GRAFTING OF METHYL VINYL KETONE AND ACRYLONITRILE ONTO MIXED HARDWOOD PULP:EFFECTS ON THE PHYSICAL PROPERTIES OF GRAFTED PULP

摘要

The effects of grafting on both unbleached and bleached mixed hardwood pulps with hydrophilic methyl vinyl ketone and hydrophobic acrylonitrile were studied in an aqueous medium,with potassium persulphate as initiator,under the catalytic influence of FeCl3.Both percent grafting and grafting efficiency depend on the concentrations of monomer,initiator,catalyst,reaction time and temperature.Under optimised condition,the percent grafting and grafting efficiency were of 13.5% and 16.9% in unbleached and of 8.5% and 10.8%,respectively,in bleached pulps,for methyl vinyl ketone,and of 12.2% and 15.3% in unbleached and of 10.8% and 13.5%,respectively,in bleached pulps,for acrylonitrile.Methyl vinyl ketone manifests a hydrophilic character in the grafted pulp,which increases the dry strength of paper produced from it.Acrylonitrile grafted pulps with hydrophobic character produced inferior pulp sheet than the non-grafted pulp.Between unbleached and bleached grafted pulps,the former ones showed better physical properties.Brightness of both pulps was reduced by grafting.