Graft polymers with macromonomers. II. Copolymerization kinetics of methacrylate‐terminated polystyrene and predicted graft copolymer structures

Abstract

SynopsisCopolymerization studies of methacrylate-terminated polystyrene macromonomers (MI) with several comonomers (M,) verified the modified kinetic scheme and permitted prediction of graft polymer compositions and structures. Instantaneous and cumulative copolymer compositions, average graft distributions, and grafts per molecule are predicted from FORTRAN IV or BASIC programs. The r, relative reactivity ratios determined from styrene copolymerization (0.61) or from low conversion acrylic monomer in aqueous suspension (4.4) had good agreement with literature values (about 0.6 and 0.4, respectively). Decreased macromonomer reactivity determined at high acrylic monomer conversions was attributed to phase separation phenomena. The Macromers also exhibited lower reactivity than predicted when copolymerized with acrylic monomers in DMSO/benzene solutions (r2 -0.8).

Strategies for compatibilization of polymer blends

“…[24] The most controlled technique for the synthesis of grafted copolymers relies upon the radical (co)polymerization of so-called macromonomers. [25,26] 3.1.2. Types of compatibilized blends (Table 1) Early efforts were concentrated on blends of (di)block copolymers with homopolymers possessing repeat units identical or chemically similar to each segment of the copolymer.…”

“…The use of grafted copolymers is another possible route for the control of the phase morphology and the mechanical properties of immiscible polymer blends. In addition to polymer-polymer or polymermonomer reactions, a large variety of macromonomers has been prepared as precursors of grafted copolymers [25,26] with some control on the copolymer structure, since the length and number of grafts are dictated by the macromonomer molecular weight, the comonomer feed and the comonomer reactivity ratios. Recently, ω-dihydroxy PS has been synthesized as a macromonomer for the synthesis of poly(PBT-g-styrene).…”

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“…2b). The graft copolymers were synthesized by using the macromonomer technique of Milkovich in a free radical copolymerization in toluene with AIBN as initiator [17], employing polystyrene macromonomers of different molecular weight, synthesized according to the literature [18], and tert-butyl methacrylate (TBMA), followed by hydrolysis to get the methacrylic acid/styrene graft copolymers (PMAA-g-PS, Fig. 2c).…”

Radical Copolymerization Behavior of Macromonomers; Incompatibility Effect

“…Cameron and Chisholm 14 also reported similar results, i.e., the higher the molecular weight, the lower the copolymerization reactivity of the macromonomer, with the copolymerization system of poly-(dimethylsiloxane) macromonomer having a methacrylate end group with styrene and acrylonitrile. On the other hand, Schulz and Milkovich 15 reported the same or slightly lower reactivity of macromonomers compared with the small monomer corresponding to the polymerizable end group in the copolymerization system of methacrylate-terminated polystyrene macromonomers. There are also other reports showing that the copolymerization reactivity of a macromonomer is not so different from that of a small monomer corresponding to the polymerizable end group even with a molecular weight of macromonomer as high as ten thousands.…”