@article{afshari_chen_kotek_2012, title={Relationship between tensile properties and ballistic performance of poly(ethylene naphthalate) woven and nonwoven fabrics}, volume={125}, ISSN={["1097-4628"]}, DOI={10.1002/app.36442}, abstractNote={AbstractIn this study, we investigated the effect of tensile properties of poly(ethylene naphthalate) (PEN) yarns on the ballistic performance of woven and nonwoven soft and composite armors. The results of ballistic tests of PEN armors were compared with Kevlar 49 armors as a reference. Based on these results, the Cunniff's equation was revised by removing the fiber elongation at break to predict the relationship between tensile properties and ballistic performances of PEN fibers. The calculations showed that by increasing tenacity of PEN fibers from 8.5 g/den (commercial product) to 12.5 g/den (strongest up to date PEN fibers produced by a novel melt spinning process discovered by our research group), the weight ratio of PEN to Kevlar 49 decreased from 1.8 to 1.35 with the same ballistic performance. Contrary to the results of the soft armors, composite armors made of high modulus PEN woven fabric showed a 17% lower ballistic resistance compared to the composite armor made of low modulus PEN woven fabric. The results of ballistic tests indicated that high tenacity PEN fibers produced in this research could have potential in soft and composite armors, and high velocity impact applications or improve performance of PEN in its current applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012}, number={3}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Afshari, Mehdi and Chen, Peng and Kotek, Richard}, year={2012}, month={Aug}, pages={2271–2280} }
 @misc{kalaee_akhlaghi_nouri_mazinani_mortezaei_afshari_mostafanezhad_allahbakhsh_dehaghi_amirsadri_et al._2011, title={Effect of nano-sized calcium carbonate on cure kinetics and properties of polyester/epoxy blend powder coatings}, volume={71}, ISSN={["1873-331X"]}, DOI={10.1016/j.porgcoat.2011.02.006}, abstractNote={Today's strict environmental laws pose significant challenges for coating's formulators to look for eco-friendly products. Powder coatings, particularly polyester/epoxy blends have demonstrated their ability as alternatives to traditional solvent-borne coatings. Recently, the use of nanoparticles such as nano-CaCO3 (nCaCO3) has been suggested as a beneficial strategy towards powder coating application with improved properties. Here, we study the effect of nCaCO3 on morphology, cure behavior, adhesion and hardness of polyester/epoxy systems. The nanoparticles shape, size and dispersion state were investigated through X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. Furthermore, isothermal cure characterization of the neat and filled systems was performed using a torque rheometer. The most important finding based on the rheological studies was the catalytic effect of nCaCO3 on cure reaction of polyester/epoxy, leading to the shorter curing time. Moreover, the kinetic analyses of rheograms revealed a marked decrease in the activation energy of the cure process upon raising nCaCO3 content. Interestingly, pull-off adhesion and hardness tests showed that the hardness and adhesion strength were dramatically increased by the addition of nCaCO3 into the polyester/epoxy system compared to pure blend resin. Therefore, considering the strong competition in powder coating market, the use of nCaCO3 as a commercial and inexpensive nanofiller is necessary not only to reduce the dwell time which has benefits in terms of the energy consumption and economics, but also to improve the performance of final polyester/epoxy coating.}, number={2}, journal={PROGRESS IN ORGANIC COATINGS}, author={Kalaee, Mohammadreza and Akhlaghi, Shahin and Nouri, Ali and Mazinani, Saeedeh and Mortezaei, Mehrzad and Afshari, Mehdi and Mostafanezhad, Dariush and Allahbakhsh, Ahmad and Dehaghi, Hamidreza Aliasgari and Amirsadri, Ali and et al.}, year={2011}, month={Jun}, pages={173–180} }
