Lars Frormann

Thermal and Electrical Conductivities of Carbon Fibers and Carbon Nanotubes Incorporated Polyurethanes Composites

Single filler polyurethane composites with carbon fibers (CFs) and multi-walled carbon nanotubes (MWNTs) were prepared by melt mixing methods and its thermal as well as electrical resistivity characteristics were investigated. The influences of fillers and mixing methods on thermal and electrical conductivity of CF/- and MWNT/polyurethane composites were investigated and the result shows that the addition of carbon fillers improved the thermal conductivity of the polyurethane composites. Higher filler concentration results in better thermal conductivity because better formation of thermally conductive networks along polymer matrix to ensure the thermal was conducted through the matrix and the network along the polymer composites. The presence of carbon additives improves the electrical resistivity of the materials as well. The present study revealed the potential of carbon as agent for better thermal and electrical conductivities and their properties depend strongly on the dispersion and distribution of the fillers in the polymer matrix.

The Effect of Tri(n-butyl) Tin(IV) –2– [3–Benzoyl phenyl] Propionate on the Degradation and Stabilisation of PVC in Inert and Oxidative Atmospheres

Tri(n-butyl) tin(IV)–2–[3–benzoyl phenyl] propionate has been used to enhance the shelf life of rigid poly (vinyl chloride) (PVC). Studies of the thermal degradation of PVC have been a prime focus for a long time. Different substances have been tried to control and stabilise the process of thermal degradation. In the present work the aforementioned stabiliser has been used for this purpose. The samples of PVC containing different amounts of the stabiliser were prepared and treated at 190 ± 3 °C. The effect of the stabiliser on the degradation in nitrogen and air environments was studied through conductometric and spectroscopic measurements. The stabiliser was effective in slowing down the process of degradation. It also increased the initial induction period, i.e. the time during which no sign of degradation were observed. About 3% of stabiliser reduced the rate of the degradation of PVC by half, and almost doubled the induction period. It was more efficient in nitrogen than in air. These findings indicate that tri(n-butyl) tin(IV)–2–[3–benzoyl phenyl] propionate is a good inhibitor as well as an effective retarder.

Functional Materials for Energy Storage: Fabrication of Shape Stabilized Polymeric Phase Change Composites and the Determination of Their Thermophysical Properties for Use in Energy Conservation Applications

Several polymeric thermal energy storage composites of high density polyethylene and polypropylene with two commercial paraffin waxes (PCM) P27 and P31 were prepared. The compounds were further reinforced with carbon fibers and carbon nanotubes to improve their thermal conductivity and heat transfer efficiency. The impact penetration behavior, service temperature and solvent resistance of the composites were improved by the addition of SEBS. DSC, optical microscopy, SEM, impact penetration and time–temperature history studies of the materials were done to determine the structure and thermal properties of these composites. The paraffins provide energy storage effect by solid–liquid phase change. The polymers encapsulate the paraffins so that the fluid motion of the PCMs is reduced during an application. The composites prepared were used for the construction of a small prototype swimming pool (laboratory scale). The time–temperature history of the composites, water in the container with and without energy storage materials and the environment was recorded. It was found that the composites significantly prolonged the cooling down time for water in the PCM pool. The difference between the cooling down temperature of water in a container with and without PCM composite was almost 4 hours. Moreover a computer program in C++ was written to solve the heat flow equations for the calculation of theoretical temperature–time curves.Copyright