About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Paper
MODULUS OF TIGHTLY CROSSLINKED POLYMERS RELATED TO CONCENTRATION AND LENGTH OF CHAINS.
Abstract
The equilibrium shear modulus G of network polymers increases rapidly with the chain concentration nu when nu greater than equivalent to 10** minus 3 mol/cm3. This behavior is accounted for by the equation G equals PHI //n nu RT GAMMA (1/ lambda //m), where PHI //n(equals r//i2/r//02) may depend on n, the mean number of backbone bonds per chain, and GAMMA (1/ lambda //m) is a function of 1/ lambda //m, the mean fractional extension of chains in the isotropic (undeformed) network. In turn, 1/ lambda //m equals (PHI //nC//n/q2n) one-half , where C//n is a characteristic ratio (equals r//02/nl2) which, for short chains, depends on n, and q is a constant determined by bond angles and lengths. An expression for GAMMA , suggested by a well known equation for a regular cubic network of freely jointed volumeless chains, is derived and then shown to be approximated closely by GAMMA //a//p//p equals 5 lambda 2//m/(5 lambda 2//m minus 6) for 1/ lambda //m less than 0. 88. The moduli of some 26 ethyl acrylate-dimethacrylate networks, for which 5 less than n less than 23 and 2 multiplied by 107 less than G less than 5 multiplied by 109 dyn/cm**2, were represented by the equation through use of effective parameters, phi //e//f and C//e//f, which are independent of n.