Polyimides poly imide

A large number of high-performance polymer systems are formed by the condensation reactions of diamines, or diols with aromatic diacids, or their derivatives. These include commercially successful products such as aramids, polyimides, poly(imide-amides), and polyesters. While some of the monomers used in the production of these polymers are readily available and made in large quantities, it is becoming more common to use smaller quantities of speciality monomers to tailor the properties of the resultant polymers to suit a specific application. To address this need, chemistries using unconventional monomers are being explored to offer alternative routes to a variety of polymeric systems. 

FIG. 3 Evolution with time, f, of contact angle, of NMP, with NMP containing 17.5 wt% of poly-imide and NMP containing 28 wt% of polyimide. 

This observation is further dramatized by some rather limited isothermal measurements on selected films (TABLE III). This data is typical of the metal ion filled BTDA + p,p -DABP poly-imides which we have examined. No changes in chemical functionality in the polyimide-metal film were apparent as judged by infrared spectral comparisons of polyimide alone and polyimide plus metal regardless of the metal employed. 

After cleaning by abrasion and with solvents, the polyimides can be stuck with a poly-imide, epoxy or acrylic resin adhesive whose thermal resistance is compatible with the operating conditions. Preliminary tests are essential. 

Thus, N-pyrimidine phthalimide reacted with hexylamine at room temperature to form an amide-amide. The initial amide-amide formation proceeded more rapidly in chloroform as compared to dimethylsulfoxide (DM SO). However, the ring closure reaction to the imide was favored by the more polar, aprotic DMSO solvent, yielding the imide in nearly quantitative yield after 3 hours at 75 °C. The authors were able to utilize this synthetic approach to prepare well-defined segmented poly(imide-siloxane) block copolymers. It appears that transimidi-zation reactions are a viable approach to preparing polyimides, given that the final polyimide has a Tg sufficiently low to allow extended excursions above the Tg to facilitate reaction without thermal decomposition. Additionally, soluble polyimides can be readily prepared by this approach. Ultimately, high Tg, insoluble polyimides are still only accessable via traditional soluble precursor routes. 

Addition poly(imide) oligomers are used as matrix resins for high performance composites based on glass-, carbon- and aramide fibers. The world wide market for advanced composites and adhesives was about 70 million in 1990. This amounted to approximately 30-40 million in resin sales. Currently, epoxy resins constitute over 90% of the matrix resin materials in advanced composites. The remaining 10% are unsaturated polyester and vinylester for the low temperature applications and cyanate esters and addition poly(imides) for high temperatures. More recently thermoplastics have become important and materials such as polyimides and poly(arylene ether) are becoming more competitive with addition polyimides. 

Throughout this chapter the chemical concepts employed to synthesize and cure addition poly(imides) have been discussed and their use as matrix resins for fiber composites has frequently been mentioned. The most important property of the imide backbone structure is the inherent thermal stability. The target of achieving the temperature performance of linear poly(imide) has not been reached, because of the aliphatic nature of the reactive endgroups, and because of the low molecular weight of the imide backbone required for processing. Future developments of addition polyimides will, as in the past, focus on the requirement of high thermal and thermal oxidative stability of the crosslinked... 

POLYIMIDES. These are heat-resistant polymers which have an imide group (—CONHCO-) in the polymer chain, Polyimides, poly(amide-imides), and poly(esterimides) are commercially available,... 

MC MDI MEKP MF MMA MPEG MPF NBR NDI NR OPET OPP OSA PA PAEK PAI PAN PB PBAN PBI PBN PBS PBT PC PCD PCT PCTFE PE PEC PEG PEI PEK PEN PES PET PF PFA PI PIBI PMDI PMMA PMP PO PP PPA PPC PPO PPS PPSU Methyl cellulose Methylene diphenylene diisocyanate Methyl ethyl ketone peroxide Melamine formaldehyde Methyl methacrylate Polyethylene glycol monomethyl ether Melamine-phenol-formaldehyde Nitrile butyl rubber Naphthalene diisocyanate Natural rubber Oriented polyethylene terephthalate Oriented polypropylene Olefin-modified styrene-acrylonitrile Polyamide Poly(aryl ether-ketone) Poly(amide-imide) Polyacrylonitrile Polybutylene Poly(butadiene-acrylonitrile) Polybenzimidazole Polybutylene naphthalate Poly(butadiene-styrene) Poly(butylene terephthalate) Polycarbonate Polycarbodiimide Poly(cyclohexylene-dimethylene terephthalate) Polychlorotrifluoroethylene Polyethylene Chlorinated polyethylene Poly(ethylene glycol) Poly(ether-imide) Poly(ether-ketone) Polyethylene naphthalate Polyether sulfone Polyethylene terephthalate Phenol-formaldehyde copolymer Perfluoroalkoxy resin Polyimide Poly(isobutylene), Butyl rubber Polymeric methylene diphenylene diisocyanate Poly(methyl methacrylate) Poly(methylpentene) Polyolefins Polypropylene Polyphthalamide Chlorinated polypropylene Poly(phenylene oxide) Poly(phenylene sulfide) Poly(phenylene sulfone)... 

