Polypropylene photografting

Deep-groove fibers, polypropylene, photografting, dynamic contact angle, wicking... 

UV light in a second step. In later work reported by Tazuke, Kimura et al. (6-8) successful photograftings on the polymer surface of thin films (polyethylene, polypropylene and polystyrene) were achieved with various monomers. In this work, grafting was induced by UV irradiation through the film which was in contact with a solution containing initiator and monomer. The method is slow and - in addition to surface grafting - large amounts of homopolymer are formed. 

In our surface photografting research we have developed two new processes applied to sheets, films and fibers of polyethylene (PE), polypropylene (PP) and poly(ethylene-terephthalate) (PET). 

Similar synergistic effects are found with TMPTA and the inorganic additive, lithium nitrate, for photografting to polypropylene (Table VIII). 

Table 2 Durability Test of Grafted Polymer Surface. Sample Polypropylene Film Photografted with Acrylamide(16)...

Choice of sensitizer is related to the base polymer properties. Besides triplet sensitizers, dyes(4, 5), metal salts(11, 12), and radical initiators(7, 11, 12) have been used in photografting. These sensitizers other than triplet sensitizers are, however, not capable of initiating surface photografting onto polyolefins. Although benzoin isopropyl ether has been used for photografting of polypropylene, the reaction conditions seem to be in favor of deep grafting(12). 

Piletsky SA, Matuschewski H, Schedler U, Wilpert A, Piletska EV, Thiele TA, Ulbricht M. Surface functionalization of porous polypropylene membranes with molecularly imprinted polymers by photograft copolymerization in water. Macromolecules 2000 33 3092-3098. 

Studies on photografting appear to have declined in interest. The presence of acid has been found to enhance the photografting of styrene onto polypropylene and cellulose with dimylbenzene giving good synergism. Both methyl methacrylate and methacrylic acid... 

Photochemical grafting of monomers/molecules onto substrates continues to show interest in terms of improving property requirements. Dyes have been effectively photografted onto polypropylene and nylon 6 films using 1,2-diphenyl-2,2-dimethoxyethanone while methacrylic acid and acrylamide have been successfully photografted onto polypropylene sheets using benzophenone as a sensitiser in order to modify the surface of the polymer from a hydrophobic to a hydrophilic one. A styrene-2,2,6,6-tetramethyl-4-piperidinyl... 

Table I. Photografting of Styrene In Methanol ty> Polypropylene In presence of Trlfunctlonal Monomers...

Table III. Synergistic Effect of Difunctlonal and Monofunctlonal Monomers with Lithium Nitrate In Photografting Styrene to Polypropylene...

Another report on the sequential photografting method deals with the grafting of poly(acrylic acid) on polypropylene membranes [16]. A linear relationship between irradiation time and average... 

J. Balart, V. Fombuena, J.M. Espana, L. Sanehez-Nacher, R. Balatt, Improvement of adhesion properties of polypropylene substrates by methyl methacrylate UV photografting surface treatment. Mater. Des. 33, 1-10 (2012)... 

PWO 88] Dworjanyn P.A., Garnett J.L., Synergistie effects of urea with polyfunctional acrylates for enhancing the photografting of styrene to polypropylene . Journal of Polymer Science Part C Polymer Letter, vol. 26, pp. 135-138, 1988. 

N-vinylpyrrolidone (NVP), has been seldom used in surface photografting. Recently, Chang-Min eLal have functionalized polypropylene film with NVP by UV-induced photogi ing process [6]. Polyvinypyrrohdone (PVP) is a synthetic, water-soluble polymer whieh meets a variety of applications depending on its molecular weight. PVP has the property of forming eomplexes with a wide variety of substanees such as pharmaceutical molecules, iodine, metal ions etc, [7]. PLA-PVP complexes and biod radabihty are under study. 

WETTABILITY OF PHOTOGRAFTED DEEP-GROOVE POLYPROPYLENE FIBERS... 

This paper presents photografting as a surface modification method to provide permanent wettability improvement to deep-groove polypropylene (PP) fibers. We also describe approaches to evaluate the wettability of these fibers and the wicking performance of fiber bundles when polyacrylamide (PAAm) was grafted onto the fibers. In this study, the concentration of the monomer and the UV-exposure time were altered to examine the effects of those variables on fiber hydrophilicity. Results showed lower water contact angle and improved wicking capacity upon modification with PAAm. 

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