Hemp tree powder bio-based degradable material and preparation method thereof

Abstract

The hemp tree is a malviaceae hibiscus deciduous tree, the trunk and branches contain 65%-75% of cellulose, the hemp tree grows fast, the adaptability is high, the resource utilization rate is low, and the hemp tree powder can achieve the win-win situation of high value and environmental protection. The invention discloses a hemp tree powder bio-based degradable material and a preparation method thereof. The material is prepared from 42%-58% of hemp tree powder, 28%-38% of polylactic acid (PLA), 4%-7% of nano montmorillonite, 3%-5% of hexamethylene diisocyanate and 1.5%-2.5% of calcium stearate. In the preparation process, the hemp tree powder is subjected to alkaline leaching, acid neutralization and enzymolysis modification, nano-montmorillonite composite modification, polyethylene glycol and PLA graft modification; and carrying out segmented temperature control mixing, optimized feeding, warm water granulation and antioxidant addition to prepare the target material. The oxygen transmission rate of the material is smaller than or equal to 45 cm / (m24h 0.1 MPa), the bending strength is larger than or equal to 26 MPa, the tensile strength retention rate after thermal oxidative aging at 120 DEG C for 168 h is larger than or equal to 88%, and the material is excellent in performance and can be used for packaging and disposable products and efficiently utilizing hemp tree resources.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bio-based composite materials, in particular to a jute tree powder bio-based degradable material and a preparation method thereof. BACKGROUND

[0002] Jute tree, as a deciduous tree of Malvaceae, has the advantages of short growth cycle (1-2 years to be ready for use), strong adaptability (drought and poor soil tolerance, and can be planted on marginal land), and high cellulose content (cellulose content in trunk and branches is 65%-75%). It is a potential renewable plant resource. However, the current jute tree resources are mostly used for low-end board processing or directly burned, and the resource utilization rate is less than 30%. The high-value utilization way is scarce, which causes a large amount of biomass resources to be wasted, and the environmental protection and economic value of jute tree resources cannot be fully utilized.

[0003] The existing technology has multiple bottlenecks: on the one hand, the cellulose content of conventional plant fibers (such as straw powder and wood powder) is lower than that of jute tree powder, and the impurity (lignin and pectin) content is high, which leads to poor compatibility with PLA, low mechanical strength of the composite material, and easy cracking; on the other hand, even if high cellulose plant fibers are used, the existing modification process is mostly single alkali treatment or single coupling agent modification, which cannot effectively optimize the fiber microstructure and interface bonding force, and the modification agent such as nano-montmorillonite is prone to agglomeration, which has limited improvement in barrier property. The brittleness and poor thermal stability of PLA have not been properly solved.

[0004] In terms of preparation process, the raw materials are prone to premature softening and caking due to improper temperature control during high-speed mixing, resulting in uneven mixing; the granulation mostly uses normal temperature water cooling or air cooling, and the moisture content of the particles is high (usually more than 0.3%), and the surface is rough, which affects the quality of subsequent processing. In addition, the existing materials generally lack targeted antioxidant systems, have poor heat-oxidative aging resistance, and are difficult to meet the long-term use requirements in the fields of packaging and disposable products.

[0005] Based on the urgent need for high-value utilization of jute tree resources and the technical defects of existing bio-based degradable materials, it is necessary to develop a bio-based degradable material taking jute tree powder as the core raw material, which has multi-dimensional modification and process optimization, and takes into account the mechanical properties, barrier properties, aging resistance and processing stability, to fill the application gap of jute tree resources in the field of high-end bio-based materials. SUMMARY

[0006] The present application provides a jute tree powder bio-based degradable material and a preparation method thereof, which realizes the deficiency of the material in degradation performance, mechanical property, barrier property and aging resistance by raw material treatment, improved treatment process and processing process parameters.

