Advances in Thermal Gradient Interaction Chromatography and Crystallization Techniques for Composition Analysis in Polyolefins

Abstract

Summary Since the introduction of high temperature interaction chromatography for the analysis of polyolefins the technique has demanded a particular interest in the analysis of elastomers where crystallization techniques will meet a limitation given the low crystallinity of these polymers. In this paper the introduction of non carbon adsorption supports such as molybdenum sulfide, boron nitride and tungsten sulfide with equivalent separation to graphitized carbon packing in TGIC analysis of polyolefins is presented. A mechanism for the separation of polyolefins by adsorption chromatography on layered substrates is proposed. The influence of solvent polarity in interaction chromatography is discussed.

Molecular Dynamics Simulation of Ethylene/Hexene Copolymer Adsorption onto Graphene: New Insight into Thermal Gradient Interaction Chromatography

“…A nearly symmetric peak confirms that all polymers were unimodal in composition. As observed by Soares, Cong, and Monrabal copolymers elute in the order of decreasing hexene content . The elution temperature of the nine copolymers were plotted against hexene mol% (see the inset in Figure ).…”

“…Monrabal and co‐workers showed that any packing material having atomically flat surface provided the same separation as graphitic column. They suggested that the adsorption strength depends on the available surface area of the molecule (i.e., the length of the ethylene segments) in contact with the flat support surface . The adsorption is based on weak van der Waals forces interaction between nonpolar polyolefin and an atomic level flat surface.…”

“…The adsorption is based on weak van der Waals forces interaction between nonpolar polyolefin and an atomic level flat surface. Increasing the α‐olefin fractions (i.e., shortening the ethylene segments) hinders this interaction thus lowering the desorption temperature . They have also reported that the elution temperature is independent of the polymer molar mass above a 25 000 g mol −1 threshold .…”

Separation of bimodal high density polyethylene using multidimensional high temperature liquid chromatography

“…Prabhu et al / J. Chromatogr. A xxx (2015) xxx-xxx in SEC of ethylene/1-alkene copolymers [14,64,[98][99][100]. Only a few IR-transparent solvents (C-H absorbance) exist: TCB, ODCB, TCE and 1-chloronapthalene.…”

Effect of Solvent Type on High‐Temperature Thermal Gradient Interaction Chromatography of Polyethylene and Ethylene–1‐Octene Copolymers

“…Moreover, they combined TGIC and CEF to form a cross‐fractionation instrument with enhanced peak separation. They also reported that other support types, such as molybdenum sulfide, boron nitride and tungsten sulfide, could also be used to fractionate polyolefins by HT‐TGIC …”