Interpenetrating polymer network (IPN) hydrogel based on crosslinked natural rubber (NR) latex and crosslink cassava
starch (St) was successfully prepared by a solution blending technique. Crosslinked NR latex was firstly prepared in emulsion
state at 70°C by using potassium persulfate as initiator and N, N'-methylene-bis-acrylamide (MBA) as crosslinker. Secondly, the
crosslinked NR latex was mixed then with gelatinized cassava starch and maleic acid (MA) as crosslinker for starch at ambient
temperature by using mechanical stirrer. Finally, the mixture was casted on a glass mould to form IPN NR/St sheet via
crosslinked reaction at 120 o
C in oven for 1.5 h. The water absorption, tensile properties, gel and soluble fraction in water as well
as biodegradation of IPN NR/St hydrogels were investigated. It was found that water absorption, soluble fraction, biodegradation
and tensile properties decreased with increasing NR contents, while gel fraction in water and elongation at break increased. This
was because the rubber molecules prevented the hydrogel from dissolution in water and degraded by microorganism.
Furthermore, by immersion of IPN NR/St for long time, water absorption of hydrogel increased with increasing rubber contents
due to the effect of elasticity of rubber molecule to easy expansion of INP NR/St hydrogel.