[0007] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is: The application discloses a kind of jatropha powder biobased degradable materials, by following mass percentage raw materials composition: jatropha powder 42%-58%, polylactic acid (PLA) 28%-38%, nano montmorillonite 4%-7%, hexamethylene diisocyanate (chain extender) 3%-5%, calcium stearate (lubricant) 1.5%-2.5%;The NCO content of the hexamethylene diisocyanate is 31.5%-32.5%, and the calcium content of calcium stearate is 6.5%-7.5%;The jatropha powder pretreatment step is: first in mass fraction 3.5%-4.5% sodium hydroxide solution is soaked 2.2h-2.8h, deionized water washes to neutral, then in mass fraction 2.5%-3.5% hydrochloric acid solution is soaked 1.2h-1.8h, subsequently 70°C-75°C vacuum drying 3h-4h, finally crushes to 180 mesh-230 mesh.

[0008] Further, the nano montmorillonite modification step is: the nano montmorillonite is added to mass fraction 5%-8% cetyltrimethylammonium bromide and mass fraction 1%-2% gamma-aminopropyl triethoxysilane mixed solution, and is stirred and reacted under the condition of 80°C-85°C and rotation speed 300r / min-400r / min for 4h-5h;After reaction, centrifugal separation is carried out, the precipitate is washed with deionized water 3-4 times, and is dried at 90°C-95°C for 6h-7h;After modification, the interlayer spacing of the nano montmorillonite is 4.0nm-5.0nm, the oxygen permeability of the material is not higher than 45cm³ / (m²•24h•0.1MPa), and the heat distortion temperature is not lower than 58°C.

[0009] Further, the PLA modification step is: PLA, mass fraction 2%-3% maleic anhydride and mass fraction 0.1%-0.2% dicumyl peroxide are added to a double-screw extruder, and are melt-grafted under the condition of rotation speed 200r / min-250r / min and temperature 170°C-190°C for 5min-7min;After grafting, PLA appears carboxyl characteristic absorption peak at 1720cm -1 -1730cm -1 , and the grafting rate is 0.8%-1.2%;The weight average molecular weight of the grafted PLA is 195,000-215,000 determined by gel permeation chromatography, and the crystallinity is 33%-37% determined by differential scanning calorimetry.

[0010] Further, the jute powder needs to be additionally subjected to enzymatic hydrolysis treatment: after hydrochloric acid soaking and purification, 0.5%-1% of a cellulase solution by mass fraction is added, and enzymatic hydrolysis is performed at a pH value of 4.5-5.5 and a temperature of 45°C-55°C for 1h-1.5h; after enzymatic hydrolysis, vacuum drying is performed at 70°C-75°C for 2h-3h, and the powder is crushed to 180 mesh-230 mesh; after scanning electron microscope observation, the surface porosity of the jute powder after enzymatic hydrolysis is increased by 30%-40%, the specific surface area is 1.2m² / g-1.5m² / g, the bending strength of the material is not less than 26MPa, and the elongation at break is not less than 8.5%.

[0011] Further, when the nano-montmorillonite is modified, 0.3%-0.5% of polyethylene glycol with a molecular weight of 4000-6000 by mass fraction is added to the mixed solution; after transmission electron microscope observation, the particle size of the agglomerates of the modified nano-montmorillonite in the PLA matrix is less than 50nm, and the uniformity of dispersion is increased by 25%-30%; the impact strength of the material is not less than 5.5kJ / m², and the water vapor transmission rate is not higher than 35g / (m²•24h).

[0012] A preparation method of a jute powder biobased degradable material, comprising the following steps: S1. Raw material mixing: jute powder, modified PLA, modified nano-montmorillonite, hexamethylene diisocyanate, and calcium stearate are added to a high-speed mixer in proportion; the mixing time is controlled by a time relay, with an accuracy of ±0.1s, and the mixing is performed at a rotation speed of 1100r / min-1400r / min for 16min-19min; S2. Melt extrusion molding: the premixed material is added to a co-rotating twin-screw extruder (screw length-diameter ratio 45:1), and the temperature from the feeding section to the die head is set as 165°C, 175°C, 185°C, 195°C, and 200°C in sequence, and the screw rotation speed is 310r / min-340r / min; the extrudate is cooled by a wind cooling draw bar at a wind temperature of 22°C-24°C and a wind speed of 2.3m / s-2.8m / s, and then pelletized to obtain uniform particles.

