A bio-based polyamide elastomer fiber and a preparation method and application thereof

Abstract

The application belongs to the technical field of bio-based polymer materials, and particularly relates to a bio-based polyamide elastomer fiber and a preparation method and application thereof. The bio-based polyamide elastomer fiber provided by the application comprises an elastomer and nanocellulose. The elastomer comprises hard segment polymers and soft segment polymers arranged alternately. The hard segment is a bio-based polyamide prepolymer. The soft segment is a bio-based polytrimethylene ether glycol. The elastomer and the nanocellulose are dynamically crosslinked. The hard segment polymer has a structure shown in formula I. The number average molecular weight of the hard segment polymer is 1000-5000 g / mol. The mass content of the hard segment polymer in the elastomer is 10%-50%. The bio-based polyamide elastomer fiber provided by the application has good mechanical properties and recovery capacity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bio-based polymer materials, and particularly relates to a bio-based polyamide elastomer fiber and a preparation method and application thereof. BACKGROUND

[0002] Elastomer fibers play a key role in the fields of textiles and clothing, medical treatment and intelligent materials (such as flexible sensors) due to their excellent tensile properties and recovery ability. Traditional elastomer fibers are mainly prepared by crosslinking petroleum-based polyether or polyester polyols with isocyanate, and the production process is accompanied by problems of toxic monomer residues and high energy consumption, and the waste is difficult to naturally degrade, which aggravates the environmental burden.

[0003] As a kind of polymer material with great application prospect, bio-based polyamide elastomers have made breakthroughs in the development of new monomers and preparation technologies, but still face many challenges in practical application. For example, the bio-based polyamide elastomer designed by using polyamide 1010 (PA1010) as a hard segment and polytrimethylene glycol ether (PO3G) as a soft segment still faces the problem that the phase separation behavior of the PA1010 hard segment and the PO3G soft segment is difficult to control, resulting in insufficient mechanical properties and elastic recovery ability. SUMMARY

[0004] The purpose of the present application is to provide a bio-based polyamide elastomer fiber and a preparation method and application thereof. The bio-based polyamide elastomer fiber provided by the present application has good mechanical properties and recovery ability.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] The present application provides a bio-based polyamide elastomer fiber, which comprises an elastomer and nanocellulose; the elastomer comprises alternately arranged hard segment polymers and soft segment polymers; the hard segment polymers are bio-based polyamide prepolymers; the soft segment polymers are bio-based polytrimethylene ether glycols; and the elastomer and nanocellulose are dynamically crosslinked.

[0007] The hard segment polymers have the structure shown in Formula I;

[0008]

[0009] The number average molecular weight of the hard segment polymers is 1000-5000 g / mol.

[0010] The mass fraction of the hard segment polymers in the elastomer is 10%-50%.

[0011] Preferably, the mass fraction of the soft segment polymers in the elastomer is 50%-90%, and the number average molecular weight of the soft segment polymers is 2000 g / mol.

[0012] Preferably, the mass content of the elastomer in the bio-based polyamide elastomer fiber is ≥ 90%; the number average molecular weight of the elastomer is 20000-30000 g / mol.

[0013] The application provides a preparation method of the bio-based polyamide elastomer fiber.

[0014] (1) mixing decamethylenediamine, sebacic acid, water and a polycondensation catalyst to perform polycondensation reaction to obtain a bio-based polyamide prepolymer; the decamethylenediamine and the sebacic acid are derived from castor oil;

[0015] (2) mixing the bio-based polyamide prepolymer, bio-based polytrimethylene ether glycol, water and a titanium catalyst to perform block polymerization to obtain a copolymer with a block structure in which soft segments and hard segments are arranged alternately;

[0016] (3) mixing the copolymer and nanocellulose, and then performing extrusion and spinning in sequence, and then performing drawing and heat setting in sequence on the obtained as-spun fiber to obtain the bio-based polyamide elastomer fiber.

[0017] Preferably, the polycondensation reaction is performed under the condition of a polycondensation catalyst, and the polycondensation catalyst comprises sodium hypophosphite and / or sodium hypophosphorous acid;

[0018] The molar ratio of the decamethylenediamine to the sebacic acid is 0.7-0.95:1.0.

[0019] Preferably, the extrusion region is divided into a pre-melt conveying zone, a dynamic crosslinking reaction zone, a micro-phase homogenization zone and a steady-state rheological control zone; the temperature of the pre-melt conveying zone is 180-200℃; the temperature of the dynamic crosslinking reaction zone is 200-210℃; the temperature of the micro-phase homogenization zone is 210-230℃; and the temperature of the steady-state rheological control zone is 230-250℃.

[0020] The temperature of the spinning is 230-250℃.

[0021] Preferably, the drawing comprises primary drawing and secondary drawing performed in sequence; the temperature of the primary drawing is 80-100℃, the drawing ratio of the primary drawing is 2.8-3.2 times, the temperature of the secondary drawing is 160-180℃; and the drawing ratio of the secondary drawing is 1.2-1.5 times.

[0022] Preferably, the heat setting temperature is 180-200℃.

[0023] Preferably, the block polymerization comprises preliminary block polymerization and final block polymerization performed in sequence.

