Advanced Materials Research Vols. 750-752

Abstract: PS/PP/nano-TiO₂ composites are prepared via melt compounding method. We study on the effects of mechanical properties, rheological, heat stability and microscopic structures on the composites. Results show that the impact resistance performance, compatibility, melt index, etc are associated with the addition amount of TiO₂.

Abstract: Fiber impregnation has been the main obstacle for thermoplastic matrix with high viscosity. This problem could be surmounted by adapting low viscous polymeric precursors Woven basalt fabric reinforced poly (butylenes terephthalate) composites were produced via in-situ polymerization at T=210°C. Before polymerization, catalyst was introduced to the reinforcement surface with different concentration. DSC is used to determine the polymerization and crystallization. SEM is used to detect whether the catalyst existed on surface. Both flexural and short-beam shear test are employed to study the corresponding mechanical properties.

Abstract: Thermosetting matrix composite materials are often subject to a curing process to enhance the mechanical properties of the final product. In recent years computational models of the curing process allowed for a remarkable time and cost compression with respect to trial and error procedures. Most of the proposed models, however, rely on deterministic hypothesis. In this paper a multi-scale non deterministic approach to cure process simulation has been proposed, evidencing the effect of stochastic perturbations of fibers distribution on simulative results on macro-scale.

Abstract: The water vapor permeability and water-swelling property of Polyurethane (PU) membranes with hydrophilic group and the PU composites were investigated. The water vapor permeability of the PU membranes increases with increasing polyethylene glycol (PEG) content. The highest water vapor permeability of PU membrane reaches 5,500 g/m²×24h, whose expansion ratio reaches fifty-eight percent. The PU composites have three PU layers. The best surface layer of the composite is PU with fifteen percent PEG content, and the best base layer is PU with one hundred percent PEG content. The middle layer uses PU with PEG content from fifty to one hundred percent. The water vapor permeability of the PU composites can reach 4,000 g/m²×24h, and the water-expansion ratio of the composites is below four percent when the surface layer of the composites contacts with water.

Abstract: In this paper a three-dimensional tubular braided carbon/carbon composite model is presented, the calculated formula of the fiber volume fraction is deduced and the related performance parameters are calculated. Comparisons of displacements and stresses for the thermo-mechanical coupling are analyzed. The simulation results can help designers to analyze material property.

Abstract: The internal stress calculation of continuous fiber reinforced composites under transverse loads is a complex problem. This paper established a stress calculation model based on "equal strain method", which greatly simplify the formula derivation. Three internal stress formulas under the transverse loads were derived based on the model. The first is the fiber stress formula, which shows that the ratio of fiber stress to load gradually decreases with increasing of fiber volume fraction. The second is the matrix stress formula, which shows the ratio of matrix stress to load gradually increases with increasing of fiber volume fraction. The third is the formula of average shear stress at the interface of fiber and matrix, which curve shows there is a maximum value of interfacial shear stress. The three formulas have important role for checking intensity.

Abstract: The thermo-mechanical coupling finite element models of disc brakes made of aluminum metal matrix composites and cast iron for a passenger car under different emergency braking conditions were deveoped. And the braking process for brake disc was simulated by using finite element method. By analyzing distributions of the temperature field and stress field of the two brake discs with different thickness under emergency braking conditions, the weight reduction of the brake discs by using aluminum metal matrix composites substrate for cast irons was discussed and the simulation resusts showed that brake discs made of aluminum metal matrix composties can be used for passenger cars.

Abstract: In this study,silvergrass (SV) reinforced high density polyethylene (HDPE) composites (WPCs) were prepared by injection molding. The effects of maleated polyethylene (MAPE), Slivergrass fibers (SV) content on the thermal, crystalline properties of WPCs were investigated. It was found that compared with the untreated WPCs, the thermal stability of the composites after incorporation of MAPE was significantly improved. Moreover, the results show that with MAPE adding, SV was an effective heterogeneous nucleating agent.

Abstract: In this study, the silvergrass (SV) was used to reinforce HDPE composites. The effects of polymeric methylene diphenyl diisocyanate (PMDI) content, slivergrass fibers content on the mechanical, water absortion of wood plastic composites (WPCs) were investigated. It was found that the mechanical properties of the SV reinforced HDPE composites can be improved by PMDI treatment. The highest tensile strength and flexural strength of the composites can be reached with 50% SV contents at the SV: PMDI=6:1. It has been proved that the hydroxyl groups of SV fibers which can react with the-NCO by FTIR. It also can be concluded that the water absorption of PMDI treated WPCs was lower than untreated ones.