ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The effects of cure time, temperature, and initiator concentration on the mechanical properties of a vinylsilicone resin cured with dicumyl peroxide were investigated. The resin had a second-order transition extending from below 25 to about 100°C. The transition region broadened as the degree of crosslinking increased. Measurements of physical properties at room temperature were very sensitive to small temperature changes. Ultimate strength measurements were particularly unreliable indicators of degree of cross linking because of large random variations and because they depended upon other structural factors besides crosslink density. The best test of degree of crosslinking was modulus measurements above the transition temperature of the resin. Such measurements have a sound theoretical basis and the practical advantage of being insensitive to small temperature changes. Modulus measurements have the additional advantages of being a nondestructive test with a high degree of inherent precision compared to other physical tests. A concentration of about 1.5 wt.-% dicumylperoxide was optimum for crosslinking the vinylsilicone resin studied. Maximum crosslinking was obtained when the peroxide was utilized slowly a t low temperatures for long cure periods. When a 4-hr. cure was used the optimum temperature range was 125 to 135°C.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1962.070062213
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