Catalyst system for polymerization of olefinic monomers, process for preparing polymers, and polymers prepared by the process

Supported catalyst system for polymerization of olefins, comprising:

• a support made of fibers or a fleece of fibers, wherein the mean fiber diameter is less than 1000 nm and the mean fiber length is more than 200,000 nm, the support comprising a transition metal compound,
• at least one organometallic compound supported on the fiber support, the organometallic compound being selected from organometallic compounds of formula I:
• M1(R11)r(R12)s(R13)t (I)
• where
• M1 is an element of a main group of the Periodic Table of the Elements,
• R11 is hydrogen, C1-C10-alkyl, C6-C15-aryl, halo-C1-C10-alkyl, halo-C6-C15-aryl, C7-C40-arylalkyl, C7-C40-alkylaryl, C1-C10-alkoxy or halo-C7-C40-alkylaryl, halo-C7-C40-arylalkyl or halo-C1-C10-alkoxy,
• R12 and R13 are each hydrogen, halogen, C1-C10-alkyl, C6-C15-aryl, halo-C1-C10-alkyl, halo-C6-C15-aryl, C7-C40-arylalkyl, C7-C40-alkylaryl, C1-C10-alkoxy or halo-C7-C40-alkylaryl, halo-C7-C40-arylalkyl or halo-C1-C10-alkoxy,
• r is an integer from 1 to 3
• and
• s and t are integers from 0 to 2, with the sum r+s+t corresponding to the valence of M1,
• or aluminoxane compounds of formula II or III:
• where R21-R24 are each, independently of one another, a C1-C6-alkyl group.