Biocomposites reinforced with natural fibers: 2000–2010

Current issues in research on structure–property relationships in polymer nanocomposites

It is demonstrated from stress-induced Raman bands shifts that stress can be transferred from a polymer matrix to a graphene monolayer (see image) in a model nanocomposite. It is shown further that the behavior can be modeled using continuum mechanics and that the interface between the graphene and the polymer breaks down at a shear stress of the order of 2 MPa.

Interfacial stress transfer in a graphene monolayer nanocomposite

Mechanical properties of the hexagonal boron nitride monolayer: Ab initio study

Exposure to extended periods of sub-Tg temperatures causes physical changes in the molecular structure of epoxy resins and epoxy-based materials to occur. These physical aging mechanisms include the reduction in free volume and changes to the molecular configuration. As a result, mechanical, thermodynamical, and physical properties are affected in ways that can compromise the reliability of epoxy-based engineering components and structures. In this review, the physical changes in the molecular structure of epoxies are described, and the influence of these changes on the bulk-level response is detailed. Specifically, the influence of physical aging on the quasistatic mechanical properties, viscoelasticity, fracture toughness, thermal expansion coefficient, volume relaxation, enthalpy relaxation, endothermic peak temperature, fictive temperature, and moisture/solvent absorption capability is reviewed. Also discussed are relationships between relaxation functions, crosslink density, composite reinforcement, and epoxy/copolymer blending and the physical aging response of epoxies. Finally, the concepts of thermal and mechanical rejuvenation are discussed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011

https://onlinelibrary.wiley.com/doi/pdf/10.1002/polb.22384

Physical aging of epoxy polymers and their composites

Reference EPFL-ARTICLE-184271doi:10.1016/j.compositesa.2012.08.001View record in Web of Science Record created on 2013-02-27, modified on 2017-05-10

Thomas Gmuer

Papers

Composites Part A: Applied Science and Manufacturing