Farshid Ziaee

Iran Polymer and Petrochemical Institute, Teheran, Tehrān, Iran

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Publications (37)48.55 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Alternative copolymers of acrylic acid (AA) and oligo(ethylene glycol) methyl ether methacryate (475 g/ mol (OEGMA(475))) macromer, having various amounts of two monomers, were synthesized using aqueous solution free radical copolymerization at 50 +/- C with ammonium persulfate (APS) as an initiator. The structures of the copolymers were confirmed by nuclear magnetic resonance (NMR) spectroscopy. In fact, samples with different molar ratios of two monomers in deionized water were prepared and subsequently copolymerization reaction was performed to low conversion levels (below 10%). Monomer reactivity ratios of OEGMA(475), AA pair were estimated using the Finemann-Ross (FR), inverted Finemann-Ross (IFR), Kelen-Tudos (KT), extended Kelen-Tudos (EKT), Mayo-Lewis (ML) and Yezrelieve-Brokhina-Roskin (YBR) graphical methods. The value ranged from 0.908 to 0.963 for r (OEGMA) and from 0.208 to 0.243 for r (AA) depending on conversion percentage and calculation methods of monomer reactivity ratios. In all the cases, r (OEGMA) xr (AA) < 1 and r (OEGMA) > r (AA) indicate that the resulting copolymer has a tendency toward alternation with an azeotropic point in M-OEGMA=0.905. Structural parameters of the copolymers were obtained by calculating the dyad monomer sequence fractions and the mean sequence length.
    Macromolecular Research 12/2014; 22(12):1330-1336. DOI:10.1007/s13233-014-2190-y · 1.68 Impact Factor
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    Dataset: IJPM2011-1
    Farhood Ziaie, Farshid Ziaee
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    ABSTRACT: The solution copolymerization of methacrylic acid (MAA) and ethyl acrylate (EA) was studied by online proton nuclear magnetic resonance spectroscopy (1H NMR) using 2,2′–azobisisobutyronitrile as an initiator in deuterated dimethyl sulfoxide at 60 °C. The chemical compositions of the copolymer and the comonomer concentrations were determined from the conversion of comonomers to copolymer by quantitative in situ NMR monitoring to estimate the reactivity ratios of the comonomers at low conversion. This is a new and easy methodology to analyze radical copolymerization. In this research, it is shown that monomer reactivity ratios can be calculated by data collected only from one initial comonomer mixture composition via online monitoring progress of the copolymerization reaction. The reactivity ratios of MAA and EA are equal to 2.360 and 0.414, respectively. This approach is used to compute the monomer reactivity ratios in a nonlinear integrated form of the copolymerization equation which is described by Mayo and Lewis terminal model. The fairly good agreement between the results and the literature data reported for the emulsion system represent the accuracy of the reactivity ratios calculated by this new approach. The calculated reactivity ratios for emulsion copolymerization are r MAA = 2.040 and r EA = 0.470, and the previous literature data are r MAA = 2.580 and r EA = 0.157.
    Iranian Polymer Journal 09/2013; 22(9). DOI:10.1007/s13726-013-0162-2 · 1.47 Impact Factor
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    ABSTRACT: Free-radical homo- and copolymerization of acryl- amide (AAm) and diallyldimethylammonium chloride (DADMAC) initiated with potassium persulfate (KPS) were performed in the presence of 0.1 M NaCl solution in D 2 O at 50 °C. Online 1 H-NMR kinetic experiments were used to study polymerization kinetics via determination of the individual and overall conversion of the comonomers and compositions of the comonomer mixture and produced copolymer as a function of the reaction time. Reactivity ratios of the AAm and DADMAC were calculated by Mao-Huglin (MH) and extended Kelen- Tudos (KT) methods to be 7.0855±1.3963, 0.1216±0.0301 and 6.9458±2.0113, 0.1201±0.0437 respectively. “Lumped” kinetic parameter (k p k t −0.5 ) was estimated from experimental data. Results showed that k p k t −0.5 value increases by increasing mole fraction of the AAm in the initial reaction mixture. Drift in the comonomer mixture and copolymer compositions with reaction progress was evaluated experimentally and theoretical- ly. Theoretical values were calculated from Meyer-Lowry equa- tion by using reactivity ratios obtained from MH method. A good fitting between the experimental and theoretical values was observed, indicating accuracy of the reactivity ratios esti- mated in the present work. It was found from following changes in the copolymer composition with the comonomer conversion that produced copolymer has a statistical structure.
