Preparation And Properties Of Hydroxyl-Terminated Polybutadiene/Cyanate Ester Composites

Cyanate resin(CEs)is one of the four high-performance engineering plastics.Its unique analytical structure makes it excellent in dielectric properties,moisture absorption properties,mechanical properties and good process properties.It is widely used in aviation,aerospace,electronics and other industries.However,after the CEs are cured,they contain a large number of rigid highly symmetric triazine ring structures,which leads to the brittleness of CEs,so in many cases it cannot meet the application requirements.The rubber elastomer toughening modified cyanate resin is considered to be the most effective method for toughening cyanate resin.In this paper,Bisphenol A Dicyanate Eater Resin(BADCy)was toughened and modified with different molecular weight and different content of Hydroxyl Terminated Polybutadiene(HTPB).The mechanical properties of HTPB/CEs composites with VinylPOSS as filler were studied.The curing reaction of each system was studied by DSC,gelation time test and FT-IR.The mechanical properties,water absorption,heat resistance,dielectric properties and cross-section morphology of the materials were tested and studied.The main contents and conclusions are listed as follows:First,the curing behavior of HTPB modified CEs system was studied.It was found that the introduction of HTPB can reduce the peak exothermic temperature and gelation time of CEs.For HTPB/CEs system,the exothermic peak temperature increases with the molecular weight of HTPB and decreases with the increase of HTPB content;the gelation time increases first and then decreases with the increase of HTPB molecular weight,and decreases with the increase of HTPB content.As the molecular weight of HTPB decreases or the content increases,the water absorption,heat resistance and dielectric properties of HTPB/CEs composites deteriorate.The mechanical properties of HTPB/CEs composites increase with the decrease of HTPB molecular weight,and with the content of the HTPB/CEs composites increases it first becomes better and then worsens.The crosssectional morphology of the materials can explain this phenomenon.Second,in order to improve the dielectric properties and heat resistance of HTPB/CEs,the self-made Vinyl-POSS was added to the blend system based on HTPB/CEs.The effect of the addition of Vinyl-POSS on the curing behavior of the system was discussed.The properties of the composites were tested and analyzed.The results show that the water absorption of the composites increases slightly with the increase of the content of VinylPOSS.The mechanical properties first increase and then worsen with the increase of Vinyl-POSS content.The dielectric properties also deteriorated with the increase of Vinyl-POSS content,and the heat resistance of the material increased with the increase of Vinyl-POSS content.