• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.303-304
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• 2013

The field application through the quality control of self adhesive rubberized asphalt waterproofing sheet was regulated by KS F 4934 of Korea Standard in 2003. However, the regulations that the different material properties of self-Adhesive waterproofing sheets are difficult to quality control on the standard. Therefore, this research was performed for of quality control all affiliations of self-adhesive waterproofing sheet through basic properties test and proposed quality standard revised bill in KS F 4934.

• Elastomers and Composites
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• 제54권1호
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• pp.35-39
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• 2019

Four different polymer compounds were prepared from four kinds of plasticizers, viz. di-2-ethylhexyl azelate (DOZ), di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl sebacate (DOS), and di-2-butyl sebacate (DBS), for making cable sheaths for ships. Ethylene-vinyl acetate and ethylene-propylene-diene-copolymer as matrix polymers and ethylene-vinyl acetate grafted maleic anhydride as a coupling agent were compounded with a flame retardant, crosslinking agent, filler, and other additives, besides the plasticizer to obtain the polymer compounds. The polymer containing DOZ showed the highest MH and ${\Delta}T$ in the rheology test, while that containing DBS was found to have the lowest tensile strength and highest elongation because of low ${\Delta}T$. The four polymers showed similar values (31.7-31.9) for flame resistance, while the polymer containing DOZ showed the highest value for cold resistance.

• Elastomers and Composites
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• 제49권1호
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• pp.43-52
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• 2014

브롬화 이소부틸 이소프렌 (BIIR) 고무의 점착성에 미치는 나노점토(Cloisite 20A)의 영향을 조사하였다. 고무내 나노점토의 분산성은 SEM, TEM, XRD으로 분석하였다. 나노점토 충전 및 미충전 고무의 열적안정성은 TGA로 분석하였으며, 충전고무에서 열적안정성을 보였다. 또한 나노점토를 첨가하면 보강효과에 의해 고무의 강도가 증가하였다. 나노점토 첨가로 계면간 분자확산 정도는 감소할 것으로 판단되었지만, 본 연구에서 관찰된 분자확산에 의해 형성된 계면의 두께는 분자사슬간 엄킴현상을 유발하는데 충분하여 계면점착력이 증가하는 것으로 나타났다. 계면점착력 증가현상은 일정한 이상 (8 phr)의 나노점토가 첨가되었을 때 나타났다. 나노점토 첨가에 따른 표면특성의 변화를 조사하기 위해 접촉각 측정을 하였는데 큰 변화는 관찰되지 않았다.

• Elastomers and Composites
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• 제34권2호
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• pp.156-176
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• 1999

Rubber chemicals such as accelerators, antidegradants, vulcanizing agents, processing agents and retarders are very important to the production and protection of tires and rubber goods. The use of accelerators and antidegradants are evaluated in various tire components. This paper will focus on how to vulcanize tires economically and maintain the physical properties of each tire component without severe degradation due to oxygen, heat and ozone. Also, new non-nitrosoamine accelerators and non-staining antiozonants will be discussed. Lastly, the future requirements of antidegradants and accelerators in the tire industry will be reviewed. Tires have been vulcanized with Sulfenamides as primary accelerators and either Guamdine's or Thiurams as secondary accelerators to achieve proper properties at service conditions. However, interior components such as the carcass can be vulcanized with Thiazoles as a primary accelerator to cure faster than the external components. Using the combination of Sulfenamide with secondary accelerators in a tire tread compound and the combination of a Thiazole and Guanidine in a carcass compound will be presented with performance data. Uniroyal Chemical and another Rubber Chemical Manufacturer have developed, "Tetrabenzyl Thiuram Disulfide," (TBzTD) as a non-Nitrosoamine accelerator, which could replace Nitrosoamine generating Thiurams. This new accelerator has been evaluated in a tread compound as a secondary accelerator. Also, Flexsys has developed N-t-butyl-2-benzothiazole Sulfenamide (TBSI) as a non-Nitrosoamine accelerator which could replace 2-(Morpholinothio) -benzothiazole (MBS), a scorch delayed Sulfendamide accelerator. TBSI has been evaluated in a Natural Rubber (NR) belt skim compound vs. MBS. An optimum low rolling resistant cure system has been developed in a NR tread with Dithiomorpholine (DTDM). Also, future requirements for developing accelerators will be discussed such as the replacement of DTDM and other stable crosslink systems. Antidegradants are divided into two different types for use in tire compounds. Internal tire compounds such as apex, carcass, liner, wire breaker, cushion, base tread and bead compounds are protected by antioxidants against degradation from oxygen and heat due to mechanical shear. The external components such as sidewall, chafer and cap tread com-pounds are protected from ozone by antiozonants and waxes. Various kinds of staining and non-staining antioxidants have been evaluated in a tire carcass compound. Also, various para-phenylene diamine antiozonants have been evaluated in a tire sidewall compound to achieve the improved lifetime of the tire. New non-staining antiozonants such as 2, 4, 6-tris-(N-1, 4-dimethylpentyl-p-phenylene diamine) 1, 3, 5 Trizine (D-37) and un-saturated Acetal (AFS) will be discussed in the tire sidewall to achieve better appearance. The future requirements of antidegradants will be presented to improve tire performance such as durability, better appearance and longer lasting tires.