[0024] The temperature of the preliminary block polymerization is 210-230 DEG C, the pressure is 0.1-0.3 MPa, and the time is 1.5-3.0 h.

[0025] The final block polymerization is performed under vacuum, the temperature of the final block polymerization is 240-250 DEG C, and the time is 1.5-3.0 h.

[0026] The application provides application of the bio-based polyamide elastomer fiber prepared by the preparation method in biomedicine, intelligent sensing or sports clothing.

[0027] The application provides a bio-based polyamide elastomer fiber, which comprises an elastomer and nanocellulose; the elastomer comprises alternately arranged hard segment polymers and soft segment polymers; the hard segment polymers are bio-based polyamide prepolymer; the soft segment polymers are bio-based polytrimethylene ether glycol; the elastomer and the nanocellulose are dynamically crosslinked; the hard segment polymers have the structure shown in formula I.

[0028]

[0029] The number average molecular weight of the hard segment polymers is 1000-5000 g / mol.

[0030] The mass percentage of the hard segment polymers in the elastomer is 10%-50%.

[0031] The bio-based polyamide elastomer fiber provided by the application is alternately arranged by bio-based polyamide prepolymer and bio-based polytrimethylene ether glycol (PO3G), and the two are connected by chemical bonds to form a rigid-flexible molecular chain structure. Meanwhile, nanocellulose (CNC) is used as a dynamic crosslinking agent to realize precise regulation of the interaction between molecular chains. The acid-terminated polyamide prepolymer is designed to control the molecular weight of the hard segment, and the ratio of the soft segment and the hard segment is adjusted, so that the hard segment ordered crystallization region and the soft segment amorphous region form a controllable microphase separation structure, and the dispersion of nanocellulose enhances the interaction of the two-phase interface, giving the material multiple regulation in the structural hierarchy. The structural design breaks through the traditional elastomer single crosslinking or simple blending mode, and through the synergistic innovation of bio-based block sequence and dynamic crosslinking network, a new path is provided for the structural design of high-performance elastomers.

[0032] The data of the embodiment show that the bio-based polyamide elastomer fiber provided by the application has a breaking strength of 2.8-4.0 cN / dtex and an elongation at break of 450-600%. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative effort.

[0034] Figure 1 Infrared spectrum of the bio-based polyamide prepolymer in Example 1. DETAILED DESCRIPTION

[0035] The present application provides a bio-based polyamide elastomer fiber, comprising an elastomer and nanocellulose; the elastomer comprises hard segment polymers and soft segment polymers arranged alternately; the hard segment polymers are bio-based polyamide prepolymers; the soft segment polymers are bio-based polytrimethylene ether glycols; the elastomer and nanocellulose are dynamically cross-linked;

[0036] The hard segment polymers have a structure shown in Formula I;

[0037]

[0038] The number average molecular weight of the hard segment polymers is 1000-5000 g / mol; the mass content of the hard segment polymers in the elastomer is 10%-50%.

[0039] As an embodiment of the present application, the number average molecular weight of the hard segment polymers is 1000-5000 g / mol; the molar ratio of methylene groups to amide groups is 18:1.

[0040] As an embodiment of the present application, the mass content of the hard segment polymers in the elastomer is 10%-50%, specifically, it can be 10%, 20%, 30%, 40% or 50%, and the mass content of the soft segment polymers can be 50%-90%, specifically, it can be 90%, 80%, 70%, 60% or 50%. As an embodiment of the present application, the number average molecular weight of the elastomer is 20000-30000 g / mol. As an embodiment of the present application, the melt index of the elastomer is 15-25 g / 10 min at 190℃.

[0041] The bio-based polyamide elastomer fiber of the present application determines the critical conditions (phase separation driving force) of microphase separation and phase deformation through the molecular weight and proportion of hard segments, and optimizes the microphase separation structure by precisely adjusting the two parameters, thereby regulating the mechanical properties and elastic recovery characteristics of the material.

[0042] As an embodiment of the present application, the mass content of the elastomer in the bio-based polyamide elastomer fiber is ≥90%.

[0043] As an embodiment of the present application, the bio-based polyamide elastomer fiber can have a breaking strength of 2.8-4.0 cN / dtex, and an elongation at break of 450-600%.

[0044] As an embodiment of the present application, the bio-based polyamide elastomer fiber can have an intrinsic viscosity of 1.2-1.4 dL / g, a tensile strength of 35-45 MPa, and an elastic retention rate of 80-90%.

[0045] The present application also provides a preparation method of the bio-based polyamide elastomer fiber as described above, comprising the following steps:

[0046] (1) mixing decanediamine, sebacic acid, water and a polycondensation catalyst to perform a polycondensation reaction, to obtain a bio-based polyamide prepolymer; the decanediamine and the sebacic acid are derived from castor oil;

[0047] (2) mixing the bio-based polyamide prepolymer, a bio-based polytrimethylene ether glycol, water and a titanium-based catalyst to perform a block polymerization, to obtain a copolymer with a block structure of soft-hard segment alternately arranged;

[0048] (3) mixing the copolymer and nanocellulose, and then performing extrusion and spinning in sequence, and then performing drawing and heat setting in sequence on the obtained as-spun fiber, to obtain the bio-based polyamide elastomer fiber.

