High Performance Polymers, 2nd Edition

48 HIGH PERFORMANCE POLYMERS

Table 2.2 Melting and Glass Transition

Temperatures of Substituted PPXs [18,

49]

Substituent T

m

(

◦

C) T

g

(

◦

C)

– 420

Phenyl 106

Benzyl 51

Ethylphenyl 32 137

Propylphenyl 5

Butylphenyl −3 86

Pentylphenyl −8

tert

-Butyl 177

Norbornenyl 136

Trifluoromethyl 89

enhances the glass transitiontemperature upto 294

◦

C.

Further, a low dielectric constant of 2.5 and a very

low dielectric loss tan δ of 0.0004 at 1 GHz are

observed [50].

Alkyl-aryl-substituted PPX is soluble at ambient

temperatures and has a comparatively low-melting

temperature. The glass transition temperatures of

alkylphenyl-substituted PPX are shown in Table 2.2.

A norbornenyl-substituted ...