[0013] Further, the high-speed mixer in S1 is subjected to segmented temperature control: the initial stage is mixed at 40°C-45°C for 8min-10min, and the subsequent stage is mixed at 50°C-55°C for 8min-9min; in this way, the raw materials are prevented from softening and caking in advance, and the uniformity of the premixed material is increased by 15%-20%.

[0014] Further, in the step S2, 0.4%-0.7% of antioxidant is added to the melting section of the twin-screw extruder during melt extrusion, the antioxidant is a mixture of hindered phenol 1010 and phosphite 168 in a mass ratio of 1:1; the antioxidant is mixed with the premix at 165-175 DEG C for 1.5-2.5 min; after 120 DEG C, 168 h thermal-oxidative aging test, the material tensile strength retention rate is not less than 88%, and the notched impact strength retention rate is not less than 83%.

[0015] Further, the feeding sequence of the step S1 is: first, add the modified jute powder and the modified nano montmorillonite, mix for 3-4 min; then add the modified PLA and the antioxidant, mix for 5-6 min; finally, add the hexamethylene diisocyanate and the calcium stearate, mix for 8-9 min; this sequence makes the number average molecular weight of the material reach 180-200 thousand, and the mechanical property stability is improved by 18%-22%.

[0016] Further, in the step S2, warm water cutting is adopted: the cutting water temperature is 32-34 DEG C, and the cutting knife rotating speed is 850-950 r / min; after cutting, the particles are dried by hot air at 40-45 DEG C for 1-1.5 h, and then the particles with a particle size of 2.2-2.8 mm are screened out by a vibrating screen; the water content of the dried particles is 0.1%-0.2%, and the surface smoothness is improved by 10%-15%.

[0017] Advantages of the application On the raw material processing level, by pretreating and enzymatic modifying the jute powder, the surface impurities are effectively removed and the microstructure is optimized, which greatly improves the compatibility of the jute powder with polylactic acid (PLA) and avoids the damage of the material performance caused by insufficient compatibility; the nano montmorillonite is modified and auxiliary modified components are introduced, which significantly improves the dispersibility and reduces the agglomeration, laying a foundation for the improvement of the material performance; the PLA is grafted and modified, which further enhances the interfacial bonding force with the jute powder and cooperates with the chain extender to comprehensively optimize the mechanical properties of the material. On the core performance of the material, after the above modification, the material has excellent mechanical strength and barrier properties, which can meet the use requirements in many fields such as packaging and disposable products; at the same time, through the application of the antioxidant composite system, the thermal-oxidative aging resistance of the material is greatly improved, the service life is prolonged, and the performance stability in long-term use is ensured. In the preparation process, the design of segmented temperature control and optimized feeding sequence of the high-speed mixer effectively avoids the premature softening and caking or early reaction of the raw materials, and improves the dispersion uniformity of the premix; the combination of warm water cutting and hot air drying ensures the stable quality of the final particle product and reduces the subsequent processing defects. Overall, the material realizes the whole life cycle biodegradation and meets the environmental protection requirements, and at the same time, the practical performance and process stability are considered, which has high popularization and application value. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application are described clearly and completely. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0019] Embodiment 1 Raw material ratio (mass percent): joss powder 45%, modified PLA 35%, modified nano-montmorillonite 6%, hexamethylene diisocyanate (NCO content 32%) 4%, calcium stearate (calcium content 7%) 2%.

[0020] Raw material modification: Joss powder: soaked in 3.8% sodium hydroxide solution for 2.5 h → washed to neutral → soaked in 2.8% hydrochloric acid solution for 1.5 h → vacuum dried at 72°C for 3.5 h → pulverized to 200 mesh, then enzymatically hydrolyzed with 0.8% cellulase solution (pH 5.0, 50°C) for 1.2 h → dried and pulverized to 200 mesh.

[0021] Nano-montmorillonite: add 6% cetyltrimethylammonium bromide and 1.5% γ-aminopropyltriethoxysilane mixed solution, stir at 82°C and 350 r / min for 4.5 h → centrifuge → wash with water 4 times → dry at 92°C for 6.5 h, while adding 0.4% polyethylene glycol with a molecular weight of 5000, the modified interlayer spacing is 4.5 nm.