[0049] The present application performs polycondensation on decanediamine and sebacic acid to obtain a bio-based polyamide prepolymer.

[0050] Structure of decanediamine

[0051] Structure of sebacic acid:

[0052] The present application mixes decanediamine, sebacic acid, water and a polycondensation catalyst to perform a polycondensation reaction, to obtain a bio-based polyamide prepolymer.

[0053] As an embodiment of the present application, the polycondensation catalyst comprises sodium hypophosphite and / or sodium hypophosphorous acid. Specifically, the polycondensation reaction is preferably a process of mixing decanediamine, sebacic acid, water and a polycondensation catalyst, and then performing salification and polymerization.

[0054] As an embodiment of the present application, the sebacic acid and decamethylenediamine are derived from castor oil. As an embodiment of the present application, the molar ratio of the sebacic acid and decamethylenediamine can be 0.7-0.95:1.0, specifically 0.71:1, 0.85:1, 0.89:1, 0.92:1 and 0.94:1; the mass of the water can be 10% of the mass sum of the sebacic acid and decamethylenediamine; the mass of the polycondensation catalyst can be 0.15% of the mass sum of the sebacic acid, decamethylenediamine and water.

[0055] As an embodiment of the present application, the salting temperature can be 100℃ and the pressure can be 0.2MPa; before the salting reaction, pre-activation is further included; the pre-activation is preferably carried out under the condition of nitrogen and stirring; the heating rate for heating to the pre-activation temperature can be 5℃ / min; the stirring speed can be 50rpm.

[0056] As an embodiment of the present application, the polymerization includes first polymerization, second polymerization, third polymerization and fourth polymerization in sequence.

[0057] As an embodiment of the present application, the temperature of the first polymerization can be 180℃, the pressure can be 0.9-1.1MPa, specifically 1.0MPa, and the time can be 1.0h. As an embodiment of the present application, the temperature of the second polymerization can be 220-240℃, specifically 220℃, 230℃ or 240℃, the pressure can be 1.6-1.8MPa, specifically 1.6MPa, 1.7MPa or 1.8MPa, and the time can be 1.0-1.2h, specifically 1.0h, 1.1h or 1.2h; as an embodiment of the present application, the temperature of the third polymerization can be 220-240℃, specifically 220℃, 230℃ or 240℃, the pressure can be atmospheric pressure, and the time can be 1.0-1.2h, specifically 1h, 1.1h or 1.2h; as an embodiment of the present application, the fourth polymerization is carried out under vacuum, the vacuum pressure is -80kPa, the temperature of the fourth polymerization can be 220-240℃, specifically 220℃, 230℃ or 240℃, and the time can be 0.5-0.6h, specifically 0.5h or 0.6h.

[0058] After obtaining the bio-based polyamide prepolymer, the bio-based polyamide prepolymer, bio-based polytrimethylene ether glycol, water and titanium catalyst are mixed to carry out block polymerization to obtain a copolymer with a block structure of soft-hard segment alternately arranged.

[0059] As an embodiment of the present application, the bio-based polytrimethylene ether glycol has the following structural formula:

[0060]

[0061] As an embodiment of the present application, the molecular weight of the bio-based polytrimethylene glycol ether can be 2000 g / mol; as an embodiment of the present application, the bio-based polytrimethylene glycol ether is preferably obtained by polymerization of 1,3-propanediol fermented from corn sugar.

[0062] As an embodiment of the present application, the mass ratio of the bio-based polyamide prepolymer and the bio-based polytrimethylene ether glycol can be 0.1-1.0:1.0, and specifically can be 0.43:1; the water can be deionized water; the mass of the water can be 15% of the mass of the bio-based polyamide prepolymer and the bio-based polytrimethylene ether glycol.

[0063] As an embodiment of the present application, the titanium-based catalyst can be tetrabutyl titanate; the amount of the titanium-based catalyst can be 0.25% of the total mass of the bio-based polyamide prepolymer, the bio-based polytrimethylene ether glycol, and the water.

[0064] As an embodiment of the present application, the block polymerization is preferably mixing the bio-based polyamide prepolymer, the bio-based polytrimethylene ether glycol, the water, and the polymerization catalyst, and sequentially performing preliminary block polymerization and final block polymerization;

[0065] As an embodiment of the present application, the temperature of the preliminary block polymerization can be 210-230℃, and specifically can be 210℃, 220℃, or 230℃; the pressure can be 0.1-0.3 MPa, and specifically can be 0.25 MPa; the time can be 1.5-3.0 h; the temperature of the final block polymerization can be 240-250℃, and specifically can be 240℃, 245℃, or 250℃; the final block polymerization is performed under vacuum conditions.

[0066] After obtaining the copolymer, the present application mixes the copolymer and nanocellulose, and then sequentially performs extrusion and spinning, and the obtained nascent fiber is sequentially drawn and heat set to obtain the bio-based polyamide elastomer fiber.

[0067] The present application introduces nanocellulose (CNC) as a crosslinking agent to construct a dynamic reversible crosslinking network, increase the hydrogen bond density and the degree of dynamic crosslinking, and improve the mechanical properties and structural stability of the material.

