3680 results about "Polylactic acid" patented technology

The invention discloses a polylactic acid injection molding mold based on a gradient heat conduction composite structure and a heat management method thereof, and belongs to the technical field of high polymer material molding processing equipment.The polylactic acid injection molding mold comprises a) a surface high heat conduction layer which is made of a copper-based composite material, has the heat conduction coefficient larger than or equal to 400 W / m.K and is used for rapidly and directionally transferring heat to the surface of a mold cavity; and b) an intermediate transition layer composed of a titanium alloy porous structure. High-efficiency production is realized through innovative design and advanced technology. Integrated metallurgical bonding of the gradient heat conduction structure is achieved through the selective laser melting technology, and the heat flow directivity is enhanced; the dual-mode cooling system is combined with closed-loop temperature control, and the temperature is accurately regulated and controlled; the high-performance material improves the comprehensive performance of the mold; and the structural stability is guaranteed through accurate technological parameters. According to the thermal management method, through multi-physical field simulation optimization, rapid heating and cooling are achieved, the forming period is shortened to 16-18 seconds, the calculation efficiency is improved by 80%, and the production efficiency and the product quality are effectively improved.

The invention belongs to the technical field of biomedical engineering, and particularly relates to a biological rotator cuff patch with a double-gradient structure and a preparation method of the biological rotator cuff patch. The preparation method comprises the following steps: carrying out electrostatic spinning on a spinning solution, controlling the rotating speed of a receiving roller to increase at a constant speed in the electrostatic spinning process, and obtaining a nanofiber membrane after electrostatic spinning; l-polylactic acid and D-polylactic acid are simultaneously dissolved in the spinning solution; the minimum value of the rotating speed of the receiving roller is 100-500 rpm, and the maximum value of the rotating speed of the receiving roller is 3000-4000 rpm. The finally prepared biological rotator cuff patch with the double-gradient structure presents an orientation degree gradient and a piezoelectric effect gradient at the same time on the thickness scale, and has mechanical supporting capacity and biocompatibility, and bionic healing promotion of the patch with the gradient structure is achieved.

A biodegradable polymer composite, a method of making the same and use for same are provided. The biodegradable polymer composite has about 30 to 99.5% by weight of a polymer selected from a group consisting of polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polyhydroxyalkanoates (PHA), and polycaprolactone (PCL) grafted with a compatibilizer selected from a group consisting of maleic anhydride, glycidyl methacrylate, pyromellitic anhydride, acrylic acid, polyacrylic acid, methylene diphenyl diisocyanate, poly(glycidyl methacrylate, copolymer(s) of glycidyl methacrylate; and about 0.5 to 50 % by weight a nano-filler or a micro-filler. The biodegradable polymer composite does not contain polylactic acid. Surfaces of the nano-filler or the micro-filler may be modified using a grafting agent so that the biodegradable polymer composite has enhanced mechanical properties, increased heat resistance, compostablity and / or improved processability. The biodegradable polymer composite may be used to make flexible articles, such as a freezer wrap and a farming sheet.

The invention relates to the technical field of plastic packaging preparation, in particular to an anti-aging plastic packaging material and a preparation method thereof.The anti-aging plastic packaging material is prepared from, by mass, 100-140 parts of polylactic acid, 60-80 parts of PBAT, 2-5 parts of a composite anti-aging agent, 1-2 parts of a lubricant, 2-4 parts of a flame retardant and 3-6 parts of a compatilizer; the composite anti-aging agent comprises a modified anti-aging agent obtained by compounding functionalized montmorillonite and modified silicon dioxide, the functionalized montmorillonite is carnosic acid grafted rare earth ion modified montmorillonite, and the modified silicon dioxide is epoxy methyl oleate grafted silicon dioxide. According to the anti-aging plastic packaging material provided by the invention, a plastic material system with multiple protection mechanisms is constructed through the synergistic effect of all the components, and the prepared plastic packaging material not only keeps good biodegradability, but also has excellent ultraviolet light resistance and oxidation resistance.

