Papers by Keyword: Thickness Swelling

Abstract: In this paper, three type of natural-fibre reinforced polyethylene were produced. They are the coconut coir reinforced polyethylene (RPCC), kenaf reinforced polyethylene (RPKC) and bamboo reinforced polyethylene (RPBC). Water absorption test, thickness swelling test and tensile test of the different natural fibre composites were carried-out. The mass of HDPE and natural fibre were based on percentage of filler loading. Each board types were produced with two fibre ratios which are at fourty percent and thirty percent. The preparation of the test sample is according to ASTM D1037 and ASTM D638. The tensile modulus of elasticity, tensile stress, water absorption and thickness swelling of kenaf and bamboo reinforced polyethylene composites were found to increase with increasing fibre weight fraction. Kenaf and bamboo composites showed compatible result for tensile stress and tensile modulus of elasticity while coconut coir appears to be otherwise. However, coconut coir fibre composites displayed comparable results to kenaf and bamboo for both water and thickness swelling. There were significant differences in both tensile properties and the percentage of the water absorption among composites.

Abstract: This paper investigated the effect of density and thickness on flexural strength and dimensional stability of laminated floor panel. The focus of this research is to acknowledge the suitability of Kenaf fibres as raw material for floor panel. The evaluated floor panel samples consist of high density fibreboard as a core of floor panel and resin impregnated paper as lamination. The core was made up from Kenaf (Hibiscus cannabinus) bast fibres that were used to fabricate dry-formed fibreboard at three different board densities (850, 960 and 1000 kg/mʒ) with the thickness of 8mm and 12mm for each board. Bending modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA) and thickness swelling (TS) were measured for each panel in accordance to BS EN standard. The overall result showed increasing density and thickness increased were MOE, MOR, TS and WA. Density and thickness were significantly affecting all the panels’ properties except for MOR, TS and WA.

Abstract: The southwest region of Goiás is a major grain producer in the country, with emphasis on soybeans. It is protected by a pellicle grain into a legume. After its separation, the film is eventually discarded or used as animal feed. One alternative is the production of particleboards, considering lignocellulosic material, which could add value to this raw material. In this sense, the objective of this study was to evaluate the dimensional stability of particleboards produced with soybean residue, comparing them with eucalyptus panels. The particleboard was made with a nominal density of 0.55 g/cm³, and 12% of urea-formaldehyde adhesive were used, based on their content of resin solids and pressing cycle of 3.92 MPa, 180oC for 15 minutes. Three panels were produced by treating. The assessment of dimensional stability was made by measuring their density, water absorption and thickness swelling after immersion for 2 and 24 hours. Based on the results, it can be seen that, statistically, the panels had equal densities, an average value of 0.52 g/cm³. It is noted that the panels produced with a soy film had water absorption values of 2 to 24 hours, and thickness swelling in 24 hours, in comparison with the upper eucalyptus. For thickness swelling after 2 hours, no statistically significant difference between the tested materials was observed.

Abstract: The southwest region of the state of Goiás stands out for agriculture, especially the production of grain and sugarcane. This high agricultural production has a result of generation of agroindustrial waste and it has a high potential to be exploited for particleboard manufacturing. In this context, the objective of this study was to evaluate the use of sugarcane leaves in the production of particleboards, compared to eucalyptus panels, through the evaluation of their physical properties. Three panels were made with 100% sugarcane leaves, and three with eucalyptus wood were produced. They were produced with a nominal density of 0.60 g/cm3. 12% urea-formaldehyde adhesives were applied based on their resin solid content. The used pressing cycle was: pressure of 4.00 MPa, temperature of 180°C and time of 15 minutes. After production, the same properties were evaluated on their water absorption and thickness swelling after 2 and 24 hours of immersion. A randomized design was used, and the averages were compared by the Scott-Knott test at 5% significance. Based on these results, it can be seen that panels produced with sugarcane leaves exhibited higher values for physical properties than eucalyptus panels.Keywords: Thickness swelling, waste ,water absorption.

