The Experts below are selected from a list of 2085 Experts worldwide ranked by ideXlab platform
Hongsheng Luo - One of the best experts on this subject based on the ideXlab platform.
-
path dependent and selective multi shape recovery of a polyurethane Cellulose Whisker nanocomposite
Materials Letters, 2012Co-Authors: Hongsheng Luo, Yong ZhuAbstract:Abstract Incorporation of Cellulose nano-Whiskers (CNWs) into shape memory polyurethane (SMPU) endowed the composites with thermo- and water-sensitive triple switches. The thermal transitions of the composites were measured by Differential Scanning Calorimetry (DSC). Path-dependent and selective multi-shape recovery was unprecedentedly achieved for the single CNW–SMPU nanocomposite, as determined by elaborately designed tensile tests. The composite offered five paths of shape recovery with choices of dual, triple and quadruple shapes using only one-step programming. Photographs recording the quadruple-shape recovery of the composite along water and heat stimulations were presented. This high level of adaptability of the composite may be beneficial for developing novel functional polymeric composites.
-
morphology reversible phase crystallization and thermal sensitive shape memory effect of Cellulose Whisker smpu nano composites
Journal of Applied Polymer Science, 2012Co-Authors: Jianping Han, Yong Zhu, Hongsheng Luo, Lap-yan Yeung, Qinghao Meng, Sheng Zhang, Ying FanAbstract:To investigate the morphology, crystallization properties of reversible phase and thermal sensitive shape memory properties of CW/SMPU (Cellulose Whisker/Shape Memory Polyurethane) nano-composite, the CW/SMPU nano-composite having CW contents of 0.1–3.8 wt % were prepared. SEM investigation showed the evolution of reversible phase morphology from spherolite crystallization structure to uniform matrix with tiny CW aggregates with the addition of CW into the SMPU matrix. DSC and isothermal crystallization kinetic method revealed the effect of CW on crystallization properties of reversible phase and fixed phase, suggesting that the effect of CW on the crystallization of hard segment phase is not comparable with thermal history; the more CW causes the higher crystallization rate of reversible phase; the crystallization mechanism of reversible phase in nano-composite gradually evolves to heterogeneous nucleation and crystal growth in two dimensions with the increase of CW content; the excellent nucleation effect of CW for the reversible phase leads to the drop of activity energy from 134.1 kJ/mol (N-0), to 95.1 kJ/mol (N-4). Cyclic tensile tests illustrate the addition of CW content can engender rapid shape fixity ability after a relative short cooling time; the shape fixity ratio of nano-composite and the control sample after sufficient cooling all can be identically high. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
-
Path-dependent and selective multi-shape recovery of a polyurethane/Cellulose-Whisker nanocomposite
Materials Letters, 2012Co-Authors: Hongsheng Luo, Yong ZhuAbstract:Abstract Incorporation of Cellulose nano-Whiskers (CNWs) into shape memory polyurethane (SMPU) endowed the composites with thermo- and water-sensitive triple switches. The thermal transitions of the composites were measured by Differential Scanning Calorimetry (DSC). Path-dependent and selective multi-shape recovery was unprecedentedly achieved for the single CNW–SMPU nanocomposite, as determined by elaborately designed tensile tests. The composite offered five paths of shape recovery with choices of dual, triple and quadruple shapes using only one-step programming. Photographs recording the quadruple-shape recovery of the composite along water and heat stimulations were presented. This high level of adaptability of the composite may be beneficial for developing novel functional polymeric composites.
-
Morphology, reversible phase crystallization, and thermal sensitive shape memory effect of Cellulose Whisker/SMPU nano‐composites
Journal of Applied Polymer Science, 2011Co-Authors: Jianping Han, Yong Zhu, Hongsheng Luo, Lap-yan Yeung, Qinghao Meng, Sheng Zhang, Ying FanAbstract:To investigate the morphology, crystallization properties of reversible phase and thermal sensitive shape memory properties of CW/SMPU (Cellulose Whisker/Shape Memory Polyurethane) nano-composite, the CW/SMPU nano-composite having CW contents of 0.1–3.8 wt % were prepared. SEM investigation showed the evolution of reversible phase morphology from spherolite crystallization structure to uniform matrix with tiny CW aggregates with the addition of CW into the SMPU matrix. DSC and isothermal crystallization kinetic method revealed the effect of CW on crystallization properties of reversible phase and fixed phase, suggesting that the effect of CW on the crystallization of hard segment phase is not comparable with thermal history; the more CW causes the higher crystallization rate of reversible phase; the crystallization mechanism of reversible phase in nano-composite gradually evolves to heterogeneous nucleation and crystal growth in two dimensions with the increase of CW content; the excellent nucleation effect of CW for the reversible phase leads to the drop of activity energy from 134.1 kJ/mol (N-0), to 95.1 kJ/mol (N-4). Cyclic tensile tests illustrate the addition of CW content can engender rapid shape fixity ability after a relative short cooling time; the shape fixity ratio of nano-composite and the control sample after sufficient cooling all can be identically high. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Yong Zhu - One of the best experts on this subject based on the ideXlab platform.
