New Polyisobutylene-based Uv-curable Flexible Coatings
New UV-curable solventless flexible transparent coatings have been prepared of acrylate- and methacrylate-capped linear or three-arm star polyisobutylenes PIB in the presence of conventional “reactive diluents” (multifunctional acrylate or methacrylate esters) and a UV-sensitizer. Solvent extraction studies show essentially complete network formation. The swelling ratios were surprisingly small indicating highly crosslinked gels. Films cast on glass, Teflon, stainless steel and aluminum and UV cured very strongly adhere to these surfaces and could not be removed without destroying the films. Films obtained by casting on aluminum, UV curing and subsequently dissolving the support by concentrated NaOH, contain no pinholes. DSC traces show a low and a high temperature transition characteristic of a domain separated morphology of soft PIB and hard acrylate or methacrylate segments. The exact positions of the transitions in the range from −57 to −45°C, and from 62 to 78°C are affected by the overall film composition. Tensile and elongation data have been obtained. The water absorption of these highly hydrophobic coatings is negligible.
Puskas, Judit; Kaszas, Gabor; Chen, C. Charles; and Kennedy, Joseph P., "New Polyisobutylene-based Uv-curable Flexible Coatings" (1988). Chemical and Biomolecular Engineering Faculty Research. 544.