پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Prediction of Optimum Time for Oxygen Clearance in Solution
Polymerization of Vinyl Acetate in Isopropyl Alcohol
تعیین زمان بهینه اکسیژن زدایی طی پلیمرشدن در محلول وینیل استات در حلال ایزوپروپیل الکل
101
108
731
10.22063/jipst.2007.731
FA
محمدعلی
سمسارزاده
محمدرضا
کلایی
Journal Article
2013
02
24
As we know oxygen is one of the main inhibitors of polymerization of vinyl acetate. Therefore, nitrogen is used in order to make sure of system's high purity. To maintain purity it is necessary to find out the rate of the oxygen<br />solution in polymerization system under different conditions of polymerization. It is concluded that incoming nitrogen to the system would remove the oxygen from the system and on the other hand the increase in temperature<br />is a great help. The time length for this process is evaluated in polymerization system at the same time.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Study of the Effect of Heat Treatment on Nylon 66 Tire Cords Structure and its Physical Properties
بررسی اثر عمل آوری گرمایی بر ساختار و خواص فیزیکی رشته های تایر نایلون ۶۶
109
117
790
10.22063/jipst.2007.790
FA
صغری
رمضانی
محمد
مرشد
محمد
قانع
Journal Article
2013
03
03
In this research, the effect of temperature on the physical and chemical behavior of nylon 66 tire cords in the range of 50-200°C and 16 h testing was studied. The results showed that heat treatment considerably reduced the breaking strength of cords. The intensity of reduction of breaking strength below 100°C and above 120°C was more pronounced than intermediate temperatures. The changes in properties above 120°C were attributed to broadening of molecular weight distribution as ascertained by GPC studies. The increase of irregularity in the polymeric chains was ascertained by shrinkage and birefringence studies. It is found that by raising the temperature, both chain folding and thermal degradation occur, because there is decomposition of the amorphous region occurring as evident by FTIR spectroscopy and elastic modulus and birefringence studies. The changes in properties below 100°C were attributed mainly to decomposition of the amorphous region. On the other hand the percentage of crystallinity increased and tire cord became more brittle and its tensile strength below 100°C was decreased. The lower reduction of tensile properties in the intermediate temperatures of 100-120°C was due to no change in polydispersity and irregularity of the polymeric chains compared to higher temperatures as well as smaller increase in percentage of crystallinity compared to lower temperature treatments.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Uncrosslinked Polyethylene Foam Production with Chemical Blowing Agents
تولید اسفنج پلیاتیلن شبکهای نشده با استفاده از عوامل پفزای شیمیایی
119
124
791
10.22063/jipst.2007.791
FA
فرامرز
افشار طارمی
علی
حسین لو
Journal Article
2013
03
03
In many processes polymeric foams can be produced by using chemical or physical blowing agents. In this work for polyethylene foam production, the chemical blowing agents and compression moulding process were employed. At first, by using DSC diagram of two polyethylene grades, a suitable polyethylene grade was selected for foam production and then we discuss about blowing agent critical percent in foam production.<br />Usually it was assumed that foam density decreases by increasing the chemical blowing agent concentration, but it is discovered in this work that there is a critical percent for each chemical blowing agent, for beyond critical percentage foam density increases by increasing blowing agent percent. The level of critical quantity is related to the amount of released gas of each chemical blowing agent. In this study, we have used three types of chemical blowing agents. Because of relationship between foam properties and foam density, a formulation is presented which is applicable for a special end use.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Study on Shape Memory of Poly(vinyl chloride)/Thermoplastic Polyester Urethane Blends
مطالعة حافظة شکلی در آمیخته های پلی(وینیل کلرید)/پلیاستر یورتان گرمانرم
125
132
792
10.22063/jipst.2007.792
FA
بهاره
رشیدی
نادره
گلشن ابراهیمی
Journal Article
2013
03
03
