Study on Reaction Kinetics of UV-curing Coatings of Epoxy Acrylate and Monte Carlo Simulation of Itroxide-mediated Living Free-radical Photopolymerization

Abstract: In this thesis, the effects of cationic, free radical and hybrid photoinitiators (including free radical and cationic initiators) on the kinetic performance in UV-curing system of the epoxy acrylate have been studied, as well as we have investigated the in situ photo-stabilizing performance of Reactive Hindered Amine Piperidinol Derivatives (r-HAPD) applied in UV-curing coatings system above. The author used a Monte Carlo simulation algorithm to investigate the reaction kinetics and molecular weight distribution of free-radical photopolymerization of r-HAPD, which was consistent with the characteristic of Living free-radical photopolymerization or not. The main conclusion of our work are as follows:1. Three r-HAPD: 4-methacryloyl-l,2,2,6,6-pentamethyl-piperidinyl (MPMP), 4-acryloyl-l,2,2,6,6-pentamethyl-piperidinyl (APMP), and 4-acryloyl-2,2,6,6-tetra-memyl-piperidinyl (ATMP) were synthesized by'direct transesterification between hindered piperidinol and a, p-unsaturated ester. And their structure and composition has been characterized by modern analytic techniques, such as Fourier Transfer infrared (FTIR) etal..2. The conversion of epoxy acrylate/DVE-3 system decreases with the increment of concentration of DVE-3 . With the increment of concentration of AE, the concersion of epoxy acrylate/AE system decreases. The photo-curing rate of hybrid initiating system was the fastest than that of cationic or free radical photoinitiators. The photo-curing rate of hybrid initiating system depended on the blending proportion of free radical and cationic initiators.3. The anti-oxidation performance of DVE-3 is not as good as that of AE. The photo-stabilizing performance of r-HAPD, such as ATMP APMP and MPMP, are excellent applied in the UV-curing coatings, and superior to the corresponding commercial HALS such as Tinuvin260.4. Using Monte Carlo simulation algorithm to investigate the reaction kinetics of Living free-radical photopolymerization of Reactive Hindered Amine Piperidinol Derivatives (r-HAPD). The effects of reaction conditions on the elementary reactions of the polymerization process were investigated by using Monte Carlo simulation, and partly verified by the experimental results. A systematic study was performed to investigate the dependence of kinetic behavior and molecular weight distribution on reaction parameters such as the rate of r-HAPD to transfer r-TEMPO, the homolytical rate constant of free radical initiator, the rate constant of the polymerization and the coupling termination, the concentration of oxygen, the ratio of initiator added. Monte Carlo simulation results demonstrate the reaction kinetics of r-HAPD were consistent with the characteristic of controlled/living free-radical polymerization, which is the linear relationship between the molecular weight and monomer conversion as a kinetic indication of the controlled/living character for photo-induced free radical polymerization of r-HAPD…
Key words: r-HAPD; Reaction kinetics; photo-stabilizing; Living free-radical photopolymerization ; Monte Carlo simulation

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