Metallocene/Borate-Catalyzed Copolymerization of 5-N,N-Diisopropylamino-1-pentene with 1-Hexene or 4-Methyl-1-pentene

• Published in: Macromolecules 1999-01, Vol.32 (1), p.14-20
• Main Authors: Stehling, Udo M., Stein, Kevin M., Fischer, David, Waymouth, Robert M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Copolymerization; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma980856c

Metallocene/borate catalysts, generated from zirconocene dimethyl compounds, L n ZrMe2, and anilinium borate, [HNMe2Ph]+[B(C6F5)4]-, were used to copolymerize 5-N,N-diisopropylamino-1-pentene with 1-hexene and 4-methyl-1-pentene. The selected zirconocenes, bis(pentamethylcyclopentadienyl)zirconium(IV) dimethyl (Cp*2ZrMe2) and rac-ethylenebis(4,5,6,7-tetrahydroindenyl)zirconium(IV) dimethyl (rac-EB(THI)ZrMe2), provided atactic and isotactic materials, respectively. The isotactic polymers produced were amorphous or crystalline depending of the monomer. The calculated reactivity ratios for the copolymerization of 5-N,N-diisopropylamino-1-pentene with 1-hexene and metallocene rac-EB(THI)ZrMe2 indicate that this system approximates an ideal azeotropic copolymerization with r 1 = 1.11 and r 2 = 0.87. Estimates for the reactivity ratios for the copolymerization of 5-N,N-diisopropylamino-1-pentene with 4-methyl-1-pentene were r 1 = 3 and r 2 = 1 for rac-EB(THI)ZrMe2 and r 1 = 5 and r 2 = 0.5 for Cp*2ZrMe2. The polymerization of 1-hexene in the presence of the saturated 1-N,N-diisopropylaminopentane with rac-EB(THI)ZrMe2/borate was compared with analogous copolymerizations of 1-hexene/5-N,N-diisopropylamino-1-pentene. The aminopentene was more effective than the aminopentane in inhibiting the rate of total monomer conversion, implicating both intra- and intermolecular mechanisms for inhibition by the amine. Copolymers of 4-methyl-1-pentene/5-N,N-diisopropylamino-1-pentene produced with rac-ethylenebisindenyl zirconium(IV) dimethyl (rac-EBIZrMe2)/borate have higher decomposition temperatures with increasing amounts of aminopentene. This copolymer can be protonated with HCl to yield a methanol-soluble material.