Two methods for controlling the working time of an addition-type silicone impression material are presented. The progress of the polymerization reaction of this modified system was studied using viscosity and a new "compression set" technique. The physical properties are presented and compared to those typical of condensation silicones, and a method of clinical use is suggested.

The first reference to the use of silicones in cosmetics found by the author was an article published in 1953 [Ref 1]. Further articles rapidly followed as dermatologists evaluated the properties of this new class of materials as protective agents. The first paper to appear in the Journal of the Society of Cosmetic Chemists was in 1955 [Ref 2], which described methods to evaluate the relative c...

During the last few years the use of fluorochemicals to provide stain repellency and/or stain release properties to apparel goods has rapidly grown. The use of fluorochemicals as well as durable press resins, however, has a detrimental effect on the fabric softness. Providing premium softness is key to satisfy the highly demanding aesthetic requirements of many of today’s apparel products. Alth...

Contributors: D. G. Bolitho, Lexie Friend, L. M. Milligan and Janice Parker.

Hemagglutinating Behavior of Mouse and Eggadapted Type A (PR8) Influenza Virus: Seymour S. Kalter .............. ........................ 184 Cytological Evidence Opposing the Theory of Brachymeiosis in the Ascomycetes: Lindsay S. Olive ........... ........................... 185 Inability of Thymine and Adenine to Substitute for Pteroylglutamie Acid in the Folic Acidd4eflient Rat: H. G. Peteri...

Silicones are an important class of hydrophobic compounds in widespread use. To evaluate their fate in the environment, an accurate value of the air-water partition (Henry's law) constant is necessary, which, unfortunately, is lacking at present. A static head space and a newly developed dynamic vapor entry loop method were used to obtain the air-water partition constant for six volatile methyl...

A range of silicone rubbers were created based on existing commercially available materials. These silicones were designed to be visually different from one another and have distinct material properties, in particular, ultimate tensile strengths and tear strengths. In total, eleven silicone rubbers were manufactured, with the materials designed to have a range of increasing tensile strengths fr...