• Polymer(Korea)
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• v.26 no.2
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• pp.260-269
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• 2002

The fire resistance of particulate polypropylene composite systems were investigated by using various reinforced particles such as zeolite, talc, $CaCO_3$ particles. In this study, The effect of particle size on the thermal properties of composite and the effect of reinforced particles on the fire resistance were studied. The inorganic reinforced particles used in this study were recycled zeolite(average particle diameter=85.34 $mu extrm{m}$), $CaCO_3$ (33.93 $mu extrm{m}$), and talc (18.51 $mu extrm{m}$). The fire resistance of composite systems was thoroughly examined by measuring limited oxygen index (LOI, ASTM D2863) and cone calorimetry (ASTM E1354, ISO 5660). Thermal stability of composite systems was thoroughly examined by measuring TGA. The flame retardants (DBDPO) and reinforced particles reduce the maximum heat release rate (M-HRR) in the order of Talc > $CaCO_3$ > recycled Zeolite. Comparing the cone calorimetry experimental results of the particle reinforced polymer composite system exhibited twice higher efficiency than DBDPO in polypropylene systems, and the LOI also showed similar trends to the cone calorimetry experiments. The optical and scanning electron microscopy techniques were used to investigate the composites ash layer and the core fracture surfaces in the burning process. The reinforcing inorganic particles seemed to accumulate at the surface of ash layer, and subsequently intercept the oxygen transport and heat transfer into the core area.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.4
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• pp.317-326
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• 2022

This research performed single fiber pull-out test to evaluate the effect between fineness modulus of cement composites and the fiber bond performance (bond strength and pull-out energy). A synthetic fiber (polypropylene) and a steel fiber (hooked ends type) were inserted in the middle of dog bone shape specimens which were designed with fine aggregates of F. M. 1.96, 2.69, 3.43. The experiment results showed bond strength and pullout energy of synthetic fiber are improved as fineness modulus of cement composites increases. It is considered that the frictional resistance between synthetic fiber and cement composite increases as fineness modulus of cement composite increases and consume more energy while pull out the fiber from cement composite. However bond performance of steel fiber which resist pull out by mechanical behavior is less effected on fineness modulus of cement composite. It is considered that the mechanical fixedness of hooked ends exerts a greater effect on the pullout resistance than the frictional resistance between the cement composite and the steel fiber so F. M. of fine aggregate has a relatively small effect on the pullout resistance with the steel fiber.

• Geomechanics and Engineering
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• v.5 no.2
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• pp.87-97
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• 2013

In this paper, a novel fibrous material known as axially reinforced braided composite rods (BCRs) have been developed for reinforcement of soils. These innovative materials consist of an axial reinforcement system, comprised of longitudinally oriented core fibres, which is responsible for mechanical performance and, a braided cover, which gives a ribbed surface texture for better interfacial interactions with soils. BCRs were produced using both thermosetting (unsaturated polyester) and thermoplastic (polypropylene) matrices and synthetic (carbon, glass, HT polyethylene), as well as natural (sisal) core fibres. BCRs were characterized for tensile properties and the influence of core fibres was studied. Moreover, BCRs containing carbon fibre in the core composition were characterized for piezoresistivity and strain sensing properties under flexural deformation. According to the experimental results, the developed braided composites showed tailorable and wide range of mechanical properties, depending on the core fibres and exhibited very good strain sensing behavior.

• Computers and Concrete
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• v.21 no.3
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• pp.231-237
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• 2018

A strain-hardening highly ductile composite based on an alkali-activated slag binder and synthetic fibers is a promising construction material due to its excellent tensile behavior and owing to the ecofriendly characteristics of its binder. This study investigated the effect of different types of synthetic fibers and water-to-binder ratios on the compressive strength and tensile behavior of slag-based cementless composites. Alkali-activated slag was used as a binder and water-to-binder ratios of 0.35, 0.45, and 0.55 were considered. Three types of fibers, polypropylene fiber, polyethylene (PE) fiber, and polyparaphenylene-benzobisethiazole (PBO) fiber, were used as reinforcing fibers, and compression and uniaxial tension tests were performed. The test results showed that the PE fiber series composites exhibited superior tensile behavior in terms of the tensile strain capacity and crack patterns while PBO fiber series composites had high tensile strength levels and tight crack widths and spacing distances.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.199-210
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• 2000

