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The Effect of Masked Isocyanates on the Mechanical Properties of My720/dds Epoxy Resin

Published online by Cambridge University Press:  22 February 2011

N. Rungsimuntakul ,
S.V. Lonikar ,
R. E. Fornes  and
R.D. Gilbert
N. Rungsimuntakul
Affiliation:
North Carolina State University, Fiber and Polymer Science Program, P. O. Box 8202, Raleigh, NC 27695-8202
S.V. Lonikar
Affiliation:
North Carolina State University, Fiber and Polymer Science Program, P. O. Box 8202, Raleigh, NC 27695-8202
R. E. Fornes
Affiliation:
Physics Department, P. O. Box 8202, Raleigh, NC 27695-8202
R.D. Gilbert
Affiliation:
North Carolina State University, Fiber and Polymer Science Program, P. O. Box 8202, Raleigh, NC 27695-8202
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Abstract

The mechanical properties of epoxy resins and epoxy resin/graphite fiber composites are adversely affected by moisture absorption. Incorporation of masked isocyanates that unmask to release isocyanates in situ at the cure temperatures (150-177ºC) reduce the equilibrium absorption up to ∼70%. Dynamic mechanical analyses and stress-strain properties of epoxy resins containing masked isocyanates were examined to determine their effect on mechanical properties. The ultimate Tg of the epoxy is reduced by incorporation of masked isocyanate, but the actual Tg is comparable to the “as cured” Tg of the epoxy. The dynamic moduli up to the Tg are relatively unaffected. Ina number of cases, the initial modulus, elongation at break and peak stress are equal or better than the unmodified resins.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 171: Symposium O – Polymer Based Molecular Composites , 1989 , 371
Copyright
Copyright © Materials Research Society 1990

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References

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