness are considered in this study. Various welding parameters and tool alignment were investigated until sound joints were achieved by positioning approximately 85% of the rotating tool in the aluminum material on the advancing side (1.4 mm offset) at constant spindle speed and traverse speed of 710 rpm and 63 mm/min, respectively. The results indicate that AA5059 aluminum and high density polyethylene...
Parametric study of buried steel and high density polyethylene gas pipelines due to oblique-reverse faulting, Article Canadian Journal of Civil Engineering ; Volume 42, Issue 3 , 2015 , Pages 178-189 ; 03151468 (ISSN) ; Hojat Jalali, H ; Khajeh Ahmad Attari, N ; Kenarangi, H ; Samadian, M ; Sharif University of Technology
National Research Council of Canada 2015
A numerical study is carried out on buried steel and high density polyethylene (HDPE) pipelines subjected to oblique-reverse faulting. The components of the oblique-reverse offset along the horizontal and normal directions in the fault plane are determined using well-known empirical equations. The numerical model is validated using the experimental results and detailed finite element model of a 114.3 mm (4==) steel gas pipe subjected to a reverse fault offset up to 0.6 m along the faulting direction. Different parameters such as the pipe material, the burial depth to the pipe diameter ratio (H/D), the pipe diameter to wall thickness ratio (D/t), and the fault–pipe crossing angle are...
Injectable polyethylene glycol-laponite composite hydrogels as articular cartilage scaffolds with superior mechanical and rheological properties, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 66, Issue 3 , 2017 , Pages 105-114 ; 00914037 (ISSN) ; Tamjid, E ; Simchi, A ; Bonakdar, S ; Stroeve, P ; Sharif University of Technology
Taylor and Francis Inc 2017
In this study, injectable PEG-based hydrogels containing Laponite particles with mechanical and structural properties close to the natural articular cartilage are introduced. The nanocomposites are fabricated by imide ring opening reactions utilizing synthesized copolymers containing PEG blocks and nanoclay through a two-step thermal poly-(amic acid) process. Butane diamine is used as nucleophilic reagent and hydrogels with interconnected pores with sizes in the range of 100–250 µm are prepared. Improved viscoelastic properties compared with the conventional PEG hydrogels are shown. Evaluation of cell viability utilizing human mesenchymal stem cells determines cytocompatibility of the...