Transport properties of methanol in blends of a liquid crystalline copolyester and polyethersulfone

Abstract

Data for the diffusivity and solubility of methanol in blends of polyethersulfone (PES) and a liquid crystalline copolyester (polyhydroxy‐benzoic acid (73 mol%)‐co‐hydroxy‐naphthoic acid (27 mol%)) (LCP) are reported. Samples taken from injection molded and compression molded specimens over a wide composition range were studied by gravimetry (sorption and desorption), dielectric spectroscopy, differential scanning calorimetry and scanning electron microscopy. The sorption of methanol in PES led to the formation of an ordered phase. The sorption curves were S‐shaped and they could be described by a diffusion model assuming a concentration‐dependent diffusivity and time‐dependent boundary conditions. The solubility of methanol in the blends was strictly proportional to the PES content. The zero‐concentration‐diffusivity decreased strongly with increasing LCP content and it was dependent on the morphology. Injection molding yielded samples with a fibrillar LCP phase with a greater continuity of the PES component and a high diffusivity (in relative terms). Compression molding led to samples with a more continuous LCP component even at low LCP contents and a low diffusivity.

Solvent sorption effects on the structure and properties of PP/Rodrun blends

“…In the case of another thermoplastic/LCP blend, 8 in which the difference between the ␣ of the matrix and that of the LCP was lower than that of this work, there was not increased sorption. Moreover, in the case of PP filled with talc, 28 the sorption increase did not take place, probably due to the small talc particle size.…”

“…Even more relevant was the fact that desorption became slower than sorption at times larger than 22 h for PP in Tol, for example. Structural changes such as crystallization, 29 ordering, 8,32,33 or change of morphology induced by swelling 22 are often seen as a consequence of sorption. Given the lack of specific volume change due to sorption in PP and that the amorphous phase is above its T g , the large difference between desorption and sorption may be attributed to a morphology change of the amorphous phase or to a reordering of the crystalline phase during the sorption/desorption processes.…”

“…Permeability measurements to some gases have been carried out on extruded blown films of poly(ethylene terephthalate) (PET)/ Rodrun (Ro) blends. 6,7 The diffusivity and solubility of methanol on poly(ether sulfone) (PES)/Vectra blends 8 have also been studied. Among thermoplastics, an important number of works have been devoted to the interaction between fluids and polypropylene (PP).…”

Reinforced poly(ether sulfone) materials by blending with a semiaromatic liquid crystalline copolyester

“…With respect to PES/LCP blends, PES/VA, [11][12][13][14] PES/KU9231, [15][16][17][18][19][20] PES/Vectra B (VB), 21 PES/copolyester LCP, 22 PES/copolyesteramide LCP, 22 PES/R5, 23 and PES/aromatic copolyesters 9,24 blends were studied. Other articles on PES/LCP blends studied the transport properties of methanol in the blends 25 and measured the interfacial tension by different methods. 12,26 Both extruded 9,18,19,21,22,24 and injectionmolded [13][14][15]22 PES-based blends were studied.…”

“…The LCPs used in most of these studies were VA [11][12][13][14]25,26 and KU9231. [15][16][17][18][19][20] Both LCPs are fully aromatic copolyesters.…”