Suspension Grafting Copolymerization of EPM-g-MAN and Its Toughening Effect on SAN Resin

Abstract

EPM-graft-methyl methacrylate and acrylonitrile (EPM-g-MAN) was synthesized by graft copolymerization of methyl methacrylate (MMA) and acrylonitrile (AN) onto ethylene-propylene bipolymer (EPM) using the method of suspension polymerization. A novel engineering plastic with high impact strength, AEMS, which shows excellent resistance to weatherability and yellow discoloration and aging properties, were prepared by blending EPM-g-MAN with styrene-acrylonitrile (SAN) resin. The influence of the suspension grafting copolymerization technologies, including monomer ratios, EPM ratios, initiator content on monomer conversion ratio, grafting ratio, grafting efficiency, and the impact strength of AEMS, were investigated. The result showed that the optimized reaction conditions were obtained when the mass ratio of AN/MMA-AN(f AN ) was 15 wt%, the mass ratio of EPM/(EPM þ MMA-AN) was 60 wt%, and the mass ratio of BPO/(EPM þ MMA-AN) was 0.6 wt%. When the EPM/ AEMS mass ratio was 25 wt%, the notched Izod impact strength of AEMS reached 55.9 kJ/m 2 . DSC and DMA analysis showed that the compatibility of EPM-g-MAN and SAN resin improved when the grafting chain polarity was appropriate. Transmission electron microscopy analysis showed that EPM phase was the near continuous phase in the shape of bead string with diameter of about 0.15 mm and had good compatibility with SAN resin. Scanning electron microscopy analysis indicated that AEMS fracture surface appeared 'root beard' morphology. These phenomena indicated that the toughening mechanism was shear yielding of matrix, which endowed AEMS with remarkable toughness.

Reaction mechanism of suspension graft copolymerization of styrene and acrylonitrile in the presence of ethylene propylene diene terpolymer

“…Gra copolymers, commonly used as compatibilizers in polymer blends, are of particular scientic and industrial interest for ensuring the dispersion of one phase in another by reducing interfacial tension. 1,2 Many synthetic pathways have been used in order to obtain gra copolymers by traditional free radical polymerization, [3][4][5][6][7] due to its signicant advantages like simple operation, mild reaction conditions, and utility with a wide selection of different monomers. Currently, the ethylene propylene diene terpolymer-g-poly(styrene-co-acrylonitrile) (EPDM-g-SAN) is mainly produced in industry using the solution gra copolymerization method.…”

Well-defined poly(methyl methacrylate) grafted to isotactic polypropylene by metal-catalyzed living radical polymerization

“…21,22 Maleic anhydride (MAH)-modified PO (PO-MAH) is well known as a commercially available functionalized PO and many types of PO-MAH with various MAH contents, molecular weights and olefin compositions have been industrially produced. Compared with the direct copolymerization method, this method has the advantage in that it can provide not only ethylenic but also propylenic and higher a-olefinic polymers.…”

“…20 It has been reported that the radical grafting of polar monomers on PO is also an important method for preparing functionalized POs and the incorporation of many kinds of polar monomers, such as methacrylates, acrylates, styrene, and so on. 21,22 Maleic anhydride (MAH)-modified PO (PO-MAH) is well known as a commercially available functionalized PO and many types of PO-MAH with various MAH contents, molecular weights and olefin compositions have been industrially produced. Compared with the direct copolymerization method, this method has the advantage in that it can provide not only ethylenic but also propylenic and higher a-olefinic polymers.…”