Abstract
A series of stoichiometric hydrophilic epoxy networks was prepared by reaction of a,x-diamino
terminated polyoxypropylene of average molar mass 430, 2000 and 4000 g/mol
with polyoxyethylene bis(glycidyl ether) of average molar mass 526 g/mol. The networks
were investigated by dynamic mechanical analysis (DMA) and differential scanning calorimetry
(DSC). Single glass transitions observed in the networks strongly suggest that
the networks present homogeneous single phase, i.e., polyoxypropylene (POP) and polyoxyethylene
(POE) are homogeneously built in the network structure. The homogeneity
of the networks is also confirmed by absence of a crystallization of POE. Hydrogels obtained
by swelling of the networks in water exhibit a strong dependence of swelling degree on
temperature. The temperature sensitivity of the hydrogels increases with growing molar
mass of the POP used in the network preparation. The swelling behavior of the hydrogel
containing POP of highest molar mass (4000 g/mol) is close to a discontinuity expected
at a temperature ca 1011 ºC.