[0022] PLA: mixed with 2.5% maleic anhydride and 0.15% dicumyl peroxide, extruded by double screw at 220 r / min and 180°C for 7 min, grafting rate 1.0%, weight average molecular weight 200,000, crystallinity 35%.

[0023] Preparation process: S1: feed according to "modified joss powder + modified nano-montmorillonite (mixed for 3.5 min) → modified PLA + antioxidant (1010 and 168 mixed at 1:1, 0.5%) (mixed for 5.5 min) → hexamethylene diisocyanate + calcium stearate (mixed for 8.5 min)", mix at 42°C for 9 min → heat to 52°C and mix for 8.5 min, total mixing time 18 min at 1200 r / min.

[0024] S2: add the premixed material into a double screw extruder with a length-diameter ratio of 45:1, temperature 165°C → 175°C → 185°C → 195°C → 200°C, 320 r / min; the extrudate is air-cooled by a 23°C, 2.5 m / s air flow, cut into particles in 33°C warm water (900 r / min), hot air dried at 42°C for 1.2 h, and screened for 2.5 mm particles.

[0025] Product performance: oxygen permeability 42 cm3 / (m2·24h·0.1 MPa), heat distortion temperature 60℃, bending strength 27 MPa, elongation at break 9%, impact strength 5.8 kJ / m2, water vapor permeability 33 g / (m2·24h); after 120℃, 168h thermal-oxidative aging, tensile strength retention rate 90%, notched impact strength retention rate 85%, particle moisture content 0.15%.

[0026] Example 2 Raw material ratio (mass percent): jatropha powder 50%, modified PLA 30%, modified nano-montmorillonite 5%, hexamethylene diisocyanate (NCO content 31.5%) 5%, calcium stearate (calcium content 6.5%) 1.5%.

[0027] Raw material modification: Jatropha powder: 4.2% sodium hydroxide solution immersion 2.3h→water washing neutral→3.2% hydrochloric acid solution immersion 1.3h→74℃ vacuum drying 3.2h→pulverization to 220 mesh, 0.6% cellulase solution (pH 4.8, 48℃) enzymolysis 1.3h→dry pulverization to 220 mesh.

[0028] Nano-montmorillonite: 7% hexadecyl trimethyl ammonium bromide and 1.2% γ-aminopropyl triethoxysilane mixed solution, 83℃, 320r / min stirring reaction 4.2h→centrifugation→water washing 3 times→94℃ drying 6.2h, 0.35% polyethylene glycol with molecular weight 4500 is added, and the interlayer spacing of the modified product is 4.2nm.

[0029] PLA: mixed with 2.2% maleic anhydride and 0.12% dicumyl peroxide, 210r / min, 175℃ double screw extrusion grafting 6min, grafting rate 0.9%, weight average molecular weight 198,000, crystallinity 34%.

[0030] Preparation process: S1: according to "modified jatropha powder+modified nano-montmorillonite (mixed for 3.2min)→modified PLA+antioxidant (0.45%) (mixed for 5.2min)→hexamethylene diisocyanate+calcium stearate (mixed for 8.2min)", 41℃ mixing 8.5min→temperature rising to 51℃ mixing 8.2min, total mixing 16.9min at 1150r / min.

[0031] S2: double screw extruder temperature 165℃→175℃→185℃→195℃→200℃, 310r / min; the extrudate is cooled by air at 22℃ and 2.4m / s, cut into particles in 32℃ warm water (880r / min), dried by hot air at 41℃ for 1.1h, and screened for 2.3mm particles.

[0032] Product performance: oxygen permeability 43 cm3 / (m2·24h·0.1MPa), heat distortion temperature 59℃, bending strength 26.5 MPa, elongation at break 8.8%, impact strength 5.6 kJ / m2, water vapor permeability 34 g / (m2·24h); after 120℃, 168h thermal-oxidative aging, tensile strength retention rate 89%, notched impact strength retention rate 84%, particle moisture content 0.13%.

[0033] Example 3 Raw material ratio (mass percent): jatropha curcas powder 55%, modified PLA 28%, modified nano-montmorillonite 7%, hexamethylene diisocyanate (NCO content 32.5%) 3%, calcium stearate (calcium content 7.5%) 2.5%.

