Photografting Of Methacrylic Acid Research Articles

Improvement of Adhesive Strength of Poly(tetrafluoroethylene) Plates through Oxygen Plasma Treatment and Subsequent Photografting of Methacrylic Acid

Methacrylic acid (MAA) was grafted onto the surface of a poly(tetrafluoroethylene) (PTFE) plate by the combined use of the plasma treatment and photografting, and the adhesive strength between the MAA-grafted PTFE (PTFE-g-PMAA) plates with the same grafted amounts was investigated in relation to the location of grafting as well as the wettability and water absorptivity. The grafted amount at which the substrate breaking occurred at lower grafted amounts for the PTFE-g-PMAA plates prepared by the plasma treatment for shorter times before the photografting and by the photografting at higher monomer concentrations and/or at lower monomer concentrations after the plasma treatment. These grafting conditions are found to be factors affecting the location of photografting, the thickness and water absorptivity of the grafted layer, and wettability of the surface of the grafted layer. The substrate breaking was observed at the minimum grafted amount (about 2.2 µmol/cm2) for the PTFE-g-PMAA plates prepared at 2.0 M and 60°C after the plasma treatment for 10 s and at 2.0 M and 40°C after the plasma treatment for 120 s. The obtained results support that the combination of the oxygen plasma treatment with photografting of MAA is an effective procedure to enhance the adhesivity of the PTFE surface.

Photografting of Methacrylic Acid onto Plasma-pretreated Poly(tetrafluoroethylene) Plates and Enhancement of Their Adhesivity

Photografting of Methacrylic Acid onto Plasma-pretreated Poly(tetrafluoroethylene) Plates and Enhancement of Their Adhesivity

Estimation of surface properties of grafted layers formed on low‐ and high‐density polyethylene plates by photografting of methacrylic acid and acrylic acid at different monomer concentrations and temperatures

AbstractAn investigation was carried out on estimation of hydrophilicity, wettability and water‐absorptivity, and surface analysis by X‐ray photoelectron spectroscopy of the low‐ and high‐density polyethylene (LDPE and HDPE) plates photografted with methacrylic acid (MAA) and acrylic acid (AA) at different monomer concentrations or temperatures. Wettability of the MAA‐grafted LDPE and HDPE plates increased with grafted amounts, and became constant when the substrate surfaces were fully covered with the grafted polymer chains. On the other hand, for the AA‐grafted LDPE and HDPE plates, wettability had the maximum value, and then gradually decreased against the grafted amount probably due to aggregation of grafted PAA chains, although the surfaces were covered with grafted PAA chains at lower grafted amounts compared with grafted PMAA chains. Water‐absorptivity sharply increased at lower grafted amounts due to formation of shorter grafted polymer chains for photografting at lower monomer concentrations or due to restriction of the location of grafting to the outer surface region for photografting at lower temperatures. Therefore, for photograftings of AA or onto the HDPE plates, the substrate surfaces were covered with grafted polymer chains and the grafted layers formed possessed higher water‐absorptivity at lower grafted amounts. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Effect of acid and pH value on the photografting initiated by aliphatic ketones in aqueous solutions

AbstractThe photografting of methacrylic acid (MAA) onto high‐density polyethylene (HDPE) initiated by aliphatic ketones (acetone, butanone, and cyclohexanone) in aqueous solutions with different pH values adjusted by adding different amount of mineral acids was reported. Acids significantly enhanced the photografting yield, and the extent of grafting generally increased with decreasing pH value. The effect of pH value on the grafting reactions varied with the acid used. The grafting of MAA onto HDPE surface was confirmed with FTIR and SEM characterizations. The water absorbency of the grafted p‐MAA varied with the extent of grafting. When the extent of grafting was less than 2000–3000 μg/cm2, grafted p‐MAA absorbed about 25–30% water, whereas at higher extent of grafting, it absorbed about 50% water. The mechanism of the acid enhancement of the photografting of MAA initiated by aliphatic ketones in aqueous solutions is believed to be attributed to the change of the solubility of monomer in the solution and the conformation of grafted chains, both are favorable for accelerating grafting reactions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

