Fillers reinforcing activity

Conventionally fillers are divided into reinforcing, active, and inert ones. The reinforcing class includes mainly fibrous materials. Disperse fillers may also perform the reinforcing function, and then they are called active. For the criterion of activity of a filler it has been proposed to employ, for example, the extent of variation of the relative viscosity of the melt or solution caused by introduction of a filler [23] — the greater the variation the better the affinity between the polymer and the filler. 

Fillers are solid materials that are dispersed in plastics and elastomers. One distinguishes between inactive fillers that are used in the first place to make the plastics less expensive and active fillers (reinforcing fillers) that improve specific mechanical properties and thus effect a reinforcement . With the aid of these fillers, the elastic modulus, hardness, and thermostability are enhanced predominantly, whereas the impact strength of thermoplastic niaterials is re-... 

The main function of metal deactivators (MD) is to retard efficiently metal-catalyzed oxidation of polymers. Polymer contact with metals occur widely, for example, when certain fillers, reinforcements, and pigments are added to polymers, and, more importantly when polymers, such as polyolefins and PVC, are used as insulation materials for copper wires and power cables (copper is a pro-oxidant since it accelerates the decomposition of hydroperoxides to free radicals, which initiate polymer oxidation). The deactivators are normally poly functional chelating compounds with ligands containing atoms like N, O, S, and P (e.g., see Table 1, AOs 33 and 34) that can chelate with metals and decrease their catalytic activity. Depending on their chemical structures, many metal deactivators also function by other antioxidant mechanisms, e.g., AO 33 contains the hindered phenol moiety and would also function as CB-D antioxidants. 

Applications. Bound rubber is a measure of filler surface activity to the matrix, and it is considered as a factor in the estimation of filler reinforcement. 

A. What are the parameters of filler structure we have to account as responsible for reinforcing activity of different types of fillers ... 

The particle size of the filler as discussed earlier may be considered as a physical contribution to reinforcement, while filler surface activity provides the chemical contribution. The ability of the filler to react with the polymer results in chemical bonding, which increases strength significantly. In the absence of strong coupling bonds, the polymer is physically absorbed on the surface of the... 

In their activity, stabilizers normally are consumed other losses may occur through migration into elastomer inclusions or to the surface as well as through fixation to filler/reinforcement surfaces (adsorption). Under low loading levels, chemical aging will definitely determine the lifetime of a PP part. Not only does it create discolorations and aesthetic failure of the surface, but also cracks are induced which increase the stress sensitivity dramatically. 

Classifications of Fillers for Plastomers According to Their Reinforcement Activity... 

Classifying fillers with respect to fabrication process and reinforcing activity. 

In general, the reinforcing activity of a filler depends on at least four criteria ... 

The metal fillers act as a reinforcing material that results in added strength and stiffness (126). They color the plastic gray for nickel, 2inc, stainless steel, and aluminum, and brown for copper. Metal additives are more expensive than carbon black or surface-active agents, but they get extensive use in EMI shielding appHcations. 

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