Study On High Performance Silica-based Special Rubber Nanocomposites

Due to the unique high elasticity,rubber plays key roles in many fields.With the rapid development of automobile industry and aviation industry,the demand for rubber material is increasing,and the performance of rubber material required in various fields is also increasing.It is an effective way to improve the properties of rubber nanocomposites by reinforcing rubber matrix with nano-particles.Nano silica（SiO₂）is widely used in rubber reinforcement because it does not depend on petroleum resources and has good reinforcing effect on rubber.However,it also has the problems of easy agglomeration and poor compatibility with rubber,which greatly limits its application as rubber reinforcing agent.At present,use one filler individually can not enable rubber to meet the higher and higher performance requirements.Nanocomposites could introduce the special functions and the synergistic effect of each component.Therefore,the development of nanocomposites has become a new research hotspot in the field of rubber reinforcement fillers.This thesis takes nano SiO₂as the main filler,introduces different functional fillers,and endows these functional fillers with a special structure.Different SiO₂-based nanocomposites were prepared by combining SiO₂with these structured functional fillers.The network structure and interaction between the nanocomposites and the rubber matrix in SSBR/BR and HNBR were studied,and the reinforcing mechanism of the nanocomposites on rubber was revealed.This work provided new ideas and methods for the application of functional fillers in rubber reinforcement.The primary coverage as follows:1.The C₃N₄/SiO₂nanocomposites were prepared by combining SiO₂and g-C₃N₄with strong structure through in-situ growth method.The C₃N₄/SiO₂-SSBR/BR nano composites were obtained by filling C₃N₄/SiO₂into SSBR/BR.The average particle size of SiO₂is about 15nm,and due to the synergistic effect of C₃N₄and SiO₂in C₃N₄/SiO₂,its dispersibility in SSBR/BR matrix is improved,and there is a strong interaction between C₃N₄/SiO₂and SSBR/BR,which shows an obvious reinforcing effect on SSBR/BR.The tensile strength is greatly improved up to 20.58 MPa.Compared with SiO₂-SSBR/BR,the wet skid resistance of C₃N₄/SiO₂-SSBR/BR nanocomposites is improved,while the rolling resistance,Akron wear volume and heat built-up is reduced by 51%,19.5%,24%,respectively.2.A two-dimensional functional filler,titanium dioxide（Ti O₂（s））,was designed and prepared,and 3-aminopropyl trethoxysilane（APTES）was used to introduce reaction sites on the surface of Ti O₂nanosheets.After that,SiO₂was grown in situ on the surface of Ti O₂（s）by electrostatic assembly method to prepare Ti O₂（s）/SiO₂nanocomposites.Ti O₂（s）/SiO₂-SSBR/BR nanocomposites were obtained by combining SSBR/BR with Ti O₂（s）/SiO₂.In Ti O₂（s）/SiO₂,the size of Ti O₂（s）is about 200nm,with a thin thickness.SiO₂was uniformly anchored on the surface of Ti O₂（s）.Due to the synergistic effect of Ti O₂（s）and SiO₂,the dispersion of Ti O₂（s）/SiO₂in SSBR/BR was significantly improved,the filler network was weakened,and the interaction between Ti O₂（s）/SiO₂and SSBR/BR was significantly enhanced.As a result,Ti O₂（s）/SiO₂-SSBR/BR showed better mechanical properties compared with SiO₂-SSBR/BR,In addition,the rubber molecular chain slips along the orientation of Ti O₂nanosheets during stretching,which promotes stress dispersion and further improves the mechanical properties of rubber.Compared with SiO₂-SSBR/BR,the wet skid resistance of 2%Ti O₂（s）/SiO₂-SSBR/BR nanocomposites increased by 9.5%,while the rolling resistance decreased by 42.6%,and good wear resistance was maintained.3.In order to solve the problem that Ti O₂nanosheets are easy to stack,Ti O₂was designed as one-dimensional nanobelts and endowed with a large aspect ratio.Ti O₂（b）/SiO₂（Tb S）nanocomposites were prepared by in-situ growth of SiO₂on the surface of Ti O₂（b）that modified by CTAB.Tb S-HNBR nanocomposites were prepared by mixing Tb S with HNBR by mechanical blending method.During the preparation of Tb S,the coating of CTAB on SiO₂prevented the contact among SiO₂,which improved the dispersion of SiO₂.In addition,the modification of Tb S by CTAB grafted organic molecular chains on the surface of Tb S,which improved the compatibility between Tb S and HNBR.Therefore,the mechanical properties of Tb S-HNBR were greatly promoted.The tensile strength and tear strength of 4%Tb S-HNBR reach32.92 MPa and 46.7 k N/m,which increased by 42.8%and 64.9%compared with SiO₂-HNBR,respectively.Tbs-HNBR has a large reinforcing coefficient,and the reinforcing index of 4%Tb S-HNBR reaches the maximum,which proves that 4%Tb S has the highest reinforcing efficiency for HNBR.4.One-dimensional alumina nanowire（Al₂O₃（w））was prepared on the basis of 3.And Al₂O₃（w）/SiO₂（Aw S）nanocomposites and Aw S-HNBR nanocomposites were designed and fabricated by the same method as Tb S.Similarly,Aw S showed good dispersion in HNBR,and the interaction between Aw S and HNBR was enhanced owing to the graft of CTAB.Moreover,it gives full play to the advantage of larger length-diameter ratio to accelerate the dispersion of stress,so that the reinforcing effect of HNBR is obviously improved.2%Aw S has the best reinforcing effect on HNBR.In addition,2%Aw S-HNBR shows good thermal-oxidative aging performance because of the better thermal conductivity of Al₂O₃compared with SiO₂-HNBR.It is verified that the idea and method in 3 are universal through the study of Tb S-HNBR and Aw S-HNBR,which provides a new idea for the better application of functional filler in rubber reinforcement.