The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
K. V. S. N. Raju - One of the best experts on this subject based on the ideXlab platform.
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synthesis and characterization of hyperbranched Polyester Urethane urea k10 clay hybrid coatings
Progress in Organic Coatings, 2009Co-Authors: Aswini K. Mishra, Kishore K. Jena, K. V. S. N. RajuAbstract:A series of hyperbranched Polyester–Urethane–urea/K10-clay hybrid coatings (AHBPE-1 and AHBPE-2) have been prepared. Initially, the Polyester polyols are synthesized separately in a step-wise manner using pentaerythritol (PE), phtallic anhydride (PTA) and trimethylol propane (TMP). The cetyltrimethylammonium bromide (CTAB) modified K10-clay is used as an organoclay for the hybrid composites preparation and dispersed into the Polyester matrix by ultrasonication method. This clay-dispersed polyols are used for further synthesis. The degree of branching (DB), percentage of condensation reaction and quantity of dendritic (D), terminal (T) and linear (L) units present in the Polyester are calculated, from the NMR peak integration value. The NMR result suggests that, there is formation of nearly 63% of condensation product in the Polyester. A structure–property correlation is established, based on the hydrogen bonding effect with increasing clay content by using the FT-IR peak deconvulation technique. The dynamic mechanical and thermal analysis (DMTA) as well as thermo gravimetric analysis (TGA) results show, an increase in room temperature storage modulus (E′), glass transition temperature (Tg) and thermal stability of the hybrid coatings with increasing clay content and NCO/OH ratio. The contact angle measurement study suggests that, the hydrophilicity of the hybrid films increases with increasing clay content and decreases with increasing NCO/OH ratio.
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Synthesis and characterization of hyperbranched Polyester–Urethane–urea/K10-clay hybrid coatings
Progress in Organic Coatings, 2008Co-Authors: Aswini K. Mishra, Kishore K. Jena, K. V. S. N. RajuAbstract:A series of hyperbranched Polyester–Urethane–urea/K10-clay hybrid coatings (AHBPE-1 and AHBPE-2) have been prepared. Initially, the Polyester polyols are synthesized separately in a step-wise manner using pentaerythritol (PE), phtallic anhydride (PTA) and trimethylol propane (TMP). The cetyltrimethylammonium bromide (CTAB) modified K10-clay is used as an organoclay for the hybrid composites preparation and dispersed into the Polyester matrix by ultrasonication method. This clay-dispersed polyols are used for further synthesis. The degree of branching (DB), percentage of condensation reaction and quantity of dendritic (D), terminal (T) and linear (L) units present in the Polyester are calculated, from the NMR peak integration value. The NMR result suggests that, there is formation of nearly 63% of condensation product in the Polyester. A structure–property correlation is established, based on the hydrogen bonding effect with increasing clay content by using the FT-IR peak deconvulation technique. The dynamic mechanical and thermal analysis (DMTA) as well as thermo gravimetric analysis (TGA) results show, an increase in room temperature storage modulus (E′), glass transition temperature (Tg) and thermal stability of the hybrid coatings with increasing clay content and NCO/OH ratio. The contact angle measurement study suggests that, the hydrophilicity of the hybrid films increases with increasing clay content and decreases with increasing NCO/OH ratio.
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Degradation profiles of Polyester–Urethane (hydroxylated Polyester/diphenylmethane diisocyanate) and Polyester–melamine (hydroxylated Polyester/hexamethoxymethylmelamine) coatings: An accelerated weathering study
Journal of Applied Polymer Science, 2005Co-Authors: Ramanuj Narayan, K. V. S. N. Raju, D. K. Chattopadhyay, Bojja Sreedhar, N. N. Mallikarjuna, Tejraj M. AminabhaviAbstract:The successful material performance of coatings depends on the environmental conditions to which they are exposed. The effects of the diol structure and acetoacetylation on the weathering degradation of hydroxylated Polyester (HP)/hexamethoxymethylmelamine and HP/diphenylmethane diisocyanate clear coatings were studied. The acetoacetylation of HPs led to better performance for higher application solids than the acetoacetylation of their base counterparts. Weathering degradation profiles were investigated with dynamic mechanical thermal analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. The structural variations of the building blocks and acetoacetylation were found to be important for enhancing the stability of coatings at higher application solids. Polyester–Urethane coatings were more stable toward weathering than Polyester–melamine coatings. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1069–1081, 2005
