Fracture Toughness of Epoxy Resins Containing Blends of Monomers with Different Molecular Weights

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The effect of adding a high molecular weight epoxy monomer (epikote 1001) to a low molecular weight one (epikote 828) on fracture toughness properties was investigated according to the crosslinking degree and density heterogeneity. To characterize the crosslinking degree and density heterogeneity, the glass transition temperature, Tg, and fragility, m, were deduced from thermo-viscoelastic properties. The characterization of Tg and m revealed that blends can be divided into two groups: one group with (φ < 10 wt%) and another one with (φ > 10 wt%), where φ is the weight ratio of epikote 1001 to epikote 828. The first group had the same average crosslinking degree (the same Tg) but different density heterogeneities (m decreased). The other group had a lower crosslinking degree (Tg decreased) and even more density heterogeneity (m decreased). The fracture toughness results showed that KIC of blends of the first group was approximately constant because the increase in density heterogeneity was still too weak (ineffective m), whereas KIC of blends of the second group was higher due to the simultaneous decrease in average crosslinking degree and increase in density heterogeneity. Therefore, the lower crosslinking degree (lower Tg) is and the more heterogeneous the blend (lower m) is due to the addition of high molecular weight monomer, the higher KIC becomes.

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Periodical:

Key Engineering Materials (Volumes 345-346)

Edited by:

S.W. Nam, Y.W. Chang, S.B. Lee and N.J. Kim

Pages:

1511-1514

Citation:

A. Haris et al., "Fracture Toughness of Epoxy Resins Containing Blends of Monomers with Different Molecular Weights ", Key Engineering Materials, Vols. 345-346, pp. 1511-1514, 2007

Online since:

August 2007

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$38.00

[1] T. Adachi, W. Araki, T. Nakahara, A. Yamaji and M. Gamao: J. Appl. Polym. Sci. Vol. 86 (2002), p.2261.

[2] W. Araki, T. Adachi, A. Yamaji and M. Gamao: J. Appl. Polym. Sci. Vol. 86 (2002), p.2266.

[3] W. Araki, T. Adachi and A. Yamaji: JSME Int. J., Series A Vol. 46 (2003), p.163.

[4] W. Araki, T. Adachi and A. Yamaji: Recent Res. Dev. Appl. Polym. Sci. Vol. 3 (2006), p.205.

[5] J.P. Pascault, R.J.J. Williams: J. Polym. Sci. B Vol. 28 (1990), p.85.

[6] K. Kanaya, I. Tsukushi, K. Kaji: Prog. Theoret. Phys. Suppl. Vol. 126 (1997), p.137.

[7] C.A. Angell: J. Phys. Chem. Solid Vol. 49 (1988), p.863.

[8] J.P. Benthem and W.T. Koiter, in: Asymptotic approximations to crack problems. In: Mechanical Fracture Vol. 1 Methods of analysis and solutions of crack problems, Noordhoff International Publishing, Leyden, (1975).

DOI: https://doi.org/10.1007/978-94-017-2260-5_3

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[1] 5 30 20 KIC [MPa. m 1/2 ] Tg [K] 10∼0 φ, wt% Fig. 5 Relationship between fracture toughness and fragility. 76 80 84 88.

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[1] 5 3020 10 5 10. 2 0. 5 0 φ, wt% KIC [MPa. m1/2 ] m.

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