The second approach has the advantage that it provides flexibility in the choice of means to perform the printing. Figure 10.14 shows a stamp with this construction, designed for plastic electronics applications [42]. It consists of a thin layer of PDMS on top of a sheet of polyimide. The relatively high in-plane modulus of the poly-imide prevents distortions that can frustrate registration. Its small thickness enables the stamp to be bent in a manner that facilitates printing. 

US 5,028,681 (American) 1991 Novel poly(imide siloxane) block copolymers and process for their preparation General Electric EN Peters Injection moldable block copolymers with high IV and excellent chemical/physical properties. Blends useful for impact modification Novel siloxane-imide block copolymers and a process for their preparation are covered. The method involves reacting a hydroxy-terminated polyimide oligomer with a siloxane oligomer with dimethylamino, acetyl or chlorine end-groups... 

Bowens AD, Sensenich CL, Venkatesan V, Robertson MA, McCartney SR, Lesko JJ, Riffle JS (1997) Waterborne polyimides and poly(imide-siloxane)s. Polym Prepr, Am Chem Soc. Div Polym Chem, 38(2) 632... 

Saraf RF, Feger C, Cohen YC Structure of poly(imide siloxane) Adv. Polym Sci and Tech. Proc. of the 4th Inti Conf on Polyimides. Feger C, Khojasteh MM, MS Htoo MS (eds) pp 433-440, Ellenville New York... 

Yoon TH, Arnold-McKenna CA, McGrath JE (1992) Adhesion behavior of thermoplastic polyimides and poly(imide siloxane) segmented copolymers influence of test temperatures J Adhes 39(100) 15... 

Moyer ES, Mohanty DK, Shaw J and McGrath JE (1989) Synthesis and characterization of soluble photoimageable polyimide and poly(imide siloxane) homo- and copolymers. 3rd International SAMPE Electronics Conference, p 894... 

The use of static SIMS for the characterization of surfaces of polypropylene (PP), PTFE and a PMDA-ODA type poly-imide is described. Interfaces between evaporated copper or chromium films onto PTFE and polyimide were also analyzed. Some of the polymer substrates were modified by ion beams, corona discharge in air or plasma treatments in air, At and H2. It is demonstrated that SIMS is highly complementary to XPS for the analysis of such modified surfaces, in that effects such as crosslinking, unsaturation and formation of low-molecular weight material at surfaces can be detected. 

Thompson, D.S., Thompson, D.W., and Southward, R.E. (2002) Oxo-metal-polyimide nanocomposites. 2 enhancement of thermal mechanical and chemical properties in soluble hexafluoroisopropyUdene-based poly-imides via the in situ formation of oxo-lanthanide(III)-polyimide nanocomposites. Chemistry of Materials, 14,... 

The traditional approach used in poly(imide-siloxane) synthesis is the reaction of aminopropyl-terminated dimethylsiloxane oligomers with aromatic dianhydrides and additional diamines (9-13). Typically, subambient temperatures and dipolar aprotic solvents are used. The resulting high-molecular-weight polyamic acid solution can be heated to effect imidization and solvent evaporation. This procedure is analogous to the synthetic method used to prepare conventional polyimides for films and coatings. 

Special considerations trace metals such as Co, Cu, Ni radically reduce thermal stability some carbon fibers cause degradation due to the surface impurities some types of glass reduce stability of poly imide polyimide is used as modifier of PEEK/carbon fiber composite " ... 

---