Graft copolymers grafting method

Ti-SBA-15 Grafting method. SBA-15 prepared first using the amphiphilic triblock copolymer poly(ethyleneox-ide) -poly (propyleneoxide) -poly (ethyleneoxide) (EO-PO-EO) as template and TEOS as Si source. The composition was 2 g copolymer 0.021 mol TEOS 0.12 mol HC1 3.33 mol H20. The solid was calcined at 600 K for 4 h to remove the copolymer. Ti in the form of titanium isopropoxide was grafted onto the dehydrated surface of SBA-15 Pore diameter = 6.3 nm, surface area = 518 m2/g, pore volume = 0.68 (25)... 

Recently this grafting methods has been used to synthesize amphiphilic graft copolymers in which hydrophilic grafts are linked to a hydrophobic backbone. Partly chloromethylated polystyrene is used to deactivate either monofunctional "living" polyethylene oxide or monofunctional "living" polyvinylpyridine. In the latter case subsequent quaternization yields polyelectrolyte grafts. ... 

Graft Copolymers via Polymeric Azo Initiators 3.1 Grafting Methods... 

The interest in radiation grafting lies in the fact that it is on route to the production of an almost unlimited range of new materials by an easy and clean method. If can be carried out in gels, in semi-solid substances and even in the bulk or on the surface of shaped products. At the time of these early findings, chemical grafting methods were scarce and were conducted in dilute solutions with very low yields of graft copolymers. This explains why these studies produced such a strong impact on radiation research. 

Recently Dreyfuss et al. (113, 114) developed a new method for the determination of the number of poly(THF) branches in a graft copolymer. The method is based on the termination of the living cationic chain ends with NH OH-NH Cl buffer and reaction with fluorescamine. The chain ends concentration is determined by fluorescent spectroscopy. 

Radical functionalization of iPP with acrylic acid (AA) gives iPP-AA, which acts as a compatibilizer for PP/liquid crystal polyblend fibers and increases fiber crystallinity and interfacial adhesion. " The reaction of PP with maleic anhydride in xylene at elevated temperatures (120 °C) in the presence of benzoyl peroxide gives maleated iPP. Co-melting of this material with poly(e-caprolactone) (PCL) for 6 h at 120 °C gave a PP-g-PCL graft copolymer. Similar methods have been employed for the grafting of A-phenylmaleimide and maleimido benzoic acid onto iPP oligomers in order to... 

Graft copolymers containing styrene in the main chain and other monomers in their side chains are available by numerous methods, including conventional radical [171], controlled radical, anionic [174], and cationic [175] polymerization and by copolymerization of macromonomers [80,174], Grafting methods via conventional radical polymerization are reviewed by Nuyken and Weidner [171], The following reaction scheme demonstrates the principles and universality of the methods applying polymeric initiators ... 

Rubber vulcanization crosslinking was an early chemical modification method. Block and graft methods are also widely used in polymer modification. One of the successful examples of a block copolymer is a thermoplastic elastomer. It is a new material that can be processed like plastic and has elasticity like rubber. Among graft copolymers, the most widely used one is the acrylonitrile butadiene and styrene copolymer... 

A variant on the grafting method is to use a diblock copolymer made out of two distinct blocks, as shown in Fig. 3c. The first block is insoluble and is attracted to the substrate, and thus acts as an anchor fixing the chain to the surface it is drawn as a thick line in Fig. 3c. It should be long enough to cause irreversible fixation on the surface. The other block is a soluble one (the buoy ), forming the bmsh layer. For example, fixation on hydrophobic surfaces from a water solution can be made using a polystyrene-poly(ethylene oxide) (PS-PEO) diblock copolymer. The PS block is insoluble in water and is attracted towards the substrate, whereas the PEO forms the brush layer. The process of diblock copolymer fixation... 

Figure 18 Effects of solution and grafting method on morphological structures of cotton cellulose-polyacrylonitrile copolymers as shown by electron microphotographs of fibrous copolymer cross-sections (a) cerium(IV) chelate initiation with acrylonitrile dissolved in water (b) immersion high-energy-irradiated cellulose fiber in acrylonitrile (32%) in 80% aqueous ZnCl2 (c) immersion of cellulose fiber in solution as in (b) then high-energy irradiation (d) immersion of cellulose fiber in acrylonitrile (15%) in 75% aqueous ZnClj then high-energy irradiation (e) cyanoethylation of cellulose fiber to yield...

Acrylonitrile—Butadiene—Styrene. ABS is an important commercial polymer, with numerous apphcations. In the late 1950s, ABS was produced by emulsion grafting of styrene-acrylonitrile copolymers onto polybutadiene latex particles. This method continues to be the basis for a considerable volume of ABS manufacture. More recently, ABS has also been produced by continuous mass and mass-suspension processes (237). The various products may be mechanically blended for optimizing properties and cost. Brittle SAN, toughened by SAN-grafted ethylene—propylene and acrylate mbbets, is used in outdoor apphcations. Flame retardancy of ABS is improved by chlorinated PE and other flame-retarding additives (237). 

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