Epoxy-based composites find extensive application in electronic packaging due to their excellent processability and insulation properties. However, conventional epoxy-based polymers exhibit limitations in terms of thermal properties and insulation performance. In this study, we develop epoxy-based siloxane/silica composites that enhance the thermal, mechanical, and insulating properties of epoxy resins. This is achieved by employing a sol–gelsynthesized siloxane hybrid and spherical fused silica particles. Herein, we fabricate two types of epoxy-based siloxane/ silica composites with different siloxane molecular structures (branched and linear siloxane networks) and investigate the changes in their properties for different compositions (with or without silica particles) and siloxane structures. The presence of a branched siloxane structure results in hardness and low insulating properties, while a linear siloxane structure yields softness and highly insulating properties. Both types of epoxy-based siloxane/silica composites exhibit high thermal stability and low thermal expansion. These properties are considerably improved by incorporating silica particles. We expect that our developed epoxy-based composites to hold significant potential as advanced electronic packaging materials, offering high-performance and robustness.

이 논문에서는 교량받침 교체를 위한 에폭시 주입 공법을 제시하였다. 에폭시 주입 공법의 성능 평가를 위하여, 에 폭시 주입성 실험 및 통공앵커의 인발실험을 수행하였다. 에폭시 주입성 실험은 빈 공간을 갖고 있는 콘크리트 블록 내에 통공 앵커를 이용하여 에폭시를 주입하고, 콘크리트 블록을 절단한 후, 주입성능을 육안으로 관찰하였다. 또한, 인발실험은 2가지 형태의 통공앵커를 콘크리트 블록 내에 삽입하여 수행하였으며, 2가지 형태의 통공앵커에 대한 인발실험 결과를 비교하고, 케 미컬 앵커의 인발강도와도 비교하였다. 실험 결과 통공앵커는 교량받침 교체공사를 위한 에폭시 주입성과 인발성능이 우수한 것으로 나타났다.

본 연구에서는 기존 비내진설계 콘크리트 기둥의 내진성능 개선을 위해 기둥 면적의 80% 영역을 12K 능직 카본 섬 유(CFRP sheet)와 카본용 에폭시 수지를 사용하여 보강한 후 보강량에 따른 내진성능을 실험적으로 평가하였다. 실험을 위해 실 험실 단위에서의 준실대형 기둥을 제작하였으며, 유압 풀링잭을 이용하여 약 10%만큼의 일정한 축력을 가력한 다음 변위제어를 통해 최대 10%의 변위비만큼 각 변위 사이클당 2회씩 반복 재하하여 가력을 수행하였다. 실험 결과 2겹의 12K CFRP sheet 보 강의 경우 누적에너지소산이 6.6배 증가하였으며, 4겹의 경우 9.6배 증가하였다.

PURPOSES : On a thin epoxy overlay pavement, epoxy is placed on the existing bridge deck pavement, followed by the spraying of aggregates on it. The bond strength between the existing pavement and overlay pavement is an important factor representing the performance of the thin epoxy overlay pavement, in addition to the skid resistance and roughness. Therefore, the bond strength, skid resistance, and roughness of a thin epoxy overlay pavement constructed for field tests under various field conditions are examined in this study. METHODS : The usability of epoxy and aggregates on a thin epoxy overlay pavement is identified by testing their material properties in a laboratory. A construction test is performed using the pretreatment conditions of the existing pavement surface and the number of layers of overlay pavement as variables. The bond strength, skid resistance, and roughness are analyzed 3 d after constructing the test pavement, and immediately before and after applying repetitive traffic loadings at 6 months. RESULTS : When the existing pavement is in good condition, as in this study, the bond strength of the thin epoxy overlay pavement is affected more significantly by the existing pavement condition than the material properties of epoxy, in which destruction is indicated in the existing pavement. The skid resistance is affected primarily by the condition of the aggregates sprayed on the epoxy. The pavement on which the aggregates are well sprayed indicate a high skid resistance. The roughness is not affected by any variables, such as the pretreatment conditions, number of thin pavement layers, and repetitive traffic loadings. CONCLUSIONS : A long-term evaluation of the bond strength, skid resistance, and roughness will be conducted on a test pavement. In addition, another construction test will be performed to investigate the performance of a thin epoxy pavement overlaid on a bridge deck pavement under inferior conditions.

