Polymer-reactive antioxidant with rubbers

Reactions of Reactive Antioxidants with Polymers by Normal Chemical Procedures. Grafting of vinyl antioxidants e.g., VI, into rubbers has been used to produce modified rubber latices (26). Even simple... 

Another polymer reactive antioxidant which can be combined with rubber during vulcanization involves the 1,3 addition reaction of nitrones to the double bond in rubbers, reaction 4 (11). 

Reactivity With Nitroso Compounds. Functionalization of diene based rubbers with aromatic nitroso compounds bearing aminic or phenolic moieties 174, like with iV,A-diethyl-4-nitrosoaniline, 4-nitrosodiphenylamine, 4-nitrosodiphenylhy-droxylamine or 4-nitrosophenol represents an effective way for the synthesis of polymer-bound antioxidants [233], The respective nitroso compound can be mixed with rubbers during compounding or with concentrated rubber latexes. The chemical attachement of stabilizing active moieties takes place during subsequent... 

It is concluded that the modification of rubbers after manufacture with chemically reactive antioxidants offers the most promising procedure for producing concentrates of polymer-bound antioxidants that can be used as conventional additives. 

Reactions of Antioxidants with Preformed Functional Groups. The reactive chlorine in epichlorohydrin polymers is a specific though typical example of this approach (11). A more general reaction is the epoxidation of the double bonds in rubbers and subsequent reaction of the epoxide group with an amine antioxidant (reaction 1)... 

Reaction of conventional antioxidants with functionalised polymers. Many unsaturated rubbers can be made reactive toward conventional antioxidants by chemical modification. W ys in which this can be... 

The ozone concentration in the troposphere during the daytime is typically about 1 pphm (parts per hundred million parts of air by volume) [20], Values up to 100 pphm were measured in some photochemical smog areas. The molecular mechanism of the ozone aging of diene based elastomers was studied in detail and is well understood [19,21], Products or intermediates different from those arising in autoxidation or photo-oxidation of polymers were identified ozonides (3), zwitterions (4), diperoxides (5), polyperoxides (6), polymeric ozonides (7) and terminal aldehydes (8). Reactivity of aminic antiozonants (AOZ) with these species accounts for the protection of rubbers against atmospheric 03. AOZ must also possess antioxidant properties, because the free radical processes are concerted with ozonation due to the permanent presence of oxygen. 

The antioxidant and reactive properties of fullerene make it suitable for use in rubbers, especially those exposed to UV lights as they become stronger and more elastic. Aging does not decrease mechanical properties of rubber and improves resistance to thermal degradation [77-80]. Filling the polymer with small amounts of fullerene could lead to a new set of properties that have specific advantages over those of rubbers currently in use. 

Adhesives are polymers that are initially liquid but solidify with time to give a joint between two surfaces [12,13]. The transformation of fluid to solid can be obtained either by evaporation of solvent from the polymer solution (or dispersion) or by curing a liquid polymer into a network. Table 2.3 lists some common adhesives, which have been classified as nonreactive and reactive systems. In the former, the usual composition is a suitable quick-drying solvent consisting of a polymer, tackifiers, and an antioxidant. Tackifiers are generally low-molecular-weight, nonvolatile materials that increase the tackiness of the adhesive. Some tackifiers commonly used are unmodified pine oils, rosin and its derivatives, and hydrocarbon derivatives of petroleum (petroleum resins). Several polymers have their own natural tack (as in natural rubber), in which case additional tackifiers arc not needed. 

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