Filler density

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. 

Table . HOPE209-01-based Keroplast density, filler-Kerogene70, 20% (vol. content) at different regimes of pelleting and extrusion...

Revision A of this specification was published 10 March 1957. There are two types. Type I for 4,5000 psig hydrostatic pressure and Type II for 10,000 psig. The QPL was cancelled on 31 March 1986. The syntactic buoyancy material consists of a low-density filler such as hollow-glass microspheres in a resin matrix such as epoxy resin. 

In many compounding operations it is necessary to split the feed streams. This may be required in order to 1) achieve disperse phase size of an impact modifier 2) retain aspect ratio of reinforcing fiber filler or 3) obtain high level of loading for either low bulk density filler or incompatible low viscosity additives. 

Since fillers are bought by the pound and many finished goods sold by the yard, it is important to use pound volume figures when using a high-density filler for cost reduction purposes. 

Plastic (density) Filler Content of the filler, (% w/w) Specific gravity of the filled plastic, calculated (g/cm3)... 

Dualite. [Pierce Stevens] Hollow composite microspheres with PVDC/ acrylonitrile cc lymer shell and calcium carbonate coating low density filler f( use in plastics, coatings, adhesives, BMC SMC rubber conpding., piper mfg. 

SBS or SEBS has been used as an impact modifier in PPE/PA blends, with PA usually being the matrix, and PPE an organic, low density filler. The blends were developed in the early 1970 s by the Asahi Chemical. By the end of the decade the first reactive blends were announced by the Sumitomo Chemical [Ueno and Maruyama, 1981] and General Electric [Van der Meer et al., 1989]. 

To enhanced rigidity of PO, 5-35 wt% of modified PPE was added. In this application PPE can be considered a low density filler. Similar effects can be obtained adding a small quantity of other polymers, viz. PC, POM, PPS, etc. 

The reactive methods of compatibili2ation developed subsequently allowed the second generation Noryl (a blend of PPO with PA) to be developed. The compositions claimed usually cover 30-70% of each of the main ingredients, PPO and PA, with additionally up to four parts of such modifier as polycarboxylic acid, trimellitic anhydride acid chloride, quinine, oxidized polyolefin wax, and so on. In most cases, PA forms a matrix with spherical inclusions of PPO acting as compatibilized low-density filler. 

Uses Blowing agent in printing inks, PU, PVC plastisols, fabrics, paper expanded microspheres as ultra-low density fillers for use in engineered prods, in which other fillers would not be suitable, e.g., syn. marble and wood, coatings, sealants, explosives, auto, marine fillers, molding compds., composites, paint and crack fillers, cable fillings, elastomers Features Unexpanded microspheres Expancel 551 WE [Expancel]... 

Large volumes of air that are entrapped by the melt via low-density fillers have to be removed during compounding. 

The bulk density of mica also effects compounding rates. Higher bulk density mica products are wet out by resin much faster than low bulk density mica. This occurs because it is more difficult to remove adsorbed air from smaller particles in low bulk density fillers. 

Modification Modified filler density Filler weight fraction Composite density... 

There are other tests for polymers that are not included in this review including some density, filler analysis techniques and other physical tests. For convenience, a listing of ASTM and ISO standards for the major test in this work is provided in the references. 

It is appropriate to mention acoustic properties here, as they are affected by density. Adding filler usually increases the density compared to the host polymer, and this is usually an unwanted side effect. However, it is common to make sound deadening composites by using high-density fillers such as barium sulfate (BaS04, 4.5 g/cm ) or magnetite (Fe304, 5.1 g/cm ) [23]. 

Other Applications Other applications include foams, low density fillers for plastics and high-temperature thermal insulation. 

US velocity and attenuation measurements can also be used to determine solid-state material properties such as concentration and dispersion of fillers [908,909]. The active level of the acoustic emission signal of PP/talc composites was related to the degree of dispersion of the filler in the matrix [910]. LDPE/28-32 wt.% Mg(OH)2 and HDPE/0-10 wt.% Mg(OH)2 samples were examined over a wide range of temperatures (160-200°C) and pressures (up to 60 bar) to determine the effect of melt T, p and filler concentration on US velocity and attenuation in the melt [911]. Ultrasound velocity is affected by melt T, p and material density (filler content) US attenuation increases with increasing filler content. As US calculated filler concentrations deviated consistently from off-line TGA measured values (Fig. 1.43) it is obvious that further validation is required. In principle, extmsion processing data can be used to predict filler concentration. Accurate determination of filler concentration in real time is potentially useful to reduce excess and unnecessary usage of filler, to reduce scrap product and save production costs. 

---