Approximate theories of gelation

Inter‐ and Intramolecular Crosslinking Kinetics: Partitioning According to Number of Crosslinks

“…The ratio of intramolecular to intermolecular crosslinking reaction rate, denoted l 0 by Ahmad and Stepto, [16] can be expressed according to Equation (31) as:…”

“…of gelation that incorporate intramolecular crosslinking into the statistical framework [15,16] bear the same disadvantage.…”

Universal Cyclic Topology in Polymer Networks

“…Theoretical efforts have addressed the delay of the gelpoint due to loop formation [25][26][27][28]; however, the intrinsic dependence of the cyclic topology on the condition under which the polymer network is formed as well as the inherent relations between different orders of loop structures are unknown [29,30]. Experimental techniques such as rheology/spectroscopy and multiple-quantum NMR can provide semi-quantitative information related to the loop structure [31][32][33].…”

Application of Ahmad-Rolfes-Stepto theory to the analysis of gel points in aliphatic- and aromatic-based poly(ether-urethane) networks

“…Also included in Table 3 are values of b for some of the aliphatic polyester systems reported previously. 11,12 For all the systems summarized in Table 3, comparison of the values of b shows clearly that the AÈRÈS theory, because it removes the ambiguity of which average value of to use, provides much more reprec ext sentative values of b that lie between the extreme values obtained using the AÈS theory. The aliphatic-based polyurethane systems show the expected decrease in b as triol molar mass increases, because of the increased proportion of the more Ñexible polyoxypropylene segments in the smallest ring, as represented by the higher ratio in Table 3.…”