• 폴리머
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• 제24권6호
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• pp.837-844
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• 2000

본 연구에서는 반도체 봉지제로 사용되는 상용 EMC중 가속제의 함량이 다른 두 종류의 프리프레그에 대하여 그 경화거동을 등온 및 승온조건에서 시차 주사 역량계, 점도계 및 유전율 측정계를 이용하여 분석하였다. 경화반응 속도변수는 Kamal의 자동촉매 반응식을 이용하여 m+n을 2로 가정한 후 Ryan Dutta의 방법에 따라 계산에 의한 경화반응 속도의 예측 치와 실제 실험 데이터가 10$0^{\circ}C$를 제외한 나머지 온도에서는 잘 일치하는 경향을 나타내었다. 경화과정 중 겔화와 유리화와 같은 상 전이를 관찰하였으며 각각의 등온 경화온도에서 경화시간에 따른 유리전이 온도 ($T_{g}$ )를 측정하여 경화온도와 유리전이 온도가 같아지는 유리화점을 구할 수 있었고 절대온도와의 사이에 Arrhenius관계가 성립함을 확인하였다. 또한 평판형 전극을 이용한 DEA는 EMC의 경화 과정을 동정하는데 효과적으로 이용될 수 있음을 알 수 있었다. 같은 종류의 수지 시스템에서는 TTT diagram상에서 $_{gel}$$T_{g}$ 가속제의 농도에 상관없이 일정한 온도에서 나타남을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1570-1572
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• 1997

Characteristics of thermal degradation on cure conditions of DGEBA/MDA/GN system were investigated. Epoxy resin system was degradated in one stage. The activation energy of DGEBA/MDA/GN system had the lowest value in the cure time of 1.0 hr at $80^{\circ}C$ before at $150^{\circ}C$ for 1.0 hr and it increased with the pre-cure time at $80^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.548-551
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• 1999

The cure characteristics of metal particle filled DGEBA/MDA/SN/ zeolite epoxy resin composite system for EMI shielding were investigated by dynamic DSC run method and FT-lR spectroscopy. As the heating rate increased, the peak temperature on dynamic DSC curve increased because of the rapid cure reaction. From the straight line of the Kissinger plot, the curing reaction activation energy and pre-exponential factor could be obtained. As the post-curing time at 15$0^{\circ}C$ increased, the glass increased the glass transition temperature or the thermal stability increased. When the post curing time is too long, the system filled with metallic Al particle can be thermally oxidized by the catalytic reaction of metal filler and the thermal stability of the composite for the EMI shielding application may be decreased.

• Elastomers and Composites
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• 제53권3호
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• pp.168-174
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• 2018

Natural rubber (NR) and bromo-isobutylene-isoprene rubber (BIIR) were compounded with other formulation chemicals through polymer blending via a mechanical mixing method. After rubber vulcanization by hot-press compression molding, the cure characteristics, mechanical properties, and ozone resistance of the NR/BIIR blends were measured. As the BIIR content increased, the maximum torque of the blends decreased, while the optimum cure time and scorch time tended to increase. Furthermore, the hardness of the blends increased with increasing BIIR content, reaching the maximum value at 75 wt% BIIR, and decreased with a further increase in the BIIR loading. The tensile strength and elongation at break decreased with an increase in the BIIR content, reaching the minimum value at 75 wt% BIIR, and increased with a further increase in the BIIR content. In the ozone resistance test, cracks were not generated when the BIIR content was more than 75 wt%.

• 한국정밀공학회지
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• 제20권2호
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• pp.76-84
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• 2003

Stereolithography is the technique using a laser beam to cure a liquid resin, a photopolymer, with three dimensional computer-aided design (CAD) data. The build parameters of stereolithography such as beam size, scan velocity. hatch spacing, layer thickness and etc. are determined by the accuracy of prototype, the build time and the cured properties of the resin. In particular, beam size is important processing parameter fur the other parameters. Therefore, this study observed the cured property to beam size. For this purpose, according to hatch spacing and beam size, the cure width and depth were measured on single cured line. Also, the cure width and depth were measured at single cured layer As a result of experiments. cure depth which varied from 0.23mm to 0.34mm was directly proportioned to beam radius. on the other hand, cure width which varied from 0.42mm to 1.07mm was inversely proportioned to beam radius. Surface roughness varied from 1.12 to 2.23 m for the ratio of hatch spacing to beam radius.

• 대한소아치과학회지
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• 제23권4호
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• pp.906-914
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• 1996

Due to the various reason, sealing of pit & fissure might be imperfect. One of these reason can be the fracture of sealant material because of the low hardness value of sealing material. The purpose of this in vitro study was to evaluate the microhardness of two different curing type pit and fissure sealants: Dual-cure and Light-cure. The result from the present study can be summarized as follows: 1. All pit and fissure sealants that used in this study showed statistically significant difference in their microhardness of upper and lower surface. (P <0.05) 2. Except of lower surface of teethmate, microhardness of 40-second curing sealant was statistically higher than that of 20-second curing sealant. (P <0.05) 3. In comparison of sealants, microhardness of dual-cure sealant was statistically higher than that of light-cure sealant. Above results suggest that the use of dual-cure sealant and longer curing time are recommended.