The invention discloses a bamboo powder-containing biodegradable plastic for food contact and a preparation method thereof, and relates to the technical field of bio-based materials. The bamboo powder-containing biodegradable plastic for food contact comprises chitosan starch and modified bamboo powder, the chitosan starch is prepared by adding composite chitosan and amino-terminated polyethylene glycol into oxidized corn starch, and the composite chitosan is prepared by grafting chlorogenic acid on the surface of chitosan and then coating succinic anhydride derivatives. The succinic anhydride derivative is prepared from dodecenyl succinic anhydride and 1, 4-butanediamine through a reaction, so that the plastic has the antibacterial property, and meanwhile, the mechanical property is enhanced; the modified bamboo powder is prepared by reacting bamboo powder with a carboxyl-terminated composition, and the carboxyl-terminated composition comprises carboxyl-terminated polylactic acid and carboxyl-terminated polyamide. The toughness of the plastic is enhanced, and the mechanical property of the plastic is further enhanced.

The invention relates to a degradable filter element and a preparation method thereof, and belongs to the technical field of PLA filter elements. The degradable filter element is arranged between an atomizing element shell and a metal heating wire, a plurality of capillary holes are formed in the degradable filter element and used for being filled with tobacco tar, and the degradable filter element is prepared from a degradable composite material through melt spinning. The degradable composite material comprises the following components: polylactic acid and modified silicon dioxide, wherein the modified silicon dioxide is prepared by taking nano silicon dioxide, a silane coupling agent, ferulic acid, amino acid and copper chloride as raw materials, the silicon dioxide is organically modified, so that the dispersity of the silicon dioxide in a polylactic acid system is improved, the interface binding force of the silicon dioxide is improved, and the mechanical property of a polylactic acid material is improved; various antibacterial components are introduced, so that the antibacterial property of the polylactic acid material can be effectively improved.

The invention relates to the technical field of film material preparation, and discloses a polylactic acid antibacterial packaging film and a preparation method thereof, the polylactic acid antibacterial packaging film comprises the following raw material components by weight: 60-80 parts of polylactic acid, 10-20 parts of polyvinyl alcohol, 10-20 parts of nano zinc oxide, 0.5-1.5 parts of nano cellulose, 1-3 parts of an antibacterial agent, and 10-15 parts of corn starch; the antibacterial agent is prepared from the following components in parts by weight: 5-10 parts of carboxymethylated chitosan and 0.5-2 parts of a dynamic disulfide bond cross-linking agent, the substitution degree of the carboxymethylated chitosan is greater than or equal to 80%, the antibacterial agent is prepared from tea tree essential oil and eugenol, and the dynamic disulfide bond cross-linking agent is bis (3-aminopropyl) disulfide. By adopting a composite system of carboxymethylated chitosan and a dynamic disulfide bond cross-linking agent, the technical effects of humidity-triggered self-repairing and mechanical property synergistic improvement are achieved, and compared with a packaging film with a single polymer base material in the prior art, the problem of antibacterial failure caused by mechanical damage is solved.

The invention discloses a high-barrier polycrystalline silicon packaging film and a preparation method thereof, and relates to the technical field of packaging materials. The high-barrier polycrystalline silicon packaging film consists of a polyester film carrier and functional slurry, the functional slurry is prepared from the following raw materials in parts by weight: 15 to 25 parts of ethylene-vinyl alcohol copolymer, 10 to 18 parts of polyvinylidene chloride, 5 to 10 parts of modified nano montmorillonite, 8 to 15 parts of modified polylactic acid, 3 to 6 parts of tributyl citrate, 1 to 3 parts of antioxidant 1010, 1 to 3 parts of ultraviolet light absorber UV-531, 0.5 to 1.5 parts of nucleating agent NA-11, 1 to 2 parts of silane coupling agent KH-550 and 3 to 7 parts of modified silicon dioxide aerogel; 2 to 5 parts of vinyl trimethoxy silane, 1 to 3 parts of nano silver and 20 to 30 parts of deionized water. The high-barrier polycrystalline silicon packaging film has excellent barrier performance, and can effectively block oxygen, water vapor and the like. The polycrystalline silicon packaging film is good in mechanical performance, not prone to damage, antibacterial, antioxidant and anti-ultraviolet, the quality guarantee period of polycrystalline silicon can be prolonged, the product quality can be guaranteed, and the polycrystalline silicon packaging film has great application value in the field of polycrystalline silicon packaging.

