Measurement of residual stress effects by means of single-particle composite tests

Harding, P. H.; Page, S. A.; Månson, J.-Å. E.; Berg, John C.

doi:10.1163/156856198x00182

Cited by 7 publications

(1 citation statement)

References 11 publications

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“…The mold was allowed to cool slowly and then annealed for approximately 10 min at 10 ± C above the T g before the temperature was reduced to ambient and the mold allowed to cool. The slow cooling and annealing were intended to minimize residual stresses in the composite due to differences in thermal expansion coef cients between the matrix polymer and ller [19]. Since the maximum cooling rates obtained with the press are lower than those observed in industrial injection molding conditions [20,21], it is suspected that additional stress relaxation takes place as the composite is cooled down below T g .…”

Section: Mechanical Testsmentioning

confidence: 99%

The prediction of adhesion between polymer matrices and silane-treated glass surfaces in filled composites

Miller¹,

Berg²

2002

Journal of Adhesion Science and Technology

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Extending the database and the analysis of work reported earlier, the practical adhesion between a glass ller, modi ed by various silane coupling agents, and different polymeric matrices is measured and compared with predictions based on a generalized thermodynamic criterion. The criterion used is the magnitude of the (negative) molar Gibbs free energy of mixing, .¡1G mix / 0:5 , for a pseudo-solution consisting of equal molar amounts of the repeat units of the polymer matrix and the organo-functional group of the silane coupling agent. It is computed using the group contribution method of UNIFAC, in which molar volumes, molar areas, and molar interaction energies are constructed from contributions of the functional groups which make up the molecules of the solution. Measurements leading to the values of the adhesion strength are carried out using the singleparticle composite method, in which a rectangular polymer specimen containing a single silane-treated glass bead is subjected to increasing uni-axial tensile stress until interfacial failure, as observed using a microscope, occurs at one of the poles of the sphere. Earlier work reported a good correlation between the local stress at the pole computed from such measurements and the value of .¡1G mix / 0:5 computed using UNIFAC for ten different organo-silane-modi ed spheres imbedded in a poly(vinyl butyral) matrix. The present work extends the database to two additional matrices, viz. poly(methyl methacrylate) and poly(ethyl methacrylate). In addition, elastic fracture-mechanics theory is used to deduce speci c adhesion energies in all cases. The relative values of the latter are all found to be in good correlation with the predictive thermodynamic criterion.

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Section: Mechanical Testsmentioning

confidence: 99%