Properties fillers

The properties of fillers which induence a given end use are many. The overall value of a filler is a complex function of intrinsic material characteristics, eg, tme density, melting point, crystal habit, and chemical composition and of process-dependent factors, eg, particle-si2e distribution, surface chemistry, purity, and bulk density. Fillers impart performance or economic value to the compositions of which they are part. These values, often called functional properties, vary according to the nature of the appHcation. A quantification of the functional properties per unit cost in many cases provides a vaUd criterion for filler comparison and selection. The following are summaries of key filler properties and values. 

Hardness. The hardness (qv), or related property abrasiveness, is an important filler property. Hardness is determined by comparison to materials of known hardness on the Mohs scale. On this nonlinear scale, diamond is rated 10, quartz 7, calcite 3, and talc 1. The abrasiveness of a filler is also dependent on psd and the presence of impurities, eg, ka olin clay (Mohs hardness of 3) can be quite abrasive because of the presence of quartz impurities. 

S.J.Lowell, Desensitized Torpex-Type Bomb Fillers, Properties of , PATR 2355 (1956) (Conf)... 

It follows that, when formulating a manufacturing composition for a syntactic foam, all of the binder and filler properties, as well as the process parameters have to be taken into account. Special computer methods have been proposed for selecting the best formulations whilst accounting for economic efficiency82... 

We have outlined the product performance characteristics of fillers. This leads us to an identification of filler properties which allow different fillers to be compared and evaluated. When we go on to develop a definition of fillers in Section 1.3, this list will help to make the definition inclusive yet precise. It will also assist in the classification of fillers discussed in Section 1.4. 

We have outlined factors which affect particle distribution in a matrix. This distribution depends partly on filler properties but predominantly on the combination of properties of the pair filler-matrix. Filler distribution in a matrix depends on intended application. Some, such as applications which use fillers for reinforcement, require a homogeneous distribution of particles. In others, such as mentioned above electrical conductive materials, adhesives), a uniform distribution of filler particles may decrease their effectiveness. 

Figure 7.37 shows the effect of the percolation threshold on a material s conductivity. In this example the material has s = 7.75 which is a very high value compared with other data found in the literature. The value of s depends on the structure and surface area of the filler used for production of the material. The filler properties determine the interface formation which permit the electron tunneling mechanism to occur. 

One function of a coupling agent is to interact with filler. It is thus proven a priori that coupling agents affect filler properties, and modified fillers affect the system. Numerous works use this modification. In this discussion, we summarize the effects obtained. Table 13.1 contains this summary. 

In the cosmetics industry, finely dispersed fillers, are used as abrasives (toothpaste, scrub cosmetics), for their light reflecting properties (sunscreen lotions), for their dehydrating and astringent effect (kaolin in face masks), for their cooling effect (zinc oxide in sunburn lotion), and as cosmetic color additives and extenders (makeup). The many different applications require an extensive range of filler properties. 

The chemoviscosity of thermosetting resins is affected by many variables. In a major review, Ryan 1984) expressed the chemoviscosity (rj) as a function of pressure (P), temperature, time, shear rate (y ) and filler properties (F), as shown by the following general equation ... 

Uses Filler for lacquer systems Features Hydrophobic functional filler Properties Lt. colored powd. dens. 2.6 g/cm bulk dens. 0.4 g/cm Albacar 5970 [Specialty Mins.]... 

Featiffes Brilliant grn.-shade blue exc. lighifasiness not bleachable in hypochlorite very good affinity for clay fillers Properties Liq. dens. 9.5 Ib/gal vise. < 100 cps pH 9.5 Ponolith Fast Black P Liq. [ yer/lndustrial Chems.J Chem. Descrip. Carbon black disp. 

Features Neutral-shade red partially bleachable in hypochlorite very good lightfastness very good affinity for CaCOs, clay, and TiOj fillers Properties Liq. dens. 8.8 Ib/gal vise. 1500 cps pH 10.5... 

Features Not rec. for laminates exc. bleedfastness not bleachable in hypochlorite very good affinity for TiOj fillers Properties BIk. liq. disp. 

Uses Dye for beater applic. to acid-sized papers, esp. where high lightfastness is required colorant for coatings and deco printing inks Features Not rec. for laminates exc. bleedfastness completely bleachable in hypochlorite exc. affinity for TiOj fillers very good affinity for clay and CaCOs fillers Properties Yel. liq. disp. 

Features Brilliant rec. for tinting and for producing deeper shades partially bleachable in hypochlorite good lightfastness very good affinity for clay fillers good affinity for TiOj and CaCOj fillers Properties Green-shade yel. liq. disp. dens. 8.7 Ib/gal vise. < 100 cps pH 8.0... 

Chem. Descrip. Methacryllc acid copolymer Uses Thickener for emulsion paints and fillers Properties Powd. sol. in water (pH > 8) acid no. 405-440 Rohagum M-335 [Rohm Am. Rohm GmbH]... 

Uses Associative thickener, rheology control agent, vise, builder, stabilizer for aq. systems for indoor and outdoor paints, latex and anticorrosive paints, syn. resin-bound renderings, adhesives, and paste fillers Properties Wh. lightly transparent liq. emulsion disp. in water dens. 1.06 g/ml (20 C) pH = 6.5 nonionic 40% act. in water/butyltriglycol (40/ 20)... 

The subject of filler reinforcement of rubbers has been an area of interest to the rubber industry for more than a century. Various models had been proposed in the past to explain the filler reinforcement in vulcanized rubber. The use of modern finite element analysis (FEA) and various mathematical models have made further progress to understand the mechanisms of reinforcement in filled vulcanized rubber. But this does not imply that a complete understanding of the subject has been achieved. The detailed effects of filler properties such as surface area and shape on the filler reinforcement are still not completely understood. A detailed understanding of the filler reinforcement should provide an insight into the increase in modulus and strength. 

Finite elements analysis has shown that filler properties such as surface area, shape and structure have strong infiuence on the filler reinforcement and filler rubber properties. Another approach to understand the filler network and the filler-rubber interactions more closely is to study the electrical and mechanical behaviour of the filled elastomer under strain for various different conditions. Jha et have investigated the effect of surface area and structure of filler... 

Primary filler properties controlling the morphology and properties of plastic products are geometry, concentration, density, modulus, strength, and surface chemistry. Additional filler properties related to processing (compounding and shaping) are as follows ... 

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