Carboxyl terminated polyamide 12 chain extension using a dioxazoline coupling agent

Kinetic and Mechanistic Studies of Carboxylic Acid–Bisoxazoline Chain‐Coupling Reactions

“…At the temperatures generally used for coupling reactions involving oligomers or polymers, that is, above 180 °C, bisoxazoline reactivity varies in the order pybox > mbox > pbox . The activation enthalpy obtained for bisoxazoline mbox (77 kJ · mol −1 ) is in a good agreement with the Arrhenius activation energy given by Chalamet ( E a = 79.5 kJ · mol −1 ) 14. It is difficult to explain the lower activation enthalpy and entropy found for pbox when compared with mbox (Table 2), since electronic effects and steric interactions should not be too different for these compounds.…”

Monte Carlo simulation of diffusion effects on chain‐extension reactions

“…The reactant degradation, which can change the chain‐extension kinetics especially under extrusion conditions, is also an important factor affecting the diffusion limitations in the coupling reaction 4, 6, 7. Scheme (III,IV) accounts for this effect.…”

“…Kinetic constant K B was obtained from the calculation based on the corresponding rate constant at lower temperatures and activation energies. For K B , a value of 2 × 10 −4 kg mol −1 s −1 at 120 °C with an activation energy of 79.5 kJ mol −1 was reported in ref 4…”

“…The reaction behavior of carboxyl terminals contained in the initial polymers can be classified into three groups: blocked, coupled, and unreacted. However, these elementary reactions do not include a degradation effect, which can affect the chain‐extension efficiency, especially under extrusion conditions 4, 6, 7. In this simulation, only the degradation reactions of MEA and CA are considered because they have more effect on the diffusion effects of the coupling reaction, that is, Scheme (b).…”

Chain extension of PA1010 by reactive extrusion by diepoxide 711 and diepoxide TDE85 as chain extenders

“…Beyond the critical value of n, the platform becomes more and more acclivitous and the coupling effect keeps rising during the whole range. On the assumption that n is 0.02, 0.05, and 0.1, Figure 5(a, b, and c) simulates these three conditions by ideal kinetics model and Runge–Kutta numerical method,15–16 which is concretely expressed in the . Despite its difference from actual instance, the model accords well with the analysis above qualitatively.…”