| 1. |
- Amer, Wael A., et al.
(författare)
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Liquid-crystalline azobenzene-containing ferrocene-based polymers : study on synthesis and properties of main-chain ferrocene-based polyesters with azobenzene in the side chain
- 2013
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Ingår i: Polymers for Advanced Technologies. - : Wiley. - 1042-7147 .- 1099-1581. ; 24:2, s. 181-190
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Tidskriftsartikel (refereegranskat)abstract
- Ferrocene-based polymers are characterized by their electrochemical activity, good redox properties, thermal, photochemical stability, and liquid crystallinity, and thus they have various applications in different fields. A comprehensive investigation on the synthesis and properties of three novel main-chain ferrocene-based polyesters with azobenzene in the side chain (MFPAS) was carried out. The main-chain ferrocene-based polyester, poly(N-phenyldiethanolamine 1,1'-ferrocene dicarboxylate (PPFD), was synthesized via the solution polycondensation reaction of 1,1'-ferrocenedicarbonyl chloride with phenyldiethanolamine (PDE). The novel MFPAS were synthesized via the post-polymerization azo-coupling reaction of PPFD with three different 4-substituted anilines including 4-nitroaniline, 4-aminobenzoic acid, and 4-aminobenzonitrile to produce 4-nitrophenylazo-functionalized-PPFD (PPFD-NT), 4-carboxyphenylazo-functionalized-PPFD (PPFD-CA), and 4-cyanophenylazo-functionalized-PPFD (PPFD-CN), respectively. All the synthesized polymers were characterized by 1H NMR spectroscopy, Fourier transform infrared spectroscopy, and UVvisible spectroscopy. In addition, powder X-ray diffraction patterns were measured for the synthesized polymers. The photoisomerization of the MFPAS was studied. The thermal properties of the MFPAS were studied using thermogravimetric analysis and differential scanning calorimetry. PPFD-CA and PPFD-CN were found to be more thermally stable than PPFD-NT. Finally, the liquid-crystalline properties of PPFD and the MFPAS were examined using polarized optical microscope. It was found that all the polymers possessed nematic phases and exhibited textures with schlieren disclinations.
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| 2. |
- Anass, Benayad, et al.
(författare)
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Simulation of crystallization evolution of polyoxymethylene during microinjection molding cycle
- 2020
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Ingår i: Polymers for Advanced Technologies. - : Wiley. - 1042-7147 .- 1099-1581. ; 31:4, s. 838-852
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model coupled with a numerical investigation of the evolving material properties due to thermal and flow effects and in particular the evolution of the crystallinity during the full microinjection molding cycle of poly (oxymethylene) POM is presented using a multi-scale approach. A parametric analysis is performed, including all the steps of the process using an asymmetrical stepped contracting part. The velocity and temperature fields are discussed. A parabolic distribution of the velocity across the part thickness, and a temperature rise in the thin zone toward the wall have been obtained. It is attributed to the viscous energy dissipation during the filling phase, but also to the involved characteristic times for the thermal behavior of the material. Depending on the molding conditions and the locations within the micro-part, different evolution of crystallization rates are obtained leading to at least three to five morphological layers, obtained in the same part configuration of a previously work, allowing a clear understanding of the process-material interaction.
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| 3. |
- Bashir, Tariq, 1981-, et al.
(författare)
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High-strength electrically conductive fibers: functionalization of polyamide, aramid and polyester fibers with PEDOT polymer
- 2017
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Ingår i: Polymers for Advanced Technologies. - : John Wiley & Sons. - 1042-7147 .- 1099-1581. ; 29:1, s. 310-318
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Tidskriftsartikel (refereegranskat)abstract
- In this work, high-performance fibers such as aramid (Twaron), polyamide (PA6), polyester (PET), and hybrid Twaron/PA6 fibers were transformed into electroactive fibers by coating them with conjugated polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) through vapor phase polymerization (VPP) method. The VPP is considered as an efficient technique for depositing CPs on different substrates regardless of their lower solubility in various solvents. In this paper, PEDOT-coated high-performance fibers were prepared under already optimized reaction conditions, and then a comparison between electrical, thermal, and mechanical properties of different fibers, before and after coating, was made. The obtained coated fibers were characterized through scanning electron microscope (SEM), thermogravimetric analysis (TGA), 2-probe electrical resistance measurement method, and tensile testing. It was revealed that at particular reaction conditions, all high performance textile substrates were successfully converted into electroactive fibers. The voltage-current (V-I) characteristics showed that PEDOT-coated polyester fibers exhibited highest conductivity value among all other substrate fibers. The active PEDOT layers on high performance fibers could behave as an antistatic coating to minimize the risks associated with static charges at work places. Also, the obtained fibers have potential to be used as smart materials for various medical, sports, and military applications.
