Surface carboxylation of PEEK film by selective wet-chemistry

Surface carboxylated PEEK films were obtained from a common key-intermediate, the PEEK-OH film, resulting from the surface reduction of amorphous PEEK film. Substitution of the hydroxyl groups, under mild acidic conditions, with 4-aminobenzoic acid and succinamic acid gave PEEK-Ph-CO2H and PEEK-(CH2)(2)-CO2H in 38% and 70% yields, respectively. The sample surfaces were analysed by X-ray photoelectron spectroscopy. The reactivity of PEEK-(CH2)(2)-CO2H was assayed by activation with WSC, SOCl2 or CDI, followed by coupling to H-3-lysine and liquid scintillation counting of the radioactivity associated with the samples. (C) 1997 Elsevier Science Ltd

Surface functionalization of PEEK films using photochemical routes

Two photochemical routes have been considered for the surface topologically defined functionalization of poly(ether ether ketone) (PEEK) films, based, respectively, on the covalent coupling of molecules protected with a photoclivable group (indirect way A), and on the photografting of various azide derivatives (direct way B). (4,5-Dimethoxy-2-nitrophenyl)methyl succinamate 3 could be coupled to the PEEK-OH film surface, under wet-chemistry conditions, but in rather low yield. 4-Azido-benzoic acid 9,4-azido-tetrafluorobenzoic acid 6 and N-butyl-N'-(4-azidophenyl)thiourea 8 were grafted on the PEEK and PEEK-OH films surface, under mild photochemical conditions, in moderate to good yields. Attempts to obtain patterned surfaces with 4-azido-benzoic acid 9 and sodium 5-azido-naphthalene-1-sulphonate 10, under microlithographic conditions, failed. (C) 2000 Elsevier Science Ltd. All rights reserved

One-step hydroxy substitution of 4,4'-dimethoxybenzhydrol with amides, lactams, carbamates, ureas and anilines

A series of amides, lactams, carbamates, ureas and anilines, equipped with various functionalities, were readily N-alkylated with the 4,4'-dimethoxybenzhydryl residue by reaction with 4,4'-dimethoxybenzhydrol [bis(4-methoxyphenyl)methanol] in acetic acid, at room temperature, under H2SO4 catalysis

Effect of the chemical nature and length of spacer arms on the covalent grafting of fluorinated molecular probes at the surface of poly(ethylene terephthalate) membrane

A series of fluorinated molecular probes were synthesized that are characterized by spacer arms of various lengths and polarities. Previous molecules (1, 2a, 2b, 2c, 3a, 3b) were covalently fixed on the surface of poly(ethlylene terephthalate) (PET) membranes via activated hydroxyl chain endings. X-ray photoelectron microscopic analysis of the grafted samples allowed us to quantify the PET surface reactivity; the results were within 40-50 pmol/cm(2) of fixed probes, independent of the length and hydrophilicity of the spacer arms. (C) 2002 Wiley Periodicals, Inc

Emission of volatile organic compounds during processing and use of organoclay-based nanocomposites

International audienc

Surface reduction of poly(aryl ether ether ketone) film: UV spectrophotometric, H-3 radiochemical, and X-ray photoelectron spectroscopic assays of the hydroxyl functions

The surface reduction of amorphous poly(aryl ether ether ketone) (PEEK) film was successfully achieved by wet chemistry using a solution of NaBH4 in DMSO at 120 degrees C for 3 h. The resulting PEEK-OH film was fully characterized by MIR, W-visible, and H-1 NMR spectroscopies; all the data were consistent with those of the references, 4-(4-methoxyphenoxy)benzhydrol and bulk-reduced PEEK (''PEEK-OH''). The surface of PEEK-OH film was analyzed by X-ray photoelectron spectroscopy (XPS). From the fine structures of the Cls and Ols peaks, we could determine a ratio of reduction reaching 75-85% of the monomer units contained in the 10 outermost atomic layers. The surface reactivity of the hydroxyl groups was assayed by derivatization with [H-3]acetic anhydride followed by liquid scintillation counting (LSC) of the sample-associated radioactivity. The PEEK-OH film was reacted with p-nitrophenyl chloroformate to furnish an activated surface (PEEK-OCO2PNP), the basic hydrolysis of which allowed the indirect spectrophotometric assay of the reactive OH groups. The PEEK-OCO2PNP film was further used to covalently fix amine derivatives via a carbamate Linkage. Using [H-3]lysine and trifluoroethylamine, we were able to assay the surface reactivity by LSC and XPS respectively. The ratios of surface derivatization were within 5-30%. The PEEK-OH film was used as substrate for the cultivation of CaCo2 epithelial cells; the presence of surface hydroxyl functions moderately improves the polymer biocompatibility

Di[bis(4-methoxyphenyl)methyl]ether As Dehydration Product of 4,4'-dimethoxybenzhydrol Under Unusually Mild Conditions

4,4'-Dimethoxybenzhydrol 1b was readily dehydrated by the isocyanate reagent 5 to furnish di[bis(4-methoxyphenyl)methyl] ether 4b. This symmetrical ether was similarly obtained upon treatment of 1b with diethylaminosulfur trifluoride (DAST)

Covalent attachment of fluorescence probes on the PEEK-OH film surface

7-Amino-4-(trifluoromethyl)-coumarin and I-aminopyrene were fixed on the PEEK-OH film surface by direct substitution of the hydroxyl functions in acidic medium. The resulting materials, called PEEK-coumarin and PEEK-pyrene, were analyzed by XPS, ToF-SIMS and fluorescence spectroscopy. This last method was not suitable for quantitative assays. (C) 1999 Elsevier Science Ltd. All rights reserved

Characterisation of low-odour emissive polylactide/cellulose fibre biocomposites for car interior

Low odour-emissive polylactide/cellulose fibre biocomposites, intended for car interior, were prepared and characterised. The impact of the different stages of processing (drying cycles, compounding, injection moulding) on the extent of polylactide degradation and on biocomposites properties was investigated by size exclusion chromatography, thermogravimetry, differential scanning calorimetry. In parallel, the odour emission of these materials was quantified via dynamic dilution olfactometry and Field of odours (R) method. The changes in molecular weight and global odour emission indicated that compounding had a strong impact on polylactide degradation and odour emission, while injection moulding had no significant impact. Adding 0.5 wt% of an absorbent agent based on poly(1-methylpyrrol-2-ylsquaraine could) divide the global odour concentration by a factor 2. The morphology, mechanical and thermal properties of injection moulded PLA-biocomposites were not affected by the presence of the absorbent agent