Structurally graded polymeric materials and filled polymers, an integrated approach, Danish Research Councils, 1998 - 2003

The objective of the research is to study the effects of processing conditions and crystalline morphology of semicrystalline polymers and nanocomposites with polymeric matrices on their mechanical properties. Status for 2003 1. Experimental analysis and mathematical modelling of the nonlinear viscoelastic and viscoplastic behaviour of semicrystalline polymers. Work has been made on nonlinear mechanical behaviour of polymers and their time-dependent response (including the viscoelastic and viscoplastic phenomena). Polyethylene has been studied as well as Polypropylene under various deformation and load situations. 2. Experimental and theoretical study of the time-dependent behaviour of polymeric melts reinforced with nanofillers. A polymer-clay nanocomposite system has been studied to model the mechanical behaviour together with the diffusion properties of water into the system with various loads of fillers. 3. Experimental and theoretical study of rheological behaviour of polymeric melt with and without nanofillers. Current works in progress are on the development of a fair mixing route to ensure exfoliation. Work is concentrated on a modified montmorillonite clay-polypropylene nanocomposite. The use of a modified PP with additional polar groups to enhance exfoliation is necessary, and a maleated PP will be applied. Measurements are in progress on the influence on G? and G?? and the degradation behaviour of the system. 4. Rheological study of a Carbon nanotubes filled system in corporation with project 3A. The aim is to continue work on: 1. The mixing and preparation of an isotactic Polypropylene system containing maleated PP and a nano-clay (MMT). New dies are designed and will be tested for the optimal processing route. 2. The significant influence on the exfoliation and aggregation of clay platelets on the rheological behaviour makes oscillatory rheometry an excellent tool for structural dynamical investigations. The dynamic mechanical behaviour of the system will be studied, with a special focus on the time-property evolution. 3. The thermal properties and the kinetics of degradation will be studied by combining rheometry results with DSC/TGA and FTIR. This is especially relevant for drawing correct conclusions on the time-property evolution in the composites. Financing: Danish Research Councils and participating universities. Participants in Task B: Jesper deClaville Christiansen, Aleksey Drozdov and Yuan. Contact for the programme: Programme leader Ryzard Pyrz, Department of Mechanical Engineering, AAU. For Task B: Rheology and processing of graded polymers, Jesper deClaville Christiansen, Department of Production. (Jesper deClaville Christiansen, Department of Production, AAU)