Mineral Fillers Carboxylic Acid-Polymer

There is a large literature on the influence of additives on particle-filled elastomers and thermoplastics. Many particle-additive systems are marketed to produce polymer compounds containing small particles, which have strong interparticle forces. Small molecule additives are used in compounds with very small polar particles. Larger particles (i.e., particles greater in size than 5 pm) generally do not require associated additives because their flow behavior is dominated by hydrodynamic factors as described in Section 2.3. Some small nonpolar particles do not have suitable additives. Carbon black has relatively weak interparticle forces (Section 2.4.3), and additives have not been found to significantly modify the flow and mechanical characteristics of its compounds. 

Most of these studies did not develop deeply into the mechanisms that occur in these ternary systems. It is, however, clear that two different types of phenomena occur. Ahn and White [6,7] 

7 Polymer-FiUer-Additives and Curative-Accelerator Compounds 

Surface treatment of caldte with stearic acid significantly reduces the viscosities and yield values of molten polymer compounds [4,5]. Small CaCOj particles are commercially treated with stearic add to improve their processability. Suetsugu and White [5] have investigated stearic acid effects on a calcite-filled system. They found an increasing order of reduction with decreasing particle size and decreasing shear rate. K. J. Kim and White studied the effect of stearic add on caldte and on talc particles in a polypropylene (PP) matrix [9 to 11 ]. 

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