High-toughness bamboo-plastic composite material and preparation method thereof
By using plasma etching, silane coupling agent treatment, and epoxy resin coating, combined with low-temperature gradient process and toughening agent, the interfacial bonding force of bamboo-plastic composite material is improved, solving the problem of weak bonding force between bamboo raw material and plastic matrix, and significantly improving the impact resistance of the material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANTOU CARNIVAL PLASTIC PROD CO LTD
- Filing Date
- 2026-03-03
- Publication Date
- 2026-04-14
AI Technical Summary
Existing bamboo-plastic composite materials have low toughness, making it difficult to meet the impact resistance requirements of high-end applications. This is mainly due to the weak interfacial bonding between bamboo raw materials and the plastic matrix, which easily leads to stress concentration and crack propagation at the interface.
A hydrophobic transition layer rich in epoxy groups is constructed by activating the surface of bamboo powder through plasma etching, chemically anchoring with silane coupling agent and coating with liquid epoxy resin; combined with low temperature gradient process, block copolymer compatibilization and elastomer toughening, nano-montmorillonite inhibits crack propagation, and finally, ultrafine talc powder and polyethylene glycol are introduced to improve the interface structure.
It significantly improves the impact resistance of bamboo-plastic composite materials. Through chemical cross-linking and the formation of nanoscale transcrystalline layers, it eliminates the amorphous weakness at the interface, realizes the efficient transfer of stress from the bamboo skeleton to the toughened matrix, and improves the overall impact resistance of the material.
Smart Images
Figure CN121851663A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of natural materials technology, belonging to patent classification number C08L97 / 02, specifically to a high-toughness bamboo-plastic composite material and its preparation method. Background Technology
[0002] Bamboo-plastic composites are a new type of polymer composite material made by melt blending bamboo powder, bamboo fiber, and other bamboo raw materials with a plastic matrix as the main raw materials. my country has abundant bamboo resources, a short bamboo growth cycle, and strong renewability. The development and utilization of this material not only realizes the high-value utilization of bamboo resources but also effectively disposes of agricultural and forestry waste, aligning with the concept of green and environmentally friendly development. Bamboo-plastic composites combine the texture and corrosion-resistant and insect-proof properties of natural bamboo with the processability and dimensional stability of plastics, and are widely used in many fields such as outdoor landscaping materials, interior decoration, packaging and transportation, and municipal facilities, becoming one of the research hotspots in the field of polymer composites in recent years. However, existing bamboo-plastic composites generally suffer from the technical defect of low toughness, making it difficult to meet the impact resistance requirements of high-end applications. This has become a key bottleneck restricting its industrial upgrading and application expansion. Bamboo raw material is a natural polymer material with a surface rich in hydrophilic groups such as hydroxyl groups. It has a significant difference in polarity with the hydrophobic plastic matrix, resulting in poor interfacial compatibility. The two are mostly physically and mechanically bonded together, with weak interfacial bonding force. Under stress, stress concentration is easily generated at the interface, which in turn triggers the initiation and rapid propagation of cracks, ultimately leading to a significant decrease in the material's impact toughness. Summary of the Invention
[0003] The purpose of this invention is to provide a high-toughness bamboo-plastic composite material and its preparation method, so as to solve the technical problems mentioned in the background art.
[0004] To achieve the above objectives, the present invention provides the following technical solution:
[0005] A method for preparing a high-toughness bamboo-plastic composite material includes the following steps:
[0006] (1) After mixing ultrafine bamboo powder and bamboo fiber, plasma treatment is performed to obtain etched bamboo raw material;
[0007] (2) The etched bamboo raw material is mixed with silane coupling agent KH-560 to obtain silanized bamboo raw material;
[0008] (3) The silanized bamboo raw material was mixed with liquid bisphenol A epoxy resin and accelerator DMP-30 to obtain a modified bamboo composite substrate.
[0009] (4) Polylactic acid, polybutylene succinate and polycaprolactone are melt-blended to obtain a plastic blend;
[0010] (5) Add PLA-b-PBS block copolymer to plastic blend and carry out melt grafting reaction to obtain compatibilized plastic matrix;
[0011] (6) PCL-g-GMA elastomer and organomontmorillonite were added to the compatibilized plastic matrix and melt-blended to obtain a modified degradable plastic matrix;
[0012] (7) The modified bamboo composite substrate obtained in step (3), the modified degradable plastic matrix obtained in step (6), maleic anhydride grafted polylactic acid compatibilizer, antioxidant 1010, calcium stearate lubricant, ultrafine talc powder and polyethylene glycol are mixed and extruded to obtain a high-toughness bamboo-plastic composite material.
