• Journal of the Korean Wood Science and Technology
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• 제34권2호
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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).

• 한국염색가공학회지
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• 제27권2호
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• pp.105-112
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• 2015

In order to detect gas phase strong acid on fabrics, a hexyl-substituted monoazo yellow dye, which was the modified form of a conventional pH-indicating dye, Methyl Yellow, was studied in view of acid-gas sensing properties and its fastness. The dye was printed on polypropylene non-wovens for protective coveralls and examined under various conditions of strong acid such as hydrochloric acid. The dye showed color change from yellow to red on exposure to gas phase hydrochloric acid as low concentration as 1~3 ppm very instantly. Considering reuse of the dye-printed non-wovens, the repeatability of color change was tested on the same sample for 50 repeats and 100 days. The acid-gas sensing function was maintained almost the same level of initial performance. The color fastness of the dye on polypropylene non-wovens was very good showing higher than ratings 4 except for 3~4 to rubbing under wet condition.

• 한국염색가공학회지
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• 제11권2호
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• pp.27-37
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• 1999

Polypropylene(PP) films were treated with plasma glow discharge to produce peroxy radicals on the surfaces. The peroxy radicals formed on the PP film surfaces were subsequently used for the graft polymerization of acrylic acid and acrylamide in an aqueous solution by heating, respectively. Introduction of acrylic acid and acrylamide on the PP film could be confirmed by the observation of carbonyl and primary amine absorptions based on carboxylic acid and amide, respectively. And introduction of functional group could be confirmed by weight analysis and ESCA. The water contact angle(90$^{\circ}$) of PP film was constant, irrespective of elapsed time, while plasma-treated and functional monomer-grafted PP films were slowly increased with elapsed time, showing the rearrangement of surface polar groups in air condition. The water contact angle$(90^\circ)$ of PP film was decreased by the plasma treatment$(56^\circ)$ and further decreased by the grafting of acrylic acid$(34^\circ)$ and acrylamide$(37^\circ)$, indicating increased hydrophilicity of the modified surfaces. The water contact angle of plasma-treated PP film increased a little as time elapsing. The half-life periods of surface voltage on acrylic acid-(31sec) and acrylamide-grafted PP(42sec) were significantly decreased when compared to those on PP(950sec) and plasma-treated PP film(241sec). In the experiments using acid, basic and disperse dyes, absorbance and $\Delta{E}$ values of functional monomer-grafted PP films were significantly increased than that of oxygen plasma-treated one.

• Transactions on Electrical and Electronic Materials
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• 제12권3호
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• pp.110-114
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• 2011

Polymeric films of high chemical stability and mechanical strength covered with a thin metallic film have been extensively used in various fields as electric and electronic materials. In this study, we have chosen polypropylene (PP) as the polymer due to its outstanding chemical resistance and good creep resistance. We coated thin nickel film on PP films by the electroless plating process. The surfaces of PP films were pre-treated and modified to increase the adhesion strength of metal layer on PP films, prior to the plating process, by an environment-friendly process with atmospheric plasma generated using dielectric barrier discharges in air. The surface morphologies of the PP films were observed before and after the surface modification process using a scanning electron microscope (SEM). The static contact angles were measured with deionized water droplets. The cross-sectional images of the PP films coated with thin metal film were taken with SEM to see the combined state between metallic and PP films. The adhesion strength of the metallic thin films on the PP films was confirmed by the thermal shock test and the cross-cutting and peel test. In conclusion, we made a composite material of metallic and polymeric films of high adhesion strength.

• 폴리머
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• 제32권1호
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• pp.7-12
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• 2008

폴리(에틸렌 테레프탈레이트) (PET) 섬유는 폴리프로필렌(PP)에 비해 높은 기계적 물성과 용융온도를 갖고있어 폴리프로필렌의 기계적 물성을 향상시키기 위한 섬유강화재료로 사용이 가능함을 확인하였다. 그러나 PP와 PET 섬유는 상용성이 부족하여 복합재료의 기계적 물성이 저하되었으며 PET 섬유의 구조적인 특성상 PP-g-MAH를 첨가하여도 효과가 부족하였다. 이러한 문제점을 해결하기 위해 NaOH 수용액으로 PET 섬유의 표면처리를 하여 PET 섬유의 표면에 친수성기를 도입하였으며 상용화제로서 PP-g-MAH를 첨가하여 기계적 물성이 우수한 PP/PET 섬유 복합재료를 제조하고 SEM과 IR의 결과와 물성의 거동을 상호 관련지었다.

