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An analysis of photopolymerization kinetics and stress development in multifunctional acrylate coatings
Author(s) -
Stolov Andrei A.,
Xie Tao,
Penelle Jacques,
Hsu Shaw L.,
Stidham Howard D.
Publication year - 2001
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.10731
Subject(s) - materials science , cantilever , polymerization , composite material , monomer , deflection (physics) , kinetics , acrylate , photoinitiator , stress (linguistics) , anisotropy , photopolymer , polymer , optics , philosophy , linguistics , physics , quantum mechanics
Polymerization kinetics and stress buildup of multifunctional acrylic coatings have been studied simultaneously using a cantilever deflection method and real time one‐bounce infrared reflectance spectroscopy. Cantilever deflection due to stress buildup in the film is correlated with crosslink density in the polymerizing mass. Stress buildup was observed not to occur instantaneously after radiation was introduced but rather after a certain time interval. The time delay between onset of polymerization and initiation of stress indication is attributed to the introduction of crosslinks, leading to a gel state. The measured stress‐conversion relationship can be predicted using an approach incorporating monomer reaction probability. Stress buildup can vary considerably as a function of processing conditions such as film thickness, temperature at solidification point, and the type, concentration and absorptivity of photoinitiator, which govern the degree of crosslinking. Under certain processing conditions, an uneven distribution of the monomer conversion in the film may severely alter the stress‐film thickness relationship. In some cases the cantilever material anisotropy can be detected based on the cantilever deflection measured.