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degradation profiles of Polyester Urethane hydroxylated Polyester diphenylmethane diisocyanate and Polyester melamine hydroxylated Polyester hexamethoxymethylmelamine coatings an accelerated weathering study
Journal of Applied Polymer Science, 2005Co-Authors: Ramanuj Narayan, K. V. S. N. Raju, D. K. Chattopadhyay, Bojja Sreedhar, N. N. Mallikarjuna, Tejraj M. AminabhaviAbstract:The successful material performance of coatings depends on the environmental conditions to which they are exposed. The effects of the diol structure and acetoacetylation on the weathering degradation of hydroxylated Polyester (HP)/hexamethoxymethylmelamine and HP/diphenylmethane diisocyanate clear coatings were studied. The acetoacetylation of HPs led to better performance for higher application solids than the acetoacetylation of their base counterparts. Weathering degradation profiles were investigated with dynamic mechanical thermal analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. The structural variations of the building blocks and acetoacetylation were found to be important for enhancing the stability of coatings at higher application solids. Polyester–Urethane coatings were more stable toward weathering than Polyester–melamine coatings. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1069–1081, 2005
Sharif Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Soy Polyester Urethane/TiO2 and Ce-TiO2 nanocomposites: preparation, characterization and evaluation of electrochemical corrosion resistance performance
RSC Advances, 2016Co-Authors: Obaid Ur Rahman, Sharif AhmadAbstract:Environment friendly soy Polyester Urethane nanocomposite coating materials were prepared by dispersing TiO2 and Ce-TiO2 nanoparticles in a 3-isocyanatopropyltriethoxysilane (IPTES) modified soy oil (SO) Polyester Urethane triethoxysilane (PEUTES) matrix via a sonication technique. Fourier Transform Infrared Spectroscopy (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), UV-visible spectroscopy (UV) were employed to characterize the synthesized coating materials. The anticorrosion ability of nanocomposites and that of PEUTES coatings on carbon steel (CS) in 3.5 wt% NaCl solution was investigated using potentiodynamic polarization (PDP), Electrochemical Impedance Spectroscopy (EIS) techniques and a salt mist test. The effects of dispersion of nano TiO2 and Ce-TiO2 fillers in PEUTES matrices on the hydrophobic, physico-mechanical, thermal and anticorrosive properties were also studied. The TiO2 and Ce-TiO2 nanofiller dispersed soy Polyester Urethane nanocomposite coatings have exhibited far superior corrosion resistance properties than those of other such reported systems. These studies revealed the presence of nanofiller in Polyester Urethane matrix, induces strong barrier and locking effects at the coating–metal interface. The higher impedance value (≈108 Ω) and lower corrosion rate (7.8518 × 10−6 mpy) confirm the superior protection ability of the nanocomposite.
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soy Polyester Urethane tio2 and ce tio2 nanocomposites preparation characterization and evaluation of electrochemical corrosion resistance performance
RSC Advances, 2016Co-Authors: Obaid Ur Rahman, Sharif AhmadAbstract:Environment friendly soy Polyester Urethane nanocomposite coating materials were prepared by dispersing TiO2 and Ce-TiO2 nanoparticles in a 3-isocyanatopropyltriethoxysilane (IPTES) modified soy oil (SO) Polyester Urethane triethoxysilane (PEUTES) matrix via a sonication technique. Fourier Transform Infrared Spectroscopy (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), UV-visible spectroscopy (UV) were employed to characterize the synthesized coating materials. The anticorrosion ability of nanocomposites and that of PEUTES coatings on carbon steel (CS) in 3.5 wt% NaCl solution was investigated using potentiodynamic polarization (PDP), Electrochemical Impedance Spectroscopy (EIS) techniques and a salt mist test. The effects of dispersion of nano TiO2 and Ce-TiO2 fillers in PEUTES matrices on the hydrophobic, physico-mechanical, thermal and anticorrosive properties were also studied. The TiO2 and Ce-TiO2 nanofiller dispersed soy Polyester Urethane nanocomposite coatings have exhibited far superior corrosion resistance properties than those of other such reported systems. These studies revealed the presence of nanofiller in Polyester Urethane matrix, induces strong barrier and locking effects at the coating–metal interface. The higher impedance value (≈108 Ω) and lower corrosion rate (7.8518 × 10−6 mpy) confirm the superior protection ability of the nanocomposite.
Thomas Franz - One of the best experts on this subject based on the ideXlab platform.