Disclosed in the present invention are a high-strength polylactic acid material, a preparation method therefor, and use thereof, belonging to the technical field of macromolecular materials. The high-strength polylactic acid material comprises the following components in parts by weight: 80-90 parts of polylactic acid, 10-20 parts of polybutylene adipate terephthalate, 1-5 parts of a nucleating agent, and 2-5 parts of a compatibilizing agent. The mesh number of the nucleating agent is 1500-2500 mesh; the compatibilizing agent is polycaprolactone, and the intrinsic viscosity thereof is 1.0-3.0 dL / g. The present invention lowers the melting temperature and shortens the melting time of PLA and PBAT, reduces the negative impact of polymer degradation and aging on mechanical properties, produces a heterogeneous nucleation effect, and performs the function of a crystallization nucleus in the cooling crystallization stage, improving crystallization speed and crystallinity, while causing the crystalline phase structure to tend toward a spherulitic state, improving the tensile strength of the polylactic acid material.

The invention relates to the technical field of high-barrier composite packaging films, and discloses a high-barrier composite packaging film with an antibacterial function, which sequentially comprises a base layer, a nano composite barrier layer, an antibacterial functional layer and an outer protective layer from bottom to top, and the layers are tightly attached through a coated starch-based adhesive. According to the high-barrier composite packaging film with the antibacterial function, the cellulose nanowhiskers have the characteristics of high strength and high modulus and are mixed with the bio-based polylactic acid, so that the tensile strength and tear resistance of the bio-based polylactic acid can be remarkably improved, and the structural stability of the packaging film in the using process is guaranteed; nano titanium dioxide and nano cellulose aerogel are arranged in the nano composite barrier layer, so that the barrier property of the packaging film on oxygen and ultraviolet rays can be enhanced, and the packaging film also has a certain antibacterial effect; in addition, the nanocellulose aerogel has a loose porous structure, so that gas molecules can be effectively prevented from passing through, and the barrier property is further improved.

The invention relates to the technical field of degradable fibers, and discloses a degradable bamboo fiber composite material master batch and a preparation method thereof. The composite material is prepared from the following raw materials: modified bamboo fibers, modified polylactic acid, polyadipic acid / butylene terephthalate, a lubricant, an antioxidant and a plasticizer. The preparation method comprises the following steps: 1) performing alkali treatment and tannic acid-metal ion compound modification on the bamboo fibers to form a hydrophobic surface; 2) blending and modifying polylactic acid and bio-based elastomer polyhydroxybutyrate to construct a tough matrix; and 3) carrying out melt blending on the modified bamboo fiber, poly (adipic acid) / butylene terephthalate, the modified polylactic acid and an auxiliary agent, and then carrying out extrusion granulation. The degradable bamboo fiber composite material master batch prepared by the invention has good processability and mechanical properties, and can be widely applied to the fields of disposable tableware, packaging materials, agricultural plastic mulching films and the like.

The invention relates to the technical field of compound fertilizers, and provides a slow-release compound fertilizer for corn and a preparation method of the slow-release compound fertilizer. The fertilizer is prepared from the following raw material components: 35 to 40 parts of thermoplastic resin coated urea, 400 to 450 parts of potassium chloride compound fertilizer, 200 to 300 parts of humic acid coated urea, 10 to 12 parts of zinc sulfate, 30 to 45 parts of large granular urea, 100 to 150 parts of microencapsulated bacillus subtilis granules and 10 to 15 parts of polylactic acid coated borax. According to the invention, borax is coated by a polylactic acid coating technology, so that the release speed of the boron element is effectively delayed, the boron element is ensured to be continuously released from the elongation stage of corn to the large bell mouth stage (20-30 days after sowing), and the problem of premature loss of the boron element in the prior art is solved.

The invention relates to the field of new materials, and discloses a method for preparing a composite material by filling PLA / PBS with fibers, and the composite material comprises the following raw materials by weight: 30-40 parts of polylactic acid, 10-20 parts of poly (butylene succinate), 40-50 parts of fibers, and 1-3 parts of maleic anhydride grafted polylactic acid. Comprising the following steps: S1, performing gradient modification on fibers: S101, pretreating the fibers by using a compound enzyme; s102, in a polylactic acid melt blending stage, adding maleic anhydride to carry out in-situ grafting compatibilization; s2, low-temperature high-shear dispersion: mixing the fibers modified in the step S1 with polylactic acid, poly (butylene succinate) and maleic anhydride grafted polylactic acid. Through a fiber gradient modification technology, bio-enzyme pretreatment and maleic anhydride in-situ grafting compatibilization are utilized, and an interpenetrating network structure of a polylactic acid chain segment is formed on the fiber surface, so that the tensile strength of the composite material is effectively improved to 80-90 MPa.

