MgO-Lignin Dual Phase Filler as an Effective Modifier of Polyethylene Film Properties

Functional magnesium oxide-lignin hybrid materials were obtained via mechanicalgrinding. Their particle shape and size as well as physicochemical properties were characterized.MgO-lignin materials with biocomponent content (between 20% and 80% amount of total weight offiller) were used as a partially bio-structured modifier of low density polyethylene. The compositeswith 5% by weight of dual fillers and polyethylene grafted with maleic anhydride werecompounded in a twin screw extruder working in co-rotating mode. The prepared blends were castextruded using a single screw extruder and laboratory cast line. The properties of the obtainedfilms were verified in case of their weldability. The seal strength as well as shear test and tearstrength of the welded sheets were examined. The results showed that the shortest equivalent timerequired to perform correct weld occurred in the system, where the highest amount of lignin wasused in hybrid filler MgO-L (1:5 w/w). From mechanical tests of welds, a sharp increase in ultimateseal force was noticed for almost all compositions with lignin, especially where MgO was coupledwith a high lignin content. For those composition seal open force raised up to 37.0 N, from thevalue of 23.6 N, achieved for neat low density polyethylene (LDPE). Tear strength of weld sheetsconfirmed once more that LDPE composition with MgO-L (1:5 w/w) achieved the highest ultimateforce with its value of 71.5 N, and it was ~20.0 N higher than in the case of neat LDPE.