Synthesis and characterization of new water‐soluble precursors of polyimides

Abstract

We have successfully synthesized and characterized new water‐soluble precursors of polyimides based on dianhydrides with diaminobenzene sodium sulfonate (DABSS) and diaminostilbene disodium sulfonate (DASBDSS). The precursors are soluble in water and methanol as well as in several aprotic solvents. The optimum inherent viscosities of the poly(amic acids), obtained by varying reaction temperatures, were measured using a conventional Ubbelohde viscometer. The average molar mass of the polymers expressed as the “poly(ethylene oxide)‐PEO/poly(ethylene glycol)‐PEG equivalent” molecular masses obtained by gel permeation chromatography (GPC) showed significant broad molecular mass distributions with their polydispersities ranging from 2.9 to 4.6. FT‐IR spectra revealed complete imidization of the polyimides. Their thermal properties were studied by techniques such as differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Polyimides derived from the dianhydrides and DASBDSS showed better thermal stability up to 40°C in nitrogen than in oxygen atmosphere. However, polyimides based on the dianhydrides and DABSS were slightly more stable in oxygen than in nitrogen atmosphere. In oxygen, all the synthesized polyimides exhibited weight losses of about 50% in the range of 450–510°C. The overall weight losses of these polyimides under nitrogen were less than 50% at 700°C. New network polymellitimides based on mellitic trianhydride (MTA) and DABSS, and co‐polymellitimides based on MTA, DABSS, and ODA (oxydianiline) were also synthesized and characterized successfully. Their thermal stabilities were compared with the linear polyimides using TGA and DSC.

Ladder-Like Aromatic Imide-Functionalized Poly(silsesquioxane): Preparation and Characterization via the Sol-Gel Route

“…c is that the amide I band (1625 cm −1 ) and the amide II (1579 cm −1 ) band have disappeared, indicating that PAA has been converted into a polyimide. The band at 1394 cm −1 is assigned to the C–N stretching mode of the imide group (imide II) . As mentioned earlier, the bands at 1200–1000 cm −1 are ascribed to the vibration modes of the siloxane (Si–O–Si) groups.…”

“…As mentioned earlier, the bands at 1200–1000 cm −1 are ascribed to the vibration modes of the siloxane (Si–O–Si) groups. The absorption band at 729 cm −1 can be associated with the bending carbonyl vibration (imide IV) . Figure d shows the IR spectrum of the xerogel, which is obtained when PMDA reacts with APTES in a molar ratio of 1:2 at 220°C.…”

“…The band at 1394 cm −1 is assigned to the C-N stretching mode of the imide group (imide II). 22,23 As mentioned earlier, the bands at 1200-1000 cm −1 are ascribed to the vibration modes of the siloxane (Si-O-Si) groups. The absorption band at 729 cm −1 can be associated with the bending carbonyl vibration (imide IV).…”

Characterization, properties, and processing of LaRC? PETI-5 as a high-temperature sizing material. I. FTIR studies on imidization and phenylethynyl end-group reaction behavior

“…The FTIR method has been also successfully used in many research areas to study cure, 16 thermal aging, 17 crosslinking reaction, 18 semi-interpenetrating network, 19 -20 as well as structure identification [21][22] of polyimides. The overall research objective of this work is ultimately to enhance fibermatrix interfacial properties in high-performance polymer matrix composites reinforced with carbon fibers or glass fibers by incorporating LaRC™ PETI-5 as a high-temperature sizing material for better adhesion and toughness.…”

Phenylethynyl-terminated polyimide, exfoliated graphite nanoplatelets, and the composites: an overview

“…In the 1990s a variety of phenylethynyl-in many research areas to study the curing [25], thermal aging [26], crosslinking reaction [5], semi-interpenetrating networks [27,28], as well as structure identification [29,30] of polyimides.…”