-
path dependent and selective multi shape recovery of a polyurethane Cellulose Whisker nanocomposite
Materials Letters, 2012Co-Authors: Hongsheng Luo, Yong ZhuAbstract:Abstract Incorporation of Cellulose nano-Whiskers (CNWs) into shape memory polyurethane (SMPU) endowed the composites with thermo- and water-sensitive triple switches. The thermal transitions of the composites were measured by Differential Scanning Calorimetry (DSC). Path-dependent and selective multi-shape recovery was unprecedentedly achieved for the single CNW–SMPU nanocomposite, as determined by elaborately designed tensile tests. The composite offered five paths of shape recovery with choices of dual, triple and quadruple shapes using only one-step programming. Photographs recording the quadruple-shape recovery of the composite along water and heat stimulations were presented. This high level of adaptability of the composite may be beneficial for developing novel functional polymeric composites.
-
morphology reversible phase crystallization and thermal sensitive shape memory effect of Cellulose Whisker smpu nano composites
Journal of Applied Polymer Science, 2012Co-Authors: Jianping Han, Yong Zhu, Hongsheng Luo, Lap-yan Yeung, Qinghao Meng, Sheng Zhang, Ying FanAbstract:To investigate the morphology, crystallization properties of reversible phase and thermal sensitive shape memory properties of CW/SMPU (Cellulose Whisker/Shape Memory Polyurethane) nano-composite, the CW/SMPU nano-composite having CW contents of 0.1–3.8 wt % were prepared. SEM investigation showed the evolution of reversible phase morphology from spherolite crystallization structure to uniform matrix with tiny CW aggregates with the addition of CW into the SMPU matrix. DSC and isothermal crystallization kinetic method revealed the effect of CW on crystallization properties of reversible phase and fixed phase, suggesting that the effect of CW on the crystallization of hard segment phase is not comparable with thermal history; the more CW causes the higher crystallization rate of reversible phase; the crystallization mechanism of reversible phase in nano-composite gradually evolves to heterogeneous nucleation and crystal growth in two dimensions with the increase of CW content; the excellent nucleation effect of CW for the reversible phase leads to the drop of activity energy from 134.1 kJ/mol (N-0), to 95.1 kJ/mol (N-4). Cyclic tensile tests illustrate the addition of CW content can engender rapid shape fixity ability after a relative short cooling time; the shape fixity ratio of nano-composite and the control sample after sufficient cooling all can be identically high. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
-
Path-dependent and selective multi-shape recovery of a polyurethane/Cellulose-Whisker nanocomposite
Materials Letters, 2012Co-Authors: Hongsheng Luo, Yong ZhuAbstract:Abstract Incorporation of Cellulose nano-Whiskers (CNWs) into shape memory polyurethane (SMPU) endowed the composites with thermo- and water-sensitive triple switches. The thermal transitions of the composites were measured by Differential Scanning Calorimetry (DSC). Path-dependent and selective multi-shape recovery was unprecedentedly achieved for the single CNW–SMPU nanocomposite, as determined by elaborately designed tensile tests. The composite offered five paths of shape recovery with choices of dual, triple and quadruple shapes using only one-step programming. Photographs recording the quadruple-shape recovery of the composite along water and heat stimulations were presented. This high level of adaptability of the composite may be beneficial for developing novel functional polymeric composites.
