Synthesis And Characterization Of Semiaromatic Transparent Polyamide 10I/10T

The issue in this dissertation was proceeded with the cooperation of Polymer Instiute of North University of China and Dongguan XinNuo Rubber Industrial Co.Ltd. A new kind of semi-aromatic transparent polyamide 10I/10T was systhesized by using the monomer of decanediamine, isophthalic acid(IPA) and terephthalic acid (PTA) as original materials,and the performance has been tested 。Transparent polyamide 101 was synthesized with the monomer of decanediamine, isophthalic acid through the process of melt polycondensation. In the synthesis process, the temperature for the pre-polymerization reaction is optimized at about 210℃ and the pressure is maintained at 1.6 MPa reaction for 1 h. the final polymerization temperature is at 236℃ and the atmosphere pressure is kept for 2 h. Finally, the viscosity is increased by vacuum pumping and the products are extracted by pressing. The color difference b* value of the polymerization product was reduced from 2.21 to 1.54 by adding antioxidants. It showed that the antioxidant can improve the yellowing of polymers. The added amount of SEED and B1036 was 0.1%. With the addition of 0.1% nucleating agent CAV102, the surface of the as-prepared transparent PA 10I will be smoother and glossier.The transparent PA10I/10T was synthesized with the monomer of decanediamine, isophthalic acid and terephthalic acid via the process of melt poly-condensation. When the content of PTA increases from Oto 0.45 mol, the final polymerization temperature should change from 236℃ to 255℃. The transmittance of the as-prepared transparent PA10I/10T is about 90%.While the transmittance decreases sharply with the addition of PTA and the amount of PTA should not be more than 0.30 mol. Transparent PA10I/10T under a polarizing microscope showed the dark field, there was no clear highlights and extinction black cross. There is no any phase transition absorption peak in the DSC curve of the transparent PA10I/10T but a glass transition, which indicates that the as-obtained transparent PA10I/10T is a kind of amorphous polymers.The thermal properties of transparent PA 101 and transparent PA10I/10T were testing by DSC, TGA and DMA et al. When the addition amount of PTA ranges from 0 to 0.3 mol, there are some impacts on the thermal properties of as-prepared transparent PA10I/10T. For example, the glass transition temperature is increased from 103.0℃ to 115.3 ℃, the heat distortion temperature is improved from 88.0℃ to 95.8℃. The temperature of the initial decomposition of the as-prepared transparent PA10I/10T was demonstrated to be above 400℃. According to the Coats-Redfern integral method, the thermal degradation activation energy respectively were 621.01 kJ·mol-1、583.69 kJ·mol-1、614.68 kJ·mol-1、602.80 kJ·mol-1、603.00 kJ·mol-1, which all manifest that the as-prepared transparent PA10I/10T is of great thermal stability.The as-prepared transparent PA10I/10T is proved to be pseudoplastic fluid, which is measured by capillary rheometer. The apparent viscosity will reduce with the increase of the shear stress or the shear rate, which presents the phenomenon of "shear thinning". When increasing the temperature, the non-newtonian index n tends to reduce. The viscous flow activation energy decreases with the increase of shear rate, which indicates that the sensitivity of the apparent viscosity to the temperature is weaken.The PTA also has influences on the mechanical properties of the as-obtained transparent PA10I/10T. When the addition amount of PTA increases from 0 mol to 0.3 mol, the ensile strength and the elongation at break are enhanced, while the flexural strength and the flexural modulus all decrease. The notched impact strength increased and then decreased after. The water absorption is at about 0.2%, which implies that the as-obtained transparent PA10I/10T has excellent solvent resistance.When compared to the PA 10I, the transmittance and the notched impact strength of the as-prepared transparent PA10I/DMDCI and PA10I/PACMI are reduced, while the thermal performance, the tensile strength, the flexural strength and the flexural modulus are all improved.