The Crystal Structure Transition And Piezoelectric Study Of Nylon 1313

Nylon 1313 as a new type of odd-odd number long carbon chain polyamide,the research on its crystalline structure is not enough in-depth, in addition, the research on the piezoelectric property hasn’t systemly, only have a comprehensive understanding of the performance of nylon 1313, can lay the foundation for its application, therefore, in this paper we discussed the crystalline structure of nylon 1313 and the piezoelectric properties in detail.Firstly,by different preparation methods we obtained different crystal forms of nylon 1313 samples,and then by means of X-ray diffraction(XRD) and Fourier transform infrared(FT-IR) characterization methods, different crystal structure transitions were observed for samples of annealing、stretch process and solvent casting film treatment. In addition, by the help of variable temperature X-ray diffraction and in situ Fourier transform infrared characterization, we not only observed the polyamide samples of α and γ crystal structure transition in the process of heating,but also observed its Brill transition temperature changes and the Brill transformation mechanism.Through the study of nylon 1313 crystal structure transformation, we obtained the following conclusions: the γ crystal structure of nylon 1313 under the condition of annealing, isothermal crystallization can be transformed into α crystal structure, and the α crystal structure under the action of stretching or iodine, potassium iodide solution can also transform into γ crystal structure.Under variable temperature X-ray diffraction(XRD), only the α crystal structure can be observed the Brill transition phenomenon, but the Brill transition temperature(TB) is not the same, slow cooling sample of TB is 120 oC, annealed at 150 oC sample of TB is 100 oC, the sample isothermal crystallization at 135 oC,the TB is 140 oC, while the sample isothermal crystallization at 150 oC was not observed the Brill transition in front of the melt, it is illustrated that the TB of nylon 1313 has great concern with its thermal history.In addition, some specific functional groups under variable temperature infrared disappeared and the decrease in the strength of hydrogen bond show that the mechanism of Brill transition is consistent with the melting theory of methylene chain segment.The piezoelectric study of Nylon 1313 indicate that polyamide 1313 with piezoelectric, and under the condition of our experiment we got the maximum piezoelectric coefficient d33 is 5.3 PC/N, with the polarization condition is that the polarization field strength is 50 KV/mm and temperature is 70 oC, In addition, the study also found that after dealing with the tensile,the piezoelectric coefficient is greatly improved, and the piezoelectric coefficient still can maintain long-term stability, even annealed in 140 oC will not occur depolarization phenomenon, which shows that amorphous area plays a key role in the piezoelectric properties.