UV curing and matting of acrylate nanocomposite coatings by 172 nm excimer irradiation
2008; Elsevier BV; Volume: 64; Issue: 4 Linguagem: Inglês
10.1016/j.porgcoat.2008.08.009
ISSN1873-331X
AutoresFrank Bauer, Ulrich Decker, Konstanze Czihal, R. Mehnert, Carsten Riedel, Marion Riemschneider, Rolf Schubert, Michael R. Buchmeiser,
Tópico(s)Silicone and Siloxane Chemistry
ResumoFor UV-curable acrylate coatings reinforced by silica nanoparticles, the effect of 172 nm excimer irradiation on the surface roughness has been studied. A dual UV lamp set-up consisting of a 172 nm excimer lamp and a mercury arc lamp allowed obtaining gloss levels down to 0.5 units (at 60°) depending on the acrylate formulation and curing conditions. Moreover, UV matt-finished sample showed enhanced surface hardness and increased chemical resistance. It is assumed that 172 nm excimer irradiation resulted in a higher network density via additional cross-linking reactions. To study the depth profile of acrylate conversion for coatings cured by the combination of a 172 nm excimer lamp (accountable for surface curing) and a mercury arc lamp (responsible for through curing), FTIR microscopy as well as (Ge)ATR-FTIR having an IR penetration depth of less than 0.5 μm have been applied. Providing the presence of a photoinitiator as well as the absence of oxygen inhibition, similar degrees of double bond conversion of about 90% were observed on the entire area of the cross-section of the coating, i.e. the wavelength of UV irradiation was found to have no significant impact on acrylate conversion.
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