Calcium carbonate and other additives

The particle size (0.07-1.9 pm) has no influence on the thermal composite s properties, and also the particle content does not affect the melting temperature or the crystallinity of PP. Surface treatment of the particles by the stearic acid coating showed an important positive effect on the impact strength due to the improved dispersion of the CaC03 particles. In addition PP molecular weight should be considered when designing a CaC03-PP nanocomposite 

Carbon additives are used in polymer composites as fillers, reinforcing agents and pigments. In addition, carbon black is used to enhance UV stability, electrical conductivity and weather resistance. PP geotextiles containing carbon black are applied for soil reinforcement, filtration and other construction 

The effect of carbon black on thermal and photo-oxidative degradation of oriented PP geotextile tapes was studied by Horrocks et a/. The influence of particle size (16-60mn), stmcture, aggregate shape, specific surface volatile content and concentration was determined. Significant increases in thermal stabilities were observed when increasing carbon black content in PP composite. 

However, the opposite effect of the carbon black with highest volatile content on thermal stability was observed. This phenomenon is attributed to the adsorption of antioxidant by the carbon black surface or to the sensitization of thermal oxidative reactions by the surface oxygenated groups present. It has been proved that different behaviour is related to the volatile content, due to the presence of carboxylic and sulphonic acid groups. Not only are the temperature and rate of decomposition influenced by embedded carbon black particles, but also the decomposition products. The presence of 1-alkene oligomers with 3n C atoms is reduced, while 2-alkenes and 1-alkenes with 3n+l C atoms are increased. Carbon black promotes chain scission and participates in the radical transfer reactions. Incorporated particles of carbon black, especially those with small particle size, improve UV durability.  

Fu et first prepared octamethyl-POSS/PP composites by melt blending and studied their crystallisation behaviour. Fina et al. investigated 

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