摘要:
The present invention provides an electromechanical transducer comprising a dielectric elastomer with contact by a first electrode and a second electrode, said dielectric elastomer comprising a polyurethane polymer comprising the reaction product of A) a polyisocyanate and/or B) a polyisocyanate prepolymer with C) a compound having at least two isocyanate-reactive groups wherein the polyisocyanate prepolymer B) and/or the compound C) having at least two isocyanate-reactive groups comprise polytetramethylene glycol ether units of the formula (I): —[O—CH2-CH2-CH2-CH2-]n (I) where n≧25; and with a minimum value nmin for the value n and a maximum value nmax for the value n in the formula (I) selected such that the difference between nmax and nmin is ≧0 to ≦4. The present invention further provides a process for producing such an electromechanical transducer, and to an electric and/or electronic device including the inventive electromechanical transducer.
摘要:
The invention relates to carbon nanotubes comprising hydroxy groups, wherein the surface thereof comprises hydroxy alkyl ester groups covalently bound thereon, chosen from the group according to the general formula (1) and/or the general formula (2), wherein (CNT) stands for the surface of the carbon nanotube and R1 and R2 are independently from each other hydrocarbon, an alkyl radical or an aryl radical. The invention further relates to a method for the production thereof by means of reaction of carbon acid groups of the carbon nanotubes with an epoxy, furthermore a polyurethane polymer, wherein said carbon nanotubes are covalently bound, a method for producing a polymer of said kind and use of the carbon nanotubes for producing polymers.
摘要:
The invention provides a process for producing rigid polyurethane-polyisocyanurate foams using polyols having a high proportion of secondary hydroxyl end groups. The invention further relates to the rigid polyurethane-polyisocyanurate foams thus obtainable and to the use thereof in the production of composite elements from rigid polyurethane-polyisocyanurate foams and suitable outer layers. The invention further provides the composite elements thus obtainable.
摘要:
The invention relates to stable emulsions for the production of foams based on isocyanate, at least comprising three polyols A1a, A1b and A1c as well as at least one physical blowing agent T, wherein A1a is a polyether polyol obtained by addition of epoxides to starter compounds selected from carbohydrates and di- or higher-functional alcohols, A1b is a polyether polyol started on an aromatic amine, and A1c is a polyester polyol obtained by esterification of a polycarboxylic acid component and a polyalcohol component, wherein the total amount of aromatic dicarboxylic acid derivatives used in the esterification, calculated on the basis of the free aromatic dicarboxylic acids and based on the total mass of polyalcohol component and polycarboxylic acid component, is less than or equal to 48.5% by mass.
摘要:
The invention relates to a process for the preparation of carbon nanotubes having hydroxyalkyl ester groups by reacting carbon nanotubes which have carboxylic acid groups with one or more epoxides, and to dispersions and materials which contain the carbon nanotubes functionalized thus.
摘要:
The present invention relates to NCO prepolymers having a low content of free monomeric diisocyanate, to a process for the production of these NCO prepolymers, to polyurethanes prepared from these NCO prepolymers and to processes for the production of these polyurethanes.
摘要:
The present invention relates to NCO prepolymers having a low content of free monomeric diisocyanate, to a process for the production of these NCO) prepolymers, to polyurethanes prepared from these NCO prepolymers and to processes for the production of these polyurethanes.
摘要:
The present invention relates to high-quality polyurethane and polyurethane urea elastomers which exhibit unique combinations of processing characteristics, oxidation resistance, mechanical and mechanical/dynamic properties in particularly demanding applications. These polyurethane elastomers and polyurethane urea elastomers are based on novel polycarbonate polyols.
摘要:
The present invention relates to a process for the preparation of carbodiimide- and/or uretonimine-modified polyisocyanates by means of microwave radiation and to the use of such polyisocyanates for the synthesis of foamed and non-foamed polyurethane materials.
摘要:
A process for the preparation of polyricinoleic acid esters comprising the step of reaction of ricinoleic acid with an alcohol component which comprises mono- and/or polyfunctional alcohols having a molecular weight of ≧32 g/mol to ≦40 g/mol, wherein the reaction is carried out at least partly in the presence of a catalyst. The amount of catalyst, based on the total weight of the ricinoleic acid and the alcohol component, is in a range of from ≧10 ppm to ≦100 ppm. The reaction is ended when the acid number of the reaction product obtained is ≧5 mg of KOH/g to ≦100 mg of KOH/g. The invention furthermore relates to a polyurethane polymer, in particular a flexible polyurethane foam, which is obtainable using these polyricinoleic acid esters.