Papers by Author: Jun Ping Song

Abstract: Eight kinds of carbon black filled natural rubber composites were prepared, and thermal conductivity was studied. Acetylene black contributes much to the thermal conductivity of rubber, and tiny loading results in considerable improvement. The conductive carbon black 40B2 is advantageous for the improvement in thermal conductivity of rubber when its loading reaches middle level, and at its middle level, also tiny loading results in much improvement. Most kinds of carbon black for rubber application filled rubber composites have good properties except for N134 and N660, especially the poor contribution of N660. Additionally, in the case of carbon black filled rubber composites, addition of filler may not necessarily benefit the thermal conductivity when filler loading is not much.

Abstract: Graphitized carbon black 40b2 and acetylene black were filled separately in natural rubber matrix for preparing vulcanized rubber. The thermal conductivity of both kinds of composites was studied considering filler loading and temperature. SEM and TEM were applied to observe morphology of the filler and composites. The experimental results show that thermal conductivity of acetylene black/rubber composites is much better than that of graphitized carbon black 40b2/rubber composites, which is opposite to the electric conduction properties. As filler loading increased, the difference increased, and when the filler loading is up to 40phr, the thermal conductivity value of acetylene black/rubber composite is 53% larger than the other one. TEM shows that acetylene black has more botryoidal structure, larger carbon black aggregates in size, and much looser surface than 40b2.Moreover, for acetylene black, particles contact by surface mainly, and for 40b2, particles contact by point mainly. SEM shows that the distribution of carbon black 40b2 in rubber matrix is much better than acetylene black. The better thermal conductivity for acetylene black is attributed to the higher structure, nonuniform distribution in rubber matrix and surface contact between particles.

Abstract: A kind of graphitized carbon black 40B2 was incorporated in natural rubber matrix and vulcanizates were prepared. The content of carbon black varied from 4 to 100phr for 100phr of natural rubber. Thermal conductivity of the CB/rubber composites was studied as a function of CB loadings and temperature. TEM and SEM were employed to explore the morphology of the carbon black and the composites. It was found that percolation phenomenon existed in thermal conductivity of CB/rubber composites at different filler loadings, which was much similar with percolation behavior in electrical conductivity properties of many composites, and the percolation threshold was about 13.63%. The influence of temperature on thermal conductivity was more obviously within the region from the percolation threshold to the volume fraction of 26.2%.However, no great effect could be found on the percolation behavior of the composites in thermal conductivity. The result of TEM indicated that the mean size of CB particles was about 25nm, the maximum size of CB aggregates was about 125nm, and the CB aggregates were multichain in shape. The results of SEM showed that the distribution of CB differed at different filler loadings. Before the percolation threshold, the CB aggregates existed isolatedly, nevertheless at the percolation threshold, some long chains made up of CB aggregates ran through the rubber matrix, which resulted in the rapid increase in thermal conductivity value, and then with the addition of CB loadings, the number of chains increased. When the volume fraction was up to 26.2%, some three dimensional networks formed.

Abstract: Five kinds of carbon black filled natural rubber were prepared, and thermal conductivity was studied considering two factors, which include temperature and volume percent of the filler. It was found that thermal conductivity had relevance to temperature and volume percent of carbon black, besides, structure and specific area of carbon black were also very important influencing factors. Moreover, reuniting phenomenon of nanometer grade of carbon black has much effect on thermal conductivity.

Abstract: Through measuring the thermal conductivities and tensile strength of nature rubbers filled with carbon black and comparing with each other, it is shown that the difference of carbon black particle size and the structure affects on the thermal conductivity and tensile strength of nature rubber. Thermal conductivities of carbon black-filled nature rubber are enhanced with the increase of volume fraction of filler; tensile strength of composite increases first and then decreases with the increase of carbon black volume fraction.