Absolute propagation constants in vinyl polymerization

Vulcanization of Butadiene Rubber by Means of Cyclic Disulfides. 2. A 2D Solid State HRMAS NMR Study on Cross-Link Structures in BR Vulcanizates

“…Once the 1 H NMR chemical shifts were assigned, HMQC connectivities readily afforded the corresponding carbon chemical shifts. The chemical shifts found were shown to be in good agreement with known literature values, , the determined chemical shifts were all within 2 ppm compared to the calculated values found for the cis and trans monomer units. Larger deviations were, however, found for the vinyl structure.…”

Reactivation of precore mutant hepatitis B virus in chemotherapy-treated patients

“…All of the above‐mentioned results confirm the accuracy, precision, reliability, and robustness of the MLE method for kinetic parameter estimation in copolymerization systems, and the values of estimated kinetic parameters are in the permissible range of methacrylates in free‐radical polymerization (Bywater, 1999; Hutchinson et al, 1997). For all cases discussed above, convergence is stable and rapid.…”

Reevaluation of the Propagation Rate Constant in the Radiation-Induced Cationic Polymerization of Isobutylene in Solution

“…It will now be shown that the k p + value obtained from eq 3 is the same as that derived from the so-called Hayashi−Williams equation ,, (eq 4) which predicts that in the limit of no impurity termination the rate will assume a maximum value and depend on the square root of the rate of initiation R i and therefore also of the radiation dose rate. , The experimental parameters of R / m = 7.5 × 10 -7 s -1 and S = 1.82 × 10 -3 M yield a value for R i through eq 6 of 1.37 × 10 -9 M s -1 , and substitution in either eq 4 or eq 5 along with the previously assumed value of k t = 2 × 10 11 M -1 s -1 leads to k p + = 0.91 × 10 4 M -1 s -1 , which is identical with the k p + value reported by Plesch . Accordingly, it is clear that this value for k p + is in fact predicated on a single termination step that occurs only as a result of ion recombination with a mean lifetime, τ i , for the propagating ion given by τ i = c / k t c 2 = 1/ k t c = 1/( R i k t ) 1/2 .…”

“…It will now be shown that the k p + value obtained from eq 3 is the same as that derived from the so-called Hayashi-Williams equation 4,17,18 (eq 4) which predicts that in the limit of no impurity termination the rate will assume a maximum value and depend on the square root of the rate of initiation R i and therefore also of the † E-mail: ffwilliams@utk.edu.…”