Iran Polymer And Petrochemical Institute and Maroon Petrochemical Company | Date: 2011-03-01
Polyolefin production using an improved catalyst system and, in particular, a method for production of a polyolefin is disclosed. One or more monomers are contacted with a catalyst system. The catalyst system includes titanium tetrachloride as a catalyst precursor and magnesium ethylate as a support for the catalyst precursor. The catalyst system also includes a hydrocarbyl aluminum cocatalyst represented by the formula R_(3)Al, where R is an alkyl radical having 1 to 14 carbon atoms, and where the molar ratio of the hydrocarbyl aluminum cocatalyst to the titanium tetrachloride catalyst precursor ranges from 50:1 to 400:1. The catalyst system also includes a halogenated hydrocarbon as a promoter, where the molar ratio of the halogenated hydrocarbon promoter to the titanium tetrachloride catalyst precursor ranges from 0.001:1 to 300:1.
Ghoreishy M.H.R.,Iran Polymer And Petrochemical Institute
Materials and Design | Year: 2012
This paper is devoted to the description of a newly developed methodology for the determination of the parameters of the Prony series in rubber compounds. Four hyperelastic constitutive equations were selected and combined with the Prony equation to describe the hyper-viscoelastic behaviour of a rubber compound. An in-house simple uniaxial tension test was designed and performed on the three rubber strips with the same length and different widths of 1, 2 and 3. cm. The corresponding finite element meshes of these samples were developed using an adaptive meshing technique. The numerical result of the first sample was compared with experimental results of the associated experiment in conjunction with a Nelder-Mead Simplex optimization method to determine the parameters of the Prony equation. These parameters were further used for the simulation of the other two samples to show applicability and repeatability of the developed method. The comparison of the associated force-extension curves with the experimentally measured data of the two samples confirmed the accuracy and reliability of the predicted parameters by this technique. © 2011 Elsevier Ltd.
Jahani Y.,Iran Polymer And Petrochemical Institute
Polymers for Advanced Technologies | Year: 2011
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=40, 25mm twin screw extruder. The tensile tests carried out on the injection molded samples showed a reinforcing effect of talc up to 20wt% 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 (η0) up to 30wt% at low frequency terminal zone. By increasing the filler content to 40 and 50wt%, 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. © 2009 John Wiley & Sons, Ltd.
Salimi A.,Iran Polymer And Petrochemical Institute
International Journal of Adhesion and Adhesives | Year: 2012
The incorporation of oxidized PP wax OPPW additive into polypropylene resulted to the improved surface adhesion. Atomic force microscopy (AFM) was employed to show either the surface topography or the changes in adhesion force measurements between the probe tip and sample surface. The results of surface characterization tests revealed lower surface roughness and higher adhesion force for higher OPPW content in the blends. The lower surface roughness may be attributed to higher melt flow ability of OPPW and hence better mold filling during sample fabrication. The improvement of surface adhesion was in favor for wetting behavior of solid surface using three test liquids of distilled water, diiodomethane and formamide. The thermodynamic work of adhesion W a was calculated from surface free energy components using geometric mean model of OwensWendtRabel and Kaelble (OWRK approach) and also from the theory of van OssGoodChaudhary (VOGC approach). The adhesion force measurements in AFM were also employed to derive the W a using JohnsonKendalRoberts (JKR approximation). The results indicate that the increase in W a was mainly due to polar part in OWRK approach and the acidbase part in VOGC approach. However, the results of work of adhesion in JKR approximation does not in general scale linearly with the respective OPPW content for the sample series, may be due to varying in near-surface modulus. The adhesion promoting effect of OPPW in the blends seems to work mainly via increasing surface acidbase interactions, better surface wettability and to some extent by plastic deformation mechanisms during debonding. © 2011 Elsevier Ltd. All rights reserved.