 @article{akhlaghi_sharif_kalaee_elahi_pirzadeh_mazinani_afshari_2012, title={Effect of stabilizer on the mechanical, morphological and thermal properties of compatibilized high density polyethylene/ethylene vinyl acetate copolymer/organoclay nanocomposites}, volume={33}, ISSN={["0261-3069"]}, DOI={10.1016/j.matdes.2011.07.044}, abstractNote={In this work, the effects of a phosphate containing stabilizer on the mechanical, morphological and thermal properties of a compatibilized high density polyethylene (HDPE)/ethylene vinyl acetate (EVA) blend containing an ammonium quaternary salts modified montmorillonite were studied from both statistical and experimental aspects. According to the results obtained from simultaneous implementation of analysis of variance (ANOVA) and mean effect assessment, the formulations designed based on the optimized coupling of stabilizer into organoclay/compatibilizer system exhibited the highest tensile properties among the prepared samples. From experimental point of view, the d-spacing measurements and microscopy observations through X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively, revealed that the stabilizer not only favored the penetration of the polymeric chains between the silicate layers but also contributed to provide finer dispersion of the minor phase in the matrix. Thermal characterizations using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the stabilizer could play a role in prevention of the organic modifier of the nanoclay to undergo thermo-oxidative degradation by hindering the SN2 nucleophilic substitution reactions between alkyl ammonium chains and oxygen molecules. This, we believe, is responsible for the properties enhancement, since the protective role of stabilizer might inhibit the formation of destructive degradation products which could collapse the organoclay tactoids and also deactivate the anhydride groups of the compatibilizer.}, journal={MATERIALS & DESIGN}, author={Akhlaghi, Shahin and Sharif, Alireza and Kalaee, Mohammadreza and Elahi, Alireza and Pirzadeh, Mohammadhadi and Mazinani, Saeedeh and Afshari, Mehdi}, year={2012}, month={Jan}, pages={273–283} }
 @article{akhlaghi_kalaee_jowdar_nouri_mazinani_afshari_famili_amini_behrouz_2012, title={Simultaneous study of cure kinetics and rheology of montmorillonite/vinyl ester resin nanocomposites}, volume={23}, ISSN={["1099-1581"]}, DOI={10.1002/pat.1912}, abstractNote={AbstractIn this work, the effect of quaternary ammonium salt containing nanoclay content (1–5 wt%) on phase morphology, rheology, cure kinetics, and mechanical properties of the vinyl ester resin (VER)‐based nanocomposites was studied. The morphological characterization including d‐spacing measurement, microscopy observation and phase‐height image processing were performed on the prepared nanocomposites using small angel X‐ray scattering (SAXS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). According to the results obtained from these techniques, it was concluded that an intercalated morphology existed for all the nanocomposites. The kinetic analyses of the isothermal curing followed by storage modulus obtained from the rheometry experiments are shown to be an affective rheological characteristic to investigate the cure behavior of VER/clay nanocomposites. In addition, the most important finding regarding the effect of nanoclay on the cross‐linking behavior of VER systems lays on the chemisorption and physisorption of the reacting monomers and initiator molecules on the nanoclay platelets surface which is found to be responsible for the retardation of the cure reaction caused by organoclay. Eventually, the mechanical characterizations were performed through the tensile, flexural and impact analysis tests. In this case, a considerable improvement of the bulk mechanical responses such as tensile and flexural strengths and also the corresponding moduli were observed for the nanocomposites. Copyright © 2011 John Wiley & Sons, Ltd.}, number={3}, journal={POLYMERS FOR ADVANCED TECHNOLOGIES}, author={Akhlaghi, Shahin and Kalaee, Mohammadreza and Jowdar, Effat and Nouri, Ali and Mazinani, Saeedeh and Afshari, Mehdi and Famili, Mohamadhosein Navid and Amini, Navid and Behrouz, Toktam}, year={2012}, month={Mar}, pages={534–544} }
