Synthetic polymers surface modification

T. Bahners, T. Textor and E. Schollmeyer, Photon-based processes for the surface modification of synthetic fibers, in Polymer Surface Modification Relevance to Adhesion, Vol. 3, K. L. Mittcd (Ed.), pp. 97-124, CRC Press, Boca Raton, FL (2004). 

Ortiz-Magan A.B., Pastor-Bias M.M., Eerrandiz-Gomez T.P., Morant-Zacares C., and Martfn-Martfnez J.M., 2001, Surface modifications produced by N2 and O2 RF-plasma treatment on a synthetic vulcanised rubber. Plasmas Polym., 6(1,2), 81-105. 

Amylose brushes (a layer consisting of polymer chains dangling in a solvent with one end attached to a surface is frequently referred to as a polymer brush) on spherical and planar surfaces can have several advantageous uses, such as detoxification of surfaces etc. The modification of surfaces with thin polymer films is widely used to tailor surface properties such as wettability, biocompatibility, corrosion resistance, and friction [142-144]. The advantage of polymer brushes over other surface modification methods like self-assembled monolayers is their mechanical and chemical robustness, coupled with a high degree of synthetic flexibility towards the introduction of a variety of functional groups. 

Abramovitch et al. " and Banks et al. discovered that unlike most aryMtrenes, polyfluorinated arylnitrenes have a bountiful bimolecular chemistry. Perfluorophen-ylnitrene reacts with diethylamine to form a hydrazine, with tetramethylethylene to form an aziridine and forms robust adducts with benzene and even cyclohexane. Polyfluorinated arylnitrenes are useful reagents in synthetic organic chemistry, photoaffinity labeling, and for the covalent modification of polymer surfaces. ... 

If the polymer surface to be modified possesses reactive groups capable of combining other components, such as water-soluble polymer molecules, surface modification can be readily conducted by chemical coupling reaction. Numerous synthetic reactions are available for this purpose. Bergbreiter [2] reviewed various... 

In many experiments, it appears that such drastic solvent extraction can remove the major part of the synthetic polymer, showing that the grafted polymer presents, in point of fact, a good "adhesive" bondability. However, in the case of surface modification, a heavy grafting is not necessary and the degre of permanence is a function of the insolubility of the homopolymer in the solvents used in the common course of subsequent treatments. So it can be inferred that this notion of grafting may be dependent on the efficiency of the solvent extraction. 

Increasing applications of oxidoreductases for modifying surface properties of synthetic polymers have been reported. A good example is surface modification... 

Challenges for Enzymatic Surface Modification of Synthetic Polymers... 

Synthetic polymers are also a major contributor in the textile industry. Synthetic fibers show excellent strength properties, chemical resistance, wrinkle resistance, and abrasion resistance. These fibers also show some undesired properties such as hydrophobicity due to which they show wearing discomfort as perspiration cannot penetrate the fabric and lower the reactivity with chemical agents, which normally act as barrier to other finishing agents. These problems are due to the presence of hydrophobic groups on the surface of synthetic polymers. Therefore, surface modification of synthetic polymers is very necessary. 

The surface of the synthetic polymers can be modified by chemical, physical, and enzymatic methods (Figure 4.1). Chemical modification requires harsh reaction due to which strength properties of polymers get affected. Zeronian and Collins (1989) reported a 10-30% weight loss in polyester fibers after chemical treatment. Additionally, chemical treatments are difficult to control and have negative impacts on the enviromnent. 

Physical methods include plasma treatments, UV irradiation, corona discharge, and flame treatment. Among these, plasma treatment is widely used for the surface modification of synthetic polymers. Plasma can be obtained by exciting gases into an energetic state by radio frequency, microwave, or electrons from a hot filament discharge. Generation of plasma requires a vacuum, which normally poses several... 

FIGURE 4.1 Methods of surface modification of synthetic polymers. 

Very few reports are available for the enzymatic surface modification of synthetic fibers. Peroxidase, lipase, cutinase, nitrilase, nitrile hydratase, amidase, protease, and hydrolase have been reported for the surface modification of synthetic polymers (Table 4.1). 

Peroxidases belong to the class of oxidoreductases containing iron (111) and protoporphyrin IX as the prosthetic groups. Peroxidases catalyze the reduction of peroxides and the oxidation of many organic and inorganic compounds. These enzymes are widely used for the removal of phenolic compounds, decolorization of synthetic dyes, deodorization of swine manure, in enzyme immunoassays, for biofuel production and organic and polymer synthesis (Hamid and Rehman, 2009). Peroxidases have also been used for the surface modification of poly-p-phenylene-2,6-benzo-bisthiazole (PBO), polyethylene, and grafting of acrylamide onto kevlar fibers. 

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