Modified palm fiber, and preparation method and application thereof

Abstract

This invention discloses a modified palm fiber, its preparation method, and its application. The preparation method includes: subjecting palm fiber to alkali washing to obtain alkali-treated palm fiber; wherein the alkali-treated palm fiber has a porous internal structure; subjecting a mixed reaction system containing the alkali-treated palm fiber, methanol, and a catalyst to an esterification reaction to obtain esterified palm fiber; and reacting the esterified palm fiber with a carbon-based conductive agent and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide to obtain modified palm fiber. The modified palm fiber prepared by this invention exhibits excellent antistatic properties, and the carbon-based and non-carbon-based conductive agents bond well with the fiber. It can be woven or used in plant fiber-filled composite materials, and the surface resistivity of the palm fiber can preferably reach 10 Ω·cm. 8 With a strength of Ω*cm, it reaches the antistatic level, expanding the application scenarios of palm fiber.

Description

Technical Field

[0001] This invention belongs to the field of biomass processing and modification technology, specifically relating to a modified palm fiber, its preparation method, and its application. Background Technology

[0002] Biomass resources have garnered significant attention in today's environmentally conscious world due to their eco-friendly and recyclable nature. Plants can convert carbon dioxide into cellulose, lignin, hemicellulose, and various nutrients through photosynthesis. Humans have used wood as building material, leaves for clothing, and vines for tools for thousands of years.

[0003] Palm oil, a widely grown economic crop in southern my country and Southeast Asia, has a huge yield. Its main function is to provide humans with palm oil and palm fiber as raw materials for daily life. The entire palm plant is rich in palmitic acid, also known as hexadecanoic acid, a saturated higher fatty acid. The palmitic acid content can reach more than 8% in the palm bagasse after oil extraction and the fibers of other parts of the palm. However, the palm bagasse after oil extraction and the remaining parts after the high-quality palm fiber are stripped cannot be effectively utilized.

[0004] Currently, some technologies have been developed that incorporate palm fiber as a filler into composite materials to enhance material performance and reduce costs. For example, patent CN102674791A incorporates palm fiber into boards, and patent CN110509630A combines palm fiber with polylactic acid to form nonwoven fabric for mats. However, there are no reports on how to utilize the palmitic acid-rich property of palm fiber to functionalize and modify it, giving it new value and performance. Summary of the Invention

[0005] The main objective of this invention is to provide a modified palm fiber, its preparation method, and its application, in order to overcome the shortcomings of the prior art.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0007] This invention provides a method for preparing modified palm fiber, comprising:

[0008] Palm fibers are subjected to alkali washing to obtain alkali-treated palm fibers; wherein, the interior of the alkali-treated palm fibers has a porous structure caused by the decomposition of lignin by alkali.

[0009] An esterification reaction is carried out on a mixed reaction system containing the alkali-treated palm fiber, methanol, and a catalyst to obtain esterified palm fiber.

[0010] Furthermore, the esterified palm fiber is mixed and reacted with a carbon-based conductive agent and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide to obtain modified palm fiber.

[0011] This invention also provides modified palm fiber prepared by the aforementioned method, wherein the surface resistivity of the modified palm fiber is 10. 10 Below Ω*cm.

[0012] The present invention also provides the use of the aforementioned modified palm fiber in the preparation of palm-woven household goods or plant fiber-filled composite materials.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: the modified palm fiber prepared by the present invention has excellent antistatic properties, and the carbon-based and non-carbon-based conductive agents are well integrated with the fiber. It can be woven or used in plant fiber filled composite materials, and the surface resistivity of the palm fiber can reach 10 Ω·cm. 8 Ω*cm expands the application scenarios of palm fiber. Detailed Implementation

[0014] In view of the deficiencies of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. It mainly utilizes the lignin and impurities removed from palm fibers to form voids, and utilizes the abundant palmitic acid chemical properties in palm to carry out a methyl esterification reaction. After adding a carbon-based conductive agent and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide, they are uniformly combined in methyl palmitate. After removing methanol and cooling to room temperature, methyl palmitate turns back to solid, tightly binding the conductive agent and giving palm antistatic properties.

