Abstract
The goal of this work was to investigate the properties of environmentally friendly, castor oil based polyurethane hybrid materials with titanium(IV) oxide nanoparticles, as a filler, and different types of diisocyanate (toluene diisocyanate and isophorone diisocyanate). In the sample synthesis, different ratios of the reactive groups (NCO/OH), r, were used (1, 1.15 and 0.92).
In the composite preparation, only toluene diisocyanate was used, and the filler particles were premixed in a glass vessel with the castor oil polyol before the reaction with diisocyanate. For all the composite samples, the r value was 1.
Polyurethane formation was confirmed by ATR-FT-IR by detecting the urethane band at 1515 cm(-1). It was determined that the hydroxyl groups had reacted because the broad band corresponding to the OH groups (3400 cm(-1)) was not detected or detected at a reduced intensity depending on the r value.
As was expected, the presence of the unreacted NCO groups was detected only for samples with r > 1 (band at 2300 cm(-1), which corresponds to the existence of these groups). The dynamic mechanical measurements were performed at a temperature range from -50 degrees C to 100 degrees C at different frequencies.
For investigation of reinforcement effect of filler on polymer matrix, tensile testing was applied. The glass transition temperature, T-g, was determined by DSC measurement.
It was estimated that the T-g of the samples decreased as the nanofiller content increased due to the changes in the segmental mobility influenced by the interaction between the nanoparticles and polymer chains.