Modification of a Bitumen with Various Polymers for Use in Built-Up Roofing Membranes

This paper summarizes the experimental results in a new class of polyolefm co- and terpolymers containing "reactive" p-methylstyrene ( p-MS) groups, which includes the materials from high Tm thermoplastics to low Tg elastomers. Due to the extraordinary copolymerization capability of metallocene catalysts with constrained ligand geometry, p-MS can be effectively copolymerized with (alpha)-olefins (i.e., ethylene, propylene, l-octene, etc.) to form co- and terpolymers having narrow molecular weight and composition distributions. Comparing with other relative styrenic comonomers, i.e., styrene, o-methylstyrene and m-methylstyrene, p-MS shows significantly higher reactivity in metallocene catalysis. In turn, the incorporated p-MS units in polyolefins are very versatile, which not only can be interconverted to various functional groups, such as -OH, -COOH, anhydride, silane and halides, but also can be conveniently transformed to "stable" anionic initiators for "living" anionic graft-from polymerization reactions. Many new functional polyolefin graft copolymers have been prepared, containing polyolefin backbone (PE, EP, EO, etc.) and functional polymer side chains, such as PMMA, PAN, PS, etc.