 @article{scott_afshari_kotek_saul_2011, title={The promotion of axon extension in vitro using polymer-templated fibrin scaffolds}, volume={32}, ISSN={0142-9612}, url={http://dx.doi.org/10.1016/j.biomaterials.2011.03.037}, DOI={10.1016/j.biomaterials.2011.03.037}, abstractNote={Biomaterial nerve cuffs are a clinical alternative to autografts and allografts as a means to repair segmental peripheral nerve defects. However, existing clinical biomaterial constructs lack true incorporation of physical guidance cues into their design. In both two- and three-dimensional systems, it is known that substrate geometry directly affects rates of axon migration. However, the ability to incorporate these cues into biomaterial scaffolds of sufficient porosity to promote robust nerve regeneration in three-dimensional systems is a challenge. We have developed fibrin constructs fabricated by a sacrificial templating approach, yielding scaffolds with multiple 10–250 μm diameter conduits depending on the diameter of the template fibers. The resulting scaffolds contained numerous, highly aligned conduits, had porosity of ∼ 80%, and showed mechanical properties comparable to native nerve (150–300 kPa Young's modulus). We studied the effects of the conduit diameters on the rate of axon migration through the scaffold to investigate if manipulation of this geometry could be used to ultimately promote more rapid bridging of the scaffold. All diameters studied led to axon migration, but in contrast to effects of fiber diameters in other systems, the rate of axon migration was independent of conduit diameter in these templated scaffolds. However, aligned conduits did support more rapid axon migration than non-aligned, tortuous controls.}, number={21}, journal={Biomaterials}, publisher={Elsevier BV}, author={Scott, John B. and Afshari, Mehdi and Kotek, Richard and Saul, Justin M.}, year={2011}, month={Jul}, pages={4830–4839} }
 @article{chen_afshari_cuculo_kotek_2009, title={Direct Formation and Characterization of a Unique Precursor Morphology in the Melt-Spinning of Polyesters}, volume={42}, ISSN={["1520-5835"]}, DOI={10.1021/ma900669r}, abstractNote={chinese acad sci, ningbo inst mat technol & engn, ningbo 315201, zhejiang, peoples r china.}, number={15}, journal={MACROMOLECULES}, author={Chen, Peng and Afshari, Mehdi and Cuculo, John A. and Kotek, Richard}, year={2009}, month={Aug}, pages={5437–5441} }
 @misc{afshari_sikkema_lee_bogle_2008, title={High performance fibers based on rigid and flexible polymers}, volume={48}, ISSN={["1558-3716"]}, DOI={10.1080/15583720802020129}, abstractNote={This chapter covers recent developments in the production of well established high performance fibers such as Kevlar, PBO, Spectra and Dyneema fibers and depicts a new super strong M5. The latter fibers have the modulus of 330GPa and tenacity of 5GPa. DuPont de Nemours is currently developing commercial M5 fibers and yarns. A very interesting monomer namely, 2,5‐dihydroxyterephthalic is used for making poly{2,6‐diimidazo[4,5‐b:4′,5′‐e]pyridinylene‐1,4‐(2,5‐dihydroxy)phenylene} (PIPD). The unique feature of the polymer is that the two hydroxyl groups (on terephthalic acid) can form intermolecular hydrogen bonds and therefore fibrillation, that is often a problem for aramid fibers, is practically eliminated. As a result, M5 fibers have the highest compressive strength among synthetic fibers. Exploratory evaluation of the UV stability of M5 indicated excellent performance in that field. The mechanical properties of the new fiber make it competitive with carbon fiber in most applications ‐ in light, slender, load bearing stiff advanced composite components and structures.}, number={2}, journal={POLYMER REVIEWS}, author={Afshari, Mehdi and Sikkema, Doetze J. and Lee, Katelyn and Bogle, Mary}, year={2008}, pages={230–274} }
 @article{gupta_saquing_afshari_tonelli_khan_kotek_2009, title={Porous Nylon-6 Fibers via a Novel Salt-Induced Electrospinning Method}, volume={42}, ISSN={["1520-5835"]}, DOI={10.1021/ma801918c}, abstractNote={Porous nylon-6 fibers are obtained from Lewis acid-base complexation of gallium trichloride (GaCl3) and nylon-6 using electrospinning followed by GaCl3 removal. DSC and FTIR results reveal that the electrospun fibers, prior to GaCl3 removal, are amorphous with no hydrogen bonds present between nylon-6 chains. GaCl3 being a Lewis acid interacts with the Lewis base sites (CdO groups) on the nylon-6 chains, thereby preventing the chains to crystallize via intermolecular hydrogen bonding. Subsequent removal of GaCl3 from the as-spun fibers by soaking the electrospun web in water for 24 h leads to the formation of pores throughout the fibers. While the average fiber diameter remains effectively the same after salt removal, the average surface area increases by more than a factor of 6 for the regenerated fibers. The dual use of a metal salt (Lewis acid) to (a) facilitate fiber formation by temporary removal of polymer interchain interactions and (b) act as a porogen provides a facile approach to obtain porous fibers via electrospinning.}, number={3}, journal={MACROMOLECULES}, author={Gupta, Amit and Saquing, Carl D. and Afshari, Mehdi and Tonelli, Alan E. and Khan, Saad A. and Kotek, Richard}, year={2009}, month={Feb}, pages={709–715} }