The invention relates to a polylactic acid test piece internal defect detection method, and belongs to the technical field of target detection, the method comprises the following steps: S1, image processing to obtain an input image; s2, attention enhancement feature extraction: preliminarily extracting spatial features, capturing global information and local information, focusing a defect area, and generating an enhancement feature map; s3, carrying out feature fusion, and outputting a fused feature map; s4, performing self-attention re-parameterization, and outputting a local feature map; s5, HSV spot detection including a color conversion algorithm and a defect enhancement algorithm; and S6, outputting a result, establishing a bounding box regression task, predicting a frame coordinate, outputting a defect position, identifying a category label, outputting a defect type, and evaluating reliability and outputting confidence. According to the method, feature extraction is carried out by using depth separable convolution, the visibility and detectability of low-contrast defects are enhanced, and the attention enhancement network is established to adaptively pay attention to key areas related to the defects, so that defect detection is more accurate and efficient.

The invention discloses preparation and application of an organic-inorganic interface layer modified zinc negative electrode. The preparation method comprises the following steps: firstly, dispersing organic polymer polylactic acid and zinc sulfide powder into tetrahydrofuran, then coating the surface of zinc foil with the dispersed solution, and drying a solvent at 70 DEG C, so as to prepare the zinc negative electrode modified by an organic-inorganic interface layer. According to the interface layer, zinc ion deposition is regulated and controlled, and the problem of zinc dendrite growth is solved. In addition, the polylactic acid-zinc sulfide composite coating can effectively improve the redox kinetics of zinc ions and improve the coulombic efficiency of the zinc negative electrode. Due to the good ionic conductivity, the interface modification layer can improve diffusion of zinc ions, and the polarization influence caused by the concentration gradient of the zinc ions is relieved. Therefore, the prepared polylactic acid-zinc sulfide composite interface layer modified zinc negative electrode symmetric battery has more excellent cycling stability, the half battery has more stable coulombic efficiency, and the assembled total battery has more prominent capacity retention rate.

The invention relates to a high-barrier antibacterial polylactic acid packaging material and a preparation method thereof, and belongs to the technical field of biodegradable packaging materials. The technical problems that a traditional polylactic acid material is insufficient in barrier property, poor in antibacterial performance and difficult to meet the packaging requirements of livestock and poultry meat, food and medicine are solved. A graphene oxide lamellar material is subjected to copper ion functionalization treatment and is bridged with tannic acid molecules through copper ions to form a nano filler, and then the filler is blended with a plasticized polylactic acid solution to prepare the membrane. The preparation method comprises the following steps: preparing a copper ion functionalized dispersion liquid from graphene oxide and copper nitrate, self-assembling the copper ion functionalized dispersion liquid and tannic acid under the condition that the pH is 8-10 to generate a nanofiller, uniformly dispersing the nanofiller, mixing the nanofiller with polylactic acid, polyethylene glycol and glycerol according to a specific mass ratio, coating to form a film, and controlling solvent volatilization conditions to obtain the high-performance packaging material. According to the method, the oxygen barrier property and the antibacterial activity of the material are remarkably improved through uniform dispersion of the nanofiller and reinforcement of a coordination network. The obtained material is suitable for packaging foods such as livestock and poultry meat.

The invention belongs to the technical field of catalyst preparation, focuses on a high-entropy alloy nanowire catalyst, and mainly relates to a preparation method and application of an AuCuAgPtNi catalyst. A one-pot wet chemical method is innovatively adopted, a 4-aminopyridine solvent and metal precursors of gold, copper, silver, platinum and nickel are fully and evenly mixed and placed in an oil bath pot at the temperature of 90 DEG C, then a reducing agent ascorbic acid is rapidly added, after specific reaction time, washing, drying and other operations are sequentially carried out, and the high-entropy alloy nanowire AuCuAgPtNi catalyst can be successfully prepared. The preparation method disclosed by the invention has the remarkable advantages of simple process, simple steps, convenience in operation and the like. In an alkaline environment, the prepared nanowire-shaped high-entropy alloy AuCuAgPtNi catalyst shows extremely excellent catalytic activity and selectivity for catalytic degradation of waste plastic polylactic acid, the waste plastic can be efficiently upgraded and converted into pyruvic acid, a new way is opened up for resource utilization of the waste plastic, and the application prospect is wide. The method has a wide application prospect in the fields of environmental protection and resource recovery.

