Carbon black is widely used as an active filler in the rubber industry to improve the physical properties of rubber. The surface energy of carbon black is high compared to that of various elastomers like styrene-butadiene rubber (SBR), butadiene rubber (BR) and ethylene-propylene-diene rubber (EPDM). The work aims at reducing the surface energy of carbon black by modifying its surface for application especially in rubber blends. The present paper looks into the possibility of using plasma polymerisation of acetylene as a surface modification technique for carbon black in comparison with silica. Thermogravimetric analysis, wetting behaviour with various liquids of known surface tension and time of flight secondary ion mass spectrometry (ToF-SIMS) were used to characterise the carbon black before and after surface modification. The study shows that surface modification of carbon black by plasma polymerisation is difficult in comparison with silica, unless treated for long duration. The mechanistic aspects of the surface modification and the importance of active sites on the carbon black surface for effective modification are discussed in the paper.

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Carbon black and silica are widely used active fillers in the rubber industry to improve the physical and dynamic properties of rubbers. The surface energy difference between rubbers and these active fillers is large, which has a negative influence on the stability of their dispersion in the rubber matrix and on the distribution in blends of different rubbers. Reduction of the surface energy of carbon black and silica is aimed for by modifying their surfaces. Plasma polymerization is utilized to modify the surface of carbon black and silica by depositing a thin film over its surface. The modified fillers are characterized using thermogravimetric analysis (TGA), x-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). The studies show that carbon black and silica behave differently towards surface modification by plasma polymerization. The difference in behavior of carbon black and silica is related to the availability of active sites on their surface during exposure to the plasma atmosphere. In this paper the mechanistic aspects of surface modification by plasma polymerization are also discussed.

Surface modification of carbon black by plasma polymerization was aimed to reduce its surface energy in order to compatibilize the filler with various elastomers. A fullerenic carbon black was used for the modification process. Thermogravimetric analysis, wetting behavior with liquids of known surface tension, TEM and TOF‐SIMS were used to characterize the carbon black before and after modification. The state of plasma‐coated carbon black in rubber was studied by means of conductivity measurements. The behavior of the modified filler in rubber was studied using the Payne effect and stress/strain properties. The study shows that plasma‐coated carbon black results in a better dispersion in different rubber systems than the uncoated version. magnified image

Aim: In the present era of relationship-based care, effective communication between practitioners and patients vastly affects treatment planning and ultimately patient satisfaction.This study compared the communication skills of two groups of final year's undergraduate dental students with and without prior training in effective communication. Methodology: Eighty final year student were asked to participate in the study. Participants were randomly divided into two groups of forty each. One group received training in history taking and effective communication with patients, through a course that spanned across three hours. The remaining forty were not put through the course. Subsequently all the eighty students were asked to examine one patient each and record patient case history. The communication skills of the students were evaluated by the patients in the form of a feedback questionnaire provided to them after the dental examination. Results: The results indicated that students who had received training in communication skills were rated significantly higher than the untrained student in all aspects of communication Conclusion: Proper training improved communication skills significantly among dental students