Hammer, Theodore J.; Pugh, Coleen; Soucek, Mark D. published the artcile< Ultraviolet-Curable Cycloaliphatic Polyesters Containing Spiroacetal Moieties for Application as Powder Coatings>, Category: esters-buliding-blocks, the main research area is UV curable cycloaliphatic polyester spiroacetal powder coating.
Thermosetting cycloaliphatic powder coatings that exhibit good weatherability, corrosion resistance, and mech. properties have been desired for some time. Unfortunately, most cycloaliphatic resins have glass transition temperatures (Tgs) that are too low for powder coating applications. In this study, a series of UV-curable, cycloaliphatic polyesters was synthesized from 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (spiroglycol), 1,4-cyclohexanedimethanol, and 1,4-cyclohexanedicarboxylic acid. The oligomers were characterized by 1H NMR spectroscopy, Fourier-transform IR spectroscopy, gel-permeation chromatog., and differential scanning calorimetry. The Tg value, the tensile strength, and the modulus of the crosslinked polyesters systematically increased with the spiroglycol (SPG) loading level. Dynamic mech. anal. experiments highlighted structure-property relationships and showed evidence of secondary relaxations at around -44°C. These β-relaxations were attributed to conformational transitions of the cycloaliphatic rings. The oligomers that contained 30 and 45 mol % SPG had Tgs that were suitable for powder coating applications. As such, they were formulated into UV-curable powder coatings. Coated test panels were evaluated in a salt spray chamber (ASTM B117) and a QUV weatherometer. The impact resistance, adhesion, and pencil hardness properties of the coatings were also evaluated. When compared to conventional (aromatic-based) controls, the cycloaliphatic powder coatings exhibited comparable weatherability, corrosion resistance, and Tgs along with superior impact resistance, substrate adhesion, and resistance to yellowing. These findings suggest that the cycloaliphatic powder coatings would be good alternatives to aromatic-based systems that are used in exterior durable clear coat applications.
ACS Applied Polymer Materials published new progress about Adhesion, physical. 112-63-0 belongs to class esters-buliding-blocks, and the molecular formula is C19H34O2, Category: esters-buliding-blocks.
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics