Polymer matrix shear strength

Assuming that the applied stress is transferred to the MWNT via a nanotube-matrix interfacial shear mechanism at the molecular level, a modified force-balance which accounts for pullout angle and is based on the expression for the nanotube-polymer interfacial shear strength, x, may be as follows ... 

In using Eq. (6.10) to predict / , of a given composite system it is important that the said failure mechanisms all exist. If any one mechanism is apparently absent the corresponding toughness term must be excluded from the / t equation. It is also worth emphasizing that / , varies linearly with reciprocal of the frictional shear strength of the interface, i.e. l/tf, with the lower limit of (1 — Ff)/fm when if approaches infinity. This relationship has been shown to apply to many carbon fiber polymer matrix composites (CFRPs) (Harris et al., 1971 Beaumont and Phillips,... 

The interaction of two substrates, the bond strength of adhesives are frequently measured by the peel test [76]. The results can often be related to the reversible work of adhesion. Due to its physical nature such a measurement is impossible to carry out for particulate filled polymers. Even interfacial shear strength widely applied for the characterization of matrix/fiber adhesion cannot be used in particulate filled polymers. Interfacial adhesion of the components is usually deduced indirectly from the mechanical properties of composites with the help of models describing composition dependence. Such models must also take into account interfacial interactions. 

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