-
Morphology, reversible phase crystallization, and thermal sensitive shape memory effect of Cellulose Whisker/SMPU nano‐composites
Journal of Applied Polymer Science, 2011Co-Authors: Jianping Han, Yong Zhu, Hongsheng Luo, Lap-yan Yeung, Qinghao Meng, Sheng Zhang, Ying FanAbstract:To investigate the morphology, crystallization properties of reversible phase and thermal sensitive shape memory properties of CW/SMPU (Cellulose Whisker/Shape Memory Polyurethane) nano-composite, the CW/SMPU nano-composite having CW contents of 0.1–3.8 wt % were prepared. SEM investigation showed the evolution of reversible phase morphology from spherolite crystallization structure to uniform matrix with tiny CW aggregates with the addition of CW into the SMPU matrix. DSC and isothermal crystallization kinetic method revealed the effect of CW on crystallization properties of reversible phase and fixed phase, suggesting that the effect of CW on the crystallization of hard segment phase is not comparable with thermal history; the more CW causes the higher crystallization rate of reversible phase; the crystallization mechanism of reversible phase in nano-composite gradually evolves to heterogeneous nucleation and crystal growth in two dimensions with the increase of CW content; the excellent nucleation effect of CW for the reversible phase leads to the drop of activity energy from 134.1 kJ/mol (N-0), to 95.1 kJ/mol (N-4). Cyclic tensile tests illustrate the addition of CW content can engender rapid shape fixity ability after a relative short cooling time; the shape fixity ratio of nano-composite and the control sample after sufficient cooling all can be identically high. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Biqiong Chen - One of the best experts on this subject based on the ideXlab platform.
-
mechanically adaptive and shape memory behaviour of chitosan modified Cellulose Whisker elastomer composites in different ph environments
ChemPhysChem, 2014Co-Authors: Biqiong ChenAbstract:Biomimetic polymer composites with water-active mechanically adaptive and shape-memory behaviour in different pH environments are synthesised by using chitosan-modified Cellulose Whiskers (CS-CWs) as the stimulus-responsive phase and thermoplastic polyurethane (TPU) as the resilient matrix. The effect of surface modification on the mechanically adaptive behaviour of CS-CW/TPU composites is investigated by using three representative solutions with various pH values. The results show that surface modification significantly enhances the modulus contrast under wet and dry conditions with the acidic solution as the stimulus, while maintaining the high modulus contrast with the basic solution as the stimulus. CS-CW/TPU composites also exhibit excellent shape-memory effects in all three solutions that are comparable to those pristine CW/TPU composites. Furthermore, activation of force generation in the stretched CS-CW/TPU composites by water absorption/desorption was observed.
-
Mechanically Adaptive and Shape‐Memory Behaviour of Chitosan‐Modified Cellulose Whisker/Elastomer Composites in Different pH Environments
ChemPhysChem, 2014Co-Authors: Biqiong ChenAbstract:Biomimetic polymer composites with water-active mechanically adaptive and shape-memory behaviour in different pH environments are synthesised by using chitosan-modified Cellulose Whiskers (CS-CWs) as the stimulus-responsive phase and thermoplastic polyurethane (TPU) as the resilient matrix. The effect of surface modification on the mechanically adaptive behaviour of CS-CW/TPU composites is investigated by using three representative solutions with various pH values. The results show that surface modification significantly enhances the modulus contrast under wet and dry conditions with the acidic solution as the stimulus, while maintaining the high modulus contrast with the basic solution as the stimulus. CS-CW/TPU composites also exhibit excellent shape-memory effects in all three solutions that are comparable to those pristine CW/TPU composites. Furthermore, activation of force generation in the stretched CS-CW/TPU composites by water absorption/desorption was observed.
Ying Fan - One of the best experts on this subject based on the ideXlab platform.
