Interaction between epoxy matrix and nanoparticle

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The core task of the TP1 in the first funding period was the quantitative imaging analysis of the mechanical properties of a nanoparticle (NP)-modified fiber-reinforced polymer (FRP). AFM-based local analysis of physico-chemical properties of the FRP showed the strong influence of the particle-matrix interphase on the mechanical properties as a function of surface modification. It has also shown that the results on the sub-micron scale agree very well with the results of macroscopic mechanical experiments such as flexural modulus, tensile modulus, elongation at break and tensile stress at break. The first period was focused on primary particles (14nm) and their interphase to the matrix. In the second period also measurements on agglomerates will be performed. These are studied in terms of the interphase between the nanoparticles and evaluated for their role under mechanical load. In addition, the work will be developed in two directions in order to obtain a comprehensive understanding of the property change of FRP along the process chain by embedding the NP.In order to investigate the influence of the particle surface in detail, chemical modification of the NP in a highly defined manner is carried out by Prof. Garnweitners group. These nanoparticles are embedded on a laboratory scale and examined by AFM and dielectric spectroscopy methods in the group Silbernagl/Sturm. Here, the interactive approach is retained to provide mechanical property maps of the embedded nanoparticles for use in numerical modelling (TP2, group of Prof. Rolfes). In addition, the analysis portfolio is complemented with broadband dielectric spectroscopy (BDS; group Silbernagl/Sturm). In contrast to AFM this method is not imaging-based but measures integrally over a material volume in mm³ area. However, this method provides molecular mobilities and thus even offers a higher sensitivity at the molecular level as the AFM: Frequency-dependent studies at various particle concentrations show the amount of particles and separately their matrix interactions or interphase. Temperature-dependent BDS allows conclusions whether molecular mobility is localized or cooperative. In addition to the analytical and synthetic core task TP1 cooperates with TP4 for introducing a new technique with which NP can be included at critical points in the composite material using nano-carrier fleece. These NP are embedded in electrospun thermoplastic fibers. The resulting fabric can be placed in the mold specifically, the fiber dissolves in the injected hot epoxy resin, leaving the nanoparticles in the matrix (Silbernagl/Sturm group).