The variation of helical pitch in multicomponent mixtures consisting of a solvent and one or more different molecular weight polymeric species can be described by an equation in which the pitch is a quadratic function of the number densities of polymeric chiral solutes and achiral solvent, each of which has characteristic molecular twisting powers. The equation is shown to apply to literature data on the pitch of poly(y-benzyl glutamate) (PBLG) in m-cresol, 1,2,3-trichloropropane, and dioxane and to a large body of new data presented herein on PBLG in chloroform, by using samples of known polydispersity with molecular weights varying from 85 000 to 660 000.

The addition of the chiral solvent, phenethyl alcohol to the cholesteric lyotropic phases of the synthetic polypeptides poly-(y-benzyl-L-glutamate) or poly-(y-benzyl-D-glutamate) (PBLG and PBDG) causes a strong perturbation of the pitch. Both polymers are in the a-helical conformation and, in both cases, I-alcohol increases and &alcohol decreases the pitch relative to the racemic alcohol.

Aniline markedly accelerated polymerization .of methyl methacrylate initiated by metal chelates of ,6-diketones. The kinetic studies of the polymerizaion of methyl methacrylate initiated by Ni (II) acetyl acetonate in the presence of aniline yielded Rp=[IJM~(A)o.611 (MJ1.3 7• The polymerization was of free radical in character. The accelerating effect of aniline was attributed to its reduction activation of the chelate, The activation energy for the overall polymerization was 21.3Kcal/moZe, which yielded 33.4Kcal/mole for the activation energy for the initiation.

The kintetic studies of polymerization of methyl methacrylate initiated with nickel ethyl acetoacetate gave the following . Some aromatic amines such as aniline markedly accelerated the polymerization, while pyridine had no such effe:::t. The activation energy of initiation was 24.8 kcalfmot in the absence of aniline, and 8.8 kcal/mol in the presence of aniline. Both the kinetic data and the infrared spectra of the polymer indicated that the polymerization was radical in nature. The reaction order against monomer varied, as the temperature differed. The spectrophotometric investigation indicated formation of a complex between the chelate and the monomer, or amines. It also showed that the formation of a complex was not a factor which controlled the rate of initiation. A scheme of initiation mechanism was .presented on the basis of the above experimental evidence. InboducHonPolymerization of vinyl compounds initiated by metal chelates of l3-diketones has been studied by a few wcrker.P"? TJ1e function of the chelates has been considered a ttribu ta ble to the formation 145