Non-isocyanate polyurethane foams based on six-membered cyclic carbonates

Effect of non-acoustic properties on the sound absorption of polyurethane foams

In this paper the influence of non-acoustic properties on the sound absorption coefficient of polyurethane foams as a porous medium is investigated. Biot’s equations with transfer matrix method, as the solution approach are employed to evaluate the sound absorption coefficient of selected polyurethane foams. The major issue is the dependency of non-acoustic properties on each other which makes ...

Electron-induced conversion of silylones to six-membered cyclic silylenes.

A silicon atom in the zero oxidation state stabilized by two carbene ligands is known as siladicarbene (silylone). There are two pairs of electrons on the silicon atom in silylone. This was recently confirmed by both experimental and theoretical charge density investigations. The silylone is stable up to 195 °C in an inert atmosphere. However, a substoichiometric amount (33 mol%) of potassium m...

The Modification of Polyurethane Foams Using New Boroorganic Polyols (II) Polyurethane Foams from Boron-Modified Hydroxypropyl Urea Derivatives

The work focuses on research related to determination of application possibility of new, ecofriendly boroorganic polyols in rigid polyurethane foams production. Polyols were obtained from hydroxypropyl urea derivatives esterified with boric acid and propylene carbonate. The influence of esterification type on properties of polyols and next on polyurethane foams properties was determined. Nitrog...

Tetrahydroxy 10-membered cyclic enediynes.

The preparation of cyclic 10-membered tetrahydroxy enediynes is reported. The synthesis starts from tartaric acid and allows the control of the relative stereochemistry. Acetal protection of the 2,3-hydroxy groups stabilizes the enediyne during synthesis. Removal of the cyclic protecting group with EtSH/TFA transforms the stable compounds into reactive enediynes, and the rate constants of their...

Synthesis of Polyurethane from One Hundred Percent Sustainable Natural Materials through Non-isocyanate Reactions