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Branched polystyrenes have been prepared via atom transfer radical polymerisation using 1,6-bismaleimidohexane as the branching agent in two reaction systems of anisole or anisole along with N-methyl pyrrolidone (NMP). The polymerisation kinetics was studied using gas chromatography. The formation mechanism, the development of branching, the changes in molecular weight and polydispersity of branched polymers were analysed using triple detection size exclusion chromatography. The results showed that the formation mechanisms of branched polystyrenes were almost the same in both the reaction systems. The relative molecular weights were also similar at the same conversion of styrene in the two reaction systems because of similar contents of the pendent vinyl groups between the two reaction systems. However, higher absolute molecular weight and higher branching degree of the branched chains were obtained in the anisole with NMP than that in the anisole alone at the same styrene conversion.

The oxidation behavior of grain-refined Cu–7.0 Cr alloy (GR Cu–7.0 Cr) in air at 973–1,073 K was investigated in comparison with normal casting Cu–7.0 Cr alloy (CA Cu–7.0 Cr). The oxidation of CA Cu–7.0 Cr alloy nearly followed parabolic law, while the oxidation kinetics of GR Cu–7.0 Cr slightly deviated from parabolic law. Both alloys almost produced multi-layered scales consisting of the outer layer of CuO and the inner layer of mixed Cr2O3 and Cu2O oxides plus internal oxidation zones of chromium. The grain-refined Cu–7.0 Cr alloy produced a more amount of Cr2O3 in the inner layer of the scale, and thus was oxidized at much lower oxidation rate than that of CA Cu–7.0 Cr with normal grain size. The experimental results indicated that the differences in oxidation behavior between two alloys may be ascribed to the different size and spatial distribution of the second-phase particles and the reactive component contents in localized zone.