High molecular weight polyethers

Commercial thermoplastic polyesters are synthesized in a similar way by the reaction of a relatively high molecular-weight polyether glycol with butanediol and dimethyl terephthalate (14,15). The polyether chain becomes the soft segment in the final product, whereas the terephthaUc acid—butanediol copolymer forms the hard crystalline domains. 

Urethane gels and ultrasoft elastomers are a more recent development.18 They are made primarily by reacting high-molecular-weight polyether polyols with a stoichiometric deficiency of isocyanate. The low NCO-to-OH ratio allows for a wide latitude in hardness adjustment. These low-hardness elastomers are used for seating applications (such as gel bicycle seats), shoe inserts, and soft padding for orthopedic devices. 

When 2,6-dimelhylphenol is oxidized with oxygen in the presence of an amine complex of a copper salt as catalyst a high-molecular weight polyether (PPO) is formed. 

Anionic polymerization is not limited to the vinyl kind, involving addition to carbon-carbon double bonds. Ethylene oxide, for example, is converted by a small amount of base into a high-molecular-weight polyether. 

Fluorination of high molecular weight polyethers with elemental fluorine (diluted with helium) at room temperature gave fluorinated polyethers, which were depolymerized by further treatment with flowing F -He at 55-210 "C to produce carbonyl difluoride, amongst the decomposition products [1197c]. COFj is also formed in the oxidative thermal degradation of polyethers derived from hexafluoropropene oxide [1582]. Polymeric C F Oj decomposes, at an unspecified temperature, into carbonyl difluoride [760], The presence of... 

E. Vandenbergh (1) and with the mode of preparation of different active systems, polynuclear structures are clearly a key feature for the design of catalysts able to polymerize substituted oxlranes into very high molecular weight polyethers. In an exploratory approach based on these premises and aimed at the synthesis of well characterized and versatile specie of that type, we have shown indeed (2) that soluble p-oxo-bimetallic trinuclear alkoxides having the general formula RO) m1-0-m2-0-m1 (OR)0 rank cunong the best known... 

Banter resins, carbon fibers, fatty high molecular weight polyether-potyols. high-nitrile copolymer resins, starch/acrykMMnle copolymer. 

High Molecular Weight Polyether Polyols Based on Polyamine Starters. Autocatalytic Polyether Polyols [148-152]... 

Synthesis of High Molecular Weight Polyether Polyols with Double Metal Cyanide Catalysts (DMC Catalysts)... 

Synthesis of High Molecular Weight Polyether Polyols. .. 

The utilisation of a PO with EO mixture (e.g., with 17-18% EO) strongly diminishes the antifoaming effect of the very high molecular weight polyether formed. 

The structure (6.8) is another type of NAD formed in situ by transfer reaction with the tertiary amine type polyethers. Addition of a high molecular weight polyether initiated by an alkanolamine, ethylene diamine, N-methyl substituted propylene diamine, or N,N dimethyl dipropylene diamines in the polyether polyol used for grafting leads to the formation of very stable polymeric dispersions [37]. The solid fraction has particles of low median diameter (<1.5 pm). The resulting polymer polyols have low viscosities which give good stabilisation of the polymeric dispersion. 

The nonreactive NAD are structures without polymerisable double bonds, but have a remarkable stabilisation effect on polymeric dispersions in polyether media. The main characteristic of such kinds of nonreactive NAD is to have an organic segment with high affinity for the carbocatenary vinylic polymer chemically linked to a high molecular weight polyether chain, which has a high affinity for the continuous liquid polyether matrix. 

One such type of NAD is obtained by the reaction of a crude, alkaline, high molecular weight polyether of 6000 daltons, with a liquid epoxy resin having two epoxy groups (for example diglycidyl ether of bisphenol A). 

A similar structure to the one in Figure 6.6 is obtained by using instead of epoxy resins diphenylmethane diisocyanate (MDI pure or crude ). For example by using crude MDI with the functionality of around 2.2-2.5 -NCO groups/mol, by the reaction with terminal groups of high molecular weight polyether triols (5000-6500 daltons), nonreactive NAD... 

This kind of NAD, resulting from the reaction of crude or pure MDI with high molecular weight polyether triols, is very efficient in stabilising copoly (ACN - styrene) dispersions or even polystyrene dispersions in polyether polyols. 

Very efficient NAD (nonreactive from the point of view of radical polymerisation) are the very high molecular weight polyether polyols (e.g., a polypropylene glycol with a... 

It is well known that with the tertiary amines as catalysts it is impossible to obtain high molecular weight polyether chains (for example polyethers for flexible foams) but with short chain polyethers, having 1-3 alkylene oxide units, it is perfectly possible [31, 32]. 

Polyether polyols for rigid PU foams are obtained in the same type of polymerisation reactors as those used for high molecular weight polyether polyols, i.e., in stainless steel loop reactors, with an external heat exchanger, preferably with the possibility of generating a large surface of the liquid reaction mass, by a spray technique or by an ejector technique... 

Another frequently encountered RLP toughener is a high-molecular-weight polyether from Dyneon LLC (Dynamar HC-1101), an amine-terminated, high viscosity, liquid polymer of molecular weight in the region of 10,000. 

Ultra-high molecular weight polyether GP 18 28 2.3 0.0002 Very Good Excellent... 

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