A semicrystalline polyimide was synthesized from 3

3'

4

4'-biphenyltetracarboxylic dianhydride(s-BPDA)/1

3-bis-(4-aminophenoxy)benzene(TPER)/phthalic anhydride(PA).According to the crystallization exothermic peaks obtained from differential scanning calorimetry (DSC)when cooling from melt at 2

5

10

20 K/min

respectively

the method of Jeziorny

Ozawa and an approach proposed by MO Zhishen were applied to study the non-isothermal crystallization behaviour of this polyimide.The results suggested that s-BPDA/TPER/PA was a very special system

the onset crystallization temperatures were almost the same at different cooling rates.The apparent Avrami exponent n obtained by the Jeziorny method was 2.4 and then changed to 3.5 when cooling rate reached 20 K/min

indicating the mechanism of nucleation or the way of growth have changed.Besides

the kinetic parameter Zc increased with the increase of the cooling rate.Whereas deviations and fluctuations occurred in the later stage due to the secondary crystallization.The Ozawa method was also limited in obtaining the reliable kinetic parameters because of the substantial curvatures in the Ozawa plots.However

the approach proposed by Mo Zhishen appeared applicable due to the better linear relation

according to the new parameter a

the relationship between Ozawa exponent m and apparent Avrami exponent n was confirmed (n/m =1.3)and exact values of m were obtained.Finally

Kissinger method was used to get the value of the crystallization activation energy E

about -936 kJ/mol

which meant a fast nucleation rate of this system.