PP-g-PMMA

The free radical polymerized functional polymers with controllable molecular weight are therefore chemically bonded to the side chains of polyolefin (II). One example of PP-g-PMMA [12,13] is shown in Table 1. 

The metallocene catalyst with cationic nature and spatially opened active site provides favorable condition for the incorporation of p-alkylstyrene (p-ms) to polyolefins. The p-ms groups can be easily metallated to produce "stable" polymeric anions for graft-from polymerization. With the coexist of anion-polymerizable monomers, we have prepared many graft copolymers, such as PE-g-PS, PE-g-PMMA, PE-g-PAN, PP-g-PS, PP-g-PB, PP-g-PI and PP-g-PMMA. 

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]. 

Fig. 14 Plot of a flexural modulus and b flexural strength versus content of polar segment ( PP-g-PMMA, PP-g-PS, PP-g-PnBA, PP-g-OH, PP-g-OH/PMMA (7/3) Blend)...

The copolymerization of propylene with allyldimethylsilane (ADMS) was carried out with Ziegler-Natta catalyst systems supported on MgC. The obtained PP-g-ADMS was treated with SOCI2 to produce PP-g-Cl, which works as a macroinitiator for ATRP. PP-g-PMMA (Mn = 67 700, Mw/Mn = 5.3, PMMA segment 79.6 wt%) was produced from PP-Si-Cl with MMA and CuCl/PMDETA [77],... 

As mentioned, polymer hybrids based on POs are effective as a compati-bilizer between the olefinic materials and polar ones. Furthermore, some polymer hybrids, such as PP-g-PMMA, etc., show good mechanical strength as polymer materials. On the other hand, surface modification of the molded polymer is one of the most attractive methods to let polyolefin materials functionalize. In this sense, surface polymerization of functional monomers on polyolefins is an important subject for polyolefin hybrids. As previously referred to, the growth of PS on PP via the RAFT process has been reported [92]. 

In this article, we prepared PP-g-PMMA graft copolymers with different polymer stmctures through a controlled radical polymerization with a PP macroiititiator derived from the hydroxylated PP. In addition, we have confirmed that the thus-obtained graft copolymer worked as a compatibilizer for PP/PLA polymer blends and herein discuss the effect of PP-g-PMMA on the mechanical properties of the PP/PLA polymer blends. 

Entry PP/PLA/ PP-g-PMMA (weight ratio) Tensile Strength (MPa) Young s Modulus (MPa) Elongation at Break (%)... 

Figure 5. Effect of the weight fraction of PLA on (a) the tensile strength and (b) the Young s modulus of the PP/PLA binary blend (triangles) and the PP/PLA/PP-g-PMMA ternary blend (squares).

Figure 7. Morphologies of PP/PLA (40/60) polymer blend observed by (a) optical microscopy or (b) TEM and (c) PP/PLA/PP-g-PMMA (40/60/5) polymer...

One of the most promising applications of polyolefin hybrids is a compatibilizer for blend polymer for polyolefin and non-polyolefin. In Figure 7, TEM micrographs of PP/PMMA and EBR/poly(lactic acid) (PLA) blend polymers with and without polyolefin hybrids as a compatibilizer are displayed. Figure 7(a) represents the phase stracture of a PP/PMMA (62/38 wt%) blend polymer. Since PP and PMMA are immiscible, huge PMMA domains (> 20 pm) exist in the PP matrix. When 5 wt% of PP-g-PMMA (PMMA contents 38 wt%) was added to this blend polymer as a compatibilizer, PMMA domains were finely dispersed as is shown in Figure 7(b). As a result, the physical properties for both FM and FS were drastically enhanced from 35.3 MPa for FS and 1800 MPa for FM to 61.4 MPa for FS and 2200 MPa for FM, respectively. 

Figure 7. TEM Micrographs of (a) PP/PMMA (Weight ratio 68/32) (b) PP/PMMA/PP-g-PMMA (Weight ratio 68/32/5) (c) PLA/EBR (Weight ratio 85/15) (d) PLA/EBR/PE-b-PMMA (Weight ratio 85/15/5)...

PP-g-PCL Polypropylene-gra/t-polycaprolactone PP-g-PMMA Polypropylene-gra/t-poly(methyl methacrylate)... 

Chung TC, Jiang GJ, Rhubright D (1993) Synthesis of PP-g-PMMA copolymers by Borane approach. Macromolecules 26 3467... 

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