Maleic anhydride graft polyolefins

Interchain copolymer formation Copolymers of reactive polystyrene and polymers with amide, mercaptan, epoxy, hydroxy, anhydride or carboxylic acid groups, copolymer of polypropylene grafted with maleic anhydride and nylon-6, copolymer of polyolefines and polystyrene, copolymer of EVA grafted with methacrylates and grafted polystyrene... 

If chemical reaction can take place between the functional groups on the compatibilizer and the two phases, then this will result in high interfacial adhesion and the miscibility is important only insofar as the reacting groups need to approach one another in order to enable reaction. Often this functionalization is achieved in a separate reactive-processing step, such as the grafting of maleic anhydride to polyolefins. Scheme 1.48 (Moad, 1999). 

Free radical grafting of maleic anhydride (MA) onto polyolefins has gained wide industrial use. MA modified polyolefins are an essential part of many plastics formulations. They are used as chemical coupling agents, impact modifiers, and compatibilisers for blends and filler reinforced systems [65-67]. 

Several problems can be defined that are typical for grafting by reactive extrusion. Difficulties encountered in developing a commercial process for the grafting of maleic anhydride on polyolefines by reactive extrusion are summarized below (1). 

Grafting of maleic anhydride on polyolefines is generally performed to improve the adhesion to metals, glass fibers, or other polymers. The first... 

One of the most popular processes in reactive compa-tibilization is the grafting of maleic anhydride (MAH) onto polyolefins, to make them more reactive in the blending process [81-83]. For example, heating LDPE, PP, or EPR with peroxide produced free radicals which added easily across the double bond of MAH, thus making the polyolefins easily reactive with nylons, polyesters, and other second polymers in polyblends. 

In the present paper, we report on the compatibilization of clay with polyolefins, specifically low and high density poly-ethylenes (LDPE, HDPE), through the radical-induced polymerization of maleic anhydride (MAH) in the presence of the polymer and clay, so that the MAH is grafted on the PE and the anhydride groups concurrently react with the filler surface (l, 2). 

In addition, borane-containing POs can be prepared by copolymerization of olefin with borane monomers or by hydroboration of polyolefins including unsaturated groups, such as olefin-divinylbenzene copolymer and olefin-diene copolymers. Many kinds of graft copolymers, such as poly-elhylene-gra/f-poly( vinyl alcohol), PE-g-PMMA, polypropylcnc-gra/f-poly-(maleicanhydride-co-styrene), polypropylene-gra/f-poly(methacrylic acid), polypropylene-gra/f-poly(vinyl alcohol), polypropylene-gra/f-polycaprolac-tone (PP-g-PCL), polypropylcnc-gra/f-poly(methyl methacrylate) (PP-g-PMMA), poly( ethylene-co-propylene)-gra/f-poly(methyl methacrylate) (EPR-g-PMMA), and poly(ethylene-co-propylene)-gra/f-poly(maleic anhydride-costyrene), have been synthesized by such a method resulting in controllable composition and molecular microstructures [63-66]. 

Graft reactions and functionalization reactions Graft copolymer of polystyrene and maleic anhydride graft copolymer of polyolefines and vinylsilanes graft copolymers of polyolefines and (meth)acrylic monomers, graft copolymer of EVA with acrylic acid graft copolymer of polyolefines and maleic anhydride halogenation of polyolefines or EVA... 

Some authors combined the IPN concept with the use of compatibi-lizers similar to that mentioned in Section 2. These may be a coupling agent such as epoxy-functionalized polysiloxane, polysiloxane copolymers or an organofunctional grafted polyolefin such as poly(ethylene-co-methacrylate) or MA-g-EPDM (maleic anhydride grafted EPDM) [124,125, 133]. Knaub et al. [150] studied a poly(urethane-ureas)/PDMS semi-IPN in... 

The third advantage associated with metallocene catalysts is that the predominant mechanism for chain termination is by /3-hydride elimination. This produces a vinyl double bond at the end of each polymer chain. Further functionalization of the vinyl group by graft polymerization with maleic anhydride and other functional monomers is far more effective than is typical for polyolefins obtained by conventional catalysts. 

Examples of acid modified polyolefins are the copolymers of ethylene with acrylic acid or methacrylic acid. Variations include the partially neutralised acid copolymers with metal ions (ionomers) or terpolymers of ethylene, an acid and an acrylate such as methyl acrylate or isobutyl acrylate. Acid-containing extrudable adhesives are widely used to bond to aluminium foil. Examples of anhydride-modified polyolefins include terpolymers of ethylene, maleic anhydride and acrylates such as ethyl acrylate or butyl acrylate and the anhydride-grafted polyolefins. Some typical applications and stmctures of a variety of multilayer materials with extruded polymer tie-layer adhesives, as described in Du-Pont trade literature, are detailed in Table 16.2. 

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