SYNOPSISPoly (acrylic acid) ( PAAc) films were treated with either a n argon or a tetrafluoromethane (CF,) plasma and subsequently analyzed with X-ray photoelectron spectroscopy (XPS). PAAc films were decarboxylated during both types of plasma treatments. In addition, during the CF4 plasma treatment, the PAAc films became fluorinated. The plasma phase during the argon plasma treatment of PAAc films was investigated with optical emission spectroscopy. It was shown that during this plasma treatment carbon dioxide, water, and possibly hydrogen were liberated from the PAAc surface. By covering the surface of PAAc films with different materials (lithium fluoride, UV fused silica, and glass) during the plasma treatment, it was possible to differentiate between photochemically induced and particleinduced changes of the surface. This method was used to show that decarboxylation during the argon plasma treatment was caused by vacuum UV radiation (wavelength < 150 nm) and the decarboxylation/ fluorination during the CF4 plasma treatment was induced by reactive fluorine-containing species from the plasma phase. Furthermore, during both processes, etching of the PAAc surface occurred. Based on these mechanisms, kinetic models were derived that could be used to describe the measured kinetic data adequately. 0 1994

Glycine/glycolic acid based biodegradable copolymers have been prepared by ring‐opening homopolymerization of morpholine‐2,5‐dione, and ring‐opening copolymerization of morpholine‐2,5‐dione and glycolide. The homopolymerization of morpholine‐2,5‐dione was carried out in the melt at 200°C for 3 min using stannous octoate as an initiator, and continued at lower reaction temperatures (100–160°C) for 2–48 h. The highest yields (60%) and intrinsic viscosities ([η] = 0.50 dL/g; DMSO, 25°C) were obtained after 3 min reaction at 200°C and 17 h at 130°C using a molar ratio of monomer and initiator of 1000. The polymer prepared by homopolymerization of morpholine‐2,5‐dione was composed of alternating glycine and glycolic acid residues, and had a glass transition temperature of 67°C and a melting temperature of 199°C. Random copolymers of glycine and glycolic acid were synthesized by copolymerization of morpholine‐2,5‐dione and glycolide in the melt at 200°C, followed by 17 h reaction at 130°C using stannous octoate as an initiator. The morphology of the copolymers varied from semi‐crystalline to amorphous, depending on the mole fraction of glycolic acid residues incorporated. © 1994 John Wiley & Sons, Inc.

Gas plasma treatment of poly(ethylene terephthalate) nonwoven (NW-PET) was used to increase the hydrophilicity of single-and multilayer NW-PET. NW-PET was treated with a pulsatile CO 2 or with a pulsatile H 2 O glow discharge. X-ray photoelectron spectroscopy (XPS) showed significantly more oxygen with CO 2 glow-discharge-treated NW-PET than with H 2 O glow-discharge-treated-NW-PET surfaces. Moreover, the introduction rate of oxygen at a single layer of NW-PET was higher for a CO 2 than for a H 2 O glow-discharge treatment. Titration data revealed significantly higher surface concentrations of carboxylic groups for CO 2 glow-discharge NW-PET than for H 2 O glow-discharge-treated NW-PET. Mass spectrometry analysis revealed that the entire internal surface of a single layer of NW-PET was modified. XPS and contact measurements confirmed the modification of the internal surface of multilayers of NW-PET. H 2 O and CO 2 glow-discharge-treated substrates consisting of six layers of NW-PET had a nonuniform surface concentration of carboxylic acid groups as determined with titration experiments. The outside layers of the substrate contained a higher surface concentration of carboxylic acid groups than did the inside layers. XPS analysis and titration data showed that the rinsing of H 2 O and CO 2 glow-dischargetreated NW-PET with water changed the surface composition considerably. Part of the carboxylic acid group-containing species were washed off.

Gas plasma treatment of poly(ethylene terephthalate) nonwoven (NW-PET) was used to increase the hydrophilicity of single-and multilayer NW-PET. NW-PET was treated with a pulsatile CO 2 or with a pulsatile H 2 O glow discharge. X-ray photoelectron spectroscopy (XPS) showed significantly more oxygen with CO 2 glow-discharge-treated NW-PET than with H 2 O glow-discharge-treated-NW-PET surfaces. Moreover, the introduction rate of oxygen at a single layer of NW-PET was higher for a CO 2 than for a H 2 O glow-discharge treatment. Titration data revealed significantly higher surface concentrations of carboxylic groups for CO 2 glow-discharge NW-PET than for H 2 O glow-discharge-treated NW-PET. Mass spectrometry analysis revealed that the entire internal surface of a single layer of NW-PET was modified. XPS and contact measurements confirmed the modification of the internal surface of multilayers of NW-PET. H 2 O and CO 2 glow-discharge-treated substrates consisting of six layers of NW-PET had a nonuniform surface concentration of carboxylic acid groups as determined with titration experiments. The outside layers of the substrate contained a higher surface concentration of carboxylic acid groups than did the inside layers. XPS analysis and titration data showed that the rinsing of H 2 O and CO 2 glow-dischargetreated NW-PET with water changed the surface composition considerably. Part of the carboxylic acid group-containing species were washed off.