Compatibilizing action

All structural determinations confirm the compatibilization action of the functionalized MA-g-SEBS. A possible mechanism is reported in Figure 7. The PET-MA-g-SEBS copol3oners formed during processing act as a bridge between the two phases improving adhesion of the two polymers and the properties of the blend. 

Table 1 lists polyethylene blend systems for which commercially available materials have been reported as providing a compatibilizing action. Note that the list of suppliers is indicative, and similar polymers may be available from alternative sources. In most cases the compatibilizing effect reported included establishment of a stable, fine morphology and achievement of improved impact or ultimate extensional properties compared to the un-compatibilized blend. The systems are discussed briefly below, where mention is also made of non-commercial systems described in the technical literature. Readers who wish to investigate further the systems described here are directed to Boimer and Hope (1993), which contains a comprehensive bibliography. 

However, in order to postulate a compatibilizing action, one must observe a remarkable broadening of the maxima of relaxation or two relaxation maxima eroding into one maximum. Such effects are much more pronounced for filled interpenetrating polymer networks (see 7.5 ). 

A variety of other third polymers may be added to incompatible polyblends to improve compatibility. Most of them are random eopolymer structures with flexible or rubbery properties. Their compatibilizing action may be visualized in three ways ... 

Table 18 Some features of the compatibilizer action on the formation and properties of IPNs based on PU-PBMA [341]...

Els and McGill [48] reported the action of maleic anhydride on polypropylene-polyisoprene blends. A graft copolymer was found in situ through the modifier, which later enhanced the overall performance of the blend. Scott and Macosko [49] studied the reactive and nonreactive compatibilization of nylon-ethylene-propylene rubber blends. The nonreactive polyamide-ethylene propylene blends showed poor interfacial adhesion between the phases. The reactive polyamide-ethylene propylene-maleic anhydride modified blends showed excellent adhesion and much smaller dispersed phase domain size. 

Tang et al.84,85 also examined the incorporation of MMT in intumescent PP with a compatibilizer (hexadecyltrimethylammonium bromide) which is usually used as surfactant for making OMMT. Evidence of making a nanocomposite is shown with and without the intumescent system. Cone calorimetry shows a large improvement in the flammability properties when using OMMT. The results are similar to what we showed above. They postulated a mechanism of action suggesting the formation of an aluminophosphate structure but no evidence was given. 

As schematically own in Fig. 30, the cell membranes of living organism (/ S6) are composed of a lipid bilayer and form the interface between the intracellular and the extracellular aqueous parts. Concentrations of metal ions and amino adds in the cell are thus kept constant and the biological functions in the cell are executed. Specifically, the concentration of metal ions is in a dynamic equilibrium between the inside and the outside of the cell membrane, and it has been suggested that the mass tran rt through the membrane is mediated by lipoproteins. For the metal-km tran rt through the membrane, the participation of a group of cyclic conqxrunds called lonophores is important, which is dosely related to the antibiotic actions of cyclic peptides and cyclic depsipeptides (iJ6). These cyclic compounds are compatibile... 

REMOL ASN liquid has an excellent dispersing and compatibil-izing action in one-bath dyeing of wool or polyamide blends with acrylic fibers using anionic and cationic dyes and in dyeing polyester/acrylic fibers with disperse and cationic dyes. 

Numerous compatibilizers can be produced by grafting monomers (containing some kind of functional groups) in melt onto homopolymers and copolymers of olefins or their blends (25). Reactive extrusion (26) is a basic process for this when the twin-screw extruder is used as a reactor of continuous action (27). 

In some cases, lack of noticeable influence of electron beam radiation on the values of tensile and Charpy impact strengths of 24-23-21-15-17 LDPE-HDPE-PP-PS-PET blends (based on recycled polymers) compatibilized with 1% trimethylol propane trimethylacrylate (TMPTMA) were found. Zenkiewicz et al. ° explained this lack of influence by the protective action of aromatic rings of PS and PET that hindered cross-linking. In the same article, the addition of 10% of styrene-ethylene/butylene-styrene elastomer grafted with maleic anhydride (SEBS-g-MA) led to the great increase of both tensile and Charpy impact strengths. 

The addition of a polypropylene grafted maleic anhydride (PP-g-MA) compatibilizer into polypropylene-co-ethylene/polybutylene succinate blends and the subsequent irradiation allowed prevention of degradation mechanisms leading to mechanical stability. The cyclic anhydride group of the PP-g-MA first permitted compatibilizion of both polypropylene-co-ethylene and polybutylene succinate and a second action as an "energy sink."... 

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