Dually reinforced all-polyamide laminate composites via microencapsulation strategy

Abstract

A new two-stage strategy is disclosed for the preparation of all-polyamide laminate composites based on polyamide 6 (PA6) matrices reinforced by high volume fractions of polyamide 66 (PA66) textile structures and three different types of nanoclays. In the first stage, PA6 microcapsules (MC) loaded with montmorillonite nanoclays (MMT) are synthesized by activated anionic ring-opening polymerization of e-caprolactam in solution in the presence of three different organically treated MMT brands. In the second stage, the MMT-loaded MC obtained with controlled molecular weight, composition and granulometry are compression molded in the presence of PA66 textile structures to produce the final dually reinforced laminate composites. Mechanical tests in tension, flexion, and impact for selected composites in this study showed up to 73% increase of the Young’s modulus, up to 142% increase of the stress at break, and more than a fivefold increase of the notched impact resistance. The mechanical behavior of the dually reinforced composites was discussed in conjunction with the morphology of the samples studied by optical and electron microscopy, and the matrix crystalline structure as revealed by DSC and microfocus synchrotron X-ray diffraction.