Publications by authors named "Thijs Pijpers"

An experimental setup, making use of a Flash DSC 1 prototype, is presented in which materials can be studied simultaneously by fast scanning calorimetry (FSC) and synchrotron wide angle X-ray diffraction (WAXD). Accumulation of multiple, identical measurements results in high quality, millisecond WAXD patterns. Patterns at every degree during the crystallization and melting of high density polyethylene at FSC typical scanning rates from 20 up to 200 °C s(-1) are discussed in terms of the temperature and scanning rate dependent material crystallinities and crystal densities.

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A novel, powerful analytical technique, preparative temperature rising elution fractionation (prep TREF)/high-temperature (HT)-HPLC/Fourier transform infrared spectroscopy (FTIR)/high-performance differential scanning calorimetry (HPer DSC)), has been introduced to study the correlation between the polymer chain microstructure and the thermal behaviour of various components in a complex impact polypropylene copolymer (IPC). For the comprehensive analysis of this complex material, in a first step, prep TREF is used to produce less complex but still heterogeneous fractions. These chemically heterogeneous fractions are completely separated by using a highly selective chromatographic separation method--high-temperature solvent gradient HPLC.

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In order to fully exploit the graft copolymer poly(ethyleneglycol-g-vinylalcohol) (EG/VA) in the formulation of solid dispersions, a characterization of its phase behavior before, during and after spray-drying and hot-melt extrusion is performed. Solid state characterization was performed using MDSC and XRPD. The effect of heating/cooling rate on the degree of crystallinity was studied using HPer DSC and ultra-fast chip calorimetry.

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