    Journal of Polymer Research 07/2013; 20(10):239. DOI:10.1007/s10965-013-0239-9 · 1.90 Impact Factor
  • Samaneh Ashenagar, Farshid Ziaee
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    ABSTRACT: A novel generalized least square (GLS) estimator program was employed for determination of styrene (STY)/butyl acrylate (BA) reactivity ratios synthesized by solution copolymerization method. The monomer reactivity ratios as well as the 95 % individual confidence limits were determined by application of conventional linear methods like Finemann–Ross, Ezrielev–Brokhina–Roskin, Joshi–Joshi, Kelen–Tudos, modified Kelen–Tudos, extended Kelen–Tudos and Mao–Huglin. The estimation process was performed by applying techniques based on ordinary least square (OLS) and GLS approaches and the results were compared. The results showed a fairly good agreement between the experimental and calculated copolymer compositions. The model was then successfully validated through handling regression models with error terms that are heteroskedastic or autocorrelation, or both and clearly showed that the model was able to predict the reactivity ratios by accounting response error structure. Based on the copolymer compositions determined by 1H NMR, the reactivity ratios of STY and BA were found to be 0.886634 and 0.216369, respectively, by Mao–Huglin method through the GLS approach, and this new estimation method shows the best linear estimations for the monomer reactivity ratios. The present paper shows a new estimation integral approach for determining the monomer reactivity ratios by different conventional linear methods at low and high conversions in EViews software and the calculated values are discussed in terms of regression models.
    Iranian Polymer Journal 07/2013; 22(7). DOI:10.1007/s13726-013-0147-1 · 1.47 Impact Factor
  • Vahid Najafi, Kourush Kabiri, Farshid Ziaee
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    ABSTRACT: Alcohol absorbents based on poly ethylene glycol methyl ether methacrylate (PEGMEMA) macromer and acrylic acid (AA) were prepared via solution polymerization using trimethyl propane triacrylate (TMPTA) as crosslinker. Swelling capacity of gels was measured in water, ethanol and methanol. Alcohol absorbency was increased with increasing AA content, which can be related to the ability of an AA segment in formation of H-bonding and dissociation of COOH groups to produce of mobile ions. The alcogels absorb ethanol and methanol up to 14.8 and 17.4 g/g, respectively. TG analysis shows that increasing AA content caused an increase of thermal stability of alcogels.
