Polysiloxane, as an organic silicon polymer， can be chemically modified by block copolymerization. Because of its abundant raw materials and excellent properties of modified products, it has been extensively studied by scholars. In this paper, the research progress of polysiloxane block copolymers at home and abroad was reviewed. Some kind of polysiloxane block copolymers modified by polyurea, polyurethane, polyether, polyamide and polyimide were mainly introduced. Also, its performance and application were summarized, and the prospect of its application was forecasted.

A new method for preparation of polystyrene nanoparticles by using a method of RAFT living polymerization was studied.Firstly,small molecular reversible addition⁃fragmentation chain transfer agent,three thiocarbonate (DBTTC),was synthesized for active polymerization.Then the emulsifier free emulsion polymerization method was used to prepare styrene polystyrene latex with narrow particle size distribution using itaconic acid as the monomer and ammonium persulfate as initiator.Effects of the molar ratio of St/IA,molar ratio of acetone/water,reaction temperature and amount of DBTTC on the latex particle size were studied respectively.The latices were characterized by Malvern nanosizer,TEM,GPC,surface tension and conductometric titration.The results show that when the temperature is 78 ℃,the molar ratio of St/IA is 10,and the molar ratio of DBTTC/St is 0.064,the molar ratio of acetone/water is 4∶6,the polystyrene nanometer latex particles with average particle size of 98 nm can be obtained.

With itaconic acid (IA) and 1,4  butanediol (BDO) as the raw materials, the resultant hydroxyl terminated aliphatic unsaturated polyesters (PBI) were prepared. The unsaturated polyurethane was prepared with PBI as the soft segment and toluene diisocynate (T DI) as the hard segment. The effect of its reaction conditions on the mechanical properties of the unsaturated polyurethane was also investigated. It was found that the film products with the optimum properties were obtained under the material mass ratio o f TDI and PBI 1 ∶ 1.5, the reaction temperature 80 ℃ , optimum reaction time 2 h, with dibutyltin dilaurate in an amount of 1% as the catalyst. Combining with benzoyl peroxide in an amount of 1%,as an initiator, the film of the unsaturated polyurethane was smooth, transparent and level. The hardness was 6H, and the adhesion property was A grade.

Hydrophobic modification of 152 magnesium hydroxide sulfate hydrate (MHSH) whisker was studied using ethyl alcohol as the solvent and heptadecafluoroalkylsilane（ACFAS） as modifier. The morphology, crystalline state and composition of products before and after hydrophobic modification were characterized by scanning electron microscopy (SEM), Xray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and contact angle measurements (CAM), respectively. The characterization results indicated that 152 MHSH was successfully coated by the modifierand the hydrophobic 152 MHSH whiskers were obtained. The ideal hydrophobic surface with water contact angle of 126° was achieved when the whisker was treated for 1 h. FTIR, XRD, SEM and EDS analysis showed that there were no change in the crystal form of whiskers, and ACFAS molecules were successfully coated on the surface of MHSH whiskers.