• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.3
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• pp.53-58
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• 2008

Wood composite, could generally be made from very fine wood powder(<150 mesh) because more large size of wood particle had much less plasticity compared of polymer. To make more high plasticity of relatively large size of wood particle, wood particles were chemically modified with some reagent for acetylation and esterification, etc. WPC(wood plastic composite) was prepared with chemically modified wood particles and the mechanical properties of WPC were evaluated. WPC of esterified wood with maleic anhydride shows the highest level in tensile strength and breaking elongation.

• Composites Research
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• v.19 no.6
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• pp.38-42
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• 2006

Wood Plastic Composite(WPC) has been introduced as a new constructional material in Europe and North America. The maintenance-free durability against weather was accepted by customers and the environment-friendly merits ignited the abrupt increase of market size. Domestic major companies have kicked off the WPC business at the market of outdoor constructional materials. Due to the high contents of natural wood fiber, the production equipments should be modified to remove the moisture, to prevent thermal degradation and to promote output rates. Materials including functional fillers play a critical role in rheological properties, which affects the physical and mechanical properties of the last products. More research might be performed for synergy effects combined by various academic fields from mechanical and chemical engineering to polymer process and material science.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.3
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• pp.59-64
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• 2008

The mechanical properties of WPC(wood plastic composite) should effected with the size of wood particle size and also characteristics of wood particles. In this paper, WPC were prepared with various size of wood particles and coupling agent and the mechanical properties were evaluated. The smaller size of wood particle were used for WPC, the higher properties of WPC in tensile strength and breaking elongation were obtained. The smaller amount of wood particle were used for WPC, the higher properties of WPC in tensile strength and breaking elongation were obtained.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.15-22
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• 1999

Polymeric meterials that are used for noise and vibration damper in wood/polymer/wood sandwich composites, must have a high loss factor(tan ${\delta}$), and at the same time the storage modulus(E) of $5{\times}10^7$ to $10^9$ dyne/$cm^2$ must withstand over a wide temperature and frequency ranges. In this study, the series of epoxy resinlpolyacrylate interpenetrating polymer networks(IPNs) were synthesized by simultaneous polymerization. Their dynamic tensile properties were measured at 110Hz using Rheovibron instrument. Composite damping factor(tan ${\delta}_c$) and dynamic bending modulus($E_c,\;E_^{\prime\prime}c$) of wood/polymer/wood sandwich composites were measured at 110Hz using a Rheovibron in bending mode of vibration. These dynamic tensile studies indicated that cured epoxy resin/polyacrylates IPNs were semicompatible in the sense that both the shifting of T($E^{\prime\prime}_{max}$) or T(tan ${\delta}_{max}$) and the broadening of glass transition temperature range were observed. Especially, the cured Epikote871/P(n-BMA) IPNs of composition 70/30 to 50/50 showed a relatively high tan a and appropriate E' value over a wide temperature range; consequently the tan a e curves of wood/IPNs/wood sandwich composites was broadened over a wide temperature range.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.145-156
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• 2020

There are separate merits and demerits to wood and steel. The combination of wood and steel as a compound section is able to improve the properties of both and ultimately increase their final bearing capacity. The composite cross-section made of steel and wood has higher hardness while showing more ductility and the local buckling of steel is delayed or completely prevented. The purpose of this study is to investigate the behavior of composite columns enclosed in wooden logs and the hollow sections of steel that will be examined in a laboratory environment under the axial load to determine the final bearing capacity and sample deformation. In terms of methodology, steel sheet and carbon fiber reinforced polymer sheet (FRP) are tested to construct hollow rectangular sections and reinforce timber. Besides, the method of connecting hollow sections and timber including glue and screw has been also investigated. As a result, timber lumber enclosed with carbon fiber-reinforced polymer sheets in which fibers are horizontally located at 90° are more resistant with better ductility.

• Composites Research
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• v.20 no.2
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• pp.32-38
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• 2007

Natural fibers can refer to all types of fibres only produced by nature. Their lengths vary from particles to long strands. Natural fibers are categorized roughly by six types, depending on the types of sources; base, leaf, seed, grasses, fruit and wood. Of these fibers, jute, flax, sisal and ramie are the most commonly used as reinforced materials in preparing polymer composites. In development and improvement of these composites, many studies have been implemented to overcome the drawbacks such as incompatibility, moisture problems and so on. The range of industry sectors of natural fiber-reinforced polymer composites becomes more extensive gradually and many of the companies all over the world are engaged in fabrications or applications. This paper mainly discussed the recent status of the domestic/overseas market and research issues of natural fiber-reinforced polymer composites. We made an exception of wood-polymer composites market which have played a great role because they had been often dealt with.

