| Rubber is used extensively because of its excellent high elasticity,nevertheless,high elasticity can only be attained via crosslinking rubber.Despite the fact that traditional crosslinker(sulfur and peroxide)give rubber excellent properties,the crosslinking process forms irreversible covalent crosslinking bonds between rubber molecular chains,which results in high value utilization of scrapped rubber is low,additionally,the crosslinking process produces toxic and unpleasant small,resulting in significant resource waste and environmental pollution.Ionic bond,as a kind of non-covalent bond,has good bond energy and is an ideal crosslinking bond to construct reversible rubber crosslinking network,and it is of great significance to introduce ionic bond into rubber crosslinking network to prepare recyclable and remachinable multifunctional rubber products.Based on this,this paper synthetised a zinc acrylate based crosslinker that can be used to build the crosslinking network structure of styrene butadiene rubber(SBR),realize the recycling and reprocessing performance of crosslinked SBR,and carbon nanotubes were used as conductive filler to prepare rubber composite materials with recycling and electromagnetic shielding capabilities.Specific work is as follows:(1)The zinc acrylate based crosslinker(SZDA)was synthetized by one-pot method with bis[3-(triethoxysilyl)propyl]tetrasulfide(Si69)and zinc acrylate(ZDA)as raw materials.The double bond of ZDA was epoxyed under the formic acid and hydrogen peroxide,and then reacted with the ethoxy group in the structure of Si69 to produce the SZDA.The epoxy reaction of ZDA and the structure of SZDA were analyzed by using fourier infrared spectroscopy(FTIR),raman spectroscopy(Raman),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD)and electron microscopy(EDS).(2)Styrene butadiene rubber was crosslinked by simple blending with open-mill and hot-pressing.Sulfur in SZDA can quickly crosslink with double bonds in SBR with the presence of 2,2-dibenzothiazole disulfide(DM),which ionic bonds are iontroduced into the network.The structure and mechanical properties of crosslinked SBR was characterized by ourier infrared spectroscopy(FTIR),scanning electron microscopy(SEM),universal testing machine,hardness tester and springback test.When the content of SZDA and DM were 20 phr and 10 phr,the tensile strength of crosslinked SBR was 4.32 MPa,the elongation at break was 810.71%.(3)Crosslinked SBR was recycled by solution method.The crosslinked SBR was placed in toluene/chloroacetic acid mix solution,the crosslinked SBR can be dissolved because the ionic interaction exists,which broke the insoluble characteristic of traditional crosslinked rubber.The reprocessed SBR was prepared by the reaction between-COOH on the molecular chain of recycled SBR matrix and the corsslinker with zinc oxide(ZnO),which realize the reuse of recycled rubber.When 20 phr ZnO was added,the tensile strength,and elongation at break of reprocessed SBR were 3.91 MPa,726.14%.(4)Carbon nanotubes/styrene butadiene rubber composites(CNTs/SBR)were prepared by solution and mechanical blending.CNTs were dispersed in solution and then added to the SBR for blending.After drying,they were mixed in open-mill to obtain a dual function composite material with recyclability and electromagnetic shielding.When CNTs were added 20 wt%,the shielding performance of CNTs/SBR materials was 27.29 dB.When the thickness of CNTS/SBR increased from 1 mm to 3 mm,the shielding performance of CNTs/SBR at 10 wt%increased from 21.01 dB to 31.25 dB.The crosslinked SBR was recovered by solution method and ZnO was used as the crosslinker to crosslink the recycled SBR.When the thickness was 3 mm and the content of CNTs was 10 wt%,the shielding performance of the reprocessed CNTs/SBR material was 25.46 dB,and the performance retention rate was 76.18%compared with the original.It shows that the recycled rubber can still be used the matrix of shielding material,which realizes the recycling and recycle of functional rubber material. |
PDF Full Text Request