Abstract
The hygroscopic expansion and the water sorption of a series of composite resins consisting of several binary copolymers were investigated. The hygroscopic expansion was about one third of the water sorption of each composite resin.In the composite resins containing a binary copolymer system, linear regression analysis was applied to both the hygroscopic expansion and the water sorption against the mol fraction of the components. The water sorption of each component was as follows; 2.36±0.23wt% for UDMA, 0.16±0.05wt% for bis MPEPP, 3.52±0.55wt% for TEGDMA, 2.48±0.45wt% for bis GMA. The hygroscopic expansion measurement of the composites was less affected by the elution from the composites than the water sorption measurement, thus the hygroscopic expansion measurement was suitable for the estimating the water sorption of the composite.
