Patent ID: 11873584
Assignee: DEAKIN UNIVERSITY
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC D  C | IPC C  D

Claim 7:
8. The process according to claim 1, further comprising a step of determining a tension parameter for a precursor prior to forming the pre-stabilised precursor, wherein determining the tension parameter for the precursor comprises:
(a) selecting a temperature in a range of from 250° C. to 400° C. and time period for heating a precursor in a substantially oxygen-free atmosphere containing not more than 0.005% by volume of an oxygen containing molecule;
(b) applying a range of different substantially constant amounts of tension that vary by less than 5% to the precursor while heating the precursor in the substantially oxygen-free atmosphere at the selected temperature and for the selected time period;
(c) determining by Fourier transform infrared (FT-IR) spectroscopy using the equation defined in claim 1 the amount of cyclised nitrile groups (EOR (%)) formed in the precursor for each substantially constant amount of tension applied to the precursor;
(d) calculating a trend of extent of nitrile group cyclisation versus tension,
(e) identifying from the calculated trend the amounts of tension providing at least 10% nitrile group cyclisation and maximum nitrile group cyclisation; and
(f) selecting an amount of tension giving rise to at least 10% nitrile group cyclisation to pre-stabilise the precursor.