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.
Acknowledgments
The authors would like to thank the Mexican National Council of Science and Technology (CONACYT) for funding this project (80108). Assistance in running NMR, DSC and DMA samples by Judith Cabello, Sandra Ramos, Guadalupe Mendez and Silvia Torres is gratefully acknowledged.