Teimouri M.B.,Iran Polymer And Petrochemical Institute
Tetrahedron | Year: 2011
The reactions of 3-formylchromones with alkyl isocyanides in dry dichloromethane at room temperature lead to new types of organic fluorophores (1Z)-3-(alkylimino)-1-[(chromone-3-yl)methylene]-1,3-dihydro-9H-furo[3,4-b] chromen-9-one, which exhibited strong blue emission in solution. The reactions involve a [4+1] cycloaddition followed by an activated electrophilic aromatic substitution at the furan ring and dehydration sequence. © 2011 Elsevier Ltd. All rights reserved.
Zeynali M.E.,Iran Polymer And Petrochemical Institute
Journal of Petroleum Science and Engineering | Year: 2012
One of the problems during drilling operation is wellbore instability. Many parameters affect the wellbore stability. Some of these parameters are related to the properties of drilling mud and its interaction with the formation and some of them are related to the mechanical properties of the formation and the magnitude and distribution of the forces around the wellbore. Generally the wellbore instability is calssified as mechanical, physico-chemical or both. This paper is an attempt to investigate the mechanical and physico-chemical aspects of wellbore stability during drilling operations. . © 2011 Elsevier B.V.
Iran Polymer And Petrochemical Institute | Date: 2015-02-02
The synthesis of a nano-composite, composed of hydroxyapatite (HA) nanoparticles dispersed in polyethylene glycol (PEG) applicable for long-term preservation of historical leather and parchment samples. The nano-composite is synthesized through a simple method by a two phase mixing process at ambient temperature. The mechanical behavior analysis of goat historical leather treated with the prepared nano-composite revealed more softness, better mechanical properties and less structural changes in comparison with the untreated sample. Furthermore, thermal analysis results have confirmed that nano-composite treatment causes a softer amorphous structure with higher water content, more structural homogeneity, and the temperature that maximum weight losing occurred is higher than those for the untreated sample.
Iran Polymer And Petrochemical Institute | Date: 2010-10-06
The various embodiments herein provide a polymer wound dresser in which no drug is used and a method of producing the same. According to an embodiment, a wound dressing film comprises a base polymer film and a laminated backing layer on the base polymer film. The base polymer film includes a natural polymer, a biopolymer and an artificial water absorber polymer. The natural polymer is a chitosan having a preset weight percentage. The biopolymer comprises one or more element selected from a group comprising of a gelatin having a preset weight percentage and a collagen having a preset weight percentage or a combination thereof. The artificial water absorber polymer is selected from a group comprising of a hydrophilic material having a preset weight percentage. The wound dressing film is a single film or a double layered film or a three layered film.
Iran Polymer And Petrochemical Institute | Date: 2010-03-14
A method of synthesizing hydroxyapatite nanorods, having high purity, high crystallinity and high aspect ratio is disclosed here. In one embodiment, high crystalline hydroxyapatite nanorods with relatively stoichiometric structure are prepared via hydrothermal method at 200 C. and under moderate acidic conditions. The synthesized hydroxyapatite nanorods have a diameter of 30-95 nm, a length of 850-1400 nm with an average aspect ratio of 24, degree of crystallinity of 73% and stoichiometry ratio of 1.69. Further it discloses the use of HAp in dental adhesive. The dental adhesive comprising synthesized HAp shows improved diametral tensile strength and high microshear bond strength. Energy dispersive X-ray mapping confirmed the uniform distribution of nanorods in the adhesive matrix. The synthesized hydroxyapatite nanorods have high colloidal stability in the dental adhesive solution. The nanorods are well dispersed and protected from aggregation by their high surface charges confirmed by zeta potential measurement.
Iran Polymer And Petrochemical Institute | Date: 2010-03-14
Unsaturated polyesters e.g. poly (ethylene glycol fumarate) (PEGF) were developed as new coating materials for iron oxide nanoparticles. Different strategies were adopted in their synthesis to provide different characteristics including solubility, molecular weight and structure also degrees of unsaturation. After synthesis of the nanoparticles; the material was applied as a coating on them. These materials were applicable without further processing, however, coatings were cured via thermal, redox or photo initiated crosslinking on the nanoparticles to provide rigid shells on the surface of nanoparticles.