Characteristics of methacrylic acid‐grafted polyethylene films prepared by photografting in the presence of polyfunctional monomers

Abstract

Photografting of methacrylic acid (MAA) on low-density polyethylene film (thickness ϭ 30 m), on which xanthone photoinitiator was coated earlier, in the presence of polyfunctional monomers such as N,NЈ-methylenebisacrylamide, ethylene glycol dimethacrylate, and trimethylol propane triacrylate was examined at 60°C in water/ acetone (3:1 v/v) mixture solvent. The photografting was retarded at the earlier stage of polymerization, and then accelerated when small amounts of the polyfunctional monomers (1-3 mol % of MAA monomer used) were added to the system. Addition of the polyfunctional monomers did not affect distribution of the grafted chains in the cross section of the resultant MAA-grafted PE film, which was measured by electron probe microanalysis. The MAAgrafted samples were subjected to adsorption of cupric ions at 25°C for 24 h in the system of pH ϭ 5. The adsorption was considerably suppressed for the grafted samples prepared at the earlier stage of polymerization in the system with the polyfunctional monomers. The phenomenon was discussed in terms of the formation of crosslinked and branched structures in the MAA-grafted chains depending on the polymerization stage in the system with polyfunctional monomers.

Surface photografting polymerization of trimethylolpropane triacrylate onto LDPE substrate in tetrahydrofuran/water mixtures

“…To date, however, most studies have focused on monofunctional monomer system, and few researches regarding the incorporation of multifunctional monomers have been reported. Kubota and coworkers11–14 photografted methyl acrylic acid and acrylic acid onto LDPE substrate, and found that addition of multifunctional monomers, for example, TMPTA, N,N′‐ methylenebisacrylamide, ethylene glycol dimethacrylate and its derivatives, could accelerate grafting considerably. Other works also revealed that grafting of monofunctional monomers onto polyolefin or cellulose surface could be promoted by addition of multifunctional monomers 15–17.…”

Adhesion of surface‐grafted low‐density polyethylene plates with enzymatically modified chitosan solutions

“…Surface modification of polyolefin materials by grafting techniques has been also widely investigated by many researchers. The grafting polymerization was initiated by plasma treatment14–17 or by irradiation with UV18–21 and Co 60 radiation 22‐26. Because the energy of UV rays emitted from a 400W high‐pressure mercury lamp used as an energy source of the photografting technique is lower than those of other grafting techniques, the location of grafting is restricted to the outer surface region of the polymer substrates and the surface properties are modified at lower grafted amounts.…”