Chain Extension Reaction of PA1010 by 2,2’-Bis(2-oxazoline)
Baohua Guo, Zhenyu Qian, Jianzhong Shi, Jun Xu
Institute of Polymer Science and Engineering, Department of Chemical Engineering,Tsinghua University
China

Keywords: PA1010, Chain Extension, Crystallization

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The reaction behavior of 2,2’-bis(2-oxazoline) (BOZ) has been studied to evaluate its coupling effects as the
chain extender for polyaimde1010 (PA1010). It has been observed that the torque of PA1010 melt, which is
recorded by a Haake mixer, increased dramatically with the increase of reaction time. However, a slight decrease of torque could be found in the later stage of the chain-extension reaction, probably due to degradation of the resultant. The maximal torque of PA1010 melt also increased with increasing the content of BOZ. However, addition of excess amount of BOZ led to more blocking reaction, not coupling reaction, indicating that the PA1010 of not-so-much-increased molecular weight but much-decreased carboxyl concentration would be produced. The PA1010, with end carboxyl group concentration of 52.8 eq/10 6 g and melt torque of 0.7 Nm at 240 with a rotor speed of 40rpm, was added 0.84wt% BOZ to carry out a chain extension reaction. The resultant PA1010 having end carboxyl concentration of 8.2 eq/10 6 g and melt torque of 3.3Nm was achieved, after an optimal reaction time. What’s more, end amide concentration kept approximately constant and no crosslinking would accompany with the chain-extension reaction. The effect of temperature on the chain extension reaction rate accords with the Arrhenius exponential formula. In addition to temperature, the shear rate also has some effectson the chain-extension rate, which indicated that the higher the shear rate, the higher the reaction rate. By the analysis of non-isothermal crystallization kinetics, the DSC data of PA1010 were processed. The results show that there is a distinct different distribution of crystallization rate between chain-extended PA1010 and non-chain-extended PA1010.