복합재료의 성형 공정 중 하나인 Filament Winding 공정에 열가소성 기지재료인 폴리프로필렌(Polypropylene)과 강화섬유인 유리섬유로 이루어진 Commingled Yarn 을 이용한 연구를 수행하였다. 함침 과정을 해석하기 위한 계산모델을 제시하였다. 그리고 위의 모델링을 해석하는 데 필요한 복합재료 내의 온도 분포를 수치해석을 통해 계산하였고 실험을 통해 이를 검증하였다. 온도계산 결과를 함침도 예측에 이용하였다. 모델링을 통해 Filament Winding 공정의 주요 공정 변수를 찾아내었고 제시한 모델을 검증하기 위해 직접 Filament Winding 실험 장치를 제작하여 제품을 생산하고 모델과 비교하였다. 제작된 시편으로부터 함침도를 계산하는 방법을 제시하였다. 그 결과 함침도에 관해서 실험 결과가 모델과 그 경향이 뚜렷이 일치함을 확인하였다.

• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.79-87
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• 2006

Value-added utilization of the disposed ash trees due to the infestation by Emerald Ash Borer (EAB) was explored by converting them into particleboards (PBs) and wood-plastic composites (WPCs). The experimental result showed that PB panels could be successfully manufactured from the ash wood but compaction ratio need to be higher than 1.3 in order to meet the standard requirements listed by American National Standards Institute (ANSI). Ash wood plastic composites with high density polyethylene (HDPE) and polypropylene (PP) were also prepared with additives by extrusion. Physical and mechanical properties of ash wood plastic composite compared favorably to those made of pine and maple.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.181-184
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• 2005

Experimental results on lap splice performance of high performance fiber reinforced cementitious composite(HPFRCC) with fiber types under repeated loading are reported. Fiber types were polypropylene(PP), polyethylene(PE) and hybrid fiber[polyethylene fiber+steel cord(PE+SC)]. The development length($l_d$) was calculated according to the relevant ACI code requirements for reinforcing bars in concrete. The current experimental results demonstrated clearly that the use of fibers in cementitious matrixes increases significantly the splice strength of reinforcing bars in tension. Also, the presence of fibers increased the number of cracks formed around the spliced bars.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.381-384
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• 2006

Fibers are increasingly being used for the reinforcement of cementitious matrix to enhance the toughness and energy absorption capacity and to reduce the cracking sensitivity of the matrix. In the past decade, high performance fiber reinforced cementitious composite(HPFRCC) have evolved with intensified research. HPFRCC for structural applications has been developed under the performance driven design approach. It is the aim of this study to obtain development of hybrid-HPFRCC using polypropylene fibers and polyethylene fibers. It was targeted the requirement of economical mixing and application to structure member.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.342-345
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• 2006

The properties of reinforcing fiber, as tensile strength, aspect ratio and elastic modulus, have great effect on the fracture behavior of HPFRCC(High performance fiber-reinforced cementitious composite). Acoustic emission(AE) method was used to evaluate the characteristics of fracture process and the micro-failure mechanism of HPFRCC. For these purposes, three kinds of fibers were used : PP(Polypropylene), PE(Polyethylene), SC(Steel cord). In this study, the AE characteristics of HPFRCC with different fiber type(PE.15, PP2.0, SC0.75+PE0.75) distributions under four-point-bending were studied. The result show that the AE technique is a valuable tool to study the failure mechanism of HPFRCC.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.213-217
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• 2003

In this paper, we studied electric Insulation characteristics of synthetic Laminated Polypropylene Paper (LPP) in liquid nitrogen (L$N_2$) for the application to high temperature super-conducting (HTS) cable. And, we selected the insulation paper/L$N_2$composite insulation type for the electric insulation design of a HTS cable. Furthermore, we compared the breakdown characteristics of the butt gap and bended mini-model cable that comes into being in this kind of cryogenic insulation type. It is necessary to understand the winding parameter of insulation paper/L$N_2$composite insulation.