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Electrospun Polyester-Urethane scaffold preserves mechanical properties and exhibits strain stiffening during in situ tissue ingrowth and degradation
SN Applied Sciences, 2020Co-Authors: Hugo Krynauw, Rodaina Omar, Josepha Koehne, Georges Limbert, Neil Hamer Davies, Deon Bezuidenhout, Thomas FranzAbstract:Consistent mechanical performance from implantation through healing and scaffold degradation is highly desired for tissue-regenerative scaffolds, e.g. when used for vascular grafts. The aim of this study was the paired in vivo mechanical assessment of biostable and fast degrading electrospun Polyester-Urethane scaffolds to isolate the effects of material degradation and tissue formation after implantation. Biostable and degradable Polyester-Urethane scaffolds with substantial fibre alignment were manufactured by electrospinning. Scaffold samples were implanted paired in subcutaneous position in rats for 7, 14 and 28 days. Morphology, mechanical properties and tissue ingrowth of the scaffolds were assessed before implantation and after retrieval. Tissue ingrowth after 28 days was 83 ± 10% in the biostable scaffold and 77 ± 4% in the degradable scaffold. For the biostable scaffold, the elastic modulus at 12% strain increased significantly between 7 and 14 days and decreased significantly thereafter in fibre but not in cross-fibre direction. The degradable scaffold exhibited a significant increase in the elastic modulus at 12% strain from 7 to 14 days after which it did not decrease but remained at the same magnitude, both in fibre and in cross-fibre direction. Considering that the degradable scaffold loses its material strength predominantly during the first 14 days of hydrolytic degradation (as observed in our previous in vitro study), the consistency of the elastic modulus of the degradable scaffold after 14 days is an indication that the regenerated tissue construct retains its mechanical properties.
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Data: Electrospun Polyester-Urethane scaffold preserves mechanical properties and exhibits strain stiffening during in situ tissue ingrowth and degradation
2019Co-Authors: Rodaina Omar, Josepha Koehne, Hugo Krynauw, Georges Limbert, Neil Hamer Davies, Deon Bezuidenhout, Thomas FranzAbstract:The provided material represents the data for fibre diameter, fibre alignment, tissue ingrowth and mechanical properties of an tissue-engineering electrospun polymeric scaffold related to the article Krynauw H, Omar R, Koehne J, Limbert G, Davies NH, Bezuidenhout D, Franz T, Electrospun Polyester-Urethane scaffold preserves mechanical properties and exhibits strain stiffening during in situ tissue ingrowth and degradation. bioRxiv, 2019: 783522
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Constitutive Effects of Hydrolytic Degradation in Electro-Spun Polyester-Urethane Scaffolds for Soft Tissue Regeneration
Tissue Engineering, 2014Co-Authors: Hugo Krynauw, Deon Bezuidenhout, Lucie Bruchmüller, Peter Zilla, Thomas FranzAbstract:In tissue regenerative implants, porosity allowing the ingrowth of cells and tissue is a key factor for the long-term success. While vital for healing and tissue regeneration, the use of highly porous structures may adversely affect the mechanical properties of the scaffold, in particular when viscoelastic polymeric materials are used. In the case of biodegradable scaffold materials, the effect of the degradation process on mechanical and structural properties of the scaffold is yet another aspect to be considered. Both tissue ingrowth and biodegradation are concurrent transient processes which change the mechanical and structural properties of the implanted device over time. Ingrowth of cells and tissue typically results in an increase in structural stiffness whereas scaffold degradation leads to loss of mechanical properties and potentially to structural disintegration. The aim of the research presented in this chapter was the investigation of the change of mechanical properties of a biodegradable, electro-spun Polyester-Urethane scaffold for soft tissue regeneration during hydrolytic degradation and the development of a constitutive model that is suitable for capturing these changes.
Aswini K. Mishra - One of the best experts on this subject based on the ideXlab platform.
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synthesis and characterization of hyperbranched Polyester Urethane urea k10 clay hybrid coatings
Progress in Organic Coatings, 2009Co-Authors: Aswini K. Mishra, Kishore K. Jena, K. V. S. N. RajuAbstract:A series of hyperbranched Polyester–Urethane–urea/K10-clay hybrid coatings (AHBPE-1 and AHBPE-2) have been prepared. Initially, the Polyester polyols are synthesized separately in a step-wise manner using pentaerythritol (PE), phtallic anhydride (PTA) and trimethylol propane (TMP). The cetyltrimethylammonium bromide (CTAB) modified K10-clay is used as an organoclay for the hybrid composites preparation and dispersed into the Polyester matrix by ultrasonication method. This clay-dispersed polyols are used for further synthesis. The degree of branching (DB), percentage of condensation reaction and quantity of dendritic (D), terminal (T) and linear (L) units present in the Polyester are calculated, from the NMR peak integration value. The NMR result suggests that, there is formation of nearly 63% of condensation product in the Polyester. A structure–property correlation is established, based on the hydrogen bonding effect with increasing clay content by using the FT-IR peak deconvulation technique. The dynamic mechanical and thermal analysis (DMTA) as well as thermo gravimetric analysis (TGA) results show, an increase in room temperature storage modulus (E′), glass transition temperature (Tg) and thermal stability of the hybrid coatings with increasing clay content and NCO/OH ratio. The contact angle measurement study suggests that, the hydrophilicity of the hybrid films increases with increasing clay content and decreases with increasing NCO/OH ratio.
