Monomer M1 Research Articles

Anionic copolymerization of methacrylates

AbstractAn investigation was carried out of the anionic copolymerization of methyl methacrylate (M1), 2‐methoxyethyl methacrylate (M2), and 2‐(N, N‐dimethylamino) ethyl methacrylate (M3) in benzene solution at 20°C initiated with lithium tert‐butoxide. The monomer reactivity ratios (M1–M2) r1 = 1.51 ± 0.05, r2 = 2.10 ± 0.10, (M1–M3) r1 = 1.20 ± 0.10, r3 = 0.40 ± 0.05, (M2–M3) r2 = 1.40 ± 0.15, r3 = 0.60 ± 0.15 show that the reactivities of the individual monomers M1, M2, and M3 do not differ too much from each other. A study of the microstructure of copolymers M1–M2 by the NMR method revealed that at low conversions the tacticity of the copolymers depends on the concentration of 2‐methoxyethyl methacrylate in the starting monomer mixture; in the initial stage of copolymerization it is strongly dependent on conversion. Already a low content of M2 in the starting monomer mixture (below 1%) strongly affects the tacticity of the forming copolymer by depressing the content of the isotactic component.

Polymerization of vinylcyclopropanes. IV. Radical copolymerization of 1,1‐dichloro‐2‐vinylcyclopropane with maleic anhydride

AbstractRadical copolymerization between 1,1‐dichloro‐2‐vinylcyclopropane (M1) and maleic anhydride (M2) was studied. Rearrangement of the radical caused from monomer M1 and cyclization of growing chain, which was suggested from a consideration of composition and structure of the obtained copolymer, complicate the propagation step in this system. A peculiar copolymer composition equation containing four reactivity ratio parameters was developed, and these parameters were determined.

Synthesis, polymerization, and copolymerization of diphenyl‐p‐styrylphosphine, phosphine oxide, and phosphine sulfide

AbstractDiphenyl‐p‐styrylphosphine (I), prepared by the reaction of diphenylchlorophosphine with p‐styrylmagnesium chloride, was converted to the corresponding oxide (II) and sulfide (III) by treatment with tert‐butyl hydroperoxide and sulfur, respectively. These substituted styrenes polymerize readily with thermal or free radical initiation to high molecular weight polymers. These polymers are somewhat more thermally stable than polystyrene. Thus their Ti's in air were in the range 320–365°C. and in nitrogen, 375–395°C. Their T10's were in the 390–415°C. range in air and 425–435°C. in nitrogen. Polystyrene in air has a Ti of 263°C. and a T10 of 340°C. The monomers copolymerize readily with styrene and methyl methacrylate, the low conversion polymers always containing more phosphorus than the monomer mixtures. Reactivity ratios were determined, from which Q and e values were calculated. These values for the following monomer pairs are (phosphorus monomer M2): styrene‐I, r1 0.52, r2 1.43, Q2 1.34, e2 −0.30; styrene‐II, r1 0.42, r2 1.40, Q2 1.34, e2 −0.07; styrene‐III, r1 0.43, r2 1.49, Q2 1.37, e2 −0.13; MMA‐I, r1 0.32, r2 0.91, Q2 1.58, e2 0.80; MMA‐II, r1 0.38, r2 1.46, Q2 1.42, e2 −0.35; MMA‐III, r1 0.29, r2 1.22, Q2 1.58, e2 −0.62. Analysis of these data indicates that these phosphorus moieties are activating through strong electronegative effects. The extent of activation is intermediate in intensity between mildly activating groups (e.g. Cl) and strongly activating groups (e.g. CN or NO2). The behavior of diphenyl‐p‐styrylphosphine is of particular interest in this respect, since its electronegativity points to strong electron delocalization.

The effect of depropagation on copolymer composition. I. General theory for one depropagating monomer

AbstractThe following mechanism is postulated for the copolymerization of α‐methylstyrene (or similar 1,1‐disubstituted ethylene), M2, at temperatures near its ceiling temperature but far below the ceiling temperature of the comonomer, M1. Either M1 or M2 may combine with a polymer chain ending in either m or m. When either monomer adds to a chain ending in m, the new active chain is stable to depropagation, as is a new active chain formed by either monomer adding to a chain ending in m1m. However, whenever either monomer adds to a chain ending in m1(m2), where n ≥ 2, the newly formed active chain will have a finite tendency to depropagate and to “unzip” until the terminal radical is m1(m2), which itself is stable to depropagation. However, a sequence of m1(m2) becomes trapped, or stabilized, if it reacts with a molecule of M1 and then with a molecule of either M1 or M2 before the first unit of monomer M1 can split off. A steady‐state kinetic analysis of this mechanism leads to a copolymer composition equation which, although unwieldy, allows the following general predications. (1) Temperature will have a marked effect on the shape of the copolymer composition curve in the region of the ceiling temperature of M2. (2) Dilution of the monomers by an inert solvent will have a marked effect on the shape of the copolymer composition curve in the region of the ceiling temperature of M2. (3) The limiting mole fraction of M2 in a copolymer prepared at high temperature will be two‐thirds. Two other mechanisms of copolymerization involving the depropagation reaction of one monomer are analyzed to obtain copolymer composition equations. In one of these, it is assumed that M1 will never split off an active chain. This results in the same qualitative predictions as above but slightly different quantitative predictions. In the other case studied, it is assumed that M1 will never split off an active chain and that when a chain ends in m1(m2), it can unzip all the way to m1m. This leads to the same qualitative predictions as before but the limiting mole fraction of M2 in a copolymer prepared at high temperature is one‐half rather than two‐thirds.