    Polymer-Plastics Technology and Engineering 05/2013; 52(7). DOI:10.1080/03602559.2012.762664 · 1.48 Impact Factor
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    ABSTRACT: The free‐radical polymerization of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS) in aqueous media and in the presence of potassium persulfate (KPS) as a thermal initiator was studied. The 1H‐NMR method was applied to record the reaction data in online gain. The effects of the monomer and initiator concentrations and also the reaction temperature were studied. The order of reaction with respect to the monomer was much greater than unity (1.94). None of the three theories describing an order of reaction higher than unity could predict the AMPS polymerization mechanism in this study. So, a new mechanism is presented. It is suggested that initiation took place through the formation of a complex between the initiator and monomer, and termination occurred not only by a bimolecular reaction but also by a monomolecular reaction. The order with respect to KPS was 0.49; this was consistent with classical kinetic theory. The determined activation energy at the overall rate of reaction was 92.7 kJ mol−1 K−1. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
    Journal of Applied Polymer Science 10/2012; 126(1). DOI:10.1002/app.36379 · 1.64 Impact Factor
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    ABSTRACT: Free-radical polymerization of polyethylene glycol methyl ether methacrylate macromer (PEGMEMA) was studied in aqueous media and in the presence of potassium persulfate (KPS) as water soluble initiator. An on-line nuclear magnetic resonance (NMR) method was applied to record the reaction data and determine the monomer conversion at various times during the polymerization reaction progress. 1H NMR spectrum of reaction mixture containing monomer, initiator and resultant polymer was continuously recorded in NMR instrument with the increase of reaction time. By processing the obtained data from NMR spectrum, the rate equation can be derived and reaction order can be determined with regard to monomer and initiator concentration. In other words, to determine the order of polymerization with regard to the concentration of reactants in free-radical polymerization of PEGMEMA, macromer samples with different amounts of monomer and KPS were prepared and polymerized at 50 °C. Orders of reaction with respect to monomer and initiator molar concentrations were equal to 1.025 and 0.480, respectively. The obtained values for reaction orders in this study were consistent with the classical kinetic rate equation in which the dependency of polymerization rate (R p) on monomer and initiator concentrations was equal to 1 and 0.5, respectively. To measure polymerization activation energy (E a), the effect of reaction temperature on the polymerization rate was investigated and E a = 37.08 kJ/mol was obtained at the temperature range of 40–50 °C.
    Iranian Polymer Journal 10/2012; 21(10). DOI:10.1007/s13726-012-0072-8 · 1.47 Impact Factor
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    ABSTRACT: Alcohol absorbents based on poly(ethylene glycol methyl ether methacrylate) and vinyl phosphonic acid (VPA) were prepared via solution polymerization using poly(ethylene glycol dimethacrylate) macrocrosslinker. Swelling capacity of these materials was measured in water, ethanol and methanol. Alcohol absorbency was increased with increase of VPA content that can be attributed to ability of VPA in formation of H-bonding and disassociation of phosphonic acid group to produce mobile ions. The alcogels could absorb ethanol and methanol up to 15.1 and 17.8 g/g respectively. Thermo-gravimetric analysis showed that increase in VPA concentration increased char yield and decreased the initial decomposition temperature (IDT) due to forming anhydride crosslinks during heating. Based on rheological measurements, the storage modulus was increased with increase in PEGMEMA content. The prepared alcogels were further characterized using FTIR, NMR and DMTA.
    Journal of Polymer Research 06/2012; 19(6). DOI:10.1007/s10965-012-9866-9 · 1.90 Impact Factor
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    ABSTRACT: Free-radical homo- and copolymerization of vinyl acetate (VAc) and n-butyl acrylate (BA) in benzene-d6 were performed by using benzoyl peroxide as an initiator at 70°C. Polymerization kinetic was followed by online 1H NMR kinetic experiments. Significant drift in the comonomer mixture composition with reaction progress was observed. Reactivity ratios of VAc and BA were calculated by terminal unit model (TUM) as well as by simplified penultimate unit model (PUM) with rVAc = 0. It was found that copolymer composition can be described well by the TUM. “Lumped” kinetic parameter ( ) was estimated from experimental data. A good fitting between the theoretical and experimental drifts in the comonomer mixture and copolymer compositions with reaction progress was observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
    Journal of Applied Polymer Science 01/2012; 123(1). DOI:10.1002/app.34510 · 1.64 Impact Factor
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    Farshid Ziaee, Mahdi Samadi Khoshkhoo
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    ABSTRACT: Poly(p-methylstyrene) (Pp-MS) was synthesized at three different temperatures of 50, 150 and 250 °C via bulk thermal polymerization method. The assignment of all stereosequences at triad and pentad levels for two quaternary aromatic carbons and hexad level for methylene carbon was carried out by 13C liquid nuclear magnetic resonance spectroscopy (NMR) in deuterated chloroform at similar conditions. The probability of meso addition (P m) was calculated from second quaternary aromatic carbon and used to predict the relative intensities of methylene and first quaternary aromatic carbon by Bernoullian and first-order Markov statistical models. The results were compared with experimental data. It is shown that the Bernoullian statistics fit better than first-order Markov model for all three samples. The results indicate that P m increases by increasing polymerization temperature. The corresponding P m values determined for synthesized Pp-MSs at 50, 150 and 250 °C were 0.383, 0.392 and 0.404, respectively. It was observed that higher resolutions and better splitting patterns were achievable by increasing the NMR acquisition temperature from 20 to 50 °C. When temperature increased during NMR acquisition, the resolution improved for the first and second quaternary aromatic carbons and methylene carbon, though there was no splitting pattern observed for methyl carbon atom at the para-position of the aromatic ring.