[0034] Raw material modification: Jatropha curcas powder: 3.5% sodium hydroxide solution immersion 2.7h→water washing neutral→2.5% hydrochloric acid solution immersion 1.7h→71℃ vacuum drying 3.8h→pulverization to 190 mesh, 0.9% cellulase solution (pH 5.2, 52℃) enzymolysis 1.4h→dry pulverization to 190 mesh.

[0035] Nano-montmorillonite: 5.5% hexadecyl trimethyl ammonium bromide mixed solution with 1.8% γ-aminopropyl triethoxysilane, 81℃, 380r / min stirring reaction 4.8h→centrifugation→water washing 4 times→91℃ drying 6.8h, adding 0.45% polyethylene glycol with molecular weight 5500, after modification, the interlayer 4.8 nm from.

[0036] PLA: mixed with 2.8% maleic anhydride, 0.18% dicumyl peroxide, 240r / min, 185℃, double screw extrusion grafting 5.5min, grafting rate 1.1%, weight average molecular weight 205,000, crystallinity 36%.

[0037] Preparation process: S1: according to "modified jatropha curcas powder+modified nano-montmorillonite (mixed for 3.8min)→modified PLA+antioxidant (0.65%) (mixed for 5.8min)→hexamethylene diisocyanate+calcium stearate (mixed for 8.8min)", 44℃ mixing 9.5min→temperature rising to 54℃ mixing 8.8min, total mixing 18.1min at 1300r / min.

[0038] S2: double screw extruder temperature 165℃→175℃→185℃→195℃→200℃, 340r / min; the extrudate is cooled by air at 24℃, 2.7m / s, cut into particles in 34℃ warm water (950r / min), dried by hot air at 44℃ for 1.4h, and screened for 2.7mm particles.

[0039] Product performance: oxygen permeability 40 cm3 / (m2·24h·0.1 MPa), heat distortion temperature 61℃, bending strength 27.5 MPa, elongation at break 9.2%, impact strength 6.0 kJ / m2, water vapor permeability 32 g / (m2·24h); after 120℃, 168h thermal oxygen aging, tensile strength retention rate 91%, notched impact strength retention rate 86%, particle moisture content 0.17%.

[0040] Comparative Example 1 (raw materials not modified, corresponding to Example 1): Raw material ratio (mass percentage): consistent with Example 1, i.e. 45% of jute powder, 35% of unmodified PLA, 6% of unmodified nano-montmorillonite, 4% of hexamethylene diisocyanate (NCO content 32%), and 2% of calcium stearate (calcium content 7%).

[0041] Raw material treatment: The jute powder was only vacuum dried at 72℃ for 3.5h and crushed to 200 mesh, without alkali leaching-acid neutralization-enzymatic hydrolysis treatment; The nano-montmorillonite was used directly without modification with cetyltrimethylammonium bromide and γ-aminopropyltriethoxysilane, and without the addition of polyethylene glycol; The PLA was used directly without maleic anhydride grafting modification.

[0042] Preparation process: consistent with Example 1 (the process of segmented temperature control mixing, warm water pelletizing, etc. remains unchanged).

[0043] Product performance: oxygen permeability 78 cm3 / (m2·24h·0.1 MPa) (85.7% higher than Example 1), heat distortion temperature 45℃ (25% lower than Example 1), bending strength 18 MPa (33.3% lower than Example 1), elongation at break 5.2% (42.2% lower than Example 1), impact strength 3.1 kJ / m2 (46.6% lower than Example 1), water vapor permeability 68 g / (m2·24h) (106.1% higher than Example 1); after 120℃, 168h thermal oxygen aging, tensile strength retention rate 65% (27.8% lower than Example 1), notched impact strength retention rate 58% (31.8% lower than Example 1), the particles partially clumped due to poor compatibility of the raw materials, moisture content 0.32% (113.3% higher than Example 1).

[0044] Comparative Example 2 (simplified preparation process, corresponding to Example 2): Raw material ratio and modification: consistent with Example 2 (jute powder alkali leaching-acid neutralization-enzymatic hydrolysis, nano-montmorillonite composite modification, and PLA grafting modification remain unchanged).