[0068] In the present application, the extrusion and spinning are preferably performed under antioxidant conditions; specifically, the copolymer and nanocellulose and an antioxidant are mixed in the present application before extrusion. The antioxidant is preferably antioxidant 1098. In the present application, the mass of the antioxidant is preferably 1% of the mass of the copolymer and nanocellulose.

[0069] In this invention, the spinning temperature can be 230-250°C. Specifically, in this invention, the spinning temperature can be adjusted according to the melting point of the elastomer; the higher the melting point, the higher the spinning temperature.

[0070] This invention establishes a stable spinning processing window through a dynamic low-temperature extrusion process. Based on the melt flow characteristics of the elastomer resin, the extrusion region is divided into a pre-melt transport zone, a dynamic crosslinking reaction zone, a microphase homogenization zone, and a steady-state rheological control zone. In one embodiment, the pre-melt transport zone is used to premix and transport the block copolyamide, establishing basic rheological properties; its temperature can be 180–200°C. The dynamic crosslinking reaction zone is used for in-situ construction of hydrogen bond networks and shear-induced nanoscale dispersion of soft and hard segments; its temperature can be 200–210°C. The microphase homogenization zone is used to achieve microphase structure homogenization through temperature and pressure gradient control; its temperature can be 210–230°C. The steady-state rheological control zone is used for precise steady-state control of the melt rheological behavior; its temperature can be 230–250°C.

[0071] In this invention, the gradient extrusion and spinning can reduce structural defects in nascent fibers and facilitate industrial production.

[0072] In one embodiment of the present invention, the drawing includes a first-stage drawing and a second-stage drawing performed sequentially; the temperature of the first-stage drawing can be 80-100°C, specifically 80°C, 90°C, or 100°C; the draw ratio of the first-stage drawing can be 2.8-3.2 times, specifically 3.0 times; the temperature of the second-stage drawing can be 160-180°C, specifically 160°C; the draw ratio of the second-stage drawing can be 1.2-1.5 times, specifically 1.2 times, 1.3 times, 1.4 times, or 1.5 times; the heat setting temperature can be 180-200°C, specifically 190°C.

[0073] The present invention also provides the application of the bio-based polyamide elastomer fiber described in the above technical solution, or the bio-based polyamide elastomer fiber described in the above technical solution, in biomedicine, smart sensing, or sportswear.

[0074] As one embodiment of the present invention, the bio-based polyamide elastomer fiber has a service temperature range of -70 to 210°C. When used at the above temperature, the bio-based polyamide elastomer fiber provided by the present invention has good stability.

[0075] To further illustrate the present invention, the following detailed description of the invention's solutions, in conjunction with the accompanying drawings and embodiments, is provided, but should not be construed as limiting the scope of protection of the present invention.

[0076] Example 1

[0077] (1) Weigh 3.36 mol sebacilic acid and 3.01 mol decanediamine, add 10 wt% deionized water (based on the mass of sebacilic acid and decanediamine) and 0.15 wt% sodium hypophosphite (based on the mass of sebacilic acid, decanediamine, and deionized water). Add all the above raw materials to the polymerization reactor, heat at a rate of 5 °C / min under nitrogen pressure of 0.2 MPa, start stirring at 100 °C, control the stirring rate at 50 rpm, and stir for 0.5 h to promote the salt formation of diacid and diamine monomers in the solution.

[0078] In the second stage, the temperature was increased to 180℃ at a rate of 5℃ / min, and the pressure was increased to 1.0MPa. Appropriate venting was used to maintain stable pressure. This temperature and pressure were maintained for 1 hour, then the temperature was increased again to 240℃, and the pressure was adjusted to 1.7MPa. This pressure was maintained for 1 hour, then the pressure was released to atmospheric pressure, and the reaction continued for 1 hour. The reaction was then carried out under vacuum (vacuum pressure -80kPa) for 0.5 hours. When the output water reached 95wt% of the theoretical mass of water (added water + reaction product), the discharge valve was opened for flash evaporation. After pulverizing and drying, the bio-based polyamide prepolymer (denoted as Pre-PA1010, its infrared spectrum is shown below) was obtained. Figure 1 ).

[0079] (2) Weigh 300g of Pre-PA1010 and 700g of PO3G, add 15% deionized water (based on the mass of Pre-PA1010 and PO3G) and 0.25% tetrabutyl titanate (based on the mass of Pre-PA1010, PO3G, and deionized water). Add the mixture to the polymerization reactor, purge the air from the reactor, fill it with 0.25MPa N2, raise the temperature to 210℃, and continue polymerization for 2 hours. Vacuum the reactor and heat it to 240℃. Allow the mixture to react further under vacuum for 2 hours before discharging to obtain the bio-based polyamide elastomer.

[0080] (3) After drying the bio-based polyamide elastomer, it is mixed with nanocellulose (the mass of nanocellulose is 0.5% of the total mass of nanocellulose and bio-based polyamide elastomer) and antioxidant 1098 (the mass of antioxidant 1098 is 1% of the total mass of nanocellulose and bio-based polyamide elastomer) and then fed into a twin-screw extruder. The pre-melt conveying temperature is set at 190°C; the dynamic crosslinking reaction zone is set at 210°C; the microphase homogenization zone is set at 230°C; the steady-state rheology control zone is set at 240°C; and the spinning temperature is set at 240°C. The melt stream extruded through the spinneret is cooled by the cooling system to obtain nascent fibers.

