Olefin-diolefin copolymers

Lubricants Olefin-diolefin copolymers United States 3,231,498 1966 Chevron Research ... 

Well developed is the anionic polymerization for the preparation of olefin/ diolefin - block copolymers using the techniques of living polymerization (see Sect. 3.2.1.2). One route makes use of the different reactivities of the two monomers in anionic polymerization with butyllithium as initiator. Thus, when butyllithium is added to a mixture of butadiene and styrene, the butadiene is first polymerized almost completely. After its consumption stryrene adds on to the living chain ends, which can be recognized by a color change from almost colorless to yellow to brown (depending on the initiator concentration). Thus, after the styrene has been used up and the chains are finally terminated, one obtains a two-block copolymer of butadiene and styrene ... 

J. Furukawa, Alternating copolymers of diolefins and olefinic compounds. Prog. Polym. Sci. Japan 5, 1 (1973). 

Cross-linked PVP is applied as a semipermeable membrane [492]. Furthermore, PVP can be used for the encapsulation of hydrophobic material [492]. Poly(iV-vinylpyrrolidone-co-styrene) was found to be an extraordinary catalyst in two-phase reactions [532]. For special applications one can design copolymers of NVP with different olefins and diolefins, or it is possible to graft NVP onto cellulose, polyolefins, keratin, collagen, and others, or to graft PVP with olefins [492,533-542]. 

Modifications to the Ziegler-Natta catalyst system have led to the preparation of alternating copolymers from olefins, such as ethylene and propylene, and diolefins, such as butadiene and isoprene. In typical systems (Furukawa 1972, 1974a, b) the catalyst is prepared at very low temperatures (-70°C or below) from three components a... 

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