Abstract: The invention relates to the use of a powder made of a polymer, which of two or more components with functionalities suitable for Diels-Alder reactions, or of a powder mixture (dry blend) made of powders respectively of at least one of the reactive components, where these together enter into the Diels-Alder reaction with one another and are capable of a retro-Diels-Alder reaction, in a rapid-prototyping process. The invention further relates to moldings produced with use of said polymer powder through a layer-by-layer shaping process in which regions of a powder layer are melted selectively. The molding here can be removed from the powder bed after cooling and hardening of the regions previously melted layer-by-layer.

Abstract: A description is given of a photoreactive polymer preparable by radical polymerization using at least one photoreactive monomer, where the photoreactive monomer has at least one radically polymerizable C—C double bond, at least one hydrophilic group selected from an ethylene glycol group and polyethylene glycol groups having at least 2 ethylene glycol units, and at least one photoreactive group, the photoreactive group being a photoenolizable carbonyl group.

Abstract: Photoreactive monomer which has (i) at least one free-radically polymerizable C—C double bond, (ii) at least one hydrophilic group selected from an ethylene glycol group and a polyethylene glycol group having at least 2 ethylene glycol units and (iii) at least one photoreactive group, the photoreactive group being a photoenolizable carbonyl group, and also a method for preparing the photoreactive monomers.

Abstract: The present invention relates to innovative materials which can be crosslinked by means of two different crosslinking mechanisms, the first crosslinking mechanism being an irreversible crosslinking. The second crosslinking mechanism is a thermoreversible mechanism. As a result of this thermoreversible change in the arc length, properties of the crosslinked material can be decisively changed and controlled, including flexibility, elasticity and other mechanical properties, but also chemical properties, the gas permeability and vapour permeability and storage capacity of the network. In this way it would be possible, for example, to store energy sources such as fuels.

Abstract: The present invention relates to innovative materials which are reversibly crosslinkable by means of a thermoreversible mechanism and/or whose viscosity is reversibly adjustable. Through the use of bishydrazones or conjugated bis-Schiff bases as diene components in aza-Diels-Alder reactions, functional materials are generated that feature controllable viscosity and/or reversible crosslinking.

Abstract: The present invention relates to an innovative method for the reversible crosslinking of, for example, adhesives or coating materials. The reversible crosslinking method allows very rapid crosslinking even at room temperature and undoing of the crosslinks at higher temperatures, thereby regaining the capacity for thermoplastic processing and allowing the originally bonded substrates to be separated from one another again with ease. A particular aspect in this context is that a plurality of cycles of crosslinking and undoing of the crosslinks are possible with the present system.

Abstract: The present invention relates to an innovative method for controlling the viscosity of, for example, adhesives or coating formulations. The method for controlling viscosity allows very rapid thermoplastic curing of a formulation even at room temperature and a significant reduction in the viscosity at higher temperatures, thereby regaining the capacity for simple processing and allowing, for example, the originally bonded substrates to be separated from one another again with ease. A particular aspect in this context is that a plurality of cycles of thermoplastic curing and a significant reduction in the viscosity are possible with the present system.

Abstract: A new process is provided for preparing nitrile rubbers by free-radical polymerization in an organic solvent and in the presence of specific modifier substances. This polymerization may be followed by hydrogenation to give likewise new hydrogenated nitrile rubbers, the hydrogenation advantageously taking place likewise in organic solvent. The optionally hydrogenated nitrile rubbers obtained are notable for having fragments of the employed modifier substances in the main polymer chain and/or as end groups. They can he prepared with a wide diversity of molecular weights and polydispersity indices, especially with very low polydispersity indices.