Novel heat resistant nanostructure poly(amide–imide)s containing new TMA-based diacid via conventional polycondensation reaction in an ionic green medium: synthesis, morphology, and thermal properties

Figures & data

Scheme 1 Synthesis of TMA containing diacid monomer.

Figure 1 ¹H-NMR (400 MHz) spectrum of obtained diacid and PAI5b in DMSO-d ₆.

Figure 2 FT-IR (KBr) spectrum of synthesized diacid monomer.

Scheme 2 Polycondensation reactions of MCDEA-based dicarboxylic acid with different diamines.

Table 1. Synthesis and some physical properties of PAI5a–PAI5d prepared in TBAB.

Diamine	Polymer^a	Yield (%)	η ^b (dL/g)	Color
4a	PAI5a	90	0.48	Pale Yellow
4b	PAI5b	91	0.45	Orange
4c	PAI5c	93	0.40	Yellow
4d	PAI5d	89	0.44	Yellow
^aPolymers were precipitated in methanol.^bMeasured at a concentration of 0.5 g/dL in DMF at 25 ^oC.

Figure 3 The infrared spectra of PAI5c.

Figure 4 XRD patterns of PEI5a.

Figure 5 FE-SEM micrographs of PAI5a (a, b), PAI5c (c, d), and PAI5d (e, f) before ultrasonic irradiation.

Figure 6 FE-SEM micrographs of PAI5a (a’, b’), PAI5c (c’, d’), and PAI5d (e’, f’) after ultrasonic irradiation.

Table 2. Thermal properties of PAIs.

Polymer	Decomposition temperature (^oC)		Char yield^c (%)	LOI^d
	T 5 ^a	T 10 ^b
PAI5a	342	369	34.8	31.4
PAI5b	357	405	42.8	34.6
^aTemperature at which 5% weight loss was recorded by TGA at heating rate of 20 ^oC/min under a nitrogen atmosphere.^bTemperature at which 10% weight loss was recorded by TGA at heating rate of 20 ^oC/min under a nitrogen atmosphere.^cWeight percentage of material left undecomposed after TGA analysis at a temperature of 800 ^oC under a nitrogen atmosphere.^dLimiting oxygen index (LOI) evaluating char yield at 800 ^oC.

Figure 7 TGA thermograms of resulting PAI5a and PAI5b under a nitrogen atmosphere at heating rate of 20 ^°C/min.

Figure 8 UV/vis spectra of synthesized polymers.