• 한국건설순환자원학회논문집
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• 제5권3호
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• pp.267-274
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• 2017

본 연구는 상수도 급수과정에 사용되는 대구경 강관이 정수과정에서 사용되는 약품으로 인하여 부식이 발생하게 되고 이를 보수하기 위하여 친환경 소재인 EVA 시트 및 강관과의 부착을 용의하게 할 수 있는 부틸고무를 적용하여 자착식 방수방식 시트를 개발하였다. 이에 자착식 방수방식 시트에 대한 강판과의 부착강도를 확인하고, 강관에 발생될 수 있는 다양한 환경조건에서의 부착강도를 확인하였다. 또한 외부에서 침입하는 유입수의 수압에 의해 강관에 부착된 시트의 탈락여부를 확인하였으며, 마지막으로 강관이 부식된 환경과 유사하게 강판에 녹을 발생시켜 자착식 방수방식 시트와 부착강도를 확인함으로써 대구경강관 보수 시 시공 용의성 외에도 안정적인 부착강도를 확보하여 강관의 부식을 차단함과 동시에 안정적인 성능 유지 방안을 확인하고자 하였다. 그 결과 본 연구에 사용된 자착식 방수방식 시트는 강관에 대한 무처리, 장기 누름, 장기 침수 내화학(염산, 차아염소산, 수산화나트륨), 저온($-20^{\circ}C$) 및 습윤 건조 반복에서의 모든 부착성능은 KS F 4934의 성능기준인 1.5N/mm 이상을 상회하는 부착강도가 나타났으며, 배면 누수압에 따른 시트의 탈락현상을 확인하는 시험에서도 배면 누수압 $3.0N/mm^2$까지 시트의 탈락이 발생되지 않았다. 또한 녹이 발생된 강관에서의 부착성능을 확인하는 과정에서도 12시간동안 녹을 발생시킨 시험편에서 2.1N/mm, 168시간동안 녹을 발생시킨 시험편에서 2.0N/mm 의 성능이 나타남에 따라 녹 발생 강관에 대한 안정성이 확인되었다.

• Elastomers and Composites
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• 제43권4호
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• pp.230-240
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• 2008

분산중합법에 의해 무기물을 포함하는 고분자 미립자를 합성하기 위해 styrene과 n-butyl methacrylate가 알루미나와 함께 중합되었다. Styrene과 n-butylmethacrylate의 무게 비는 3:1이었고, 입자안정제는 poly(N-vinyl pyrrolidon), 중합 개시제로는 2,2'-azobis(isobutyronitrile)를 사용하여 개시제의 농도, 분산매의 종류, 분산매의 혼합 용해도 상수 (${\delta}_{mix}$), 커플링제의 종류와 농도에 따른 입자경을 조사하였다. 개시제의 농도가 증가함에 따라 입자경이 소폭 상승하였고 분산매의 극성이 증가할수록 입경이 증가하였고, 분산매로서, 이소프로판올과 이온교환수를 조성비에 따라 사용한 경우, $[{\delta}_{mix}]^{-4.01}\;{\propto}$ 평균 입자경과 $[{\delta]_{mix}]^{-0.83}\;{\propto}$ 입경 분포의 관계를 얻을 수 있었다. 커플링제의 종류와 농도변화에 따른 입자경 및 입자경 분포는 뚜렷한 차이가 없었다.

• Elastomers and Composites
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• 제45권2호
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• pp.122-128
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• 2010

소수성실리카를 안정제로 하는 현탁중합반응법을 이용하여 합성한 스티렌(St)/부틸메타크릴레이트(BMA) 공중합체 (co-PSB) 입자의 전단점도를 모세관 레오미터 (capillary rheometer)를 이용하여 $170^{\circ}C$에서 측정하였다. co-PSB 입자의 전단점도는 중량평균분자량이 74,800 g/mol 이하인 경우 낮은 전단속도에서는 뉴톤거동을 보였다. 중량평균분자량이 136,800 g/mol을 초과하면서 전단점도는 전단속도의 전 영역에 걸쳐 감소하였고 전단속도에 대한 기울기의 절대값은 분자량의 증가와 함께 증가하였다. St/BMA의 구성비가 7/3, 5/5 및 3/7의 co-PSB 입자는 유사한 분자량을 나타내었지만 BMA의 구성비가 증가하면서 유리전이온도와 전단점도는 감소하였다. St/BMA의 구성비가 1/9 인 co-PSB의 경우 유리전이온도는 더욱 감소하였으나 초기 전단점도는 크게 증가하였다. 카본블랙을 함유하는 co-PSB 복합체 입자의 전단점도는 카본블랙의 증가에 따라 증가하였으나, 카본블랙의 농도에 따른 전단점도의 변화는 분자량 및/혹은 구성비의 변화 효과에 비교하여 미약하였다.