[0013] In the technical solution of this invention, the toughness of bamboo-plastic composite material is improved synergistically from the following aspects: (1) First, the surface of bamboo raw material is physically bombarded by argon plasma etching to remove the weak boundary layer of lignin and form micro-pits, thereby increasing the specific surface area and introducing free radical active sites and exposing more cellulose hydroxyl groups, which solves the problem of low surface activity and few binding sites of bamboo raw material; then, the hydrolyzed silanol groups of silane coupling agent KH-560 undergo dehydration condensation with the hydroxyl groups on the surface of bamboo to form Si-OC covalent bonds, and oleophilic epoxy functional groups are grafted onto the hydrophilic bamboo surface, eliminating the strong water absorption of bamboo material and providing stable chemical bonding anchors for subsequent resin coating, avoiding The bamboo substrate and the plastic matrix separate at the interface due to their polarity difference. Finally, utilizing the good flowability and wettability of liquid bisphenol A epoxy resin, ring-opening crosslinking with the residual active sites on the bamboo surface is achieved with the assistance of epoxy anchors, forming a nanoscale resin coating transition layer. This not only repairs the structural defects on the bamboo powder surface and eliminates the stress concentration points of the bamboo substrate itself, improving the intrinsic toughness of the bamboo substrate, but also constructs a hydrophobic barrier. At the same time, it retains a large number of epoxy groups, providing a functional group basis for subsequent chemical crosslinking with the plastic matrix. This fundamentally solves the problems of weak interfacial bonding between the bamboo substrate and the plastic matrix, and the tendency for stress concentration at the interface under stress, leading to a decrease in toughness. (2) A low-temperature gradient premixing process was designed to address the different melting point characteristics of PLA, PBS, and PCL. Under the premise of preventing thermal degradation of the heat-sensitive components PCL and PLA and avoiding polymer chain breakage, the three crystalline polymers were uniformly physical blended through screw mechanical shearing, initially constructing a stable multiphase coexistence matrix structure and ensuring the structural integrity of the matrix itself. Then, PLA-b-PBS block copolymer was added as an amphiphilic macromolecular surfactant. Its different segments were inserted into the corresponding plastic phase regions, reducing interphase surface tension, refining the dispersed phase particle size, effectively preventing matrix phase separation, and constructing a uniform continuous phase structure. This provided a smooth path for rapid stress transmission under stress, avoiding localized stress caused by phase separation. Force concentration; finally, PCL-g-GMA elastomer and organomontmorillonite are added for synergistic toughening. The epoxy groups in the elastomer react with the terminal carboxyl groups of PLA / PBS to generate elastic particles in situ. Under stress, these particles can induce a large number of crazes and absorb impact energy. At the same time, moderate shear force expands the interlayer spacing of montmorillonite to achieve exfoliation and intercalation. The nanosheets can effectively inhibit the initiation and propagation of cracks. The two form a synergistic toughening effect of energy absorption and crack resistance. Meanwhile, the screw speed is strictly controlled to avoid polymer degradation caused by excessive shear heat. Finally, the notched impact strength of the plastic matrix is significantly improved, giving the matrix itself good impact resistance and stress dispersion capabilities. It can effectively bear and disperse the stress transmitted by the bamboo substrate and avoid material fracture caused by local stress overload.
[0014] Preferably, in step (1), the mass ratio of ultrafine bamboo powder to bamboo fiber is 4:(1-2).
[0015] Preferably, in step (2), the amount of silane coupling agent KH-560 added is 3 to 5 wt% of the bamboo raw material being etched.
[0016] Preferably, in step (3), the amount of liquid bisphenol A epoxy resin used is 4 to 6 wt% of the silanized bamboo raw material.
[0017] Preferably, in step (4), the mass ratio of polylactic acid, polybutylene succinate, and polycaprolactone is 4:(2-4):(0.5-1).
[0018] Preferably, in step (5), the amount of PLA-b-PBS block copolymer added is 4 to 8 wt% of the plastic blend.
[0019] Preferably, in step (6), the amount of PCL-g-GMA elastomer added is 3 to 5 wt% of the compatibilized plastic matrix.
[0020] Preferably, in step (6), the amount of organic montmorillonite added is 1 to 3 wt% of the compatibilizing plastic matrix.
[0021] Preferably, in step (7), the mass ratio of ultrafine talc to polyethylene glycol is 1.5:(0.4-0.6).