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| 4. |
- Bashir, Tariq, et al.
(författare)
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OCVD polymerization of PEDOT : effect of pre-treatment steps on PEDOT-coated conductive fibers and a morphological study of PEDOT distribution on textile yarns
- 2013
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Ingår i: Polymers for Advanced Technologies. - : John Wiley & Sons. - 1042-7147 .- 1099-1581. ; 24:2, s. 210-219
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Tidskriftsartikel (refereegranskat)abstract
- The functionalization of textile fibers with intrinsically conductive polymers has become a prominent research area throughout the world. A number of coating techniques have already been utilized and optimized to get the uniform layers of conductive polymers on the surface of different substrates. In our previous study, we produced poly(3,4-ethylenedioxythiophene) (PEDOT)-coated conductive fibers by employing oxidative chemical vapor deposition (oCVD) technique. This paper describes the effects of pre-treatment steps, such as surface treatment of textile fibers with organic solvents, drying of oxidant-enriched fibers at variable temperatures and time, and oxidant type on the electrical, mechanical, and thermal properties of PEDOT-coated conductive fibers. Two well-known oxidants, ferric(III)chloride and ferric(III)p-toluenesulfonate (FepTS), were studied, and then their results were compared. In order to verify the PEDOT-coated layer and, to some extent, its impregnation inside the viscose yarns, a morphological study was carried out by using the attenuated total reflectance Fourier transform infrared spectroscopic imaging technique and computed tomography scanning across the obtained conductive fibers. Differential scanning calorimetric and thermogravimetric analysis were utilized to investigate the thermal properties and the contents of PEDOT in PEDOT-coated fibers. The mechanical properties of conductive fibers were evaluated by tensile strength testing of produced fibers. Effects of all of these pre-treatment steps on electrical properties were analyzed with Kiethly picoammeter. This study cannot only be exploited to improve the properties of conductive fibers but also to optimize the oCVD process for the production of conductive textile fibers by coating with different conjugated polymers.
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| 5. |
- Bashir, Tariq, et al.
(författare)
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Production of Highly Conductive Textile Viscose Yarns by Chemical Vapor Deposition Technique : A Route to Continuous Process
- 2010
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Ingår i: Polymers for Advanced Technologies. - : Wiley. - 1042-7147 .- 1099-1581. ; 22:12, s. 2214-2221
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Tidskriftsartikel (refereegranskat)abstract
- An oxidative chemical vapor deposition (OCVD) process was used to coat flexible textile fiber (viscose) with highly conductive polymer, poly (3,4-ethylenedioxythiophene) (PEDOT) in resence of ferric (III) chloride (FeCl3) oxidant. OCVD is a solvent free process used to get uniform, thin, and highly conductive polymer layer on different substrates. In this paper, PEDOT coated viscose fibers, prepared under specific conditions, exhibited high conductivity 14.2 S/cm. The effects of polymerization conditions, such as polymerization time, oxidant concentration, dipping time of viscose fiber in oxidant solution, and drying time of oxidant treated viscose fiber, were carefully investigated. Scanning electron microscopy (SEM) and FT-IR analysis revealed that polymerization of PEDOT on surface of viscose fiber has been taken place and structural analysis showed strong interactions between PEDOT and viscose fiber. Thermogravimetric analysis (TGA) was employed to investigate the amount of PEDOT in PEDOT coated viscose fiber and interaction of PEDOT with viscose fiber. The effect of PEDOT coating on the mechanical properties of the viscose fiber was evaluated by tensile strength testing of the coated fibers. The obtained PEDOT coated viscose fiber having high conductivity, could be used in smart clothing for medical and military applications, heat generation, and solar cell demonstrators.
