Adsorption of polyesters on glass, silica, and alumina

Abstract

The adsorption of se veral saturated , linea r polyesters has been studied under a varicty of conditions. The study also included di-n-butyl sebacate as a model low molecul ar weight ester and poly (met hyl m ethacrylate). The adsorbents were type E glass powder, silica, a nd a lumina. The glass powder and silica were nonporous materi als; t he alumina contained a lal'ge internal pore structure. The rate of adsorption of t he polyesters on glass was very ra pid and t he adsorpt on isotherm was irrevcrsible. Adsorption from a poor solven t was favored over adsorpt ion from a good solvent. A large number of sitcs a re available on t he adsorbent for bond format ion and the adsorbed polymer m ost proba bly extends into t he solution in a coiled configuration. Metallic ions, in a ddition to silicon , a ppear to be involved in a n electrostatic bond between t he polymer and t he glass. The Langmuir eq uation is obeyed at high-equilibrium co ncentrat ions, although t hcre is nonconformity at t he low concen trations.

Thickness of adsorbed polystyrene layers by ellipsometry

“…This finding was supported by rate experiments with the same type of polymer and surface [12]. The adsorption of polyesters on polar surfaces such as glass and silica showed that relatively small amounts were adsorbed for these systems, corresponding to 2 to 5 layers on the glass, depending on the solvent used, and to one layer on the silica, if the polymer molecule were considered to lie flat [13]. A study of the adsorption of butyl rubber and polyisobutylene on carbon black led the investigators to the conclusion that both long and short polymers lie flat on the external surface of the carbon black [14].…”

Physicochemical factors affecting flocculation of pre-reduced nickeliferous laterite suspension

“…Extended fundamental work has been carried out by various researchers mainly on mono-mineral systems as regards polymer dissolution and thermodynamics [3][4][5][6][7]. Other researchers studied flocculation kinetics [8][9][10][11] and agglomerate structure [12][13][14].…”

Reversibility of polyester adsorption on glass

“…Molecules of intermediate molecular weight are also of interest, but have not been extensively investigated. In previous work in this area, the adsorption of a series of relatively low molecular weight poly (ethylene glycols) on a porous carbon [1] 3 and of several polyesters with molecular weights of the order of 4000 on glass, silica, and alumina [2] has been studied. The adsorption isotherms for the polyesters were not nearly as steep at low concentrations as were those for higher molecular weight polymers; a plateau was not attained until relatively high solution concentrations were reached.…”

“…The adsorption-desorption behavior of potymer molecules has been of interest, in part, because of the information implied regarding the conformation of the polymer molecule and interactions with the surface. Polymer molecules have been reported to adsorb relatively rapidly [2, 3, 4, 5] on nonporous surfaces, although some recent measurements indicate that this is not necessarily so under all conditions [4, 6]. A recent theoretical treatment [7, 8] has concluded that times to equilibrium are long, caused in part by rearrangements of the molecule at the surface.…”

“…For some systems no desorption occurs within practical units of time (see, e.g., ref. [2]), while for others some desorption does occur [3, 5, 6]. In one study, Soxldet extraction removed only negligible amounts of polystyrene that had been adsorbed on carbon black [9].…”