Synthesis and characterization of new thermally stable and organosoluble polyamides by direct polycondensation

Figures & data

Scheme 1 Synthesis of diacid 3.

Scheme 2 Synthesis of dicarboxylic acid 9.

Figure 1 ¹H NMR spectrum of 4,4′-bis(1,3-diphenoxypropane) dialdehyde 8.

Figure 2 FTIR spectrum of 4,4′-bis(1,3-diphenoxypropane) diacrylic acid 9.

Figure 3 ¹H NMR spectrum of 4,4′-bis(1,3-diphenoxypropane) diacrylic acid 9.

Figure 4 ¹³C NMR spectrum of 4,4′-bis(1,3-diphenoxypropane) diacrylic acid 9.

Scheme 3 Synthesis of PAs 5a–f.

Scheme 4 Synthesis of CoPAs 10a–f.

Table 1. Syntheses and some physical properties of PAs 5a–f and CoPAs 10a–f.

Diamine	Yield (%)		η inh (dL/g)^a		Color^b
	PAs 5a–f	CoPAs 10a–f	PAs 5a–f	CoPAs 10a–f	PAs 5a-f	CoPAs 10a–f
4a	91	90	0.72	0.81	W	W
4b	90	95	0.66	0.70	PC	C
4c	94	91	0.67	0.68	C	C
4d	92	89	0.61	0.78	W	PC
4e	89	92	0.58	0.69	C	W
4f	88	88	0.57	0.73	W	C
^aMeasured at a concentration of 0.5 g/dL in DMF at 25°C.^bC = Cream, PC = Pale Cream, and W = White.

Figure 5 FTIR spectrum of PA 5f.

Figure 6 ¹H NMR spectrum of PA 5a.

Figure 7 FTIR spectrum of CoPA 5a.

Figure 8 ¹H NMR spectrum of CoPA 10d.

Table 2. Solubility of PAs 5a–f and CoPAs 10a–f.

Solvent	5a	5b	5c	5d	5e	5f	10a	10b	10c	10d	10e	10f
H2SO4	++	++	++	++	++	++	++	++	++	++	++	++
DMAc	++	++	++	++	++	++	++	++	++	++	++	++
DMSO	++	++	++	++	++	++	++	++	++	++	++	++
DMF	++	++	++	++	++	++	++	++	++	++	++	++
NMP	++	++	++	++	++	++	++	++	++	++	++	++
THF	++	++	++	++	++	++	+	+	+	+	+	+
Pyridine	+	+	++	++	+	+	+	+	+	+	+	+
Cyclohexanone	+–	+–	+	+	+–	+–	+–	+–	+	+	+–	+–
CHCl3	–	–	–	–	–	–	–	–	–	–	–	–
Acetone	–	–	–	–	–	–	–	–	–	–	–	–
EtOH	–	–	–	–	–	–	–	–	–	–	–	–
MeOH	–	–	–	–	–	–	–	–	–	–	–	–
H2O	–	–	–	–	–	–	–	–	–	–	–	–
Solubility: + +: soluble at room temperature; +: soluble on heating; + –: partially soluble on heating; and –: insoluble on heating.

Table 3. Thermal behavior of PAs 5b, 5d, and 5f and CoPAs 10b, 10d, and 10f.

Polymer	T g ^a	T 5 (°C)^b	T 10 (°C)^b	Char yield^c
5b	187	340	390	31.7
5d	184	350	380	34.4
5f	190	360	390	28.8
10b	192	380	420	47.4
10d	205	390	410	47.3
10f	200	370	410	46.3
^aGlass transition temperature was recorded at a heating rate of 10 °C min^−1 in a nitrogen atmosphere.^bTemperature at which 5 or 10% weight loss was recorded by TGA at a heating rate of 10 °C min^−1 under N2.^cWeight percentage of material left after TGA analysis at a maximum temperature of 800 °C under N2.

Figure 9 TGA curves of some PAs and CoPAs.