PMMA-g-EPR

Kaneko et al. have reported the preparation of EPR macromonomers, which is useful to synthesize PMMA-g-EPR graft copolymers [106]. Graft copolymers possessing a poly(methacrylate) backbone and EPR branches were successfully synthesized by the copolymerization of EPR macromonomers with MMA. Methacryloyl terminated EPR, which were EPR macromonomers, were prepared by the sequential end functionalization of EPRs with vinylidene end group via hydroalumination, oxidation, and esterification (Fig. 20). The ATRP method can be used for the copolymeriza-... 

Furthermore, by using the ATRP method with a tetrafunctional initiator, the star copolymers consisting of four PMMA-g-EPR graft copolymer arms were also synthesized (Fig. 22). These unique topologies of the obtained copolymers can be confirmed by GPC measurement and NMR analysis. From TEM observation, the morphologies of these graft and star copolymers were remarkably altered by changing EPR branch number and the structure of the... 

Fig. 23 TEM images of a PMMA-g-EPR graft copolymer (EPR content 8.6 wt%), b PMMA-g-EPR graft copolymer (EPR content 38.1 wt%), c four-arms (PMMA-g-EPR) star copolymer (EPR content 36.3 wt %)...

PMMA backbone, which can control the segmental dispersion of PMMA and EPR segments in the range from 1 nm to 100 nm (Fig. 23). Moreover, it was clearly demonstrated that the PMMA-g-EPR graft copolymer with 38.1 wt% of EPR content worked efficiently as a compatibilizer for an EPR/PMMA polymer blend (Fig. 24). DSC analysis revealed the effect of the EPR branch on the Tg value of the PMMA backbone and a little incorporation of an EPR branch caused a large deviation of the Tg value from the homo-PMMA. 

Fig. 24 TEM images of EPR/PMMA blend samples a before adding PMMA-g-EPR graft copolymer (EPR/PMMA = 5/5 wt ratio) and b after adding PMMA-g-EPR graft copolymer (EPR/PMMA-g-EPR/PMMA = 45/10/45 wt ratio)...

On the other hand, the PMMA-g-EPR graft copolymers using the FRP method with AIBN showed a different morphology and thermal property from those after using the ATRP method, leading to the fact that the ATRP method is preferable compared to FRP method for the purpose of preparing well-defined macromolecular structures. Poly(EPR) can also be prepared by the free radical polymerization with AIBN [107]. 

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]. 

In this section, the future developments will be discussed that might be expected in commercial polymer blends comprising at least one of the constituents from the class of commodity polymers. Generally, the commodity polymers considered include polyethylene (and variants LDPE, HOPE, LLDPE, VLDPE and ethylene copolymers), polypropylene (PP), ethylene-propylene rubber (EPR and EPDM), polyvinylchloride (PVC), polystyrene (PS), ABS, and poly(methyl methacrylate) (PMMA). Elastomeric polymers commonly used in tire and associated applications are important in polymer blends as many tire component constructions employ polymer blends to maximize performance. However, these will not be considered here. Thermosetting polymers which could be classified as commodity polymers (urethane, phenolics, epoxies) will also not be covered, but will be mentioned in a later section discussing new polymer blends designed for specific applications (e.g., water based coatings). 

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