The invention provides a high-hydrophobicity anti-pollution flashover coating and a preparation method thereof, and relates to the field of coatings. The silicone rubber composition is prepared from the following raw materials in parts by weight: 80 to 100 parts of hydroxyl-terminated polydimethylsiloxane; 5 to 15 parts of modified nano silicon dioxide; 10 to 30 parts of a composite self-repairing microcapsule; 10 to 25 parts of a flame retardant; 3-8 parts of a cross-linking agent; 0.5-2 parts of a catalyst; 1-5 parts of an accelerant; 40 to 100 parts of a solvent; the modified nano silicon dioxide is fumed silica subjected to surface treatment by a fluorine-containing silane coupling agent and a platinum catalyst; the capsule wall of the composite self-repairing microcapsule is a polylactic acid-glycolic acid copolymer, and the capsule core of the composite self-repairing microcapsule is a mixed solution of a hydroxyl-terminated polydimethylsiloxane oligomer and methyltris (methylethylketoximino) silane. The coating has excellent hydrophobicity, weather resistance and targeted repair function.

The invention discloses a high-barrier antibacterial packaging material, a preparation method thereof and a packaging bag, and belongs to the technical field of packaging, the packaging material comprises the following raw materials by weight: 75-85 parts of polylactic acid, 15-25 parts of poly (butylene succinate), 2-6 parts of epoxidized urushiol, and 1-3 parts of benzyl quaternary ammonium salt modified montmorillonite; the epoxidized urushiol is prepared by carrying out epoxidation reaction on urushiol and organic peroxy acid; the packaging material further comprises the following raw materials: 2-5 parts of sepiolite fiber loaded magnesium oxide; according to the invention, biodegradable polylactic acid and poly (butylene succinate) are taken as base materials, and epoxidized urushiol is taken as a reactive compatilizer, so that the compatibility between polylactic acid and poly (butylene succinate) is improved, and meanwhile, the binding property between a polymer matrix and benzyl quaternary ammonium salt modified montmorillonite and sepiolite loaded magnesium oxide is enhanced; the packaging material with good mechanical property, barrier property and antibacterial property is obtained.

The invention relates to the field of plastic bags, and discloses a biodegradable plastic bag and a preparation method thereof, the biodegradable plastic bag comprises polylactic acid, poly (butylene adipate-co-terephthalate), a functional additive, modified starch, a lubricant and an antioxidant; the functional additive is prepared by grafting hydroxylated modified castor oil and isocyanated montmorillonite loaded titanium dioxide; the hydroxylation modified castor oil is prepared by modifying castor oil with chloroethyl isocyanate, then reacting with N-allylimidazole, and then reacting with 6-mercaptohexyl-1-alcohol; the isocyanated montmorillonite loaded titanium dioxide is prepared by reacting montmorillonite loaded titanium dioxide obtained by a sol-gel method with isophorone diisocyanate; the modified starch is prepared by reacting octadecanoyl chloride and acryloyl chloride with starch, then carrying out graft copolymerization with ethyl acrylate and further introducing glycidyl methacrylate, so that the plastic bag is endowed with excellent mechanical properties, biodegradability and antibacterial property.

The present invention relates of a biodegradable and hydrophobic polylactic acid (PLA) non-woven material and a process for manufacturing thereof, said PLA non-woven material comprising a non-woven fabric for personal protective equipment, and a non-woven fabric for the three layer surgical mask; said PLA non-woven material comprising a layer of nanofiber membrane and a layer of biodegradable spunbond fabric which could fulfil the international biodegradation standard EN13432. Said non-woven fabric for the PPE has at least 45N breaking force, at least 15% elongation, and having passed level 3 fluid resistance test according to AATCC 42 and AATCC 127.

