Ferromagnetic metal‐based materials display interesting properties for microwave applications. Here the authors report obtaining ferromagnetic monodisperse particles in the nanometer size range by the polyol process. By accurate control of the particle size the influence of the particle upon the microwave permeability could be studied. Three different behaviors are detected in a size range varying by over two orders of magnitude, in which the change from a polydomain to a monodomain configuration occurs.

A new ultraviolet (UV)-cured waterborne polyurethane (WPU) mainly composed of ionic soft segments, imide groups, and a new water-soluble UV-cured cross-linking agent containing both C¼C bond and carboxy group was prepared. The ionic soft segments were prepared by 1,6-hexamethylene diisocyanate , poly(propylene glycol)-600, and dimethylol butanoic acid. The imide groups were introduced into polyurethane by extending them with pyromellitic dianhydride (PMDA). The new water-soluble UV-cured cross-linking agent (MLGLY) was synthesized by hydrophilic maleic anhydride and glycerol oligomer. The particle size and the viscosity of the new anionic WPU as well as the water swelling, gel content, mechanical properties, and thermal stability of the UV-cured WPU cast films were investigated. The results showed that the best performance of WPU was obtained with 0.024 mol of PMDA and 5 wt% of MLGLY.

Under the aerobic condition, using tap water as solvent, the super absorbent resin was synthesized by solution polymerization of acrylic acid-sodium acrylate, The result showed the water absorbency of last production in tap water was 578g/g, when the concentration of monomer was 25%, the neutralization degree of monomer was 80%, the amount of initiator and crosslinking agent was 0.15% and 0.07% respective, the react temperature was 90°C and the time of reaction was four hours. the crosslinking action of crosslinking agent was not influenced, although tap water was used as solvent. Which will has important directive significance to the large-scale industrial production of high polymer absorbent resin.