High-performance composite material prepared from PLA and PBS filled with sugarcane fibers and preparation method thereof

Abstract

The invention relates to the technical field of new materials, and discloses a high-performance composite material prepared from PLA and PBS filled with sugarcane fibers and a preparation method of the high-performance composite material, and the high-performance composite material is prepared from the following components in parts by weight: 100 parts of PLA, 25-40 parts of PBS, 15-25 parts of sugarcane fibers, 3-8 parts of a compatilizer and 1-3 parts of a surface lubricant. A byproduct bagasse obtained after sugarcane processing is used as a material, the bagasse contains rich cellulose and hemicellulose, is a biomass resource with huge potential and has high strength and modulus, sugarcane fibers are prepared through a steam explosion technology, then the PLA and PBS / sugarcane fiber composite material is prepared through a dynamic screw extrusion technology, and in the natural environment, the PLA and PBS / sugarcane fiber composite material can be used for preparing the composite material. The material can be naturally decomposed, and the sugarcane fibers are low in cost, so that pollution caused by traditional plastics and the cost of manufacturing materials are reduced, and the comprehensive performance of the PLA material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of new materials, in particular to a high-performance composite material prepared by filling PLA and PBS with sugarcane fiber and a preparation method thereof. Background Art

[0002] Plastic products are ubiquitous in human society. They are widely used to make disposable tableware, outdoor furniture and food containers, etc. However, more than 90% of plastic products end up in landfills or natural environments. It takes more than 400 years for them to decompose in the ocean and 1,000 years in landfills. Therefore, developing a biodegradable material to replace traditional non-degradable fossil-based plastics is conducive to achieving low-carbon and environmentally friendly.

[0003] Traditional PLA (Polylactic Acid) polylactic acid materials are produced and processed from renewable plant starch, and PBS (Polybutylene Succinate) polybutylene succinate is derived from petrochemical materials. Both can be biodegraded in the natural environment, but due to the high price and inherent defects of the materials, their application range is limited. Therefore, it is urgently needed in the current society to modify PLA and PBS and add low-cost renewable materials to replace plastic products such as disposable tableware and food containers. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a high-performance composite material prepared by filling PLA and PBS with sugarcane fiber and a preparation method thereof, which solves the problems of high cost of composite materials and inherent defects of the materials, which limit the scope of application.

[0005] To achieve the above objectives, the present invention is implemented through the following technical scheme: sugarcane fiber is filled with PLA and PBS to prepare a high-performance composite material, which includes the following parts by weight: 100 parts of PLA, 25-40 parts of PBS, 15-25 parts of sugarcane fiber, 3-8 parts of a compatibilizer, and 1-3 parts of a surface lubricant.

[0006] Preferably, the compatibilizer is one of EGMA (ethylene-methyl acrylate copolymer) and PLA-g-MAH (maleic anhydride grafted polylactic acid).

[0007] Preferably, the surface lubricant is one of erucamide and stearic acid.

[0008] The method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber comprises the following steps:

[0009] S1. Dehydration and pretreatment of bagasse: Dehydrating the bagasse, placing the dehydrated bagasse into a mixer, adding xylanase, and stirring;

[0010] S2. Preparation of steam blasting machine: heating the three-screw steam blasting machine and putting the pre-treated bagasse into the blasting machine;

[0011] S3, preparation of sugarcane fiber: adding a filter screen to the die of the blasting machine to prepare sugarcane fiber;

[0012] S4, material addition: adding sugarcane fiber, PLA, PBS, compatibilizer and surface lubricant into the three-screw extruder in proportion;

[0013] S5, extrusion molding: control the extruder feed speed and main machine speed, and control the heating temperature at different positions in the extruder to prepare a composite material of sugarcane fiber filled PLA and PBS

[0014] Preferably, the amount of xylanase added in S1 is 0.5% by weight of bagasse, and the mixer is stirred for 3 to 5 minutes.

[0015] Preferably, the three-screw steam explosion machine in S2 is heated to 200°C.

[0016] Preferably, the filter screen at the die of the blasting machine in S3 is 100 mesh, and 100 mesh sugarcane fiber is prepared.

[0017] Preferably, the extruder feeding speed in S5 is 35 rpm.

[0018] Preferably, the main engine rotates at 185 rpm.

[0019] Preferably, the extruder temperature from the feed end to the die head is set to:

[0020] 80°C-100°C-160°C-170°C-170°C-180°C-180°C-180°C-180°C-180°C-175°C. The invention provides a high-performance composite material prepared by filling PLA and PBS with sugarcane fiber and a preparation method thereof.

