| In this study,natural rubber latex was used as the main material. N330 carbon black,nano-CaCO3 and precipitated silica were choosed as fillers.Their dispersions and mixed emulsions which were made of natural rubber latex and filler dispersion were prepared with T25 high-speed disperser,ultrasonic oscillator and high pressure homogenizer.At the same time,the dispersion and agglomeration effects of the three dispersions and mixed emulsions which were made by the three methods, were studied by Laser Particle Size Distribution Analyzer,Phase Contrast microscope,Scanning Electron Microscope (SEM),Transmission Electronic Microscope (TEM) and so on; the properties of mother stocks were studied by Mooney Viscometer,TGA and RPA2000 Rubber Processing Analyzer,the mechanical properties of the three vulcanized rubber were characterized by Electronic pull machine.The results showed that:(1)The influences of time and rotor speed on the three kinds of nano-filler dispersions which were made with T25 high-speed disperser were obvious and different.With the extension of treatment time,the particle sizes of the three dispersions reduced and their distribution became narrower.The particle sizes became small after five minutes at the speed of 20000r/min. The nano-CaCO3 particle size was only 0.9um which was the smallest in the three kinds of dispersions, the particle size of carbon black and silica were both about 7um.Unlike silica,the dispersions of carbon black and nano-CaCO3 were stable and the settling amounts were little.With the rotor speed speeding up the particle size of nano- CaCO3 dispersion decreased,the silica dispersion reduced under high speed,while the particle size of cabon black dispersion first increased and then reduced.The agglomeration of the three fillers and latex particles in the latex emulsion dealded with by T25 high-speed dispersion machine could be achieved,but the effect was not obvious. The dispersion of the three fillers in the mother stock of the mixing latex treated under high-speed was better than before so was the tensile strength of vulcanizate rubber. (2)Take carbon black and CaCO3 for examples,the dispersion of particles in suspension and mixed nano-filler dispersion made by ultrasonic oscillator were studied,and the mechanical properties of rubber compounds were compared with those of the traditional mechanical mixing.The experimental results showed that the filler in the two kinds of dispersion had poor dispersion and serious settlement;the photos of SEM showed that after ultrasonic treatment the surface of latex particles were smooth and there were no nano-filler adsorpted on them.The dispersion of filler in mother stock and the mechanical properties of vulcanized was not obviously changed. This indicated that it was difficult to achieve the agglomeration between nano-filler and natural rubber latex and to improve the filler dispersion in rubber compound by the ultrasonic method.(3)The high-pressure homogenizer emulsion was used to prepare dispersion and mixed emulsion.The experiment results showed that the dispersion had small particle size,narrow distribution,good dispersion,little settling amount and stable storage.The tensile strength of mixed emulsion film became higher than the one before treatment.The mooney vicosity,modulus and the decomposition temperature in N2 of NR/nano-filler mother stocks were high,the dispersion of nano-fillers in mother stock was good.The mechanical properties of vulcanized rubber made by pressure agglomeration are better than that made by traditional mechenical mixing.The mechanical properties of vulcanized rubber were the best when the amount of carbon black was 20 and the amount of nano-CaCO3 was 5 as much as that of silica.
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