No abstract

The various proposed structures for polymers derived from benzyl type compounds have been discussed and the likelihood of these structures considered in the light of a study of their preparation and properties. Both the para substituted structure of Shriner and Berger and the pendant structure of Henne and Leicester were rejected chiefly on the basis of physical properties, degradation behavior, and x‐ray and infrared evidence. Flory's randomly branched structure also fails to account for the degradation behavior and the infrared spectrum. A new configuration which is a nonrandomly substituted, highly branched molecule is advanced. This structure contains predominantly two types of benzene rings, i.e., a relatively small number of highly substituted rings and a considerably larger number of monosubstituted benzenes existing in the form of pendant benzyl groups.

The preparation of poly‐p‐xylylene, , in 24–26% yield, by pyrolysis of p‐xylene, is described in detail. The nature and amount of by‐products of the pyrolysis were determined. The physical appearance and the following properties and reactions of the polymer are described: x‐ray diffraction, crystallinity, optical constants, infrared absorption spectrum, degradation by autoxidation in solvents and by pyrolysis, dielectric constant and loss, sulfonation and chlorination. The significance of this data is discussed relative to an understanding of the mode of formation and the structure of the polymer.

No abstract

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.