Effect of modifier concentration on the fracture behaviour of rubber-modified PMMA
Izod fracture surfaces of blends of PMMA with various amounts of a rubber modifier were studied using scanning electron microscopy. Attention was focused on modes of crack initiation and propagation and on the role of the modifier in the fracture process. It was found that the impact strength of this class of materials increased monotonically with an increase in modifier concentration, at least up to 40 wt% modifier. Unmodified PMMA was studied to provide a basis for understanding the morphological features on the fracture surfaces of the rubber-modified blends. It was confirmed that PMMA fractures through the formation and rupture of crazes. This phenomenon was also found to occur in blends containing 10 wt% modifier. However, blends with 20 wt% modifier crazed only in the later stages of the fracture process, when the crack speed had exceeded some critical value. No evidence of crazing was found in blends with 30 and 40 wt% modifier loadings, although extensive plastic deformation was observed on the fracture surfaces.
KeywordsPolymer Electron Microscopy Scanning Electron Microscopy Rubber Plastic Deformation
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- 1.C. B. Bucknall, in “Toughened Plastics” Applied Science Publishers, London (1977) p. 182.Google Scholar
- 2.D. G. Gilbert and A. M. Donald, J. Mater. Sci. 21 (1986) 1819.Google Scholar
- 3.E. M. Hagerman, J. Appl. Polym. Sci. 17 (1973) 2203.Google Scholar
- 4.A. M. Donald and E. J. Kramer, J. Mater. Sci. 17 (1982) 1765.Google Scholar
- 5.C. B. Bucknall, I. K. Partridge and M. V. Ward, ibid. 19 (1984) 2064.Google Scholar
- 6.J. Milios, G. C. Papanicolaou and R. J. Young, ibid. 21 (1986) 4281.Google Scholar
- 7.D. Hull and T. W. Owen, J. Polym. Sci., Polym. Phys. Ed. 11 (1973) 2039.Google Scholar
- 8.R. P. Kusy and D. T. Turner, Polymer 18 (1977) 391.Google Scholar
- 9.M. J. Doyle, J. Mater. Sci. 17 (1982) 204.Google Scholar
- 10.Idem., ibid. 18 (1983) 687.Google Scholar
- 11.R. N. Haward and I. Brough, Polymer 10 (1969) 724.Google Scholar
- 12.K. Matsushige, Y. Sakurada and K. Takahashi, J. Mater. Sci. 19 (1984) 1548.Google Scholar