Modification of Polymer Surfaces by Photoinduced Graft Copolymerization

Abstract

During the last few years, new developments in polymer photochemistry have made it possible to graft various functional monomers onto surfaces of inert polymers like polyethylene, polypropy lene and polyethyleneterephthalate. In the first attempts, initiator and monomer were transferred in vapor phase into a "UV Cure" irradiator con taining the polymer sheet to be surface grafted. After a few minutes irradiation with a high pressure mercury lamp at about 50°C, a rather complete cover of grafted acrylic acid, acrylamide and other vinyl monomers could be obtained. In later experiments a continuous grafting method has been developed where a tape or a fiber bundle after suitable pretreatment is grafted by UV irra diation for a few seconds. Homopolymer formed is removed by washing and grafted polymer analyzed by dye absorption, IR reflection and ESCA spectro scopy.During the last 30 years radiation chemistry has been and still is an active area of polymer research. High energy radiation, e.g. electron beam and gamma radiation, initiates ionization and radical formation in polymers which may result in modification, crosslinking and/or degradation. An early studied and common modification involves ionizing irradiation followed by free radical initiated graft copoly merization of monomers present or subsequently added (1). Radiation induced free radical graft copolymerization has also been accomp lished using UV light (2). Since the pioneering work by Oster et al. in the 1950 ? s (3,4;) where monomers were photografted with UV light onto polymers blended with photoinitiators, only few researchers have more recently followed up this work. The interest has been focused on the use of high energy radiation. In a study in the 1960 T s by Howard et al. (_5) thin polymer films were saturated with monomers and then modified by irradiation with

Poly(acrylic acid) surface grafted polypropylene films: Near surface and bulk mechanical response

“…Surface grafting techniques including photo-initiated grafting [10][11][12][13][14], living radical grafting [15], ceric ion induced grafting [16], layer-by-layer ionic grafting [17] and plasma polymerization [18,19] have proven to be effective to graft poly-functional monomers or polymers onto PP surfaces. Among the methods to modify polymers, radical photo-grafting polymerisation appears as an attractive method to impart a variety of functional groups to a polymer [20,21]. The advantages of photografting over other available methods are: i) easy and controllable introduction of chains, ii) high density and exact localization of chains onto the surface, iii) covalent attachment of chains which avoids delamination and assures long-term chemical stability of introduced chains, in contrast to physically attached layers [1].…”

Surface modification of silica nanoparticles by UV-induced graft polymerization of methyl methacrylate

“…Also, there is the formation of ungrafted polymer, i.e., homopolymerization of the monomer. To overcome these problems, we employed surface grafting reaction initiated by ultraviolet irradiation [11]. These reactions are of special interest because they are efficient and fast.…”

Multilayered Assembly of Cellulose Derivatives as Primer for Surface Modification by Polymerization

“…[22][23][24][25][26] They performed photografting on polyolefin films in a small reactor [24] or a Pyrex glass tube [22,23] at 60 8C. Sensitizers were coated in advance by dipping the films in acetone solution containing known quantities of sensitizer and dried to prepare sensitizer-coated films or the film was placed in a reactor together with a separate container of monomer/sensitizer solution.…”