Vincent Janssens

Publications (2)3.63 Total impact

• Article: RheoDSC: design and validation of a new hybrid measurement technique

  Vincent Janssens, Christophe Block, Guy Van Assche, Bruno Van Mele, Peter Van Puyvelde
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  ABSTRACT: A newly developed hyphenated technique is presented that combines an existing rheometer and differential scanning calorimeter (DSC) into a single experimental setup. Through the development of a fixation accessory inside the cell of the calorimeter and the introduction of an add-on unit for the rheometer, the simultaneous calorimetric and rheological measurement inside the well-controlled thermal environment of a Tzero™ DSC cell opens new experimental possibilities. The evolution of thermal and flow properties of a material can be simultaneously monitored during steady or oscillatory shear flow and regular or modulated temperature DSC measurements. The technique offers interesting opportunities for the investigation of flow-induced transitions, such as crystallization or phase separation, and provides a possibility for high-throughput screening of materials. The signal quality of the novel technique in comparison to the stand-alone techniques is demonstrated by the evaluation of the calibration factors and by measurements on standard materials. Finally, combined rheological and calorimetric melting and crystallization experiments on polycaprolacton are performed.
  Journal of Thermal Analysis and Calorimetry 04/2012; 98(3):675-681. · 1.60 Impact Factor
• Source

  Available from: Gerrit W M Peters

  Article: Suspension-like hardening behavior of HDPE and time-hardening superposition

  Peter C. Roozemond, Vincent Janssens, Peter Van Puyvelde, Gerrit W. M. Peters
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  ABSTRACT: The rheology of solidifying high-density polyethylene (HDPE) is investigated. Experiments on an HDPE were performed with a novel RheoDSC device. Results agree quantitatively with simulations for a suspension of elastic spheres in a viscoelastic matrix except for very low values of space filling (<5%), indicating that the rheological behavior of the crystallizing melt in the frequency range investigated is purely suspension like. The hardening behavior of the material is characterized in two different ways; a normalized rheological function and a time-hardening superposition (THS) master curve of rheological properties. An improvement is proposed to the procedure for performing THS that was previously used in the literature. Based on this procedure, a novel method for predicting the rheological properties of crystallizing melts is presented. KeywordsPolymer crystallization–Polyethylene–Rheology–Suspension models
  Rheologica Acta 04/2012; 51(2):97-109. · 2.03 Impact Factor