Please solve and give a well explained answers

A model polyethylene is prepared by hydrogenating a narrow distribution $1,4-$

polybutadiene by anionic polymerization. If the polymerization yields $8\%$ "vinyl" or $1,2-$

addition, what would you estimate for the equilibrium melting point of the resulting

polyethylene. Use $H_f=8220Jmo{l}^{-1}.($HINT: it might be helpful to think of this as a

random copolymer and consider the $1,2-$additions as defects$)$