Studies of cure kinetics of polyisoimide by differential scanning calorimetry in the solid state

Abstract

Detailed kinetic studies of the thermal imidization of polyisoimide based upon 4,4′‐oxydianiline and 4,4′‐oxydiphthalic anhydride by differential scanning calorimetry are described. Both isothermal and dynamic methods have been used to obtain kinetic parameters and a phenomenological rate equation for estimating the degree of imidization as a function of time. The thermal imidization of polyisoimides in the solid state showed a maximum degree of imidization that can be achieved at a given isothermal temperature, probably due to the diffusion controlled characteristics of reactions near vitrification. That the reaction stopped near to the point of vitrification was considered when developing a phenomenological rate equation for thermal imidization of polyisoimide in the solid state. The thermal imidization is well described by modified first order kinetics with an activation energy of 170–181 kJ mol−1 and a pre‐exponential factor of 4.1 × 1013 s−1.© 2002 Society of Chemical Industry

Poly(amic acid)s and their poly(amide imide) counterparts containing azobenzene moieties: Characterization, imidization kinetics and photochromic properties

“…The PAA-2 polymer was synthesized at room temperature i.e., at the conditions typically applied for the synthesis of poly(amic acid) s [24,25]. However, for preparation of the PAA-1 and PAA-3 polymers the polycondensation reaction needed to be carried out at 120 C. 1 H NMR spectroscopy was used for determining the temperatures of the imidization reaction.…”

Studies of Thermal Imidization Kinetics of Polyisoimide Based upon 4,4′-[1,4-Phenylenebis-(1-methyl ethylidene)] Bisaniline and 4,4′-Oxydiphthalic Anhydride in Solid State

“…The relatively low activation energy values for the polyamic acid ester systems could be explained by considering the role of leaving groups in polyamic acid esters, removal of which relieves the steric hinderance and thereby functions as a driving force for the imidization reaction. In our earlier investigation of imidization of polyisoimide based upon 4,4 1 -oxydianiline/3,3 1 ,4,4 1oxydiphthalic anhydride in the solid state [24], the activation energy values were determined to be in the range of 170-181 kJ mol 31 , which are very similar to those for the BIS-P/ODPA polyisoimide system. This kind of result was also observed for the imidization of polyamic acid esters: in Snyder's study on the polyamic acid ester systems1 very little change in activation energy values was observed when dianhydride remained constant [25].…”

Novel acetylene‐terminated polyimide oligomers with excellent processability and high toughness of films

“…Landis and Naselow also have made lots of the early research. After that, the crosslinking and isomerization reactions of acetylene‐terminated polyisomide oligomers were studied by different methods, such as differential scanning calorimetry (DSC), Fourier transform infrared (FT‐IR), nitrogen‐15 solids Nuclear Magnetic Resonance ( 15 N‐NMR), and carbon‐13 magic‐angle spinning Nuclear Magnetic Resonance ( 13 C‐NMR) . Among all the acetylene‐terminated polyimides, thermid MC‐600 (M w =1099 g/mol), thermid IP‐600 (M w =1099 g/mol), and thermid FA‐700 (M w =1343 g/mol) which were produced by National Starch and Chemical Corp. have been as three commercially available products.…”