Graft Copolymerization of Styrene on Polyethylene

Safety precautions Before this experiment is carried out, Sect. 2.2.5 must be read as well as the material safety data sheets (MSDS) for aU chemicals and products used. 

weighed polyethylene film (length 50 mm, breadth 25 mm, thickness 0.1-0.2 mm) is placed in a tube (about 70 ml capacity) fitted with a ground glass joint and stopcock. After addition of some crystals of benzophenone (as sensitizer) the sample is heated for 1 h on a water bath at 60°C. The outside of the tube is dried, the stopcock closed, and the tube exposed to 15 min irradiation from a mercury lamp (maximum of emission in the region of A, = 253-254 nm). 

The amount of grafted styrene is given by the increase in weight of the fUm. It may also be calculated quite well from the densities of polyethylene (di), polystyrene (d2), and the graft copolymer (d3) according to the following Eq. 3.31  

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