Advanced Materials Research Vols. 1033-1034

Abstract: In order to improve the strength and toughness of materials, nanoparticle is always embedded into epoxy resin and fiber composite materials. The influence of the number, distribution and mechanical property of nanoparticle arranged around the fiber on fiber reinforced composites is evaluated in this paper. A finite element analysis under a tensile load is performed by using commercial finite element software named as ABAQUS. Both the stress contour and progressive damage failure mode of the representative volume element (RVE) model of fiber reinforced composites are obtained. A series of computational experimental results indicate that both the space geometry property and mechanical property of nanoparticle have a significant effect on the stiffness and strength properties of these composite materials.

Abstract: TiC/Fe composites were successfully fabricated in situ by self-propagating high temperature synthesis (SHS) technology. The effect of Fe content on the microstructure of the synthetic products was discussed. Results showed that the SHS products of Ti-C-30wt%Fe system were mainly composed of TiC and Fe as well as a few Fe₂Ti.Spherical TiC particles with 2-3μm distributed on the Fe matrix uniformly. With the increase of Fe content, the combustion temperature reduced, resulting in the decrease of growth rate of TiC particles.

Abstract: Infrared spectra of the pyrolysis gases of polyurethane foam flame retarded by MPOP, MP, MC, magnesium hydroxide, or antimony trioxide flame retardants was analyzed online by FTIR method. At 600°C, the polyurethane foam flame retarded by MPOP, MP, MC, magnesium hydroxide or antimony trioxide flame retardants released more hydrogen cyanide than the pure polyurethane foam, proved that the MPOP, MP, MC and magnesium hydroxide flame retardants could change the law that the polyurethane released hydrogen cyanide. At 600 °C, the peak of C=O stretching vibration at 1730cm^-1 did not appear for the flame-retardant polyurethane, indicating that the flame retardants can make the polyurethane rapidly carbonize and the fewer C=O intermediate was produced. The absorbent peaks of the fire-retardant samples at 1604cm^-1, 1538 cm^-1, 1250 to 1230 cm^-1 and 1450cm^-1 implied that the flame retardants could delay the oxidative decomposition of the polyurethane component at 600 °C, so that more components may be carbonized. When increasing the pyrolysis temperature, the perlite would make polyurethane foam release fewer hydrogen cyanide.

Abstract: Rare earth oxides co-doped zirconia has been developed for application in thermal barrier coating (TBC) systems to promote the performance and durability. In this paper, the phase stability and thermal physical properties of 1mol.%La₂O₃, 4.5mol.%Y₂O₃ stabilized ZrO₂ (LaYSZ) were investigated. After 100 h heat treated at 1400°C, the content of monoclinic phase in LaYSZ was 2.32 mol%, which is lower than that in YSZ (46.9 mol%). Result indicates that the LaYSZ has better phase stability and lower thermal conductivity than YSZ. The LaYSZ system can be explored as the candidate material as ceramic layer in TBC.

Abstract: In an attempt to improve the properties of natural rubber-based medical products, natural rubber (NR) was blended with chitosan (CS) and poly(3-hydroxybutyrate) (PHB) in an laboratory type internal mixer, with the total amount of CS and PHB is of 1, 3, 5, 10, 15 and 20 parts per hundred rubber (phr) , and CS and PHB is of a ratio of 1:1. The testing for processing properties of NR/CS/PHB compounds showed that the Mooney viscosity of NR/CS/PHB compounds increased with the addition of 1.0 phr CS/PHB and then decreased with increase in CS/PHB content, but the Mooney viscosity of each NR/CS/PHB compound was higher than that of NR compound; the minimum torque (M_L) increased only slightly, while the maximum torque (M_H) increased gradually, with increase in NR/CS/PHB content; the scorching tendency of NR/CS/PHB compounds increased with the increase in CS/PHB content; the optimum cure time (t₉₀) decreased firstly, then increased with increase in CS/PHB content, and was not greatly different from that of NR compound. The results of mechanical properties of NR/CS/PHB vulcanizates showed that the tensile strength and elongation at break deceased, whereas the 300% and 500% moduli, tear strength and hardness increased, with increase in CS/PHB content.

