Article
  • Isothermal Cure Kinetics of DGEBA Epoxy Resins Initiated by Thermal Latent Cationic Curing Agents Containing Hexafluorophosphate
  • Park SJ, Cho MS, Lee JR
  • Hexaflurophosphate가 함유된 열잠재성 양이온 경화제에 의한 DGEBA 에폭시 수지의 등온 경화 동력학
  • 박수진, 조민석, 이재락
Abstract
The effect of different cationic curing agents as thermal latent initiators containing hexafluorophosphate (PF6(-)), i.e., N-benzylpyrazinium hexafluorophosphate(BPHP) and benzyl 3-cyanopyrazinium hexafluorophosphate (BCHP)on the isothermal cure kinetics of the diglycidylether of bisphenol A (DGEBA) epoxy resin were investigated. Latent properties were in estigated by measuring the conversion as a function of cure temperature using dynamic DSC. It was found that the epoxy resin initiated with BCHP results in better latent properties in relatively low temperature ranges. In this work, the isothermal DSC thermograms indicated that the cure reaction rate strongly depended on the cure temperature, and the autocatalytic reaction accelerated by the hydroxyl group produced through the reaction between DGEBA and BPHP(or BCHP). Therefore, the cure reaction rates of DGEBA/BCHP system derived from Kamal-Sourour equation were faster than those of DGEBA/BPHP, and the cure activation energies characterized by Arrhenius reaction equation were relatively lower in the case of DGEBA/BCHP containing CN electron acceptor group. This seems to be a consequence of the enhancing of leaving activity of CN-added pyrazine from benzyl-pyrarazinium salts.

열 잠재 개시능력이 있는 PF6-음이온을 함유한 N-benzylpyrazinium hexafluorophos-phate(PBHP)와 benzyl 3-cyanopyrazinium hexafluorophosphate (BCHP) 각각을 diglycidylether of bisphenol A(DGEBA)계 에폭시 수지에 대한 경화제로 사용하여 등온 경화반응에 미치는 영향에 대하여 고찰하였다. 잠재능력은 동적 DSC를 이용하여 경화 온도의 함수로 전환율을 측정함으로서 조사하였으며, BCHP로 개시된 에폭시 수지가 낮은 온도에서 더 우수한 잠재능력이 있음을 보여주었다. 등온 열분석 결과, 경화 온도가 높아질수록 경화 반응이 빨라짐을 알 수 있었으며, 자촉매 반응은 DGEBA와 BPHP(또는 BCHP)의 반응 과정에서 생성되는 수산기가 촉매로 작용해 반응을 촉진시킴을 알 수 있었다. Kamal-Sourour식에 의한 결과에서는, BCHP에 개신 DGEBA의 경화 반응속도가 BPHP에 개시된 DGEBA의 경화 반응속도보다 빨랐으며, Arrhenius 반응식으로부터 구한 활성화 에너지는 전자 받게 추기가 함유된 DGEBA/BCHP 계가 상대적으로 낮은 값을 보였다. 이는 benzyl pyrazinium염으로부터 CN 함유된 pyrazine의 이탈능이 증가된 결과로 사료된다.

Keywords: curing kinetics; cationic initiator; epoxy cure system; activation energy

References
  • 1. May CAEpoxy Resins, Marcel Dekker, New York (1988)
  •  
  • 2. Crivello JV, Lee JL, Macromolecules, 14, 1141 (1981)
  •  
  • 3. Abu-Abdoun II, Ali A, Eur. Polym. J., 29, 1439 (1993)
  •  
  • 4. Pappas SP, Hill LH, J. Coat. Technol., 53, 43 (1981)
  •  
  • 5. Habermeier J, Reichert KH, Kamann K, J. Polym. Sci. C: Polym. Lett., 16, 2131 (1967)
  •  
  • 6. Crivello JV, Lam JHW, J. Polym. Sci. A: Polym. Chem., 18, 1021 (1980)
  •  
  • 7. Nakano S, Endo T, J. Polym. Sci. A: Polym. Chem., 34(3), 475 (1996)
  •  
  • 8. Gu J, Narang SC, Pearce EM, J. Appl. Polym. Sci., 30, 2997 (1985)
  •  
  • 9. Kim YC, Park SJ, Lee JR, Polym. J., 29, 759 (1997)
  •  
  • 10. Rosato SV, Dimattia DP, Rosato VDesigning with Plastics and Composites, Nostrand Reinhold, New York (1991)
  •  
  • 11. Uno H, Endo T, J. Polym. Sci. C: Polym. Lett., 26, 453 (1988)
  •  
  • 12. Mark HF, Bikales NM, Overberger CG, Menges GEncyclopedia of Polymer Science and Engineering, 2nd Ed., John Wiley, New York (1986)
  •  
  • 13. Lee JR, Kwon H, Park SJ, Lee SB, Polym.(Korea), 22(3), 435 (1998)
  •  
  • 14. Kamal MR, Sourour S, Ryan M, Soc. Plast. Eng. Technol. Paper, 19, 187 (1973)
  •  
  • 15. Sourour S, Kamal MR, Thermochim. Acta, 14, 41 (1976)
  •  
  • 16. Waters DN, John LP, Anal. Chem., 60, 53 (1988)
  •  
  • 17. Liu YL, Hsiue GH, Chiu YS, Jeng RJ, J. Appl. Polym. Sci., 61(10), 1789 (1996)
  •  
  • 18. Eloundou JP, Feve M, Harran D, Pascault JP, Angew. Makromol. Chem., 230, 13 (1995)
  •  
  • 19. Salla JM, Ramis X, Polym. Eng. Sci., 36(6), 835 (1996)
  •  
  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2023 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 1999; 23(3): 413-420

    Published online May 25, 1999