[0015] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Specifically, as one aspect of the technical solution of this invention, a method for preparing modified palm fiber includes:

[0017] Palm fibers are subjected to alkali washing to obtain alkali-treated palm fibers; wherein, the interior of the alkali-treated palm fibers has a porous structure caused by the decomposition of lignin by alkali.

[0018] An esterification reaction is carried out on a mixed reaction system containing the alkali-treated palm fiber, methanol, and a catalyst to obtain esterified palm fiber.

[0019] Furthermore, the esterified palm fiber is mixed and reacted with a carbon-based conductive agent and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide to obtain modified palm fiber.

[0020] This invention removes lignin from palm fibers by alkaline washing, creating some loose areas inside. Then, after methyl esterification, carbon-based and non-carbon-based conductive agents are dispersed into the interior and adhere to the exterior of the fiber. After cooling, methyl palmitate becomes solid, which can fix the conductive agent inside and on the surface of the fiber, forming a stable conductive network structure.

[0021] In some preferred embodiments, the preparation method specifically includes: mixing palm fiber with an alkaline solution and stirring at 60-80°C for 2-6 hours, followed by washing with water and drying to obtain the alkaline-treated palm fiber.

[0022] Furthermore, the alkaline solution includes, but is not limited to, sodium hydroxide solution and / or potassium hydroxide solution.

[0023] Furthermore, the concentration of the alkaline solution is 3-7 wt%.

[0024] Furthermore, the water washing treatment ensures that the pH of the resulting product is at least neutral.

[0025] In some preferred embodiments, the alkaline washing treatment is used at least to remove impurities, small molecule pigments and some lignin from the palm fibers, making the interior of the palm fibers loose and forming pores.

[0026] In some preferred embodiments, the preparation method specifically includes: stirring a mixed reaction system containing the alkali-treated palm fiber, methanol and catalyst at 65-70°C for 2-4 hours to obtain a reaction solution containing esterified palm fiber.

[0027] Furthermore, the reaction temperature is 67°C.

[0028] Furthermore, the methanol is both a solvent and a reactant, and a sufficient amount is added.

[0029] Furthermore, the catalyst includes, but is not limited to, a cerium phosphotungstenate catalyst.

[0030] Furthermore, the mass ratio of the catalyst to the alkali-treated palm fiber is 0.5:100-2:100.

[0031] Furthermore, the preparation method specifically includes: adding a carbon-based conductive agent and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide to the reaction solution containing esterified palm fiber and dispersing them by ultrasonication, followed by washing with water and drying to obtain the modified palm fiber.

[0032] Furthermore, the mass ratio of the carbon-based conductive agent to the alkali-treated palm fiber is 3:100-5:100.

[0033] Furthermore, the mass ratio of the tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide to the alkali-treated palm fiber is 1:100-3:100.

[0034] Furthermore, the ultrasonic dispersion uses an ultrasonic frequency of 10-100 kHz and a duration of 0.5-4 hours.

[0035] In some preferred embodiments, the palm fiber includes, but is not limited to, palm plant fiber that has been harvested, dried and then simply sheared and crushed, or the residue from palm oil extraction.

[0036] In some preferred embodiments, the carbon-based conductive agent is a multi-walled carbon nanotube and / or a mixture of multi-walled carbon nanotubes and conductive carbon black.

[0037] Furthermore, the mass ratio of multi-walled carbon nanotubes and / or multi-walled carbon nanotubes to conductive carbon black in the carbon-based conductive agent is 1:1-3:1.

[0038] In some more specific embodiments, the method for preparing the modified palm fiber specifically includes:

[0039] (1) Alkali washing: The palm fiber is heated and stirred in a sodium hydroxide aqueous solution to remove impurities, small molecule pigments and some lignin from the palm fiber, making the inside of the palm fiber loose and forming pores. Then it is washed with water until neutral and dried.

[0040] (2) The palm fiber obtained in step (1) is placed in methanol, cerium phosphotungstic acid catalyst is added, and the mixture is heated and stirred to methylate the palmitate in the palm fiber.

[0041] (3) Add carbon-based conductive agent and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide to the reaction solution, stir thoroughly and then disperse by ultrasonication;

[0042] (4) Cool to room temperature, wash away excess conductive agents and other substances with water, and dry to obtain modified palm fiber.

