Filler loading calcium carbonate

In most, but not all, cases the incorporation of mineral fillers at the levels needed to produce useful effects causes a significant decrease in the toughness or impact strength of the composite. The major exception is in polypropylene, where certain types of calcium carbonate can give a very significant increase in toughness at loadings of 30-40 wt% [33]. 

Several studies have considered the influence of filler type, size, concentration and geometry on shear yielding in highly loaded polymer melts. For example, the dynamic viscosity of polyethylene containing glass spheres, barium sulfate and calcium carbonate of various particle sizes was reported by Kambe and Takano [46]. Viscosity at very low frequencies was found to be sensitive to the network structure formed by the particles, and increased with filler concentration and decreasing particle size. However, the effects observed were dependent on the nature of the filler and its interaction with the polymer melt. 

More recently, Lin and Masuda [47] measured the viscoelastic properties of polypropylene melts filled with small (0.15 pm) and larger (4.0 pm) calcium carbonate particles. The dynamic modulus and viscosity were found to rise with filler loading especially at low frequencies. With highly filled compositions (at... 

Fig. 12. The frequency dependence of dynamic storage modulus G at 200 °C for calcium carbonate filled polypropylenes (mean particle size 0.15 pm).Filler loading wt%, (o) 0 (6) 10 (o) 20 (9) 30 [47]...

The observation that acid hydrolysis is avoided by fabrication of paper which is neutral or slightly alkaline has led to the incorporation of an alkaline filler such as calcium carbonate. Some very old papers which contained calcium carbonate as a loading material or as residues from processing of the fiber stock have shown excellent stability. 

Calcium carbonate fillers are either of ground limestone type or precipitated chalk type. They are inexpensive and have low oil-absorption, which allows considerable freedom in filler levels while keeping the viscosity under control. Relatively coarse particle size fillers ranging from 30 to 100 mesh are used to incorporate high loadings. 

Typical concentration range general range - 20-50 wt% with some fillers mechanical properties decrease even at low loadings (10%) calcium carbonate - 10-60 wt%, kaolin - 20-40 wt% talc - 20-40 wt% glass beads - 20-50 vol% " carbon black - 10-30 wt% glass fiber - 1-60 01% ° magnesium hydroxide - 60-65 wt% (for V-0 classification) antimony trioxide - 10 wt% (for V-0 classification)... 

The addition of aluminum trihydrate improved fire resistance of glass epoxy laminates but, because of the high loading required, it decreased the mechanical properties of the laminate. Various components of formulation were studied to improve performance. It was found that the curing agent and impact modifier help to improve the mechanical properties of the laminates. Other fillers were also studied in order to understand the impact of filler on properties. It was found that all fillers (glass beads, quartz, calcium carbonate, mica) reduce mechanical properties of laminates, not just aluminum trihydrate. " Aluminum trihydrate was found to be one of better performers in this system. 

The principal components of ash are calcium carbonate— in the form of precipitated calcium carbonate (PCC) or ground calcium carbonate (GCC)—that typically constitutes 20% and up to 75% of dry sludge content, and clay. These two minerals are typically loaded into paper as a coating and filler to improve the mechanical characteristics as well as the appearance of paper. The resulting papermaking sludge, particularly mixed office paper sludge, consists primarily of two major components, that is, fiber and minerals finely mixed with each other. 

Extrudate Swell The extrudate swell of wood-filled plastics typically increases with the flow rate (shear rate), decreases with filler loading, and practically does not depend on the melt temperature. A nonfibrous filler, such as calcium carbonate, also suppresses swell of polyethylene, and in the case of medium-density polyethylene, a swell suppression was maximal at 30% of calcium carbonate (0.4 (xm particles) [32]. A similar effect was shown using HDPE filled with rice hulls (Table 17.13). 

Camel-FIL. [Genstar Sttme Prods.] Calcium carbonate filler for hi loadings in glass-reinforced polyester, in PVC, FP, rubber automotive goods and floor dies, caulks, sealants, and adhesives. 

A representative selection of commercial color concentrates (Colortech Inc, Brampton, ON) were used for this study. Each pelletized sample consisted of a blend of organic and inorganic pigments dispersed in Linear Low Density Polyethylene (LLDPE) carrier resin. Pigment loading varied between 3,6 and 50.0 wt,% and some formulations contained up to 33.1 wt.% calcium carbonate filler. All were prepared on a production-scale 40 Liter Gelimat-style... 

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