    Iranian Polymer Journal 01/2012; 21(1):21-29. DOI:10.1007/s13726-011-0005-y · 1.47 Impact Factor
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    ABSTRACT: Aqueous free-radical polymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in the presence of potassium persulfate (KPS) as thermal initiator was studied by differential scanning calorimetry (DSC). Effect of temperature, monomer, and initiator concentration on polymerization rate was studied. Obtained recorded data represented order of reaction with respect to monomer greater than unity (1.56). Among the theories presented order of reaction more than one, the gage effect theory in the range of monomer concentration (0.966–2.410 mol/L) had a good agreement with mechanism of AMPS polymerization. The order with respect to KPS was 0.52 which was consistent with classical kinetic theory. Calculated amount of activation energy in overall rate of reaction was 83 kJ/mol K.
    Polymer Bulletin 01/2012; 68(2). DOI:10.1007/s00289-011-0552-6 · 1.49 Impact Factor
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    ABSTRACT: Thermal degradation of polybutadiene (PBD) in anaerobic atmosphere at 250 °C had been studied by carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) before complete crosslinking. In this investigation four types of low molecular weight PBD with different 1,2-vinyl isomer content had been chosen, then pure and mixed samples of PBD were heated in different time periods. 13C NMR spectra showed that two kinds of crosslinking mechanisms occur that both of them produce methyl groups. The first mechanism is a reaction between 1,2-vinyl isomers of two PBD chains, and the second one occurs between 1,2-vinyl isomer of one chain via methylene carbon of cis or trans isomer in another chain. Also 13C NMR results showed that the presence of 1,2-vinyl isomer in the PBD structure is necessary and without it none of the mentioned reactions will occur. Furthermore isomers sequence is another important parameter which affects crosslinking. Results show that cis or trans isomer which is not adjacent to 1,2-vinyl isomer does not take part in crosslinking reaction. Moreover such cis or trans isomer can take part in second mechanism of crosslinking that 1,2-vinyl isomer was attached from head to cis or trans isomer, thus in this arrangement of isomers second mechanism of crosslinking will become dominant rather than first mechanism of crosslinking.
    Polymer Degradation and Stability 10/2011; 96(10):1805-1811. DOI:10.1016/j.polymdegradstab.2011.07.016 · 2.63 Impact Factor
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    ABSTRACT: Tacticity of poly-2-acrylamido-2-methylpropane sulfonic acid samples that were prepared via free radical polymerization in four different solvents, ethanol, dimethyl sulphoxide (DMSO), N, N-dimethylformamide (DMF) and water, were studied by C nuclear magnetic resonance (C-NMR) techniques. In order to change isotacticity, two rare metal triflates, yttrium trifluoromethane sulfonate (Y(OTf)3) and ytterbium trifluoromethane sulfonate (Yb(OTf)3), were used. The stereoregularity of the obtained polymers in DMSO, water and DMF in the presence of the mentioned triflates did not show a noticeable alteration. But isotacticity of the samples prepared in ethanol was increased by about 17% in the presence 75 wt% Y(OTf)3. In the absence of metal triflates, solvents did not have any significant effect on stereocontrol. In addition, the influence of temperature on isotacticity of the prepared samples was studied. By decreasing the reaction temperature, the isotacticity increased slightly.
