Infrared spectroscopic determination of the kinetic data of the polymerization of aliphatic bismaleimides

Abstract

SynopsisBismaleimides polymerize a t elevated temperatures, forming highly crosslinked, high temperature-resistant polymers. From the decrease of the v(H-C=) band at 3100 cm-1, rate constants and activation energies of the polymerization of four homologous aliphatic bismaleimides were determined. Up to a 20-30% conversion, the polymerization is pseudofirst order. An almost linear correlation between the activation energy and the number of methylene groups in the sequence between the maleimide residues was found. ZusammenfassungBismaleinimide polymerisieren spontan bei hoheren Temperaturen unter Bildung vernetzter, hochtemperaturbestandiger Polymerer. Aus der Abnahme der Extinktion der v(H--C=>Bande bei 3100 em-' wiihrend der Polymerisation wurden Geschwindigkeitskonstante und Aktivierungsenergie der Polymerisation von vier homologen aliphatischen Bismaleinimiden bestimmt. Bis zu einem Umsatz von 20-30% ist die Polymerisation pseudo-erster Ordnung. Zwischen der Aktivierungsenergie und der Zahl der Methylengruppen in der Brucke zwischen den Maleinimideinheiten wurde in dem untersuchten Bereich eine nahezu lineare Abhangigkeit gefunden. RbUIllCLes bis-imides mal6iques polym6risent spontanement h hautes temperatures avec la formation de pclymbres entrelac6s, qui sont resistants A des temp6ratures Blevees. A l'aide la diminuation de l'extinction de la bande de valence H-C-A 3100 cm-l, la constante de vitesse ainsi que 1'6nergie d'activation de quatre homologues aliphatiques bisimides mal6iques ont BtB d6terminCes pendant la polymerisation. La reaction, pendant laquelle 20 L 30 pour cent des bis-imides maleiques se sont polymeris6s, est "pseudo premier ordre." Une relation L peu prbs lin6aire a ete trouvee-dans le domaine ou les mesures ont 6tk effectu6es-entre l'energie d'activation et le nombre de groupes methylbne dans le pont entre les unites des imides malkiques.

Isothermal transformation of dynamic DSC curves for thermosetting polymers in curing kinetics analysis

“…ld shows that the reaction order for HMBMI homopolymerization is close to 1. This agrees fully with the results reported in [16], where E is found to be 140.5 kJ/mol (compare with the values listed in the Table). Once ITDC has been performed, it is possible to calculate the pre-exponential factor: A = 2.15 " 1013 rain -1 for HMBMI.…”

“…The first (EDA) comprises epoxy resin ED-22, iso-methyltetrahydrophthalic anhydride (iso-MTPHA) as a curing agent and naphthylene benzimidazole (NBI) as a eatalyst, in the mass ratio 100 : 80 : 0.5. The seeond is N,N'-hexamethylenebismaleimide (HMBMI), the homopolymerization of which has been well studied by IR spectroscopy [16].…”

Synthesis and Characterization of a POSS-Maleimide Precursor for Hybrid Nanocomposites

“…In Figure 1, showing the IR spectra of OMPS, DDM and OMPS/DDM systems, the disappearance of the peak at 3100 cm -1 , corresponding to the maleimide double bond in OMPS, confirms the existence of the Michael addition reaction with the amino group of DDM and the formation of an aspartimide [19]. A previous kinetic study of the thermal polymerization of aryl bis-maleimides and bis-citraconimides confirms that the Michael addition reaction occurs through an ionic mechanism, which proceeds much more quickly than the BMI homopolymerization [20][21][22][23][24][25].…”

Epoxy Resin Containing Octamaleimidophenyl Polyhedral Oligomeric Silsesquioxane

“…The synthetic method used in the present work is slightly different from that reported by Krishnan et al [37] In this work, sodium acetate (NaAc) was used as the catalyst to facilitate the imidization. [38][39][40][41] Typically, in a 250 ml three-necked flask equipped with a magnetic stirrer and a reflux condenser, maleic anhydride (1.359 g, 13.872 mmol) dissolved in 100 ml anhydrous DMF was charged at 80 8C with vigorous stirring and then OapPOSS [(H 2 NC 6 H 4 ) 8 Si 8 O 12 ] (2.0 g, 1.734 mmol) that was pre-dissolved in 50 ml anhydrous DMF was dropped to the system within 30 min in nitrogen atmosphere. The reaction was allowed to be carried out at 80 8C for 24 h and then both sodium acetate tetrahydrate (NaAc Á 4H 2 O) (0.1180 g, 0.867 mmol) and acetic anhydride (2.124 g, 20.808 mmol) were added.…”