Polymerization of vinyl stearate by high energy electrons

Abstract

Vinyl stearate has been polymerized by 1000 kv. electrons with field intensities ranging from 1.0 × 103 to 20 × 103 rep per second; the polymers are considered to be branched. A discontinuity of reaction rate and molecular weight with respect to temperature was noted in the vicinity of monomer melting point, and it is suggested that in this temperature region, the diffusion constant for propagation is easily affected. A linear relationship between field intensity and polymerization rate, and a constancy in molecular weight with varying field intensities, at constant total dose, indicated that polymerization occurs in “volume elements.”

Percolative Transport and Cluster Diffusion Near and Below the Percolation Threshold of a Porous Polymeric Matrix

“…Table V oligomer than a high molecular weight polymer. These results are consistent with characterization studies conducted by other researchers (32,45).…”

“…The values of the Mark-Houwink coefficients depend upon the nature of the polymer, the nature of the solvent, and the temperature. Based on the results of Burlant and Adicoff, the relationship between intrinsic viscosity and molecular weight was observed to be linear between 1,250 and 5,300 Da using these coefficients for poly(vinyl stearate) in benzene (32).…”

Solid-state polymerization induced by radiation

“…Related measurements have also been made by Okamura, Hayashi and Nishii (1962 a) under different conditions of polymerization. Hayashi, Nishii and Okamura (1964 a) observed that, with radiation, the polymer crystals are twinned and a full analysis has been carried out by Carazzola et al (1963). Twinning is also reported in the identical polymer formed from tetroxane at 60"c but not at lOO"c, so that this is not an essential consequence of the crystal geometry, unless this is significantly affected by temperature.…”

“…Trioxane has a hexagonal lattice, with a = 9.26 A and c = 8.60 A, and most reports (Sauter 1932, 1933, Moerman 1937, Okamura, Higashimura and Takeda 1962, Jamison and Noether 1963 give for polyoxymethylene a hexagonal unit cell with a = 4.46 A, c = 17-3 A ; the polymer forms a helix, with 9 monomer units per 5 turns. Carazzola et al (1963) summarize other polyoxymethylene modifications : a stretched fibre with a = 4.470 A, c = 56.00 A and 29 monomers per 16 turns, and an orthorhombic variant with a = 4.76 A, b = 7.66 A, c = 3.563 A and two monomers per unit cell.…”

“…T h e polymerization of vinyl stearate has been investigated by Restaino et al (1956), , Burlant and Adicoff (1958) and nilorawetz (1964). There is a discontinuity in polymerization rate at the melting point, the higher yield in the solid being ascribed to a lower termination rate, arising from limited diffusion.…”