[0045] Preparation process (key process simplified): S1 step does not use segmented temperature control, the whole process is mixed at 45℃ for 16.9 min, and the feeding sequence is changed to all raw materials are added at one time instead of "jatropha powder + nano montmorillonite → PLA + antioxidant → chain extender + lubricant". S2 step does not use warm water cutting, but uses normal temperature water cooling cutting (water temperature 20℃), and does not perform hot air drying.

[0046] Product performance: oxygen transmission rate 59 cm³ / (m²•24h•0.1MPa) (37.2% higher than example 2), heat distortion temperature 54℃ (8.5% lower than example 2), bending strength 22MPa (17.0% lower than example 2), elongation at break 7.1% (19.3% lower than example 2), impact strength 4.5kJ / m² (19.6% lower than example 2), water vapor transmission rate 45g / (m²•24h) (32.4% higher than example 2); after 120℃, 168h thermal aging, tensile strength retention rate 76% (14.6% lower than example 2), notched impact strength retention rate 72% (14.3% lower than example 2), particle surface rough, particle size uneven (2.0-3.5mm), moisture content 0.25% (92.3% higher than example 2).

[0047] Comparative example 3 (lack of antioxidant, corresponding to example 3): Raw material ratio and modification: consistent with example 3, but S2 step does not add "hindered phenol 1010 + phosphite 168" antioxidant composite system.

[0048] Preparation process: except that no antioxidant is added, the rest of the process (segmented temperature control, optimized feeding sequence, warm water cutting, etc.) is consistent with example 3.

[0049] Product performance: oxygen transmission rate 45 cm³ / (m²•24h•0.1MPa) (12.5% higher than example 3), heat distortion temperature 59℃ (3.3% lower than example 3), bending strength 26MPa (5.5% lower than example 3), elongation at break 8.7% (5.4% lower than example 3), impact strength 5.4kJ / m² (10% lower than example 3), water vapor transmission rate 36g / (m²•24h) (12.5% higher than example 3); anti-aging performance decreased significantly: after 120℃, 168h thermal aging, tensile strength retention rate 58% (36.3% lower than example 3), notched impact strength retention rate 49% (43.0% lower than example 3), material surface appears obvious yellowing and embrittlement, particle moisture content 0.18% (close to example 3, because the drying process is unchanged).

[0050] The test results of 3 examples and 3 comparative examples are shown in the table: Table 1 test results table From the table of test results, it can be seen that Examples 1-3 adopt "raw material modification (alkali leaching of jute powder-acid neutralization-enzymatic hydrolysis, nano-montmorillonite composite modification, PLA graft modification) + process optimization (segmented temperature control mixing, optimized feeding sequence, warm water pelleting, antioxidant addition)", verifying the feasibility and superiority of the technical scheme; Comparative Examples 1-3 respectively through "canceling raw material modification" "simplifying the preparation process" "missing antioxidant", targeted comparison of the influence of single variable on material performance, highlighting the necessity of the key technology of the application.

[0051] Core differences and conclusions: Comparative Example 1 (raw material not modified) vs. Example 1: Poor compatibility of unmodified raw material, material mechanical properties, barrier properties, and anti-aging properties all decreased significantly (such as a 33.3% decrease in bending strength and an 85.7% increase in oxygen transmission rate), proving that raw material modification is the core of improving the comprehensive performance of the material; Comparative Example 2 (simplified process) vs. Example 2: Non-segmented temperature control, unordered feeding, and cold water pelleting result in uneven mixing and poor particle quality, and the material performance overall declines (such as a 19.3% decrease in elongation at break and a 92.3% increase in particle moisture content), indicating that process optimization is the key to ensuring performance stability; Comparative Example 3 (missing antioxidant) vs. Example 3: No antioxidant makes the anti-aging performance drop sharply (36.3% decrease in tensile strength retention rate), and other properties decrease slightly, proving the importance of the antioxidant composite system to the service life of the material.