The invention relates to the technical field of thermoplastic vulcanizates, and discloses a TPV sealing material and a preparation method thereof. The TPV sealing material is prepared from the following raw materials in parts by weight: 10 to 30 parts of PP resin, 40 to 60 parts of EPDM rubber, 10 to 20 parts of polylactic acid, 15 to 25 parts of filler, 0.5 to 1.5 parts of vulcanizing agent, 0.3 to 1.5 parts of vulcanization accelerator, 5 to 10 parts of compatilizer, 1 to 4 parts of modified heat stabilizer and 0.5 to 3 parts of modified anti-aging agent. Through preparation of the modified heat stabilizer, structural damage or sealing failure caused by thermal aging of a system can be reduced, and the service life of the sealing material is greatly prolonged; the preparation of the modified anti-aging agent can effectively resist the corrosion of environmental factors such as thermal oxidation and ozone to the system, and prevent the problems of cracking, hardening, elasticity attenuation, sealing failure and the like of the sealing material after long-term use.

The invention relates to the technical field of dental restoration materials, in particular to a bacteriostatic dental restoration composite film and a preparation method thereof. The oral cavity restoration composite film is composed of an upper-layer antibacterial film, a middle-layer polycaprolactone fiber film and a lower-layer bone restoration film. The upper-layer antibacterial film is prepared from the following components in parts by weight: 3 to 4 parts of cinnamon essential oil, 0.5 to 1 part of xanthan gum, 0.5 to 1 part of seed meal protein, 0.1 to 0.15 part of tannic acid, 5 to 7 parts of silk fibroin, 1 to 1.5 parts of polylactic acid, 0.6 to 1 part of chitosan, 1 to 1.5 parts of polyvinyl alcohol and 1.5 to 2.5 parts of glycerol; the lower-layer bone repair membrane is prepared from the following raw materials in parts by weight: 2 to 3 parts of nano-hydroxyapatite, 3 to 5 parts of citric acid, 6 to 9 parts of lactic acid, 3 to 4 parts of tyrosine, 1 to 2 parts of glycollic acid, 2 to 3 parts of casein, 0.2 to 0.3 part of hyperoside and 1 to 2 parts of gelatin.

The invention discloses a yarn winding device for polylactic acid plant dyed yarn, and belongs to the technical field of yarn winding, the yarn winding device comprises a yarn winding main machine, a winding roller is rotatably connected to the yarn winding main machine, a layered yarn winding module is arranged on the outer side of the winding roller, and the layered yarn winding module comprises an inner net cylinder, a convex block, a hollow layered hole shell and a hollow abutting rod; according to the device, polylactic acid plant dyed yarn is guided by the two guide blocks and then wound on the outer side of the inner net cylinder, the two hollow layered hole shells transversely move back to the outer side of the inner net cylinder to replace the inner net cylinder to wind the yarn when conveying of the yarn is stopped, a layered yarn roll is formed, four protruding blocks are matched with four hollow abutting rods and supporting blocks, and the layered yarn roll is formed. The yarn is supported from multiple areas of the inner layer and the outer layer of each layer of yarn, the hollow abutting rod and the protruding block can guide and convey external specified gas into the hollow layered hole shell and the inner net cylinder, so that the contact exchange effect of the yarn in the inner area of the yarn roll and air is improved, and the rolled yarn collecting effect is improved.

The invention discloses a biodegradable polylactic acid composite material and a preparation method thereof, and relates to the technical field of polylactic acid materials. The method comprises the steps that firstly, chitosan activated through hydrochloric acid is subjected to graft modification through a KH550 silane coupling agent, meanwhile, nano-zinc oxide is subjected to surface modification through stearic acid, the chitosan and the nano-zinc oxide are mixed, spray drying is conducted, and antibacterial composite powder is prepared; the preparation method comprises the following steps: performing hydrochloric acid activation and KH570 silane coupling agent modification on nano silicon dioxide, performing hydroxypropylation modification on alkali lignin, and performing reflux crosslinking reaction on the modified alkali lignin, KH570 modified nano silicon dioxide, polycaprolactone, methyl methacrylate and azodiisobutyronitrile to prepare a heat-resistant reinforcer; uniformly mixing polylactic acid, poly (butylene succinate), the antibacterial composite powder, the heat-resistant reinforcer, tributyl citrate, polyethylene glycol and talcum powder, and extruding and granulating by using a twin-screw extruder to obtain the heat-resistant antibacterial material. The composite material prepared by the invention has excellent antibacterial property, heat resistance and biodegradability.