[0022] The present invention found in experiments that although chemical bonding between bamboo substrate and plastic matrix was achieved, the epoxy resin coating layer on the surface of bamboo powder has a smooth and rigid amorphous state and lacks the ability to induce crystallization. As a result, the semi-crystalline degradable plastic matrix (PLA / PBS) is difficult to fold and arrange in an orderly manner at the interface during the melting and cooling process. It is very easy to form a micron-sized amorphous void layer between bamboo powder and matrix. This region has low modulus and loose structure, which becomes the blocking point of stress transmission and the preferred path for crack propagation, which seriously limits the further improvement of material toughness. To address this technical problem, this invention introduces ultrafine talc powder and polyethylene glycol (PEG-600) during the composite cold mixing stage. PEG-600, with its high wettability due to its small molecules, preferentially accumulates at the interface, significantly enhancing the mobility of polymer chain segments near the interface by reducing inter-chain friction. This provides conformational adjustment space for crystal arrangement. Simultaneously, ultrafine talc powder, acting as a highly efficient heterogeneous nucleating agent, adheres to the surface of the bamboo powder epoxy layer, becoming a highly active crystal growth point. The two work synergistically to induce the matrix molecular chains to grow a dense interfacial transcrystalline layer perpendicular to the interface, using bamboo powder as a substrate. This transcrystalline layer acts like countless tiny physical rivets, tightly stitching the bamboo substrate to the plastic matrix, completely eliminating the amorphous weakness at the interface, and achieving efficient stress transfer from the bamboo skeleton to the toughened matrix, significantly improving the overall impact resistance of the composite material.
[0023] A high-toughness bamboo-plastic composite material is prepared by the method described above.
[0024] Compared with the prior art, the beneficial effects of the present invention are:
[0025] 1. By activating the surface of bamboo powder through plasma etching, followed by chemical anchoring with a silane coupling agent and coating with liquid epoxy resin, a hydrophobic transition layer rich in epoxy groups is constructed on the surface of the bamboo substrate. This layer not only repairs the defects of the bamboo powder itself, but also forms a strong chemical cross-link with the plastic matrix, fundamentally avoiding interface separation and stress concentration.
[0026] 2. For multi-component degradable plastics, a low-temperature gradient process is used to avoid thermal degradation, and the dispersed phase is refined by compatibilizing with block copolymers to construct a uniform and continuous structure. At the same time, elastomers are introduced to absorb impact energy and nano-montmorillonite is introduced to inhibit crack propagation. The two work synergistically to significantly improve the impact resistance of the plastic matrix and provide an efficient pathway for stress transfer.
[0027] 3. In the composite granulation stage, ultrafine talc and polyethylene glycol are introduced. Polyethylene glycol enhances the interfacial molecular chain mobility, while ultrafine talc acts as a nucleating agent to induce the growth of a dense transcrystalline layer perpendicular to the interface on the bamboo powder surface of the plastic matrix. This transcrystalline layer acts like countless physical rivets, tightly stitching the bamboo skeleton to the toughened matrix, completely eliminating the amorphous weak areas at the interface, and further improving toughness. Attached Figure Description
[0028] Figure 1 This is a low-magnification SEM image of the high-toughness bamboo-plastic composite material prepared in Example 1 of the present invention.
[0029] Figure 2 This is a medium-magnification SEM image of the high-toughness bamboo-plastic composite material prepared in Example 1 of the present invention.
[0030] Figure 3 This is a high-magnification SEM image of the high-toughness bamboo-plastic composite material prepared in Example 1 of the present invention.
[0031] Figure 4 The image shows the XPS spectrum of the high-toughness bamboo-plastic composite material prepared in Example 1 of this invention.
[0032] Figure 5 The image shows the XRD pattern of the high-toughness bamboo-plastic composite material prepared in Example 1 of this invention. Detailed Implementation
[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0034] Example 1
[0035] A method for preparing a high-toughness bamboo-plastic composite material includes the following steps:
[0036] Step 1: Mix 80 parts by weight of dried ultrafine bamboo powder with 35 parts by weight of bamboo fiber evenly, remove impurities by airflow pulverization, and place in a vacuum drying oven. Dry under vacuum at 85℃ for 12 hours, controlling the material moisture content to ≤1.0wt%. Then, place the dried bamboo mixture into a plasma treatment instrument, introduce argon gas to create an oxygen-free atmosphere, set the discharge power to 350W, and the treatment time to 6 minutes to perform surface etching treatment on the bamboo material to obtain etched bamboo material.
[0037] Step 2: Put all the above-mentioned etched bamboo raw materials into a high-speed mixer, add the pretreated silane coupling agent KH-560 (pretreatment conditions are: mix KH-560 and deionized water at a volume ratio of 1:6, adjust the pH to 4.5 with acetic acid, and hydrolyze at 35℃ for 30 min), the amount of silane coupling agent KH-560 is 4.5 wt% of the etched bamboo raw materials; set the mixer speed to 600 r / min and the reaction temperature to 105℃, and mix and react under these conditions at a constant temperature and speed for 40 min to obtain silanized bamboo raw materials.
[0038] Step 3: Keep the high-speed mixer running and spray 5.5% by weight of liquid bisphenol A epoxy resin E-51 and 0.5% by weight of accelerator DMP-30 into the silanized bamboo raw material; adjust the mixer speed to 800 r / min, maintain the temperature at 110℃, and stir at high speed for 20 min; after the reaction is completed, take out the material and place it in an 80℃ oven for heat treatment for 2 h to obtain the modified bamboo composite substrate.