[0052] Although embodiments of the application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A jatropha powder bio-based degradable material, characterized in that, The raw materials are composed of the following quality percentages: jute powder 42%-58%, modified polylactic acid 28%-38%, modified nano-montmorillonite 4%-7%, hexamethylene diisocyanate 3%-5%, and calcium stearate 1.5%-2.5%; the NCO content of the hexamethylene diisocyanate is 31.5%-32.5%, and the calcium content of the calcium stearate is 6.5%-7.5%; the jute powder pretreatment step is: first soaked in a 3.5%-4.5% sodium hydroxide solution for 2.2-2.8 hours, washed with deionized water until neutral, then soaked in a 2.5%-3.5% hydrochloric acid solution for 1.2-1.8 hours, followed by vacuum drying at 70-75°C for 3-4 hours, and finally ground to 180-230 mesh.

2. The jathropa bio-based biodegradable material according to claim 1, wherein, The modification step of the modified nano-montmorillonite is: adding the nano-montmorillonite into a mixed solution of 5%-8% cetyltrimethylammonium bromide and 1%-2% γ-aminopropyltriethoxysilane, stirring and reacting at 80-85°C and a rotation speed of 300-400 r / min for 4-5 hours; after the reaction, centrifugal separation is performed, the precipitate is washed with deionized water for 3-4 times, and dried at 90-95°C for 6-7 hours.

3. The jatropha-based biodegradable material according to claim 1, wherein, The modification step of the modified polylactic acid is: adding PLA, 2%-3% maleic anhydride, and 0.1%-0.2% dicumyl peroxide into a twin-screw extruder, melt grafting at a rotation speed of 200-250 r / min and a temperature of 170-190°C for 5-7 minutes.

4. The jathropa bio-based biodegradable material of claim 1, wherein, The jute powder needs to be additionally subjected to enzymatic hydrolysis treatment: after hydrochloric acid soaking and purification, 0.5%-1% cellulase solution is added, and enzymatic hydrolysis is performed at a pH of 4.5-5.5 and a temperature of 45-55°C for 1-1.5 hours; after the enzymatic hydrolysis, vacuum drying is performed at 70-75°C for 2-3 hours, and the powder is ground to 180-230 mesh.

5. The jathropa bio-based biodegradable material according to claim 2, wherein, When the nano-montmorillonite is modified, 0.3%-0.5% polyethylene glycol with a molecular weight of 4000-6000 is added to the mixed solution.

6. A method for producing a jatropha powder biobased degradable material, for producing the jatropha powder biobased degradable material according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1. Raw material mixing: jute powder, modified PLA, modified nano-montmorillonite, hexamethylene diisocyanate, and calcium stearate are added into a high-speed mixer in proportion; the mixing time is controlled by a time relay, and the precision is ±0.1 s; the mixing is performed at a rotation speed of 1100-1400 r / min for 16-19 minutes; S2. Melt extrusion molding: the premixed material is added into a co-rotating twin-screw extruder, and the temperature of the feeding section to the die head is set to 165°C, 175°C, 185°C, 195°C, and 200°C in sequence; the screw rotation speed is 310-340 r / min; the extrudate is cooled by a wind tunnel with a wind temperature of 22-24°C and a wind speed of 2.3-2.8 m / s, and then pelletized to obtain uniform particles.

7. The production method according to claim 6, wherein The high-speed mixer in S1 step is controlled in sections: 40-45 DEG C in the initial stage for 8-10 min, and 50-55 DEG C in the subsequent stage for 8-9 min.

8. The preparation method according to claim 6, characterized in that In S2 step, 0.4-0.7% of antioxidant by mass is added to the melting section of the twin-screw extruder, the antioxidant is a mixture of hindered phenol 1010 and phosphite 168 at a mass ratio of 1:1, and the antioxidant and the premix are mixed at 165-175 DEG C for 1.5-2.5 min.

9. The preparation method according to claim 6, characterized in that The feeding sequence in S1 step is: first, add the modified jute powder and the modified nano montmorillonite, mix for 3-4 min; then, add the modified PLA and the antioxidant, mix for 5-6 min; finally, add the hexamethylene diisocyanate and the calcium stearate, mix for 8-9 min.

10. The method of claim 6, wherein, In S2 step, warm water is used for pelletizing: the water temperature is 32-34 DEG C, and the cutter rotation speed is 850-950 r / min; after pelletizing, the particles are dried by hot air at 40-45 DEG C for 1-1.5 h, and then the particles with a particle size of 2.2-2.8 mm are screened out by a vibrating screen.

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