Mechanical properties, CaCO composites

Ma,C.G. Mai, Y.L. Rong, M.Z. Ruan, W.H. Zhang M.Q. (2007). Phase structure and mechanical properties of ternary polypropylene/elastomer/nano-CaCOs composites. Composites Science and Technology, vol.67, No.l4, pp.2997-3005, ISSN ... 

The pre-treatment of a filler surface changes fhe interface, and thus it is expected to affect the properties of adjacent phases extending some way into the bulk. There are examples of using the various surface modifiers such are acids and acid precursors, alkoxysilanes, organofitanates and related compounds, stearic acid and others." How the surface pre-treatment of CaCOs filler by sodium stearate changed fhe adhesion parameters in the PVAc composite is illustrated in Table 1 The adhesion parameters could be used to relate the interactions at the interface to the mechanical properties of the composite. For example, the small absolute decreases in the work of adhesion after the pre-treatment can lead to the proportionate large absolute decreases in fracture energy. 

Zhou and co-workers [27] studied the effect of surface treatment of calcium carbonate with sulfonated PEEK on the mechanical properties of the polymer. Tests used included tensile tests, flexural tests, notched Izod impact tests, TGA, DSC and SEM. The modulus and yield stress of the composites increased with CaCOs particle loading. This increase was attributed to the bonding between the particles and the PEEK matrix, was proved by the SEM of the tensile fracture surface of the composites. The treated fillers were found to give a better combination of properties, which indicated that the sulfonated PEEK played a constructive role in the calcium carbonate/PEEK composites. 

Recently, PVDF has been intensively studied by many authors as a polymer matrix for ceramic nanopowders such as BaTiOs [212,214-216], PbTiOs [217], CaCOs [218], and Pb(Zro.5TiOo.5)03 [215] because they combine the excellent ferroelectric properties of ceramics with the flexible mechanical properties of the polymer. The PVDF polymer composites with electroactive ceramic nanoparticles were prepared by sol-gel processes [214,217], a natural adsorption action between the nanosized BaTiOs and PVDF particles, and then a hot press process [216]. 

Weon J-I and Sue H-J (2006) Mechanical properties of talc- and CaCOs-reinforced high-crystallinity polypropylene composites, J Mater Sci 41 2291-2300. 

Most thermoplastics degrade rapidly when used outdoors because of photooxidation promoted by ultraviolet (UV) irradiation. A recent study on natural weathering of micro-CaCOs filled PP showed that the composites filled with surface treated CaC03 provided better retention of mechanical properties than those filled with untreated fillers, which demonstrated the importance of interfacial properties.Weathering behaviors of nano-CaC03 filled polymers have not been reported, and a study on this topic would be useful for exploring applications of the nanocomposites. 

Mechanical properties of commercial PP-CacOs composites ° are averaged suppliers data the vertical bars indicate the standard deviations shaded diamonds are data from one single manufacturer shaded triangles are data from B. Haworth, C.L. Raymond. Proceedings Eurofillers 97, Manchester, UK, Sept. 8-11,251-254,1997 the curves in the left part have been calculated with the Guth and Gold equation. 

In this chapter, the study carried out on nanofillers reinforced natural/synthetic rubber has been discussed. After a description on the NR rubber and CaCOs as filler, the development of synthetic composites with the incorporation of micro and nano-CaC03 as a filler material has also been discussed for comparative study. In particular, the role of fillers on the property modification of rubber properties, such as surface properties, mechanical strength, thermal conductivity, and permittivity has been mentioned. The effectiveness of this coating was demonstrated. The importance of well-dispersed nanoparticles on the improvement of the mechanical and electrical properties of polymers is also emphasized. However, one of the problems encountered is that the nanoparticles agglomerate easily because of their high surface energy. 

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