Three-dimensional radical polymerization

Abstract

This is an analytical review on kinetics and mechanism of threedimensional radical polymerization (TDRP) of multifunctional vinyl monomers (oligomers) having two or more double bonds per molecule. The period (1960 - 1977) of establishing the fundamental kinetic law of TDRP and the principal characteristics of its mechanism, i.e., microheterogeneity, is briefly described. New intense progress in the field of TDRP (during the recent decade) resulting from the development of new technologies based on this technique (fiber-optic engineering, information technology, etc.) has received much consideration. The methodological peculiarities of investigations on TDRP kinetics and mechanism, which are a result of the complex conditions of highly structured reaction media inherent in TDRP processes, are described. Particular attention is given to techniques of structuralphysical investigation (a consistent complex of methods including ESR, NMR, diffusion and radiation probing, mechanics and thermomechanics) sensitive to structural microheterogeneity in the range 10-6 - 10-4 cm. The perspectives of macromolecular design based on TDRP data are analyzed including latest approaches as the employment of a ‘living’ chain mode. This review covers three monographs in Russian, reflecting three sequential stages of TDRP development from 1960 till 1995 using acrylic oligomers as an example (most of the investigations were carried out at the Institute of Chemical Physics RAS). The bibliography includes 197 references.

Kinetic modeling of an unsaturated polyester resin using two complementary techniques: Near infrared spectroscopy and heat flux sensors

“…Traditionally, thermoset chemistry specialists tend to characterize kinetics from isothermal experiments using chemical group specific detection techniques [5,6] such as SEC, FTIR, or 13 C NMR, their main objective being to establish a detailed reaction mechanism. This first step generally allows defining a simplified kinetic model that can be introduced in process simulation software.…”

Morphological memory of polymeric bodies

“…Solution of these boundary value problems over a wide range of y will allow one to identify the main relations of the microrelief with the speeds of the elementary processes as well as to describe the response of the function φ (υ, τ ) to the change of y and to develop algorithms for calculating the parameters of elementary processes from the experimental data about the function φ (υ, τ ) at different y. Currently, methods for solving such problems and the models of elementary processes are developed, and experimental data, allowing one to judge the main features of the microrelief and to make a phenomenological model of its formation, is accumulated [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For the quantitative study of the relation between the parameters of microrelief and the elementary processes, it is advisable to start with the simplest system, one in which the initiator molecules are rapidly converted into the nuclei of chain macromolecules, their number in the system reaching the value N 1 = C B V 0 .…”

“…Such an interpretation requires detailed information about what was happening in the monomeric solution when the polymerization initiator was introduced. It is known that in such a solution, the nucleation and growth of the polymeric macromolecules occurs, which form the aggregates followed by their assembly into a polymeric body, and the macromolecules on the body's surface form the microrelief [3][4][5][6]. During the transition to the body structure, the condition of each macromolecule can change significantly, depending upon the relaxation time of its state [7,8].…”

Toughening of brittle poly(lactide) with hyperbranched poly(ester-amide) and isocyanate-terminated prepolymer of polybutadiene

“…[11,12]. The synthesis, properties, application, and utility of HBP as polymer additives is well described in the literature [13][14][15][16][17]. Zhang and Sun [8] have studied the effects of HBP on the mechanical and crystallization behaviors of PLA.…”