Papers by Keyword: Interfacial Interaction

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Authors: Yu Mei Xiao, Xu Dong Li, Hong Song Fan, Xiang Dong Zhu, Li Zhao Teng, Zhong Wei Gu, Xing Dong Zhang
Abstract: Good interfacial interaction is crucial for preparation of inorganic-organic materials at a nanometer level. Poly(α-methacrylic acid) (PMAA) was grafted on the PLA surfaces via photooxidization and subsequent UV induced polymerization in an attempt to synthesize nano-hydroxyapatite/poly(lactide) (n-HA/PLA) composites. Grafting of PMAA on the PLA surface was confirmed using FTIR analysis and the size distribution measurement of the grafted-PLA (g-PLA) particles. n-HA/g-PLA composites were in situ synthesized via dropwise addition of Ca2+- and g-PLA containing solution to PO4 3-- solution. The prepared composites were characterized by FTIR, XRD,SEM and TEM means. Analytical results indicated that the g-PLA acts as a template to manipulate the nucleation and growth of n-HA crystals and thereby to control the morphology, size and anisotropy of n-HA crystals and their distribution over the organic phase. Chemical linkages and/or interfacial interactions between the n-HA and the g-PLA in the n-HA/g-PLA composite were further discussed.
Authors: Qing Hua Zeng, Ai Bing Yu, Gao Qing Max Lu
Abstract: Polymer nanocomposites are recognized as the next generation of polymer composites due to their exceptional properties. Understanding the molecular origin of the reinforcement mechanism is crucial to the development of such promising materials. This paper reports our recent molecular dynamic study on clay-based polyurethane nanocomposites. The effect of clay platelets on phase separation behavior of polyurethane, at the clay-polyurethane interface, is quantified in terms of molecular interactions, structure and dynamics. The results show that the nanoconfinement of polyurethane chains in clay gallery impedes the development of phase separation commonly observed in bulk polyurethane. The absence of phase separation of intercalated polyurethane is believed to be related to the competitive interactions among clay platelet, polyurethane and surfactant.
Authors: Xiao Ya Yuan
Abstract: The graphene/poly(vinyl alcohol) nancomposites with enhanced filler-matrix interfacial interaction were fabricated via water-blending partially reduced graphene oxide (PRGO) and poly(vinyl alcohol)(PVA). The nanocomposites were characterized by X-ray Diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), Scanning Electron Microscopy(SEM), thermogravimetry(TG). The results showed that the graphene nanosheets were homogeniously dispersed in the PVA matrix and enhanced interfacial adhesion was greatly enhanced due to new covalent linkage and hydrogen-bonding between graphene and PVA backbone. The mechanical and thermal properties of the nanocomposites were significantly improved at low graphene loadings. An 116% increase in tensile strength and a 19°C improvement of onset thermal degradation temperature were achieved by the addition of only 0.8 wt% graphene.
Authors: A. Yamashita, Seiichiro Higashi, S.T. Komatsu, A. Takahara, T. Kajiyama
Authors: Chong He Li, Yong Hui Gao, Xiong Gang Lu, Wei Zhong Ding, Zhong Ming Ren, Kang Deng
Abstract: The CaZrO3 complex oxide ceramic was synthesized in the development of the potential refractory for melting of titanium alloy, the crucible ( 40XH40mm) was prepared by the solid sintering of mixture of powder (CaO:ZrO2 =1:1) with a small amount of TiO2 as additive at 1750°C. The melting of TiNi and Ti6Al4V was carried out in the inducting furnace under vacuum or/and Ar atmosphere. The interfacial reaction between the melts of alloys and CaZrO3 refractory was investigated by scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS). It is found that, the thickness of interfacial reaction layer between the ceramic CaZrO3 and the melt of titanium alloys (TiNi and Ti6Al4V) is approximately 30-300 μm, there are few elements such as Ca, Zr, Ti, and Ni diffused through the interfacial reaction layer. These results may provide the basement to designing a novel refractory for melting of titanium alloys.
Authors: Vasil I. Dybkov
Abstract: A physico-chemical consideration of the interfacial interaction and diffusion resulting in the formation of chemical compound layers at the interface of initial substances A and B is presented. The layer-growth kinetics is shown to be much more complicated than it follows from conventional diffusional views neglecting interfacial reactions. In the majority of multiphase binary systems, layer occurrence appears to be sequential rather than simultaneous. Under conditions of diffusion control, the number of simultaneously growing compound layers at the A–B interface cannot exceed two. Multiple layers (three and more) can only form as a result of secondary processes connected with the rupture of a diffusion couple. In such cases, great care is necessary when calculating diffusion coefficients to avoid obtaining their physically meaningless values.
Authors: I.A. Key, S. Pina, Simeon Agathopoulos, D.U. Tulyaganov, José Maria F. Ferreira
Abstract: In the framework of producing new composite biomaterials, this study investigated the interfacial interactions between molten brand new biocompatible glasses with model formulations and Ti, hydroxyapatite, zirconia and a CrNi-steel. Analysis, by grouping the results of each particular substrate, indicates that Ti reduces the molten glass-oxides, HA tends to diffuse with them, zirconia grain-boundaries are vulnerable towards them, and Cr-Ni-steel very poorly adhere to them. Analysis, by grouping the results of each particular glass, indicates that the matching of their expansion coefficient with that of substrate and crystallization affect the formation of continuous or cracked interface. Viscosity and surface tension of glasses determine wettability. Wettability is not however determinative index of evaluating the quality and the strength of the resulting interfaces.
Authors: Wei Zhou, Shao Jie Yue, Jun Jun Wang, Bo Wang, Ya Ping Zheng
Abstract: Epoxy nanocomposites with multi-walled carbon nanotubes (MWNTs) were prepared. The interaction between MWNTs and epoxy matrix and microstructure were systematically investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and the positron annihilation technology (PAT) respectively. The glass transition temperatures were determined by the variation of the free volume size.
Authors: Wen Qian Xiao, Yu Mei Xiao, Xian Tao Wen, Hong Song Fan, Xing Dong Zhang
Abstract: In order to prepare nano-hydroxyapatite/poly(lactide) (n-HA/PLA) composite with good interfacial interaction, some groups which could bind with Ca ions in HA crystals need to be introduced onto PLA surface. Poly(α-methacrylic acid) (PMAA) was grafted on the PLA surfaces via photooxidization and subsequent UV induced polymerization. Suspension of PMAA-PLA microparticles with an average size as 133.1nm was prepared with solvent evaporation technique. Then utilizing the action of template manipulating of PMAA-PLA microparticles, n-HA/PLA composite were synthesized. Zeta potentials measurement and SEM indicated that there were good interfacial interactions between two phases of n-HA/PLA composite. The results of cell viability confirmed that n-HA/PLA composite possessed good cytocompatibility, so the n-HA/PLA composite scaffold obtained by electrospun technology might be used as bone tissue engineering scaffold.
Authors: Xiao Ling Xu, Min Zhang, Ji Qing Song, Wen Qing He
Abstract: Novel liquid composites were successfully prepared by blending copolymer (PEG/PHS) and carboxymethyl cellulose (CMC) in this work. PEG/PHS was achieved by introducing polyethylene glycol (PEG) into the main chain of poly hexanediol succinic (PHS). The results showed that the structure characterization of PEG/PHS was displayed in 1H NMR spectrum. The interaction existed between PEG/PHS and CMC which was validated in FT-IR and SEM. This conjecture was simulated by molecular dynamics under the software YASARA. Because of the existence of interfacial interaction, composites films kept good thermal performance and the flexibility of composite films was greatly improved.
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