THE STOPPED-FLOW TECHNIQUE FOR 1-ALKENE POLYMERIZATION

abstract

English

The stopped-flow polymerization technique enables to study early stages of a-olefin polymerization on Ziegler-Natta or metallocene catalysts. This technique allows performing the polymerization experiments shorter than average lifetime of the growing polymer chains (ca. 0.2 s). Thus the stopped-flow technique is considered as one of the most powerful tool for the investigation of the catalyst active sites performance and elucidation of the olefin polymerization mechanism based on the analysis of obtained polymer material. In this work the stopped-flow technique is further utilized for the development and preparation of new polymer materials based on the preparation of special block copolymers as polypropen-block-poly(propen-co-ethen). For this purpose, the new experimental facility suitable for the preparation of relatively high amount of the copolymer materials was constructed. The facility is designed for the copolymer synthesis close to the conditions applied in industry (polymerization pressure up to 2.2 MPa, polymerization temperature up to 70C), what facilitates the product preparation. Successful preparation of block copolymers will provide a new insight on the nature of active sites presented in the heterogeneous Ziegler-Natta catalysts and also allow investigating the role of block copolymers in heterogeneous materials consisting of crystalline matrix (polypropen) with inclusions of amorphous poly(ethen-co-propen) rubber (impact resistant sequential copolymers produced by commercial two-reactor technology).

stoped-flow, polypropylene

HOZA, A.; CEJPEK, I.; SKOUMAL, M.; KRATOCHVÍLA, J.

17. 8. 2011

0009-2770

Chemické listy

105

18

Czech Republic