Polypropylene surface grafting

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, polypropylene and polyethyleneterephthalate. In the first attempts, initiator and monomer were transferred in vapor phase into a "UV Cure" irradiator containing the polymer sheet to be surface grafted. 

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. 

Figure 3. Reflection infrared spectra (ATR-IR) of a polypropylene-j surface before (A) and after (B) grafting with acrylamide (AM) by the vapor phase process (above). ESCA spectra of the same surface before (dotted lines) and after (full lines) the surface grafting (below).

Grafting of Acrylic Acid Derivatives onto Polyethylene and Polypropylene Surfaces... 

Figure 4. Kinetics of surface grafting of polyethylene (PE) and polypropylene (PP) films with acrylamide (AM) by the vapor phase method measured as light absorption at 600 nm after dipping in an aqueous solution of crystal violet (CV).

Figure 16. Surface grafting of polypropylene film strips after 10 sec. irradiation measured as light absorption after dipping in aqueous crystal violet solution. The presoaking solutions contain 0.2 M benzophenone (all) and 1.3 M acrylamide (1), 0.8 M (2),...

Polypropylene was grafted onto a nanotube surface using benzoyl peroxide and is discussed by Khabashesku et al. (4). 

In the mid to late 1990s, Mimotopes was producing rigid injection molded polypropylene devices that were surface grafted with either a hydrophilic copolymer of methacrylic acid/dimethyl acrylamide or the relatively hydrophobic polystyrene.12 The polymer was then suitably deriva-tized to allow the incorporation of a linker system. In contrast to the various commercial resins available at the time, the Crown was a macroscopic, quantized solid phase. As shown in Fig. 2, the Crowns were typically fitted to a polypropylene stem, which in turn could be fitted into a... 

Fig. 6 Reaction scheme of covalent alanine grafting onto polypropylene surfaces...

Huang, C.Y., Chen, C.L., 2002. The effect of plasma surface modification from a rotary plasma reactor on the styrene grafting onto a polypropylene surface. Surf. Coat. Technol. 153,... 

Macromolecular Symposia Vol.119, July 1997, p.277-82 FTIR AND ATR ANALYSES ON A POLYPROPYLENE (PP) SURFACE AFTER PLASMA TREATMENT IN THE STUDY OF CHITOSAN SURFACE GRAFTING TO IMPROVE PP DYEING BEHAVIOUR Rochery M Lam T M Crighton J S GEMTEX-ENSAIT Leeds,University... 

Singh, R. P. 1992. Surface grafting onto polypropylene—A survey of recent developments. Progress in Polymer Science 17 251-281. 

The pin consists of a radiation-grafted polypropylene crown fitted to an inert polypropylene stem . Graft polymers used with the Multipin system include polystyrene, a methacrylamide copolymer (38), and poly(hydroxyethyl methacrylate) (34) (HEMA). We have found that the HEMA surface is best suited to peptide synthesis. Historically, peptides were prepared in a non-cleavable format on the crown surface for epitope mapping applications (39). Over the past decade, however, most peptides prepared by the Multipin method have been synthesized on cleavable linkers. The linkers used for peptide synthesis are outlined below. 

Grafting can also be applied for the surface modification of the membrane. Although the method should work for any polymeric materials, most of the recent works on membrane surface graft polymerization were on polyamide thin-film composite (TFC) membranes or porous polypropylene membranes. 

Barner L (2003) Surface grafting via the reversible addition-ftagmentation chain-transfer (RAFT) process from polypropylene beads to core shell microspheres. Aust J Chem 56 1091 Bart J (2005) Additives in polymers industrial analysis and applications. Wiley, New York... 

Questions must exist in general about polymers and their graft and block copolymers. Polypropylenes grafted with polar monomers such as maleic anhydride seem to be not fully miscible with neat polypropylene. The graft copolymers are foimd to exist in higher concentrations near surfaces containing moisture. 

Alkenylsuccinic anhydrides made from several linear alpha olefins are used in paper sizing, detergents, and other uses. Sulfosuccinic acid esters serve as surface active agents. Alkyd resins (qv) are used as surface coatings. Chlorendric anhydride [115-27-5] is used as a flame resistant component (see Flame retardants). Tetrahydrophthalic acid [88-98-2] and hexahydrophthalic anhydride [85-42-7] have specialty resin appHcations. Gas barrier films made by grafting maleic anhydride to polypropylene [25085-53-4] film are used in food packaging (qv). Poly(maleic anhydride) [24937-72-2] is used as a scale preventer and corrosion inhibitor (see Corrosion and corrosion control). Maleic anhydride forms copolymers with ethylene glycol methyl vinyl ethers which are partially esterified for biomedical and pharmaceutical uses (189) (see Pharmaceuticals). 

Photodegradation of polyethylene waste can be markedly accelerated via its grafting with acrylamide [98], In contrast, photostabilization of polyethylene and polypropylene can be achieved as a result of the grafting of 2-hydroxy-4-(3-methacryloxy-2-hydroxy-propoxy) benzophenone using gamma radiation [ 147], In this case, the grafted compound acting as a U V stabilizer is chemically bound to the backbone chain of the polymer and its evaporation from the surface can be avoided. 

After this treatment the surface energy of the fibers is increased to a level much closer to the surface energy of the matrix. Thus, a better wettability and a higher interfacial adhesion are obtained. The polypropylene (PP) chain permits segmental crystallization and cohesive coupling between modified fiber and PP matrix [40]. The graft copolymerization method is effective, but complex. 

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). 

---