• 대한소아치과학회지
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• 제26권3호
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• pp.554-563
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• 1999

심미적 수복재료인 복합 레진과 글래스 아이오노머 시멘트는 중합방식에 따라 화학중합형, 광중합형, 그리고 이 두 가지 중합방식을 겸비한 이중중합형으로 분류할 수 있다. 화학중합형과 광중합형에 대해서는 지금까지 다수의 보고가 있었으나, 충전용 복합 레진의 경우 이들과 이중중합형을 비교한 예는 아직 찾기 힘든 실정이었으므로, 이러한 관점에서의 연구가 필요할 것으로 사료되었다. 이 연구에서는 이중중합 수복재가 단일중합방식에 비해 어떠한 특성을 보이는지를 탐구하고자 하였다. 사용된 재료는 광중합형 복합 레진인 Veridonfil-Photo와 이중중합형인 Bis-core, 이중중합형의 글래스 아이오노머 시멘트인 Fuji II LC와 화학중합형인 Ketac-fil을 사용하였다. 가로 30mm, 세로 30mm, 높이 1mm와 3mm인 두 종류의 아크릴릭 몰드 중앙에 직경 7mm의 hole을 형성하여 여기에 4종의 수복재를 충전하였다. 충전 직후부터 시작하여 24시간 경과시까지 일정 시간의 간격으로 표면, 1mm, 3mm 깊이에서의 경도를 미세경도계(Shimadzu Micro Hardness Tester HMV-2000, Shimadzu Co. Japan)로 측정하였다. 측정치를 통계처리하여 얻은 결과는 다음과 같다. 1. 4 종의 수복재 모두에서, 중합직후에 비해 24시간 경과후의 미세경도가 증가되었다. 2. 중합 직후부터 24시간 경과시점까지의 미세경도를 측정한 결과, Ketac-fil을 제외한 나머지 수복재에서는 각 깊이간 경도의 차이가 있었다. 3. 각 수복제의 최종중합에 도달하는 시간을 조사한 결과, 이중중합형이 3min의 깊이에서 광중합형이나 화학중합형에 비해 중합이 더 오래 지속된 것으로 나타났다. 이상의 결과에서 조사광이 충분히 도달하지 못하여 중합이 현저히 떨어지는 수복재의 심부에도 이중중합방식을 사용할 경우에는 지속적인 중합반응이 일어나 중합도가 증가하는 것으로 나타났다.

• Elastomers and Composites
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• 제50권2호
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• pp.87-91
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• 2015

Cure characteristics of non-oil-extended solution SBR (S-SBR_NO) and oil-extended solution SBR (S-SBR_ EO) compounds reinforced with silica/carbon black were investigated. Minimum and maximum torques of S-SBR_ EO compounds were much smaller than those of S-SBR_NO ones. Delta torques of S-SBR_NO compounds were greater than those of S-SBR_EO ones, and that of S-SBR_NO compound increased with increase in the 1,2-unit content. Optimum cure time ($t_{90}$) of S-SBR compound decreased with increase in the 1,4-unit content, whereas it increased with increase in the 1,2-unit content. Cure rate index of S-SBR compound increased with increase in the 1,4-unit content, whereas it decreased with increase in the 1,2-unit content. Comparing cure characteristics of S-SBR_NO and S-SBR_EO compounds with the same 1,2-unit content, $t_{90}$s of S-SBR_EO compounds were longer than those of S-SBR_NO ones and cure rate indices of S-SBR_EO compounds were smaller than those of S-SBR_NO ones.

• Elastomers and Composites
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• 제31권1호
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• pp.33-42
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• 1996

NR, NBR, and CR rubber were prepared by mixing filler in various ratios. Their vulcanization characteristics and thermal properties were studied. Vulcanization characteristics were investigated using cure curve that had been obtained from oscillating disk rheometer study. The Arrhenius law is known to describe the relationship between cure time and temperature of most elastomers. Curing could be done by the addition of sulfur, peroxides, and proper acceleratores. The optimum cure time that affects desirable values of modulus and tensile strength of the vulcanizate is taken as t90 as measured by a rheometer. Rubbers were cured in the rheometer at temperatures ranging from $130^{\circ}C\;to\;180^{\circ}C$ in order to check the validity of the curing system used. A linear relationship between ln(ts2) and ln(t90) was found for all elastomers. The term sensitivity has been used to describe the relationship between a change of ts2 to the corresponding change of t90 due to an increment of temperature. This is related to the formula of the compound.

• 한국의류학회지
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• 제28권11호
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• pp.1507-1515
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• 2004

Washable wool was developed using environmental-friendly spray UV-cure technique. Photocrosslinkable polymer, dextran-methacrylate, was synthesized starting from natural biopolymer, dextran. The aqueous solution of dextran-methacrylate was applied to wool fabric with various concentrations to find out the optimum condition in minimizing felting shrinkage. The wool fabric subsequently cured by 365 nm UV, The effects of UV-cure time and photoinitiator concentration on felting behavior of wool were examined. As the concentration of dextran-methacrylate increased, the felting shrinkage decreased gradually. At concentration 0.5g/ml, the felting shrinkage of wool was negligible. Other properties such as air permeability, moisture content, wrinkle recovery, thickness and wettability were also evaluated. The surface coating of dextran polymer onto wool fiber was identified by SEM.