Branching in high conversion poly(methyl methacrylate)

Abstract

The dilute solution properties (intrinsic viscosity, weight‐average molecular weight, and mean square radius of gyration) of fractions of high conversion, free‐radically initiated poly(methyl methacrylate) samples indicate a slight amount of branching in these samples, consistent with the chain transfer constant with polymer (exclusive of endgroups), Cp = 2.2 ± 0.7 × 10−5, found by Schulz and co‐workers. The dilute solution properties of these fractions are compared with those of fractions of low conversion poly(methyl methacrylate) of comparable molecular weight and with the dilute solution properties of fractions of deliberately branched sample, also of comparable molecular weight. Some evidence was obtained which indicated that impurities in the monomer used for polymerization can lead to additional branching sites in the polymer chains.

Grafting efficiency of atactic polypropylene

“…Some elementary constants of partial polymerization reactions and the degree of branching are usually determined from this dependence. [1][2][3][4] It is not easy to determine at present the average number and weight degree of polymerization of grafted copolymers, and therefore an analogous study of the branching by grafting is difficult to be realized. However we shall point out the other possibility of estimat'ing the branching during grafting by determination of t,he graft,ing efficiency of the basic polymer.…”

The Elimination of Liquid Junction Potentials With the Glass Electrode

“…(1) Equation 1 was previously obtained for these isotactic fractions in acetone solution. 1 The acetonitrile used for all our work was distilled through a packed column and a center cut of constant boiling point was collected in each distillation. The w25d of these center cuts ranged from 1.34142 to 1.34147.…”