Synthetic resins

The October 1956 issure of Modern Plastics(l5) contains an excellent review of the various classes of synthetic resins together with their electrical and physical properties. The groups: phenol formaldehyde, urea formaldehyde, furfural formaldehyde, cellulose acetate, cellulose nitrate, ethyl cellulose, vinyl resins, casein, acrylic, cumarone, polystyrene and synthetic rubber are discussed at considerable length. The methods of manufacture are briefly explained. Their uses and properties are more completely described. The table of properties checked by the Bureau of Standards is the most complete and accurate the writer has seen. Properties which are included and are of especial interest to the electrical engineer are water absorption, heat resistance, breakdown voltage, dielectric constant, power factor, and softening point. Many other physical, chemical, and mechanical properties are given. The aniline formaldehyde and phthalic anhydride groups are not mentioned.