In recent years, a number of heterogeneous methods'-'* have been developed for oxidizing lowdenaity polyethylene (LDPE) and also the polyol& in general. However, these entail mixing problems and result in inhomogeneous oxidation. A homogeneous method, on the other hand, can achieve controlled, uniform, and optimal bulk and surface oridation. The phase W e r catalyste have of late opened the avenue8 for oxidation at specific sites for a wide variety of organic m0lecule4'~-'~ but they have never been applied for polymer modification in homogeneous and biphasic systemg We have developed a new methd for oxidation of polyoleiins which is homogeneous in nature and utilizes a phase t d e r catalyst to transfer the oxidant into the hydrocarbon phase. The present communication describes the preliminary investigation regarding the utility of the "purple hydrocarbon" reagent as an effective homogeneous oxidizing agent for LDPE.
Mat8riala
Polyethylene samples were supplied by 1.E.L (Chemicals Division). They contained no commercial additives. All other chemicals like potassium permanganate, sodium chloride, and tetrabutyl ammonium bromide were of analytical grade. The solvents, benzene and toluene, were of spectroecopic quality.
PREPARATION OF PURPLE BENZENE
Potassium permanganate (5 g) was dissolved in 30 mL of 10% sodium chloride solution (w/w) and a bright colored solution was obtained. To this, 30 mL of benzene was added. This mixture was vigorously stirred and allowed to stand for a brief period. It waa noted that the purple color remained entirely in the aqueous layer. To this, an aqueous solution of tetrabutylammonium bromide (prepared by dissolving 4 g salt in 5 mL of-water) was added, and the mixture was vigorously stirred and allowed to stand. The nonaqueous phase which formed the upper layer turned purple. This mixture was called "purple benzene" and used as the oxidizing agent. In a s i m i h . manner " purple toluene" was also prepared.