Extension of a Method for the Design of Divided Wall Columns

For most separations, a fully thermally coupled distillation column or divided wall columns are thermodynamically more efficient than conventional columns. This paper develops a method for the design of divided wall columns consisting of multi‐component mixtures (more than three components) with constant relative volatilities and a relatively sharp separation between the key components.     

Morphology and thermal properties of poly(ethylene terephthalate)‐modified kaolin nanocomposites

Kaolin particles were dispersed in a PET (poly(ethylene terephthalate)) matrix using a displacement procedure in which kaolin was initially treated with potassium acetate and, subsequently, melt‐blended with PEO and PET. The disappearance of characteristic peaks in XRD patterns of chemically treated particles revealed that the crystalline form and layered structure of kaolin particles were mainly destroyed. Scanning electron microscopy and transmission electron microscopy showed that the thickness of dispersed particles were generally in the range of 10–100 nm. It was also observed that the dispersion level of the chemically treated kaolin was much better than that of “as received” kaolin particles. Rheological studies showed the formation of a network‐like structure in samples containing the chemically treated kaolin as a result of improved dispersion of particles. It was also observed that both the kaolin particles and modifiers could accelerate the degradation process and lower the molecular weight of the PET. The introduction of kaolin particles shifted the crystallization temperatures of PET to higher temperatures. It was observed that the incorporation of a chain extender significantly restricted the crystallization process. The Avrami–Jeziorny analysis confirmed the alteration of the crystalline structure of the filled polymer. Based on TGA thermograms the decomposition temperature of PET–kaolin composites was slightly lower than that of the neat PET. POLYM. COMPOS., 37:1443–1452, 2016. © 2014 Society of Plastics Engineers