The early history of vulcanization and the beneficial changes wrought on rubber by Goodyear's famous process are reviewed. An outline is given of the methods used in vulcanization, the principal facts, and the theoretical considerations of the
The dispersed made of placement of the tables of physical constants and the methods for the characterization of common types of organic compounds is somewhat unconventional. Obviously, unconventional need not mean unsatisfactory.The clarity of the diagrams, the neatness of the tables and the attractive format of the text create a very favorable impression. Only a. few minor typographical errors were noted. Unfortunately, the word, Soxhlet, is misspelled a t least a doeen times, though it is spelled correctly in places.Eaoh teacher and student of organic chemistry has his porsonal opinion as to what constitutes an adequate, practical experience in organic chemistry for the undergraduate chemist. Because of these myriad viewpoints it would seem almost impossible to encompass in s. single volume enough material to satisfy everyone. Dr. Vagel's ambitious and admirable attempt to offer a complete experience in a single volume is noteworthy. He has written a book whiohundouhtedly will have wide appeal. The fist six pspers deal with theoretical physical aspects of phase transformations; the next six are concerned with nonmetals; and the last five with metals. Much of the material represents the reaults of the current researchea of the various authors.Since the audience to which the pspers were addressed consisted of specialists, invited because of their interest in this field, the book as a whole is rather advanced for the general reader. Aside from its value to specialists in the field, it is of interest because it shows how a variety of points of view can be used to illuminate s. particular subject. According to the Foreword, physicists, chemipts, metallurgists, ceramists, and crystallographers were among those who joined in presenting the pspers and participating in thediscussion.
Calendered sheets of pale crepe rubber containing an ultra‐accelerator, piperidinium N‐pentamethylenedithiocarbamate, and zinc oxide were embedded in powdered sulfur and kept at room temperature. Tensile strengths up to 294.2 kg./cm.2 (4185 psi) and elongations up to 530% were attained; the combined sulfur in 115 weeks was 3.60%. Calendered pale crepe rubber containing 10 parts of yellow mercuric oxide to 100 parts of rubber allowed to stand covered with quinone dioxime (GMF) powder at room temperature slowly vulcanizes, reaching a tensile strength of 53.1 kg./cm.2 (754 psi) in 405 days, and retaining this condition for at least twice this same period of time. The elongation reached 740%, and the set was 0.16. The tensile strength obtained is almost as high as that obtained in a press cure with quinone dioxime alone. The untreated sample containing yellow mercuric oxide alone showed a tensile strength of only 5.3 kg./cm.2 (75 psi). Calendered pale crepe with no mercuric oxide set in quinone dioxime and calendered pale crepe containing 2 parts of quinone dioxime, when allowed to stand at room temperature, showed no signs of vulcanization.
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