[0039] Step 4: Add 40 parts by weight of polylactic acid (PLA), 35 parts by weight of polybutylene succinate (PBS), and 9 parts by weight of polycaprolactone (PCL) to a twin-screw mixer; set the temperature of the mixer to 135°C in zone 1, 155°C in zone 2, and 170°C in zone 3, and set the screw speed to 180 r / min. Under these conditions, melt-blend for 10 min to obtain a plastic blend.
[0040] Step 5: Add 7% by mass of PLA-b-PBS block copolymer to the plastic blend in the twin-screw mixer; finely adjust the temperature of the three zones of the mixer to 175℃ and increase the screw speed to 220r / min, and carry out the melt grafting reaction for 15min under these conditions to obtain the compatibilized plastic matrix.
[0041] Step 6: Add 4.5% by weight of PCL-g-GMA elastomer and 2.5% by weight of organomontmorillonite to the compatibilized plastic matrix; maintain the temperature at 175℃, adjust the screw speed to 240r / min, continue melt blending for 25min, and obtain the modified degradable plastic matrix by extrusion granulation.
[0042] Step 7: Weigh 40 parts by weight of the modified bamboo composite matrix obtained in Step 3, 45 parts by weight of the modified degradable plastic matrix obtained in Step 6, 3 parts by weight of maleic anhydride-grafted polylactic acid compatibilizer, 0.3 parts by weight of antioxidant 1010, 2 parts by weight of calcium stearate lubricant, 1.5 parts by weight of ultrafine talc powder (1250 mesh), and 0.55 parts by weight of polyethylene glycol PEG-600; put all the above raw materials into an SHR high-speed mixer, set the speed to 500 r / min, control the mixing temperature to ≤45℃, and dry mix for 8 min; then put the mixture into a twin-screw extruder, set the temperatures of the first to fourth zones of the extruder to 150℃, 165℃, 175℃, and 175℃ respectively, the die head temperature to 170℃, the screw speed to 200 r / min, and the extrusion pressure to 20 MPa. After extrusion, air cooling and hot cutting, the material is dried at 60℃ to constant weight to obtain a high-toughness bamboo-plastic composite material.
[0043] Example 2
[0044] A method for preparing a high-toughness bamboo-plastic composite material includes the following steps:
[0045] Step 1: Mix 80 parts by weight of dried ultrafine bamboo powder with 25 parts by weight of bamboo fiber evenly, remove impurities by airflow pulverization, and place in a vacuum drying oven. Dry under vacuum at 85℃ for 12 hours, controlling the material moisture content to ≤1.0wt%. Then, place the dried bamboo mixture into a plasma treatment instrument, introduce argon gas to create an oxygen-free atmosphere, set the discharge power to 350W, and the treatment time to 6 minutes to perform surface etching treatment on the bamboo material to obtain etched bamboo material.
[0046] Step 2: Put all the above-mentioned etched bamboo raw materials into a high-speed mixer, add the pretreated silane coupling agent KH-560 (pretreatment conditions are: mix KH-560 and deionized water at a volume ratio of 1:6, adjust the pH to 4.5 with acetic acid, and hydrolyze at 35℃ for 30 min), the amount of silane coupling agent KH-560 is 3.5 wt% of the etched bamboo raw materials; set the mixer speed to 600 r / min and the reaction temperature to 105℃, and mix and react under these conditions at a constant temperature and speed for 40 min to obtain silanized bamboo raw materials.
[0047] Step 3: Keep the high-speed mixer running and spray 4.5% by weight of liquid bisphenol A epoxy resin E-51 and 0.5% by weight of accelerator DMP-30 into the silanized bamboo raw material; adjust the mixer speed to 800 r / min, maintain the temperature at 110℃, and stir at high speed for 20 min; after the reaction is completed, take out the material and place it in an 80℃ oven for heat treatment for 2 h to obtain the modified bamboo composite substrate.
[0048] Step 4: Add 40 parts by weight of polylactic acid (PLA), 25 parts by weight of polybutylene succinate (PBS), and 6 parts by weight of polycaprolactone (PCL) to a twin-screw mixer; set the temperature of the mixer zone 1 to 135℃, zone 2 to 155℃, and zone 3 to 170℃, and the screw speed to 180 r / min. Under these conditions, melt-blend for 10 min to obtain a plastic blend.
[0049] Step 5: Add 5% by mass of PLA-b-PBS block copolymer to the plastic blend in the twin-screw mixer; finely adjust the temperature of the three zones of the mixer to 175℃ and increase the screw speed to 220r / min, and carry out the melt grafting reaction for 15min under these conditions to obtain the compatibilized plastic matrix.
[0050] Step 6: Add 3.5% by weight of PCL-g-GMA elastomer and 1.5% by weight of organomontmorillonite to the compatibilized plastic matrix; maintain the temperature at 175℃, adjust the screw speed to 240r / min, continue melt blending for 25min, and obtain the modified degradable plastic matrix by extrusion granulation.
