Carboxy-telechelic polystyrenes with degrees of polymerization of ca. 70 were examined by small-angle neutron scattering in the Na+ ionomer and methyl ester forms to ascertain the effect of ionic aggregation on the chain dimensions. The ionomers contain ionic aggregates, as demonstrated by smallangle X-ray scattering. The chain dimensions were found to be identical for the ionomer and ester, in agreement with the predictions of Squires et al. but in disagreement with the theories of Foreman and Dreyfus. Detailed analysis of the data showed that the contacts between the two isotopic types were random, as intended. The data were satisfactorily described by a polydisperse assembly of wormlike chains, with a Kuhn statistical length comparable to that for homopolystyrene.

Benzyllithium (BzLi) and 1,1-diphenylhexyllithium (DPHLi) were used to inititate the anionic polymerization of methyl methacrylate (MMA) in the presence of N,N,N',N'-tetramethy\eth.ylenediamine (TMEDA) in THF at -78 and -40 °C. PMMAs with predetermined molecular weights and narrow polydispersities could be obtained with benzyllithium initiator at -78 °C in THF in the absence of TMEDA. Interestingly, even at -40 °C, DPHLi in conjunction with TMEDA was able to provide PMMAs with control on molecular weight and polydispersity values of less than 1.2. The results are explained on the basis of the solvation of the Li+ cation by TMEDA resulting in the stabilization of the propagating enolate anion.

A low-field, 60 MHz, 1H NMR spectrometer yields quantitatively comparable results to 400 MHz spectrometers for the compositional analysis of multicomponent polymer systems.

Metal-free anionic polymerizations of alkyl (meth)acrylates using tetrabutylammonium salts of diethylphenylmalonate, fluorene, and 9-ethylfluorene as initiators were performed in THF at 30 °C. A poor control of molecular weights, inconsistent initiator efficiencies, and broad or bimodal molecular weight distributions were obtained. The effect of counterion nature was studied from the polymerization of methyl methacrylate using the 1,1-diphenylhexyl anion with tetrabutylammonium, tetramethyldiethylguanidinium, and lithium as counterions under otherwise identical conditions. Metal-free initiators resulted in incomplete initiation which is attributed to the fact that the initiation is an equilibrium reaction. In conjunction with possible side reactions such as Hofmann elimination and transfer reactions, this leads to broad and bimodal molecular weight distributions of the resulting polymers.