[0043] Another aspect of the present invention provides modified palm fibers prepared by the aforementioned method, wherein the surface resistivity of the modified palm fibers is 10. 10 Below Ω*cm.

[0044] Another aspect of the present invention provides the use of the aforementioned modified palm fiber in woven or plant fiber-filled composite materials.

[0045] For example, palm fiber is used in everyday items to eliminate static electricity and in plant fiber-filled composite materials to obtain antistatic functional modifications.

[0046] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments. These embodiments are implemented on the premise of the technical solution of the invention, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0047] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0048] Example 1

[0049] Palm fiber was placed in a 3% NaOH aqueous solution and stirred at 60°C for 6 hours. It was then washed with water until neutral and dried. 50g of the alkali-treated palm fiber was taken and excess methanol was added to cover the treated palm fiber. 0.25g of cerium phosphotungstic acid catalyst was added, and the mixture was heated to 65°C and reacted for 2 hours. 1.5g of multi-walled carbon nanotubes and 0.5g of tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide were added, and the mixture was stirred at 10 kHz and ultrasonically dispersed for 4 hours. After removing the methanol, the mixture was cooled to room temperature, washed with water, and dried to obtain modified palm fiber. Its surface resistivity is shown in Table 1.

[0050] Example 2

[0051] Palm fiber was placed in a 7% NaOH aqueous solution and stirred at 80°C for 2 hours. It was then washed with water until neutral and dried. 100g of the alkali-treated palm fiber was taken and excess methanol was added to cover the treated palm fiber. 2g of cerium phosphotungstic acid catalyst was added, and the mixture was heated to 70°C and reacted for 2 hours. 2g of multi-walled carbon nanotubes, 2g of ultrafine conductive carbon black, and 3g of tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide were added. After stirring, the mixture was ultrasonically dispersed at 100 kHz for 0.5 hours. After removing the methanol, the mixture was cooled to room temperature, washed with water, and dried to obtain modified palm fiber. Its surface resistivity is shown in Table 1.

[0052] Example 3

[0053] Palm fiber was placed in a 5% NaOH aqueous solution and stirred at 70°C for 4 hours. It was then washed with water until neutral and dried. 100g of the alkali-treated palm fiber was taken and excess methanol was added to cover the treated palm fiber. 1g of cerium phosphotungstic acid catalyst was added, and the mixture was heated to 67°C and reacted for 3 hours. 2.5g of multi-walled carbon nanotubes, 2.5g of ultrafine conductive carbon black, and 1g of tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide were added. After stirring, the mixture was ultrasonically dispersed at 20 kHz for 2 hours. After removing the methanol, the mixture was cooled to room temperature, washed with water, and dried to obtain modified palm fiber. Its surface resistivity is shown in Table 1.

[0054] Example 4

[0055] Palm fiber was placed in a 6% NaOH aqueous solution and stirred at 75°C for 4 hours. It was then washed with water until neutral and dried. 50g of the alkali-treated palm fiber was taken and excess methanol was poured in to cover the treated palm fiber. 0.75g of cerium phosphotungstic acid catalyst was added, and the temperature was raised to 67°C for 3 hours. 0.9g of multi-walled carbon nanotubes, 0.3g of ultrafine conductive carbon black, and 1g of tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide were added. After stirring, the mixture was ultrasonically dispersed at 50 kHz for 3 hours. After removing the methanol, the mixture was cooled to room temperature, washed with water, and dried to obtain modified palm fiber. Its surface resistivity is shown in Table 1.

[0056] Example 5

[0057] Palm fiber was placed in a 7% NaOH aqueous solution and stirred at 75°C for 4 hours. It was then washed with water until neutral and dried. 50g of the alkali-treated palm fiber was taken and excess methanol was added to cover the treated palm fiber. 0.5g of cerium phosphotungstic acid catalyst was added, and the temperature was raised to 67°C for 4 hours. 1g of multi-walled carbon nanotubes, 0.5g of ultrafine conductive carbon black, and 1.5g of tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide were added. After stirring, the mixture was ultrasonically dispersed at 80 kHz for 4 hours. After removing the methanol, the mixture was cooled to room temperature, washed with water, and dried to obtain modified palm fiber. Its surface resistivity is shown in Table 1.

[0058] Comparative Example 1

[0059] The method is the same as in Example 1, except that the alkaline washing treatment is omitted. The surface resistance is shown in Table 1.

