SynopsisDetermination of crystallinity of ethylene-vinyl acetate copolymers according to the usual x-ray diffraction method employed for polyethylene is very much hampered by the fact that these copolymers are usually largely amorphous and the Bragg reflections in their daraction diagrams which are therefore broad and weak are drowned by the strong and dominant amorphous halo. As a consequence it is virtually impossible to carry out a realistic resolution of the total diffraction diagram into the individual Bragg reflections in the halo. In the method described in this paper this difficulty is successfully surmounted by taking advantage of the unique shape and placement of the amorphous halo with respect to the Bragg reflections in the diffraction diagrams of these copolymers. This rather fortunate situation permits a direct determination of amorphous content without having to take recourse to the cumbersome resolution of the Bragg reflections and hence one can obtain crystallity indirectly.

Cation initiated polymerizations of various monomers were carried out in the presence of several polystyrene derivatives in an effort to obtain graft copolymers. No success was achieved in grafting with vinyl butyl ether, vinyl ethyl ether, isobutylene, N‐vinylpyrrolidone, or pinene under the particular experimental conditions employed. In the experiments involving vinyl n‐butyl ether, the presence of the various polystyrenes appeared to have no effect on the polymerization of this monomer or on the DP of the polyvinylbutyl ethers obtained. However, when styrene was polymerized in the presence of poly‐p‐methoxystyrene (PPMS), graft copolymer was readily obtained. The success of this reaction demonstrates the feasibility of preparing graft copolymers by an ionic mechanism and yields additional proof of an ionic chain transfer reaction with aromatic species in which the latter are incorporated into the chain. Data obtained on the styrene‐PPMS system are discussed in terms of a simple kinetic scheme. The molecular termination constant of PPMS was found to be only 1/67th of that of p‐methylanisole, a low molecular weight analogue. The low chain transfer effectiveness of PPMS is believed to be due to constraints placed on the availability of the transfer sites which are linked in a polymeric chain.

The development of a fractional crystallization technique for characterization of polypropylenes with respect to stereoregularity is described. It is a simple technique which is attractive for routine analysis and under suitable conditions yields quantitative data with good reproducibility. Separation by fractional crystallization from hot xylene solution is shown to take place according to polymer crystallizability and is relatively independent of molecular weight. It thus represents an alternative and in some ways superior approach to the more commonly used fractional extraction method. Preliminary work indicates that the fractional crystallization method may prove of value in establishing correlations between the stereoregular nature of polypropylenes and their physical properties.

An improved preparation and handling procedure for the monomer is described. The polymer was prepared best by emulsion polymerization, although anionic polymerization was also found to be operable. A number of properties of the polymer are described, including solubility, the infrared absorption spectrum, x‐ray diffusion (amorphous scattering), dielectric constant (2.56 ± 0.05), and dielectric loss tangent (0.0006 to 0.0035 over the range 102 to 1011 c.p.s.). Copolymerization with trifluorochloroethylene gave a copolymer containing 0.096 mole fraction of trifluorochloroethylene, and with styrene a copolymer containing 0.397 mole fraction. The copolymerization curve and constants for copolymerization with styrene are presented and discussed.

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