[0081] (6) The nascent fiber is drawn by the spinneret after passing through the first winding hot roller. The spinneret draw ratio is 30-50 times. The temperature of the first collecting roller is 100℃ and the rotation speed is 500m / min, resulting in undrawn yarn.

[0082] (7) The undrawn yarn is drawn in two stages: the first stage drawing temperature is 80℃ and the drawing ratio is 3.0 times; the second stage drawing temperature is 180℃ and the drawing ratio is 1.5 times; the heat setting temperature is 190℃; the second heat setting temperature is 200℃; and the final winding speed is 2500m / min.

[0083] Example 2

[0084] (1) Weigh 3.30 mol sebacilic acid and 3.09 mol decanediamine, add 10% deionized water (based on the mass of sebacilic acid and decanediamine) and 0.15% sodium hypophosphite (based on the mass of sebacilic acid, decanediamine, and deionized water). Add all the above raw materials to the polymerization reactor, heat at a rate of 5℃ / min under nitrogen pressure of 0.2 MPa, start stirring at 100℃, control the stirring rate at 50 rpm, and stir for 0.5 h to promote the salt formation of diacid and diamine monomers in the solution.

[0085] In the second stage, the temperature was increased to 180℃ at a heating rate of 5℃ / min, and the pressure was increased to 1.0MPa. The pressure was kept stable by venting appropriately. After holding the temperature and pressure at this state for 1 hour, the temperature was increased to 240℃ again, and the pressure was adjusted to 1.7MPa. After holding this state for 1 hour, the pressure was released to atmospheric pressure, and the reaction continued for 1 hour. Then, the reaction was carried out under vacuum (vacuum pressure -80kPa) for 0.5 hours. When the water output reached 95% of the total water added, the discharge valve was opened to flash discharge the material. After crushing and drying, the bio-based polyamide prepolymer (denoted as Pre-PA1010) was obtained.

[0086] (2) Weigh 300g of Pre-PA1010 and 700g of PO3G, add 15% deionized water (based on the mass of Pre-PA1010 and PO3G) and 0.25% tetrabutyl titanate (based on the mass of Pre-PA1010, PO3G, and deionized water). Add this mixture to the polymerization reactor, then purge the air from the reactor and fill it with nitrogen gas at 0.25MPa. Raise the temperature to 210℃ and continue for 2 hours. Vacuum the reactor and heat it to 240℃. Allow the mixture to react further under vacuum for 2 hours before discharging to obtain bio-based polyamide elastomer.

[0087] (3) After drying the bio-based polyamide elastomer, it is mixed with nanocellulose (the mass of nanocellulose is 0.5% of the total mass of nanocellulose and bio-based polyamide elastomer) and antioxidant 1098 (the mass of antioxidant 1098 is 1% of the total mass of nanocellulose and bio-based polyamide elastomer) and then fed into a twin-screw extruder. The pre-melt conveying temperature is set to 200°C; the dynamic crosslinking reaction zone is set to 210°C; the microphase homogenization zone is set to 230°C; the steady-state rheology control zone is set to 240°C; and the spinning temperature is set to 250°C. The melt stream extruded through the spinneret is cooled by the cooling system to obtain nascent fibers.

[0088] (6) The nascent fiber is drawn by the spinneret after passing through the first winding hot roller. The spinneret draw ratio is 30-50 times. The temperature of the first collecting roller is 100℃ and the rotation speed is 500m / min, resulting in undrawn yarn.

[0089] (7) The undrawn yarn is drawn in two stages: the first stage drawing temperature is 80℃ and the drawing ratio is 3.0 times; the second stage drawing temperature is 180℃ and the drawing ratio is 1.5 times; the heat setting temperature is 190℃; the second heat setting temperature is 200℃; and the final winding speed is 2500m / min.

[0090] Example 3

[0091] (1) Weigh 3.36 mol sebacilic acid and 3.01 mol decanediamine, add 10% deionized water (based on the mass of sebacilic acid and decanediamine) and 0.15% sodium hypophosphite (based on the mass of sebacilic acid, decanediamine, and deionized water). Add all the above raw materials to the polymerization reactor, heat at a rate of 5℃ / min under nitrogen pressure of 0.2 MPa, start stirring at 100℃, control the stirring rate at 50 rpm, and stir for 0.5 h to promote the salt formation of diacid and diamine monomers in the solution.

[0092] In the second stage, the temperature was increased to 180℃ at a rate of 5℃ / min, and the pressure was increased to 1.0MPa. The pressure was kept stable by venting appropriately. After holding the temperature and pressure at this state for 1 hour, the temperature was increased to 240℃ again, and the pressure was adjusted to 1.7MPa. After holding this state for 1 hour, the pressure was released to atmospheric pressure, and the reaction continued for 1 hour. Then, the reaction was carried out under vacuum (vacuum pressure -80kPa) for 0.5 hours. When the output water reached 95% of the theoretical mass of water (added water + reaction product), the discharge valve was opened to flash discharge the material. After crushing and drying, the bio-based polyamide prepolymer (denoted as Pre-PA1010) was obtained.

