Article
  • A Study on the Characteristics of the Adiabatically Expanded Polyolefin Structured Foams
  • Hwang JH, Kim WN, Jun JH, Kwak SJ, Hwang SS, Hong SM
  • 단열 발포 폴리올레핀계 구조체의 특성에 관한 연구
  • 황준호, 김우년, 전재호, 곽순종, 황승상, 홍순만
Abstract
This study investigates the isothermal crystallization behaviors of polypropylene-polyethylene-(1-butene) terpolymer and the adiabatically expanded polyolefin structured foams. For this purpose, butane gas was used as a physical blowing agent. Avrami equation has been used to interpret theoretically the experimental results obtained by either DSC or polarized optical microscope. It is believed that elongation induced crystallization occurring during the adiabatic expansion process has resulted in an increase in crystallization rate, eventually leading to a faster growth rate of spherulites and an increase in the nucleation density. An analysis of the foam by SEM images showed that the structure of foam is uniform (below diameter 30 μm, closed cell) In addition, the thermal conductivity and the compressive strength of the polyolefin structured foams was measured. The thermal conductivity of foamed resin with excellent insulation characteristics is reduced compared with unfoamed resin. the compressive strength is decreased with increase in the expansion ratio.

폴리올레핀계 공중합체 수지인 polypropylene-polyethylene-(1-butene) 미발포 수지에 부탄 가스를 물리적 발포제로 이용하여 단열 팽창시킨 발포체의 등온 결정화 거동을 DSC(differential scanning calorimeter)와 편광 현미경을 이용하여 고찰하였으며, 얻어진 결과는 Avrami 식을 이용하여 해석하였다. 발포체의 결정화 반감 시간이 미발포체의 결정화 반감 시간보다 짧고 핵 생성 속도 증가에 따른 nucleation density 증가 및 구정 성장 속도가 더 빠름이 발견되었는데, 이는 가공 공정 중의 분자량 감소보다는 단열 팽창 과정에서 진행되는 연신 배향 결정화에 의해 결정화 속도가 증가하였기 때문인 것으로 사료된다. 또한, 단열 구조 발포체는 직경 30 μm 이하의 균일한 closed cell 형태를 나타내고 있음을 SEM을 이용하여 관찰하였고, 발포체의 물성은 미발포체에 비해 단열성이 크기 때문에 열전도도가 감소하였고 압축강도는 발포비가 증가할수록 감소하는 것을 알 수 있었다.

Keywords: crystallization; adiabatic expansion; elongation induced crystallization; thermal conductivity; closed cell

References
  • 1. Pop-Iliev R, Liu FY, Liu GB, Park CB, Adv. Polym. Technol., 22(4), 280 (2003)
  •  
  • 2. Park CB, Cheung LK, Polym. Eng. Sci., 37(1), 1 (1997)
  •  
  • 3. Naguib HE, Park CB, Reichelt N, J. Appl. Polym. Sci., 91(4), 2661 (2004)
  •  
  • 4. Klemper D, Frisch KCHandbook of Polymeric Foams and Foam Technology, Hanser, New York (1991)
  •  
  • 5. Colton JS, Mater. Manuf. Process., 4, 253 (1989)
  •  
  • 6. Seo KH, Lim JC, Polym.(Korea), 25, 701 (2001)
  •  
  • 7. Dominhaus HPlastics for Engineers, Hanser, New York (1993)
  •  
  • 8. Hoffman JD, Lauritzen JI, J. Res. Natl. Bur. Std. (U.S.), 65A, 297 (1961)
  •  
  • 9. Choi JB, Chung MJ, Yoon JS, Ind. Eng. Chem. Res., 44(8), 2776 (2005)
  •  
  • 10. Wunderlich BMacromolecular Physics, Crystal Nucleation, Growth, Annealing, Academic Press, New York (1976)
  •  
  • 11. Sperling LHIntroduction to Physical Polymer Science, John Wiley & Sons Inc., New York (1986)
  •  
  • 12. Velisaris CN, Seferis JC, Polym. Eng. Sci., 26, 1574 (1986)
  •  
  • 13. Lopez LC, Wilkes GL, Polymer, 29, 106 (1988)
  •  
  • 14. Jung SHPh. D. Dissertation, Korea Advanced Institute of Science and Technology(KAIST), Seoul, Korea (1998)
  •  
  • 15. Kowalewski T, Galeski A, J. Appl. Polym. Sci., 32, 2919 (1986)
  •  
  • 16. Hong SM, Kim BC, Kim KU, Chung IJ, Polym. J., 24, 727 (1992)
  •  
  • 17. Laurizen JI, Hoffman JD, J. Res. Natl. Bur. Stand(A), 64, 73 (1960)
  •  
  • 18. Keith HD, Padden FJ, J. Appl. Phys., 35, 1270 (1964)
  •  
  • 19. Chew S, Griffiths JR, Stanchurski ZH, Polymer, 30, 874 (1989)
  •  
  • 20. Deslandes Y, Dat M, Sabir NF, Suprunchuk T, Polym. Compos., 10, 360 (1989)
  •  
  • 21. Kumar S, Anderson DP, Adams WW, Polymer, 27, 329 (1986)
  •  
  • 22. Rybnikar F, J. Appl. Polym. Sci., 27, 1479 (1982)
  •  
  • 23. Thomann R, Wang C, Kressler J, Mulhaupt R, Macromolecules, 29(26), 8425 (1996)
  •  
  • 24. Baldwin DF, Park CB, Suh NP, Polym. Eng. Sci., 36(11), 1437 (1996)
  •  
  • 25. Colton JS, Suh NP, Polym. Eng. Sci., 27, 485 (1987)
  •  
  • 26. Rodeheaver BA, Colton JS, Polym. Eng. Sci., 41, 485 (2001)
  •  
  • 27. Sumarno, Sato Y, Takishima S, Masuoka H, J. Appl. Polym. Sci., 77(11), 2383 (2000)
  •  
  • 28. Martini J, Waldman F, Suh NPIn Proceedings of the SPE ANTEC '82,28,674, (1982)
  •  
  • 29. Goel SK, Beckman EJ, Polym. Eng. Sci., 34(14), 1137 (1994)
  •  
  • 30. Arora KA, Lesser AJ, McCarthy TJ, Macromolecules, 31(14), 4614 (1998)
  •  
  • 31. Rodriguez-Perez MA, Alonso O, Souto J, de Saja JA, Polym. Test, 16, 287 (1997)
  •  
  • 32. Almanza OA, Rodriguez-Perez MA, De Saja JA, J. Polym. Sci. B: Polym. Phys., 38(7), 993 (2000)
  •  
  • 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

  • 2005; 29(6): 605-612

    Published online Nov 25, 2005

  • Received on Oct 19, 2005
  • Accepted on Nov 21, 2005