title: Lewis acid/base character and crystallisation properties of poly(butylene terephthalate).
abstract: Two grades of poly(butylene terephthalate) were analysed by means of inverse gas chromatography (IGC) and the results correlated with the respective crystallisation properties. The following parameters were determined by IGC: the dispersive component of the surface tension, the enthalpy and the entropy of adsorption of selected polar and apolar probes, and the Lewis acidity and basicity constants, Ka and Kb respectively. The interpretation of the values determined for Ka and Kb is in agreement with the FTIR spectra relating to the carboxyl end-group and the hydroxyl end-group concentrations in these polymers. The differences in the molecular weight values and in the end-group type and concentration, between the two grades of PBT, do not cause differences in the crystallisation activation energy. This observation suggests that there is a leading contribution of the Lewis basic sites to the crystallisation activation energy of the grades of PBT that were analysed. However, the lower value of Ka and the greater molar mass of one of the PBT grades lead to a corresponding lower crystallisation degree.
authors.affiliation: Department of Colour and Polymer Science, School of Chemistry, The University of Leeds, Woodhouse Lane, Leeds, West Yorkshire LS2 9JT, United Kingdom. Electronic address: josesantos@ipb.pt.
authors.forename: José M R C A
authors.initials: JM
authors.lastname: Santos
authors.affiliation: Department of Colour and Polymer Science, School of Chemistry, The University of Leeds, Woodhouse Lane, Leeds, West Yorkshire LS2 9JT, United Kingdom.
authors.forename: James T
authors.initials: JT
authors.lastname: Guthrie
mesh_terms: D000327:Adsorption; D000475:Alkenes / Q000737:chemistry; D002849:Chromatography, Gas; D003460:Crystallization; D058116:Lewis Acids / Q000737:chemistry*; D058115:Lewis Bases / Q000737:chemistry*; D010795:Phthalic Acids / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D013500:Surface Tension; D013816:Thermodynamics
chemical_list: D000475:Alkenes; D058116:Lewis Acids; D058115:Lewis Bases; D010795:Phthalic Acids; D011108:Polymers; C558934:butylene; C011363:terephthalic acid
keywords: Crystallisation; Inverse gas chromatography; Lewis acid/base properties; Poly(butylene terephthalate)