[0093] (2) Weigh 500g of Pre-PA1010 and 500g of PO3G, add 15% deionized water (based on the mass of Pre-PA1010 and PO3G), and 0.25% tetrabutyl titanate (based on the mass of Pre-PA1010, PO3G, and deionized water). Add this mixture to the polymerization reactor, then purge the air from the reactor and fill it with nitrogen gas at 0.25MPa. Raise the temperature to 210℃ and continue for 2 hours. Vacuum the reactor and heat it to 240℃. Allow the mixture to react further under vacuum for 2 hours before discharging to obtain bio-based polyamide elastomer.

[0094] (3) After drying, the bio-based polyamide elastomer is mixed with nanocellulose (the mass of nanocellulose is 0.5% of the sum of the masses of nanocellulose and bio-based polyamide elastomer) and antioxidant 1098 (addition amount: 1 wt%), and then fed into a twin-screw extruder. The extrusion temperature is set as follows: pre-melt conveying 200℃; dynamic crosslinking reaction zone 210℃; microphase homogenization zone 230℃; steady-state rheology control zone 240℃; spinning temperature 250℃. The melt stream extruded through the spinneret is cooled to obtain nascent fibers.

[0095] (6) The nascent fiber is drawn by the spinneret after passing through the first winding hot roller. The spinneret draw ratio is 30-50 times. The temperature of the first collecting roller is 100℃ and the rotation speed is 500m / min, resulting in undrawn yarn.

[0096] (7) The undrawn yarn is drawn in two stages. The first stage drawing temperature is 80℃ and the drawing ratio is 3.0 times. The second stage drawing temperature is 180℃ and the drawing ratio is 1.5 times. The heat setting temperature is 190℃ and the second heat setting temperature is 200℃. The final winding speed is 2500m / min.

[0097] Example 4

[0098] (1) Weigh 3.36 mol sebacilic acid and 3.01 mol decanediamine, add 10% deionized water (based on the mass of sebacilic acid and decanediamine) and 0.15% sodium hypophosphite (based on the mass of sebacilic acid, decanediamine, and deionized water). Add all the above raw materials to the polymerization reactor, heat at a rate of 5℃ / min under nitrogen pressure of 0.2 MPa, start stirring at 100℃, control the stirring rate at 50 rpm, and stir for 0.5 h to promote the salt formation of diacid and diamine monomers in the solution.

[0099] In the second stage, the temperature was increased to 180℃ at a rate of 5℃ / min, and the pressure was increased to 1.0MPa. The pressure was kept stable by venting appropriately. After holding the temperature and pressure at this state for 1 hour, the temperature was increased to 240℃ again, and the pressure was adjusted to 1.7MPa. After holding this state for 1 hour, the pressure was released to atmospheric pressure, and the reaction continued for 1 hour. Then, the reaction was carried out under vacuum (vacuum pressure -80kPa) for 0.5 hours. When the output water reached 95% of the theoretical mass of water (added water + reaction product), the discharge valve was opened to flash discharge the material. After crushing and drying, the bio-based polyamide prepolymer (denoted as Pre-PA1010) was obtained.

[0100] (2) Weigh 300g of bio-based PA1010 prepolymer and 700g of PO3G, add 15% deionized water (based on the mass of Pre-PA1010 and PO3G) and 0.25% tetrabutyl titanate (based on the mass of Pre-PA1010, PO3G, and deionized water). Add this mixture to the polymerization reactor, then purge the air from the reactor and fill it with nitrogen gas at 0.25MPa. Raise the temperature to 210℃ and continue for 2 hours. Vacuum the reactor and heat it to 240℃. Allow the mixture to react further under vacuum for 2 hours before discharging to obtain the bio-based polyamide elastomer.

[0101] (3) After drying the bio-based polyamide elastomer, it is mixed with nanocellulose (the mass of nanocellulose is 0.5% of the total mass of nanocellulose and bio-based polyamide elastomer) and antioxidant 1098 (the mass of antioxidant 1098 is 1% of the total mass of nanocellulose and bio-based polyamide elastomer) and then fed into a twin-screw extruder. The pre-melt conveying temperature is set at 190°C; the dynamic crosslinking reaction zone is set at 210°C; the microphase homogenization zone is set at 230°C; the steady-state rheology control zone is set at 240°C; and the spinning temperature is set at 240°C. The melt stream extruded through the spinneret is cooled by the cooling system to obtain nascent fibers.

[0102] (6) The nascent fiber is drawn by the spinneret after passing through the first winding hot roller. The spinneret draw ratio is 30-50 times. The temperature of the first collecting roller is 100℃ and the rotation speed is 500m / min, resulting in undrawn yarn.

[0103] (7) The undrawn yarn is drawn in two stages. The first stage drawing temperature is 80℃ and the drawing ratio is 3.2 times. The second stage drawing temperature is 180℃ and the drawing ratio is 1.8 times. The heat setting temperature is 190℃ and the second heat setting temperature is 200℃. The final winding speed is 2550m / min.

