Olefins, block copolymers

Chain Shuttling Catalysis and Olefin Block Copolymers (OBCs)... 

Keywords Catalyzed olefin polymerization, Chain shuttling catalysis, Chain transfer, Olefin block copolymers, Thermoplastic elastomers... 

Olefin Block Copolymer Production in a Continuous Reactor. 89... 

Table 4 Process details for production of olefin block copolymers using precatalysts 18 and 20 in presence of DEZ...

Despite the potentially stoichiometric nature of the reaction with the CSA, a similar calculation of the number of chains per catalyst molecule reveals that the polymerization is highly catalytic in the hafnium and zirconium species. The chain shuttling methodology is capable of generating unlimited olefin block copolymer chains per catalyst. For example, the synthesis of sample 6 results in formation of -260 chains per total catalyst ... 

The production of olefin block copolymers has been an aspiration of academic researchers and polymer manufacturers alike. Tremendous progress toward this end has been achieved in recent years with the discovery of several designer catalysts capable of living olefin polymerization. However, the stoichiometric nature of the living process, coupled with related process limitations of low polymerization temperatures and slow batch processes, have precluded these approaches from widespread application. 

Well developed is the anionic polymerization for the preparation of olefin/di-olefin - 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 butyl-lithium 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 ... 

M. Zintl, and B. Rieger, Novel Olefin Block Copolymers through Chain-Shuttling Polymerization, Angew. Chem. Int. Ed. 46, 333-335 (2007). 

Insite Not a process, but a range of constrained-geometry metallocene catalysts for polymerizing olefins. Olefin block copolymers made using these catalysts have the trade name Infuse. Developed by J.C. Stevens at the Dow Chemical Company, for which he received several medals. 

It is claimed that styrene/butadiene diblock polymers bring about an improvement in the hardness, strength, and processability of polybutadiene elastomers (27), as well as an improvement in the ozone resistance of neoprene rubber (28). Styrene diblock polymers have also been made with isoprene, a-methyIstyrene, methyl methacrylate, vinylpyridine, and a-olefins. Block copolymers of ethylene, propylene, and other a-olefins with each other have been made as well. Heteroatom block copolymers based on styrene or other hydrocarbons and alkylene oxides, phenylene oxides, lactones, amides, imides, sulfides, or slloxanes have been prepared. 

Chen HY, et al. Olefin block copolymers as polyolefin blend compatibilizer. ANTEC 2007, conference proceedings. Society of Plastics Engineers 2007. 

Y. Lin, G.R. Marchand, A. Hiltner, E. Baer, Adhesion of olefin block copolymers to polypropylene and high density polyethylene and their effectiveness as compatibilizers in blends. Polymer 52, 1635-1644 (2011)... 

Olefin block copolymer (e.g. INFUSE from The Dow Chemical Company)... 

The highest global consumption of any plastic coupled with the many distinct types of commercially available polyethylenes are testament to the rich history of major innovations in products, processes and breadth of applications of polyethylene. This chapter will give a historical perspective of these innovations in polyethylene including a breadth of product applications of polyethylene and the impact of metallocene polyethylenes commercialized in last 15 years. A very recent innovation of olefin block copolymers by The Dow Chemical Company will be described and some remarks will be made on future product innovations and trends. 

Figure 8. Random copolymer versus Olefin Block Copolymer (OBC).

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