Preparation And Technology Of Modified Boron Phenolic Resin/Basalt Fiber Composite Materials

To solve the problems of galvanic corrosion in the field of marine pipelines and instruments and find the alternative materials for metal connections,fiber-reinforced resin-based composite materials are widely studied and developed.In this study,basalt fiber?BF?was used as the reinforcement and boron phenolic resin?BPF?,which also has high temperature resistance and good mechanical properties,was chosen as the matrix.After the resin was modified by potassium titanate whiskers,potassium titanate whisker modified boron phenolic resin/basalt fiber composite material was prepared by a molding process.The high temperature resistance and mechanical properties of the resin matrix and basalt fiber composite were studied,which can provide a reference for the application of fiber-reinforced resin-based composite materials in the marine environment.In this experiment,fourier transform infrared spectroscopy?FT-IR?,thermal gravimetric analyzer?TGA?,differential scanning calorimetry?DSC?,scanning electron microscopy?SEM?and so on were used to characterize the composition and the group changes of the resin,thermal properties and the surface morphology.The insulation resistance,mechanical properties and the effect of high temperature ablation on the properties of the composite materials were measured too.Boron phenolic resin was prepared by salicylol method.The preferred ratio of synthesizing boron phenolic resin was determined by changing the ratio of reactants,i.e.phenol:paraformaldehyde:boric acid=1.0:1.6:0.33.By changing the resin ratio,curing time and the DSC curve,the optimal molding process conditions were determined that the resin ratio is 42%,the curing temperature and time are 180? and 3 h,respectively.Potassium titanate modified boron phenolic resin was prepared by in-situ formation,which was mixed with basalt fiber to prepare the composite material.The best addition of potassium titanate whisker is 4%.The incorporation of potassium titanate whisker in the composites changed the two-dimensional connection of basalt fiber and boron phenolic resin matrix into a three-dimensional connection,which improved the mechanical properties of the composites greatly.The maximum tensile strength and bending strength are up to 521 MPa and 690 MPa,respectively,which is about twice the strength of carbon steel at room temperature.However,after high temperature ablation,the mechanical properties of the composite material gradually decreased.The composites also showed high insulation and the surface and volume resistivity were both more than 10¹⁶?·cm.When immersed in seawater,the insulation resistivity drops sharply in the first three days,it finally reached a stable value of about 10⁹?·cm after 400 h.The insulation resistivity of the composites still remained high values of10¹⁴?·cm after being calcinated at 800°C.The composite material has potential application value in the long-term insulation anti-corrosive material.