가교된 단분산 폴리스티렌 비드를 유화 중합과 분산 중합으로 합성하였다. 가교된 폴리스티렌 비드를 자일렌과 iron pentacarbonyl로 팽윤시킨 후 옥틸 에테르와 함께 환류하여 iron pentacarbonyl을 산화철로 변환시켰다. 산화철의 화학 안정성을 향상시키기 위해 산화철을 포함하는 폴리스티렌 비드를 실리카로 코팅하였다. 소결로 폴리스티렌 비드를 제거하여 산화철을 포함하는 중공 실리카 비드를 얻었다. 전체 합성 과정에서 모든 비드의 크기와 형태는 균일하게 유지되었고, 산화철을 포함하는 중공 실리카 입자는 강한 자성을 보였다.

프탈산염화물 또는 테레프탈산염화물과 4-니트로페놀로 부터 ortho 및 para catenation을 갖는 방향족 디아 민을 합성하였다. 이 방향족 디아민을 4,4‘-hexafluoroisopropylidenediphthalic anhydride (6FDA)와 반응시켜 폴리이미 드산을 합성하고, 이를 화학적으로 이미드화하여 폴리이미드를 얻었다. 얻어진 폴리이미드는 N-methyl-2-pyrrolidone (NMP)에 용해되었으며, 유연하고 질긴 필름으로 캐스팅 되었다. 폴리이미드의 5% 중량 감소는 440 ℃와 525 ℃에서 관찰되어 높은 열 안정성을 가짐을 확인할 수 있었다.

The vibration damping of various multilayer damping sheet with different constraining layer and viscoelastic layer were investigated by Rheovibron and vibration test. Damping increased as dynamic loss tangent increased. Constrained type damping sheet showed better damping than extensional type damping sheet. Aluminum foil attached asphalt impregnated paper pad showed best damping.

Recently carbon fiber reinforced plastic(CFRP) has been used structural materials in corrosive environment such as for water, chemical tank and chemical pipes. However, mechanical properties of such materials may change when CFRP are exposed to corrosive environment for long periods of time. Therefore, it is important to understand the effect of moisture absorption on mechanical properties of the CFRP. In this study, degradation behavior of immersed carbon fiber/epoxy resin composite material was investigated using acoustic emission(AE) technique. Fracture toughness test are performed on the compact tension(CT) test specimens that are pilled by two types of laminates [0˚2/90˚2]3s and [0˚2/90˚2]6sDuring the fracture toughness test, AE test was carried out to monitor the damage of CFRP by moisture absorption. In spite of the change of moisture absorption rate, the fracture toughness of CFRP was not change. As immersion time increased, AE event count numbers decreased in low amplitude range of AE for amplitude distribution histogram. The event in low amplitude range was known to be generated by debonding of matrix-fiber interface. Therefore, decrease of AE event count numbers in low amplitude range represents that debonding of matrix-fiber interface which was probably generated by moisture absorption.