 @article{afshari_gupta_wook_kotek_tonelli_vasanthan_2008, title={Properties of Lewis acid-base complex of nylon 6,6: Route to high performance fibers}, volume={49}, journal={Polymer}, author={Afshari, M. and Gupta, A. and Wook, D. J. and Kotek, R. and Tonelli, A. and Vasanthan, N.}, year={2008}, pages={1297–1304} }
 @article{afshari_gupta_jung_kotek_tonelli_vasanthan_2008, title={Properties of films and fibers obtained from Lewis acid-base complexed nylon 6,6}, volume={49}, ISSN={["0032-3861"]}, DOI={10.1016/j.polymer.2008.01.038}, abstractNote={A nylon 6,6 complex with GaCl3 in nitromethane (4–5 wt% nylon 6,6) was prepared at 50–70 °C over 24 h for the purpose of disrupting the interchain hydrogen bonding between nylon 6,6 chains, resulting in amorphous nylon 6,6, and increasing the draw ratio for improving the performance of nylon 6,6 fibers. After drawing, complexed films and fibers were soaked in water to remove GaCl3 and regenerate pure nylon 6,6 films and fibers. FTIR, SEM, DSC, TGA, and mechanical properties were used for characterization of the regenerated nylon 6,6 films and fibers. The amorphous complexed nylon 6,6 can be stretched to high draw ratios at low strain rates, due to the absence of hydrogen bonding and crystallinity in these complexed samples. Draw ratios of 7–13 can be achieved for complexed fibers, under low strain rate stretching. This study indicates that nylon 6,6 fibers made from the GaCl3 complexed state, using a high molecular weight polymer, can reach initial moduli up to 13 GPa, compared to initial moduli of 6 GPa for commercial nylon 6,6 fibers. Lewis acid–base complexation of polyamides provides a way to temporarily suppress hydrogen bonding, potentially increasing orientation while drawing, and following regeneration of hydrogen bonding in the drawn state, to impart higher performance to their fibers.}, number={5}, journal={POLYMER}, author={Afshari, M. and Gupta, A. and Jung, D. and Kotek, R. and Tonelli, A. E. and Vasanthan, N.}, year={2008}, month={Mar}, pages={1297–1304} }
 @article{ojha_afshari_kotek_gorga_2008, title={Morphology of electrospun nylon-6 nanofibers as a function of molecular weight and processing parameters}, volume={108}, ISSN={["1097-4628"]}, DOI={10.1002/app.27655}, abstractNote={AbstractIn the present study, the morphology and mechanical properties of nylon‐6 nanofibers were investigated as a function of molecular weight (30,000, 50,000, and 63,000 g/mol) and electrospinning process conditions (solution concentration, voltage, tip‐to‐collector distance, and flow rate). Scanning electron micrographs (SEM) of nylon‐6 nanofibers showed that the diameter of the electrospun fiber increased with increasing molecular weight and solution concentration. An increase in molecular weight increases the density of chain entanglements (in solution) at the same polymer concentration; hence, the minimum concentration to produce nanofibers was lower for the highest molecular weight nylon‐6. The morphology of electrospun fibers also depended on tip‐to‐collector distance and applied voltage concentration of polymer solution as observed from the SEM images. Trends in fiber diameter and diameter distribution are discussed for each processing variable. Mechanical properties of electrospun nonwoven mats showed an increase in tensile strength and modulus as a function of increasing molecular weight. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008}, number={1}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Ojha, Satyajeet S. and Afshari, Mehdi and Kotek, Richard and Gorga, Russell E.}, year={2008}, month={Apr}, pages={308–319} }
 @inbook{afshari_kotek_jung_tonelli_2007, title={Producing fibers by electrospinning}, ISBN={9781420044492}, booktitle={Nanofibers and nanotechnology in textiles}, publisher={Cambridge: Woodhead Publishing, in association with The Textile Institute}, author={Afshari, M. and Kotek, R. and Jung, D. and Tonelli, A.}, editor={P.J. Brown and Stevens, K.Editors}, year={2007} }
