Chemical and Thermo-Mechanical Properties of Waterborne Polyurethane Dispersion Derived from Jatropha Oil

Nowadays, there is a significant trend away from solvent-based polyurethane systems towards waterborne polyurethane dispersions due to government regulations requiring manufacturers to lower total volatile organic compounds, as well as consumer preference for more environmentally friendly products. In this work, a renewable vegetable oil-based polyol derived from jatropha oil was polymerized with isophorone diisocyanate and dimethylol propionic acid to produce anionic waterborne polyurethane dispersion. Free standing films with up to 62 wt.% bio-based content were successfully produced after evaporation of water from the jatropha oil-based waterborne polyurethane (JPU) dispersion, which indicated good film formation. The chemical and thermo-mechanical properties of the JPU films were characterized. By increasing the OH numbers of polyol from 161 mgKOH/g to 217 mgKOH/g, the crosslinking density of the JPU was significantly increased, which lead to a better storage modulus and improved hydrophobicity. Overall, JPU produced from polyol having OH number of 217 mgKOH/g appears to be a promising product for application as a binder for wood and decorative coatings.

Polyurethane filled with modified basalt fiber

The use of basalt fiber as a reinforcing filler is mainly used instead of glass fibers due to its unique properties. Basalt fiber in comparison with glass has a 10-22% greater modulus, higher absolute strength after exposure to 400 °C, superior to glass in alkali and especially acid resistance, approximately identical in water resistance, i.e. close in properties to high-modulus glass fibers. However, it is most often used as a filler for concrete and other building structures. There is much less information about its use as a polymer reinforcing filler. The polymer matrix for creating polymer composite materials is most often epoxy resins, less often polyester. At the same time, there is practically no data on polyurethanes that have a unique combination of high strength indicators with elasticity and hardness, resistance to solvents and aggressive media, abrasion resistance, etc. The use of basalt fiber as a filler that increases the strength characteristics of polyurethanes and gives them specific properties can significantly expand the scope of their application. In this regard, this study attempts to use crushed basalt fiber as a reinforcing filler for polyurethanes. In order to increase the adhesion of the polymer matrix – filler system, an adhesive based on water-based polyurethane dispersion is used. Samples were obtained based on a polyurethane binder filled with basalt fiber in amounts up to 10.0 % by weight, treated with water-polyurethane dispersion with a concentration of 10 to 20 % by weight. The best complex of strength properties is provided by polyurethanes filled with basalt fiber in the amount of 1.0% by weight, treated with 15 % by weight water-based polyurethane dispersion. At the same time, the tensile strength increased by 15% compared to the same filling without processing and by 50% compared to the unfilled analog and amounted to 33.7 MPa. These changes are explained by a more uniform distribution of crushed basalt fiber in the polymer matrix and an increase in the adhesion interaction of fiber-adhesive-polymer matrix due to the biphilicity of the adhesive, as well as the same (polyurethane) nature of the adhesive and the matrix. The developed polymer composite materials have high hydrolytic resistance, as well as resistance to acetone and hexane. At the same time, the greatest degree of swelling did not exceed 0.9 % of the mass.

The Puncture and Water Resistance of Polyurethane- Impregnated Fabrics after UV Weathering

Polyurethane is a polymer adaptable to different scientific and industrial requirements; nevertheless it is also extremely susceptible to UV radiation, which compromises the physical and mechanical functionality. In this framework, our study investigated the effect of waterborne polyurethane dispersion (WPUD) applied to a polyester (PET)-based fabric, through the impregnation method, on the puncturing and water resistance of the pristine material, before and after UV weathering. Results confirmed an increment of both features in the prepared fabrics, attributed to the PUR textile treatment; but a partially loss of the gained properties in the samples due to the UV weathering. In order to improve the efficiency of the impregnating dispersions, in protecting the durability of the treated materials, the addition of different UV light stabilizers, or/and of crosslinking agent into WPUD was also tested. From the experimental data, it can be concluded that formulations based on WPUD, containing both the crosslinker and UV organic absorber, have displayed an increment of their perforation and water resistance for the treated samples with respect to the starting textile, and contemporary have preserved the features against the UV light. Finally, microscopic and spectroscopic analyses have been performed as further characterization techniques of the samples surface.