Surface Photografting Polymerization of Binary Monomers Maleic Anhydride and n-Butyl Vinyl Ether on Polypropylene Film I. Effects of Principal Factors

Abstract

ABSTRACT:Maleic anhydride (MAH) was grafted onto polypropylene (PP) film efficiently by means of introducing the electron donor monomer n-butyl vinyl ether (n-BVE), under UV irradiation. The principal factors affecting surface photografting polymerization such as irradiation time, molar ratio of MAH to BVE, monomer concentration, photoinitiators, UV and solvents, were investigated systematically. The results show that the photografting of MAH/BVE is an effective approach to modify the surface property of the polymeric materials, and the photografting process is very efficient. The contact angle of the grafted surface against water could decrease from 87• to less than 20 • within 40 s of the irradiation time. The grafting efficiency would reach the highest when the molar ratio of MAH to BVE was 1:1, which indicated that the formation of charge transfer complex (CTC) between the binary monomers was favorable to the photografting polymerization. Among the photoinitiators benzildimethylketal (BDK), benzophenone (BP) and isopropylthioxanthone (ITX), the sequence of grafting efficiency was BP>ITX>BDK. Far UV (200-300 nm) radiation played a decisive role in the photografting polymerization and high UV intensity could accelerate this process. The solvent with good affinity towards the substrates was favorable to increase the grafting efficiency, because the diffusion of monomer and photoinitiator to the liquid-solid interface could be swimmingly. FT-IR spectra confirmed that both MAH and BVE had been successfully grafted onto PP film.

Surface Graft Polymerization of Binary Monomers Maleic Anhydride/n-Butyl Vinyl Ether on the Polypropylene Film via Two-Step Method

“…In the UV pre-irradiation step, both the apparatus and the operation were just like those in the photografting process, 13,19 except that only BP is present in the reactive solution instead of the combination of BP and monomer. After irradiation, the film was clearly washed with acetone to remove the residual photoinitiator and then dried to constant weight at room temperature.…”

“…These results were just similar to those in the one-step method. 19 Since BVE is a typical monomer for cationic polymerization, as commonly known, it is impossible to undergo radical homopolymerization. Due to the great steric hindrance, MAH is difficult to perform homopolymerization under usual conditions and only some short graft chains could be obtained.…”

“…This result is just similar to that in the one-step photografting polymerization. 19 2) Acetone has better solubility for the component of the graft chains (MAH-alt-BVE) than acetic anhydride, so the graft chains can be thoroughly swelled in the presence of acetone (or other similar solvent, e.g., THF), resulting in the increasing mobility of the graft chain radicals. As a result of these two factors, the graft polymerization could be greatly promoted in the co-solvent medium, and consequently high grafting yield was obtained within short reaction time.…”

“…In our previous work, 19 MAH/BVE had been facilely photografted onto PP film via one-step method, and the property (e.g., hydrophilicity) of the film surface was effectively improved. In that method, the reactive solution composed of monomer and photoinitiator was coated on the film surface first, then put under UV radiation to perform graft polymerization.…”

Two‐stage grafting onto polyethylene fiber by radiation‐induced graft polymerization and atom transfer radical polymerization

“…ATRP initiators have been introduced onto the surfaces of the polyolefin substrates by ultraviolet irradiation and block copolymer chains grafted onto the substrates. [18][19][20][21] However, the structures of the monomers for this method are limited, and it is particularly difficult to graft water-soluble monomers, because the surface of the polyolefin substrate is hydrophobic.…”