2462 results about "Phthalic anhydride" patented technology

Polyimide copolymers were obtained containing 1,3-bis(3-aminophenoxy)benzene (APB) and other diamines and dianhydrides and terminating with the appropriate amount of reactive endcapper. The reactive endcappers studied include but should not be limited to 4-phenylethynyl phthalic anhydride (PEPA), 3-aminophenoxy-4'-phenylethynylbenzophenone (3-APEB), maleic anhydride (MA) and nadic anhydride (5-norbornene-2,3-dicarboxylic anhydride, NA). Homopolymers containing only other diamines and dianhydrides which are not processable under conditions described previously can be made processable by incorporating various amounts of APB, depending on the chemical structures of the diamines and dianhydrides used. By simply changing the ratio of APB to the other diamine in the polyimide backbone, a material with a unique combination of solubility, Tg, Tm, melt viscosity, toughness and elevated temperature mechanical properties can be prepared. The copolymers that result from using APB to enhance processability have a unique combination of properties that include low pressure processing (200 psi and below), long term melt stability (several hours at 300° C. for the phenylethynyl terminated polymers), high toughness, improved solvent resistance, improved adhesive properties, and improved composite mechanical properties. These copolyimides are eminently suitable as adhesives, composite matrices, moldings, films and coatings.

A multivariable method and process controller is for controlling a catalyzed chemical reaction to form phthalic anhydride (PA), produced by a production unit including a chemical reactor having a plurality of pipes connected in parallel having inner surfaces affixed with at least one solid catalyst. The reactor implements a process for forming PA by receiving flows of reagents including at least one oxidizable substituted aromatic and an oxygen including source gas at one or more inlets of the reactor. A dynamic multivariable model for the process represents the effects of moving a plurality of manipulated variables (MVs) including a flow of the oxygen including source gas and a flow or temperature of the oxidizable substituted aromatic on controlled variables (CVs) including a temperature at a plurality of positions along a length of the pipes. During the process, a first parameter related to performance of the catalyst in producing PA and a second parameter including a temperature at one or more of the plurality of positions in measured. Using the dynamic model, the temperature in the plurality of positions along the length of the reactor are automatically adjusting based on at least the first measured parameter, which permits the temperature profile to be adjusted to compensate for ageing of the catalyst to improve production efficiency.