The Effect Of Preparation And Surface Modification Of Nanocellulose On Carbon Black Reinforced Natural Rubber Composites

Nanocellulose,a natural nanomaterial with high modulus and high aspect ratio,is the most abundant natural polymer in nature,and it is widely found in plants,marine organisms and microorganisms.Nanocellulose has dimensional stability,good rheological properties and processing properties and its high crystallinity gives nanocellulose the advantages of low density,high specific strength modulus and high specific strength.Therefore,nanocellulose is an ideal and green and environmentally friendly reinforcing filler,which has the potential to replace traditional fillers.Nanocellulose(NCC)was prepared by double oxidation method from softwood pulp,microcrystalline cellulose,cotton straw and bagasse.Then the different nanocellulose was applied to the reinforcement of natural rubber(NR).The morphology,particle size,crystal form,crystallinity and yield of different nanocelluloses,as well as the reinforcing effect on natural rubber,were compared to select the better nanocellulose for modification,aiming to further improve the dispersion state of cellulose in the rubber matrix.The results showed that the morphology,particle size,crystal form and crystallinity of nanocellulose prepared from different raw materials were slightly different,but the yield of nanocellulose prepared from softwood pulp was better.Therefore,cetyltrimethylammonium bromide(CTMAB),a cationic surfactant,was used to modify the nanocellulose prepared from softwood pulp,and the results showed that cetyltrimethylammonium bromide was successfully adsorbed on the surface of nanocellulose and the modification had little effect on crystallinity.The modified nanocrystalline cellulose(m-NCC)was used to reinforce natural rubber.In this composite architecture,it was found that when the filler content was 10 phr,the surface modification of NCC improved the dispersion state of NCC in the NR matrix and the interface interaction between NR and NCC.Therefore,the comprehensive performance of NR/m-NCC composite material was better than pure NR,and its tensile strength,elongation at break and tear strength was increased by 132.8,20,and 66.1%,respectively.In addition,composites filled m-NCC could shorten the vulcanization time of rubber and improve the high temperature aging resistance of NR composites.The cationic surfactant-modified nanocellulose was used to partially replace carbon black to reinforce natural rubber,focusing on the effect of cationic surfactants on the dispersion of nanocellulose in the rubber matrix and the effect of partially replacing carbon black with modified nanocellulose on the mechanical properties and aging properties of natural rubber.The results showed that the partial replacement of carbon black by NCC or m-NCC can shorten the vulcanization time of natural rubber composites.In addition,the surface modification of nanocellulose improved its dispersion in the natural rubber matrix and the filler-rubber interface interaction,and had little effect on the thermal stability of the NR composites.Besides,the modified nanocellulose partly replaced the carbon black reinforced natural rubber composite with a lower stress at 300% elongation,but the tensile strength,elongation at break,tear strength and wear resistance of the composites were significantly improved.After 72 h of hot air aging treatment at 70?,the tensile strength,stress at 300%elongation and tear strength of the natural rubber composites reinforced by m-NCC partly replaced carbon black had been further improved,but the elongation at break decreased.In addition,the heat built-up of the composites in which m-NCC partially replaced carbon black was increased,but the flex cracking resistance was improved.