With an industrial trend of going green, the use of natural fibers in polymer composites is growing rapidly, especially in the automotive industry. The objectives of this research are to investigate the processability...
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ISBN:
(纸本)9781934551127
With an industrial trend of going green, the use of natural fibers in polymer composites is growing rapidly, especially in the automotive industry. The objectives of this research are to investigate the processability of kenaf fibers in making nonwoven composites for automotive interior parts and to explore the composite end-use performance in terms of physical structure, mechanical properties, thermal stability, and acoustical behavior. The kenaf/polypropylene(KF/PP) composites were fabricated with 50/50 blend ratio by weight. All nonwovens were produced by carding and needle-punching techniques and thermally bonded by a panel press. The tensile, three-point bending and in-plane shearing tests were performed to evaluate the composite mechanical properties. Based on the mechanical tests, the optimum processing conditions were determined. Dynamic mechanical analysis (DMA) was used to measure the thermal-mechanical properties of composites. The sound absorption and sound insulation performance was evaluated. The correlation between mechanical properties and acoustical behavior was also verified by the panel resonance theory.
Dielectric polymers with high energy density with low loss at high electric fields are highly desired for many energy storage and regulation applications. A polar-fluoropolymer blend consisting of a high energy densit...
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Dielectric polymers with high energy density with low loss at high electric fields are highly desired for many energy storage and regulation applications. A polar-fluoropolymer blend consisting of a high energy density polar-fluoropolymer of poly(vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-CTFE)) with a low dielectric loss polymer of poly(ethylene-chlorotrifluoroethylene) (ECTFE) was developed and investigated. We show that the two polymers are partially miscible which leads to blends with high energy density and low loss. Moreover, by introducing crosslinking to further tailor the nano-structures of the blends a markedly reduction of losses in the blend films at high field can be achieved. The crosslinked blend films show a dielectric constant of 7 with a dielectric loss of 1% at low field. Furthermore, the blends maintain a high energy density and low loss (∼3%) at high electric fields (> 250 MV/m).
Atomic force microscopy (AFM) has been used to investigate the atomic-scale mechanisms of growth of GaAs by metal organic vapor phase epitaxy (MOVPE). The influence of impurities such as silicon, oxygen and carbon on ...
Atomic force microscopy (AFM) has been used to investigate the atomic-scale mechanisms of growth of GaAs by metal organic vapor phase epitaxy (MOVPE). The influence of impurities such as silicon, oxygen and carbon on the small-scale periodic structure as well as on the large-scale features has been studied. The growth front of GaAs epitaxial films grown on vicinal GaAs (100) substrates exhibits periodic structure except for the Si doped GaAs grown on semi-insulating vicinal GaAs (100) substrates. The periodicity on the surface breaks down when oxygen, silicon or carbon concentration exceeds 1018cm−3. These impurities may preferentially attach at the step edges resulting in reduction of the mobility of the steps. At higher impurity concentrations, the motion of the growth front gets pinned on the surface resulting in a disruption of the step flow mode of growth. The wide terraces on Si doped GaAs grown on semi-insulating substrate is proposed as the kinetic limited step bunching during the step flow mode of growth.
The helical and tubular structures self‐assembled from proteins have inspired scientists to design synthetic building blocks that can be"polymerized"into supramolecular polymers through coordinated no
The helical and tubular structures self‐assembled from proteins have inspired scientists to design synthetic building blocks that can be"polymerized"into supramolecular polymers through coordinated no
Polylactide (PLA) nanocomposites containing inorganic nanofillers, either 3 wt.% montmorillonite (MMT) or 5 wt.% nano-sizes calcium carbonate (NCC), and 15 wt.% cellulose fibres were prepared and studied. Good dispers...
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ISBN:
(纸本)9788888785332
Polylactide (PLA) nanocomposites containing inorganic nanofillers, either 3 wt.% montmorillonite (MMT) or 5 wt.% nano-sizes calcium carbonate (NCC), and 15 wt.% cellulose fibres were prepared and studied. Good dispersion of nanoparticles in the PLA matrix was obtained. X-ray analysis and TEM examination evidenced that exfoliation of MMT was achieved. Dynamic mechanical response, thermal and mechanical properties, and also thermal stability of the composite materials were investigated with various methods. All the fillers, especially MMT, enhanced cold crystallization of PLA matrix, possibly by augmenting nucleation.
Using chemical vapor deposition technique, a novel 3D carbon nano-architecture called a pillared graphene nanostructure (PGN) is in situ synthesized. The fabricated novel carbon nanostructure consists of CNT pillars o...
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