    Journal of Macromolecular Science Part A 07/2011; 48(7):526-530. DOI:10.1080/10601325.2011.579813 · 0.74 Impact Factor
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    Farhood Ziaie, Farshid Ziaee
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    ABSTRACT: Polymers play a very important role in electrical systems as insulation materials. The microscopic failures occurring in the polymer under working conditions will be important in its required characteristics. In this work we focused on the effects of accelerated aging on the electrical properties of low density polyethylene (LDPE) and crosslinked polyethylene (XLDPE). The samples of LDPE were prepared in sheet form with the thickness of 0.6 ± 0.1 mm and were irradiated under the 10 MeV electron beam of a Rhodotron accelerator at the dose range of 70 to 370 kGy. Then, the samples were stored in an oven at temperature 75°C for 3, 6, 10 and 13 days. Electrical properties such as the breakdown voltage and resistance of the aged samples were measured and compared. Increasing the aging time for unirradiated samples has a serious and moderate influence on their surface resistivity and breakdown voltage, respectively. The results indicated a maximum value for the surface resistance at the optimum radiation absorbed dose, which is approximately 220 kGy for all the samples.
    International Journal of Polymeric Materials 04/2011; 60(4-4):269-275. DOI:10.1080/00914037.2010.504177 · 2.78 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate the effect of three aliphatic esters, ethyl heptanoate, methyl heptanoate, and ethyl nonanoate on the in vitro degradation behavior of in situ forming systems. In situ forming implants based on 33% (w/w) poly (lactide-co-glycolide) (PLGA)/57% (w/w) N-methyl-2-pyrrolidone (NMP)/10% (w/w) esters were prepared after injection of the final formulation in phosphate buffer solution (pH 7.4, 0.2M) at 37°C. The influence of additives on the implants formation, morphology, and also on their in vitro degradation behaviors over a period of 45days was investigated. The degraded matrices were evaluated to determine morphological analysis by SEM and 1H-NMR study. The solution of degradation medium was studied to indicate NMP removal and altering acidity. The results showed that the additives generated a high porous structure and caused the fast phase inversion. However, the 1H-NMR spectra indicated that ester additives remained in the matrices during degradation periods. The results of the acidity study showed that the degradation rates in the matrices containing esters were higher than the control matrix. In addition, it is shown that esters with lower molecular weight have affected the polymer degradation more efficiently than higher molecular weight esters. KeywordsIn situ forming systems–Biodegradation–Solvent removal–Morphology–Poly (lactide-co-glcolide)–Aliphatic esters
    Polymer Bulletin 01/2011; 66(8):1063-1073. DOI:10.1007/s00289-010-0386-7 · 1.49 Impact Factor
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    ABSTRACT: A series of novel self-crosslinkable and biodegradable polymers, poly(hexamethylene carbonate-fumarate) and poly(hexamethylene carbonate) diacrylate, and their amphiphilic copolymers with polyethylene glycol, poly(ethylene glycol fumarate-co-hexamethylene carbonate-fumarate) (PEGF-co-PHMCF), were developed for tissue engineering using propylene oxide as an acid scavenger. The synthesized polymers are white, which makes them more suitable for self-crosslinking via photopolymerization. These novel polymers were fully characterized using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, gel permeation chromatography, differential scanning calorimetry, and rheometry. The cytocompatibility of the photocrosslinked networks were evaluated by [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. These polymers can be used as precursors to prepare polymer networks and scaffolds with controlled hydrophilicity, biodegradability, and mechanical characteristics. Results obtained suggest that these polymers are potentially useful as injectable and photocrosslinkable materials for cell delivery, tissue engineering, and drug delivery applications.
