Semicrystalline DABP-BTDA polyimide modified by fullerenes for wear protection - Polyimides and Other High Temperature Polymers - page 503

Table 1.
Mechanical characteristics of BTDA-DABP PI moldings

BTDA-DABP PI E

at 20°С, МPа

ε max ,
%

σ b
at 20°С, МPа

Semi-crystalline
sample (chemical imidization)

118 2150 5.5

Semi-crystalline
sample (thermal imidization)

9 820 1.1

σ b - bending strength, E - Young's modulus, ε max - failure strain.

Table 2.
Melting temperatures and enthalpies of BTDA-DABP PI-fullerene compositions with fullerene in-
troduced in different stages of PI synthesis

Т g , о С Т m. , о С

BTDA-DABP PI-Fullerene composition ∆Н, J/g

Sample 1 - obtained by method 1 245 285 28.0
Sample 2 - obtained by method 2 237 270 17.2
Sample 2' 237 290 9.0
Sample 3 - obtained by method 3 - 273 29.3
Sample 4 - obtained by method 4 237 282 13.7
Sample 5 (without fullerene) 250 290 28.0
Sample 2′ was prepared under conditions similar to those for sample 2 but at the end of the syn-
thesis, phthalic anhydride was added.

Table 3.
Thermal stability characteristics of BTDA-DABP PI-fullerene compositions

BTDA DABP PI-Fullerene composition τ 0 (°C) τ 5 (°C) τ 10 (°C)

Sample 1 - obtained by method 1 465 568 606

Sample 2 - obtained by method 2 480 585 620

Sample 2′ 486 550 570

Sample 3 - obtained by method 3 470 555 575

Sample 4 - obtained by method 4 480 550 575

Sample 5 (without fullerene) 553

450 532

Sample 2′ was prepared under conditions similar to those for sample 2 but at the end of the syn-
thesis, phthalic anhydride was added.

The molding based on polyimide-fullerene compositions obtained by method 2 is
also the best with respect to the second tribological characteristic: wear (Fig. 3). Note
that the introduction of fullerene into the monomer, in contrast to the case of its intro-
duction during the stages of PAA synthesis, leads to a considerable decrease in the
wear of the molding (Fig. 3, curve 2). For molding without fullerenes, the wear (Fig.
3, curve 5) is much higher than for moldings obtained by method 2 (Fig. 3, curve 2).