BRIEFS UNSATURATED POLYESTER RESINS FROM EPOXIDES AND ANHYDRIDES
Commercial polyester resin is prepared using propylene oxide in lithium chloride-catalyzed reaction at 125' C. with maleic anhydride, phthalic anhydride, and minimum propylene glycol to regulate molecular weight. Subsequent heating of resin to 200' C. for 2 to 3 hours improves reactivity with styrene by converting from maleate to fumarate form. Addition of a small amount of phosphoric acid prevents resin darkening. Properties of polyester and resin with styrene after curing compare with products less economically made from propylene glycol by polyesterification. Latitude in composition of polyester is indicated.
H.G. Waddill, J. G. Millgan, and W. J. Pefifiel, Jefferson Chemical Co., Inc., Austin, Tex. IND.ENG.CHEM.PROD.RES.DEVELOP.3, 53-55 (1964) HEAT STABILITY OF BROMINATED EPOXY RESINS
Several factors influence the high temperature performance of bromine-containing epoxy resins. Heat distortion temperatures and weight changes at 300°,400', and 450' F. are useful standards for comparison. A beneficial effect is realized from a decrease in the amount of hydrolyzable chlorine in some commercial brominated epoxy resins. Addition of nonhalogen-containing epoxy resins, lowering the bromine content, and, in many cases, the presence of small amounts of antimony trioxide further improve the properties. The type of curing agent is of great importance, the best results being obtained with anhydride hardeners. Aminetype converters are inferior to a boron triff uoride-monoethylamine complex. Epoxy resins based on tetrabromobisphenol A have better high temperature properties than resins based on the asymmetric 2,4,6-tribromo-3-hydroxybenzoicacid.
Bart J . Bremmer, Benzene Research Laboratory The Dow Chemical Co., Midland, Mich. IND.ENG.CHEM.PROD.RES. DEVELOP. 3, 55-GO (1964)
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CHEMICAL ENGINEERING CATALOG
8
NEW YORK 22, N. Y. Circle NO. 5 on Readers' Service Card
430 PARK AVENUE
REINHOLD
PUBLISHING CORPORATION
PROCESSING AND FABRICATION OF A HIGH-TEMPERATURE FLUIDRESISTANT FLUOROCARBON ELASTOMER
Fluorocarbon elasromers which are resistant to solvents and functional fluids at high temperatures meet many current needs in the aircraft, missile, automotive, and chemical industries. Copolymers of vinylidene fluoride and hexafluoropropylene represent one class of high strength elastomers possessing resistance to hear and compression ser in the presence of destructive fluids that makes them widely applicable at temperatures from 400' to 600' F. Because of their inertness and high coefficient of thermal expansion, as well as the extended curing conditions and high molecular \\.eight required to achieve optimum properties, special compounding, processing, and fabricarion techniques may be required to produce parts comparable to those of hydrocarbon rubber. These parts should be pliable during processing, free from voids during curing, uniform in dimension, and bondable to standard substrates. This report describes rhe application of these rechniques to Fluorel elasromers in making seals, gaskets, O-rings, rolls, valves, and tank linings. L). A . Stizrrs and P. Co., St. Paul, .l.iinn. IND. E S G .
for complete capacity range
P L
CHOICE of SPRAY PROJECTION 4
D. Lanin, -4linnesota .Mining and Manufacturing
CHELI. PROD.RES. DEVELOP. 3, 61-67 (1964)
MODIFIED ACRYLIC ELASTOMERS AND THEIR VULCANIZATION WITH A PEROXIDE-COAGENT SYSTEM
The design of polyacrylic elastomers having improved low temperature flexibilities is discussed in terms of their chemical structure. Compounding characteristics were related to a structure sensitivity study. Resistance to oxidative degradation of a series of acrylic rubbers having good low temperature properties was determined. A peroxide-coagent vulcanization system was developed which imparts good resistance to oxidative degradation a t elevated temperatures.
These WhirlJet spray nozzles all produce the same type of spray. The difference is in body designs to give a choice in spray projection to meet installation needs. For better selection, dependable performance and prompt service we invite you to consider Spraying Systems as your source of spray nozzle supply. WRITE FOR CATALOG 25.
SPRAYING SYSTEMS CO. 3755 Randoloh Street. Bellwood.
Illinois
Morris A . Mendelsohn, Westinghouse Research Lnboratories, Pittsburgh, Pa. IND. ENG.CHEM.PROD.RES.DEVELOP. 3,67-72 (1964) Circle NO. 27 on Readers' Service Card
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NO. 3
MARCH 1964
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