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Poly(decamethylene terephthalamide) (PA10T), a bio‐based high‐performance semi‐aromatic polyamide, has been commercialized in recent years. However, there still are some weaknesses restricting its application range, such as narrow melt processing window and low ductility. In this study, we chose dodecanedioic acid (a potential bio‐based raw material) as the comonomer to prepare copolyamides [poly(decamethylene terephthalamide/decamethylene dodecanediamide), PA10T/1012] for solving these problems. The basic properties of these copolyamides were characterized by viscosity measurement, Fourier transform infrared spectrometer, proton nuclear magnetic resonance, wide‐angle X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and tensile measurement. Results show that, compared to PA10T, PA10T/1012 exhibits wider melt processing window and more outstanding elongation at break. Meanwhile, PA10T/1012 is still qualified for high temperature resistant material. Furthermore, Tg, Td,5%, Td,10%, and Td,max of PA10T/1012 show a linear dependence on 1012 content, which is helpful to design new bio‐based copolyamides for meeting the needs of various occasions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46531.

A series of 10T/10X (X = 6, 8, 10, 12, 14, 16) copolyamides was synthesized, and the thermal and mechanical properties were investigated. The effects of the lengths of alkyl chains of diacids on their resultant properties were studied, and we found that the introduction of a small amount of aliphatic diacid hardly changed the lattice parameters of the copolyamides. The T m and T c values of the 10T/10X copolyamides decreased and had a zigzag oscillation behavior as the lengths of alkyl chains on the diacids increased. A density functional theory study showed that the observed behaviors were related to the change in hydrogen bond strength and the length mismatches of the diacids in the copolymer chains. The tensile strength decreased slightly, while the elongation at break increased significantly with an increase in the chain length of the aliphatic diacid; further, the notched impact strength decreased but was still higher than PA10T.

Poly (decamethylene terephthalamide) (PA10T) is a kind of engineering plastics with high strength and high modulus, but one of its disadvantages is its low elongation at break. In order to improve the flexibility of PA10T, one aliphatic comonomer with a long alkyl chain is introduced to the molecular chain of PA10T. Then long chain semiaromatic copolyamides 10T/1014 were synthesized with different contents of 1014 units by polycondensation reaction of 1,10-diaminodecane, terephthalic acid and 1,12-dodecanedicarboxylic acid in deionized water. The intrinsic viscosities of the resultant polyamides ranged from 0.90 to 1.03 dL/g were obtained. The chemical and crystal structures of the copolymers were characterized by FTIR, 1H-NMR and WAXD. These copolyamides exhibited outstanding thermal properties with melting points range of 306–295 °C and degradation temperatures range of 479–472 °C at maximum degradation rate, and also have a wider processing window than PA10T. The tensile strength of PA10T/1014 copolymers decreased gradually from 80.02 to 72.95 MPa as the content of 1014 units increasing from 5 to 20 mol %, while the elongation at break increased significantly from 57 to 150%. The moisture content of 10T/1014 copolyamides decreased with increasing the 1014 unit contents. It suggests that 10T/1014 copolyamides could be a kind of promising heat-resistant engineering thermoplastic in the future applications.

A series new biobased polyamide 10T-co-56 are synthesized with various comonomer composition by one-pot polycondensation reaction and investigated their structures, crystalline and melting behavior by using 1H-NMR spectroscopy, wide angle...

A novel silicone monomer modified poly(decamethylene terephthalamide) PA10T is synthesized from 1,10‐decanediamine (DMD), terephthalic acid, and 1,3‐bis(3‐aminopropyl)tetramethyldisiloxane (DS2). The chemical structure of the product is characterized using Fourier transform infrared spectrometry and nuclear magnetic resonance. The crystallization behavior, thermal properties, and mechanical properties of PA10T are also analyzed. Copolymerization of PA10T with DS2 results in reduced crystallinity and thermal properties, but to a lesser extent than when PA10T is modified with aliphatic polyamide. With increased DS2 content, the tensile strength of PA10T decreases gradually, while the elongation at break and impact strength increase significantly, indicating that the toughness of PA10T has been improved.

Aiming at biobased semiaromatic polyamides with high performance from furan derivatives and studying the effect of the ratio of furan rings to benzene rings on the properties of polyamide, a series of poly­(decamethylene terephthalamide/decamethylene 2,5-furandicarboxamide) copolyamides (PA10T/10Fs) with the furan ring content ranging from 0 to 100 mol % were prepared from 2,5-furandicarboxylic acid derivatives, terephthalic acid, and 1,10-decanediamine via a two-step polymerization method. Their molecular weight, intrinsic viscosity, composition, and chemical structure were determined using an Ubbelohde viscometer, gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance. The properties of PA10T/10Fs were characterized by X-ray diffraction, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, thermal deformation temperature measurement, heat deflection temperature measurement, tensile measurement, notched impact test, and water absorption measurements. The results showed that the target products had been successfully prepared, the PA10T/10Fs with a 10F content of no more than 20 mol % were crystalline, and these copolyamides exhibited comparable heat resistance and elevated tensile strength and elongation at break with those of the PA10T homopolymer. With the further increase of the 10F content, PA10T/10Fs turned amorphous gradually, together with improved transparency, indicating that the intermolecular hydrogen bond was effectively suppressed, which was also supported by density functional theory (DFT) calculations, and the heat resistance and tensile strength decreased slightly, but the elongation at break increased; moreover, the increased furan ring content in PA10T/10Fs resulted in a lower notched impact strength and increased water absorption.