Abstract: Aluminum hypophosphite can be used to flame retard glass fiber reinforced polyamide 6 (GFPA6). TGIC microcapsulated AlHP (T-AlHP) and epoxy resin microcapsulated AlHP (E-AlHP) were made and put into GFPA6. The vertical burning tests and mechanical tests were taken to study the flame retardant performance and mechanical properties of the corresponding composites. Addition of either T-AlHP or E-AlHP resulted in an increased UL-94 rating and a decreased comprehensive mechanical performance. T-AlHP endowed GFPA6 a better flame retardancy than E-AlHP did. TG showed the decomposition behaviors of T-AlHP, E-AlHP, and the corresponding composites. From Py-GC/MS, the detailed pyrolysis products of flame retardants and the flame-retardant composites were identified. Finally, the properties and mechanism of flame retarded GFPA6 with these two kinds of microcapsulated Aluminum Phosphate were summarized.

Abstract: The tensile mechanical properties of polyethylene/silica (PE/SiO₂) composite fiber and three-strand PE/SiO₂ composite fiber ropes were investigated. It was found that the SiO₂ content had a significant effect on the tensile mechanical properties of composite fiber. The breaking force of the fishing three-strand PE/SiO₂ composite fiber rope with diameter 8 mm was 15.8 kN. Compared to common synthetic fiber rope with the same diameter, fishing three-strand PE/SiO₂ composite fiber rope had higher breaking force and less elongation. On the premise of maintain the breaking force, the common synthetic fiber rope could be replaced by the fishing three-strand PE/SiO₂ composite fiber rope in fishing area, and the linear density, the elongation at break, the netting gear resistance and using diameter of rope decreased. Therefore, an efficient method to improve the tensile mechanical properties and lower cost by using composite fiber rope was established.

Abstract: Liquid crystalline thermosetting epoxy, 4,4’-Diglycidyloxy-α-methylstilbene (DOMS) was synthesized and characterized with cross-polarized optical microscopy (POM) and differential scanning calorimetry (DSC). Alumina reinforced DOMS composites were fabricated by melt blending with sulfanilamide (SAA) as a curing agent. To investigate thermal degradation behavior, thermogravimetric analysis (TGA) was performed under nitrogen atmosphere at the temperature range from 30 to 1000°C. Activation energies for decomposition (Ed) by TGA were determined as a function of conversion by weight loss process.

Abstract: A novel intumescent flame retardant (IFR) containing ferrocene and caged bicyclic phosphate groups, 1-oxo-4-[4'-(ferrocene carboxylic acid phenyl ester)] amide-2, 6, 7-trioxa-1-phosphabicyclo- [2.2.2] octane (PFAM), was successfully synthesized. The synthesized PFAM were added to flammable polyurethane (PU) as flame retardants and smoke suppressants. The structure of PFAM was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹H NMR) and elemental analysis. Thermal stability of PFAM was tested by themogravimetric analysis (TGA). The results revealed that PFAM had good thermal stability and high char weight, the char weight up to 54% at 600 °C. Flammability properties of PU/PFAM composites were investigated by limiting oxygen index (LOI) test and UL-94 test, respectively. The results of LOI tests showed that the addition of PFAM enhanced flame retardancy of PU. When the content of PFAM reaches to 3%, the LOI value is 22.2. The morphologies of the char for PU and PU/3% PFAM composite can be obtained after LOI testing were examined by SEM. The results demonstrated that PFAM could promote to form the compact and dense intumescent char layer. Experiments showed that, the PFAM application of polyurethane showed positive effect.

Abstract: A calculation method for prediction of water permeability through polymers is suggested. An appropriate equation for calculating the activation free energy of permeability is proposed. The method is based on a set of atomic constants associated with the polymer-water interaction energy. The chemical structure of polymers as well as the degree of crystallininty, temperature, and free volume are taken into account. The method is also applicable for polymeric nanocomposites.