    Journal of Biomedical Materials Research Part A 09/2009; 90(3):830-43. DOI:10.1002/jbm.a.32138 · 2.83 Impact Factor
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    ABSTRACT: Various polybutadienes (PBDs) of low molecular weight were heated below complete crosslinking at 250 °C under anaerobic nonpyrolytic conditions, and the structural changes were investigated. The predominant crosslinking reactions arise from the presence of 1,2-vinyl isomer and the most important one is intermolecular reaction accompanied with methyl group formation. The analysis showed that two crosslinking types as well as two types of methyl groups have been produced in which one was the result of 1,2-vinyl isomer of one chain crosslinked via methylene carbon of another chain of cis or trans isomer, and the second methyl group was the product of the reaction between 1,2-vinyl isomers of two PBD chains. Chain scission also occurred in two pathways due to the presence of 1,2-vinyl isomer, scission at two adjacent 1,2-vinyl isomer and scission at adjacent 1,2-vinyl with cis or trans isomer giving rise to methyl carbons.
    Polymer Degradation and Stability 09/2009; 94(9-94):1336-1343. DOI:10.1016/j.polymdegradstab.2009.06.002 · 2.63 Impact Factor
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    ABSTRACT: One of the methods of polymeric material modification is based on the irradiation with accelerated ions. Chemical etching of ion tracks in polymers is a method which is widely used in the fabrication of micro/nano-structures with pre-determined characteristics. For the present study polyvinyl butyral (PVB) porous membrane was prepared by track-etching technique. Commercially available PVB film was irradiated by 30 MeV energy protons to form latent tracks, and then etched chemically by potassium hydroxide (KOH) with the different normalities. The etching rate of PVB was related to the concentration of etching reagent, temperature and time. The porous size and shape were investigated by scanning electron microscope (SEM) after and before etching. Relationships in between the etching rate and the etching parameters were established from experimental data, and can be used to control the pore size of PVB track-etch membrane. The Pore sizes and their structures were evaluated by optical microscope (OM) and scanning electron microscope (SEM). The results have shown the micro/nano-pores formation in the PVB films. The physico-chemical properties of the irradiated samples were investigated and compared with the un-irradiated one using the FTIR and DSC and DTG systems, as well.
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    ABSTRACT: Photocrosslinkable and biodegradable polymeric networks were formulated based on N-vinyl pyrrolidone-poly(epsilon-caprolactone fumarate) (NVP/PCLF) compositions for hard tissue engineering applications using a new proton scavenger, propylene oxide (PO). The synthesized macromers; were obtained as a white clear paste with no colorization. The obtained macromers were thoroughly characterized using spectroscopic (NMR and FT-IR) and chromatographic (gel permeation chromatography (GPC)) techniques. Photocrosslinking of the PCLF/NVP compositions was achieved using camphorquinone and dimethyl toluidine (DMT) as a photoinitiator system. The cytocompatibility of the macromers and their corresponding networks were evaluated via MTT assay. Characterization of the networks indicated the importance of NVP content on the network properties. Sol fraction studies indicated that more than 90% of the PCLFs were crosslinked over the studied range of PCLF/NVP compositions; however most of the NVP above a stoichiometric ratio of one NVP to fumerate unit remained unreacted. It was also found that in the concentrations more than 10% NVP, the unreacted NVP monomer neither participated in the crosslinking reaction nor homopolymerized to poly(vinyl pyrrolidone) (PVP). The elastic modulus (G') and estimated molecular weight between crosslinks also confirmed that at the higher NVP content the PCLF photocrosslinking was hindered. Copyright (C) 2008 John Wiley & Sons, Ltd.
    Polymers for Advanced Technologies 12/2008; 19(12):1828-1838. DOI:10.1002/pat.1207 · 1.96 Impact Factor

Publication Stats

151 Citations
48.55 Total Impact Points

Institutions

  • 2004–2014
    • Iran Polymer and Petrochemical Institute
      • • Department of Novel Drug Delivery Systems
      • • Department of Polymer Science
      Teheran, Tehrān, Iran
  • 2006–2007
    • Amirkabir University of Technology
      • Department of Biomedical Engineering
      Teheran, Tehrān, Iran