Preparation and characterization of porous polymer membrane from kappa-iota carrageenan blend

Carrageenan is a well-known hydrophilic biopolymer with the ability to form gels for various
extensive applications such as biomedicine and the food industry. The purpose of this study was to prepare
a porous membrane from kappa (K-CAR) and iota (I-CAR) carrageenan blend by freeze-drying to maintain
the porosity based on the effect of I-CAR ratios. The swelling behavior increased (from 1221 to 1816%)
with adding I-CAR in ratios of K:I CAR from 1:0 to 1:1 due to increasing electrostatic repulsion between
the ester sulfate groups on the carrageenan chain. Scanning electron microscopy was used to study the pore
formation of the porous membrane, which showed that the micropore structure and pore size increased
with increasing I-CAR. Furthermore, dynamic mechanical data for tension and compression revealed
that incorporating I-CAR into K-CAR reduced the storage modulus for tension from 2.08 to 0.38 MPa and
for compression from 0.59 to 0.07 MPa.