Grafting of Linear Low Density Polyethylene (LLDPE) onto Tallow via Anhydride: Effect of Residence Time

Abstract

Grafting polymerization by reactive small molecules involves the formation of graft copolymers from a reaction between polymers and monomers. Monomer units can be propagated onto the polymer backbone to form a graft structure. In the polymer processing industry, the internal mixer is the most important piece of machinery. The study used the internal mixer as a reactor to make a reactive process with the interest in residence time,as the residence time is importance in the chemical reaction. By increase the residence time, the optimum degree of grafting may be occurred. The objectives of this study are to increase the knowledge and understanding of the internal mixer process, determine optimum residence time process variables for grafting LLDPE and study the effect of the residence time toward the LLDPE grafting process. Several residence times was choosing for the specified sample, to study the effect of the residence time which were 60 s, 120 s, 180 s, 240 s, 300 s and 600 s. Degree of grafting (DOG) was calculated to determine the grafting of LLDPE grafted copolymers and a series of samples in which degrees of grafting had been determined by chemical titration. Residence time at 300 s produces the optimum DOG of monomer onto polymer. Longer residence time will produce high degree of grafting but will cause other issues such as increasing in gel content and lower the mechanical properties of the grafted polymer.