Thermal and dielectric properties of newly developed L-tryptophan-based optically active polyimide and its POSS nanocomposites

Figures & data

Figure 1. FTIR spectra of L-tryptophan, L-tryptophan methyl ester, MDNP and MDAP.

Figure 2. ¹H-NMR spectra of the precursor MDNP and the monomer MDAP.

Figure 3. ¹³C-NMR spectra of the precursor MDNP and the monomer MDAP.

Figure 4. FT-IR spectrum of PAA, MDAP/BTDA–PI, POSS and MDAP/BTDA–PI/POSS (3 wt%) nanocomposite.

Figure 5. SEM Images of (a) neat MDAP/BTDA–PI (b) MDAP/BTDA–PI/POSS (1 wt%) (c) MDAP/BTDA–PI/POSS (3 wt%) (d) MDAP/BTDA–PI/POSS (5 wt%).

Figure 6. TEM Images of (a) MDAP/BTDA–PI/POSS (3 wt%) (b) MDAP/BTDA–PI/POSS (5 wt%).

Figure 7. AFM Images of (a) MDAP/BTDA–PI/POSS (1 wt%) (b) MDAP/BTDA–PI/POSS (3 wt%) (c) MDAP/BTDA–PI/POSS (5 wt%).

Figure 8. DSC curves of (a) neat MDAP/BTDA–PI (b) MDAP/BTDA–PI/POSS (1 wt%) (c) MDAP/BTDA–PI/POSS (3 wt%) (d) MDAP/BTDA–PI/POSS (5 wt%).

Figure 9. TGA curves of (a) neat MDAP/BTDA–PI (b) MDAP/BTDA–PI/POSS (1 wt%) (c) MDAP/BTDA–PI/POSS (3 wt%) (d) MDAP/BTDA–PI/POSS (5 wt%).

Figure 10. Dielectric constant of (a) neat MDAP/BTDA–PI (b) MDAP/BTDA–PI/POSS (1 wt%) (c) MDAP/BTDA–PI/POSS (3 wt%) and (d) MDAP/BTDA–PI/POSS (5 wt%).

Scheme 1. Synthesis of the diamine monomer MDAP.

Scheme 2. Synthesis of polyimide.

Scheme 3. Synthesis of polyimide/POSS nanocomposites.

Table 1. TGA, DSC and dielectric constant values of neat polyimide and PI/POSS nanocomposites.

Properties	Neat PI	PI/OAPS(1%)	PI/OAPS (3%)	PI/OAPS (5%)
Ti (°C)	315.0	330.0	346.6	368.5
Tg (°C)	222.5	230.0	238.3	250.1
T10%	402.4	425.8	452.0	470.5
Residue%	31.2	33.5	35.4	36.7
LOI%	29.9	30.9	31.6	32.1
Dielectric constant	3.5	2.9	2.5	2.1