[0104] Comparative Example 1

[0105] (1) Weigh 3.36 mol sebacilic acid and 3.01 mol decanediamine, add 10% deionized water (based on the mass of sebacilic acid and decanediamine) and 0.15% sodium hypophosphite (based on the mass of sebacilic acid, decanediamine, and deionized water). Add all the above raw materials to the polymerization reactor, heat at a rate of 5℃ / min under nitrogen pressure of 0.2 MPa, start stirring at 100℃, control the stirring rate at 50 rpm, and stir for 0.5 h to promote the salt formation of diacid and diamine monomers in the solution.

[0106] In the second stage, the temperature was increased to 180℃ at a heating rate of 5℃ / min, and the pressure was increased to 1.0MPa. The pressure was kept stable by venting appropriately. After holding the temperature and pressure at this state for 1 hour, the temperature was increased to 240℃ again, and the pressure was adjusted to 1.7MPa. After holding this state for 1 hour, the pressure was released to atmospheric pressure, and the reaction continued for 1 hour. Then, the reaction was carried out under vacuum for 0.5 hours. When the water output reached 95wt% of the total water added, the discharge valve was opened to flash discharge the material. After crushing and drying, the bio-based PA1010 prepolymer was obtained.

[0107] (2) Weigh 300g of bio-based PA1010 prepolymer and 700g of PTMEG, add 15% deionized water (based on the mass of bio-based PA1010 prepolymer and PTMEG) and 0.25% tetrabutyl titanate (based on the mass of bio-based PA1010 prepolymer, PTMEG, and deionized water). Add the mixture to the polymerization reactor, then purge the air from the reactor and fill it with nitrogen gas at 0.25MPa. Raise the temperature to 210℃ and continue for 2 hours. Vacuum the reactor and heat it to 240℃. Allow the mixture to react further under vacuum for 2 hours before discharging and drying.

[0108] (3) After drying the bio-based polyamide elastomer, it is mixed with nanocellulose (the mass of nanocellulose is 0.5% of the total mass of nanocellulose and bio-based polyamide elastomer) and antioxidant 1098 (the mass of antioxidant 1098 is 1% of the total mass of nanocellulose and bio-based polyamide elastomer) and then added to a twin-screw extruder. The spinning temperature is set to 240°C. The melt stream extruded through the spinneret is cooled to obtain nascent fibers.

[0109] (6) The nascent fiber is drawn by the spinneret after passing through the first winding hot roller. The spinneret draw ratio is 30-50 times. The temperature of the first collecting roller is 100℃ and the rotation speed is 500m / min, resulting in undrawn yarn.

[0110] (7) The undrawn yarn is drawn in two stages: the first stage drawing temperature is 80℃ and the drawing ratio is 3.0 times; the second stage drawing temperature is 180℃ and the drawing ratio is 1.5 times; the heat setting temperature is 190℃; the second heat setting temperature is 200℃; and the final winding speed is 2500m / min.

[0111] Comparative Example 2

[0112] (1) Weigh 3.36 mol / s dodecanoic acid and 3.01 mol / s 1,12-dodecanediamine, add 10% deionized water (based on the mass of dodecanoic acid and 1,12-dodecanediamine) and 0.15% sodium hypophosphite (based on the mass of dodecanoic acid, 1,12-dodecanediamine and deionized water). Add all the above raw materials to the polymerization reactor, heat at a rate of 5 °C / min under nitrogen pressure of 0.2 MPa, start stirring at 100 °C, control the stirring rate at 50 rpm, and stir for 0.5 h to promote the salt formation of diacid and diamine monomers in the solution.

[0113] In the second stage, the temperature was increased to 180℃ at a heating rate of 5℃ / min, and the pressure was increased to 1.0MPa. The pressure was kept stable by venting appropriately. After holding the temperature and pressure at this state for 1 hour, the temperature was increased to 240℃ again, and the pressure was adjusted to 1.7MPa. After holding this state for 1 hour, the pressure was released to atmospheric pressure, and the reaction continued for 1 hour. Then, the reaction was carried out under vacuum for 0.5 hours. When the water output reached 95wt% of the total water added, the discharge valve was opened to flash discharge the material. After crushing and drying, the bio-based PA1010 prepolymer was obtained.

[0114] (2) Weigh 300g of bio-based PA1010 prepolymer and 700g of PTMEG, add 15% deionized water (based on the mass of bio-based PA1010 prepolymer and PTMEG) and 0.25% tetrabutyl titanate (based on the mass of bio-based PA1010 prepolymer, PTMEG, and deionized water). Add the mixture to the polymerization reactor, then purge the air from the reactor and fill it with nitrogen gas at 0.25MPa. Raise the temperature to 210℃ and continue for 2 hours. Vacuum the reactor and heat it to 240℃. Allow the mixture to react further under vacuum for 2 hours before discharging and drying.

[0115] (3) After drying the bio-based polyamide elastomer, it is mixed with nanocellulose (the mass of nanocellulose is 0.5% of the total mass of nanocellulose and bio-based polyamide elastomer) and antioxidant 1098 (the mass of antioxidant 1098 is 1% of the total mass of nanocellulose and bio-based polyamide elastomer) and then added to a twin-screw extruder. The spinning temperature is set to 240°C. The melt stream extruded through the spinneret is cooled to obtain nascent fibers.