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| 6. |
- Bashir, Tariq, et al.
(författare)
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Synthesis of electro-active membranes by chemical vapor deposition (CVD) process
- 2014
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Ingår i: Polymers for Advanced Technologies. - : John Wiley & Sons, Ltd.. - 1042-7147 .- 1099-1581. ; 25:12, s. 1501-1508
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Tidskriftsartikel (refereegranskat)abstract
- In the past two decades, many research is being carried out on coating of textile membranes with conductive polymers. In order to functionalize the textile membranes, coating of different intrinsically conductive polymers can be applied on these membranes through appropriate coating techniques like electrochemical polymerization, wet chemical oxidation and chemical vapor deposition(CVD. Noticeably, CVD process is one of the most suitable and environment friendly technique. In this research, microporous polyester and polytetrafluoroethylene (PTFE) membranes were coated with conductive poly(3,4-ethylenedioxythiophene) (PEDOT) by CVD process in the presence of ferric(III)chloride (FeCl3) used as an oxidant. Polymerization of PEDOT on the surface of membranes and pore size was examined by optical microscope and scanning electron microscopy (SEM). Structural analysis investigated with ATR-FTIR, which revealed the successful deposition of PEDOT on membranes without damaging their parent structures. The amount of PEDOT in PEDOT-coated polyester and PTFE membranes was explored with the help of thermogravimeteric analysis. Electrical resistance values of PEDOT-coated membranes were measured by two probe method. The effect of different electrolyte solutions such as, distilled H2O, Na2SO4, HCl, and H2SO4 on electrical properties of produced conductive membranes was investigated after dipping for certain period of time. It was found that membranes dipped in H2SO4 show very low electrical resistance values, i.e. 0.85 kΩ for polyester membrane and 1.17 kΩ for PTFE membrane. The obtained PEDOT-coated electro-active membranes may find their possible utility in fuel cells, enzymatic fuel cells, and antistatic air filter applications.
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| 7. |
- Bashir, Tariq, et al.
(författare)
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Synthesis of High Performance, Conductive PEDOT-coated Polyester Yarns by OCVD Technique
- 2012
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Ingår i: Polymers for Advanced Technologies. - : John Wiley & Sons. - 1042-7147 .- 1099-1581. ; 23:3, s. 611-617
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Tidskriftsartikel (refereegranskat)abstract
- Production of high performance conductive textile yarn fibers for different electronic applications has become a prominent area of many research groups throughout the world. We have used oxidative chemical vapor deposition (OCVD) technique to coat flexible and high strength polyester yarns with conjugated polymer, poly(3,4- ethylenedioxythiophene) (PEDOT) in presence of ferric (III) chloride (FeCl3) oxidant. OCVD is an efficient solvent free technique used to get uniform, thin, and highly conductive polymer layers on different substrates. In this paper, PEDOT-coated polyester (PET) yarns were prepared under specific reaction conditions, and the electrical, mechanical and thermal properties were compared to previously studied PEDOT-coated viscose yarns. Scanning electron microscopy (SEM) and FT-IR analysis revealed that polymerization of PEDOT on the surface of the polyester yarns has been taken place successfully and structural analysis showed that PEDOT has strong interactions with viscose yarns as compared to PET yarns. The voltage–current (V–I) characteristics showed that PET yarns are more conductive than PEDOT-coated viscose yarns. The variation in the conductivity of PEDOT-coated yarns and the heat generation properties during the flow of current through coated yarns for longer period of time, was studied by time–current (t–I) characteristics. Thermogravimeteric analysis (TGA) was employed to investigate the thermal properties and the amount of PEDOT in PEDOT-coated PET yarns compared to PEDOT-coated viscose. The effect of PEDOT coating and ferric (III) chloride concentration on the mechanical properties of coated yarns was evaluated by tensile testing. The obtained PEDOT-coated conductive polyester yarns could be used in smart clothing for medical and military applications.