[0021] It has the following beneficial effects:

[0022] The present invention uses bagasse, a byproduct of sugarcane processing, as a material. Bagasse is rich in cellulose and hemicellulose, is a biomass resource with great potential, has high strength and modulus, and is used to prepare sugarcane fiber through steam explosion technology. Then, a PLA and PBS sugarcane fiber composite material is prepared through dynamic screw extrusion technology. In a natural environment, the material can be naturally decomposed, and the cost of sugarcane fiber is low, which reduces the pollution caused by traditional plastics and the cost of making materials, and improves the comprehensive performance of PLA materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of a method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Please see attached Figure 1 The embodiment of the present invention provides a high-performance composite material prepared by filling PLA and PBS with sugarcane fiber, comprising the following parts by weight: 100 parts of PLA, 25-40 parts of PBS, 15-25 parts of sugarcane fiber, 3-8 parts of a compatibilizer, and 1-3 parts of a surface lubricant.

[0026] Specifically, PLA is a high-quality polylactic acid material with a high degree of molecular chain regularity, which can give the material excellent initial strength and rigidity. As a core basic component, it is used in relatively large amounts to build a basic mechanical support structure for the entire composite material, ensuring that the material will not be easily deformed under normal conditions of use. At the same time, it has a suitable melt flow rate, which is easy for subsequent extrusion molding, ensuring that it can be fully mixed with PBS and sugarcane fiber during the preparation of the composite material. Natureworks4032D can be used for PLA.

[0027] PBS can significantly improve the overall flexibility of the material. It is tightly interwoven with the relatively rigid PLA molecular chains in the composite material system. During the processing and heating process, it can effectively adjust the rheological properties of the matrix, making the material easier to flow and mix evenly in the blending and extrusion process, ensuring the synergistic effect of each component. At the same time, its molecular structure helps to increase the thermal decomposition temperature of the composite material and improve the overall heat resistance of the material. Blue Mountain Tunhe 801T can be used as PBS.

[0028] The cellulose crystal area inside the sugarcane fiber has high strength and modulus, which can support the entire material structure. At the same time, there are many active groups such as hydroxyl groups on its surface. These groups promote physical entanglement and chemical bonding between the sugarcane fiber and the PLA and PBS matrix, so that it is tightly embedded in the matrix to form a strong support network. In addition, the sugarcane fiber itself is a natural degradable substance. In the natural environment, microorganisms can easily identify and decompose it. In addition, the cost of sugarcane fiber is low, which reduces the pollution caused by traditional plastics and the cost of making materials.

[0029] The addition of compatibilizer can avoid the agglomeration problem of sugarcane fiber due to incompatibility with the matrix, thereby improving the compatibility of PLA, PBS and sugarcane fiber;

[0030] The addition of surface lubricants can make the surface of the final product smoother and flatter, reduce defects such as surface scratches and pitting, and can significantly improve the appearance quality of the material. At the same time, it can improve the fluidity of the material, shorten the processing time, improve production efficiency, and reduce production costs.

[0031] The compatibilizer is one of EGMA and PLA-g-MAH.

[0032] Specifically, EGMA has groups that can interact with the ester groups of PLA and PBS. Due to the high activity of the epoxy group of glycidyl methacrylate, it can undergo a ring-opening reaction with the hydroxyl groups on the surface of sugarcane fiber to achieve chemical bonding, thereby playing a compatibilizing role. PLA-g-MAH undergoes esterification reaction or forms strong interactions such as hydrogen bonds with the ester groups of PBS and the hydroxyl groups of sugarcane fibers. These two compatibilizers, with their unique chemical structure, can accurately target the active sites of different components, allowing the components to be closely integrated.

[0033] The surface lubricant is one of erucamide and stearic acid.

[0034] Specifically, erucamide, with its long carbon chain structure, can effectively reduce the friction between the material and the extruder during the processing process, allowing the mixture of PLA, PBS and sugarcane fiber to be stably transported under the strong push of the screw, avoiding adverse phenomena such as material accumulation and channel blockage caused by friction, thereby ensuring the efficient and stable operation of the entire processing flow. Stearic acid also uses its own long-chain molecular characteristics to exert lubrication efficiency at various key nodes in material processing. From blending extrusion to final molding, it continuously reduces the friction coefficient between the material and the equipment, making the material flow smoother, thereby improving the surface smoothness of the composite material.

[0035] The method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber comprises the following steps:

[0036] S1. Dehydration and pretreatment of bagasse: Dehydrating the bagasse, placing the dehydrated bagasse into a mixer, adding xylanase, and stirring;

[0037] S2. Preparation of steam blasting machine: heating the three-screw steam blasting machine and putting the pre-treated bagasse into the blasting machine;

[0038] S3, preparation of sugarcane fiber: adding a filter screen to the die of the blasting machine to prepare sugarcane fiber;

[0039] S4, material addition: adding sugarcane fiber, PLA, PBS, compatibilizer and surface lubricant into the three-screw extruder in proportion;

[0040] S5, extrusion molding: controlling the extruder feeding speed and the main machine speed, and controlling the heating temperature at different positions in the extruder to prepare a composite material of sugarcane fiber filled PLA and PBS.