-
morphology reversible phase crystallization and thermal sensitive shape memory effect of Cellulose Whisker smpu nano composites
Journal of Applied Polymer Science, 2012Co-Authors: Jianping Han, Yong Zhu, Hongsheng Luo, Lap-yan Yeung, Qinghao Meng, Sheng Zhang, Ying FanAbstract:To investigate the morphology, crystallization properties of reversible phase and thermal sensitive shape memory properties of CW/SMPU (Cellulose Whisker/Shape Memory Polyurethane) nano-composite, the CW/SMPU nano-composite having CW contents of 0.1–3.8 wt % were prepared. SEM investigation showed the evolution of reversible phase morphology from spherolite crystallization structure to uniform matrix with tiny CW aggregates with the addition of CW into the SMPU matrix. DSC and isothermal crystallization kinetic method revealed the effect of CW on crystallization properties of reversible phase and fixed phase, suggesting that the effect of CW on the crystallization of hard segment phase is not comparable with thermal history; the more CW causes the higher crystallization rate of reversible phase; the crystallization mechanism of reversible phase in nano-composite gradually evolves to heterogeneous nucleation and crystal growth in two dimensions with the increase of CW content; the excellent nucleation effect of CW for the reversible phase leads to the drop of activity energy from 134.1 kJ/mol (N-0), to 95.1 kJ/mol (N-4). Cyclic tensile tests illustrate the addition of CW content can engender rapid shape fixity ability after a relative short cooling time; the shape fixity ratio of nano-composite and the control sample after sufficient cooling all can be identically high. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
-
Morphology, reversible phase crystallization, and thermal sensitive shape memory effect of Cellulose Whisker/SMPU nano‐composites
Journal of Applied Polymer Science, 2011Co-Authors: Jianping Han, Yong Zhu, Hongsheng Luo, Lap-yan Yeung, Qinghao Meng, Sheng Zhang, Ying FanAbstract:To investigate the morphology, crystallization properties of reversible phase and thermal sensitive shape memory properties of CW/SMPU (Cellulose Whisker/Shape Memory Polyurethane) nano-composite, the CW/SMPU nano-composite having CW contents of 0.1–3.8 wt % were prepared. SEM investigation showed the evolution of reversible phase morphology from spherolite crystallization structure to uniform matrix with tiny CW aggregates with the addition of CW into the SMPU matrix. DSC and isothermal crystallization kinetic method revealed the effect of CW on crystallization properties of reversible phase and fixed phase, suggesting that the effect of CW on the crystallization of hard segment phase is not comparable with thermal history; the more CW causes the higher crystallization rate of reversible phase; the crystallization mechanism of reversible phase in nano-composite gradually evolves to heterogeneous nucleation and crystal growth in two dimensions with the increase of CW content; the excellent nucleation effect of CW for the reversible phase leads to the drop of activity energy from 134.1 kJ/mol (N-0), to 95.1 kJ/mol (N-4). Cyclic tensile tests illustrate the addition of CW content can engender rapid shape fixity ability after a relative short cooling time; the shape fixity ratio of nano-composite and the control sample after sufficient cooling all can be identically high. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Alain Dufresne - One of the best experts on this subject based on the ideXlab platform.
-
Effects of polymer‐grafted natural nanocrystals on the structure and mechanical properties of poly(lactic acid): A case of Cellulose Whisker‐graft‐polycaprolactone
Journal of Applied Polymer Science, 2009Co-Authors: Ning Lin, Alain Dufresne, Guangjun Chen, Jin Huang, Peter R ChangAbstract:In this work, polysaccharide nanocrystals—rodlike Cellulose Whiskers (CWs)—were surface-grafted with polycaprolactone (PCL) via microwave-assisted ring-opening polymerization, and filaceous Cellulose Whisker-graft-polycaprolactone (CW-g-PCL) nanoparticles were produced. Moreover, the resultant nanoparticles were incorporated into poly(lactic acid) (PLA) as a matrix, and they showed superior function for enhancing the mechanical performance of PLA-based materials in comparison with platelet-like nanoparticles of starch nanocrystal-graft-PCL. The optimal loading level of CW-g-PCL was 8 wt %, and this resulted in simultaneous enhancements of the strength and elongation of approximately 1.9- and 10.7-fold, respectively, over those of the neat PLA material. In this case, the rigid CW nanoparticles contributed to the endurance of higher stress, whereas the grafted PCL chains improved the association between the PLA matrix and the CW-g-PCL filler and hence facilitated the transfer of stress to the rigid CW nanoparticles. Furthermore, such a fully biodegradable PLA-based nanocomposite shows great potential for environmentally friendly materials because of its high mechanical performance. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
-
effects of polymer grafted natural nanocrystals on the structure and mechanical properties of poly lactic acid a case of Cellulose Whisker graft polycaprolactone
