Phase behavior and photocrosslinking kinetics of semi‐interpenetrating polymer networks prepared from miscible polymer blends

Abstract

Mixtures of polystyrene derivatives (PSCS) and poly(vinyl methyl ether) (PVME) were made photocrosslinkable by chemically labeling PSCS chains with photoreactive anthracene. Miscibility of these anthracene-labeled PSCS/PVME blends was examined by light scattering under several crosslinking conditions in the one-phase region via photodimerization of anthracenes. As the reaction proceeds, the coexistence curve of PSCS/PVME blends shifts toward the low temperature side. By following the changes in concentration of anthracenes with irradiation time, it was found that the crosslinking reaction of PSCS chains in the blends does not follow the mean-field kinetics. However, it can be well expressed by the Kohlrausch-Williams-Watts (KWW) relaxation mechanism, indicating that the crosslinking reaction proceeds inhomogeneously in the blends. By scaling the reaction time with the average reaction rate obtained from the KWW equation modified for the reaction kinetics, all the crosslinking data obtained in the miscible region of the reacted blends fall on a single master curve. These experimental results suggest the universal behavior of the photocrosslinking kinetics obtained under the ''shallow quench'' conditions in the region far away from the coexistence curve of the reacting blends.

Effects of molecular weight on the local deformation of photo-cross-linked polymer blends studied by Mach–Zehnder interferometry

“…This PEA/PEA-A combination was chosen to avoid the phase separation caused by the formation of semi-interpenetrating polymer networks. 9 By fluorescence microscopy, it was determined that a PEA-A/PEA(40/60) blend after 420 min of photo-cross-link remains structureless for 3 h of annealing at 80 1C. The chemical structure of PEA-A is illustrated in Figure 1.…”

Phase behaviour of random copolymers and crosslinked homopolymer blends

“…An early review of crosslinked polymer blends can be found in [63]. Related systems are, e.g., crosslinked blends in solution [64], non-permanently crosslinked polymer blends [65], interpenetrating and semi-interpenetrating networks, [66][67][68][69] and [70,71], crosslinked diblock copolymer melts [72,73], nematic elastomers [74] and mixtures of crosslinked polymers with nematic liquid crystals [75].…”