پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
24
2
2012
12
29
Nano Clay Effect on Morphology, Mechanical Properties and Water Absorption of Vinyl Ester-Based Nanocomposites
اثر نانوخاک رس بر شکلشناسی، خواص مکانیکی و جذب آب نانوکامپوزیتهای بر پایه رزین وینیل استر
83
92
580
10.22063/jipst.2012.580
FA
عفت
جودار
محمدحسین
بهشتی
محمد
عطایی
Journal Article
2012
12
29
Nanocomposites based on vinyl ester resin (Derakane 470-300) and nano clay (Cloisite 30B) were prepared. The effect of clay content of 1, 3 and 5% (by weight) on the morphology, mechanical properties and water absorption of vinyl ester resin nanocomposites were studied. The nanocomposites were characterized using small-angle X-ray scattering (SAXS), feld emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and mechanical property measurements. SAXS and TEM images revealed a fully exfoliated morphology for clay content of 1 and 3% and an intercalated morphology for clay content 5%. Mechanical tests results showed that the vinyl ester nanocomposites have signifcantly better mechanical properties than neat vinyl ester resin. It is also found that water absorption drops in all specimens containing nano caly, and it is reduced to half its value with respect to the neat resin when the Cloisite 30B content is only 1%. The hardness of vinyl ester samples increased from 40 to 57 Barcol (approximately 43% increase) with by incorporating nanoclay of 1%.
http://jips.ippi.ac.ir/article_580_008271dd0dc1e82fd5220de66cbece61.pdf
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
24
2
2012
12
29
Sample Thickness and Structural Changes in Thermo-Oxidative Degradation of Polybutadiene
اثر ضخامت نمونه و تغییر ساختار در تخریب گرمایی اکسایشی پلیبوتادیان
93
99
581
10.22063/jipst.2012.581
FA
فرشید
ضیایی
آیدا
شوشتری زاده
Journal Article
2012
12
29
The thermo-oxidative degradation of two viscous liquid resins of 1,2- poly-butadiene (1,2-PBD) and 1,4- polybutadiene (1,4-PBD) have been studied by differential scanning calorimetry (DSC) and thermogravimetry analy-sis (TGA). To study further, the effect of flm thickness on oxidation kinetics was periodically studied by tracing the weight of the samples to make comparison with DSC results at constant temperature of 100°C under atmospheric pressure. Finally, the structural changes of 1,4-PBD were investigated by carbon-13 nuclear magnetic resonance spectroscopy (13C NMR). The results from 13C NMR from 1,4-PBD show that after heat treatment new carbon peaks are obtained for an epoxide carbon at 58.6 ppm, an adjacent methylene carbon of epoxide group at 24.0 ppm and a peroxide methine carbon group at 86.7 ppm. The results from TGA and DSC studies conclude that 1,2-PBD do not age due to its structure. The results from NMR spectroscopy indicate that besides structural changes, increase in mass is due to radical addition to double bond while, epoxide groups are one of major products of thermal oxidation which can be identifed from their 13 C NMR peaks.
http://jips.ippi.ac.ir/article_581_9adf5c700d61213c67afd2ca4f4accc4.pdf
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
24
2
2012
12
29
Synthesis of Poly(styrene-co-butyl acrylate)/Clay Nanocomposite via In Situ AGET ATRP
سنتز نانوکامپوزیت پلی(استیرنـ کوـ بوتیل آکریلات) - خاک رس به روش پلیمرشدن رادیکالی انتقال اتم درجا با استفاده از فعالکننده تولید شده با انتقال الکترون
101
112
582
10.22063/jipst.2012.582
FA
لیلا
احمدیان اعلم
وحید
حدادی اصل
حسین
روغنی ممقانی
لیلا
حاتمی
مهدی
سلامی کلجاهی
Journal Article
2012
12
29
Poly(styrene-co-butyl acrylate)/clay nanocomposites were synthesized via in situ atom transfer radical polymerization using activators generated by electron transfer in the presence of a montmorillonite ion-exchanged with mixed surfactants of dodecyl trimethyl ammonium bromide and vinyl trimethyl ammonium chloride. The living nature of polymerization is confrmed by occurrence of narrow molecular weight distribution of the nanocomposites in which copolymers with polydispersity index of about 1.13-1.15 were obtained. Partial exfoliation of clay layers in the copolymer matrix was demonstrated by XRD patterns and further studies of TEM images. Thermogravimetric analysis (TGA) results demonstrated a slight increase in <br />the thermal stability of nanocomposites in comparison with the neat copolymer. DSC results indicated a decrease in the glass transition temperature (Tg) of nanocomposites by the addition of clay content which are attributed to low molecular weights of the copolymers and weaker interactions between polymer chains. The chemical structure and composition of copolymers was identifed by 1H NMR analysis.