 @inbook{afshari_wook_kotek_tonelli_2007, title={Producing polyamide nanofibers by electrospinning}, ISBN={9781845691059}, DOI={10.1201/9781439823965.ch4}, booktitle={Nanofibers and nanotechnology in textiles}, publisher={Cambridge: Woodhead Publishing}, author={Afshari, M. and Wook, D. J. and Kotek, R. and Tonelli, A.}, editor={P.J. Brown and Stevens, K.Editors}, year={2007}, pages={71–87} }
 @inproceedings{lee_onori_afshari_cuculo_kotek_2007, title={Spinning of semi-rigid polymers}, ISBN={9788391101261}, booktitle={Proceedings of IX international scientific conference: IMTEX 2007, Lo?dz?-Poland, October 8-9, 2007}, publisher={Lo?dz? : Katedra Architektury Tekstylio?w Politechniki Lo?dzkiej}, author={Lee, H. J. and Onori, J. and Afshari, M. and Cuculo, J. and Kotek, R.}, editor={Krucin?ska, I. and Zaja?czkowski, J.Editors}, year={2007} }
 @article{afshari_kotek_gupta_kish_dast_2005, title={Mechanical and structural properties of melt spun polypropylene/nylon 6 alloy filaments}, volume={97}, ISSN={["1097-4628"]}, DOI={10.1002/app.21772}, abstractNote={AbstractInvestigated in the present study are the physical properties, morphology, and structure of PP/N6 alloy filaments (10, 20 wt % N6) made with or without PP‐g‐MAH as compatibilizer. The alloy filaments produced at the take‐up speeds of 300 and 800 m/min were drawn with draw ratio of 3.5 and 2, respectively. Stress–strain curves of PP and alloy filaments show ductile and brittle behavior, respectively. It is suggested that the brittle behavior of alloy filaments is due to the presence of microvoids or micropores at the interface of PP and N6; these lead to stress concentration and thus to a decrease in tenacity, modulus, and elongation at break. Effects of the blending of N6 with PP on birefringence and crystalline and amorphous orientation factors of the composite filaments are studied. The amorphous orientation factor, fam, of PP was found to increase with an increase in the amount of N6. The alloy filaments behaved like isostrain materials and most of the force in spinning and drawing was born by the PP phase. The presence of N6 fibrils helped to orient PP chain molecules in amorphous regions. However, the crystalline factor, fc, of PP decreased with the increase in nylon fraction. This means the presence of the crystals of N6 caused a decrease in the orientation of the PP crystals. LSCM micrographs of the filament showed the presence of matrix–fibril morphology with the N6 fibrils oriented along the axis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 532–544, 2005}, number={2}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Afshari, M and Kotek, R and Gupta, BS and Kish, MH and Dast, HN}, year={2005}, month={Jul}, pages={532–544} }
 @article{afshari_kotek_kish_dast_gupta_2002, title={Effect of blend ratio on bulk properties and matrix-fibril morphology of polypropylene/nylon 6 polyblend fibers}, volume={43}, ISSN={["0032-3861"]}, DOI={10.1016/S0032-3861(01)00689-9}, abstractNote={Ternary blends of polypropylene (PP), nylon 6 (N6) and polypropylene grafted with maleic anhydride (PP/N6/PP-g-MAH) as compatibilizer with up to 50 wt% of N6 were investigated. PP-g-MAH content was varied from 2.5 to 10%. Blends of the two polymers PP/N6 (80/20) without the compatibilizer were also prepared using an internal batch mixer and studied. The ternary blends showed different rheological properties at low and high shear rates. The difference depended on the amount of N6 dispersed phase. Co-continuous morphology was observed for the blend containing 50% N6. This blend also exhibited higher viscosity at low shear rate and lower viscosity at high shear rates than the value calculated by the simple rule of mixture. At higher shear rates, viscosity was lower than that given by the rule of mixture for all blend ratios. An increase in viscosity was observed in the 80/20 PP/N6 blend after the concentration of the interfacial agent (PP-g-MAH) was increased. Polyblends containing up to 30% N6 could be successfully melt spun into fibers. DSC results showed that dispersed and matrix phases in the fiber maintained crystallinity comparable to or better than the corresponding values found in the neat fibers. The dispersed phase was found to contain fibrils. By using SEM and LSCM analyses we were able to show that the N6 droplets coalesced during melt spinning which led to the development of fibrillar morphology.}, number={4}, journal={POLYMER}, author={Afshari, M and Kotek, R and Kish, MH and Dast, HN and Gupta, BS}, year={2002}, month={Feb}, pages={1331–1341} }