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Synthesis and characterization of hyperbranched Polyester–Urethane–urea/K10-clay hybrid coatings
Progress in Organic Coatings, 2008Co-Authors: Aswini K. Mishra, Kishore K. Jena, K. V. S. N. RajuAbstract:A series of hyperbranched Polyester–Urethane–urea/K10-clay hybrid coatings (AHBPE-1 and AHBPE-2) have been prepared. Initially, the Polyester polyols are synthesized separately in a step-wise manner using pentaerythritol (PE), phtallic anhydride (PTA) and trimethylol propane (TMP). The cetyltrimethylammonium bromide (CTAB) modified K10-clay is used as an organoclay for the hybrid composites preparation and dispersed into the Polyester matrix by ultrasonication method. This clay-dispersed polyols are used for further synthesis. The degree of branching (DB), percentage of condensation reaction and quantity of dendritic (D), terminal (T) and linear (L) units present in the Polyester are calculated, from the NMR peak integration value. The NMR result suggests that, there is formation of nearly 63% of condensation product in the Polyester. A structure–property correlation is established, based on the hydrogen bonding effect with increasing clay content by using the FT-IR peak deconvulation technique. The dynamic mechanical and thermal analysis (DMTA) as well as thermo gravimetric analysis (TGA) results show, an increase in room temperature storage modulus (E′), glass transition temperature (Tg) and thermal stability of the hybrid coatings with increasing clay content and NCO/OH ratio. The contact angle measurement study suggests that, the hydrophilicity of the hybrid films increases with increasing clay content and decreases with increasing NCO/OH ratio.
Obaid Ur Rahman - One of the best experts on this subject based on the ideXlab platform.
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Soy Polyester Urethane/TiO2 and Ce-TiO2 nanocomposites: preparation, characterization and evaluation of electrochemical corrosion resistance performance
RSC Advances, 2016Co-Authors: Obaid Ur Rahman, Sharif AhmadAbstract:Environment friendly soy Polyester Urethane nanocomposite coating materials were prepared by dispersing TiO2 and Ce-TiO2 nanoparticles in a 3-isocyanatopropyltriethoxysilane (IPTES) modified soy oil (SO) Polyester Urethane triethoxysilane (PEUTES) matrix via a sonication technique. Fourier Transform Infrared Spectroscopy (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), UV-visible spectroscopy (UV) were employed to characterize the synthesized coating materials. The anticorrosion ability of nanocomposites and that of PEUTES coatings on carbon steel (CS) in 3.5 wt% NaCl solution was investigated using potentiodynamic polarization (PDP), Electrochemical Impedance Spectroscopy (EIS) techniques and a salt mist test. The effects of dispersion of nano TiO2 and Ce-TiO2 fillers in PEUTES matrices on the hydrophobic, physico-mechanical, thermal and anticorrosive properties were also studied. The TiO2 and Ce-TiO2 nanofiller dispersed soy Polyester Urethane nanocomposite coatings have exhibited far superior corrosion resistance properties than those of other such reported systems. These studies revealed the presence of nanofiller in Polyester Urethane matrix, induces strong barrier and locking effects at the coating–metal interface. The higher impedance value (≈108 Ω) and lower corrosion rate (7.8518 × 10−6 mpy) confirm the superior protection ability of the nanocomposite.
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soy Polyester Urethane tio2 and ce tio2 nanocomposites preparation characterization and evaluation of electrochemical corrosion resistance performance
RSC Advances, 2016Co-Authors: Obaid Ur Rahman, Sharif AhmadAbstract:Environment friendly soy Polyester Urethane nanocomposite coating materials were prepared by dispersing TiO2 and Ce-TiO2 nanoparticles in a 3-isocyanatopropyltriethoxysilane (IPTES) modified soy oil (SO) Polyester Urethane triethoxysilane (PEUTES) matrix via a sonication technique. Fourier Transform Infrared Spectroscopy (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), UV-visible spectroscopy (UV) were employed to characterize the synthesized coating materials. The anticorrosion ability of nanocomposites and that of PEUTES coatings on carbon steel (CS) in 3.5 wt% NaCl solution was investigated using potentiodynamic polarization (PDP), Electrochemical Impedance Spectroscopy (EIS) techniques and a salt mist test. The effects of dispersion of nano TiO2 and Ce-TiO2 fillers in PEUTES matrices on the hydrophobic, physico-mechanical, thermal and anticorrosive properties were also studied. The TiO2 and Ce-TiO2 nanofiller dispersed soy Polyester Urethane nanocomposite coatings have exhibited far superior corrosion resistance properties than those of other such reported systems. These studies revealed the presence of nanofiller in Polyester Urethane matrix, induces strong barrier and locking effects at the coating–metal interface. The higher impedance value (≈108 Ω) and lower corrosion rate (7.8518 × 10−6 mpy) confirm the superior protection ability of the nanocomposite.