Abstract
A fracture mechanics approach has been used to investigate the effects of the addition of physical modifiers on the fracture energy, G c, of brittle cyanate-ester polymers. Tests were performed using adhesive joint specimens at −55, 21 and 150°C, with all the specimens exhibiting cohesive failure in the cyanate-ester adhesive layer. The fracture energies of systems modified using a range of inorganic and thermoplastic particles, fibres and woven-mats have been measured, and scanning electron microscopy has been used to determine the toughening micromechanisms involved. Firstly, it is shown that the addition of 10% by weight of particulate modifiers can increase the fracture energy of the cyanate-ester polymer by 100%, due to a combination of toughening micromechanisms such as crack deflection, pinning and matrix cavitation around the second-phase particles. These experimental data have been compared to predictions from an analytical model. Secondly, it is demonstrated that the use of long fibres or woven-mats can give an a major increase in the value of the fracture energy, G c, at initiation, and a further increase with increasing crack length, i.e. a significant ‘R-curve’ effect is observed. At relatively long crack lengths, the measured fracture energy may be six times greater than that of the unmodified polymer value, due to fibres debonding and bridging across the fracture surfaces. Finally, it is shown that several of the physically-modified polymers developed in the present work have fracture energies that are greater than a typical commercially-available cyanate-ester film adhesive.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
B. HUSSEY and J. WILSON, “Structural Adhesives: Directory and Databook” (Chapman & Hall, London, 1996).
A. J. KINLOCH, “Adhesion and Adhesives: Science and Technology” (Chapman Hall, London, 1987).
A. W. SNOW, in “Chemistry and Technology of Cyanate Ester Resins,” edited by I. Hamerton (Blackie Academic & Professional, Glasgow, 1994) p. 7.
R. B. GRAVER, in“International Encyclopaedia of Composites,” edited by S. M. Lee (VCH Publishers, Cambridge, 1990) Vol. 1, p. 549.
D. A. SHIMP, in “Chemistry and Technology of Cyanate Ester Resins,” edited by I. Hamerton (Blackie Academic & Professional, Glasgow, 1994) p. 282.
I. HAMERTON, in “Chemistry and Technology of Cyanate Ester Resins,” edited by I. Hamerton (Blackie Academic & Professional, Glasgow, 1994) p. 1.
M. BAUER and J. BAUER, in “Chemistry and Technology of Cyanate Ester Resins,” edited by I. Hamerton (Blackie Academic & Professional, Glasgow, 1994) p. 58.
A. J. KINLOCH and A. C. TAYLOR, to be published.
British Standards Institute, BS-EN-573-1 (BSI, London, 1994).
C. UHLIG, Personal Communication, Fraunhofer Instit¨ut Zuverl¨assigheit und Microintegration, 1997.
UK Defence Standard 03-2/2 (1983).
“Adhesion, Adhesives and Composites Website, http://www.me.ic. ac.uk/materials/AACgroup/index.html” (Imperial College of Science, Technology and Medicine, 2001).
B. R. K. BLACKMAN and A. J. KINLOCH, in “Fracture Mechanics Testing Methods for Polymers, Adhesives and Composites,” edited by A. Pavan, D. R. Moore and J. G. Williams (Elsevier Science, Amsterdam, 2001) p. 225.
B. R. K. BLACKMAN, A. J. KINLOCH, A. C. TAYLOR and Y. WANG, J. Mater. Sci 35 (2000) 1867.
B. R. K. BLACKMAN, J. P. DEAR, A. J. KINLOCH, H. MACGILLIVRAY, Y. WANG, J. G. WILLIAMS and P. YAYLA, ibid. 30 (1995) 5885.
S. MOSTOVOY and E. J. RIPLING, J. Appl. Polymer Sci. 10 (1966) 1351.
D. A. SHIMP and S. J. ISING, in Proceedings of the 35th International SAMPE Symposium and Exhibition, Anaheim, CA, USA (SAMPE, Covina, CA, USA, 1990).
E. H. ANDREWS, “Fracture in Polymers” (Oliver & Boyd, Edinburgh, 1968).
R. E. GRIM, “Applied Clay Mineralogy” (McGraw-Hill, New York, 1962).
Microfine-Minerals, “Datasheet.”
P. BEGUELIN and H. H. KAUSCH, J. Mater. Sci. 29 (1994) 91.
B. R. K. BLACKMAN, A. J. KINLOCH and J. F. WATTS, Composites 25 (1994) 332.
K. T. FABER and A. G. EVANS, Acta Metal. 31 (1983) 565.
Idem. ibid. 31 (1983) 577.
A. J. KINLOCH, D. L. MAXWELL and R. J. YOUNG, J. Mater. Sci. Lett. 4 (1985) 1276.
Idem., J. Mater. Sci. 20 (1985) 4169.
Goodfellow Ltd., “Catalogue” (1998).
A. J. KINLOCH, G. K. A. and J. F. WATTS, Phil. Trans. R. Soc. Lond. A338 (1992) 83.
S. AZAM and J. P. SARGENT, J. Adhesion 71 (1999) 1.
Z. CAO, F. MECHIN and J. PASCAULT, Polymer Int. 34 (1994) 41.
I. HAMERTON, in “Chemistry and Technology of Cyanate Ester Resins,” edited by I. Hamerton (Blackie Academic & Professional, Glasgow, 1994) p. 329.
Potters-Ballotini, “Sphericel Datasheet.” Received 1 June and accepted 23 July 2001 460
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kinloch, A.J., Taylor, A.C. The toughening of cyanate-ester polymers Part I Physical modification using particles, fibres and woven-mats . Journal of Materials Science 37, 433–460 (2002). https://doi.org/10.1023/A:1013735103120
Issue Date:
DOI: https://doi.org/10.1023/A:1013735103120