Polyimides from Characteristic Monomers

The solubility of these pol5dmides is shown in Table 7.2. Pl-(s-BPDA/4,4 -ODA) was almost insoluble in any aprotic solvents. 

This order of the Tg values is rationalized in terms of the steric restriction of internal rotation around the biphenyl linkages. The restriction of internal rotation around the biphenyl linkages increases in the order of s-BPDA a-BPDA i-BPDA. Table 7.3 shows the properties of polyimides from BPDA. In contrast to those of PI-(BPDA/4,4 -ODA), the Tg values of PI-(s-BPDA/3,3 -ODA), PI-(a-BPDA/3,3 -ODA) and PI-(i-BPDA/3,3 -ODA) from 3,3 -ODA were 243°C, 245°C and 246°C, respectively those of PI-(BPDA/ 3,3 -ODA) were almost constant. The independence of the Tg is 

The CTE values for polyimides from PDA were lower than those of polyimides from 4,4 -ODA, and that of PT(s-BPDA/PDA) (12 ppmK ) was lower than that of PI-(a-BPDA/PDA) (58 ppmK-, due to the rigid linear structure (Table 7.3). PI-(i-BPDA/PDA) was not obtained as a film. 

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This chapter introduces the synthetic methods for polyimides and the relationship between their structures and properties. In order to show the remarkable effects of pol)dmide structures on their properties, the properties of polyimides from characteristic monomers are mainly described. 

Recently Russian workers reported the kinetic and thermodynamic characteristics of thermal polycondensation of the salt monomers derived from some diamines and benzophenonetetracarboxylic acid half dimethyl ester leading directly to polyimides from the viewpoint of the preparation of polyimide-based advanced composite materials (Eq. 4, R =methyl) [9-12]. 

Copolymerization of the Al-(hydroxyphenyl)maleimides with other monomers can produce polyimides with characteristics different from the homopolymer of either monomer. This has been utilized by Chiang and Lu , who claimed that useful physical characteristics are exhibited by the copolymer of Af-(hydroxyphenyl)maleimide with p-trimethylsilylstyrene (TMMS). Polyimide residue of the copolymer contributes... 

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