THE CRYSTALLINITY OF POLYARYL ETHER ETHER KETONE .2. PEEK COMPOSITES

Measurement of the degree of crystallinity of the polymer matrix in a composite is complicated by the presence of the reinforcing additive. This is particularly the case in APC-2 in which as much as 70% can be carbon fibre. A First Law procedure, developed for determining the deg ree of crystallinity of PEEK, which involves direct measurement of the enthalpy changes associated with melting, crystallization and heat ca pacity changes, has found to be an effective method for the determinat ion of the crystallinity of the PEEK matrix. The procedure has been ap plied to carbon fibre and glass fibre PEEK composites.