At present, water-assisted injection molding is suitable for producing hollow or part of hollow plastic products. The research of viscoelastic properties can provide an improved understanding about the influence of related process parameters on the filling process of water-assisted injection molded parts. In this paper, based on the open source code of OpenFOAM, an analysis module was constructed for the three dimensional isothermal flow of multiphase fluid which can be subscribed as Giesekus viscoelastic model, by the object oriented program and the volume of fluid method(VOF). The filling process of the water-assisted injection molding was simulated by the solver called viscoelastic InterFoam. The result agrees with the experiment of Polynkin, which shows that with increase of the injection rate, the residual wall thickness of melt and penetration distance of water will be increased. That can be analyzed according to viscoelastic properties of melt.
INTRODUCTION Incorporating metal-oxide nanoparticles such as nano-alumina and nano-silica into polymeric coatings to enhance the mechanical durability has become a trend in the current anti-scratch and mar technologies [1]. Recent results [1-2] have shown promising results in the automotive coatings and other thin film coating applications. Other research efforts [3-4] have been focused on the effect on nanofillers on the materials properties of complex systems such as nanocompoites. In these systems, the surface properties may be very different from the bulk properties, the dispersion of the nanofillers and overall microstructure may influence the final properties. In this paper, we investigate a quantitative study on the effect of nano-silica on the surface morphology and mechanical properties on two-dimensional (2D) gradient polymer-silica composite samples varied in chemical composition (e.g., filler size/concentration). A combination of techniques including nanoindentation and laser scanning confocal microscopy was utilized to measure surface modulus and roughness, and map scratch damage patterns. Preliminary results show the addition of nano-silica reduces surface roughness, increases modulus and hardness, and improves scratch resistance of the polymer-silica composite systems.
INTRODUCTION Controlled structuring on the length scale of a few nanometers to 1 μm of surfaces and three-dimensional objects is an attractive challenge . Positioning of small objects (e.g. 5 nm in size) in arrays of larger dimensions (e.g. 100 nm) in an efficient manner is of interest, for example, in the context of the addressing and optical properties of single quantum dots located in larger metal structures functioning as a nano-antenna . We have followed the approach of encapsulation of small inorganic particles in polymer particles . This size enlargement can facilitate manipulation of the particles, sensitive inorganic particles can be protected during further manipulation steps , and an interaction of the organic polymer particle surface with pre-structured arrays can be utilized for positioning.
INTRODUCTION Living olefin polymerization is of interest, for example, for the preparation of well-defined polyolefins with narrow molecular weight distribution, and for the preparation of block copolymers. A limited number of suitable polymerization catalysts is known to date. Fujita et al. have reported bis(phenoxyimine)titanium dichloro complexes with ortho-fluorinated N-aryl moieties to be versatile precursors to living olefin polymerization catalysts. The fluorine substituents are considered to suppress chain transfers by interaction with the βhydrogen atoms of a growing polymer chain. In similar complexes with other N,O-chelating ligands, however, ortho-fluorinated substitution was found not to result in living polymerizations. This raises the question whether retardation of chain transfer by β-H-fluorine interactions is restricted in fact to phenoxyimine complexes, or represents a more general principle.
Hence, the number of applications of the material is huge and many millions of tons are produced worldwide annually. However, PE has hardly played any role in the emerging field of nanotechnology so far. This is due to the problem that PE is either produced by free radical polymerization under high pressure and temperature or with metal-organic catalysts working exclusively under strictly water-free conditions. Polymer nanoparticles and their composites with inorganic compounds, however, are very often produced in aqueous systems.
Marine biofouling is a serious problem caused by the accumulation and settlement of barnacles, macroalgae, and microbial slimes on the hulls of seafaring vessels. Biofouling can significantly increase drag, leading to startling consequences with regards to fuel consumption. Environmentally compatible solutions to biofouling are being sought as traditional metal-based systems of fouling control are being phased out due to their inherent toxicity. Further exasperating the problem of biofouling is the vast range of fouling organisms and environmental conditions experienced throughout the world. This renders the development of a universal biofouling coating a significant challenge.
