Telechelic polyisobutylenes, synthesis

The same chemistry was used for the three-arm star telechelic polyisobutylene synthesis (171). These two functional groups (that is, propenyl and hydroxyl) afford the possibility of almost any kind of functional groups to be introduced at the chain ends of polyisobutylene. By derivation of hydroxyl and propenyl terminated polyisobutylene, telechelics containing carboxylic (191. 192), -SiCl and H-SiH (193. 19A). acryloyl and methacryloyl (195). 

J. Feldthusen, B. Iv n, A.H.E. Muller, and J. Kops, Synthesis of linear and three-arm star tert-chlorine-telechelic polyisobutylenes by a two-step conventional laboratory process, Macromol. Rapid Commun., 18(5) 417-425,1997. 

Fundamental studies directed toward the elucidation of the mechanism of olefin i.e.f isobutylene, polymerizations yielded a new method for the synthesis of novel linear and tri-arm star telechelic polymers and oligomers [1,2]. The synthesis involves the use of bi- or tri-functional initiator/transfer agents, so called inifers (binifers and trinifers), in conjunction with BCI3 coinitiator and isobutylene, and gives rise to polyisobutylenes carrying exactly two or three terminal -CH2-C(CH3)2Cl groups. These liquid telechelic polyisobutylene chlorides can be readily and quantitatively converted to telechelic polyisobutylene di- or tri-olefins [2,3] which in turn can quantitatively yield by hydroboration/oxidation telechelic polyisobutylene di- and triols [4,5]. 

This paper concerns the synthesis of a new telechelic polyisobutylene diol, a, a)-di (hydroxy) po lyi so-butylene (formula IV in Scheme I), and the preparation of new linear polyurethanes containing polyisobutylene (PIB) soft segments by the use of this diol and conv-ventional extension techniques with TDI. 

A. Synthesis of Linear Telechelic Polyisobutylene Diols. According to model calculations [5-7] efficient chain extension of telechelics can be carried out only with prepolymers having (number average... 

Synthesis and Characterization of a-Hydroxyl-a>-Methoxycarhonyl and oc-Hydroxyl (D>Carhoxyl Asynunetric Telechelic Polyisobutylenes... 

Quenching of living carbocationic polymerization also leads to tert-chlorine-telechelic polyisobutylenes (222). Synthesis of mono- (223-226), di- (227-235), tri- (236), and tetrafianctional (237) polyisobutylenes carrying Cl termini was reported. 

Figure 3.5 Attachment of complex hydrogen-bonding systems to bis-telechelic PIB prepared by LCCR (Reprinted with permission from W.H. Binder, MJ. Kunz, C. Kluger et aL, Synthesis and analysis of telechelic polyisobutylenes for hydrogen-bonded supramolecular pseudo-block copolymers, Macromolecules, 37, 5, 1749-1759, 2004. 2004 American Chemical Society.)...

J.P. Kennedy and R.A. Smith, New telechelic polymers and sequential copolymers by polyfunctional initiator-transfer agents (inifers). II. Synthesis and characterization of a, a>-di(ferf-chloro)polyisobutylenes,. Polym. Sci., Part A Polym. Chem., 18(5) 1523-1537,1980. 

The Inifer Method. A special case of controlled initiation is the inifer method (17). The word inifer (from initiator trans/t / agents) describes compounds that function simultaneously as initiators and as chain-transfer agents. Chain transfer to inifer regenerates R+. The inifer technique provided the first carbocationic route toward the synthesis of telechelic (a,G) functional) polyisobutylenes and more recendy telechelic poly( >-chlorostyrenes) (18). To prepare telechelic products chain transfer to monomer must be absent, and with BC13 as coinitiator this requirement is fulfilled. 

The first part concludes with a discussion of the similarity between the mechanisms of initiation and chain transfer, the appreciation of which led to the inifer concept, which in turn yielded new telechelics, networks, sequential copolymers, etc. The second part of this presentation focuses on practical consequences of understanding details of the mechanism of initiation. The synthesis of a new family of telechelic linear and tri-arm star polyisobutylenes will be described. Among the new prepolymers are telechelic olefins, epoxides, aldehydes, alcohols, and amines. The preparation of new ionomers and polyisobutylene-based polyurethanes will be outlined and some fundamental properties of these new materials will be discussed. 

Synthesis of poly(methyl methacrylate)"b-polyisobutylene-b-poly(methyl methacrylate) (PMMA-b-PIB-b-PMMA) triblock copolymers was also performed (see Table I). First, a series of DPE-capped telechelic PIBs were prepared by using a difiinctional initiator (tBuDiCumCl) for LCCP of IB. 

Preparations of macro-initiators or telechelic polymers by cationic methods have been executed primarily by polymerizing isobutylene in the presence of a co-initiator that also functions as a chain transfer agent. A typical reaction sequence is shown in Scheme 1, outlining the synthesis of difunctional polyisobutylene (PIB), which is then used to initiate the polymerization of a-methyl styrene (ffi-MS) to produce an A-B-A type block copolymer. By similar methods, polyisobutylenes with phenol, phenyl, cyclopentadiene, and olefin termini have been synthesized. 

Ivan, B. and Kennedy, J.P. (1990) Living carbocationic polymerization. XXX. One-pot synthesis of allyl-terminated linear and tri-arm star polyisobutylenes, and epoxy- and hydro xy-telechelics thereftom. Journal of Polymer Science Part A Polymer Chemistry, 28,89-104. 

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