Addition polyimides. I. Kinetics of cure reaction and thermal decomposition of bismaleimides

Abstract

SynopsisThe thermal polymerization of four structurally different bismaleimide resins, prepared by reacting maleic anhydride with four aromatic diamines, viz., 4,4'-diaminodiphenyl methane, 4,4'-diamino diphenyl ether, 4,4'-diamino diphenyl sulfone, and 3,3'-diamino diphenyl sulfone, was followed by differential scanning calorimetry (DSC). The enthalpy change and the kinetic constants for the polymerization reactions were evaluated from the DSC curves. Thermal stability of the cured polymers was studied by therrnogravimetry (TG). The kinetic parameters, viz., activation energy E and preexponential factor A, for the thermal decomposition of the cured bismaleimides were calculated from the TG curves using three nonmechanistic integral equations.The kinetic constants ( E and A) follow a trend similar to the thermal stability of the polymers.

Modeling the curing kinetics for a modified bismaleimide resin

“…1 and 6 . To investigate the curing kinetics of the modified BMI, thermal analysis methods based on the DSC (differential scanning calorimetry) 12,13 have been used. The Perkin-Elmer Series 7 DSC was used, which is able to continuously monitor the rate and extent of reaction during isothermal curing.…”

“…[3][4][5][6][7][8][9][10][11] The addition of these constituents further adds to the already complex cure reactions that occur for the system, resulting in curing mechanisms and kinetics, which are divergent from more simple curing systems. 5,7,[12][13][14][15][16] Thermal analysis of BMI systems is also complicated by the fact that the molecular structure is rigid, and the linear portion between any two crosslink points is typically very short. Hence, the heat capacity between the glassy state and the rubbery state do not differ significantly during a DSC analysis.…”

Synthesis and processing of PMR‐15/LaRC‐TPI semi‐IPN systems

“…As the temperature increased, the proportion of anhydride increased. Possible reasons were that the LARCpoly(amic acid) reverted in part to its BTDA monomer 27, 28 or that chain scission of poly (amic acid) occurred with formation of anhydride. "…”

Effect of chemical structure on the crosslinking behavior of bismaleimides: Rheological study

“…In the studies of the crosslinking process, a chemical approach generally measures the degree of conversion of the reactive groups by using calorimetry [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and/or infrared spectroscopy [1,2,[13][14][15][16][17][18][19][20][21][22][23], among many others. Even though these methods provide useful information on the relationship between curing kinetics and molecular structure, less information is available on bulk properties of the crosslinking materials.…”