پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران مجله علوم و تکنولوژی پلیمر 10163255 22 4 2013 01 22 Improvement in the Performance of Potato Starch Used in the Water-Based Drilling Fluid via Its Chemical Modification by Grafting Copolymerization بهبود کارایی نشاسته سیب زمینی در سیال حفاری پایه آبی از راه اصلاح شیمیایی آن با روش کوپلیمرشدن پیوندی 251 260 634 10.22063/jipst.2013.634 FA مهدی عبدالهی اکبر ورامش علیرضا نصیری Journal Article 2013 01 22 Increasing the thermal stability and resistance to bacterial attack (bioresistance) of the potato starch used in the water-based drilling fluid is the aim of this work. Four types of potato starch grafted with acrylamide and a mixture of each one with acrylic acid, 2-acrylamido-2-methyl-1-propane sulfuric acid and itaconic acid were synthesized by manganese (IV)-induced redox system at the suitable concentrations of initiator and monomer(s). FTIR spectroscopy was used to verify the grafting of monomers onto the starch. The effect of grafted starches on the rheological and fluid loss properties before and after aging of the water-based drilling fluid prepared with fresh water, 4% saline and the South applied method were investigated. The results showed that temperature and aging of fluid enhance the rheological and fluid loss control properties of water-based drilling fluids prepared in the presence of grafted starches. In other words, grafted starches are stable against thermal degradation and can be used in the formulation of water-based drilling fluids for drilling of deep wells. http://jips.ippi.ac.ir/article_634_cbdb8596cef61b4e70f6f92e97a33c9f.pdf

پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران مجله علوم و تکنولوژی پلیمر 10163255 22 4 2009 12 22 Preparation of Polystyrene Nanocomposite by In Situ Atom Transfer Radical Polymerization: Study of Polymerization Kinetics in the Presence of Clay تهیه نانوکامپوزیت پلی‌استیرن به روش پلیمرشدن رادیکالی انتقال اتم درجا: بررسی سینتیک واکنش در مجاورت خاک رس 261 272 700 10.22063/jipst.2009.700 FA حسین روغنی ممقانی محمد نجفی وحید حدادی اصل* مهدی سلامی کلجاهی Journal Article 2013 02 23 Styrene nanocomposites were synthesized by in-situ atom transfer radical polymerization at 110oC. The variations of monomer conversion and the linearity of semilogarithmic kinetic plot, some signs of living polymerization and constant radical concentration in the reaction medium, were revealed by gas chromatography technique (GC). According to the gel permeation chromatography (GPC) results, the number average molecular weight increased linearly against the monomer conversion indicating the living nature of the polymerization. Weight average molecular weight and polydispersity of nanocomposites were also derived from GPC data. In addition, the PDI value was wider for polymers extracted from nanocomposite samples, and still widened as the clay content increased. Moreover, all the samples experienced a fall in PDI value from nearly 2 to almost 1.1 as the reaction progressed. FTIR results are indications of some interactions between clay surface and monomer, which may be attributed to higher rated in polymerization kinetics. XRD displayed no peak in in-situ synthesized nanocomposites indicating an exfoliated structure in the prepared nanocomposites; conversely, a solution blending technique resulted in an intercalated structure. AFM phase images well displayed the dispersion of nanoclay in the polymeric matrix. The delamination of clay platelets in the polymer matrix of in-situ prepared nanocomposite is demonstrated by TEM images; on the other hand, TEM results revealed the intercalated structure of nanocomposites prepared by solution blending technique. http://jips.ippi.ac.ir/article_700_841318dd326d0e401f86edaacc3c7551.pdf

پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران مجله علوم و تکنولوژی پلیمر 10163255 22 4 2009 12 22 An Experimental and Numerical Verification of Different Hyperelastic Material Models for Rubbers under Tension and Compression Loads بررسی عددی و تجربی رفتار مدل‌های ابر کشسان آمیزه‌های لاستیکی زیربارهای کششی و فشاری 273 284 701 10.22063/jipst.2009.701 FA میرحمیدرضا قریشی Journal Article 2013 02 23 Some numerical and experimental investigations are made on the performance of five different hyperelastic constitutive models (second order polynomial, Yeoh, Arruda-Boyce, Ogden and Marlow) in tension and compression modes. First, the results of the tensile and compression tests on a rubber sample were used to determine the parameters of the models by curve fitting methods. Next, by using an algorithm based on adaptive meshing technique and minimizing the Mises Equivalent Stress, the best finite element mesh of the tensile and compression specimens were obtained. These finite element meshes were then employed for the simulation of the tests, and the predicted force-displacements curves were compared by the experimentally measured data. It is found that the Marlow model gives the best result provided that the stress-strain curve of the simple tension experiment is available. http://jips.ippi.ac.ir/article_701_dc0af015c43ea8124f0092606bc8d335.pdf

پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران مجله علوم و تکنولوژی پلیمر 10163255 22 4 2009 12 22 Effect of Fabrication Process Parameters on the Size of Gelatin/Nanohydroxyapatite Microspheres اثر پارامترهای فرایند ساخت روی اندازه ریزگوی های ژلاتین- نانوهیدروکسی آپاتیت 285 294 702 10.22063/jipst.2009.702 FA شاداب باقری خولنجانی حمید میرزاده* محمد عترتی خسروشاهی Journal Article 2013 02 23 Nano-hydroxyapatite/gelatin (nHA/Ge) microspheres are currently used in bone tissue engineering as bone filler. In this study, the effect of fabrication process parameters on the particle size of nano-hydroxyapatite/gelatin microspheres was investigated. The nHA/Ge microspheres were fabricated using water in oil emulsion. In order to design an experimental design, a surface response model with 2 factors including the rate of shaking and water to oil volume ratio in 3 levels was applied. Particle size was evaluated by using an optical microscope. The morphology of microspheres and distribution of nano-particles within the microspheres were studied by using scanning electron microscope and Ca elemental map obtained from energy dispersive X-ray analysis (EDX), respectively. Statistical analysis of the results obtained from particle size measurements revealed that the rate of shaking has stronger influence on the particle size of microspheres. Morphological studies showed that the fabricated microspheres were spherical with smooth surface. Ca elemental map of the microspheres showed that nano-hydroxyapatite particles distributed uniformly within the microspheres. http://jips.ippi.ac.ir/article_702_fb950050c2c0c1cc0e991cb2861b4e99.pdf

پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران مجله علوم و تکنولوژی پلیمر 10163255 22 4 2009 12 22 Poly(vinyl acetate)-Based Block Copolymer/Clay Nanocomposites Prepared by In Situ Atom Transfer Radical Polymerization نانوکامپوزیت‌های کوپلیمر قطعه‌ای بر پایه پلی(وینیل استات) - خاک رس تهیه شده به روش پلیمرشدن رادیکالی انتقال اتم در جا 295 308 703 10.22063/jipst.2009.703 FA محمدعلی سمسارزاده* مهدی عبدالهی Journal Article 2013 02 23 Atom transfer radical polymerization of styrene (St) and methyl methacrylate (MMA) was performed at 90oC in the absence and presence of nanoclay (Cloisite 30B). Trichloromethyl-terminated poly(vinyl acetate) telomer and CuCl/ PMDETA were used as a macroinitiator and catalyst system, respectively. The experimental results showed that the atom transfer radical polymerization of St and MMA in the absence or presence of nanoclay proceeds via a controlled/living mode. It was observed that nanoclay significantly enhances the homopolymerization rate of MMA, which was attributed to the activated conjugated C=C bond of MMA monomer via interaction between the carbonyl group of MMA monomer and the hydroxyl moiety (Al-O-H) of nanoclay as well as the effect of nanoclay on the dynamic equilibrium between the active (macro) radicals and dormant species. Homopolymerization rate of St (a non-coordinative monomer with nanoclay) decreased slightly in the presence of nanoclay. This could be explained by insertion of a portion of macroinitiator into the clay galleries, where no sufficient St monomer exists due to the low compatibility or interaction of St monomer with nanoclay to react with the macroinitiator. The results obtained from XRD, TEM and TGA analyses were fully in agreement with the kinetic data. Structure of the poly(vinyl acetate)-bpolystyrene nanocomposite was found to be a combination of stacking layers and exfoliated structures while poly(vinyl acetate)-b-poly(methyl methacryale) nanocomposite had an exfoliated structure. This difference in the structure of nanocomposites was attributed to the different capability of the monomers (styrene and methyl methacrylate) to react with the hydroxyl moiety (Al-O-H) of nanoclay. http://jips.ippi.ac.ir/article_703_c7ae0c5659e33506341f64189f19818a.pdf

پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران مجله علوم و تکنولوژی پلیمر 10163255 22 4 2009 12 22 Effective Parameters in the Design of a Loop Reactor for Bulk Propylene Polymerization with Z-N Catalyst بررسی پارامترهای مؤثر بر طراحی راکتور حلقوی در پلیمر شدن توده پروپیلن با کاتالیزور زیگلر- ناتا 309 321 704 10.22063/jipst.2009.704 FA حسین عابدینی* محمد شاهرخی مهرسا امامی Journal Article 2013 02 23 The steps taken in designing a loop reactor for bulk propylene polymerization are discussed. The roles played by several parameters like particle growth factor, catalyst activity and solid fraction on reactor volume at different operating conditions are investigated. At first, based on a fixed production capacity and specific rate of catalyst, reactor volume is determined. Next, the length and diameter of loop reactor are determined according to the critical velocity and heat transfer limitations. An optimum reactor diameter is selected such that the sum of investment and operating costs are reduced and reactor dimensions for construction are practically feasible. By widening the difference between coolant and reactor temperatures, the estimated reactor diameter increases and the length of reactor is decreased. On the other hand, when the slurry flow rate increases, there will be a need for higher pump power and increase in the operating cost. http://jips.ippi.ac.ir/article_704_a195fc60831056bdbae5a0ee155ddd99.pdf