• 전기학회논문지
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• 제63권7호
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• pp.1008-1012
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• 2014

Tunnel bracket is used in railway tunnel area in order to maintain insulation. Insulator performance evaluation test is proceeded refer to IEC 61109 but it is impossible to reflect all the field condition where insulator installed. Korea has clear four season in climatic condition and peninsula with lots of mountain in geomorphology condition. Tunnel bracket material which used in korea are butyl rubber, polymer and silicone. Most of them were installed without any internal climatic and geomorphology condition. According to the KORAIL operation data most of the insulator break down occurs in tunnel. So interval of inspection period is shorter then any other insulator and lots of maintenance cost incurs. Most major railway advanced country such as germany and japan maintain tunnel bracket with their own experience. For example visual inspection carried out with in one or two years and detailed inspection carried out between three to five years. This paper analyzed materials and shapes of tunnel bracket to in order to find optimized one in korea peninsula. Proposed bracket were tested under regulation and experience field data. Finally it was installed at the field and evaluated until now.

• Elastomers and Composites
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• 제57권3호
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• pp.100-106
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• 2022

Waterborne polyurethane-acrylate(WPUA) dispersions were prepared by surfactant-free emulsion polymerization in a two-step process. In the first step, polytetrahydrofuran, isophorone diisocyanate, dimethylol proponic acid, and 2-hydroxyethyl methacrylate were used to synthesize a vinyl-terminated polyurethane prepolymer. In the second step, styrene, methyl methacrylate, butyl acrylate, and different multi-functional crosslinkers were copolymerized. 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate were used as the crosslinkers, and their effect on the mechanical and thermal properties of WPUA was investigated. Overall, as the number of functional groups of the cross-linker increased, the gel fraction improved to 79.26%, the particle size increased from 75.9 nm to 148.7 nm, and the tensile strength was improved from 5.86 MPa to 12.40 MPa. In thermal properties, the glass transition temperature and decomposition temperature increased by 9.9℃ and 18℃, respectively. The chemical structures of the WPUA dispersions were characterized by Fourier-transform infrared spectroscopy. The synthesized WPUA has high potential for applications such as coatings, leather coatings, adhesives, and wood finishing.

• 한국산업보건학회지
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• 제19권4호
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• pp.321-327
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• 2009

1,3-butadiene is classified as suspected human carcinogen, group A2(American Conference of Governmental Industrial Hygienists, ACGIH). In Korea, 1,3-butadiene has been used as a raw material; monomer, homopolymer, polybutadiene latex, acrylonitrile-butadiene-styrene(ABS) and styrene-butadiene rubber(SBR), in the petrochemistry and precision chemistry industry. As petrochemistry industry in Korea has been developed, the potential exposure possibility of 1,3-butadiene to workers can be increased. Therefore the purpose of this study is to evaluate airborne 1,3-butadiene concentration and workers' exposure levels in the workplace using 1,3-butadiene. Air samples were collected with 4-tert-butyl catechol(TBC) charcoal tube(100 mg/50 mg) and were analyzed by gas chromatograph/flame ionization detector(GC/FID) according to the Choi's method(2002). Geometric mean (GM) and arithmetic mean (AM) of total 59 workers' exposure concentrations to airborne 1.3-butadiene were 0.042 ppm and 1.51 ppm, respectively. Although most samples were lower than 1ppm, 2 samples(21.5ppm and 33.1ppm as 8hr-TWA) were exceeded the Korean standard(2ppm) over 10 times at the repair process in synthetic rubber and resin manufacture industry. 14 samples(41%) of total 34 short-term air samples were exceeded the Korean standard(10ppm as STEL) of Ministry Labor. 1,3-butadiene concentration(GM) in the synthetic rubber and resin manufacture industry(7.87ppm) was significantly higher than that in the monomer manufacure industry (0.35ppm)(p<0.05). Also in the sampling and repair process, each GM(range) was 1.39ppm(N.D.-469.6ppm) and 7.85ppm(N.D.-410.2ppm). In conclusion, it depends on the industry and process, 1,3-butadiene can be exposed to workers as high concentration for short-term.