Polysiloxane/polyurethane copolymer

Siloxane containing polyester, poly(alkylene oxide) and polystyrene type copolymers have been used to improve the heat resistance, lubricity and flow properties of epoxy resin powder coatings 43). Thermally stable polyester-polysiloxane segmented copolymers have been shown to improve the flow, antifriction properties and scratch resistance of acrylic based auto repair lacquers 408). Organohydroxy-terminated siloxanes are also effective internal mold release agents in polyurethane reaction injection molding processes 409). 

S—EB—S (compounds) polyurethane/elastomer block copolymers polyester/elastomer block copolymers polyamide/elastomer block copolymers polyetherimide/polysiloxane block copolymers polypropylene/EPDM or EPR blends polypropylene/EPDM dynamic vulcanizates polypropylene/butyl rubber dynamic vulcanizates polypropylene/natural rubber dynamic vulcanizates polypropylene/nitrile rubber dynamic vulcanizates PVC/ nitrile rubber blends... 

Polypropoxy quaternary ammonium chloride Polypropylene glycol fatty acid ester Polysiloxane Polysiloxane Polysiloxane Polyurethane Polyurethane Polyvinyl acetate Polyvinyl acetate Polyvinyl acetate Polyvinyl acetate Polyvinyl acetate Polyvinyl acetate Polyvinyl acetate Polyvinyl acetate/acrylic copolymer... 

Besides the thermoplastic elastomers based on poly(styrene-6-elastomer- -styrene) block copolymers, five others are of commercial importance polyurethane/elastomer block copolymers, polyester/elastomer block copolymers, polyamide/elastomer block copolymers, polyolefin block copolymers, and polyetherimide/polysiloxane block copolymers. All five have the multiblock A-B-A-B. structure. The morphology of the polyurethane, polyester,... 

Hydroxyl-containing silicon material with the hydroxyl groups attached directly to a silicon atom are combined together to react to form silanol-functionalised urethane prepolymers that can cure at ambient temperatures in the presence of moisture to form polysiloxane polyurethanes. For instance, physical blends of a polypropyleneoxide polyol intermediates and an organic-silicone block copolymer-based polyol intermediates have been prepared to improve elongation and reduced... 

Because of the interest in the polyurethane industry with respect to grafting, extensive studies were made on the preparation of polydimethyl sfloxane-polyoxy-alkylene block copolymers by coupling of polyethergtycol and polysiloxanes with functional terminal groups408. ... 

The formation of cellular products also requires surfactants to facilitate the formation of small bubbles necessary for a fine cel] structure. The most effective surfactants are polyoxyalkylene-polysiloxane copolymers. The physical properties of polyurethanes are derived from their molecular structure and determined by the choice of building blocks as well as the suprainolecular structures caused by atomic interaction between chains. The ability to crystallize, the flexibility of the chains, and spacing of polar groups are of considerable importance, especially in linear thermoplastic materials. In rigid cross-linked systems, e.g., polyurethane foains, other factors such as density determine the final properties. 

Hohberg T, Schaefer O, Mueller J et al. (2003) Textiles coated or finished with polysiloxane-polyurea-polyurethane block copolymers (Wacker-Chemie G.m.b.H., Germany) EP1336683. 

Not all copolymers which are produced by step-growth processes are random in nature. Block copolymers are also of major interest. An example of the synthesis of elastic polyurethane fibers was given in Section 1.5.4. Block and graft copolymers of polysiloxane-poly(alkylenc ethers) with segments like5-9 are used as surfactants in the production of polyurethane foams with uniform cell sizes. 

The surfactants employed for polyurethane foams can be also used for preparing foamed composites. The surfactants include silicone surfactants, which consist of polysiloxane-polyoxyalkylene block-copolymers. 

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. 

Surfactants based on block copolymers of dimethylsilicone and poly(ethylene oxide) are unique in regulating the cell size in polyurethane foams. One route to such polymers used the reaction between a polysiloxane and an allyl ether of poly(ethylene oxide). 

High density polyethylene (HDPE) Polycarbonate (PC) Polyvinyl chloride (PVC) Polystyrene (PS) Polyurethane (PUR) Polyurea + PUR Low density polyethylene ethyl + vinyl acetate (LDPE + EVA) Polyvinyl acetate (PVA) Acrylonitrile-styrene-butadiene (ABS) Acrylonitrile-styrene copolymer (AS) Styrene-butadiene-styrene (SBS) Polysiloxane Gelatin/arabic gum (G/AG)... 

Jiang, H. Zheng, Z. Song, W. Li, Z. Wang, X., Alkoxysdane Functionalized Polyurethane/Polysiloxane Copolymers Synthesis and the Effect of End-Capping Agents. Polym. Bull. 2007,59,53-63. 

Cross-linking can be done by various techniques depending on the chemical composition of the polymer. Thus, if the polymer contains C=C unsaturation, e.g. in polydienes, natural rubber, polyisobutylenes (from copolymerized isoprene), then reaction with sulphur forms —S—S— links. With polysiloxanes or EP rubbers (no C=C) then peroxides are used. With fluorocarbon elastomers, e.g. Viton (a copolymer of vinylidene difluoride and hexafluoropropylene), diamines are used which form H-bonded cross-links. With polyurethanes (formed from diols and di-isocyanates) a controlled number (low) of cross-links are formed during the polymerization by the addition of triols. 

The most widely used elastomers are natural rubber [17], synthetic polyisoprene and butadiene rubbers, styrene-butadiene copolymers, ethylene-propylene rubber (specifically EPDM), butyl and halobutyl elastomers, polyurethanes, polysiloxanes, polychloroprenes, nitrile rubber, polyacrylic rubbers, fluorocarbon elastomers, and thermoplastic elastomers [18-20]. The examples which have unsaturation present in the repeat units (such as, the diene elastomers) have the advantage of easy cross-linkability, but the disadvantage of increased vulnerability to attack by reactants, such as oxygen and ozone. 

Hazzi2a-Laskar et al. modified polysUoxane 62 to a polysiloxane that contained a primary alcohol and quaternary ammounium group 65 side chain. Polymer 65 was modified further to a siloxane-based side-chain polyurethane 66 (Scheme 24). This copolymer (3) had potential as a biocide. 

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