The present invention discloses a chitosan-modified highly transparent antibacterial polylactic acid film and a preparation method and application thereof. The polylactic acid film comprises the following raw materials by weight: 10 to 16 parts of modified chitosan, 35 to 55 parts of polylactic acid, 5 to 15 parts of casein, 50 to 300 parts of solvent and 30 to 50 parts of gelatin, wherein the solvent comprises hexafluoroisopropanol and acetic acid solution. The antibacterial polylactic acid film provided by the present invention has good toughness, strength and transparency, is suitable for the field of food packaging, can extend the shelf life of food, and can reduce plastic waste pollution.

The invention relates to the technical field of degradable materials, and discloses an environment-friendly degradable polylactic acid straw and a preparation process thereof. Comprising the following operation steps: step 1, adding chitosan into a mixed solution, uniformly mixing, adding an aminated lignocellulose-aqueous solution and a glutaraldehyde aqueous solution, uniformly mixing, adjusting the pH value to 6.5-7, reacting at 40-45 DEG C for 2.5-3 hours, washing and drying to obtain modified lignocellulose; step 2: (1) uniformly mixing modified polylactic acid, polyhydroxyalkanoate, modified wood fiber, tributyl citrate and triglyceride, banburying, discharging and crushing to obtain composite master batch; and (2) sequentially carrying out extrusion molding, cooling shaping and cutting on the composite master batch to obtain the degradable polylactic acid straw.

The invention relates to the technical field of food packaging materials, in particular to a cerium dioxide nano-enzyme modified antibacterial coating and application of the cerium dioxide nano-enzyme modified antibacterial coating in food packaging. The biomimetic mineralization layer comprises the following components in percentage by weight: 35-45% of a green base material, 8-12% of dopamine modified yttrium-doped cerium dioxide nano-enzyme, 4-6% of a composite antibacterial agent, 3-4% of a natural cross-linking agent, 2-3% of a degradable plasticizer, 1-2% of a biomimetic mineralization layer precursor and the balance of deionized water, the green base material is a blend of a chitosan-polyethylene glycol graft and polylactic acid; the doping amount of Y3 in the nano enzyme is 3-4at%. The antibacterial agent is excellent and lasting in antibacterial effect, has no migration risk of the antibacterial agent, and can guarantee food safety; a green base material and a degradable plasticizer are adopted, so that natural degradation is realized, and environmental pollution is avoided; the mechanical property is good, the aging resistance is realized, and the oxygen barrier property is strong; the food packaging box is suitable for various foods, effectively prolongs the shelf life, and meets the requirement of green packaging.

The invention discloses a riverway dredging method which comprises the following steps: dynamically scanning a riverway along a spiral propulsion path, and obtaining riverbed topographic data and sediment thickness in real time; a three-dimensional riverbed model is established based on the riverbed topographic data, and a core dredging area, a transition maintenance area and an ecological reserve area are divided in the three-dimensional riverbed model according to the sediment thickness; the core dredging area is divided into a surface layer, a middle layer and a bottom layer in the vertical direction, and a differentiated dredging process is executed; carrying out mud-water separation treatment on the dredged material, purifying the separated water, and reinjecting the purified water into the river channel; prefabricated ecological concrete modules are laid on the surface of a dredged riverbed, diversion trenches and biological nests are formed, and the biological nests are filled with polylactic acid / straw composite fiber felts containing local submerged plant seeds. Through spiral scanning, three-dimensional modeling and intelligent partitioning, integration of monitoring, planning, construction and repairing is achieved, accurate dredging is implemented, and the dredging efficiency is improved.

The invention discloses a tough full-bio-based polylactic acid / polyamide composite material and a preparation method thereof, and belongs to the technical field of polymer composite material preparation. The tough polylactic acid / polyamide composite material comprises polylactic acid, bio-based polyamide, a core-shell amide modified material, a hydrolysis stabilizer, an antioxidant and a chain extender. The core-shell amide modified material is prepared by filling a functional elastomer copolymer with amino nanoparticles. The core-shell amide modified material formed on the basis of the amino nanoparticle reactive filling functional elastomer copolymer has a micro core-shell structure formed in situ and a large number of amido bonds, so that the number of hydrogen bonds between molecular chains of a blend system is increased, and entanglement and intermolecular acting force between micro molecular chains of the blend material are improved; therefore, the system compatibility is improved, the absorption of the material on external stress and energy is enhanced, more obvious plastic deformation is generated when the material is stressed and deformed, and the material is endowed with better mechanical properties.