Abstract
AbstractThe influence of ethyl benzoate (E.B.) on the copolymerization of styrene with 1‐hexene, initiated by isospecific Ziegler‐Natta catalysts α‐TiCl3(H)‐AlEt3 and TiCl3 · 1/3 AlCl3‐AlEt3 (mole ratio Al/Ti = 3), was examined. Ethyl benzoate was found to reduce the activity of the catalysts. In addition it leads, depending on the Ti catalyst, to opposite effects on the apparent reactivity order of the two monomers. Incorporation of styrene into the copolymers is reduced when E. B. is added to TiCl3 · 1/3 AlCl3‐AlEt3. On the contrary, a much higher incorporation of styrene is observed with α‐TiCl3(H)‐AlEt3 in the presence of E. B. For this system the calculated reactivity ratio varies strongly with increasing proportion of E. B.: for a mole ratio AlEt3/E. B. = 3, rS = 0,94 and rH = 1,46 and for AlEt3/E. B. = 2, rS = 8 and rH = 0,1. Changes in the stereoregularity of copolymers suggest that E. B. leads to an inhibition of the less stereospecific sites for TiCl3 · 1/3 AlCl3‐AlEt3, whereas its addition suppresses the stereospecificity of the α‐TiCl3(H)‐AlEt3 catalyst. Contributions of conventional cationic and/or radical processes to the copolymerization reaction were examined and may be ruled out.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