In this research, shape memory effect of polycaprolactone based polyurethane/poly(vinyl chloride) blends in which the PVC weight percentage are 10, 20, 30, 40, 60 and 80 were studied using DMA apparatus. The compatibility, tension and dynamic-mechanical properties of these blends have been studied by the authors and this paper specifically deals with the tests results of shape memory effect. The results of tension tests in about 20 percent showed that with increasing PVC content in the blends, recovery rate of temporary shape to permanent shape, the degree of recovery, and the fixity in quantity of temporary shape are improved. Therefore, the supplementary shape memory tests were performed on the blend with the highest PVC weight percent (80 percent). In this blend, with increasing tension in thermomechanical cycle, the amount of recovery to earlier shape is decreased due to higher plastic strain. The shape memory tests in consecutive cycles were done on this blend and the behavior of the first cycle was compared with the second and the third cycles. One small tensile handy apparatus was used in order to accomplish shape memory tests in higher tension values and the DMA results were registered. In this research the blend with 80 weight percent of PVC as the best shape memory effect was selected.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Comparison of Compatibilizer Effect on Blend Fibers Including Virgin and Recycled PET
مقایسه اثر سازگارکننده بر خواص الیاف آمیخته PET خالص وبازیافتی
133
145
793
10.22063/jipst.2007.793
FA
شیرین
شفایی
نادره
گلشن ابراهیمی
Journal Article
2013
03
03
PP/PEP blends, because of different solubility factors, are incompatible. The aim of this research was to use PP-g-MA compatibilizer in a two-component blend. After preparing this compatibilizer in internal mixer and investigating different parameters on producing process, optimum compatibilization was obtained. PP/PET (60/40) Blend fibers with different percentages of this compatibilizer in two groups, including recycled and virgin PET were prepared. The results show that PP-g-MA causes smaller PET phase in fibers including virgin PET but in fibers with recycled PET, up to 5 wt% of compatibilizer, the cross-section uniformity is reduced. In addition, by increasing compatibilizer, the mechanical properties of two groups including recycled and virgin PET, at first increase and then decrease. Cold drawing causes increase in crystallinity and therefore enhancement of tensile strength. It is obvious that fibers with recycled PET and compatibilized fibers demonstrate better mechanical properties by cold drawing.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Study of Catalyst, Aging Time and Surfactant Effects on Silica Inorganic Polymer Characteristics
مطالعه اثر کاتالیزور، زمان رشد و ماده فعال در سطح روی مشخصات پلیمر معدنی سیلیکا
147
153
794
10.22063/jipst.2007.794
FA
مجید
پاکیزه
محمدرضا
امیدخواه
رامین
کریم زاده
عبدالصمد
زرین قلم
Journal Article
2013
03
03
In the present study the sol-gel method is used for synthesis of amorphous nanostructure silica polymer using tetraethoxysilane (TEOS) as silicon source. This polymer can be used in manufacturing of nanoporous asymmetric<br />membranes. The effect of catalyst on silica particle size has been studied under acidic and basic conditions.زAcid-catalyzed reaction leads to the formation of fine particles while the base-catalyzed reaction produces<br />larger particles. The presence of cationic template surfactant namely cetyl pyridinium bromide (CPB)زdirects the structural formation of the polymer by preventing the highly branched polymeric clusters. This will increase the effective area of the produced silica membrane. Nitrogen physisorption tests by Brunaver- Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods revealed that the surface area of the membrane increases significantly around 5-folds when acid-catalyzed reaction is used. 29Si-NMR test is also used to study the aging time effect on the level of silica polymer branching. The results show that in acidic condition, aging time up to three weeks can still affect branching. The calcinations process in which the organic materials and CPB (surfactant) are burned and released from the silica particles, is studied on template free silica materials as well as templated silica materials using TGA and DTA techniques.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Study of Low Pressure Cold Plasma on Moisture Properties of Polyester Fabric
بررسی اثر پلاسمای سرد و کم فشار بر خواص رطوبتی پارچه پلی استر
155
163
795
10.22063/jipst.2007.795
FA
الهه
مسایلی
صدیقه
برهانی
Journal Article
2013
03
03
Low temperature plasma technology is well established in surface modification of polymer materials on industrial scale. This method modifies surface properties of polymers without chemicals, manual work and reducing chemicals and energy consumption. In this study, low pressure plasma treatment was used to develop hydrophilic properties of polyethylene terephthalate (PET) fabrics. It was found that, plasma treatment had a significant effect on the hydrophilicity properties of PET fibers. Plasma treatment increases wetting, wicking and electric conduction of fibers but the recovery of fibers was not affected by the plasma treatment. Also, scanning electron microscopy (SEM) micrograph show some surface fibers etching that created some voids.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Sorption Behavior of CO2 and CH4 of Glassy Polymeric Membranes and Analytical Discussion of Partial Immobilization Model
