Copolyimide with a combination of flexibilizing groups

Copolyimides are prepared by reacting one or more aromatic dianhydrides with a meta-substituted phenylene diamine and an aromatic bridged diamine. The incorporation of meta-substituted phenylene diamine derived units and bridged aromatice diamine derived units into the linear aromatic polymer backbone results in a copolyimide of improved flexibility, processability, and melt-flow characteristics. The copolyimides are especially useful as thermoplastic hot-melt adhesives

A Process for Preparing 1,3-Diamino-5-Pentafluorosulfanylbenzene and Polymers Therefrom

Diamines have shown their utility in the formation of many polymers. Examples of these polymers include polyimides, polyamides, and epoxies. The properties of these polymers are often dependent on the diamine which is used to make the polymer. By the present invention, a process was developed to make a diamine containing pentafluorosulfanylbenzene moiety. This process involves two steps: the preparation of a dinitro precursor and the reduction of the dinitro compound to form the diamine. This diamine was then reacted with various dianhydrides, diacidchlorides, and epoxy resins to yield the corresponding polyimide, polyamide, and epoxy polymers. These polymers were then used to make films, a wire coating enamel, and a semi-permeable membrane. The novelty of this invention resides in the process to make the diamine. Traditionally, dinitro compounds are reduced with hydrazine or a catalyst such as palladium on charcoal. The catalyst which is used in this invention is platinum oxide. When this catalyst is used, it makes it possible to form a polymer-grade diamine

Elastomeric silazane polymers and process for preparing the same Patent

Preparation of elastomeric diamine silazane polymer

Polyimide molding powder, coating, adhesive, and matrix resin

The invention is a polyimide prepared from 3,4'-oxydianiline (3,4'-ODA) and 4,4'-oxydiphthalic anhydride (ODPA), in 2-methoxyethyl ether (diglyme). The polymer was prepared in ultra high molecular weight and in a controlled molecular weight form which has a 2.5 percent offset in stoichiometry (excess diamine) with a 5.0 percent level of phthalic anhydride as an endcap. This controlled molecular weight form allows for greatly improved processing of the polymer for moldings, adhesive bonding, and composite fabrication. The higher molecular weight version affords tougher films and coatings. The overall polymer structure groups in the dianhydride, the diamine, and a metal linkage in the diamine affords adequate flow properties for making this polymer useful as a molding powder, adhesive, and matrix resin

Development of a polyimide for use as a temperature and solvent resistant sealant

Polyimide developed by the interaction of benzophenone tetracarboxylic dianhydride, polyoxypropylene diamine, and oxydianiline is used for fuel tanks that are exposed to extreme temperatures

Asymmetric organocatalysis of the addition of acetone to 2-nitrostyrene using N-diphenylphosphinyl-1,2-diphenylethane-1,2-diamine (PODPEN)

The highly enantioselective addition of acetone to 2-nitrostyrene, using N–diphenylphosphinyl-trans-1,2-diphenylethane-1,2-diamine (PODPEN) as catalyst, is described

Tribological evaluation of composite materials made from a partially fluorinated polyimide

Preliminary tribological studies on a new polyimide formulated from the diamine 2,2-bis 4-(4-aminophenoxy) phenyl hexafluoropane (4-BDAF) indicates polyimides made from this diamine have excellent potential for high temperature applications. Two different polyimides were formulated from the diamine, and five different composites were formulated using one of the polyimides. Composites were made using 10 weight percent (w/o) graphite fluoride powder, 20 w/o PTFE powder, 30 w/o silver powder, or 50 w/o carbon fibers, both graphitic and nongraphitic types. The powder additions did not improve the tribological properties as much as the carbon fibers, and the graphitic fibers produced better results than did the nongraphitic fibers. Results also indicated that improved high temperature stability and tribological properties may be obtained with a polyimide made from the dianhydride pyromellitic acid (PMDA) rather than the dianhydride benzophenonetetracarboxylic acid (BTDA)

New Condensation polyimides containing 1,1,1-triaryl-2,2,2-trifluoroethane structures

The invention relates to a condensation polyimide containing a 1,1,1-triaryl 2,2,2-trifluoroethane structure and other related condensation polyimides. The process for their preparation, which comprises polymerization of a cyclic dianhydride with a diamine is also covered

HAIR DYE- AN EMERGING SUICIDAL AGENT: OUR EXPERIENCE

Hair dye poisoning has been emerging as one of the important causes of intentional deliberate self harm. To study the epidemiology of patients who consumed Super Vasmol (a commonly used commercial hair dye), profile of patients referred to the ENT department, to find the effectiveness of supportive therapy and to compare between the tracheostomy and the non tracheostomy group, a retrospective study was conducted inpatients who consumed Super Vasmol admitted over a year (April 2009 – March 2010) in a teaching hospital in South India. Out of the 108 patients 38 (35.2%) were males and 70 (64.8%) were females. 42 (38.9%) were in 21-25 age group. Patients who developed cervico-facial oedema, throat pain, burning sensation in the throat, change of voice, no voice and dyspnoea with stridor were referred to the ENT Department. 74 (68.5%) patientsneeded an ENT opinion. Cervico-facial oedema was the main clinical manifestation in 74 patients. 33 of themunderwent tracheostomy. The mortality in 108 patients was 22.2% and after tracheostomy 21.2%. Purpose of thestudy is to create public awareness about the lethal effects of the hair dye, because it is a major health problem and to educate the public and the medical professional about the need for aggressive and early treatment.

Direct synthesis of polymeric schiff bases from two amines and two aldehydes Patent

Direct synthesis of polymeric schiff bases from two amines and two aldehyde