Morphological properties of fillers for polymeric materials; the influence on rheological properties of compositions with unsaturated polyester resin

Ewa KUŻDŻAŁ*, Barbara CICHY, Szymon DULIK – New Chemical Syntheses Institute, Division of Inorganic Chemistry „IChN” in Gliwice, Gliwice, Poland
Please cite as: CHEMIK 2016, 70, 185–192

Organic synthetic polymers are the base of many modern materials which are replacing traditional ones. Modifications of traditional polymers have increasing market share. One of the most frequently used methods of polymer modification is filling. Fillers are introduced to the material. It improves mechanical and heat properties and reduce the price of the product. It should not be expected that filling will improve all of the desired properties. Usually improving one of the features leads to worsening other properties. One of the most frequently observed drawbacks of using fillers is worsening of rheological properties.

Effect of fillers on mechanical, dielectric and thermal properties of polymer-filler composite is significant. Usefulness of fillers is not only a result of their composition. Mechanical properties such as specific density, size, shape, specific surface area and porosity of the grain also have the impact [1 – 3]. Morphological structure of fillers mainly influences rheological and mechanical properties of obtained material [4, 5]. Flame retardants have great importance among the fillers.

Some of the fillers have a negative effect on polymers even if they are used in small amounts. Other ones do not have any impact. It is observed that even the fillers of a similar composition but different grain morphology have various impact. It can be assumed that grain size, its shape and specific surface area are the determining factors influencing the polymer properties. The authors of the publications [6, 7] described the influence of grain diameter on viscosity of the composite. The authors of [8] observed the dilatation effect – an increase of viscosity with an increase of shear strength, by introducing fillers of different diameters.

An influence of shape factor on polymer composite viscosity is described in publications [6, 9–10]. The authors claim that viscosity of a filled polymer is inversely proportional to shape factor of a filler grain. This dependence is confirmed by the studies [11–13].

Among morphological properties of fillers, grain specific surface area has a significant impact on composite viscosity. Viscosity of a filled material increases with specific surface area of a filler grain [14, 15].

Unsaturated polyester resins (UP) are widely applied to produce many construction materials. UPs are used to produce glass-polyester tubes (GRP) manufactured in centrifugal casting process [16].

The problem of rheological properties of composites based on UPs is the subject of publications [17, 18]. The authors examined the influence of many UP modifiers on rheological properties of composites. These modifiers were among others bentonites and nanoclays.

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