http://jips.ippi.ac.ir/article_582_864ef600fb5489d81899912b8fcb5e24.pdf
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
24
2
2012
12
29
Synthesis of Poly(para-phenylene terephthalamide) and Preparation of Short Fibers: Effect of Sodium Sulphate on the Fibers
سنتز پلی پارافنیلن ترفتالامید و ساخت الیاف با طول کم: بررسی اثر نمک سدیم سولفات بر این الیاف
113
120
583
10.22063/jipst.2012.583
FA
محمدعلی
سمسارزاده
آرزو
دادخواه
Journal Article
2012
12
29
Kevlar is one of the fbers which is used in heavy industrial productions such as, shipping, military and weaving for reinforcement of composites. Initial polymer of Kevlar or poly(para-phenylene terephthalamide) is an oriented liquid crystal polymer. Existence of aromatic group in the main chain leads to formation of rigid-rod molecules in the polymer, high strength and high modulus in it is fbers. Impurities in the polymer lead to decrease in fbers performance. In this research, poly(para - phenylene terephthalamide) was synthesized from polycondensation of phenylene diamine and terephthaloyl dichloride in n-methyl pyrrolidone and calcium chloride (NMP-CaCl2) solution. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) tests were carried out to characterize chemical bonds and crystalline plates of the polymer, respectively. Concentrated sulfuric acid is a solvent of poly(phenylene terephthalate) therefore, this polymer was dissolved in concentreated sulfuric acid (96%) and the polymer solution was injected into the cylindrical tank contain water. Sulfuric acid was transferred into water and the polymer was solidifed. After solidifcation, tensile force of vortex led to orientation of rigid-rod polymer molecules in direction of water rotation and long fbers were formed from the polymer. The fbers were broken to short fbers by the same force of vortex. The short fbers were dried. SEM images showed the regular particles on the surface of fbers. Results of FTIR and XRD proved that the regular particles are sodium sulphate salt. The effect of sodium sulphate salt as an impurity on the short fbers was studied.
http://jips.ippi.ac.ir/article_583_f2d5544e80c879cb9d826ba027a35517.pdf
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
24
2
2012
12
29
Mechanical and Anti-bacterial Properties of Dental Adhesive Containing Diamond Nanoparticles
بررسی خواص مکانیکی و ضدباکتری چسب دندانی حاوی نانوذرات الماس
121
131
584
10.22063/jipst.2012.584
FA
زینب
عبادی
محمد
عطایی
مرتضی
ابراهیمی
Journal Article
2012
12
29
The effect of nanoparticle diamond incorporated in an experimental dental adhesive formulation is valuated by examining the mechanical properties and shear bond strength of the system. Diamond nanoparticles were incorporated into the dentin adhesive system in different concentrations of 0, 0.05, 0.1, 0.2, 0.5, and 1.0 weight percentages. The suspensions were ultrasonicated to facilitate the nano-particle dispersion in an adhesive solution containing ethanol, bis-GMA, UDMA, TMPTMA, HEMA and photo-initiator system. Diametral tensile strength, fexural strength, fexural modulus, depth of cure and microshear bond strength of the adhesive system were measured. The adhesive-dentin interface was then observed by scanning electron microscopy. The results were analyzed using one-way ANOVA at a signifcant level of P>0.05. No signifcant difference was observed between the diametral tensile strength of the adhesive. At nanoparticle content level of 0.1% (by wt), however, 85% increase in fexural strength and 13% enhancement in fexural modulus were observed. Microshear bond strength test revealed 70% and 79% improvements of adhesion force in systems containing 0.1% and 0.2% nanoparticles, respectively. Although the neat diamond nanoparticles revealed antibacterial activity, the adhesive containing different percentages of the nano particles did not show any antibacterial activities when tested against, Staphilococcus Aureus, Staphilococcus Streptococcus, Staphilococcus ephidermidis, Saprophyticus, Enterococcus faecalis bacteries.
