Progress in Organic Coatings 77 (2014) 609–615 Contents lists available at ScienceDirect Progress in Organic Coatings jou rn al hom ep age: www.elsevier.com/locate/porgcoat Comparative analysis of organosilicon polymers of varied chemical composition in respect of their application in silicone-coating manufacture Wacław Brachaczek ∗ Faculty of Materials and Environmental Sciences, University of Bielsko-Biala, St. Willowa 2, 43-300 Bielsko-Biala, Poland a r t i c l e i n f o Article history: Received 15 February 2013 Received in revised form 13 November 2013 Accepted 26 November 2013 Available online 31 December 2013 Keywords: Organosilicon polymer Silicone resin Silicone coating Multiple regression a b s t r a c t The present article describes the basic properties of organosilicon polymers applied in the manufacture of protective building coatings. The factors affecting the surface water absorption of silicone paint coatings were determined. It was ascertained that the types and contents of the applied hydrophobizing addi- tives, as well as the silicone and organic resins, had a strong influence on this parameter. A comparative analysis of the recipe configurations incorporating varying amounts of silicone and organic polymers was conducted. A strong similarity was observed between the effects of organosilicon polymers of varied chemical structures on the surface water absorption of the obtained coatings. For this purpose, statistical models based on multiple regression were proposed. The dependencies of the interaction between the analysed factors were presented in the form of mathematical dependencies. © 2013 Elsevier B.V. All rights reserved. 1. Introduction In preparation for the application of products used in the man- ufacture of protective building coatings, they can be divided – with respect to the applied binder – in two basic groups: polymeric (with the use of organic dispersions) and silicate (containing water glass as a binder). Further division is connected with the successive mod- ifications of the binding systems of the above-mentioned groups [1,2,11–13]. The usage of polysiloxanes in technological recipes is an important modification. Despite the fact that their addition does not have a significant effect on the binding properties, the products of such modifications have been selected as separate groups: sili- cone and silicate–silicone paints, respectively. This is associated with the fact that the addition of polysiloxanes has a significant effect on the change in the physical properties of the final protective coatings [3–7]. From a chemical point of view, polysiloxanes – also known as ‘silicones’ – constitute a class of organosilicon polymers of the gen- eral formula (R 3-n SiO n ) x , where n > 0, x > 2 and R = alkyl (usually methyl), aryl(usually phenyl) or H. The individual structures of such groups with varying R/O ratios, marked with the letters M, D, T and Q, represent the respective units R3 Si O 0.5, R 3 SiO 0.5 , R 2 Si(O 0.5 ) 2 , RSi(O 0.5 ) 3 , Si(O 0.5 ) 4 (see Fig. 1). ∗ Tel.: +48 500 030 700; fax: +48 33 496 06 10. E-mail address: wbrachaczek@ath.bielsko.pl For the manufacture of facade protective coatings of polysilox- anes of a linear structure, so-called silicone oils with the inclusion of M and D units are generally used, as well as silicone resins incor- porating elements of the T-type attached to their main chain, and in addition to the previously mentioned M and D units [3,4,6,8,12]. The key feature favouring the wide application of polysiloxanes in this sector of manufacture is their high permeability to water vapour, the low surface tension of silicones themselves favouring good surface wetting, high thermal and UV radiation resistance and, above all, the high hydrophobicity of the surface coated with silicone film [1,3,7,13]. The low surface tension of the silicones (around 20.4 mN/m), associated with the 50% ionic character of the Si O bonding, facil- itates both the easy wetting of various surfaces by silicones and the easy formation of silicone-containing coatings [3]. The pres- ence of hydrocarbons – mainly methyl – oriented in the direction opposite to the wetted surface, makes the adhesive surface ten- sion of the polyorganosiloxanes 1.5–2 times higher than their own surface tension. Consequently, they display a unique hydropho- bic and anti-adhesive nature, especially when in cross-linked form [3,5,9,11]. The hydrophobizing properties of silicone compounds depend on the amount of hydrophobic substituents attached to the siloxane backbone as well as the structure of these substituents, in particular their type and spatial-orientation ability on a hydrophobic surface. Along with methyl and phenyl substituents, other aliphatic groups with longer chains (octyl) are also applied as well as aliphatic 0300-9440/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.porgcoat.2013.11.026