• 수산해양기술연구
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• 제41권1호
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• pp.78-84
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• 2005

The main goal of this work is to study the effects of temperature and volume fraction of fiber on the Charpy impact test with GF/PP composites. The critical fracture energy and failure mechanisms of GF/PP composites are investigated in the temperature range of 60^{\circ}C$ to -50^{\circ}C$ by impact test. The critical fracture energy increased as the fiber volume fraction ratio increased. The critical fracture energy shows a maximum at ambient temperature and it tends to decreases as temperature goes up or goes down. Major failure mechanisms can be classified such as fiber matrix debonding, fiber pull-out and/or delamination and matrix deformation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.124-125
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• 2017

In this study, the spalling properties of Polypropylene reinforced concrete were evaluated by the restrained ring-type test. As a result of the experiment with the fiber mixture ratio set at 0, 0.15 vol.%, The PP fiber reinforced specimen showed lower water vapor pressure as a whole than the Plain specimen, but the restraint stress was measured to be higher. This is thought to be due to the fact that higher thermal stresses were applied in the PP fiber reinforced test specimen.

• 한국구조물진단유지관리공학회 논문집
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• 제10권2호
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• pp.83-90
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• 2006

고강도 콘크리트는 구조적인 장점에도 불구하고 화재 시 폭렬과 함께 취성적인 파괴를 나타내는 단점으로 인하여 내화설계 시 주의하여 사용하여야 한다. 고강도 콘크리트의 폭렬제어를 위하여 폴리프로필렌 섬유(PP섬유)의 혼입이 가장 효율적인 것으로 여러 연구결과를 통하여 보고 되었으나, 이들은 대부분 콘크리트 공시체를 대상으로 한 내화실험의 결과로서 최적의 PP섬유 혼입량에 대한 부재수준의 연구는 매우 부족한 실정이다. 본 연구에서는 고강도 콘크리트 기둥의 내화설계를 위한 최적의 PP섬유 혼입량을 제시하기 위하여 콘크리트 강도와 PP섬유의 혼입량을 변수로 하는 기둥부재의 내화실험 및 잔존강도 실험을 수행하였으며, 실험결과 콘크리트 강도가 증가 할수록 기둥 실험체의 잔존 축강도비는 증가하였으며, PP섬유 혼입량을 0%에서 0.2%까지 증가 시킬수록 기둥의 잔존 축강도비가 증가하는 것으로 나타났다. 따라서 최적의 PP섬유 혼입량으로서 0.2%가 적절할 것으로 판단된다.

• Membrane and Water Treatment
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• 제10권2호
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• pp.155-163
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• 2019

The roles of polypropylene (PP) beads and pH on membrane fouling and treatment efficiency were investigated in a hybrid advanced water treatment process of tubular carbon fiber membranes (ultrafiltration (UF) or microfiltration (MF)) and PP beads. The synthetic feed including humic acid and kaolin flowed inside the membrane, and the permeated contacted the PP beads fluidized in the space between the membrane and the module with UV irradiation and periodic water back-flushing. In the hybrid process of UF ($0.05{\mu}m$) and PP beads, final resistance of membrane fouling ($R_f$) after 180 min increased as PP beads increased. The turbidity treatment efficiency was the maximum at 30 g/L; however, that of dissolved organic matters (DOM) showed the highest at PP beads 50 g/L. The $R_f$ strengthened as pH of feed increased. It means that the membrane fouling could be inhibited at low alkali condition. The treatment efficiency of turbidity was almost constant independent of pH; however, that of DOM showed the maximum at pH 5. For MF ($0.1{\mu}m$), the final $R_f$ was the minimum at PP beads 40 g/L. The treatment efficiencies of turbidity and DOM were the maximum at PP beads 10 g/L.

• 수산해양기술연구
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• 제40권2호
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• pp.161-165
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• 2004

The main goal of this work is to study the effect of glass fiber volume fraction on the result of tensile test with respect to glass fiber/polypropylene(GF/PP) composites. The tensile test and failure mechanisms of GF/PP composites were investigated in the fiber volume fraction range from 10% to 30%. The tensile strength and the fracture strength increased with the increasing of the fiber volume fraction in the tested range. Fiber pull-out and debonding of this composites increased with the fiber volume fraction in thc tested range. The major failure mechanisms were classified into the debonding, the fiber pull out, the delamination and the matrix deformation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.419-420
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• 2010

고강도 콘크리트는 폭렬 발생을 제어하기 위하여 PP섬유와 나일론 섬유 등을 혼입하며, fiber cocktail로 PP섬유와 강섬유를 혼입한 형태도 많이 연구되어지고 있다. 본 연구에서는 Fiber-cocktail 내의 폴리프로필렌은 $1.5kg/m^3$, 강섬유는 각각 20, 30, $40kg/m^3$로 하여 시험체내의 온도를 살펴보았다. 실험결과 강섬유의 혼입이 증가하면서 콘크리트 내부 온도 및 철근의 온도가 낮아지는 것으로 나타나 강섬유는 고강도 콘크리트 화재 시 폭렬의 방지 및 온도상승 지연의 효과가 있는 것으로 나타났다.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.877-887
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• 2015

