Strategies for maximizing free‐radical grafting reaction yields

摘要: It is very challenging to obtain large amounts of vinyl monomers grafted onto polymer backbones in the melt through a free-radical mechanism. The objective this study was develop strategies that would allow one maximize amount 3-isopropenyl-α,α-dimethylbenzene isocyanate (TMI) polypropylene (PP) by reactive extrusion processes. For purpose, an internal batch mixer used simulate potential Two were studied: first apply comonomer concept developed previous studies. More specifically, styrene (St) as control grafting yield and molar mass TMI-grafted PP. second strategy delt with feeding mode reactants. modes investigated: (a) one-pot feeding, is, total TMI, St, peroxide premixed PP whole mixture then charged reactor at once; (b) stepwise divided several equal fractions. fraction reactor. After certain reaction time, other fractions after another time intervals. Both shown be good maximizing yields. They can easily adopted if carried out screw extruder. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1799–1807,