| Carbon nanotubes(CNTs),as one-dimensional nanomaterials,have excellent properties that make them one of the most promising carbon materials.In order to improve the overall performance of rubber products,many studies have used CNTs as a reinforcing material to fill in rubber,but due to their high specific surface area and large aspect ratio,CNTs are prone to agglomeration,and their excellent properties cannot be fully utilised in rubber.How to make CNTs uniformly dispersed in the rubber matrix and enhance the interfacial bonding ability between CNTs and the rubber matrix is a challenge that needs to be solved.In order to achieve the uniform dispersion of CNTs in rubber composites,this paper presents a mechanism and experimental study on the preparation of carbon nanotube rubber composites based on wet blending;the effects of CNTs modified by ozone,potassium permalate and graphene oxide(GO)on the properties of rubber composites are investigated;a new method of carbon black carbon tubes combining dispersion flocculation by dry ice expansion blasting and shear solidification is proposed.The new wet mixing method of masterbatch method is proposed to promote the dispersion effect of CNTs in rubber composites,shorten the drying time and improve the efficiency of masterbatch preparation.The main work accomplished in this thesis is as follows:(1)The preparation mechanism of carbon nanotube rubber composites based on wet blending was investigated.The activation mechanism of CNTs surface treated with ozone,potassium perchlorate and graphene oxide was analyzed,and a technical picture of the dry ice assisted CNTs/CB/NR blend total condensation process was constructed to explore the mechanism of modified CNTs reinforced rubber composites and to achieve uniform dispersion of CNTs in rubber composites.(2)A new method for wet blending of carbon nanotubes/carbon black masterbatch by combining dry ice swelling blast dispersion flocculation and shear solidification was proposed.The effect of dry ice on the flocculation process of CNTs/CB/NR blends was analyzed,the inner law of the difference between the blending process and the performance of the rubber was investigated,and the optimal preparation parameters of the wet blending process of carbon nanotubes/carbon black masterbatch were explored.(3)Systematic experimental studies on the preparation of two master glues,the carbon tube master glue method and the carbon tube carbon black master glue method,were carried out:(1)The effects of different types and numbers of carbon nanotubes on the properties of CNTs/NR composites were investigated.The experimental results showed that for different types of CNTs,the CNTs with the smaller length-to-diameter ratio and moderate specific surface area,type GT-400,had the best properties;for different amounts of CNTs,the best physical and mechanical properties were obtained when 3phr CNTs were added,and as the number of CNTs increased,the dispersion of CNTs became worse and the mechanical properties gradually decreased,while the best electrical conductivity was obtained when 5 phr CNTs were added.The best electrical conductivity was obtained when 5phr CNTs were added.(2)To investigate the effect of days of ozone modification of CNTs on the properties of prepared CNTs/CB/NR rubber composites.The experimental results showed that the ozone oxidation modified CNTs could increase the hydroxyl content on the surface of CNTs and enhance the surface activity,which was conducive to the good dispersion of CNTs in NR.When the ozone treatment was carried out for 3 days,the best overall performance of the rubber was obtained,including tensile strength of 26.51 MPa,DIN abrasion of 0.1243 cm~3,rolling resistance of 0.1270 and electrical conductivity of1.52×10~6.(3)The effect of the degree of oxidation of CNTs by potassium permalate in neutral and acidic environments on the properties of the prepared CNTs/CB/NR rubber composites was investigated.The experimental results showed that the hydroxyl content on the surface of CNTs increased after the treatment of CNTs with potassium permalate,and the hydroxyl content increased as the degree of oxidation increased.When CNTs were treated with potassium permalate in an acidic environment,the best overall performance of the rubber was obtained,including tensile strength of 27.21 MPa,DIN abrasion of 0.1279 cm~3,rolling resistance of 0.1392 and electrical conductivity of 5.59×10~5.(4)To investigate the effect of the amount of GO on the properties of the prepared CNTs/CB/NR rubber composites.The experimental results show that the addition of GO can form a one-dimensional and two-dimensional interpenetrating network structure with CNTs,which can attenuate the agglomeration of CNTs themselves to a certain extent.When 1phr of GO was added,the overall performance of the rubber was best,including tensile strength of 27.74MPa,DIN wear of 0.1282cm~3,rolling resistance of0.1344 and electrical conductivity of 1.64×10~6.(5)The effect of different blending methods on the properties of prepared CNTs/CB/NR composites was investigated.The properties of the rubber composites prepared by three mixing methods,namely the carbon tube masterbatch method,the carbon tube carbon black masterbatch method and the traditional dry method,were compared.The experimental results show that the two wet blending processes are better than the traditional dry process,and the best overall performance of the designed new wet blending process,carbon tube carbon black masterbatch method,is the best,including tensile strength of 24.86 MPa,DIN abrasion of 0.1341 cm~3,rolling resistance of 0.1433 and electrical conductivity of 1.44×10~7.The CNTs/CB/NR composites with excellent properties were prepared by a wet blending process combining dry ice assisted dispersion flocculation and shear solidification after modification of CNTs,which enables the homogeneous dispersion of CNTs in the rubber matrix.This method provides a new solution for the application of CNTs,an efficient reinforcing material,in natural rubber systems. |
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