EFFECT OF MIXED SOLVENTS CONSISTING OF WATER AND ORGANIC SOLVENT ON PREPARATION OF MEDIUM-RESPONSIVE GRAFTED CELLULOSE FILM BY MEANS OF PHOTOGRAFTING

Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Cellulose having a medium-responsive function were synthesized by photografting of methacrylic acid (MAA) on regenerated cellulose film (thickness = 20 µm) at 60°C using mixed solvent consisting of water and organic solvents such as acetone and methanol. Xanthone was used as photoinitiator by coating on the film surfaces. A maximum percentage of grafting was observed at a certain concentration of organic solvent. MAA-grafted cellulose films produced showing homogeneous distribution of grafted chains, which was examined by scanning electron icroscopy. The modified films also exhibit medium responsive character, it shrinks in acidic and swells in basic solution. Moreover, the grafted film exhibited the ability to absorb copper ion, which was not influenced by the solvent used in grafting processes. Keywords: Photografting, mixed-solvent, regenerated cellulose film, methacrylic acid, pH-responsive character, absorption of cupric ion

Photografting of methacrylic acid onto HDPE initiated by acetaldehyde in aqueous solutions

Acetaldehyde could act as a very effective photoinitiator for water-borne photografting. The photografting of methacrylic acid (MAA) onto polyethylene initiated by acetaldehyde in aqueous solutions was reported. Acetaldehyde had higher photoinitiation efficiency than acetone and formaldehyde. The extent of grafting varied with the acetaldehyde content in the solution and it showed the maximum when the content of acetaldehyde was about 10 w/w %. The extent of grafting firstly increased with the increase of monomer concentration till 2 mol/L and then kept constant or slightly decreased. ATR-FTIR characterizations of the grafted samples proved the successful grafting of MAA onto PE, and the calculated carbonyl indexes were in accord with the results obtained by the gravimetric method. The water absorbency of the grafted samples increased almost linearly with the extent of grafting. The difference in the photoinitiation efficiencies of acetaldehyde, acetone and formaldehyde was discussed through their differences in the n-π* transitions in water and the photoinitiation process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Photografting of methacrylic acid onto hydroxyapatite particles surfaces

The unsaturated functional groups (CC) were introduced onto hydroxypatite (HAP) particles surfaces by esterification reaction between hydroxyl groups on the HAP surface and methacrylic acid (MAA). Then, graft polymerization of MAA onto the esterified HAP particles surfaces was carried out by ultraviolet light (UV) initiation. The structure of the surface-esterified and grafted HAP was studied by ESCA, FTIR, Scanning Electron microscopy, laser particle sizes analyze, esterification, and graft degrees tests. The results show that poly(methyl acrylic acid) (PMAA) is successfully inserted onto HAP particles surfaces by covalent bond linkage. The esterification degree between MAA and HAP particles increases with reaction temperature and time, and tends to level off at about 6 h under 90°C. The graft degree of MAA onto HAP particles with 1.14% esterification degree and its average particle sizes increase with UV initiation polymerization time, and to reach a maximum at 25 min under 40°C, then decrease as irradiation time further increases. The surfaces of the grafted HAP particles become rough and loose. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Aliphatic Ketones as Photoinitiators for Photografting

AbstractSummary: The photografting of methacrylic acid (MAA) onto high‐density polyethylene (HDPE) initiated by butanone, pentan‐3‐one, and heptan‐3‐one is presented. These aliphatic ketones can act as photoinitiators for photografting when they are a component of a suitable solvent mixture with water and ethanol. It is possible that the photoinitiation effect of the aliphatic ketone is induced by the hydrogen bond formed between it and water.The grafting of 2 M MAA in different ketone/water/ethanol (30/30/40) solvents.imageThe grafting of 2 M MAA in different ketone/water/ethanol (30/30/40) solvents.

