New method for the synthesis of fully aliphatic telechelic α,ω-dihydroxy-polyisobutylene

• Published in: Polymer chemistry Vol. 5; no. 18; pp. 5436 - 5442
• Main Authors: Castano, Marcela, Becker, Matthew L., Puskas, Judit E.
• Format: Journal Article
• Language: English
• Published: 01.01.2014
• Subjects: Aliphatic compounds; Cleaning; Hexanes; Initiators; Manganese; Polymer chemistry; Premixing; Synthesis
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/C4PY00569D

This paper reports a new method for the synthesis of alpha , omega -primary-dihydroxy PIBs (HO-PIB-OH) with a fully aliphatic backbone. Three aliphatic difunctional initiators with tertiary-methoxy, tertiary-chloride and tertiary-hydroxyl end groups (TMHDiOMe, TMHDiCl and TMHDiOH) were screened in conjunction with TiCl sub(4) and DMA in a solution system (hexane-CH sub(3)Cl, 60/40, v/v). TMHDiOMe yielded only traces of PIB, while TMHDiOH and TMHDiCl yielded PIBs with a mixture of end group structures. The same initiators were also screened in heterogeneous systems (CH sub(3)Cl or CH sub(2)Cl sub(2)). TMHDiOMe/TiCl sub(4) yielded no polymer in either diluent, CH sub(3)Cl, and TMHDiOH/TiCl sub(4) led to olefinic end groups. While TMHDiCl/TiCl sub(4) resulted in clean Cl-PIB-Cl in CH sub(3)Cl, the I sub(eff) values were low and TMHDiCl was very unstable and difficult to isolate. Premixing TMHDiOH with TiCl sub(4) in CH sub(3)Cl led to the in situ formation of TMHDiCl. Addition of hexane and IB, followed by end-capping with allyltrimethylsilane resulted in the formation of allyl-PIB-allyl. Click chemistry with HS-CH sub(2)-CH sub(2)-OH yielded alpha , omega -primary-dihydroxy-PIB (HO-PIB-OH) with M sub(n) = 4085 g mol super(-1) and D sub(M) = 1.2. super(1)H-NMR analysis verified the structure of the HO-PIB-OH.