رفتار جذبی CO۲ و CH۴ درغشاهای پلیمری شیشهای و توصیف تحلیلی مدل عدم تحرک جزئی
165
178
796
10.22063/jipst.2007.796
FA
مجید
مهدویان
سید علیاصغر
قریشی
Journal Article
2013
03
03
Among various reported membrane-based gas separation processes, the best explanation is generally achieved by the solution-diffusion model. The main factors in this model are the solubility and diffusivity of permeationcomponents through the membrane. The prediction of permeability and diffusivity in multicomponent gas permeation as well as the separation evaluation equilibrium and kinetic interactions requires a proper explanation of sorption and diffusion phenomena in the polymer matrix. Investigation made by various researchers in this area shows that the equilibrium interaction (sorption step) plays the key role in determining diffusion and permeation in multicomponent system. Therefore, the proper description of sorption behaviour of gas mixture in the polymer is an essential task. The dual-mode sorption (Langmuir-Henry) is usually used for the description of equilibrium isotherm of gases in glassy polymers based on this model; the diffusive behaviour of the system is subsequently analyzed by the partial immobilization model. In this study, the equilibrium sorption of CO2/CH4 mixture in various polymers was modelled using the experimental data available in the literature. The differences in the mechanism of adsorption for CO2 and CH4 were analyzed by considering variations in mode of sorption for each adsorbed component at different pressures. By introducing a new adsorption parameter, P50/50, (the pressure at which the portion of two modes in sorption are equal the contribution of each adsorbed component in occupying Langmuir sites was evaluated. The results indicate that the relative significance of sorption mode for each component is a function of pressure and it is different for various polymers.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Synthesis and Characterization of Diaminodisulfide Derivatives and
their use as Accelerator in Curing Process of Rubber Compounds
سنتز و شناسایی مشتقات دی آمینو دی سولفیدی و به کارگیری آنها به عنوان شتاب دهنده در فرایند پخت آمیزه های لاستیکی
179
186
797
10.22063/jipst.2007.797
FA
سعید
تقوایی گنجعلی
ارسلان
بیگ زاده
کاظم
سبحانمنش
فرسا
فتوحی
نصراله
مجیدیان
Journal Article
2013
03
03
In some special cases, rubber compounds with high amounts of unsaturated elastomer are recommended with organic sulfur donors instead of mineral sulfurs. In this condition, activated sulfur is produced in situ and curing<br />process is facilitated without accelerators. Organic sulfur donor compounds have low thermal stability and in the vulcanization temperature produce free and activated sulfurs. The advantages of these compounds are:<br />1. High effectiveness of curing agent in low quantities in rubber compounds manufacturing.<br />2. Producing activated sulfurs in controlled condition and avoiding the over curing of rubber compounds.<br />In this report the novel synthesis of some derivatives of diamino-disulfides which can be applied as sulfur donors in vulcanization of special rubber compounds is introduced. The key process is reaction of sulfur<br />monochloride with amines in petroleum ether as solvent in low temperature. Dithio-dimorpholine(DTDM), dithio-dipipyridyl (DTDP), dithio-bis dibutylamine (DTBDB) and dithio-bisdiisopropyl amine (DTBDI) were prepared according to this method. All products thus obtained were characterized by 1H and 13C-NMR spectroscopies. The effects of accelerating and sulfur donoring of all prepared agents were detected in rubber compounds with natural and synthetic rubber bases. All physical, chemical, reological and mechanical properties of rubber compounds based on prepared sulfur donors were characterized.
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
20
2
2007
06
22
Effects of Structural Parameters on Mechanical Properties
Polymer/Clay Nanocomposites
اثر عوامل ساختاری بر خواص مکانیکی ناکامپوزیتهای پلیمر - خاکرس
187
195
798
10.22063/jipst.2007.798
FA
محمود
مهرداد شکریه
سید احسان
سنبلستان
Journal Article
2013
03
03
Nanocomposite materials have recently attracted increasing interests in the field of modelling. Finite element modelling can be used for computation of bulk properties of polymer/clay nanocomposites. In this study, by <br />considering the structure of a nano-composite material, a quasi real model is proposed. The model has been used to predict the elastic constants by selection of suitable elements and boundary conditions. The effects of nano-structural parameters on the mechanical properties of a polymer/clay nano-composite are studied. The geometrical overlap of particles, horizontal distance between particles, length of particles and nano-clay volume fraction are defined as functions of the nano-structural parameters and their effects on mechanical properties of nano-composites are studied by a finite element modelling technique.