Photo-initiated vapor-phase grafting of acrylic monomers onto fibrous substrates in the presence of biacetyl

Abstract

SynopsisA novel vapor-phase process has been developed for grafting relatively volatile acrylic monomers onto various polymeric substrates, using photo-initiation by near ultraviolet irradiation in the presence of biacetyl vapors. With it, very even graft polymerizations on the substrates, with minimum amounts of homopolymerization, were found. Furthermore, there were essentially no changes in the tensile or aesthetic properties of the treated surfaces. The degree of photografting is dependent upon the chemical composition and porosity of the substrate, the volatility and reactivity of the monomers, prewetting of the substrate with a suitable wetting agent, and the conditions of irradiation used. The effects of various reaction parameters on the photo-induced grafting of methyl acrylate, methyl methacrylate, and acrylonitrile on wool keratin are studied in detail. Increasing biacetyl and monomer flow rates and flow times, irradiation times, and moisture content of the wool all caused progressive increases in the amount of polymer grafted to the wool, up to limiting values dependent on the reaction parameters involved and monomer used. In all instances, the amount of homopolymer found on the fiber was limited and remained essentially constant over the range of conditions studied. A series of acrylic monomers of different volatilities and reactivities including methyl acrylate, methyl methacrylate, butyl acrylate, acrylic acid, acrylamide, acrylonitrile, N,N-dimethylaminoethyl methacrylate, and 2,2,2-trifluoroethyl methacrylate was successfully grafted onto several hydrophilic and hydrophobic textile fibers (wool, cotton, rayon; nylon, acrylics, polyester, and polypropylene) and other polymeric surfaces such as filter paper, cellophane, and acetate film by this process. The wetting agents used included water, methyl and n-propyl alcohol, N,N-dimethylformamide, dimethylsulfoxide, benzene, and chlorinated hydrocarbon solvents.

Photo-Induced Grafting of Monomers on Prewetted Fiber Substrates

“…Since a number of polymer substrates are adversely affected by short-wavelength ultraviolet irradiation, a rapid, higher wavelength (>300 nm), sensitized, vapor-phase grafting technique for polymer substrates would be desirable and might lead to an economically viable photografting process. In the course of our research into photografting on fiber surfaces, we obtained extremely even grafts of up to 20% polymer on pre-wetted surfaces when near UV light and biacetyl vapors were used to initiate graft polymerization using vapor-phase monomers (25). Inexpensive equipment that operates near atmospheric pressure with minimum radiation shielding was used in this photografting process.…”

Ultraviolet radiation‐induced graft copolymerization of 2‐hydroxyethyl methacrylate onto polypropylene

“…Different constant temperatures of reaction were maintained by using a thermostatically controlled glycerine bath. The substrate, placed in a quartz flask containing the grafting solution, was irradiated for different time intervals varying from 1 to 6 h in an enclosed wooden chamber containing the UV lamp, the distance between the lamp and the substrate being about 12 cm. The flasks were intermittently shaken.…”

Photografting of 2-methacryloyloxyethyl phosphorylcholine from polydimethylsiloxane: Tunable protein repellency and lubrication property

“…Photoinduced graft polymerization has been studied for more than five decades [1][2][3][4][5][6][7][8][9]. It involves polymerization of acrylic or vinyl monomers from reactive sites on a substrate toward bulk phases.…”