For example, having an odd or even number of methylene units between the thiol head group and a biphenyl-containing tail affects the SAM stability and dose necessary for cross-linking. It was also shown that the structure and packing density of aromatic SAMs may affect the stability and electron dose required for cross-linking. 23 This was shown to be in contrast to the behavior exhibited by electron-irradiated aliphatic SAMs. However, the electron-irradiated region was shown to be more resistant to chemical etching than a BPT SAM that was not exposed to electrons and was more thermally stable with respect to C and S desorption. An electron dose of 10,000 μC/cm 2 led to loss of FTIR features indicative of aromaticity. The idealized process is depicted in Fig. 5. XPS and near-edge X-ray absorption fine spectroscopy (NEXAFS) showed retention of conjugation for an electron dose of 3000 μC/cm 2, and FTIR suggested formation of cross-links between nearby biphenyls by electron-stimulated cleavage of C H bonds. 22 studied the interaction of SAMs of 1,1’-biphenyl-4-thiol (BPT) with 50 eV electrons. As an example, 50 eV electron beam irradiation of 4’-nitro-1,1’-biphenyl-4-thiol SAMs leads to conversion of the nitro groups to amino groups and cross-linking. Įlectron irradiation of aromatic thiol SAMs has been investigated by a number of authors. Textile surface treatment using electron beam has many advantages such as reducing VOC emissions during drying, allowing the use of solvent-free formulations, saving energy by taking place at room temperature, and increasing efficiency by shortening processing time, compared to conventional thermal curing.
Electron beams can cause free radical–initiated polymerization reactions that can then be used for coating, lamination, and graft copolymerization on textiles precoated with monomers or polymers. The use of electron beam radiation to modify the surfaces of polymer materials such as fibers, textiles, and films is becoming increasingly dominant. Reactions of organic and inorganic compounds and ions with HO radicals, hydrated electrons, and hydrogen atoms can transform persistent organics into biodegradable organics, degrade toxic compounds to nontoxic species, or degrade into complex organic compounds.
The key to applying radiation techniques for water and wastewater treatment, or the decomposition of pollutants into chemical forms, is the formation of radicals by water radiolysis or other radiation processes. Elif Şahin, in Green Chemistry for Sustainable Textiles, 2021 6.2.10 Electron beam radiationĮlectron beam radiation has been applied to the textile treatment of textile wastewater by chemical oxidation process.