Production and Characterization of Polyethylene/Calcium Carbonate
Composite Materials by Using Calcium Carbonate Dry and Wet
Coated With Different Fatty Acids
Ilhan Ozen, Suleyman Simsek, and Feride Eren
Erciyes University, Engineering Faculty, Textile Engineering Department, 38039 Kayseri, Turkey
SUMMARy
In this study, calcium carbonate (CaCO3) was coated by suitable chemicals using aqueous or dry coating methods
in the optimum conditions. Uncoated calcium carbonate having a mean particle size (d50) of 1.6 microns and a top
cut (d98) of 8 microns was provided commercially and it was dry and wet coated with saturated fatty acids whose
carbon numbers vary between 14 and 18. Coating amount was adjusted to 0.5-2%. Particle size and particle size
distribution of the calcium carbonates before and after coating were investigated. After characterization of the
coated calcium carbonates, they were incorporated into linear low density polyethylene (LLDPE) in changing
amounts using a twin screw extruder. The effects of coating chemicals, coating conditions and filler amount on
composite materials were studied by evaluating the thermal (DSC and TGA) and appearance (Scanning Electron
Microscope (SEM)) analyses.
Keywords: Calcium carbonate; Fatty acid; Stearic acid; Compounding; Particle size

Calcium carbonate being one of the most abundant minerals in nature,which is available in 4 different qualities(marble,limestone,chalkand travertine) in nature, has been produced according to two methods, i.e., ground
(GCC) and precipitated calcium carbonate (PCC) and used frequently in a wide range of applications including paper, paint, food, ceramic, construction, ink, adhesive, drug,cable, and plastic industries1-2. Calcium carbonate has been used as a filler in plastics since it is abundant in nature and a very cheap mineral. More than 80% of the fillers used in thermoplastics are based on calcium carbonate minerals.Calcium carbonate is traditionally used in plastics as bulking agent to substitute the expensive polymers4.
It is difficult to distribute calcium carbonate homogeneously in plastic materials since it has a hydrophilic and a lyophilic character. Therefore, calcium carbonate to be used in plastic industry is coated generally with stearic acid and its salts. Coating process may be chemical dissolving (dry coating) or spraying and it also carried out in emulsion, or in the form of aqueous solution application5. There are a lot of reasons for coating, e.g. to provide calcium carbonate a hydrophobic
structure and an improved brightness, to distribute it within a plastic material homogeneously without taking
moisture and agglomeration. One of the recent developing application fields of calcium carbonate in plastics industry
is also breathable films. Breathable films have many microvoids, which permit to pass water vapor but do not allow the water passage 

6-7. Breathable films are used in many fields such as roof covering, greenhouse coverings, bandages, surgical clothes, sportswear, children’s and adult diapers and sanitary towels 8-11.
The main purpose of present study is to investigate the effects of different coatingchemicals(fattyacids),coating conditions (dry, aqueous solution) and thefilleramountontheLLDPE/CaCO3 composite materials .

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calcium carbonate coating research

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