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:
Acidic functionality on the surface of oxidized carbon blacks modifies the cure processes of the tetrafunctional epoxy resin MY720 (largely tetraglycidyldiaminodiphenylmethane, TGDDM) crosslinked with diaminodiphenylsulfone (DDS). In the early stages of the cure (up to 60 min at 140°C), the rate of consumption of TGDDM and DDS and the rate of production of the 1 : 1 adduct are increased, together with an increase in the production of ether functionality. These chemical changes are associated with an increase in exotherm. an increase in gel fraction, and preferential adsorption of the amine curing agent on the carbon surface. During the middle stages of the cure (after 180 min at 140°C), the acidic carbon black has a slight retarding effect on the cure; but, on completion of the later stages of the cure, the effect of the carbon surface functionality diminishes, and, in contrast to earlier studies with difunctional epoxy resins, neither the total cure exotherm nor the final glass transition temperature is affected greatly. We attribute this difference to the greater ease of etherification reactions for the tetrafunctional resin compared to the difunctional case. Basic functionality on the surface of carbon black (induced by carbon dioxide treatment) has a slight retarding effect on TGDDM consumption in early stages of the cure. Less adsorption occurs on the basic carbon than on the acidic carbon, and the adsorbed material appears to be rich in resin. These results imply that treated carbon surfaces may advance or retard the local cure state of an MY720-DDS matrix, but will not affect markedly the final cure state.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1990.070400109
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