본 연구진은 사출성형 공정에서 적용되는 미지 시료 및 고점도의 복합소재 점도를 추정하기 위한 새로운 방법을 제시한 바 있다. 본 논문에서는 사출성형 금형 캐비티 내압을 측정하는 장치를 개발하였다. 이는 사출성형 공정 중의 금형 내를 흐르는 용융체의 압력을 실시간으로 측정하고, 이를 CAE 해석 결과로부터 모사된 압력과 비교함으로써 CAE D/B내의 점도 데이터의 정확성을 검증할 수 있게 한다. 본 연구에서 사용한 재료는 PP(Polypropylene), PP/LGF30%(Polypropylene과 long glass fiber 50% composite), PA66/LGF50%(Polyamide 6,6와 long glass fiber 50% composite) 이다. 여기서 PP와 PP장섬유복합재료는 이미 점도 데이터가 구축되어 있으나, PA66장섬유복합재료는 새롭게 개발한 재료로써 기존의 점도 데이터가 없기에 본 시스템을 이용해서 새로운 점도 곡선을 추정하였다. 그리고, 일반 점도 측정장치로 구한 점도 곡선과도 비교하였다. 한편, 이미 점도 데이터를 갖고 있는 경우인 PP는 신뢰성을 확인할 수 있었으나, PP/LGF50%의 경우는 높은 점도와 구조의 복잡성으로 인해 기존 점도 데이터의 개선이 필요하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.553-556
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• 2004

This paper is to investigate the spalling and fire endurance of high performance RC column member with PP fiber and lateral confinement of metal lath and non fire resistance removal type form. According to test results, combination of PP fiber and metal lath as well as use fire resistance non removal type form had favorable fire resistance by discharging internal vapour pressure and lateral confining. After fire endurance test, compressive strength decreased markedly caused by internal expansion pressure and crack. Residual strength of plain concrete was decreased to $22\%$. The use of PP fiber and lateral confinement of metal lath and non removal type form enhanced the residual strength above $40\%$. Especially, the combination of $0.1\%$ of PP fiber and lateral confinement with the level of 2.3T exhibited more than $51\%$ of residual strength. Therefore, to improve fire endurance and spalling resistance, the combination of $0.1\%$ of PP fiber and metal lath with 2.3T can be the proper measure.

• International Journal of Concrete Structures and Materials
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• 제9권4호
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• pp.475-486
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• 2015

Mode II fracture toughness ($K_{IIc}$) of fiber reinforced concrete (FRC) has been widely investigated under various patterns of test specimen geometries. Most of these studies were focused on single type fiber reinforced concrete. There is a lack in such studies for hybrid fiber reinforced concrete. In the current study, an experimental investigation of evaluating mode II fracture toughness ($K_{IIc}$) of hybrid fiber embedded in high strength concrete matrix has been reported. Three different types of fibers; namely steel (S), glass (G), and polypropylene (PP) fibers were mixed together in four hybridization patterns (S/G), (S/PP), (G/PP), (S/G/PP) with constant cumulative volume fraction ($V_f$) of 1.5 %. The concrete matrix properties were kept the same for all hybrid FRC patterns. In an attempt to estimate a fairly accepted value of fracture toughness $K_{IIc}$, four testing geometries and loading types are employed in this investigation. Three different ratios of notch depth to specimen width (a/w) 0.3, 0.4, and 0.5 were implemented in this study. Mode II fracture toughness of concrete $K_{IIc}$ was found to decrease with the increment of a/w ratio for all concretes and test geometries. Mode II fracture toughness $K_{IIc}$ was sensitive to the hybridization patterns of fiber. The (S/PP) hybridization pattern showed higher values than all other patterns, while the (S/G/PP) showed insignificant enhancement on mode II fracture toughness ($K_{IIc}$). The four point shear test set up reflected the lowest values of mode II fracture toughness $K_{IIc}$ of concrete. The non damage defect concept proved that, double edge notch prism test setup is the most reliable test to measure pure mode II of concrete.

• 한국염색가공학회지
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• 제10권5호
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• pp.13-18
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• 1998

Polypropylene-ethylene/vinyl acetate copolymer (PP-EVA) blends were prepared by mechanical blending using relatively semi-crystaline ethylene-vinyl acetate copolymer and polypropylene. In order to obtain dyeable PP fiber, PP-EVA blends were prepared using below 10wt.％ of EVA and formed a filament by the melt spinning method. The resultant fibers had tensile strengh of 2∼3g/d, elongation of 330∼600%, initial modulus of 22∼46g/d, and exhibited markedly improved dyeing property.