Abstract
Micromechanics models proposed by Nairn et al. and Hashin, which can treat imperfect bonded interfaces between fibers and matrix polymers, are evaluated to utilize the models for predicting accurate deformation of injection molded parts of short fiber reinforced thermoplastics. The treatment of the imperfect interfaces is essential to deal with a difference of the interface conditions which affect mechanical properties of the parts. In contrast, general micromechanics models, such as the Mori-Tanaka (MT) model, are not appropriate because a perfect bonded interface is assumed in the models. For the evaluation of the Nairn-Hashin (NH) models, we first compare the NH models with the MT model under the condition of the perfect interface. Elastic moduli calculated from the NH models almost agreed with that from the MT model. The NH models are then evaluated by using elastic moduli measured for randomly fiber-oriented films of short glass fiber reinforced polypropylene. By considering the imperfect interface parameters estimated from pull-out tests of a single glass fiber embedded in a polypropylene matrix, the NH models predicted the measured elastic moduli.
