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Comparison of tensile characteristics (modulus, strength) measured for bought-in laminates and also laminates manufactured in-house with published data has proved the testing procedure to be sound and compression molding to give composites of good quality. In the theoretical domain, the micromechanical approach was used to predict engineering constants such as the longitudinal, transverse and shear moduli that characterize the laminate in its principal directions. For the off-axis loading, macromechanical abstraction was applied and the angular dependencies of the above composite parameters were further supplemented by those for the Poisson ratio and the ultimate strength. Regardless of the theoretical approach used, the error of the predictions relative to the experimental data does not exceed 1 0 percent.

Gaseous ethylene and propene were photolysed with varying amounts of added nitrogen, oxygen, and other gases. The product analysis and variation of yields with added gas are consistent with the major primary reactions (i)-(v) for which the primary quantum yields were estimated. Several other minor primary reactions were found. The C2H4 + hv(A = 185 nm) + C2Ha + H,; 4 = 0.68 -+ C,H2 + 2H ; 4 = 0.20 --t C2H3+ H; + = 0 * 1 6 C3Hs + hv ( A = 185 nm) + CH2:CHCH,* + H ; 4 = 0.41 + C2H3* + CH,; 4 = 0.36 reactions are inhibited by the addition of inert gases ranging from He to CO,; the inhibition is, within experimental error, the same for each additive. Higher pressures were needed to inhibit the ethylene photolysis than other olefins studied and the effect is attributed to the smaller collision diameter of the excited state in ethylene. The results for propene can be explained by a mechanism involving two excited intermediates, only one of which is read i I y quenched .WE have shown that the gas-phase photolysis of simple olefins such as the butenes and pentenes can be inhibited by the presence of additives such as nitrogen, argon, and carbon dioxide. Owing to the peculiar effect of pressure on the yield of the geometrical isomer when either but-2-ene or pent-2-ene is photolysed, the results could be interpreted in terms of collisional deactivation of the singlet Rydberg state. In propene and particularly in ethylene the Rydberg state is found at higher energies than in other olefins and it is possible to excite only the V ( x , x * ) state rather than the Rydberg state, so it seemed worthwhile to conclude our studies by examining the pressure effects in these compounds.

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