Advanced Materials Research Vols. 821-822

Abstract: Moisture sorption of wood sawdust panel results in dimensional variation, deterioration of mechanical property and fungi attack, which may be improved by the reinforcement of waterproof material. In this study, the fir sawdust panel was reinforced by basalt glass particles with size smaller than 5 micron, in order to reduce moisture penetration. When the content of basalt glass powder was 15%, both the thickness swelling and 24 h water absorption rate of wood composites reached their minimum values, which were 2.7% and 11%, respectively. The thickness swelling was far smaller than the 45% upper limit of medium density fiberboard as described by standards GB/T17657-1999.

Abstract: Moisture absorption results in dimensional deformation, mechanical property deterioration and fungi attack in wood composite products, which may be improved by the reinforcement of waterproof material. In this study, we used basalt fibre as a reinforcement material for fir sawdust panels and investigated the influence of basalt fibre content and length on moisture absorption rate and thickness swelling. The reinforced fir sawdust panel groups largely reduced water absorption rate, and the smallest thickness swelling occurred when the content of basalt fibre was 5%. The results also indicated that the basalt fibre content played a more important role than basalt fibre length on the thickness swelling of the reinforced fir sawdust panels.

Abstract: shaped weaving is a method which using unequal length of the warp and weft to weave shaped fabrics on the ordinary weaving frames. After multi-layer wound and resin solidified, these shaped fabrics can be formed into whole three-dimensional preform parts, such as oval-shaped pressure vessels, conical tube, ring, etc. because the batch roller on frame is cone frustum, not cylinder, which makes the shear deformation happens when tuck-in fabrics. In this paper, through the establishment of shear deformation model of the annular shaped woven fabric, and theoretical derivation on shear deformation, then calculate the weft deformation angle by theoretical formula. By contrast, we found the calculated shear deformation angle is very near to that measured on the shape fabrics. This proves the shear deformation model and theoretical derivation are correct, accord with the real situation of the shear deformation. Key words: shape woven fabric, shear deformation, theory model,shear angle

Abstract: UHMWPE/LDPE thermoplastic composites present obvious plastic deformation in the off-axis direction, especially in the transverse direction. In this paper, the elastoplastic property of UHMWPE/LDPE composites in transverse tensile direction was studied. Mises yield potential plastic model was used as the plastic model, together with a power hardening law to analyze the plastic behavior of UHMWPE/LDPE composite in transverse direction. Abaqus software and subroutine UMAT were used to simulate the tensile property of UHMWPE/LDPE composites, and the simulation results are accordance with the experiment results very well.

Abstract: Absorbing powders were covered on the surface of radiation-proof fabric by coating technology. Morphology, structure, property, electromagnetic parameters and reflectivity of the coated composite fabric were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD),differential scanning calorimetry (DSC) , thermogravimetry (TG) and microwave network analyzer respectively. The results showed that the coating on the surface of radiation-proof fabric was crystal, acetylene carbon black (ACB) and carbonyl iron powder (CIP) owned better stability of thermodynamics compared with alloy powder (AP). ACB coated composite fabric and CIP coated composite fabric has excellent absorbing effect on the radar X, Ku band, while AP coated composite fabric has absorbing effects on low-frequency.

Abstract: In this article, in order to study the sound insulation properties, abandoned cotton and jute fibers were conducted as reinforced materials, TPU and PP were conducted as matrix materials, and double roller mixing and hot pressing molding processes were adopted to prepare composites. Through the L12 (42×13) mixed orthogonal experiment, cotton/TPU, cotton/PP, jute/TPU and jute/PP composites were prepared respectively. Standing wave tube and impedance tube’s sound absorbing and insulation test system which was produced by Beijing Prestige Company were employed to test the sound insulation (transmission loss). And they were used origin software to analyze. Universal mechanical testing machine and Jane suspension combined impact tester were employed to test tensile, bending and impact strength of jute/TPU composites. Results were showed that four kinds of composites had excellent sound insulation properties. And the jute/TPU composite was the most optimal. Under the conditions of thickness in 6 mm and frequency at 6300Hz, transmission loss of jute/TPU composites was up to 30 dB and it had excellent mechanical properties.

Abstract: The process conditions of making composite particle adsorption material out of hydroxyapatite-chitosan, regeneration method, and how to use composite particle adsorption material to treat industrial sewage containing heavy metals are researched. Experiment consequence shows that when the mass ratio of chitosan to hydroxyapatite is 0.12:1, the concentration of acetic acid is 4%, and liquid-solid ratio is 0.6:1, the granular material will be produced with the best adsorption effect. The dosage of composite particle adsorption material is 0.025 g/mL, the adsorption time is 60 min, and the temperature is 25 °C , removal percentage of Cd²⁺, Pb²⁺ and Zn²⁺ is 99.25%, 75.16% and 79.33% respectively. The isothermal adsorption equation is C_Cd/Q = 1.323C_Cd + 0.1338. Adsorption selective sequence is: Cd²⁺ > Zn²⁺ >Pb²⁺ . When we use 1 mol/L NaCl to regenerate composite particle adsorption material, it still can be employed to deal with sewage with a good effect.

Abstract: Warp knitted fabrics possess a number of changes in the structures, so they do have great advantages on the property design of composites. The three kinds of weft insertion warp knitted fabrics are knitted on a Raschel latch needle warp knitting machine with glass continuous-filament yarns. The warp knitted fabric/ unsaturated polyester resin composite laminates are produced by manual molding technology. The tensile properties of composites in the course, wale and diagonal directions are tested on the universal material testing machine. The results show that the tensile stress/strain curves of the composites were nonlinear. The tensile properties of the composites possess obvious anisotropic characteristics. The tensile strengths and elastic modulus of the warp knitting composites depend on the needle space number of inlaid yarn, fabric density and structure.

Abstract: In order to improve the hardness and strength of the permeable concrete, rigid polymeric fibers are mixed to the concrete. Compressive strength tests, flexural strength tests, tensile splitting strength tests and permeable performance tests prove that the rigid polymeric fibers could increase the hardness and strength of the permeable concrete. The optimized mix proportion and forming process are recommended to support the application of the permeable concrete.

Abstract: SiC/Al₂O₃ composite porous ceramics were prepared by an in situ reaction bonding technique and sintering in air with SiC and A1(OH)₃ as starting materials. The pores in the ceramics were formed by stacking particles of SiC and A1₂O₃. The surface of SiC was oxidized to SiO₂ at high temperature. With further increasing the temperature, SiO₂ reacted with A1₂O₃ to form mullite. The reaction bonding characteristics, phase composition, and mechanical strength as well as microstructure of porous SiC ceramics were investigated.