[0051] Step 7: Weigh 40 parts by weight of the modified bamboo composite matrix obtained in Step 3, 45 parts by weight of the modified degradable plastic matrix obtained in Step 6, 3 parts by weight of maleic anhydride-grafted polylactic acid compatibilizer, 0.3 parts by weight of antioxidant 1010, 2 parts by weight of calcium stearate lubricant, 1.5 parts by weight of ultrafine talc powder (1250 mesh), and 0.45 parts by weight of polyethylene glycol PEG-600; put all the above raw materials into an SHR high-speed mixer, set the speed to 500 r / min, control the mixing temperature to ≤45℃, and dry mix for 8 min; then put the mixture into a twin-screw extruder, set the temperatures of the first to fourth zones of the extruder to 150℃, 165℃, 175℃, and 175℃ respectively, the die head temperature to 170℃, the screw speed to 200 r / min, and the extrusion pressure to 20 MPa. After extrusion, air cooling and hot cutting, the material is dried at 60℃ to constant weight to obtain a high-toughness bamboo-plastic composite material.
[0052] Example 3
[0053] A method for preparing a high-toughness bamboo-plastic composite material includes the following steps:
[0054] Step 1: Mix 80 parts by weight of dried ultrafine bamboo powder with 30 parts by weight of bamboo fiber evenly, remove impurities by airflow pulverization, and place in a vacuum drying oven. Vacuum dry at 85℃ for 12 hours, controlling the material moisture content to ≤1.0wt%. Then, place the dried bamboo mixture into a plasma treatment instrument, introduce argon gas to create an oxygen-free atmosphere, set the discharge power to 350W, and the treatment time to 6 minutes to perform surface etching treatment on the bamboo material to obtain etched bamboo material.
[0055] Step 2: Put all the above-mentioned etched bamboo raw materials into a high-speed mixer, add the pretreated silane coupling agent KH-560 (pretreatment conditions are: mix KH-560 and deionized water at a volume ratio of 1:6, adjust the pH to 4.5 with acetic acid, and hydrolyze at 35℃ for 30 min), the amount of silane coupling agent KH-560 is 4wt% of the etched bamboo raw materials; set the mixer speed to 600 r / min and the reaction temperature to 105℃, and mix and react under these conditions at a constant temperature and speed for 40 min to obtain silanized bamboo raw materials.
[0056] Step 3: Keep the high-speed mixer running and spray 5% by weight of liquid bisphenol A epoxy resin E-51 and 0.5% by weight of accelerator DMP-30 into the silanized bamboo raw material; adjust the mixer speed to 800 r / min, maintain the temperature at 110℃, and stir at high speed for 20 min; after the reaction is completed, take out the material and place it in an 80℃ oven for heat treatment for 2 h to obtain the modified bamboo composite substrate.
[0057] Step 4: Add 40 parts by weight of polylactic acid (PLA), 30 parts by weight of polybutylene succinate (PBS), and 7 parts by weight of polycaprolactone (PCL) to a twin-screw mixer; set the temperature of the mixer zone 1 to 135℃, zone 2 to 155℃, and zone 3 to 170℃, and the screw speed to 180 r / min. Under these conditions, melt-blend for 10 min to obtain a plastic blend.
[0058] Step 5: Add 6% by mass of PLA-b-PBS block copolymer to the plastic blend in the twin-screw mixer; finely adjust the temperature of the three zones of the mixer to 175℃ and increase the screw speed to 220r / min, and carry out the melt grafting reaction for 15min under these conditions to obtain the compatibilized plastic matrix.
[0059] Step 6: Add 4% by weight of PCL-g-GMA elastomer and 2% by weight of organomontmorillonite to the compatibilized plastic matrix; maintain the temperature at 175℃, adjust the screw speed to 240r / min, continue melt blending for 25min, and obtain the modified degradable plastic matrix by extrusion granulation.
[0060] Step 7: Weigh 40 parts by weight of the modified bamboo composite matrix obtained in Step 3, 45 parts by weight of the modified degradable plastic matrix obtained in Step 6, 3 parts by weight of maleic anhydride-grafted polylactic acid compatibilizer, 0.3 parts by weight of antioxidant 1010, 2 parts by weight of calcium stearate lubricant, 1.5 parts by weight of ultrafine talc powder (1250 mesh), and 0.5 parts by weight of polyethylene glycol PEG-600; put all the above raw materials into an SHR high-speed mixer, set the speed to 500 r / min, control the mixing temperature to ≤45℃, and dry mix for 8 min; then put the mixture into a twin-screw extruder, set the temperatures of the first to fourth zones of the extruder to 150℃, 165℃, 175℃, and 175℃ respectively, the die head temperature to 170℃, the screw speed to 200 r / min, and the extrusion pressure to 20 MPa. After extrusion, air cooling and hot cutting, the material is dried at 60℃ to constant weight to obtain a high-toughness bamboo-plastic composite material.
