Structural study of a varnish by electron spin resonance

✍ Scribed by S. Cottier; A. M. Riquet; A. Feigenbaum; P. Mortreuil

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 592 KB
• Volume: 62
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19961226)62:13<2219::aid-app6>3.0.co;2-m

✦ Synopsis

Related to the study of interactions between food and aluminum cans, structural features of a vinylic organosol coating were studied by electron spin resonance (ESR). Paramagnetic probes were incorporated separately in the normal formulation of a widely used varnish, which was then cured a t high temperature for different times. The behavior of aminoxyl probes, differing by their volatility and their functional groups, was studied. When 4-amino-2,2,6,6-tetramethylpiperidinoxy (3) was used as probe, it grafted onto the polymeric chains during curing. Two transitions could then be observed, corresponding to N O in two environments, which were assigned to the PVC (Tfs, 132-142OC) and to the epoxyphenolic (EP) (T50G, 142-152°C) phases of the varnish. This was confirmed by a separate study of the PVC and EP constituents. Both transition temperatures depended on the extent of curing, suggesting that the PVC phase was plasticized by reactive constituents of the coating. The transition temperatures were also influenced by the extent of penetration of the PVC in the E P phase. Probes which could not graft on the polymer were lost by volatilization during curing.