http://jips.ippi.ac.ir/article_584_9431f9d3e85f2dacf59dfac05fc0cfae.pdf
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
24
2
2012
12
29
Non-linear Behavior of Polymer Based Composite Laminates under Cyclic Thermal Shock and Its Effects on Residual Stresses
رفتار غیرخطی چندلایهایهای کامپوزیتی پایه پلیمری در اثر شوک گرمایی چرخهای و آثار آن بر تنشهای پسماند
133
140
585
10.22063/jipst.2012.585
FA
احمدرضا
قاسمی
رسول
باقرصاد
محمدرضا
وزیری سرشک
Journal Article
2012
12
29
The residual stresses in composite laminates depend on several factors including the conditions of fabricating process, property of materials, direction and lay-ups of the layers. However the thermo-elastic behavior of composite is one of the most important parameters affecting the magnitude of residual stresses. The elastic properties and residual stresses do not remain constant under cyclic thermal loading and vary in a non-linear manner. The study of these non-linear variations of modulus and strength and their effects on residual stresses in laminates while experiencing thermal load cycles is the main goal of this paper. An experimental device is designed and manufactured conveniently to exert defned thermal load cycles with different temperatures and cycle time on composite laminates. Then orthotropic glass-epoxy composite laminates made by hand lay-up are tested under cyclic thermal loading. The elastic modulus and fracture strength of the samples are measured before and after experiencing defned number of thermal shocks. The residual stresses in composite laminates are calculated and compared based on the actual behavior of composite and by means of a modifed classical laminate theory. The results of this study demonstrate that the non-linear behavior of composites infuences the residual stresses signifcantly. In addition, if the sample becomes more brittle, the residual strains remain constant; while the elasticity modulus and residual stresses decrease.
http://jips.ippi.ac.ir/article_585_d7ed8f8bb6fdbf6398981128a15b664d.pdf
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
24
2
2012
12
29
Kinetics of Waterborne Alkyd/Acrylic Hybrid Resin Free Radical Polymerization by Two Systems of Redox and Thermal Initiators
بررسی سینتیک پلیمرشدن رادیکالی رزین هیبرید آلکید- آکریلیک آب پایه با استفاده از آغازگرهای گرمایی و اکسایشی- کاهشی
141
152
586
10.22063/jipst.2012.586
FA
شیرین
مددی
علی اکبر
یوسفی
0000-0002-5118-5063
الهام
کشمیری زاده
Journal Article
2012
12
29
Kinetics of radical polymerizations of waterborne alkyd/acrylic hybrid resin via batch mini-emulsion technique was studied using redox initiators (TBHP/Fe2+/EDTA/AsAc and TBHP/Fe2+/EDTA/SFS) at relatively low <br />temperatures and thermal initiators (BPO, KPS and AIBN) at higher temperatures to seek the most suitable initiator system. At the end of all reactions the unreacted monomer content was reduced using post-polymerization technique; consequently, leading to increased monomer conversion and flm formation with improved properties. The kinetics of mini-emulsion polymerization showed that in all redox initiator systems <br />(Fe2+ catalyst + EDTA chelating agent), the radials are produced at relatively low temperature with more effcient control of the reactor temperature. It was found that at 45°C TBHP/Fe2+/EDTA/SFS redox initiator system leads to 98% monomer conversion, a much higher rate than that of systems involved thermal initiators.
http://jips.ippi.ac.ir/article_586_add86ae0a77205ebe3b672333793caaf.pdf
پژوهشگاه پلیمر و پتروشیمی ایران با همکاری انجمن پلیمر ایران
مجله علوم و تکنولوژی پلیمر
10163255
24
2
2012
12
29
Design, Construction, and Evaluation of Rubber Friction Tester
طراحی، ساخت و ارزیابی دستگاه اندازهگیری ضریب اصطکاک لاستیک
153
164
587
10.22063/jipst.2012.587
FA
مهدی
رزاقی کاشانی
0000-0002-4207-8573
رسول
اسمعیلی نیسیانی
Journal Article
2012
12
29
Coeffcient of friction (COF) for rubber parts is one of the key parameters in their interaction with solid rough surfaces (micrometer to millimeter scales), such as tire-road interactions. COF of rubber depends on viscoelastic properties of rubber, roughness characteristics of the counter-part surface, and process variables such as contact nominal pressure and sliding speed. Due to the need for measuring COF for rubber, a new friction tester, with continuous variation of nominal pressure and sliding speed, was designed and constructed in order to assess the effect of above mentioned parameters. Tire tread compounds, as the most common rubber part in the feld of rubber tribology, was used for this purpose. Viscoelastic properties of compounds were varied by changing composition of styrene-butadiene rubber (SBR) and butadiene rubber (BR) in the blend. Effect of surface roughness was evaluated by using silicon-carbide papers with different roughness parameters. By statistical analysis it was shown that the designed friction tester has high accuracy in measuring the coeffcient of friction of rubber and differentiating the effective parameters. Increasing the nominal pressure led to reduction of COF and increase in sliding speed forced it through a maximum. In conclusion, the loss factor of the compound and asymmetry in roughness distribution of the counter-surface are considered as the most effective parameters on COF of rubber.
http://jips.ippi.ac.ir/article_587_e72bdee8887161dbd2b745ce3ac518c7.pdf