Polydimethylsiloxane multiblock

IHu Hu, D., Zheng, S.-X. Morphology and thermomechanical properties of epoxy thermosets modified with polysulfone-block-polydimethylsiloxane multiblock copolymer. J. Appl. Polym. Sci. 119 (2011) 2933-2944. 

Polydimethylsiloxane based multiblock copolymer systems containing 1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene polycarbonate units and phenolphthalein polycarbonate units were synthesized and evaluated231 . Both copolymer systems showed good phase separation, increased rubbery character and improved processa-... 

Multiblock polyethylene-polydimethylsiloxane copolymers were obtained by the reaction of silane terminated PDMS and hydroxyl terminated polyethylene oligomers in the presence of stannous octoate as the catalyst 254). The reactions were conducted in refluxing xylene for 24 hours. PDMS block size was kept constant at 3,200 g/mole, whereas polyethylene segment molecular weights were varied between 1,200 and 6,500 g/mole. Thermal analysis and dynamic mechanical studies of the copolymers showed the formation of two-phase structures with crystalline polyethylene segments. 

Polystyrene-polydimethylsiloxane (PDMS) triblock (or multiblock) copolymers 123) can be made by hydrosilylation involving a vinyl silane terminated polystyrene and a PDMS fitted at both chain ends with Si—H groups. The former species is ob-... 

Copolymers. Copolymers from mixtures of different bisphenols or from mixtures of dichlorosulfone and dichlorobenzophenone have been reported in the patent literature. Bifunctional hydroxyl-terminated polyethersulfone oligomers are prepared readily by the polyetherification reaction simply by providing a suitable excess of the bisphenol. Block copolymers are obtained by reaction of the oligomers with other polymers having end groups capable of reacting with the phenol. Multiblock copolymers of BPA-polysulfone with polysiloxane have been made in this way by reaction with dimethyl amino-terminated polydimethylsiloxane the products are effective impact modifiers for the polyethersulfone (79). Block copolymers with nylon-6 are obtained when chlorine-terminated oligomers, which are prepared by polyetherification with excess dihalosulfone, are used as initiators for polymerization of caprolactam (80). 

Abstract This paper proposes new ways of preparation of hybrid silicones, i.e. an alternated multiblock seqnence of silicone and alkyl spacers, via a polycondensation process catalyzed by the tris(pentaflnorophenyl)borane, a water-tolerant Lewis acid, between methoxy and hydrogeno fnnctionalized silanes and siloxanes at room temperature and in the open air. The protocol was first developed with model molecules which led to polydimethylsiloxane (PDMS) chains, in order to seize the best experimental conditions. Several factors were studied such as the contents of each reactants, the nature of the solvent or the rate of addition. The best conditions were then adapted to the synthesis of hybrid silicones, condensing alkylated oligo-carbosiloxanes with methoxy or hydrogeno chain-ends and complementary small molecules. A systematic limitation in final molar masses of hybrid silicones was observed and explained by the formation of macrocycles, which cannot redistribnte or condense further while formed. 

Random copolyamides are also obtained from MDI or TDI with mixtures of isophthalic acid and 4,4 -oxydibenzoic acid. ° Multiblock copolymers are also obtained by reacting a mixture of isophthalic acid and azelaic acid with MDI to form a prepolymer, which is subsequently reacted with a, ty-bis(10-carboxy-decyl)polydimethylsiloxane. ... 

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