Examination of the role of oxygen in the photografting of methacrylic acid on a polyethylene film with a mixed solvent consisting of water and organic solvents

AbstractThe photografting of methacrylic acid (MAA) on a linear low‐density polyethylene film (thickness = 30 μm) under air and nitrogen atmospheres was investigated at 60°C in mixed solvents consisting of water and an organic solvent, with xanthone as a photoinitiator. The organic solvents used were acetone, methanol, tetrahydrofuran, and dioxane. A maximum percentage of grafting occurred at a certain concentration of the organic solvent in the mixed solvent. This was observed for the systems under both air and nitrogen. The grafting reaction under air exhibited an induction period, but the rate of grafting after the period was greater than that under nitrogen. The formation of poly(ethylene peroxide)s by photoirradiation seemed to be a factor for the accelerated photografting under air. On the basis of attenuated total reflection infrared spectroscopy and scanning electron microscopy of the grafted film, the MAA‐grafted chains of the sample prepared under air tended to penetrate more deeply inside the film than those of the sample prepared under nitrogen. The resulting grafted films exhibited a pH‐responsive character: the grafted films shrank in an acidic medium but swelled in alkaline medium. This was evaluated from measurements of dimensional changes in the grafted films. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 992–998, 2003

Photografting of methacrylic acid on polyethylene film: Effect of mixed solvents consisting of water and organic solvent

AbstractPhotografting of methacrylic acid (MAA) on linear low‐density polyethylene film (thickness = 30 μm) was investigated at 60°C in mixed solvents consisting of water and organic solvent with xanthone as the photoiniator. The organic solvents examined were acetone, methanol, tetrahydrofuran, and dioxane. A maximum percentage of grafting was observed at a certain concentration of organic solvent in the mixed solvent, depending on the nature of the organic solvent. Distribution of the grafted chains in the resultant MAA‐grafted film, which was examined by scanning electron microscopy and attenuated total‐reflection IR spectroscopy, was largely influenced by the use of the mixed solvent. The grafted samples swelled in the alkaline region and shrank in acidic medium, showing a pH‐responsive character. The extent of the pH‐responsive function was closely related to the location of grafted chains, which could be controlled by proper choice of the composition of organic solvent in the mixed solvent. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2454–2461, 2002

Effect of monomer concentration on characteristics of methacrylic acid-grafted polyethylene film prepared by photografting

The effect of monomer concentration on photografting of methacrylic acid (MAA) onto linear low-density polyethylene (PE) film (thickness=30 μm) was investigated at 60 °C in water solvent together with the location of MAA-grafted chains. Xanthone was used as a photoinitiator which was coated on the film sample earlier. The higher percentage of grafting and graft efficiency were afforded for the system with the higher monomer concentration. The resultant MAA-grafted films were subjected to measurements of pH-responsive character and ability to adsorb cupric ion in order to understand the characteristics of function introduced. The grafted samples exhibited the pH-responsive character, where they shrank and swelled in acidic and alkaline media, respectively. The pH-responsive character of the grafted films was higher for the samples prepared in the system with a higher monomer concentration. Moreover, the grafted samples exhibited the ability to adsorb cupric ion, and the ability was reduced when the sample was prepared in the system with a higher monomer concentration. The different extents of the pH-responsive character and ability to adsorb cupric ion of the resulting grafted PE films were discussed in terms of location of grafted chains in the film substrate, which was determined by a scanning electron microscope and an attenuated total reflection infrared spectroscopy.

Effect of ethylene glycol dimethacrylate derivatives on photografting of methacrylic acid on low-density polyethylene

Abstract Photografting of methacrylic acid (MAA) on low-density polyethylene (PE) film (thickness=30 μm), on which xanthone photoinitiator was coated earlier, was investigated at 60°C in the presence of ethylene glycol dimethacrylate derivatives (EGDMA) with different numbers of ethylene glycol unit between two double bonds in the molecule, such as di-, tetra- and nona-ethylene glycol dimethacrylates (2EG, 4EG and 9EG, respectively). Addition of the EGDMA (0.3–3 mol% of MAA used) to the grafting system largely accelerated the photografting and the magnitude of the enhancement decreased in the order of 9EG>4EG>2EG. EGDMA component was incorporated into MAA-grafted PE films and the content decreased in the order of 2EG>4EG>9EG. MAA-grafted chains of the grafted PE films (sample with EGDMA) prepared by photografting in the presence of EGDMA tended to appear at the film surface compared to those of the grafted films (sample without EGDMA) prepared in the system without EGDMA, which was measured by electron probe microanalysis and attenuated total reflection infrared spectroscopy. The MAA-grafted PE films exhibited a pH-responsive character, which was evaluated by measuring a dimensional change of the grafted films. The grafted films shrank in acidic media, but swelled in alkaline media. The sample with EGDMA showed a larger pH-responsive character than the sample without EGDMA though there was no large difference in the character among EGDMA. The phenomenon was discussed in terms of the MAA-grafted chains with a branched structure, which was suggested by differential scanning calorimetry of the grafted films.