[0041] Specifically, in S1, the commercially available bagasse is dehydrated to remove excess water, avoid problems such as material agglomeration and hydrolysis caused by water in subsequent processing, and ensure the accurate mixing ratio of each component. Then, the dehydrated bagasse is placed in a mixer and xylanase is added for stirring, so that the sugarcane fiber is easier to break away from the constraints of lignin, hemicellulose and other components, effectively improving the purity and yield of the subsequent extractable sugarcane fiber, and reserving high-quality reinforcing phases for enhancing the performance of composite materials. At the same time, the microstructure of the enzymatically hydrolyzed bagasse becomes looser, and when it is subsequently blended with PLA and PBS, it can be dispersed more quickly and evenly, thereby improving the overall uniformity of the material and laying a solid foundation for the final preparation of high-performance and stable quality composite materials.

[0042] In S2, the three-screw steam explosion machine is heated to create a high temperature and high pressure environment. After the pre-treated bagasse is put into the blasting machine, the internal water vaporizes instantly, generating internal stress to impact the cell wall, making the lignin and cellulose loose. On the one hand, the sugarcane fiber is fully exposed and the aspect ratio is optimized. Compared with ordinary treatment, the enhancement efficiency is greatly improved, and the tensile strength and rigidity of the material are significantly improved. On the other hand, the blasted bagasse has a regular shape and good dispersion. When mixed with other ingredients, it can be evenly integrated into the matrix, reducing performance defects and helping to manufacture high-performance composite materials.

[0043] In S3, the filter can accurately intercept impurities that are not fully dissociated, lignin clumps and fiber fragments that do not meet the requirements, and only release uniform, high-purity sugarcane fibers, which can stably enhance material properties, avoid stress concentration caused by impurities, and significantly improve mechanical properties such as tensile and bending strength;

[0044] In S5, the feeding speed determines the rate at which the material enters the extruder, and the main engine speed regulates the shear and mixing intensity of the material under the push of the screw, which can not only ensure that the sugarcane fiber, PLA, PBS and other components are fully and evenly mixed, but also avoid material accumulation or uneven dispersion caused by improper speed. At the same time, the heating temperature of the extruder at different positions from the feed end to the die head is set to make the internal structure of the composite material highly uniform and the fiber and matrix tightly combined.

[0045] The amount of xylanase added in S1 is 0.5% of the weight of bagasse, and the mixer is stirred for 3 to 5 minutes.

[0046] Specifically, adding xylanase at 0.5% by weight of sugarcane bagasse can make it easier for sugarcane fiber to break away from the constraints of lignin and other components, thereby improving the purity and yield of the subsequently extractable sugarcane fiber.

[0047] The three-screw steam explosion machine in S2 is heated to 200℃.

[0048] Specifically, the high temperature of 200°C causes the water inside the bagasse to vaporize instantly, generating extremely strong internal stress, which causes the connection between lignin, cellulose and hemicellulose in the bagasse to be deeply destroyed, thereby making the bagasse regular in morphology and structure and having excellent dispersibility. When it is subsequently blended with PLA, PBS and other additives, it can be dissolved into the matrix in an extremely uniform state, effectively reducing performance fluctuations caused by uneven dispersion.

[0049] The filter screen at the die mouth of the blasting machine in S3 is 100 mesh, and 100 mesh sugarcane fiber is prepared.

[0050] Specifically, the filter net accurately intercepts impurities larger than the 100-mesh standard, lignin agglomerates, and irregularly shaped fiber fragments, ensuring that only sugarcane fibers that meet the 100-mesh fineness requirement can pass through smoothly, thereby ensuring the stability of sugarcane fiber preparation.

[0051] In S5, the extruder feed speed is 35 rpm, the main engine speed is 185 rpm, and the extruder temperature from the feed end to the die head is set to:

[0052] 80℃-100℃-160℃-170℃-170℃-180℃-180℃-180℃-180℃-180℃-180℃-175℃.

[0053] Specifically, the material is initially softened at 80°C at the feed end to facilitate subsequent transportation, and as the material moves forward, the temperature gradually increases to the range of 160°C-180°C, providing a suitable thermal environment for the chemical reactions of the components and the dispersion of the fibers in the matrix, promoting compatibility, and finally at 175°C at the die head to ensure that the material maintains good fluidity and is extruded smoothly.

[0054] Embodiment 1

[0055] 100 parts of PLA, 25 parts of PBS, 15 parts of exploded sugarcane fiber, 3 parts of EGMA and 2 parts of erucamide are added into a three-screw extruder according to the proportion. The extruder temperature is 80℃-100℃-160℃-170℃-170℃-180℃-180℃-180℃-180℃-180℃-175℃ (die head), the feeding speed is 35rpm, and the main engine speed is 185rpm to prepare PLA and PBS composite materials filled with sugarcane fiber.

