Effect Of Ionic Liquid Modified Carbon Nanotubes On Properties Of NBR Nanocomposites

Because carbon nanotubes have a relatively large aspect ratio,specific surface area,and large surface energy,the carbon nanotubes are prone to entanglement and agglomeration.So their applications in rubber are hindered.The problem of modification of carbon nanotubes has become a more important issue nowadays.Based on the excellent properties of carbon nanotubes and ionic liquids,imidazole-based ionic liquids were used to form?-?interactions with the outer wall of carbon nanotubes through non-covalent bond modification in this paper.The modified carbon nanotube(IL-MWCNT)with good dispersibility was prepared.Then the prepared modified carbon nanotubes were mixed with nitrile rubber(NBR)and nitrile latex(NBRL)by solid phase dispersion and liquid phase dispersion respectively to obtain IL-MWCNT/NBR and IL-MWCNT/NBRL composites.The carbon nanotubes modified by ionic liquids were tested by raman spectrometer(Raman),thermo gravimetric analyzer(TGA)and other instruments;The dispersion of carbon nanotubes in rubber by means of scanning electron microscope(SEM),rubber processing analyzer(RPA),dynamic mechanics analyzer(DMA),as well as the mechanical properties,vulcanization properties,dynamic mechanical properties of the rubber composites were deeply studied.The results of the study are as follows:(1)The carbon nanotubes were modified with ionic liquids.And the original structure of carbon nanotubes were not destroyed.The TEM observation showed that the entanglement of carbon nanotubes in water was obviously unfolded,and the state of dispersion was uniform in water.By TGA,it showed that the interaction between carbon nanotubes and ionic liquids could form a stable suspension in water.So the carbon nanotubes could exist stably and uniformly in water.(2)The ionic liquid modified carbon nanotubes were blended with nitrile rubber and nitrile latex.By scanning electron microscope,the agglomeration of the composites was significantly reduced compared with that of the unmodified carbon nanotubes.The mechanical properties of IL-MWCNT/NBR and IL-MWCNT/NBRL composites were tested,and the tensile and tear properties of the composites were improved after ionic liquid modification;The t₁₀ decreased with the increase of ionic liquid content.The ionic liquid modified carbon nanotubes were blended with nitrile rubber and nitrile latex.By scanning electron microscope,the agglomeration of the composites was significantly reduced compared with that of the unmodified carbon nanotubes.The mechanical properties of IL-MWCNT/NBR and IL-MWCNT/NBRL composites were tested,and the tensile and tear properties of the composites were improved after ionic liquid modification.At the same time,the t₉₀ also began to decrease.Because the modified carbon nanotubes could be dispersed uniformly in rubber quickly,it increased the heat transfer of the composite and thus made the vulcanization rate faster.The rubber processing and dynamic mechanical properties were tested by RPA,DMA.Compared with ionic liquid modified IL-MWCNT/NBR and IL-MWCNT/NBRL composites and unmodified rubber composites,the?G'became smaller,indicating that the interaction between carbon nanotubes became smaller.The carbon nanotubes could be dispersed more evenly in rubber,and the interfacial force between carbon nanotubes and rubber increased.The glass transition temperature decreased and the cold resistance of rubber composites increased.The experimental data showed that when 3 phr of ionic liquids were added to modify the carbon nanotubes,the reinforcement effect was the best.(3)The results showed that the dispersion uniformity of IL-MWCNT in the IL-MWCNT/NBRL was better than that of the IL-MWCNT/NBR composites,and the reinforcement effect of IL-MWCNT on the IL-MWCNT/NBRL composites was better than the IL-MWCNT/NBR composites.