Thermal cyclopolymerization

Recently, Jen s group synthesized a series of high Tg fluorinated polymers with a hole transporting TPA group covalently attached as side chains (55) (Scheme 3.21) [99]. This type of polymer can be processed into thin films by simple thermal cyclopolymerization without introducing any by-products [100]. The polymers (56, 57) are insoluble in most organic solvents and can be conveniently streamlined into a multilayer device fabrication process [101,102]. The... 

Sol-gel and PU oligomerization reactions require a strict control of the reaction conditions, because atmospheric moisture can negatively influence the reaction, causing phase separation and optical loss. To tackle this problem, a new cross-linking unit, trifluorovinyl ether (TFVE), has been introduced. TFVE-containing monomeric units can be converted into perfluorocyclobutane (PFCB) containing polymers by a radical-mediated thermal cyclopolymerization reaction. These polymers have excellent properties such as a low dielectric constant, good thermal stability, and optical transparency [99]. 

He et al. have prepared phosphonated aiyl trifluorovinyl ethers containing flexible oligo(ethylene oxide) units and subsequently homopolymerized these monomers by thermal cyclopolymerization in bulk at 180 °C. The resulting polymer was treated with bromotrimethylsilane to obtain the phosphonic acid derivative. The phosphonated trifluorovinyl ether monomers were also copolymerized with tetrafluoroethylene via free radical pol3Tnerization in an autoclave at 70 °C using l,l,2-trichloro-l,2,2-tri-fluoroethane as solvent. Moreover, radical terpolymerizations of the same trifluorovinyl ether monomers were performed with mixtures of... 

Perfluorocyclobutane (PFCB) polyaryl ethers are one such class of partially fluorinated polymers which combine the processability and durability of engineering thermoplastics with the optical, electrical, thermal, and chemical resistant properties of traditional fluoroplastics. Developed originally at The Dow Chemical Company" in Freeport, TX, PFCB polymers are prepared by the radical mediated thermal cyclopolymerization of trifluorovinyl ethers (Figure 1) and have, to date, provided a variety of thermoplastic and thermosetting materials possessing a tunable range of... 

Milne [5] prepared polypyrrolidine, (Vlll), by the cyclopolymerization of 1,10-(di-MV-diallyl)decane by UV or thermal radiation. 

Cross-linking involving cyclopolymerization or polycyclotrimerization of the aromatic nitrile in the precursor is accomplished by thermal curing as illustrated by the following reaction ... 

Perfluorinated dioxole monomers have been used to prepare a series of amorphous fluoropolymers such as Teflon AF and Hyflon AD. A third amorphous fluoropo-lymer, Cytop contains perfluorotetrahydrofuran and perfluorotetrahydropyran rings, but is prepared in a cyclopolymerization process from an acyclic monomer. These amorphous fluoropolymers retain the outstanding chemical, thermal, and surface properties associated with perfluorinated polymers while also having unique electrical, optical, and solubility characteristics. 

It follows from this reasoning that aromatic polymers will have greater thermal stability. For example, poly(p-phenylene) synthesized by stereospecific 1,4-cyclopolymerization of cyclohexadiene, followed by dehydrogenation ... 

NBE dicarboximides and subsequent cyclopolymerization of Meldrum s acid-containing 1,6-hexadiynes (72) were reported by Choi et al. [46] (Scheme 9.11b). The prepared polymers assembled in core-shell supramolecules (nanospheres), with the inner core being the insoluble polyacetylene block functionalized with Meldrum s acid. Thermal treatment at 240 °C for 10 min led to cross-linking of the inner core (74) by ketene dimerization (Scheme 9.11c). 

Babb, D. A. Snelgrove, R. V. Smith, D. W., Jr. Mudrich, S. F. Novel Step-Growth Polymers from the Thermal (2p - -2pj Cyclopolymerization of Aryl Trifluorovinyl Ether Monomers-, ACS Symposium Series ACS Publications, 1996 pp 431 41. 

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