Thermal characterisation of metal stearate lubricant mixtures for polymer compounding applications

Metal stearate blends are potential lubricants and filler dispersants in polymer compounding. Therefore, the thermal phase behaviour of binary blends of calcium stearate and magnesium stearate with zinc stearate was investigated. Cooling curve studies indicated lower melting temperatures in both systems. X-ray diffraction studies revealed that this was due to the formation of solid solutions of variable composition rather than to eutectic formation. Rheology measurements showed that true fluidification only happened well above the apparent melting points established from cooling curves. Calcium carbonate filled polyethylene containing metal stearate mixtures showed lower melt viscosities than were achievable using only calcium- or magnesium stearate as the lubricant. These results suggest that metal stearate blends, in combination with a judiciously selected wax component, may offer advantages in lowering compound melt viscosity and facilitating better particle dispersion.Sasol South Africa Limitedhttp://www.elsevier.com/locate/tca2023-02-25hj2022Chemical Engineerin

A novel cost-effective choline chloride/ionic liquid solvent for all-cellulose composite production

The potential of a blended cellulose solvent, consisting of a 1:1 mass ratio of choline chloride with the ionic liquid 1-ethyl-3-methylimadazolium acetate, was evaluated by using a film-casting technique. When comparing films produced with the neat ionic liquid to casting products from the mixed solvent, mechanical properties could largely be retained, while transparency was somewhat impaired. This is attributed to a fibrous microstructure and a higher degree of crystallinity caused by incomplete dissolution of the initial cellulose fibres. The presence of these residual fibres significantly reduced shrinkage during the film formation process. Functional group analyses, together with information on their crystallographic structure, proved that these film-like products should be classified as all-cellulose composites (ACCs). Statistical analyses of tensile properties justify further research on the mixed solvent system for cellulose processing.PAMSA and the Department of Science and Innovation.https://link.springer.com/journal/105702023-10-31hj2023Chemical Engineerin