Stereoregularity of polymethacrylonitrile

The NMR of Polymers

“…Analogously, samples of polymers of methacrylic anhydride [368,480,689], a polymer of methacrylonitrile [658,659], a polymer of the menthyl ester of methacrylic acid [657], and also polymers of the dihydrate of barium methacrylate [74] were converted into polymethyl methacrylate by hydrolysis and methylation since the method of determining stereoregularity from the NMR spectrum has been developed best for polymethyl methacrylate.…”

Solid-state polymerization induced by radiation

“…The methyl group allows the formation of regular (isotactic, syndiotactic) or random (atactic) polymer. From nuclear magnetic resonance results (Sobue, Uryu, Matsuzaki and Tabata 1963) it is deduced that polymer formed by ionic catalysis of monomer solution in toluene contains 32% of isotactic and 13% of syndiotactic material, whereas gamma radiation of the solid monomer at -78"c gives 36% of isotactic, but no syndiotactic material although this is the configuration of lower energy. T h e arrangement of successive monomer units in the radiation-induced material can be represented by D D D L L L D D D L L L but no attempt has been made to relate this polymer structure to the arrangement of monomers with the unit cell.…”

“…T h e influence of the lattice does not appear to prevail in the case of acrylic acid of which the x-ray structure (Chatani et al 1963) and electron spin resonance pattern (Shioji et al 1963) Differences have been reported in the arrangement of other units along the polymer chains depending on whether they originate in the solid or the liquid. Acetylene polymerized from solid monomer is richer in trans linkages (Tabata, Saito, Shibano and Oshima 1962) ; solid-state polymerization of methacrylonitrile shows an absence of syndiotactic (alternating) sequence (Sobue, Uryu, Matsuzaki and Tabata 1963). Differences in polymer structure are also reported as between n butyl isocyanate, irradiated in the solid or liquid state .…”

Stereospecific polymerization of methacrylonitrile

“…Stereospecific polymerization of polar monomers has been widely investigated and some of the attempts have been successful (1). Preparation of stereoregular polymethacrylonitrile (PMAN) was also attempted by Sobue et al (2) using butyllithium or y-rays at low temperatures, but neither the x-ray diffraction pattern of the polymers nor the NMR spectra of polymer solutions in acetone gave any indication of the stereoregularity of the polymer. Quite recently, Natta et al (3) have studied the stereospecific polymerization of a-alkylacrylonitrile by several organometallic catalysts and found that organomagnesium compounds, such a s diethylmagnesium, have high catalytic activity for stereospecific polymerization.…”