Journal of Applied Polymer Science, 2009Co-Authors: Alain Dufresne, Guangjun Chen, Jin Huang, Peter R ChangAbstract:In this work, polysaccharide nanocrystals—rodlike Cellulose Whiskers (CWs)—were surface-grafted with polycaprolactone (PCL) via microwave-assisted ring-opening polymerization, and filaceous Cellulose Whisker-graft-polycaprolactone (CW-g-PCL) nanoparticles were produced. Moreover, the resultant nanoparticles were incorporated into poly(lactic acid) (PLA) as a matrix, and they showed superior function for enhancing the mechanical performance of PLA-based materials in comparison with platelet-like nanoparticles of starch nanocrystal-graft-PCL. The optimal loading level of CW-g-PCL was 8 wt %, and this resulted in simultaneous enhancements of the strength and elongation of approximately 1.9- and 10.7-fold, respectively, over those of the neat PLA material. In this case, the rigid CW nanoparticles contributed to the endurance of higher stress, whereas the grafted PCL chains improved the association between the PLA matrix and the CW-g-PCL filler and hence facilitated the transfer of stress to the rigid CW nanoparticles. Furthermore, such a fully biodegradable PLA-based nanocomposite shows great potential for environmentally friendly materials because of its high mechanical performance. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
-
Extrusion and Characterization of Functionalized Cellulose Whisker Reinforced Polyethylene Nanocomposites
Polymer, 2009Co-Authors: Aparecido Junior De Menezes, Gilberto Siqueira, Aprigio Curvelo, Alain DufresneAbstract:The surface of ramie Cellulose Whiskers has been chemically modified by grafting organic acid chlorides presenting different lengths of the aliphatic chain by an esterification reaction. The occurrence of the chemical modification was evaluated by FTIR and X-ray photoelectron spectroscopies, elemental analysis and contact angle measurements. The crystallinity of the particles was not altered by the chain grafting, but it was shown that covalently grafted chains were able to crystallize at the Cellulose surface when using C18. Both unmodified and functionalized nanoparticles were extruded with low density polyethylene to prepare nanocomposite materials. The homogeneity of the ensuing nanocomposites was found to increase with the length of the grafted chains. The thermomechanical properties of processed nanocomposites were studied by differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA) and tensile tests. A significant improvement in terms of elongation at break was observed when sufficiently long chains were grafted on the surface of the nanoparticles. It was ascribed to improved dispersion of the nanoparticles within the LDPE matrix.
-
Cross-Linked Nanocomposite Polymer Electrolytes Reinforced with Cellulose Whiskers
Macromolecules, 2004Co-Authors: My Azizi Samir, Jean-yves Sanchez, Fannie Alloin, Alain DufresneAbstract:In a previous work [Macromolecules 2004, 37,1386], a new way of processing Cellulose Whisker reinforced nanocomposites from an organic solvent (N,N-dimethylformamide) without a surfactant addition or a chemical surface modification was investigated. This technique is used to prepare nanocomposite polymer electrolytes based on a cross-linked polyether and lithium imide (LiTFSI) reinforced with tunicin Whiskers. Both the mechanical and ionic conductive properties of the resulting electrolytes are presented. These performances are compared to those obtained for unfilled cross-linked polyether matrices exhibiting several cross-linking densities. It is observed that the ionic conduction of Cellulose Whisker filled electrolytes is higher than the one of highly cross-linked polyether networks. In addition, the mechanical stiffness of the former is much higher than that of the latter, allowing the processing of high-performance nanocomposite polymer electrolytes.
-
morphological investigation of nanocomposites from sorbitol plasticized starch and tunicin Whiskers
Biomacromolecules, 2002Co-Authors: Aji P Mathew, Alain DufresneAbstract:Nanocomposites were prepared from waxy maize starch plasticized with sorbitol as the matrix and a stable aqueous suspension of tunicin Whiskersan animal Celluloseas the reinforcing phase. The composites were conditioned at different relative humidity levels. The conditioned films were characterized using scanning electron microscopy, differential scanning calorimetry, water uptake experiments, and wide-angle X-ray scattering studies. Contrarily to our previous report concerning tunicin Whisker filled glycerol plasticized starch nanocomposites (Macromolecules 2000, 33, 8344), the present system exhibited a single glass−rubber transition, and no evidence of transcrystallization of amylopectin on Cellulose Whisker surfaces and resultant antiplasticizing effects were observed. It was found that the glass−rubber transition temperature of the plasticized amylopectin matrix first increases up a Whiskers content around 10−15 wt % and then decreases. A significant increase in crystallinity was observed in the comp...