Novel Tetraspiroorthocarbonates as Successful Anti-shrinking Agents for the Photopolymerization of Epoxy Monomers |
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Authors: | Ricardo Acosta Ortiz María Lydia Berlanga Duarte Amy Grace Savage Gómez Marco Sangermano Aida E García Valdez Marissa Perez Ramírez |
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Institution: | 1. Centro de Investigación en Química Aplicada , , Blvd. Enrique Reyna, Saltillo , Coahuila , México;2. Politecnico di Torino , , Cso. Duca degli Abruzzi, Torino , Italia |
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Abstract: | A pair of novel tetrafunctional spiroorthocarbonates (TETRASOC) was prepared in three stages. First, glycerol was reacted with tetraethyl orthocarbonate to form a pair of isomeric hemi spiroorthocarbonates (HEMI SOC-OLs) by monocyclization of glycerol. Formation of these two isomers depends on terminal or adjacent hydroxyl groups of glycerol reacting with the tetraethylorthocarbonate to form five and six-membered ring HEMI SOC-OLs. Second, the HEMI SOC-OLs were made to undergo another cyclization reaction by reacting with 1,3-propanediol, to form a pair of spiroorthocarbonates with one hydroxyl group (SOC-OL). In the third stage, the SOC-OL was used as nucleophylic reactant to displace the bromine atom of pentaerythritol bromide to form the final product TETRASOC. A volume change study was carried out to determine the efficiency of TETRASOC as an anti-shrinking additive finding that even at a low concentration of 7 mol%, it caused a 2.18% expansion of the polymeric volume of a bis epoxycyclohexane monomer (3,4-EP). Dynamic Mechanical Analysis (DMA) determined that the flexibilization induced by the TETRASOC in the polyether derived from 3,4-EP did not adversely impact the mechanical properties of the polymer. |
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Keywords: | Spiroorthocarbonates cationic photopolymerization shrinkage |
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