AbstractsChemistry

This work correlates the chemistry of phenol-formaldehyde (PF) resins, its functionalities with their microstructural and mechanical properties in composite materials. The main focus is put on the development of the pores in dependence on the chemical composition of the resins and their influence on the structure of the material. Chemical characteristics of the synthesized resins are analyzed and physical/mechanical properties of the matrices based on PF resins are determined. Differences in the chemical properties are detected e.g. by FT-IR and NMR spectroscopy. They indicate the existence of similar molecular basic structure units, but different network conditions of the resins. DSC investigations point on different reaction mechanisms and temperatures; they reveal also their changed thermal behavior. The bulk matrix behavior differs from that of the composite based on the same resin due to the three dimensional stress and strain fields in the composites. The structure of the CFRP composites is strongly depended on the fiber/matrix interaction. The fiber matrix bonding (FMB) strength controls the load transfer via shear forces and therefore the segmentation of the fiber bundles.