关键词: 生物基, PA11, 可纺性, 流变性能, 力学性能

Abstract: Bio-based polyamide 11 (PA11) is a kind of bio-based polymer, which is synthesized by stepwise polymerization of ω-aminoundecanoic acid, the pyrolysis product of castor oil. At present, PA11 is mainly used in the field of engineering plastics, and it is rarely involved in the fiber field. With the launch of China's "double carbon" goal and the widespread popularization of environmental awareness, increasing attention has been paid to the green carbon sequestration benefits of bio-based PA11 in the field of chemical fibers, and the development of corresponding fiber products has become an important trend. However, there are few reports on PA11 spinning. The preparation of PA11 raw material spinning grade chips is not yet mature, and the spinning process of PA11 still lacks theoretical guidance. At present, the research on PA11 spinning at home and abroad mainly remains at the laboratory stage, and most of them focus on the mechanical properties, crystallization properties and rheological properties of the materials.
PA11 is widely used for its excellent comprehensive performance. The brittle temperature of PA11 is -70 °C, maintaining good toughness even at low temperature. PA11 exhibits good corrosion resistance to oil, alkali, salt solution, etc., and also possesses a certain degree of corrosion resistance to acid. In China, PA11 is mainly applied in the automotive industry, accounting for 70% of the total usage of PA11 materials. It is primarily used as fuel lines and brake pipes in automobiles. Its excellent chemical resistance, low-temperature performance, and dimensional stability make it widely used in anti-vibration oil pipes, hoses, and other applications. It can also be applied to low-temperature cable sheaths and defense mechanical components.
To explore the spinnability of bio-based PA11, two kinds of PA11 chips with different melt indexes were selected, and their relative viscosity, chemical structure, thermal properties and melt rheology were analyzed by automatic viscosity detector, Fourier transform infrared spectrometer, nuclear magnetic resonance hydrogen spectrometer, differential scanning calorimeter, thermogravimetric analyzer, melt flow rate meter and rotary rheometer. The drafting silk was prepared by adjusting the drafting ratio (2–5 times) and drafting temperature (60–100 ℃), and the tensile fracture experiment was carried out by electronic single yarn strength machine. The results showed that the relative viscosity of low melt index PA11-A and high melt index PA11-B were 2.85 and 2.68, respectively, and their chemical structures were similar. The melting point and thermal crystallization temperature of PA11-A were 181.3 ℃ and 123.6 ℃, respectively, while those of PA11-B were 185.1 ℃ and 113.1 ℃, respectively. Compared with PA11-A, PA11-B had better thermal stability. With the increase of temperature, the melt index of both slices increased, and the increase of PA11-B was greater. The optimum spinning temperatures of PA11-A and PA11-B were 250 ℃ and 230 ℃, respectively and the tensile mechanical properties of PA11-B draft yarn were better than those of PA11-A. This study provides important reference for PA11 spinning process.

Key words: nio-based, PA11, spinnability, rheological properties, mechanical property