Graft polymers of eucalyptus lignosulfonate calcium with acrylic acid: Synthesis and characterization

The graft copolymerization of eucalyptus lignosulfonate calcium (HLS-Ca) from hardwood and acrylic acid (AA) was investigated by using Fenton agent as a coinitiator. The influences of reaction conditions on grafting parameters i.e. product yield ( Y %), AA conversion ( C %), grafting ratio ( G %) and grafting efficiency (GE%) were carefully studied. The effects of the phenolic hydroxyl (Ph-OH) group on the polymerization of AA and grafting reaction were researched. Graft copolymers were identified by the new absorption at 1727   cm −1 , more homogenized morphology and higher decomposition temperature after grafted with AA, as illustrated in FTIR, SEM and TG spectra. The optimum synthesis conditions are as follows: H 2 O 2   =   25.2   mol/L, FeCl 2   =   63.0   mol/L, T   =   50   °C and t   =   2   h and the optimum percentages of Y , C , G and GE are 97.61%, 95.23%, 71.29% and 78.85%, respectively. The Ph-OH group of HLS-Ca cannot inhibit the polymerization of AA and is involved in the grafting reaction as an active center.