[0116] (6) The nascent fiber is drawn by the spinneret after passing through the first winding hot roller. The spinneret draw ratio is 30-50 times. The temperature of the first collecting roller is 100℃ and the rotation speed is 500m / min, resulting in undrawn yarn.

[0117] (7) The undrawn yarn is drawn in two stages: the first stage drawing temperature is 80℃ and the drawing ratio is 3.0 times; the second stage drawing temperature is 180℃ and the drawing ratio is 1.5 times; the heat setting temperature is 190℃; the second heat setting temperature is 200℃; and the final winding speed is 2500m / min.

[0118] Table 1 Comparison of performance indicators of Examples 1-4 and Comparative Examples 1-2

[0119] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Elastomer tensile strength (MPa) 38.2 41.5 42.6 38.2 39.7 33.5 Elastomer Tg (°C) -25 -27 -29 -26 -19 -18 Elastomer intrinsic viscosity (dL / g) 1.27 1.30 1.34 1.29 1.20 1.18 Elastomer elastic retention (°) 86.2 87.6 88.4 87.1 80.1 81.5 Fiber breaking strength (cN / dtex) 2.91 3.23 3.47 3.05 3.15 2.40 Fiber breaking elongation (%) 561 513 476 492 439 464 Bio-based content (%) ＞90 ＞90 ＞90 ＞90 ＜30 ＜30

[0120] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A bio-based polyamide elastomer fiber, comprising an elastomer and nanocellulose; the elastomer comprising alternating hard segment polymers and soft segment polymers; the hard segment polymer being a bio-based polyamide prepolymer; the soft segment polymer being a bio-based polytrimethylene ether glycol; and the elastomer and nanocellulose being dynamically cross-linked; The hard segment polymer has the structure shown in Formula I; The number-average molecular weight of the hard segment polymer is 1000–5000 g / mol; The mass percentage of the hard segment polymer in the elastomer is 10% to 50%.

2. The bio-based polyamide elastomer fiber as described in claim 1, characterized in that, The elastomer contains 50% to 90% by mass of the soft segment polymer; the number-average molecular weight of the soft segment polymer is 2000 g / mol.

3. The bio-based polyamide elastomer fiber as described in claim 1, characterized in that, The bio-based polyamide elastomer fiber contains ≥90% elastomer by mass; the number-average molecular weight of the elastomer is 20,000 to 30,000 g / mol.

4. A method for preparing the bio-based polyamide elastomer fiber according to any one of claims 1 to 3, comprising the following steps: (1) Decadiamine, sebacic acid, water and polycondensation catalyst are mixed and polycondensation reaction is carried out to obtain bio-based polyamide prepolymer; the decanediamine and sebacic acid are derived from castor oil; (2) Bio-based polyamide prepolymer, bio-based polytrimethylene ether glycol, water and titanium catalyst are mixed and block polymerized to obtain a copolymer with a block structure in which soft and hard segments are arranged alternately. (3) The copolymer and nanocellulose are mixed and then extruded and spun in sequence. The resulting nascent fibers are then stretched and heat-set in sequence to obtain the bio-based polyamide elastomer fiber.

5. The preparation method according to claim 4, characterized in that, The polycondensation reaction is carried out under polycondensation catalyst conditions, wherein the polycondensation catalyst includes sodium hypophosphite and / or sodium hypophosphite. The molar ratio of decanediamine to sebacic acid is 0.7–0.95:1.

0.

6. The preparation method according to claim 4, characterized in that, The extrusion area is divided into a pre-melting transport zone, a dynamic cross-linking reaction zone, a microphase homogenization zone, and a steady-state rheology control zone; the temperature of the pre-melting transport zone is 180–200°C; the temperature of the dynamic cross-linking reaction zone is 200–210°C; the temperature of the microphase homogenization zone is 210–230°C; and the temperature of the steady-state rheology control zone is 230–250°C. The spinning temperature is 230–250°C.

7. The preparation method according to claim 4, characterized in that, The drawing process includes a first-stage drawing and a second-stage drawing performed sequentially; the temperature of the first-stage drawing is 80–100°C, and the drawing ratio of the first-stage drawing is 2.8–3.2 times; the temperature of the second-stage drawing is 160–180°C, and the drawing ratio of the second-stage drawing is 1.2–1.5 times.

8. The preparation method according to claim 4, characterized in that, The heat setting temperature is 180–200°C.

9. The preparation method according to claim 4, characterized in that, The block aggregation is performed by sequentially performing preliminary block aggregation and final block aggregation; The initial block polymerization was carried out at a temperature of 210–230°C, a pressure of 0.1–0.3 MPa, and a time of 1.5–3.0 h. The final block polymerization is carried out under vacuum conditions, at a temperature of 240–250°C, for a time of 1.5–3.0 h.

10. The application of the bio-based polyamide elastomer fiber according to any one of claims 1 to 3 or the bio-based polyamide elastomer fiber prepared by the preparation method according to any one of claims 4 to 9 in biomedicine, smart sensing or sportswear.

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