Poly urea-formaldehyde was synthesized simply and rapidly from urea and formaldehyde by condensation polymerization and studied for the sorption of trace acid blue from aqueous solution. The optimum pH value for sorption of the acid blue was 4. Experimental results showed that the sorption capacity of poly urea-formaldehyde for acid blue was determined. The synthetic polymer can be reused for 5...

Tissues in the body are hierarchically structured composite materials with tissue-specific properties. Urea self-assembles via hydrogen bonding interactions into crystalline supracolloidal assemblies that can be used to impart macroscopic pores to polymer-based tissue scaffolds. In this communication, we explain the solvent interactions governing the solubility of urea and thereby the scope of ...

Hindered urea bonds are introduced as self-healing units in a polymer electrolyte for Li-metal batteries. Differently from standard commercial separators, the poly(urea-urethane) system works hundreds of cycles after several damage/healing steps.

For more than a century, urea has been commonly used as an agent for denaturing proteins. However, the mechanism behind its denaturing power is still not well understood. Here we show by molecular dynamics simulations that a 7 M aqueous urea solution unfolds a chain of purely hydrophobic groups which otherwise adopts a compact structure in pure water. The unfolding process arises due to a weake...

paper only the treatments receiving commercial urea prills Using maize as the indicator crop for recently tilled soils over seven successive seasons, urea prills coated with 0,5% polymer gave the greatest grain yield increases over commercial urea in seasons of below average rainfall (3,3 tonsha versus 1,6 tonsha in 1989-90). The ratios of grain to stover were also higher. In wet years, no diff...

Results of the dielectric relaxation studies, performed for supramolecular polymer formed by N, N ′-di(2,2-dipentylheptyl)urea dissolved in carbon tetrachloride, are presented. The measurements were done for N, N ′-di(2,2-dipentylheptyl)urea concentration up to about 7% (in mole fraction) in the frequency region from 100 kHz to 100 MHz and at the temperatures from 5◦C to 50◦C. The analysis of t...

Urea is one of the final products of protein metabolism. In clinical analysis and dairy industry urea is a very significant parameter as excess in blood serum from its permissible range causes dysfunction of the kidney. Hence, its analysis is significant and is carried out frequently in various laboratories [1, 2]. Urea is an omnipresent compound present in blood and various organic fluids. It ...

Tissues in the body are hierarchically structured composite materials with tissue-specific chemical and topographical properties. Here we report the preparation of tissue scaffolds with macroscopic pores generated via the dissolution of a sacrificial supramolecular polymer-based crystal template (urea) from a biodegradable polymer-based scaffold (polycaprolactone, PCL). Furthermore, we report a...

Blending with a hydrogen-bonding supramolecular polymer is shown to be a successful novel strategy to induce microphase-separation in the melt of a Pluronic polyether block copolymer. The supramolecular polymer is a polybutadiene derivative with urea-urethane end caps. Microphase separation is analysed using small-angle X-ray scattering and its influence on the macroscopic rheological propertie...

Supramolecular polymers are linear chains of low molar mass monomers held together by reversible and directional non-covalent interactions, which can form gels or highly viscous solutions if the self-assembled chains are sufficiently long and rigid. The viscosity of these solutions can be controlled by adding monofunctional compounds, which interact with the chain extremities: chain stoppers. W...