[0060] Comparative Example 2

[0061] The method is the same as in Example 1, except that the esterification treatment is not performed. The surface resistance is shown in Table 1.

[0062] Table 1. Surface resistivity results of modified palm fibers in Examples 1-3.

[0063] name Surface resistivity (Ω*cm) Raw palm fiber <![CDATA[10 15 ]]> Example 1 <![CDATA[10 9 ]]> Example 2 <![CDATA[10 8 ]]> Example 3 <![CDATA[10 9 ]]> Example 4 <![CDATA[10 8 ]]> Example 5 <![CDATA[10 9 ]]> Comparative Example 1 <![CDATA[10 14 ]]> Comparative Example 2 <![CDATA[10 14 ]]>

[0064] The modified palm fibers obtained in Examples 1-3 and Comparative Examples 1-2 were added to polypropylene as fillers using a micro twin-screw extruder and a micro injection molding machine, and their surface resistivity was tested.

[0065] name Surface resistivity (Ω*cm) Pure PP <![CDATA[10 15 ]]> 70% PP + 30% Example 1 <![CDATA[10 11 ]]> 70% PP + 30% Example 2 <![CDATA[10 10 ]]> 70% PP + 30% Example 3 <![CDATA[10 11 ]]> 70% PP + 30% Example 4 <![CDATA[10 11 <!-- 4 -->]]> 70% PP + 30% Example 5 <![CDATA[10 10 ]]> 70% PP + 30% Comparative Example 1 <![CDATA[10 14 ]]> 70% PP + 30% Comparative Example 2 <![CDATA[10 15 ]]>

[0066] As can be seen, the surface resistivity of both the tested fiber and the fiber-filled composite material was greatly improved.

[0067] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0068] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for preparing modified palm fiber, characterized in that... include: Palm fiber is mixed with an alkaline solution and stirred at 60-80℃ for 2-6 hours, followed by washing and drying to obtain alkali-treated palm fiber; wherein, the alkali-treated palm fiber has a porous structure due to the decomposition of lignin by the alkali; the concentration of the alkaline solution is 3-7wt%; the palm fiber is selected from palm plant fiber that has been harvested, dried and then simply sheared and crushed or from the waste residue after palm oil extraction. The mixed reaction system containing the alkali-treated palm fiber, methanol and catalyst is stirred at 65-70°C for 2-4 hours to obtain esterified palm fiber. Furthermore, the esterified palm fiber is mixed and reacted with a carbon-based conductive agent and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide to obtain modified palm fiber; the mass ratio of the carbon-based conductive agent to the alkali-treated palm fiber is 3~5:100; the mass ratio of the tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide to the alkali-treated palm fiber is 1:100~3:100; The surface resistivity of the modified palm fiber is 10. 10 Below Ω*cm.

2. The preparation method according to claim 1, characterized in that: The alkaline solution is selected from sodium hydroxide solution and / or potassium hydroxide solution.

3. The preparation method according to claim 1, characterized in that: The washing process ensures that the pH of the resulting product is at least neutral.

4. The preparation method according to claim 1, characterized in that: The catalyst is selected from cerium phosphotungstate catalysts.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the catalyst to the alkali-treated palm fiber is 0.5:100-2:

100.

6. The preparation method according to claim 1, characterized in that... Specifically, it includes: A carbon-based conductive agent and tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)imide were added to the reaction solution containing esterified palm fiber and dispersed by ultrasonication. The mixture was then washed with water and dried to obtain the modified palm fiber.

7. The preparation method according to claim 6, characterized in that: The ultrasonic dispersion uses an ultrasonic frequency of 10kHz-100kHz and a duration of 0.5-4h.

8. The preparation method according to claim 1, characterized in that: The carbon-based conductive agent is a mixture of multi-walled carbon nanotubes and / or multi-walled carbon nanotubes and conductive carbon black; the mass ratio of multi-walled carbon nanotubes and / or multi-walled carbon nanotubes to conductive carbon black in the carbon-based conductive agent is 1:3-3:

1.

9. Modified palm fiber prepared by any one of claims 1-8.

10. Use of the modified palm fiber according to claim 9 in the preparation of palm-woven household goods or plant fiber-filled composite materials.