[0056] Embodiment 2

[0057] 100 parts of PLA, 30 parts of PBS, 20 parts of exploded sugarcane fiber, 5 parts of EGMA and 3 parts of erucamide are added into a three-screw extruder according to the proportion. The extruder temperature is 80℃-100℃-160℃-170℃-170℃-180℃-180℃-180℃-180℃-180℃-175℃ (die head), the feeding speed is 35rpm, and the main engine speed is 185rpm to prepare sugarcane fiber filled PLA and PBS composite materials.

[0058] Embodiment 3

[0059] 100 parts of PLA, 35 parts of PBS, 25 parts of exploded sugarcane fiber, 5 parts of EVA-g-GMA and 2 parts of stearic acid are added into a three-screw extruder according to proportion. The extruder temperature is 80℃-100℃-160℃-170℃-170℃-180℃-180℃-180℃-180℃-180℃-175℃ (die head), the feeding speed is 35rpm, and the main engine speed is 185rpm to prepare sugarcane fiber-filled PLA and PBS composite materials.

[0060] Embodiment 4

[0061] 100 parts of PLA, 40 parts of PBS, 20 parts of exploded sugarcane fiber, 8 parts of EVA-g-GMA and 3 parts of erucamide are added into a three-screw extruder according to proportion. The extruder temperature is 80℃-100℃-160℃-170℃-170℃-180℃-180℃-180℃-180℃-180℃-175℃ (die head), the feeding speed is 35rpm, and the main engine speed is 185rpm to prepare sugarcane fiber-filled PLA and PBS composite materials.

[0062] Table 1

[0063] sample <![CDATA[Density (g / cm 3 )]]> Tensile strength(MPa) Elongation at break (%) Notched impact strength J / m Traditional PLA 1.250 48 6.5 25 Example 1 1.255 50.8 124 75 Example 2 1.255 49.5 132 79 Example 3 1.261 45.8 175 87 Example 4 1.255 46.6 185 98

[0064] Compared with traditional plastic modification, the sugarcane fiber filled PLA and PBS to prepare high-performance composite materials can improve the comprehensive performance of PLA materials.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Sugarcane fiber filled PLA and PBS to prepare high-performance composite materials, characterized in that: The invention comprises the following parts by weight: 100 parts of PLA, 25-40 parts of PBS, 15-25 parts of sugarcane fiber, 3-8 parts of compatibilizer and 1-3 parts of surface lubricant.

2. According to claim 1, the high-performance composite material prepared by filling PLA and PBS with sugarcane fiber is characterized in that: The compatibilizer is one of EGMA and PLA-g-MAH.

3. According to claim 1, the high-performance composite material prepared by filling PLA and PBS with sugarcane fiber is characterized in that: The surface lubricant is one of erucamide and stearic acid.

4. A method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber, characterized in that: The method for preparing a high-performance composite material by filling PLA and PBS with the sugarcane fiber according to any one of claims 1 to 3 comprises the following steps: S1. Dehydration and pretreatment of bagasse: Dehydrating the bagasse, placing the dehydrated bagasse into a mixer, adding xylanase, and stirring; S2. Preparation of steam blasting machine: heating the three-screw steam blasting machine and putting the pre-treated bagasse into the blasting machine; S3, preparation of sugarcane fiber: adding a filter screen to the die of the blasting machine to prepare sugarcane fiber; S4, material addition: adding sugarcane fiber, PLA, PBS, compatibilizer and surface lubricant into the three-screw extruder in proportion; S5, extrusion molding: controlling the extruder feeding speed and the main machine speed, and controlling the heating temperature at different positions in the extruder to prepare a composite material of sugarcane fiber-filled PLA and PBS.

5. The method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber according to claim 4, characterized in that: The amount of xylanase added in S1 is 0.5% of the weight of bagasse, and the mixer is stirred for 3 to 5 minutes.

6. The method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber according to claim 4, characterized in that: The three-screw steam explosion machine in S2 is heated to 200°C.

7. The method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber according to claim 4, characterized in that: The filter screen added to the die of the blasting machine in S3 is 100 mesh, and 100 mesh sugarcane fiber is prepared.

8. The method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber according to claim 4, characterized in that: The extruder feeding speed in S5 is 35 rpm.

9. The method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber according to claim 4, characterized in that: The main engine speed in the S5 is 185 rpm.

10. The method for preparing a high-performance composite material by filling PLA and PBS with sugarcane fiber according to claim 4, characterized in that: The temperature of the extruder in S5 from the feed end to the die head is set to: 80℃-100℃-160℃-170℃-170℃-180℃-180℃-180℃-180℃-180℃-175℃。

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