Surface Modification and Autohesive Properties of Poly(tetrafluoroethylene) and Polyethylene by the Photografting Technique.

Poly(tetrafluoroethylene) (PTFE) and low and high density polyethylene (LDPE and HDPE) plates were surface-modified by the photogafting of methacrylic acid (MAA) using a 400W high pressure mercury lamp. The autohesive strengths for MAA-grafted PTFE, LDPE and HDPE plates were estimated from the tensile shear strength measurements and their autohesive properties were discussed in relation to surface and bulk properties of the grafted layers formed on their substrates. The contact angles which were related with the wettabilities of the modified surfaces increased with an increase in the grafted amount, and then leveled off when the surfaces were wholly covered with grafted PMAA chains. The wettabilities for grafted PTFE plates were improved at a considerably low grafted amount, since the photografting of MAA onto the PTFE plates was most restricted to the outer surface region among the three types of substrates used in this study. The grafted LDPE and HDPE plates possessed high water-absorptivities. The autohesive strengths for grafted PTFE plates immersed in water reached the value equivalent to their adhesive ones. For the grated PTFE plates immersed in an aqueous HCl solution of pH 3 in place of water, the autohesive strength sharply increased in the range of lower grafted amounts. These results suggest that an increase in the autohesive strength can be caused not only by the entanglements of grafted PMAA chains but also by the formation of hydrogen bonding between carboxyl groups affixed to the grafted PMAA chains. On the other hand, in the case of the autohesive strength measurements for Grafted LDPE and HDPE plates, the substrate breaking occurred at higher grafted amounts. The grafted amount at which the substrate failed for grafted HDPE plates was lower than that for grafted LDPE plate because the photografting onto the HDPE plates was more restricted to the outer surface region. It was made clear that the autohesive strength for grafted PTFE plates reached the value equivalent to the autohesive strength and the autohesive strengths for grafted LDPE and HDPE plates exceeded the ultimate tensile strength by heat-pressing the grafted samples with the grafted layers swollen in water.

Photografting of methacrylic acid on low-density polyethylene film in presence of polyfunctional monomers

Photografting (λ > 300 nm) of methacrylic acid (MAA) on low-density polyethylene (PE) film (thickness = 30 and 60 μm), on which xanthone photoinitiator was coated earlier, was investigated at 60°C in the presence of polyfunctional monomers such as N,N′-methylenebisacrylamide (MBAAm) and trimethylol propane triacrylate (TMPTA). Addition of the polyfunctional monomers (0.01 and 0.1 wt %) to the grafting system largely accelerated the photografting, and the magnitude of the enhancement was larger for TMPTA than MBAAm. MBAAm component was incorporated into PE substrate and/or MAA-grafted chains through the grafting reaction. Double bonds of the introduced polyfunctional component seemed to act as a new site for the grafting initiation, leading to the promoted grafting. The polyfunctional monomer did not affect distribution of the grafted chains in the cross section of the resultant MAA-grafted film, which was measured by electron probe microanalysis. Wettability of the MAA-grafted PE film was not influenced by the addition of MBAAm, but water absorbency was reduced by using a higher concentration of MBAAm. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1635–1641, 1997

Photografting of methacrylic acid on low‐density polyethylene film in presence of polyfunctional monomers

Photografting of methacrylic acid on low‐density polyethylene film in presence of polyfunctional monomers

Factors Affecting Vapor-Phase Photografting of Methacrylic Acid on Low-Density Polyethylene Film

