Buzlanmayı engelleyici polimer kompozit filmler ve sulu polimler çözeltileri

Anti-icing solutions and coatings have been in great demand in applications which stimulated scientific studies to develop new material systems having anti-icing functionality and to understand their anti-icing mechanisms. Water soluble polymers are effective anti-icing agents for aqueous solutions. Nanoparticle/polymer composite coatings are good candidates for effective anti-icing functionality provided that they are hydrophobic and have surface roughness at different length scales. We investigated the freezing and melting behavior of aqueous solutions of poly (ethylene glycol) (PEG) and poly (2-ethyl-2-oxazoline) (PEOx) by differential scanning calorimetry. The effect of polymer concentration (1-80 g/L) and molecular weight (2,000 ? 400,000 g/mol) on the freezing/melting of aqueous solutions was reported. The melting of bound water was observed at ~ ? 11 °C in PEG solutions. Higher molecular weight PEG samples were more effective in decreasing the onset temperature of melting of ice at 0 °C and in forming more frozen bound-water that melted around ~ ? 8 °C. Bound water was also present in aqueous PEOx solutions, but did not freeze down to ? 60 °C. A glass transition was observed at ~ ? 26 °C in aqueous PEOx solutions which confirmed that bound water was not frozen. The strong amide dipoles of PEOx and the resulting strong hydrogen bonds between water molecules and PEOx are expected to be responsible for the observed phenomena. In the second part of the thesis, hydrophobic silica nanoparticle/styrene-butadiene-styrene (SBS) block copolymer composites were prepared and the anti-icing functionality of their coatings was tested as a function of nanoparticle concentration. Nanoparticles caused surface morphology and surface wettability of SBS coatings to change gradually up to ~ 43% by mass above which the morphology and wettability were rather constant. The water droplets showed the longest freezing times on composite coatings whose composition was close ~ 43%, corresponding to the transition in surface morphology and wettability. The coating containing 43 % by mass nanoparticle showed the longest freezing delay of 3718 s and 980 s at ? 4 °C and ? 8 °C surface temperatures, respectively. The composite material was added into bitumen to give anti-icing functionality to bitumen. Modified bitumen coatings containing 20-30% nanoparticles also showed delayed freezing of water droplets on them at surface temperatures of ? 8 °C and ? 10 °C. The laboratory results are promising for obtaining modified bitumen that has anti-icing functionality and better mechanical properties.