Differential scanning calorimetry

About: Differential scanning calorimetry is a research topic. Over the lifetime, 50315 publications have been published within this topic receiving 1152335 citations. The topic is also known as: DSC.

Hydration and Phase Behavior of Poly(N-vinylcaprolactam) and Poly(N-vinylpyrrolidone) in Water

Abstract: Phase transitions of poly(N-vinylcaprolactam) (PVCL) and poly(N-vinylpyrrolidone) (PVPy) in H2O and D2O were investigated by turbidimetry, differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy The phase diagram of PVCL solution is binodal with a lower critical solution temperature (LCST) of 325 °C and a critical concentration of about 5 wt % PVPy also undergoes a phase separation around 30 °C in aqueous 15 M KF solution The IR spectra of PVCL and PVPy in water critically change at the phase transition temperature (Tp) Above Tp the C−H stretching and the C−H bending bands shift to lower wavenumbers The amide I band of PVCL is divided into four components, and the intensities of the 1565, 1588, and 1625 cm-1 components increase and that of the 1610 cm-1 component decreases while the phase transition proceeds Addition of KCl and KF lower Tp of PVCL, whereas KI and KBr raise Tp Addition of methanol gradually raises Tp up to ca 40 vol % and steeply raises Tp at >

Melt mixing of polycarbonate/multi-wall carbon nanotube composites

Abstract: —Composites of polycarbonate (PC) with multi-wall carbon nanotubes (MWNT) of different concentrations are prepared by diluting a PC based masterbatch containing 15 wt% MWNT using melt mixing in a DACA-Micro Compounder (4 g scale). Electrical resistivity measurements indicate that the percolation of MWNT is reached between 1 and 1.5 wt%. In addition, melt rheology was applied as another sensitive method to detect the percolation of the nanotubes. Atomic Force Microscopy and visual observations of the composite dispersions in a PC-solvent were used to characterise the state of MWNT dispersion. Differential Scanning Calorimetry and Dynamic Mechanical Analysis were applied to detect changes in the glass transition temperature of PC as a result of processing and of MWNT interactions with the PC matrix including the state of dispersion. In addition, DMA confirmed the reinforcement effect of the nanotubes. The results show that the nanotube incorporation also influences the processing behaviour. Due to the enhan...

Thermally Induced Association and Dissociation of Methylcellulose in Aqueous Solutions

Abstract: Aqueous solutions of a methylcellulose, ranging from 030 to 249 wt %, were studied by means of micro differential scanning calorimetry (micro DSC) and rheology The effects of polymer concentration on the thermodynamic properties of these solutions were examined through a heating process and a following cooling process at a fixed rate of 1 °C/min Upon heating, an endothermic peak was observed at about 63 °C, which was independent of polymer concentration The total energy defined by the endothermic peak area was found to be a linear function of polymer concentration On the other hand, when samples were cooling from about 90 °C, a broad exothermic peak appeared at about 33 °C, and the peak height and its broadness increased with polymer concentration A shoulder was observed above the peak temperature of 33 °C, and the shoulder became more prominent with increasing polymer concentration to eventually appear as a second peak at about 40 °C The thermal analysis results clearly show that the association