• Polymer(Korea)
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• v.39 no.1
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• pp.46-55
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• 2015

There is a limit for deforestation in order to keep the environmental cycle undisturbed. The heart of the paper is to replace the wood to a maximum extent to obtain a sustainable environment. This research aims at new natural composites in which treated hemp fiber used as reinforcement, synthetic cellulose used as particulate to improve the adhesion between matrix - fiber interface and Epoxy LY556 acted as matrix fabricated by hand layup technique. The density, water absorption, tensile properties, impact strength, hardness, flexural properties and compressive properties have been evaluated under ASTM standards and compare the results with existing materials such as wood, aluminium, etc., The composite hemp fiber reinforced polymer (HFRP) could be exploited as an effective replacement for wood and it would be suitable for automotive applications by comparing results.

• Resources Recycling
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• v.8 no.4
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• pp.57-63
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• 1999

Wood-Polymer Composites (WPC) m s prepared irom recycled films of agricullural use and wood wastes, and LLDPE and neal PE resin mlxlurr war also utilized in order to cornpiue the praperlies. Molc~ca nhydride (MA) and dicumyl peroxide were used as an adheslon pmmoler and an il~lliatotor~, .espcmivelyT. ensile prapenies of W Cw zrc measured via lenslle test as a funclieu of woad lille~m d MA contmt, and rractu1.e surface was also mvestigaled wilh SEM. As the content of wwd tiller mcreased, clongauon deneased bul modulus increased However, tensile slrength OI WPC increased only when MA war used, and 1 wt.% of MA may be hgh enough to increase the tensile properties. The tensilc ptopcrlies af WPC prepwed from recycled PE films were &nost same as thosc of neal PE resin mixture.

• Journal of the Korean Wood Science and Technology
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• v.51 no.6
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• pp.526-541
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• 2023

Wooden structures are widely used, particularly in earthquake zones, owing to their light weight, ease of application, and resistance to the external environment. In this study, we aimed to improve the mechanical properties of laminated timber beams using novel hybrid systems [carbon-fiber-reinforced polymer (CFRP) and wire rope]. Within the scope of this study, it is expected that using wood, which is an environmentally friendly and sustainable building element, will be more economical and safe than the reinforced concrete and steel elements currently used to pass through wide openings. The structural behavior of the hybrid-reinforced laminated timber beams was determined under the loading system. The experimental findings showed that the highest increase in the values of laminated beams reinforced with steel ropes was obtained with the 2N reinforcement, with a maximum load of 38 kN and a displacement of 137 mm. Thus, a load increase of 168% and displacement increase of 275% compared with the reference sample were obtained. Compared with the reference sample, a load increase of 92% and a displacement increase of 14% were obtained. Carbon fabrics placed between the layers with fiber-reinforced polymer (FRP) prevented crack development and provided significant interlayer connections. Consequently, the fabrics placed between the laminated wooden beams with the innovative reinforcement system will not disrupt the aesthetics or reduce the effect of earthquake forces, and significant reductions can be achieved in these sections.

• Polymer(Korea)
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• v.38 no.2
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• pp.129-137
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• 2014

In this study, the melt-mixing condition was optimized first to maximize the physical properties of a wood plastic composite (WPC) with recycled polypropylene (PP) and the effects of recycled PP content on the physical properties of the WPC were investigated. Mechanical properties of the WPC were measured by UTM and an izod impact tester and thermal properties were investigated by DSC, TGA and DMA. Fracture surfaces of the WPC were investigated by SEM. The optimized mixing condition of WPC with 50 wt% recycled PP of total PP was melt-mixing at $170^{\circ}C$ for 15 min at 60 rpm. With increasing the content of the recycled PP, the water absorption characteristics of the WPC increased and the thermal and mechanical properties decreased. However, the following was concluded from the analysis of all the physical properties; it was possible adding the recycled PP up to 50 wt% of total PP without a significant decrease in the performance of the WPC.