Abstract Factors affecting photografting (λ > 300 nm) of methacrylic acid on a low-density polyethylene film (thickness = 70 μm) were investigated in a vapor-phase system. Xanthone was coated on the film. Factors examined were pressure of the system (1, 20, and 50 mmHg), polymerization temperature (40, 50, and 60°C), and use of monomer mixed with water. It was found that the grafting rate decreases in the following order: 1 mmHg > 20 mmHg > 50 mmHg at 60°C, and 60°C > 50°C > 40°C under 1 mmHg pressure. The rate was sharply reduced by using monomer mixed with water (monomer/water = 1/1). The contact angle of water on the grafted films largely depended on the grafting conditions, decreasing in the same order as that of the grafting rate described above. Thus, higher wettability was recorded for grafted films prepared under grafting conditions where the grafting rate is slow. The resultant grafted chains are supposed to localize mainly on the film surface.

Effects of diphenylamine and binary sensitizers on photografting of methacrylic acid on low-density polyethylene film

Photografting of methacrylic acid on low-density polyethylene film (thickness = 30 μm) in aqueous medium was examined at 60° using diphenylamine (DPA) as sensitizer previously coated on the film. DPA as well as triphenylamine acted as photofragmenting initiator for the grafting and gave higher extent of grafting and lower formation of homopolymer than triphenylamine. Binary sensitizers, composed of DPA and acceptors such as tetracyanoethylene, 7,7,8,8-tetracyano-quinodimethane, p-chloranil and maleic anhydride, led to higher extent of grafting and lower yield of homopolymer than DPA alone. DPA and acceptor seemed to form a 1 : 1 complex according to study of u.v. spectra. It was found that photografting using the binary sensitizers proceeds effectively through the formation of complex between DPA and acceptor, and that the binary sensitizers are useful for enhancing the ratio of grafted polymer to homopolymer.

Effect of hydroquinone on location of methacrylic acid‐grafted chains introduced into polyethylene film by photografting

AbstractEffect of hydroquinone (HQ) on photografting of methacrylic acid (MAA) on low‐density polyethylene film (thickness = 30 μm) sensitized with xanthone was investigated at 60°C in water medium. Both the formation of grafted polymer and homopolymer were retarded by HQ. The contact angle of water on the MAA‐grafted polyethylene films (sample with HQ) prepared in the system with HQ was larger than that of the grafted films (sample without HQ) prepared in the system without HQ. Based on electron probe microanalysis of the grafted films, it was found that distribution of grafted chains in the direction of film thickness is different between the both grafted films. Namely, the grafted chains of the sample with HQ distributed in the inside of the film compared with those of the sample without HQ. The difference in the distribution of grafted chains between the grafting systems with and without HQ was discussed in terms of effect of HQ on the photodecomposition of MAA‐grafted chains and the subsequent initiation of polymerization by radicals due to the photodecomposition.

Benzil‐sensitized photografting of methacrylic acid on low‐density polyethylene film

Mesures comparees des pourcentages, de greffage et d'homopolymere et de la mouillabilite des films de copolymeres obtenus par greffage photosensibilise par le benzile, la benzophenone et le benzoine ethyl ether (BEE). Le benzile, tout comme le BEE favorise la formation de l'homopolymere

Effect of carbazole/tetracyanoethylene binary sensitizer on photografting of methacrylic acid on polyethylene film

Effect of carbazole (CZ)/tetracyanoethylene (TCE) binary sensitizer on photografting of methacrylic acid on low-density polyethylene film (thickness = 30 μm) was examined at 40° and 60° in aqueous medium. Based on the study of absorption spectra, CZ and TCE seemed to form a 1:1 complex, appearing at 400 and 600 nm in the spectra. The system sensitized with CZ/TCE binary sensitizer showed higher percent grafting and graft efficiency than the CZ-sensitized system. Moreover, a certain composition of the binary sensitizer most effective for grafting was found; this composition was about 30 mol% of TCE in the binary sensitizer, at which maxima of percent grafting and graft efficiency were afforded. This behaviour of CZ/TCE-sensitized photografting was discussed in terms of formation of a charge transfer complex between CZ and TCE and formation of polyethylene radicals caused by the binary sensitizer.