Crystallization Regulation And Controlling For The Poly(Trimethylene Terephthalate) /Polycarbonate Blends Using MWCNTs And Other Carbon Nanoparticles

Crystallization rate is the key to control the rapid processing of PTT/PC blends, but in the literatures, the research results of the crystallization of PTT/PC blends were different, in this paper, the crystallization behavior of simple two-phase structure of PTT/PC blends and its influencing factors were studied, the effect of blends composition、shear field、temperature field、processing time, and thus determine the phase morphology/phase interface on the crystallization of PTT/PC blends were studied in detail, the purpose was to explain the real reason and influencing factors of the decline of PTT/PC crystal properties. On this basis, we used MWCNTs and other carbon nanoparticles to regulate PTT/PC crystallization behavior, the mechanism and law of nanoparticles promoting the crystallization of PTT/PC were research clearly, which laid a solid theoretical and guiding basis for the preparation of excellent comprehensive performance、rapid prototyping PTT/PC blends. The specific research results as follows:1. The real reasons for the decline of PTT/PC crystal properties were the PC phase and the phase morphology/phase interface rather than the transesterification and degradation.2. We used three kinds of MWCNTs which were M5、SMC1 with Carboxyl、SMH1 with Hydroxylation to study their impacts on the crystallization of PTT/PC. The results showed: when the processing condition was 250oC、100rpm, M5、SMC1 and SMH1 had no role in promoting the crystallization of PTT/PC blends, but when the processing condition is 240oC、60rpm, M5、SMC1 and SMH1 had a significant role in promoting the crystallization of PTT/PC blends. MWCNTs which were modified by hydroxyl or carboxyl were not in favor of improving PTT crystallization. Three kinds of MWCNTs could not induce the crystallization of dispersed PTT phase.M5、SMC1 and SMH1 were grinded into nanoparticles(M5-1、SMC1-1 and SMH1-1) and the length was 50-400 nm. Their promoting effect on the crystallization of PTT/PC were significantly enhanced. With temperature and rotational speed increased, the promoting effect of SMH1-1 and SMC1-1 on the crystallization of PTT/PC was also significantly enhanced. When the PTT was dispersed phase, M5-1 and SMH1-1 showed prominent induced nucleation capability which was depended on the content and the speed.M5 was treated by acid and grinded into nanoparticles with different length: M5-21(L=10-200nm)、M5-22 and M5-23(L=10-100nm). In low temperature and low speed condition, the effect of M5-2 series on the crystallization of PTT phase was controlled by dispersion, so good dispersion of M5-2 series was more effective to promote PTT phase crystallization than appropriate increasing the content of M5-1 series. When the content of M5-2 series was the same, the promoting effect was enhanced with the decrease of particle size and the increase of content, but when the particles size decreased to a certain size, the dependence of increasing content would reduce or even disappear. With the increase of temperature and rotational speed, the promoting effect of M5-2 series on the crystallization of PTT phase was significantly increased, however, if the degree of dispersion was improved, the difference of crystallization which was caused by particle size was also weakened. When the PTT was dispersed phase, M5-2series showed prominent induced nucleation capability which was depended on the temperature and the speed. Master batch method((3 + 7) mode) could significantly improve the promotion of MWCNTs on the crystallization of PTT phase.M5 was treated by acid for 1h or 1.5h and grinded into particles with different length:M5-31、M5-32( L=10-80nm). With the same content and processing condition, the promoting effect of M5-32 on the crystallization of PTT was significantly stronger than M5-31. The promoting effect of M5-3 series PTT phase crystallization was also increased with the increase of rotational speed and dosage. The surface defects of MWCNTs after acid treatment was beneficial to the dispersion in the matrix and induce the nucleation of PTT crystallization. When the PTT was dispersed phase, M5-3 series MWCNTs could not induce PTT phase to crystallize.