Polymer modification containing precursor polymers with

Another class of silicon-containing polymers that have great potential to be extremely useful precursor materials are poly(chlorocarbosilanes).14f 46 Poly (chlorocarbosilanes) are not useful without modification because of the rapid hydrolysis of Si—Cl bonds, forming HC1 and an insoluble crosslinked polymer network. However, nucleophilic substitution of these Si—Cl bonds with various reagents produces materials widi a broad range of properties that are determined by the nature of the nucleophile used.47 Poly(chlorocarbosilanes) can be easily synthesized by ADMET (Fig. 8.18) without any detrimental side reactions, since the Si—Cl bond is inert to both catalysts 12 and 14. Early studies produced a polymer with Mn = 3000.14f... 

Polymer Modification of the =Si—H Containing Precursor Polymers With Dimethyldioxirane... 

A new convenient polymer modification for the conversion of the Si—H to Si—OH by the selective oxidation of the Si—H bond by dimethyldioxirane has been described. The oxyfunctionalization of the silane precursor polymers proceeded rapidly and quantitatively and can be applied to the synthesis of a wide variety of novel silanol polymers with specific properties from the corresponding precursor polymers containing Si—H functional groups. Control over the properties of these silanol polymers, such as reactivity and self-association of silanols, was realized through the placement of different substitute groups bonded directly to the silicon atom and by the variation of silanol composition in a copolymer. These novel silanol polymers with a... 

In the synthesis of polymers with functional groups suitable for drug attachments, hydrophilic hydroxyl-containing polymers and copolymers of divinyl ether and maleic anhydride are commonly used as precursor backbones for further modification. Polyfvinyl alcohol) has also been used in this way, both as the starting point for enzyme immobilization work, sometimes via azido group reactions, and also as a precursor for new membranes of potential interest in the haemodialysis field. ... 

A new convenient polymer modification has been developed to synthesize a series of novel silanol-containing polymers by a selective oxidation of Si—containing precursor polymers with a dimethyldioxirane solution in acetone. The silanol hydrogen bonding interactions in polymer blends as well as the silanol self-condensation to form siloxane semi-interpenetrating polymer networks in miscible polymer blends and organic-inorganic polymeric hybrids are discussed. 

Polymer Modification of the sSi—Containing Precursor Polymers with a Dimethyldioxirane solution in acetone. To a methyl ethyl ketone solution of sSi—H containing precursor polymers or copolymers, a cold solution (ca. -10 °C) of dimethyldioxirane in acetone was quickly added and reacted for 30 min at 0 °C. The mole ratio of dioxirane to polymer was ca. 1.2 1.3. The resulting silanol polymers or copolymers were obtained either in solution and used as is or precipitated into hexane followed by vacuum drying at 40 °C for 24 h. 

Another polyester type, i.e., polycarbonate, is rather seldom solvolytically depolymerized because of losing (at least partially) carbonate groups/bonds obtained via phosgene route synthesis. Troev et al. [29] recently described PC chemical degradation with dialkyl phosphonates (dimethyl or diethyl) or triethyl phosphate. The products, oligomeric carbonates containing phosphorus atoms, can be considered as precursors for the modification of various polymers by improving their flame-retardant properties, thermal stability, and adhesion. 

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