Synthesis of the fluorene spiroorthocarbonate and the evaluation of its antishrinking activity in the cationic photopolymerization of an epoxy resin

In this work, the spiroorthocarbonate FSOC derived from fluorene was prepared. After characterization by FTIR and NMR spectroscopy, the synthesized FSOC was evaluated as antishrinkage additive in the cationic photopolymerization of bisglycidil ether of Bisphenol-A (DGEBA). The FSOC was mixed at 2.5-10 mol% with DGEBA. It was found that shrinkage decreased with increased concentration of FSOC. At 10 mol% of FSOC not only shrinkage was eliminated, but a small level of volume expansion was also achieved. The presence of FSOC did not interfere with the photopolymerization of DGEBA.