• Elastomers and Composites
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• 제37권1호
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• pp.49-56
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• 2002

UV 조사시간과 오존유량을 변화시키면서 폴리프로필렌을 UV/오존 산화하였으며 이의 표면특성을 접촉각과 XPS를 이용하여 살펴보았다. 산화된 표면의 노화거동을 공기, 물, 에틸렌 글리콜 하에서 살펴보았으며, 또한 lap shear 실험을 통하여 접착력을 관찰하였다. 극성표면 에너지와 접착력은 UV/오존 처리시간과 오존유량이 증가함에 따라 증가함을 알 수 있었다. 물에서 노화실험을 한 경우 극성표면 에너지의 변화가 없었으나, 공기 하에서 실시한 경우 2-3일 이내에 급격히 감소하여 처리하지 않은 폴리프로필렌의 값에 근접하였다.

• 폴리머
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• 제37권4호
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• pp.494-499
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• 2013

이축압출기(twin screw extruder)를 이용하여 용융상태에서 furfuryl sulphide를 분지제로 개질 폴리프로필렌(modified polypropylene, m-PP)을 제조하고, 층상 실리케이트와 다중벽 탄소나노튜브(multi-walled carbon nanotube, MWCNT)와의 m-PP/나노필러 복합체를 제조하였다. m-PP의 화학구조와 열적 특성은 적외선분광기(FTIR), 시차주사열용량분석기(DSC)를 이용하여 관찰하였다. m-PP의 화학구조는 3100 $cm^{-1}$에서 나타나는 분지제의 =C-H 신축진동피크를 이용하여 확인하였고, 용융온도는 큰 변화를 보이지 않았지만 결정화온도는 $10-20^{\circ}C$ 가량 증가하였다. m-PP/나노필러 복합체의 유변학적 특성과 분산성 및 발포거동은 동적유변측정기, X-선 회절분석기(XRD), 주사/투과전자현미경(SEM/TEM)을 이용하여 관찰하였다. m-PP/나노필러 복합체의 낮은 주파수 영역에서의 복합점도와 용융탄성이 증가하였으며, 전단담화(shear thinning) 효과 또한 증가하였다. 순수 PP와 비교할 때 m-PP와 m-PP/나노필러 복합체의 발포 거동 개선효과가 우수한 것을 확인하였다.

• Korea-Australia Rheology Journal
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• 제13권2호
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• pp.61-65
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• 2001

Thermoplastic nanocomposites based on the copolymers of polypropylene (PP)-polystyrene (PS) and organically modified montmorillonite (org-MMT) were produced by using power ultrasonic wave in an intensive mixer. Owing to the unique action of the ultrasonic wave, free radicals of styrene monomers and macroradicals of PP were generated, by which copolymers of PP and PS were formed. Another important aspect of using ultrasonic wave during the mixing process was to enhance nano-scale dispersion of org-MMT by destructing the agglomerates of org-MMT in the polymer matrix. Optimum conditions for the in-situ copolymerization and melt intercalation were studied with various concentrations of styrene monomer, sonication time and different kinds of clay. It was found that a novel attempt carried out in this study yielded further improvement in the mechanical performance of the nanocomposites compared to those produced by the conventional melt mixing process.

• 전기학회논문지
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• 제60권10호
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• pp.1881-1887
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• 2011

In this work the recyclable new polyethylene(PE) and polypropylene(PP), which are thermoplastic, have been investigated as the eco-friendly insulating candidates to replace the cross-linked polyethylene (XLPE). The temperature dependence of conductivities of these materials has been measured and its effects on electric field and space charge distribution in polymeric insulated power cable under temperature gradient have been calculated. It is shown that the sensitivity of conductivity to temperature change has more critical influence to determine the electric field distribution in the power cable than the absolute value of conductivity does and it can be said that the temperature dependence is one of most important factors for the power cable design.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.291-291
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• 2006

Two different sources of clay, Na-Bentonite (Thai local clay) and Na-Montmorillonite were modified with Hexadodeccyltrimethyl ammonium bromide. The nanocomposites of polypropylene were successfully prepared via melt blending in a co-rotating twin screw extruder by using PP-g-MA as a compatibilizer at various contents of organoclays. The morphology of nanocomposites was investigated by using XRD and SEM. The results showed that the intercalated and exfoliated structures were obtained. The thermal behavior was also studied by using DSC and TGA. The degradation temperature of filled PP was greater than that of unfilled PP by 20%. And, the tensile strength and modulus were improved when a small amount of organoclays were added.