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| 8. |
- Edlund, Ulrica, et al.
(författare)
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Covalent VEGF protein immobilization on resorbable polymeric surfaces
- 2011
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Ingår i: Polymers for Advanced Technologies. - : Wiley. - 1042-7147 .- 1099-1581. ; 22:12, s. 2368-2373
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor type protein (VEGF), a potent angiogenic effector molecule, was successfully covalently immobilized onto the surfaces of the resorbable polymers poly(L-lactic acid) (PLLA) and poly(epsilon-caprolactone) (PCL) through a three-step strategy. The surfaces were first covalently grafted with poly(acrylic acid) using non-destructive and solvent free vapor-phase grafting. A diamine spacer was coupled to the carboxylic acid pendant groups on the graft chains using EDC/NHS chemistry and VEGF was finally covalently attached to the amine linkers. The chemistry and topography of the modified substrates were quantitatively and qualitatively verified with XPS, ATR-FTIR, UV-VIS, SEM, and ELISA.
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| 9. |
- Edlund, Ulrica, 1972-, et al.
(författare)
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Covalent VEGF protein immobilization on resorbable polymeric surfaces
- 2011
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Ingår i: Polymers for Advanced Technologies. - : Wiley. - 1042-7147 .- 1099-1581. ; 22:1, s. 166-171
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor (VEGF) type protein, a potent angiogenic effector molecule, was successfully covalently immobilized onto the surfaces of the resorbable polymers poly(L-lactic acid) (PLLA) and poly(epsilon-caprolactone) through a three-step strategy. The surfaces were first covalently grafted with poly(acrylic acid) using non-destructive and solvent-free vapor-phase grafting. A diamine spacer was coupled to the carboxylic acid pendant groups on the graft chains using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride/N-hydroxysuccinimide chemistry and VEGF was finally covalently attached to the amine linkers. The chemistry and topography of the modified substrates were quantitatively and qualitatively verified with X-ray photoelectron spectroscopy, attenuated total reflectance-Fourier transform infrared spectrometry, UV-VIS, scanning electron microscopy, and enzyme-linked immunosorbent assay
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| 10. |
- Edwin Samson, Ponnusamy, et al.
(författare)
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The effect of fiber orientation and stacking sequence on carbon/E-glass/epoxy intraply hybrid composites under dynamic loading conditions
- 2023
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Ingår i: Polymers for Advanced Technologies. - : John Wiley and Sons Ltd. - 1042-7147 .- 1099-1581. ; 34:1, s. 363-376
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the dynamic mechanical properties of hybrid intraply carbon/E-glass epoxy composites with different orientations and stacking sequences under different loading conditions with increasing temperature. A neat epoxy and five various hybrid composites such as Carbon (0°)/E-glass (90°), Carbon (45°)/E-glass (135°), Carbon (90°)/E-glass (0°), Carbon/E-glass (alternating layer), and Carbon/E-glass (alternating layer 45°) were manufactured. Three-point bending test and dynamic mechanical test were conducted to understand the flexural modulus and viscoelastic behavior (storage modulus, loss modulus, and loss tangent) of the composites. Dynamic mechanical test was performed with the dual cantilever method, at four different frequencies (1, 5, 10, and 20 Hz) and temperatures ranging from 30 to 150°C. The experimental results of storage modulus, loss modulus, and loss tangents were compared with the theoretical findings of neat epoxy and various hybrid composites. The glass transition temperature (Tg) increased with the increase in frequency. A linear fit of the natural log of frequency to the inverse of absolute temperature was plotted in the activation energy estimation. The interphase damping (tanδi) between plies and the strength indicator (Si) of the hybrid composites were estimated. It was observed that the neat epoxy had more insufficient storage and loss modulus and a high loss tangent at all the frequencies whereas hybrid composites had high storage and loss modulus and a low loss tangent for all the frequencies. Compared with other hybrid composites, Carbon (90°)/E-glass (0°) had higher strength and activation energy. The result of reinforcement of hybrid fiber in neat epoxy significantly increases the material's strength and stability at higher temperatures whereas decreasing free molecular movement.
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