Polysiloxane copolymers composition

The polyoxyalkylene units in the copolymer have a molecular weight below 500, and the polysiloxane units have 3 to 50 silicon atoms. The resin has a phenol/aldehyde ratio of 2 1 to 1 5 and an average molecular weight of 500 to 20,000 Dalton. The composition shows synergistic demulsification activity when compared with the individual components. The siloxane units can be either in blocks [979,980] of the polyoxyalkylene-polysiloxane copolymer or randomly distributed [728,729]. 

K. Glasgow and N. Alle, Transparent polymeric compositions comprising polysiloxane-polycarbonate copolymer, articles made therefrom and methods of making same, US Patent 7432327, assigned to SABIC Innovative Plastics IP B.V. (Bergen op Zoom, NL), October 7, 2008. 

Many other alkyl-aryl silicones are possible, and some may prove to have mechanical properties superior to those of the two copolymers which have been described. What is needed is a theory of structure of such copolymers which will explain the development of mechanical properties not present in the alkyl or aryl polysiloxanes separately and which thereby will serve as a guide to the formulation of more useful compositions. 

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. 

Recent results of Schnabel [370] do not, however, confirm this view. Copolymers of dimethylsiloxane and phenylmethylsiloxane and copolymers of dimethylsiloxane and diphenylsiloxane of various compositions have been irradiated with 7-rays. Values of GCL were determined for both types of copolymers. With equal concentrations of phenyl groups, the second polysiloxane is less radiation stable than the first, but for both types, the value of Gc L depends linearly on the electron fraction of the dimethylsiloxane units. No protective effect of the phenyl group, in fact, exists. 

This conclusion is confirmed by the data of Finkelmann and Rehage, who examined the optical properties of cholesteric polysiloxanes. These authors revealed that at equal compositions of copolymers the wavelength of selective reflection depends on the length of the spacer binding nematogenic units. 

In some cases, the polysiloxane was in the form of a composite—for example, with sulfonated cross-linked polystyrene particles, carbon black,acrylate latexes,or sodium dodecyl sulfate. Counterintuitively, the addition of impenetrable nanofillers can actually increase the permeability of a membrane. Also, siloxane-imide copolymers have shown some interesting properties in membrane separations, as have polysiloxanes containing poly(ether amine) groups. ... 

Novolac-epoxy netwoiks can be modified with reactive epoxy fimctional polysiloxane oligomers. In accordance with FTIR spectra of the reaction products obtained at various temperatures with an increase of amount of phenol-formaldehyde oligomer in reaction mixture the concentration of epoxy groups decreases rapidly. The composite materials on the basis of organo-inorganic block-copolymers has been obtained and studied. 

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. 

Adams, G., et al. (2000). Polysiloxane block copolymers in topical cosmetic and personal care compositions. In PCT Int. Appl. WO 0071607, Unilever PLC, UK Unilever NV Hindustan Lever Limited, 31 pp. 

Block Copolymers Containing Polysiloxane and Poly(styrene-co-MMA) Segments. Table IV provides results obtained when polymer I was used to initiate polymerizations of styrene, MMA and styrene-MMA mixtures. The H-NMR spectra of the products corresponded well with those of conventional polymers and copolymers having the same composition except for the presence of a signal at -- 0 ppm due to the polysiloxane segments. Exhaustive extraction of the products with hexane failed to remove this component, providing evidence that block copolymers had indeed been formed. 

For polyethers in polysiloxanes, allyl or butyl alcohol (R ) is commonly used as a starting molecule. The most popular monomers for polyethers are ethylene oxide (EO), propylene oxide (PO), and mixtures thereof. The effect of their ratio can be described with the hydrophilic-lipophilic balance (FILB) concept, which will be discussed later [11]. The higher the PO content, the more hydrophobic is the corresponding polyether. Thus, by varying the composition of the polyethers, sometimes denoted as polyoxyalkylene, it is possible to adjust the polarity of the polydimethylsiloxane polyether copolymer. A macroscopic measure for the polarity of both polyethers and polyethersi-loxanes is the cloud point of a 1% aq. solution. The higher it is, the more hydrophilic is the molecule. In this chapter we will denote these compounds as polyethersiloxanes. It is possible to design silicone surfactants that are suitable for aqueous and nonaqueous systems. 

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