Polytetrahydrofuran/poly copolymer

A survey Is given of the methods developed to synthesize novel block copolymers In which at least one of the polymer segments Is polytetrahydrofuran (poly THF). The techniques covered Include the use of transformation reactions, direct reaction between living polymers and quaternlzatlon of performed polymers. The relative efficiencies of these synthetic routes are discussed. 

Feng, X.S. and Pan, C.Y. (2002) Block and star block copolymers by mechanism transformation. 7. Synthesis of polytetrahydrofuran/poly(l,3-dioxepane)/polystyrene ABC miktoarm star copolymers by combination of CROP and ATRP. Macromolecules, 35,2084—2089. 

Two PBT based thermoplastic elastomers were studied. One was a PBT-polytetrahydrofuran (pTHF) copolymer (PECO-1) and the other one a PBT-poly(propylene glycol) (PPG) copolymer (PECO-2). In both cases the degradations were done on 30 pm thick films. All of these polymers were supplied by DSM Engineering Plastics. 

PBT and its Polytetrahydrofuran (PECO-1) or Poly(propylene glycol) (PECO-2) Copolymer... 

In Chapter 3, the chemistry and technology of the most important oligo-polyols used for elastic polyurethanes fabrication, in fact high MW oligomers (2000-12000 daltons) with terminal hydroxyl groups and low functionality (2-4 hydroxyl groups/mol) were discussed. Polyalkylene oxide polyols (homopolymers of PO or copolymers PO - EO, random or block copolymers), polytetrahydrofuran polyols, filled polyols (graft poly ether polyols, poly Harnstoff dispersion - polyurea dispersions (PHD) and polyisocyanate poly addition (PIPA) polyols), polybutadiene polyols and polysiloxane polyols were all discussed. The elastic polyurethanes represent around 72% of the total polyurethanes produced worldwide. 

Anionic polymerization frequently has been used to prepare well-defined living polymers such as polystyrene, poly(a-methylstyrene), polydienes, which may be transformed by two methods into block copolymers with cationically polymerizable monomers. When a living anionic polymer is mixed with a stoichiometric amount of a living cationic polymer the cationic and anionic species may couple. For example, anionic living polystyrene (St) or poly (a-methylstyrene) (MSt) were reacted with living cationic polytetrahydrofuran (THF). In the latter system the coupling efficiency was low, probably because of proton or hydride transfer 132) ... 

The direct coupling of preformed living blocks (usually cation and anion or group transfer) also enables the formation of block copolymers, such as polytetrahydrofuran-b-polystyrene-b-polytetrahydrofuran [13], polystyrene-b-polytetrahydrofuran [14], polystyrene-b-poly(ethyl vinyl ether) [15], poly(methyl methacrylate)-b-polytetrahydrofuran [16], poly[0-(jS-D- glucopyranosyl)-L-serine]-b-poly(2-methyl-2-oxazoline) [8], poly(methyl methacrylate)-b-poly(butyl vinyl ether) [17], polyisobutylene-b-poly(vinyl ferrocene), and poly(vinyl ferrocene)-polyisobutylene-b-poly(vinyl ferrocene) [18]. A typical example of such a coupling process between oppositely charged macroions is presented in Scheme 11.1, for the preparation of polystyrene-b-poly(ethyl vinyl ether) [15]. 

A comparison of the phase behaviour of PEO/PPO and PEO/PBO copolymers in butanol/water was recently reported (170). (Note that in this paper, poly(butylene oxide) is referred to as polytetrahydrofuran.) Pluronic FI27 , E100P70E100, exhibits Li, L2, Ii, Hi and phases. The Li phase exists along the polymer-water axis up to 20% polymer, accommodating up to 10% butanol. The I) cubic phase supercedes the Li phase and exists up to 65% polymer. Its ability to solubilize butanol decreases with increasing polymer concentration. The Hi phase is formed at above 20% polymer, although at least 15% butanol is required for it to form. A maximum of 23% butanol can be accommodated in the Hi phase. As the polymer concentration is increased, the butanol concentration required to form the Hi phase decreases,... 

