Advanced Materials Research Vols. 250-253

Abstract: In order to comprehensive understand and control volatile organic compounds (VOCs) release from particleboards, this paper takes Larix gmelini particleboard as example and analyzes VOCs by three different methods. First of all, VOCs of Larix gmelini particles were detected by the static head space solid-phase micro-extraction (HS-SPME) technique. Secondly Larix gmelini particleboards were analyzed using the method of adsorbed by activated carbon, desorpted with methylene dichloride and measured by GC/MS. Finally, Tenax-T Thermal desorption -GC/MS was used to qualitative VOCs emissions. The best method for determination VOCs from particleboards was found. SPME is a simple operation method with short time. But the pretreatment of sample was troublesome and it is not easily measured for lower concentration particleboards. Active carbon absorption method is not suitable for quantitative because of much error in extraction. It is suitable for qualitative analysis. Tenax-T is a simple operation way with short analysis time and good shape of chromatographic. It is a convenient and practical method. Further study of VOCs emission of panels can be supported by this method.

Abstract: Longitudinal and transverse modulus of rupture(MOR) tests of plybamboo form with different moisture content were performed. The results show that both longitudinal MOR and transverse MOR decrease with the increasing of the moisture content of the plybamboo form. At low moisture content stage MOR of the plybamboo form decrease linearly with the increasing of the moisture content of the plybamboo form. Curve regression equations of longitudinal and transverse MOR of plybamboo form were constructed by the method of numerical fitting, and linear regression equations at low moisture content stage were also constructed. Decline of plybamboo form strength itself and bonding invalidation lead to the decrease of MOR. The results of variance analysis and significance test of four regression equations show that all the regression equations achieve very significant level.

Abstract: The purpose of this study is to reveal the concentration variations of VOC concentrations of larch particleboards with different processing parameters. The mat moisture content (MC), panel type and density were chosen as the influencing factors to investigate the VOC emissions after processing, and consequently provide basic guideline for the selection of processing parameters of particleboards to control the pollutants. 1m³ environmental chamber and portable VOC monitor were used for VOC sampling and analysis. The results showed that these factors had significant impact on VOC concentrations. The increase of MC, board panel and density had a positive effect on VOC emissions. With the MC and board density various in the ranges from 6%-14% and 0.60-0.80 g·cm^-3, the TVOC concentrations increased 42.6% and 74.7% separately. The three layers particleboard had the higher concentration than the single layer particleboard.

Abstract: This paper explored the effect of MDI, UF and FRW content on the mechanical and fire retardant property of straw based panels with surface alkali liquor processing. In order to manufacture the straw based panel with high quality, low toxic and fire retardant, the interface of wheat-straw was treated with alkaline liquid under the optimal treating condition: alkaline liquid concentration was 0.4-0.8%, alkaline dosage was 1:2.5-1:4.5, alkaline-treated time was 12h-48h.The physical and mechanical properties of wheat-straw boards after treated could satisfy the China national standard. And the variance analysis of the fire retardant property of straw based panel showed that TTI, pkHRR and peak value appearance time were not affected by the MDI, UF and FRW content significantly. The results of orthogonal test showed that the optimized processing condition was MDI content as 4%, UF resin content as 7% and the FRW content as 10%.

Abstract: New composite foams were prepared by using Melamine-Urea-Formaldehyde (MUF) resin and wood pulp fiber as raw materials with co-foaming method at 70°C in the opening mould. The study of the composites foam microstructure showed good adhesion between MUF matrix foam and wood pulp fiber. The flame-retardant, mechanical, anti-brittleness and insulation properties of composite foam were excellent. The results indicated that composites had superior properties enough to replace the conventional foam materials.

Abstract: The study reported here involves the evaluation of the ultimate bending stress (bending strength) of hybrid sandwich panels using a simple comparative statistical analysis. Four sets of beam were tested with each set consisting of modified beams (MB) and unmodified beam (UB) samples. A total of 42 beam samples were tested using 3 point bending followed by statistical inference analysis using a t-test. The results show that the introduction of an intermediate layer has a significant effect on increasing the bending strength of the new hybrid sandwich panel composite.

Abstract: Fly ash based geopolymer concrete is gaining importance in the context of developing alternatives to cement concrete. The research work available in the literature shows many beneficial effects of the material in terms of its high early compressive strength, tensile strength, reduced shrinkage, good acid resistance etc., However, there are very few studies carried out on the influence of sustained elevated temperature on the properties of geopolymer concrete. This paper presents the results of some of the properties of fly ash based geopolymer concrete activated using sodium silicate and sodium hydroxide and subjected to elevated temperature at 150°C, 200°C, 300°C, 400ºc under sustained durations of 1 hour, 2 hours and 4 hours. The results show that residual compressive strength is about 20% less than the normal at about 200°C itself possibly due to the development of vapour pressure formed by the non-reactive water present in the system. Beyond 2 hours of sustenance, there is not much of a difference in the properties of concrete.

Abstract: As a green building material, the demand for plaster board is growing with the promotion of the wall materials reform policy and development of the construction industry in China. In terms of its production technology, the technique formula of the raw materials for gypsum board is not only the main factors to determine the quality, but also determine the use of equipment related to production technology. In this paper, according to the actual production conditions of Beijing New Building Materials Group Industrial Park in Zhuozhou, water-reducing agent is introduced in its raw materials and specific researches are made about the properties of gypsum when water reducer, foam, coagulant agent and other additives are mixed. The results show that the suitable water-reducing agent used in conjunction with other gypsum admixtures not only improve the quality, but also play an important role in saving energy, improving production efficiency, and reducing production costs.

Abstract: Due to the versatility of the biomass, this article reviews the research and development of polyurethane foams based on starch, rosin, oil, cellulose and lignin. The study on biodegradable polyurethane foams become hotspot in recent years. An awareness of the various structures and compositions of renewable resource can be used to make a strong case for an increase in its production as a vital raw material for the polyurethane industries.

Abstract: In the pile driving process, the soil dynamic performance and the dynamic contact on the interface are very complex. In order to analyze the interactions between the pile and soil, the simulation model of the pile-soil system is created by the finite element software. The numerical solution and the displacement curves of the pile are obtained based on suitable parameters of the pile-soil system and the D-P criterion. Then the amplitude and the frequency of the exciting force as well as the stiffness and the damping of the soil are changed to obtain the displacement curves of the pile. Through the comparisons between the curves, the influences on the pile driving process coming from the exciting force and other parameters are found out.