| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1199633 | Journal of Chromatography A | 2015 | 8 Pages |
•Poly(butylene terephthalate) was analysed by inverse gas chromatography.•The enthalpy of adsorption of polar molecules on PBT was found to be endothermic.•The crystallisation activation energy of PBT is dominated by the Lewis basic sites.•Weaker Lewis acid/base intra(inter)molecular forces lead to lower extent of crystallization in PBT.•The analysis of Ka and Kb is useful in the interpretation of the crystallinity of PBT.
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.
