A series of optically active nanoparticles composed of helical substituted polyacetylene is prepared via emulsion polymerization. A specifi c organic solvent is required for solid substituted acetylene monomers to undergo emulsion polymerization. The effects of this organic solvent are investigated. Its amount is found to be decisive for obtaining stable polymer emulsions. The helical conformations of the substituted polyacetylenes in nanoparticle state are identifi ed with the help of CD and UV-vis spectra. A blue shift occurs in CD and UV-vis spectra of some of the polyacetylene emulsions. The underlying driving force for the blue shift is discussed, and an emulsion polymerization mechanism is proposed.
Cellulose insulation paper is the main component of oil‐paper insulation systems in oil‐immersed transformers. However, the poor thermal conductivity and thermal stability of the cellulose can lead to thermal ageing. It is critical to address this issue by improving the performance of cellulose, nano‐SiC‐modified cellulose models were established by molecular simulation, while nano‐SiC composite papersheets were prepared based on the simulation results, and the effects of different contents of nano‐SiC on the papersheets were investigated. Macroscopically, doping nano‐SiC particles can enhance the thermal stability of cellulose; compared with the unmodified papersheet, the thermal conductivity and tensile strength of the modified papersheets are increased by 44.3% and 42.8%, respectively. The degree of polymerisation of the modified papersheet decreased more slowly than that of the unmodified papersheet under accelerated thermal ageing, showing that the modified papersheet has better anti‐ageing properties. Microscopically, with the addition of nano‐SiC, the simulations showed that the mean square displacement of the cellulose decreases dramatically and the distribution of the free volume becomes difficult to disperse, which corresponds to the decrease in porosity in the experiments. As a result, this research provides a way for improving the thermal‐mechanical properties of cellulose that has practical application significance.
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