[0061] Example 4
[0062] A method for preparing a high-toughness bamboo-plastic composite material includes the following steps:
[0063] Step 1: Mix 80 parts by weight of dried ultrafine bamboo powder with 40 parts by weight of bamboo fiber evenly, remove impurities by airflow pulverization, and place in a vacuum drying oven. Dry under vacuum at 85℃ for 12 hours, controlling the material moisture content to ≤1.0wt%. Then, place the dried bamboo mixture into a plasma treatment instrument, introduce argon gas to create an oxygen-free atmosphere, set the discharge power to 350W, and the treatment time to 6 minutes to perform surface etching on the bamboo material to obtain etched bamboo material.
[0064] Step 2: Put all the above-mentioned etched bamboo raw materials into a high-speed mixer, add the pretreated silane coupling agent KH-560 (pretreatment conditions are: mix KH-560 and deionized water at a volume ratio of 1:6, adjust the pH to 4.5 with acetic acid, and hydrolyze at 35℃ for 30 min), the amount of silane coupling agent KH-560 is 5wt% of the etched bamboo raw materials; set the mixer speed to 600 r / min and the reaction temperature to 105℃, and mix and react under these conditions at a constant temperature and speed for 40 min to obtain silanized bamboo raw materials.
[0065] Step 3: Keep the high-speed mixer running and spray 6% by weight of liquid bisphenol A epoxy resin E-51 and 0.5% by weight of accelerator DMP-30 into the silanized bamboo raw material; adjust the mixer speed to 800 r / min, maintain the temperature at 110℃, and stir at high speed for 20 min; after the reaction is completed, take out the material and place it in an 80℃ oven for heat treatment for 2 h to obtain the modified bamboo composite substrate.
[0066] Step 4: Add 40 parts by weight of polylactic acid (PLA), 40 parts by weight of polybutylene succinate (PBS), and 10 parts by weight of polycaprolactone (PCL) to a twin-screw mixer; set the temperature of the mixer to 135℃ in zone 1, 155℃ in zone 2, and 170℃ in zone 3, and set the screw speed to 180 r / min. Under these conditions, melt-blend for 10 min to obtain a plastic blend.
[0067] Step 5: Add 8% by mass of PLA-b-PBS block copolymer to the plastic blend in the twin-screw mixer; finely adjust the temperature of the three zones of the mixer to 175℃ and increase the screw speed to 220r / min, and carry out the melt grafting reaction for 15min under these conditions to obtain the compatibilized plastic matrix.
[0068] Step 6: Add 5% by weight of PCL-g-GMA elastomer and 3% by weight of organomontmorillonite to the compatibilized plastic matrix; maintain the temperature at 175℃, adjust the screw speed to 240r / min, continue melt blending for 25min, and obtain the modified degradable plastic matrix by extrusion granulation.
[0069] Step 7: Weigh 40 parts by weight of the modified bamboo composite matrix obtained in Step 3, 45 parts by weight of the modified degradable plastic matrix obtained in Step 6, 3 parts by weight of maleic anhydride-grafted polylactic acid compatibilizer, 0.3 parts by weight of antioxidant 1010, 2 parts by weight of calcium stearate lubricant, 1.5 parts by weight of ultrafine talc powder (1250 mesh), and 0.6 parts by weight of polyethylene glycol PEG-600; put all the above raw materials into an SHR high-speed mixer, set the speed to 500 r / min, control the mixing temperature to ≤45℃, and dry mix for 8 min; then put the mixture into a twin-screw extruder, set the temperatures of the first to fourth zones of the extruder to 150℃, 165℃, 175℃, and 175℃ respectively, the die head temperature to 170℃, the screw speed to 200 r / min, and the extrusion pressure to 20 MPa. After extrusion, air cooling and hot cutting, the material is dried at 60℃ to constant weight to obtain a high-toughness bamboo-plastic composite material.
[0070] Example 5
[0071] A method for preparing a high-toughness bamboo-plastic composite material includes the following steps:
[0072] Step 1: Mix 80 parts by weight of dried ultrafine bamboo powder with 20 parts by weight of bamboo fiber evenly, remove impurities by airflow pulverization, and place in a vacuum drying oven. Dry under vacuum at 85℃ for 12 hours, controlling the material moisture content to ≤1.0wt%. Then, place the dried bamboo mixture into a plasma treatment instrument, introduce argon gas to create an oxygen-free atmosphere, set the discharge power to 350W, and the treatment time to 6 minutes to perform surface etching on the bamboo material to obtain etched bamboo material.
[0073] Step 2: Put all the above-mentioned etched bamboo raw materials into a high-speed mixer, add the pretreated silane coupling agent KH-560 (pretreatment conditions are: mix KH-560 and deionized water at a volume ratio of 1:6, adjust the pH to 4.5 with acetic acid, and hydrolyze at 35℃ for 30 min), the amount of silane coupling agent KH-560 is 3wt% of the etched bamboo raw materials; set the mixer speed to 600 r / min and the reaction temperature to 105℃, and mix and react under these conditions at a constant temperature and speed for 40 min to obtain silanized bamboo raw materials.
