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.

Surface characterization of 1-butyl-1-ethylpiperidinium bromide by inverse gas chromatography

“…based on the high values of the regression coefficients. Similar plots for the estimation of the Z [ and Z \ constants appear in literature[27,51,62,68]. The results of the acidity and basicity constants of the surface of [C 2 C 4 PIP]Br are reported in Table6.…”

“…Physical and chemical properties of the probes used for the IGC analysis[27,[47][48][49][50][51][52] …”

Octyl Co‐grafted PrSO3H/SBA‐15: Tunable Hydrophobic Solid Acid Catalysts for Acetic Acid Esterification

“…Inverse gas chromatography (IGC) is a powerful technique to probe the surface apolar and polar interactions of materials with adsorbates at a molecular level . IGC measurements thus allow surface–adsorbate interactions to be investigated on porous catalysts, with thermodynamic properties including surface energy, hydrophobicity acid–base properties, heat of adsorption, and specific free energy to be determined.…”

Fluorinated graphite reinforced polytetrafluoroethylene/poly(butylene terephthalate) composites as friction materials for deep‐sea applications

“…In principle, polymers can be transferred to metallic counterfaces, and this transfer ability is determined by the difference in surface energy between the friction couples 46 . The incorporation of FGr with an extremely low surface energy of 3.92 mJ/m 2 47 into PBT matrix of 41.6 ~ 42.3 mJ/m 2 48 increases the difference in surface energy, thereby improving the driving force for transfer. As a result, an improved occupied area and continuity of the transfer film are achieved even at high seawater pressures compared with those of neat PBT and the PTFE/PBT composite.…”