In this work, hybrid conductive fillers of carbon black （CB） and carbon nanotubes （CNTs） were introduced into polylactide （PLA）/thermoplastic poly（ether）urethane （TPU） blend （70/30 by weight） to tune the p...In this work, hybrid conductive fillers of carbon black （CB） and carbon nanotubes （CNTs） were introduced into polylactide （PLA）/thermoplastic poly（ether）urethane （TPU） blend （70/30 by weight） to tune the phase morphology and realize rapid electrically actuated shape memory effect （SME）. Particularly, the dispersion of conductive fillers, the phase morphology, the electrical conductivities and the shape memory properties of the composites containing CB or CB/CNTs were comparatively investigated. The results suggested that both CB and CNTs were selectively localized in TPU phase, and induced the morphological change from the sea-island structure to the co-continuous structure. The presence of CNTs resulted in a denser CB/CNTs network, which enhanced the continuity of TPU phase. Because the formed continuous TPU phase provided stronger recovery driving force, the PLA/TPU/CB/CNTs composites showed better shape recovery properties compared with the PLA/TPU/CB composites at the same CB content. Moreover, the CB and CNTs exerted a synergistic effect on enhancing the electrical conduetivities of the composites. As a result, the prepared composites exhibited excellent electrically actuated SME and the shape recovery speed was also greatly enhanced. This work demonstrated a promising strategy to achieve rapid electrically actuated SME via the addition of hybrid nanoparticles with self-networking ability in binary PLA/TPU blends over a much larger composition range.展开更多
In this article, hybrid fillers with different dimensions, namely, 2-dimensional（2-D） expanded graphite（EG） and 1-dimensional（1-D） multi-walled carbon nanotubes（CNTs）, were added to aromatic nylon MXD6 matrix ...In this article, hybrid fillers with different dimensions, namely, 2-dimensional（2-D） expanded graphite（EG） and 1-dimensional（1-D） multi-walled carbon nanotubes（CNTs）, were added to aromatic nylon MXD6 matrix via melt-blending, to enhance its thermal and electrical conductivity as well as electromagnetic interference shielding effectiveness（EMI SE）. For ternary composites of MXD6/EG/CNTs, the electrical conductivity reaches up nine orders of magnitude higher compared to that of the neat MXD6 sample, which turned the polymer-based composites from an insulator to a conductor, and the thermal conductivity has been enhanced by 477% compared with that of neat MXD6 sample. Meanwhile, the EMI SE of ternary composite reaches ~50 d B at the overall filler loading of only 18 wt%. This work can provide guidance for the preparation of polymer composites with excellent thermal and electrical conductivity via using hybrid filler.展开更多
Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H2O2) and distilled...Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H2O2) and distilled water(H2O). The functional groups on the surface of CNTs, changes in nanotube structure and morphology were characterized by Fourier transform infrared spectroscopy(FT-IR), Raman Spectroscopy, and transmission electron microscopy(TEM). It shows that hydroxyl(OH·) is successfully introduced. The surface defects of modified CNTs were obviously higher than those of original CNTs, and the degree of agglomeration was greatly reduced. Thermal conductivity of the composites was tested by protection heat flow meter method. Compared with unmodified CNTs/CB filling system, the thermal conductivity of hybrid composites is improved by an average of 5.8% with 1.5 phr(phr is parts per hundred rubber) of hydroxyl CNTs and 40 phr of CB filled. A three-dimensional heat conduction network composed of hydroxyl CNTs and CB, as observed by TEM, contributes to the good properties. Thermal conductivity of the hybrid composites increases as temperature rises. The mechanical properties of hybrid composites are also good with hydroxyl CNTs filled nanocomposites;the tensile strength, 100% and 300% tensile stress are improved by 10.1%, 22.4% and 26.2% respectively.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51421061 and 51210005)
文摘In this work, hybrid conductive fillers of carbon black （CB） and carbon nanotubes （CNTs） were introduced into polylactide （PLA）/thermoplastic poly（ether）urethane （TPU） blend （70/30 by weight） to tune the phase morphology and realize rapid electrically actuated shape memory effect （SME）. Particularly, the dispersion of conductive fillers, the phase morphology, the electrical conductivities and the shape memory properties of the composites containing CB or CB/CNTs were comparatively investigated. The results suggested that both CB and CNTs were selectively localized in TPU phase, and induced the morphological change from the sea-island structure to the co-continuous structure. The presence of CNTs resulted in a denser CB/CNTs network, which enhanced the continuity of TPU phase. Because the formed continuous TPU phase provided stronger recovery driving force, the PLA/TPU/CB/CNTs composites showed better shape recovery properties compared with the PLA/TPU/CB composites at the same CB content. Moreover, the CB and CNTs exerted a synergistic effect on enhancing the electrical conduetivities of the composites. As a result, the prepared composites exhibited excellent electrically actuated SME and the shape recovery speed was also greatly enhanced. This work demonstrated a promising strategy to achieve rapid electrically actuated SME via the addition of hybrid nanoparticles with self-networking ability in binary PLA/TPU blends over a much larger composition range.
基金financially supported by the National Natural Science Foundation of China(Nos.21274095 and 51573102)
文摘In this article, hybrid fillers with different dimensions, namely, 2-dimensional（2-D） expanded graphite（EG） and 1-dimensional（1-D） multi-walled carbon nanotubes（CNTs）, were added to aromatic nylon MXD6 matrix via melt-blending, to enhance its thermal and electrical conductivity as well as electromagnetic interference shielding effectiveness（EMI SE）. For ternary composites of MXD6/EG/CNTs, the electrical conductivity reaches up nine orders of magnitude higher compared to that of the neat MXD6 sample, which turned the polymer-based composites from an insulator to a conductor, and the thermal conductivity has been enhanced by 477% compared with that of neat MXD6 sample. Meanwhile, the EMI SE of ternary composite reaches ~50 d B at the overall filler loading of only 18 wt%. This work can provide guidance for the preparation of polymer composites with excellent thermal and electrical conductivity via using hybrid filler.
基金Supported by the National Natural Science Foundation of China(51606107,51576102)the Collaborative Innovation Project of Green Tire and Rubber(0200501436)
文摘Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H2O2) and distilled water(H2O). The functional groups on the surface of CNTs, changes in nanotube structure and morphology were characterized by Fourier transform infrared spectroscopy(FT-IR), Raman Spectroscopy, and transmission electron microscopy(TEM). It shows that hydroxyl(OH·) is successfully introduced. The surface defects of modified CNTs were obviously higher than those of original CNTs, and the degree of agglomeration was greatly reduced. Thermal conductivity of the composites was tested by protection heat flow meter method. Compared with unmodified CNTs/CB filling system, the thermal conductivity of hybrid composites is improved by an average of 5.8% with 1.5 phr(phr is parts per hundred rubber) of hydroxyl CNTs and 40 phr of CB filled. A three-dimensional heat conduction network composed of hydroxyl CNTs and CB, as observed by TEM, contributes to the good properties. Thermal conductivity of the hybrid composites increases as temperature rises. The mechanical properties of hybrid composites are also good with hydroxyl CNTs filled nanocomposites;the tensile strength, 100% and 300% tensile stress are improved by 10.1%, 22.4% and 26.2% respectively.
