Aliphatic polycarbonate resins for radiation curable powder coatings

Thermosetting resins based on semi-crystalline poly(dimethyl trimethylene carbonate) (PDTC) were synthesised and characterised. Polymers with linear and branched architectures were synthesised through cationic ring opening polymerisation (CROP) of dimethyl trimethylene carbonate (DTC) using a series of polyols as initiators and fumaric acid as catalyst. The best powders were stable during storage at 45 °C for one week and could subsequently form films at temperatures between 100 and 115 °C. Functionalisation of the resins with methacrylic anhydride enabled curing by UV-initiated radical polymerisation. Rheology measurements showed that the architecture had a significant effect on the melt viscosity, which shows that the rheological properties can be tuned for use as low temperature curing powder coatings.