Premium
In situ copolymerization of ethylene to produce linear low‐density polyethylene by Ti(OBu) 4 /AlEt 3 ‐MAO/SiO 2 /Et(Ind) 2 ZrCl 2
Author(s) -
Zhu Bochao,
Guo Cunyue,
Liu Zhongyang,
Yin Yuanqi
Publication year - 2004
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.21190
Subject(s) - polyethylene , linear low density polyethylene , ethylene , crystallinity , polymer chemistry , metallocene , branching (polymer chemistry) , catalysis , polymerization , ziegler–natta catalyst , copolymer , materials science , butene , hexene , molar mass distribution , 1 butene , low density polyethylene , propene , post metallocene catalyst , polymer , chemistry , organic chemistry , composite material
Linear low‐density polyethylene (LLDPE) is produced in a reactor from single ethylene feed by combining Ti(OBu) 4 /AlEt 3 , capable of forming α‐olefins (predominantly 1‐butene), with SiO 2 ‐supported Et(Ind) 2 ZrCl 2 (denoted MAO/SiO 2 /Et(Ind) 2 ZrCl 2 ), which is able to copolymerize ethylene and 1‐butene in situ with little interference in the dual‐functional catalytic system. The two catalysts in the dual‐functional catalytic system match well because of the employment of triethylaluminum (AlEt 3 ) as the single cocatalyst to both Ti(OBu) 4 and MAO/SiO 2 /Et(Ind) 2 ZrCl 2 , exhibiting high polymerization activity and improved properties of the obtained polyethylene. There is a noticeable increment in catalytic activity when the amount of Ti(OBu) 4 in the reactor increases and 1‐butene can be incorporated by about 6.51 mol % in the backbone of polyethylene chains at the highest Ti(OBu) 4 concentration in the feed. The molecular weights ( M w ), melting points, and crystallinity of the LLDPE descend as the amount of Ti(OBu) 4 decreases, which is attributed mainly to chain termination and high branching degree, while the molecular weight distribution remains within a narrow range as in the case of metallocene catalysts. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2451–2455, 2004