The problem of the delayed crosslinking arising due to the diffusion of a crosslinker molecule from a vector particle within a thermoset polymer matrix is discussed. The crosslinker molecules, initially embedded in the vector particles, diffuse from the particle to the polymer matrix and react with the functional groups grafted to polymer chains. The two‐step diffusion crosslink kinetics is studied theoretically on the example of polyethylene functionalized with anhydride groups reacting with 1,4‐butanediol as a crosslinker molecule. This provides the independent of time limiting distribution functions of the concentration of crosslinks, unreacted and intermediate functional groups, which are shown to be rather sensitive to system parameters as rates of chemical reactions, ratio of diffusion coefficients of matrix to vector particles, stoichiometric composition of the reactive groups, etc. The nonmonotonic distribution of the crosslink concentration around the vector particles at certain range of the parameters is revealed.
The mode of continuous detonation combustion of hydrogen in the annular combustor of a model of a detonation air-breathing ramjet at the approach air stream Mach number 5.7 and a stagnation temperature of 1500 K was experimentally detected for the first time in a pulsed wind tunnel. The thrust and fuelbased specific impulse of the ramjet model were 1550 N and 3300 s, respectively. 相似文献