Abstract: In general, wood-polymer composites are vulnerable to weathering factors such as UV radiation, moisture, freeze-thaw action. Weathering can cause discoloration, chalking, dimensional change, and loss of mechanical properties of wood-polymer composites. This comparative study was focused on weatherability of wood–polypropylene composites made with and without pigments. Two types of inorganic pigments were applied: carbon black master-batch and synthetic iron oxide. Wood-polypropylene composite made without pigment was used as a reference. Also, composites prepared with addition of wollastonite were tested. The composite samples were exposed to outdoor weathering and in a parallel the accelerated UV weathering was conducted in xenon weathering chamber for the 2000 hours. The colour change was estimated by spectrophotometric method, and the change of Charpy impact strength after weathering was determined. The surface morphology was studied with scanning electron microscopy (SEM). The addition of pigments decreased the lightness of non-weathered composites. The change of lightness and total colour change of weathered composites were affected a lot by type of pigment and method of weathering. As, expected wood-polypropylene composite made with carbon black showed the best results in colour stability of composites exposed to weathering. SEM showed that accelerated weathering in the xenon chamber caused more significant changes in the morphology of the polymer surface layer of the composites than outdoor weathering. Charpy impact strength of all studied composites was found to retain after 2000 hours of outdoor weathering, although accelerated weathering caused significant reduction of Charpy impact strength of these composites.

Abstract: Both basalt fiber and mineral glass are water insulation materials, which are used to improve the permeability of engineered wood composite panels in this study. The contents of water resistant agent in wood composite panels are 0%,5%,10%,15%,20%,25%, respectively. It was found that the minimum thickness swelling was 2.55%, when the mineral glass content was 15%; the minimum thickness swelling was 5.09%, when the basalt fiber content was 5%. Both water insulation materials can reduce the water absorption, but mineral glass powder is more powerful.

Abstract: In this paper, the bamboo-poplar composite oriented strand board (OSB) with different hybrid ratios were aged under the standard of ASTM D1037 to evaluate its weathering performances. The thickness swelling (TS), water absorption, modulus of rapture in perpendicular direction (MOR_⊥), modulus of elasticity in perpendicular direction (MOE_⊥) and internal bonding (IB) of specimens were tested. The results showed that the reduction rate of TS ranged from 21% to 69%, which increased with the poplar ratio increasing; the growth multiple of 24h water absorption of bamboo-poplar composite OSB were at the similar level, the values of which were much smaller than that of the pure bamboo or poplar OSB; the maximum and minimum retention rate of MOR_⊥ and MOE_⊥ belonged to pure bamboo and poplar OSB respectively, retention rate of MOR_⊥ of the bamboo-poplar composite OSB rose with the increment of poplar ratio, while retention rate of MOE_⊥ and IB of bamboo-poplar composite OSB were similar and the hybrid ratio 2.5:7.5(bamboo: poplar) obtained the maximum IB retention rate of 16%. Through detailed comparison, the bamboo-poplar composite OSB with the hybrid ratio 2.5:7.5 performed the best after aging.

Abstract: Moisture absorption is a very important factor in polymers and composite materials used for hull manufacture and stability in marine environment. High water absorption of the material will affects the mechanical properties and stability in composite. This research is carried out to study the feasibility of the gravity effects on curing position of the laminated composite structures to enhance the curing space needed. Vertical cured laminate having almost similar properties with common horizontal cured laminate able to save much space in composite industry. Horizontal cured laminates filled up spaces in which SMI lack of. Polyesters and E-glass fibers were used as the raw material in this research. Vacuum bagging technique was used to suck out the excess resin during lay-up to avoid any voids and air inside laminate and cured at different angle position in room temperature for 24 hours. Seven samples of laminated composite were fabricated and cut into specific dimension in accordance to ASTM standard. This paper will discuss about the investigation on the water absorption and thickness swelling of the thermosetting laminated composite by curing the laminate at different angle using vacuum bagging technique. From the testing, SN6 and SN7 shows to have good water resistant in physical properties.

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.