• Title/Summary/Keyword: 화학합성

Search Result 4,105, Processing Time 0.027 seconds

Synthesis of Zeolite A from Coal Fly Ash (석탄회로부터 제올라이트 A의 합성)

  • Jee, Jeong-Dae;Choi, Ko-Yeol
    • Applied Chemistry for Engineering
    • /
    • v.22 no.2
    • /
    • pp.214-218
    • /
    • 2011
  • Zeolite A was synthesized from coal fly ash by the microwave heating as well as the conventional heating method. The effects of reaction time, the amount of sodium aluminate, and the reaction temperature on the crystallization of zeolite A were investigated. The optimum crystallization time was about 3 to 6 h in the temperature range of $80{\sim}100^{\circ}C$. The amount of sodium aluminate was found to be optimum when the molar ratio $SiO_2/Al_2O_3$ of starting solution was in the range of 0.44 to 1.05 at above $90^{\circ}C$, However, The more amount of sodium aluminate was required to get zeolite A at $80^{\circ}C$. Although the rate of crystallization was slightly faster in the microwave heating than that in the conventional heating, the reaction time need to obtain fully crystallized zeolite A was similar in both methods. Therefore, the influence of the microwave heating was not so large compared with the conventional heating in the synthesis of zeolite A from coal fly ash.

Synthesis and characterization of PPG-based urethane-modified epoxy resin for enhancing impact resistance of epoxy composite resin (에폭시 복합수지의 내충격성을 향상을 위한 PPG 기반 우레탄 변성 에폭시 합성 및 특성 분석)

  • Hwang, Chiwon;Jeon, Jaehee;Ahn, Dowon;Yu, Youngchang;Lee, Wonjoo
    • Journal of Adhesion and Interface
    • /
    • v.23 no.2
    • /
    • pp.44-52
    • /
    • 2022
  • Epoxy resin has the disadvantage of being easily destroyed by instantaneous impact due to its high crosslinking density despite its high glass transition temperature (Tg) and excellent properties. To compensate for this, in this study, polyol was synthesized by ring opening polymerization of propylene glycol (PPG) diamine, Jeffamine D 2000 and propylene carbonate, and urethane modified epoxy was synthesized using this. The properties of the synthesized urethane modified epoxy were confirmed by FT-IR, H-NMR. To confirm the degree of improvement in impact resistance as an adhesive, a urethane modified epoxy adhesive was prepared by mixing a digylcidyl ether bisphenol A (DGEBA) with curing agent and curing accelerator. Properties test of urethane modified epoxy were shear strength, tensile strength and impact strength. As a result, excellent results were obtained in all test when the ratio of DGEBA : urethane modified epoxy was 8:2.

Chemical Fixation of Carbon Dioxide with Methane (메탄에 의한 이산화탄소의 화학적 고정화)

  • 조영복;김상채;서성규;유의연
    • Proceedings of the Korea Air Pollution Research Association Conference
    • /
    • 2000.11a
    • /
    • pp.389-390
    • /
    • 2000
  • 최근 지구 온난화의 55% 이상을 차지하고 있는 이산화탄소를 유용한 화합물로 전환하고자 메탄을 환원제로 사용한 이산화탄소 개질반응으로부터 합성가스 생성에 관한 연구가 활발히 진행되고 있다. 메탄의 이산화탄소 개질반응은 수증기 개질반응보다 낮은 합성 가스비의 생성, 온실효과를 유발하는 이산화탄소의 저감, 반응의 높은 흡열도를 이용한 화학에너지 전송 시스템의 응용 면에서 그 의의가 있다. (중략)

  • PDF