• The Korean Journal of Rheology
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• v.3 no.2
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• pp.175-185
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• 1991

Sodium octylbenzenesulfonate(SOBS)와 sodium dodecylbenzenesulfonate(SDBS)를 폴리프로필렌(PP) 용융액에 각각 균일하게 서로 다른 함량으로 섞어 넣은 후에 용융압착법 으로 PP 필름을 제조하였다. 저장 점성도(η＇) 저장탄성률(G＇) 및 손실 탄성률(G＂)을 진 동식 레오미터를 사용하여 170~195$^{\circ}C$에서 측정하였다. 실험온도 범위내에서 첨가제를 함유 한 PP와 순PPrks에 Cole-Cole 플롯(G＇에 대한 G＂의 log-log 플롯)에는 차이가 없었다. 그러나 광범위한 전단속도에서 SOBS의 첨가량이 8%를 넘어서면서 η＇과 G＇은 증가하였 다. 이러한 현상은 PP 중에서의 첨가제의 응집효과로 설명되었으며 이것은 SOBS와 SDBS 를 함유하는 PP 필름의 시차 주사열량법 및 주사전자 현미경 관찰결과로 확인되었다. SDBS를 8% 미만 함유하는 PP로부터 섬유의 용융방사가 가능하였으나 SDBS3% 이상 함 유PP 방사섬유는 연신 과정중에 섬유의 절단이 이따금 일어났다. PP 기질내에 있어서의 SDBS의 뜨거운 물에대한 견뢰성을 SDBS와 C. I. Basic blue 41사이의 이온결합 형성 거동 에 바탕을 두어 가시분광법에 의하여 검토하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.745-748
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• 2006

This study investigates the fundamental properties and examines spalling appearances and residual compressive strength of high strength concrete containing hybrid organic fibers subjected to fire. Test showed that overall, an increase of fiber content decreased the fluidity of concrete, but specimens containing polyvinyl alcoho(PVA)+polypropylene(PP) fiber and nylon(NY)+PP fiber had improved flow. In addition, the air content of all specimens was properly ranged in target value, regardless of fiber content. As for the spalling properties when completed the fire test, control concrete exhibited spalling occurrence due to sudden elevated temperature. However, specimens containing more than 0.1 vol% of PP fiber prevented the spalling, while specimens containing PP+CL and PVA+PP fiber can protected from fire in more than 0.15vol% of the fiber content. Importantly, a specimen containing only 0.05vol% of NY+PP showed the favorable spalling resistance performance.

• Resources Recycling
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• v.23 no.1
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• pp.70-79
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• 2014

In this study, waste polypropylene and waste ground rubber tire(WGRT) composites were prepared by using a modular intermeshing co-rotating twin screw extruder. The effect of three main factors such as WGRT contents, particle size, compatibilizers on the properties of waste PP/WGRT composites was extensively investigated. Tensile strength of the composites was decreased with an increase in WGRT contents, whereas elongation at break and impact strength were increased. The tensile strength, elongation at break and impact strength of the composites with the smaller size of the WGRT were more enhanced. Addition of PP-g-MA into waste PP/WGRT composites exhibited better tensile strength. However, elongation at break and impact strength were slightly decreased with increasing of PP-g-MA. On the other hand, tensile strength, impact strength and elongation at break of the composites were increased by adding the EPDM-g-MA and SEBS-g-MA. Especially, elongation at break was significantly increased compared to the composite with PP-g-MA.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.106-111
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• 2008

Polypropylene (PP)/corn starch master batch (starch-MB)/silicate composites with different corn starch compositions of 10, 20, 30, 40 and 50 were prepared by melt compounding at $200^{\circ}C$, using lab scale Brabender mixer. The content of silicate was fixed at 5 wt%. The composition of starch-MB in composites was confirmed by the existence of hydroxy group and peak intensity in fourier-transform-infrared (FT-IR) spectrum. The thermal properties of the PP/starch-MB/silicate composites were investigated by differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). There was no district change in melting temperature, and TGA curve indicates a decrease in degradation temperature with the increase of starch-MB content. The silicate dispersion of the composites was measured by X-ray diffraction (XRD) and transmission electron microscope (TEM). The degree of silicate dispersion in PP/starch-MB/silicate composites depended on the content of starch-MB. There was detectable change in d-spacing and peak intensity of the composite when the content of starch-MB was higher than 20 wt%. The rheological behavior of the composites was explained by both shear thinning effect and elastic property with the starch-MB amount. These effects were remarkable when the content of starch-MB was higher than 20 wt%. These were confirmed by an oscillatory viscometer at $200^{\circ}C$.

• Elastomers and Composites
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• v.35 no.1
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• pp.46-52
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• 2000

Miscibility improvement between polypropylene(PP) and ethylene-propylene-diene-terpolymer (EPDM) was studied by introducing specific interaction into both polymers. PP was modified by grafting maleic anhydride(MAH) onto backbone, leading to MAH-grafted PP(PP-g-MAH). Sulfonated EPDM ionomer neutralized with bivalent zinc cation(ZnSEPDM) was used as one component. The blends of PP-g-MAH and ZnSEPDM were prepared at $200^{\circ}C$ in Brabender Roller Mixer. Fourier transform-infrared(FT-IR) spectroscopic and dynamic mechanical studies have been performed to investigate the miscibility. FT-IR spectral peak corresponding to carbonyl group in PP-g-MAH and that to sulfonate group in ZnSEPDM were shifted to lower and higher frequency with increasing ZnSEPDM content, respectively, in the blends. Glass transition temperature of ZnSEPDM was increased up to 70wt.% of ZnSEPDM, and again decreased above 70wt.%. It can be concluded from the shift of FT-IR characteristic peaks and the changes of glass transition temperatures that the miscibility between PP and EPDM was improved via introducing specific interaction, i.e., dipole-ion interaction.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.55-62
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• 2005

This study was conducted to evaluate the application of a bio-composite made by the addition recycled fiber board flour as filler. Recycled fiber board (high density fiber board, HDF) flour was added to polyolefin polymer low density polyethylene (LDPE) and polypropylene (PP) for the preparation of bio-composite materials. The mechanical properties and processability of the recycled HDF flour filled LDPE and recycled HDF flour filled PP bio-composites were then measured and compared to those of wood flour (WF) and rice-husk flour (RHF) filled LDPE and PP bio-composites, respectively. The tensile and impact strengths of the recycled HDF flour filled LDPE and PP bio-composites had similar mechanical properties to those of the WF and RHF filled LDPE and PP bio-composites. To measure the processability, torques of the bio-composites were also measured. The torques of the HDF flour filled LDPE and PP bio-composites were lower than those of the WF and RHF filled polyolefin (PP and LDPE) bio-composites with a filler loading of 30 wt.%. This result showed definite processability, which was not related with the distribution of the particle size of the material added. The recycled fiber board flour filled bio-composites showed applicability as substitutes for the bio-composites currently used in the bio-composites industry.

• Journal of the Korean Wood Science and Technology
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• v.34 no.2
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• pp.10-21
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• 2006

Recycled polypropylene (RPP) - Wood Saw Dust (WSD) composites with and without acetylation of filler were produced at different filler loading (15%, 25%, 35% and 45% w/w) and filler size (300, 212 and $100{\mu}m$). The RPP-WSD was compounded using a Haake Rheodrive 500 twin screw compounder at $190^{\circ}C$ at 8 MPa for 30 minutes. The mechanical properties and water absorption properties of modified and unmodified WSD-PP composites were investigated. Acetylation of WSD improved the mechanical and water absorption characteristic of composites. The decrease of filler size (300 to $100{\mu}m$) of the unmodified and acetylated WSD showed increase of tensile strength and impact properties. The composites exhibited higher tensile modulus properties as the filler loading increased (15% to 45%). However tensile strength, elongation at break and impact strength showed the opposite phenomenon. Water absorption increased as the mesh number and filler loading increased. With acetylation, lower moisture absorption was observed as compared to unmodified WSD. The failure mechanism from impact fracture of the filler-matrix interface with and without acetylation was analyzed using Scanning Electron Microscope (SEM).

• Fibers and Polymers
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• v.3 no.1
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• pp.38-42
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• 2002

Polypropylene filaments were spun from a mixture of PP chips of two different Melt Flow Index (MFI) (3 MFI and 35 MFI). A significant difference was observed in the melting characteristics of the resultant filaments from either of the individual components as observed from the DSC. The main difference being in the degree of melting achieved at any temperature in the initial stages of the melting range, which was found to be higher in case of the filaments spun from the b]end. These filaments were then thermally bonded using silicon oil bath and heated roller method. Subsequently the bond strength of the filaments was measured on the Instron Tensile Tester using the loop technique. The values of the world strengths obtained from the blend were compared with those made from the individual component. It was found that the bond strength of the bonds obtained from the blended filament at a given temperature was higher than that of the bonds made from the filaments of either of the individual components, which is also suggested by the DSC curves. The difference in the bond strength was found to be as high as 25% in case of the blend with 60:40 composition ratios of the 3 MFI and 35 MFI components respectively.

• Elastomers and Composites
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• v.46 no.4
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• pp.318-323
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• 2011

To recycle the waste tire rubber powder, rubber powder composite for waterproof sheet was prepared, and analyzed the effect of the kind of resin and the amount of crosslinking agent on the mechanical property of the composites. The elongation-at-break of the PE composite increased more than 3 times as EPDM was added into rubber composites. As the content of the crosslinking agent increased, the tensile strength of composite increased as well. When recycled polypropylene was used, the increase in composite's tensile strength was more than 3 times. Therefore to use the recycled PP in composite is more effective rather than PP in term mechanical properties.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.125-128
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• 2005

The dispersion of carbon nanofiber (CNF) was carried out by solution blending, mechanical mixing, and sonication. CNFs at levels of 5-50% fiber weight content were mixed with polypropylene (PP) powder, and then were melt-mixed using a twin-screw extruder. For the further alignment of fibers, extruded rods were stacked uni-directionally in the mold cavity for the compression molding. For the evaluation of mechanical properties of nanocomposites, tension, in-plane shear, and flexural tests were conducted. CNF/PP composites clearly showed reinforcing effect in the longitudinal direction. The tensile modulus and strength have improved by 100% and 40%, respectively for 50 % fiber weight content, and the flexural modulus and strength have increased by 120% and 25%, respectively for the same fiber weight content. The shear modulus showed 65% increase, but the strength dropped sharply by 40%. However, the property enhancement was not significant due to the poor adhesion between fiber and matrix. In the transverse direction, the tensile, flexural, and shear strength decreased as more fibers were added.