suppose i take 5 gm of polymer A and graft using 5 gm of polymer B
The resultant grafted product would weigh much more than 10 gms Grafting will be done via free radical polymn
Dear Sailaja Rrn, providing the grafting efficiency is 100% (something unrealistic) and there is (are) no byproduct loss, the only additional mass is that of the part of the radical initiator which will be attached to one side of the grafts (generally negligeable). If you have an additional mass to that of the sum of the masses of both components of the graft, may be this is due to a residual solvent. My Regards
If you are using GPC to determine the molecular weight, you need to consider that the change in morphology and chemistry can affect the response of the instrument. Grafted copolymer may fold differently and have different refractive index compared to the starting polymers, for example.
Theoretically, the new molecular weight should be the sum of the starting MWs, keeping the reaction progress into account.
Molecular wt of the polymer will be dependent upon the stoichometric quantities of the monomers and initiator conc. Since reaction won't take place 100% there would be unreacted material in the reaction mixture. In spite of all these things the mass of ultimate polymer which observe to be higher may be by a wafer thin margin which is attributed to consistency of reactants, initiator, solvent, and most importantly grafted polymer. You need to calculate the mass correctly using, appropriate volume, density.
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