PURPOSES : Given that large-scale repair works of expressway bridge pavements have high maintenance cost and long traffic blocking time, the thin overlay method that maintains the existing pavement is attracting attention. In this study, because the bridge thin overlay has not been introduced in Korea yet, the basic physical properties of the epoxy thin overlay, which is mainly used for the bridge thin overlay, were investigated, and the skid resistance and bond performance were analyzed. METHODS : Basic physical property tests were performed on each of the epoxy binders, aggregates, and mixtures used in epoxy thin overlay. They were also compared and reviewed against foreign standards. The epoxy binders were tested for viscosity, gel time, and thermal compatibility. The aggregates were tested in terms of water absorption, specific gravity, and gradation. The compressive and flexural strengths of the mixtures were investigated. The epoxy thin overlay has the possibility of detachment of aggregates, so the skid resistance was tested according to the paving phase. In addition, to investigate the bond performance, which is the most important performance of the epoxy thin overlay, the bond strength test was performed by varying the moisture condition and treatment condition of the existing layer surface. RESULTS : The basic physical properties of the materials used in the epoxy thin overlays satisfied foreign standards except for the gradation of aggregates. The skid resistance did not satisfy the standard when the epoxy was exposed, whereas the skid resistance did satisfy the standard when the aggregates were exposed, even after the abrasion test. The bond strength of the epoxy thin overlay satisfied the standard in all cases. The bond strength was the highest when the relative humidity of the existing layer surface was 60%. CONCLUSIONS : The materials of epoxy thin overlay that could be obtained in Korea satisfied the basic physical property standards except for aggregate gradation. Given that the aggregate gradation could be adjusted, it can be concluded that the epoxy thin overlay could be introduced in Korea. In addition, it was confirmed that the skid resistance and bond strength of the epoxy thin overlay were high enough to be used in general road conditions. It was determined that the existing layer surface should maintain an optimal relative humidity of approximately 60% because the moisture condition affects the bond strength.

Since electric energy is used in industry, mass production and various conveniences are provided. To provide convenience for the construction and operation of such electric energy transmission and distribution facilities, it is increasing that the demand for special purpose vehicles, that is, telescopic aerial work platform vehicles. When working active electric work using the telescopic aerial work platform vehicles, due to active electric work is inevitable, it is essential to ensure insulation performance for the safety of the operator. In this paper, we study the design and development of mechanical properties for filament winding process of glassfiber/epoxy composite, it is required to boom of telescopic aerial work platform vehicles. The glass fiber/epoxy composite filament winding process and its mechanical properties were evaluated to replace the existing ATOS80 boom. By filament winding process it was obtained the mechanical properties required for the design analysis of the glass fiber/epoxy composite boom. Using this, the insulated boom for the 30m class aerial work vehicle was designed and was manufactured by applying the filament winding process. The fabricated composite boom was evaluated by the static strength test to meet the required strength. The maximum displacement was 84mm and the crack occurred at the maximum load of 8981N. It satisfied the maximum lifting load of 4900N and 210mm the maximum displacement required for the boom.

스테인레스 스틸에 대한 합성된 폴리우레탄-에폭시 수지의 기계적 특성은 SEM, FT-IR, 인장특성, 그리고 EIS에 의한 특정질량손실량, 입도분석 등에 의해 물성을 측정하였다. 친환경적인 중방식 도료에 관한 관심이 고조됨에 따라 스테인레스 등의 금속에 코팅하는 무용제 도료를 합성하였다. 폴리올, IPDI, 충진제, 실리콘 계면활성제, 촉매 등이 함유된 기존 중방식수지보다 폴리올, MDI, 충진제, 실리콘 계면활성제, 촉매가 함유되어 합성된 중방식수지의 도료가 온도변화에 따른 인장강도가 증가하였고, 전해성이 높은 용액 속에서 저헝력이 크게 측정되었으며, 내구력과 강도가 양호하였다. 견고한 중방 식수지의 기계적 특성은 가교와 부식환경의 차단력이 증가함에 따라 강도가 증가하였다. 결론적으로 중방식의 가교된 미세조직은 방청코팅이 어려운 스테인레스 스틸 같은 금속물질 코팅에도 좋은 실험결과를 보여주었다.

Due to rapid industrialization and urbanization, maintenance of high voltage transmission lines in narrow alleys, complex roads, or old factory areas is required. Since the existing aerial lift vehicle is made of steel, there is a risk of electric shock. Therefore, there is a need for the development of an insulated aerial lift vehicle that can prevent electric shock accidents during electrical work. In particular, the development of an insulated aerial lift vehicle is required in a recent work environment where live line work is inevitable. The development of composite insulation boom for the vertical swing type aerial lift vehicle is studied. The insulated boom was developed by applying glass fiber-epoxy composite and filament winding process. The developed insulated boom was verified by measuring dielectric breakdown strength, surface resistance and volume resistance according to ASTM D149 and ASTM D257.