Surface Modification of PVC Membranes Using Fluorothiophenol Compounds

Abstract

The controlled chemical surface modification of PVC films by means of three fluoride aromatic compounds, 4‐fluoro thiophenol, 3,4‐difluorothiophenol and penta fluorothiophenol is reported. To obtain information about the surface selectivity of the reactions, the degree of modification of the polymer across the film was determined by depth profiling carried out using confocal Raman microscopy. It is shown that the gradient of the modification degree and the surface selectivity depend on the relationship between the rate constants of the substitution reaction and the diffusion process of the reactant. Therefore it is function of reaction time, temperature and the proportion of solvent/non‐solvent used for the reaction.magnified image

Covalent Functionalizations of Poly(vinyl chloride) in Tune with Applications: An Update

“…According to a specific separation, PVC was covalently modified by an adequate functionalization. Spanish school [27][28][29] reported on bulk and surface functionalization of PVC with fluorothiophenol entities. PVC with a molecular weight of M w = 112 000 g/mol underwent bulk functionalization with fluorothiophenyls via nucleophilic substitution reaction with 4fluorothiophenol (PVC-1F), 3,4-difluorothiophenol (PVC-2F), and pentafluorothiophenol (PVC-5F), in cyclohexanone at 60 °C and in the presence of potassium carbonate.…”

“…The highest conversion degree for the former process was nearly 23% at 60 °C and two days and that for the latter one was about 46% at 80 °C and for 30 min. In the thermal process, both substitution and elimination mechanisms occurred as suggested by the (26) (27) (28) bimodal curve of the elution profile from GPC measurement (gel permeation chromatography). Molecular weights M w of the PVC-3TTA's were lower than that of virgin PVC: 28 900 g/mol (thermal process), 35 600 g/mol (microwave-assisted process) against 56 991 g/mol; the polydispersity index (microwave-assisted process) was higher than that of PVC, 3.8 against 1.7.…”

Low protein fouling polypropylene membrane prepared by photoinduced reversible addition‐fragmentation chain transfer polymerization

“…For membranes, the surface properties are as important as their bulk properties, but it is often difficult to find a material that provides a suitable combination of both. To solve this problem, surface modification has been widely used to enhance the membrane performance such as flux and selectivity without changing the bulk properties 1–3. Membrane surface modification is an important area for both applied and basic research.…”

“…To solve this problem, surface modification has been widely used to enhance the membrane performance such as flux and selectivity without changing the bulk properties. [1][2][3] Membrane surface modification is an important area for both applied and basic research. A number of surface modification techniques such as plasma treatment, photoinduced graft were adopted, most of which are via the traditional free-radical polymerization process.…”