[0074] Step 3: Keep the high-speed mixer running and spray 4% by weight of liquid bisphenol A epoxy resin E-51 and 0.5% by weight of accelerator DMP-30 into the silanized bamboo raw material; adjust the mixer speed to 800 r / min, maintain the temperature at 110℃, and stir at high speed for 20 min; after the reaction is completed, take out the material and place it in an 80℃ oven for heat treatment for 2 h to obtain the modified bamboo composite substrate.
[0075] Step 4: Add 40 parts by weight of polylactic acid (PLA), 20 parts by weight of polybutylene succinate (PBS), and 5 parts by weight of polycaprolactone (PCL) to a twin-screw mixer; set the temperature of the mixer zone 1 to 135℃, zone 2 to 155℃, and zone 3 to 170℃, and the screw speed to 180 r / min. Under these conditions, melt-blend for 10 min to obtain a plastic blend.
[0076] Step 5: Add 4% by mass of PLA-b-PBS block copolymer to the plastic blend in the twin-screw mixer; finely adjust the temperature of the three zones of the mixer to 175℃ and increase the screw speed to 220r / min, and carry out the melt grafting reaction for 15min under these conditions to obtain the compatibilized plastic matrix.
[0077] Step 6: Add 3% by mass of PCL-g-GMA elastomer and 1% by mass of organomontmorillonite to the compatibilized plastic matrix; maintain the temperature at 175℃, adjust the screw speed to 240r / min, continue melt blending for 25min, and obtain the modified degradable plastic matrix by extrusion granulation.
[0078] Step 7: Weigh 40 parts by weight of the modified bamboo composite matrix obtained in Step 3, 45 parts by weight of the modified degradable plastic matrix obtained in Step 6, 3 parts by weight of maleic anhydride-grafted polylactic acid compatibilizer, 0.3 parts by weight of antioxidant 1010, 2 parts by weight of calcium stearate lubricant, 1.5 parts by weight of ultrafine talc powder (1250 mesh), and 0.4 parts by weight of polyethylene glycol PEG-600; put all the above raw materials into an SHR high-speed mixer, set the speed to 500 r / min, control the mixing temperature to ≤45℃, and dry mix for 8 min; then put the mixture into a twin-screw extruder, set the temperatures of the first to fourth zones of the extruder to 150℃, 165℃, 175℃, and 175℃ respectively, the die head temperature to 170℃, the screw speed to 200 r / min, and the extrusion pressure to 20 MPa. After extrusion, air cooling and hot cutting, the material is dried at 60℃ to constant weight to obtain a high-toughness bamboo-plastic composite material.
[0079] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that steps 1-3 are omitted, and the modified bamboo composite substrate in step 7 is replaced with ordinary bamboo composite substrate (80 parts by weight of ultrafine bamboo powder and 35 parts by weight of bamboo fiber).
[0080] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that steps 5-6 are omitted, and the modified degradable plastic matrix in step 7 is replaced with a common plastic blend.
[0081] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the ultrafine talc powder and polyethylene glycol PEG-600 in step 7 are omitted.
[0082] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that the ultrafine talc powder in step 7 is omitted.
[0083] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that polyethylene glycol PEG-600 in step 7 is omitted.
[0084] Performance testing:
[0085] 1. Notched Impact Strength Test of Simply Supported Beams: The test was conducted according to the national standard GB / T 1043.1-2008 "Determination of Impact Properties of Simply Supported Beams of Plastics - Part 1: Non-Instrumental Impact Testing". Standard specimens with dimensions of 80mm × 10mm × 4mm were prepared, and a type A notch (2mm depth) was machined in the middle of the specimen using a notching sample preparation machine. The test was performed on a simply supported beam impact testing machine with a pendulum energy of 5J and a test temperature of 23℃. Ten specimens were tested in each group, and the maximum and minimum values were discarded before taking the average value. The unit is kJ / m². 2 This indicator is the core data for measuring the toughness of materials. The test results are shown in Table 1.
[0086] 2. Tensile Strength Test: The test was conducted according to the national standard GB / T 1040.2-2006 "Determination of Tensile Properties of Plastics - Part 2: Test Conditions for Molded and Extruded Plastics". The prepared composite material was injection molded into a type I dumbbell-shaped standard tensile specimen and tested on a universal testing machine. The ambient temperature was 23±2℃, the relative humidity was 50±5%, and the tensile speed was set to 10 mm / min. Test data for 5 samples were recorded for each group, and the average value was taken as the final tensile strength result, in MPa. The test results are shown in Table 1.
