Preparation and glass transition temperatures of elastomeric PolyHIPE materials

Abstract

Highly porous elastomeric PolyHIPE materials have been prepared by polymerisation of the continuous phase of high internal phase emulsions (HIPEs) containing styrene, divinylbenzene and varying amounts of either 2-ethylhexyl acrylate or the corresponding methacrylate monomer. The glass transition temperatures of the resulting copolymers were investigated by differential scanning calorimetry (DSC). For each series,T_g was found to vary non-linearly with copolymer composition. By consideration of the comonomer unit sequencing along the polymer backbone, as deduced from reactivity ratios, the relationship between T_g and composition in each case has been qualitatively explained. Comparison between experimental results and values calculated using an entropic approach have been made. It is thought that the (meth)acrylate comonomers reduce the overall T_g by three mechanisms: by introducing large amounts of free volume, due to their bulky side groups; by providing a much higher degree of flexibility to the polymer chains; and by reducing the proportion of adjacent styrene units, which display particularly unfavourable steric interactions.

References

1. D. Barby and Z. Haq, Eur. Pat. 0,060,138 ( 1982)(to Unilever).
2. J. M. Williams and D. A. Wrobleski, Langmuir, 1988, 4, 656.
3. N. R. Cameron and D. C. Sherrington, Colloid Polym. Sci., 1996, 274, 592.
4. J. M. Williams, A. J. Gray and M. H. Wilkerson, Langmuir, 1990, 6, 437.
5. J. Kizling and B. Kronberg, Colloids Surf., 1990, 50, 131.
6. M. P. Aronson and M. F. Petko, J. Colloid Interface Sci., 1993, 159, 134.
7. P. Hainey, I. M. Huxham, B. Rowatt, D. C. Sherrington and L. Tetley, Macromolecules, 1991, 24, 117.
8. A. Guyot, Synthesis and Structure of Polymer Supports, in Syntheses and Separations using Functional Polymers, ed. D. C. Sherrington and P. Hodge, Wiley, New York, 1988, ch. 1.
9. P. W. Small and D. C. Sherrington, J. Chem. Soc., Chem. Commun., 1989, 1589.
10. H. F. M. Schoo, G. Challa, B. Rowatt and D. C. Sherrington, React. Polym., 1992, 16, 125.
11. E. Ruckenstein and L. Hong, Chem. Mater., 1992, 4, 122.
12. N. R. Cameron and D. C. Sherrington, Adv. Polym. Sci., 1996, 126, 163.
13. Polymer Handbook, ed. J. Brandrup and E. H. Immergut, 2nd edn., Wiley Interscience, USA, 1975.
14. B. B. Kine and R. W. Novak, Acrylic and Methacrylic Ester Polymers, in Encyclopedia of Polymer Science and Engineering Vol. 1, Wiley-Interscience, USA, 1985.
15. T. G. Fox, Bull. Am. Phys. Soc., 1956, 1, 123.
16. E. A. DiMarzio and J. H. Gibbs, J. Polym. Sci., 1959, 40, 121.
17. J. M. Barton, J. Polym. Sci., Polym. Symp., 1970, 30, 573.
18. N. W. Johnston, J. Macromol. Sci., Rev. Macromol. Chem., 1976, C14, 215 and references therein.
19. K. H. Illers, Kolloid-Z., 1963, 190, 16.
20. J. Schellenberg and J. Vogel, J. Polym. Sci. B, Polym. Phys., 1995, 32, 1969.
21. D. P. Gregory, Unilever Research, Port Sunlight, personal communication.
22. S. Loshaek, J. Polym. Sci., 1955, 15, 391.
23. L. E. Nielsen, J. Macromol. Sci., Rev. Macromol. Chem., 1969, C3, 69.
24. T. G. Fox and S. Loshaek, J. Polym. Sci., 1955, 15, 371.
25. J. Bicerano, R. L. Sammler, C. J. Carriere and J. T. Seitz, J. Polym. Sci. B, Polym. Phys., 1996, 34, 2247.