A living cationic polymerization of tetrahydrofuran, using BH3 as the initiator in the presence of epichlorohydrin and 3,3-bis(chloromethyl)oxacyclo-butane [348], results in formation of block copolymers. Two types form. One is an A—B type. It consists of polytetrahydrofuran blocks attached to blocks of poly(3,3-bis(chloromethyl)oxacyclo-butane). The other one is an A— AB— B type [348]. 

Common SS include polyethers, polyesters and polyalkyl glycols with glass transition temperatures in the range of -70°to -30°C. Commonly used macrodiols in the PUs synthesis are polyalkyl-diols, such as polyisobutylene diol [70], polybutadiene (PBU) [20, 71], or oligo-butadiene diols [72] as well as hydrogenated polybutadiene diol [20] polyether diols polytetrahydrofuran (PTHF or PTMO) [50-52], polyethylene glycol (PEG) or (PEO) [73], polypropyleneoxide (PPO) [73] or mixed blocks of them PEO-PPO-PEO [74] and PPO-THF [54] polyester diols poly(ethylene adipate) (PEA) [4,20], poly(butylene adipate) (PBA) [20, 73], and latterly polycaprolactone diol (PCL or PCD) [75], polyalkylcarbonate polyol [20] or mixed blocks of them, for example poly(carbonate-co-ester)diol [76], poly(hexamethylene-carbonate)diol [77], as well as poly(hexamethylene-carbonate-co-caprolactone)diol [78] and a mixed block copolymer of polyether and polyester blocks PCL-b-PTHF-b-PCL [79]. Examples schemes of macrodiols are shown in Eig. 1.9. 

Poly (thiophene)s are of particular interest as electfochromic materials owing to their chemical stability, ease of synthesis and processability. For the most part, current research has been focused on composites, blends and copolymer formations of several conjugated polyheterocyclics, polythiophene and its derivatives, especially PEIX)T. In one example, poly(3,4-ethylenedioxythiophene) (PEDOT)/poly(2-acrylamido-2-methyl-l-propanesulfonate) (PAMPS) composite films were prepared by Sonmez et al. for alternative electrochromic applications [50]. Thin composite films comprised of PEDOT/PAMPS were reported to switch rapidly between oxidized and neufial states, in less than 0.4 s, with an initial optical contrast of 76% at A.max. 615 nm. Nanostructured blends of electrochromic polymers such as polypyrrole and poly(3,4-ethylenedioxythiophene) were developed via self-assembly by Inganas etal. for application as an electrochromic window [26]. Uniir etal. developed a graft-type electrochromic copolymer of polythiophene and polytetrahydrofuran for use in elecfiochromic devices [51]. Two EDOT-based copolymers, poly[(3,4-ethylenedioxythiophene)-aZ/-(2,5-dioctyloxyphenylene)] and poly[(3,4-ethylenedioxythiophene)-aft-(9,9 -dioctylfluorene)] were developed by Aubert et al. as other candidates for electrochromic device development [52],... 

Block copolymers (see Chapter 17) in which polytetrahydrofuran and bisphenol A were used as polyols have been described (Merrill, 1961) whilst a similar type of material based on a polyoxyethylene system has been prepared (Goldberg, 1%3). More recently (Perry et al., 1965) have described interesting materials in which blends of a poly(tetramethylene ether)glycol and a highly cyclic glycol were... 

Thermal stability measurements have been carried out on numerous other polymers including polyethylene ethylene vinyl-alcohol copolymer [12], polyaniline [13], ) 3 s-stilbene-N-substituted maleimides [14], cellulose [15-20], polystyrene [14, 16], ethylene-styrene copolymers [21,22], ST-DVB-based ion exchangers [23], vinyl chloride-acrylonitrile copolymers [24], polyethylene terephthalate [25], polyesters such as polyisopropylene carboxylate [26], polyglycollate [27-29], Nylon 6 [30], polypyromellitimides, poly-N-a-naphthylmaleimides [26,31], polybenzo-bis(amino-imino pyrolenes) [32], polyvinyl chloride [33-35], acrylamide-acrylate copolymers and polyacrylic anhydride [36-38], polyamides [39], amine-based polybenzo-oxazines [40], polyester hydrazides [41], poly-a-methyl styrene tricarbonyl chromimn [42], polytetrahydrofuran [43], polyhexylisocyanate [44], polyurethanes [45], ethylene-... 

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