[0087] 3. Bending Strength Test: The test was conducted according to the national standard GB / T 9341-2008 "Determination of Bending Properties of Plastics". The composite material was prepared into a long strip specimen with dimensions of 80mm × 10mm × 4mm. The test was performed using a universal testing machine with the three-point bending method. The span was set to 64mm, the loading speed was 2mm / min, and the test environment temperature was 23±2℃. Five parallel samples were tested in each group, and the average value was used to calculate the bending strength, in MPa. The test results are shown in Table 1.
[0088] 4. Water Absorption Test: The test was conducted according to the national standard GB / T 1034-2008 "Determination of Water Absorption of Plastics". The sample was cut into square sheets of 50mm × 50mm × 3mm, dried in an oven at 50℃ for 24 hours, cooled to room temperature, and weighed (recorded as m1). Then, it was completely immersed in distilled water at 23℃ for 24 hours. After soaking, it was removed, the surface moisture was blotted with filter paper, and the sample was immediately weighed (recorded as m2). The water absorption rate was calculated using the formula: W = [(m2 - m1) / m1] × 100%. Three parallel samples were tested in each group, and the average value was taken. The test results are shown in Table 1.
[0089] Table 1:
[0090] <![CDATA[Notched impact strength of simply supported beam (kJ / m 2 )]]> Tensile strength (MPa) Bending strength (MPa) 24-hour water absorption rate (%) Example 1 52.6 62.6 95.4 0.32 Example 2 48.3 59.8 91.7 0.35 Example 3 51.8 61.7 94.3 0.34 Example 4 53.2 63.1 96.2 0.38 Example 5 46.5 58.2 89.6 0.36 Comparative Example 1 8.7 29.6 42.3 6.85 Comparative Example 2 15.2 35.8 50.2 0.45 Comparative Example 3 28.9 45.3 68.6 0.39 Comparative Example 4 32.5 48.6 72.3 0.36 Comparative Example 5 30.1 47.2 70.5 0.38
[0091] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a high-toughness bamboo-plastic composite material, characterized in that, Includes the following steps: (1) After mixing ultrafine bamboo powder and bamboo fiber, plasma treatment is performed to obtain etched bamboo raw material; (2) The etched bamboo raw material is mixed with silane coupling agent KH-560 to obtain silanized bamboo raw material; (3) The silanized bamboo raw material was mixed with liquid bisphenol A epoxy resin and accelerator DMP-30 to obtain a modified bamboo composite substrate. (4) Polylactic acid, polybutylene succinate and polycaprolactone are melt-blended to obtain a plastic blend; (5) Add PLA-b-PBS block copolymer to plastic blend and carry out melt grafting reaction to obtain compatibilized plastic matrix; (6) PCL-g-GMA elastomer and organomontmorillonite were added to the compatibilized plastic matrix and melt-blended to obtain a modified degradable plastic matrix; (7) The modified bamboo composite substrate obtained in step (3), the modified degradable plastic matrix obtained in step (6), maleic anhydride grafted polylactic acid compatibilizer, antioxidant 1010, calcium stearate lubricant, ultrafine talc powder and polyethylene glycol are mixed and extruded to obtain a high-toughness bamboo-plastic composite material.
2. The method for preparing a high-toughness bamboo-plastic composite material according to claim 1, characterized in that, In step (1), the mass ratio of ultrafine bamboo powder to bamboo fiber is 4:(1-2).
3. The method for preparing a high-toughness bamboo-plastic composite material according to claim 1, characterized in that, In step (2), the amount of silane coupling agent KH-560 added is 3 to 5 wt% of the bamboo raw material being etched.
4. The method for preparing a high-toughness bamboo-plastic composite material according to claim 1, characterized in that, In step (3), the amount of liquid bisphenol A epoxy resin used is 4 to 6 wt% of the silanized bamboo raw material.
5. The method for preparing a high-toughness bamboo-plastic composite material according to claim 1, characterized in that, In step (4), the mass ratio of polylactic acid, polybutylene succinate, and polycaprolactone is 4:(2-4):(0.5-1).
6. The method for preparing a high-toughness bamboo-plastic composite material according to claim 1, characterized in that, In step (5), the amount of PLA-b-PBS block copolymer added is 4 to 8 wt% of the plastic blend.
7. The method for preparing a high-toughness bamboo-plastic composite material according to claim 1, characterized in that, In step (6), the amount of PCL-g-GMA elastomer added is 3 to 5 wt% of the compatibilized plastic matrix.
8. The method for preparing a high-toughness bamboo-plastic composite material according to claim 1, characterized in that, In step (6), the amount of organic montmorillonite added is 1 to 3 wt% of the compatibilizing plastic matrix.
9. The method for preparing a high-toughness bamboo-plastic composite material according to claim 1, characterized in that, In step (7), the mass ratio of ultrafine talc to polyethylene glycol is 1.5:(0.4-0.6).
10. A high-toughness bamboo-plastic composite material, characterized in that, It is prepared by the method described in any one of claims 1-9 above.