139 results about "Polycarbonic acid" patented technology

The invention discloses a grinding and polishing tool applied to curved surface machining and a preparation method of the grinding and polishing tool. The grinding and polishing tool comprises a grinding and polishing layer, a base body layer and a rigid layer. The grinding and polishing layer is a uniform mixture of hydrophilic resin and grinding materials, protrusions are evenly distributed, the center axes of the protrusions are perpendicular to the lower end face of the tool, and the spherical surface where the tops of the protrusions are located and the spherical surface where the bottoms are located are the same in radius and collinear in sphere center. The matrix layer is made of hydrophilic resin the same as that of the grinding and polishing layer; the rigid layer 3 is one of an organic glass plate, a polyvinyl chloride plate and a polycarbonate plate. A convex tool is adopted for concave surface machining, and a concave tool is adopted for convex surface machining. The grinding and polishing tool is integrally formed, bonding is reduced, functional structure integration of the tool is achieved, and the machining precision is improved; the hydrophilic resin has the swelling characteristic when encountering water, full flexibility of the tool is achieved, and the tool can be attached to the surface of a workpiece easily and has the self-finishing function.

The invention provides a method 100 for separating different polymeric spectacle lens materials in a mixture comprising at least two different polymeric spectacle lens materials by separating at least one polymeric spectacle lens material of the at least two different polymeric spectacle lens materials by using their different physical behavior and / or chemical behavior, wherein the at least two different polymeric spectacle lens materials are selected from the group consisting of polyallyl carbonate, polyurea, polyurethane, polyurethane / polyurea, polycarbonate, polyepisulfide and polythiourethane. The invention further provides a method for separating at least one polythiourethane from a mixture comprising at least two different polythiourethanes by thiolysis.

The invention belongs to the technical field of polyurethane resin, and provides polyurethane resin, polyurethane synthetic leather and a preparation method and application thereof. The preparation raw materials of the polyurethane resin comprise the following components in percentage by mass: 11%-18% of modified polyol, 3%-9% of bio-based polyol A, 0.01%-0.02% of an antioxidant, 0.001%-0.003% of a catalyst, 5%-7% of isocyanate, 0.5%-3% of a chain extender, 0.1%-0.4% of a terminator, 0.02%-0.04% of an anti-visbreaking aid, 0.5%-3% of a polyether aid and 68%-73% of a solvent, wherein the preparation raw materials of the modified polyol comprise bio-based polyol, alcohol amine and binary acid; the bio-based polyol A comprises bio-based polypropylene carbonate dihydric alcohol. The polyurethane synthetic leather prepared by the preparation method disclosed by the invention has good slip resistance, excellent perspiration-resistant color fastness and relatively high blackness, and is suitable for yoga mats.

The invention relates to the technical field of noise reduction core materials, in particular to a mesoporous ceramic / chlorinated polypropylene carbonate sound insulation foam core material and a preparation method thereof, and the mesoporous ceramic / chlorinated polypropylene carbonate sound insulation foam core material is prepared from the following raw materials in parts by mass: 3-20 parts of mesoporous ceramic, 75.6-92.6 parts of chlorinated polypropylene carbonate, 4 parts of azodicarbonamide and 0.4 part of zinc oxide. The mesoporous ceramic / chlorinated polypropylene carbonate foam material has the advantages of being low in density, high in strength, excellent in sound insulation performance, environmentally friendly and the like, the transmission loss at the intermediate frequency of 1000-2000 Hz can reach 34-60 dB, the compression modulus can reach 10.6-26.8 MPa, the compression strength can reach 0.24-0.45 MPa, and the mesoporous ceramic / chlorinated polypropylene carbonate foam material can serve as a sound insulation foam core material to be filled in a building wall and has the advantages of being good in sound insulation performance and the like. Good application prospects are realized in the fields of wall earthquake prevention and sound insulation in the building industry.

The invention belongs to the technical field of biodegradable high polymer materials, and particularly discloses a PLA / PPC degradable spinning material and a preparation method thereof. The PLA / PPC degradable spinning material is prepared from the following raw materials in parts by weight: 65 to 75 parts of terminated polypropylene carbonate, 15 to 20 parts of polylactic acid, 1 to 2 parts of epoxidized soybean oil, 7 to 10 parts of composite Na-montmorillonite, 3 to 5 parts of light calcium carbonate, 6 to 9 parts of rice straw fiber, 0.6 to 0.8 part of cross-linking agent, 0.2 to 0.5 part of antioxidant, 1 to 2 parts of maleic anhydride grafted PLA compatilizer, 0.07 to 0.01 part of catalyst and 0.3 to 0.5 part of silicone. Various raw materials are mixed, so that the mechanical property of the material is remarkably improved, the material has good strength and toughness, and the comprehensive performance of the material is improved.

Isocyanate-functional polyurethane prepolymers are prepared by reacting a polymeric diol, a non-linear short chain diol, a multifunctional polyol, and a diisocyanate. Coating compositions comprising the isocyanate-functional polyurethane prepolymers and a polyamine curing agent can be used to prepare topcoats that meet the demanding performance requirements of aerospace and other applications.

The invention relates to the technical field of modified polyurethane preparation, in particular to a modified rigid polyurethane foam material and a preparation method thereof.The material is specifically prepared from CO2-based polyol, polyether, deionized water, a foaming agent, a catalyst, a foam stabilizer and isocyanate. Wherein CO2-based polyol is introduced into original polyether polyol, specifically, poly (ethylene carbonate) polyol is added, so that the heat conductivity coefficient of the material can be reduced, the compression strength of the material can be improved, and the low-cost and high-performance polyurethane foam can be prepared. The finally prepared rigid polyurethane foam material has the characteristics of good heat insulation property and high pressure resistance; and the whole preparation process is simple, the whole cost is low, and the market competitiveness is high.

The invention provides a polyurethane composite material, a preparation method and application thereof and an intelligent fabric liner material, and belongs to the field of solid lubrication. The preparation method comprises the following steps: mixing polypropylene carbonate glycol, isophorone diisocyanate, 2, 2-dimethylolpropionic acid and a catalyst, carrying out a prepolymerization reaction, mixing the obtained prepolymer, 4, 4 '-diaminodiphenyl disulfide and 4, 6-diaminopyrimidine, carrying out a chain extension reaction, mixing the obtained chain extension product with triethylamine, and carrying out a polymerization reaction to obtain polyurethane resin; and mixing polyurethane resin, the isocyanate functionalized boron nitride nanosheets and the carbon quantum dots to obtain the polyurethane composite material. According to the invention, an advanced polyurethane composite material is constructed by innovatively combining self-repairing, wear resistance and damage monitoring functions for the first time, and the properties are realized by a design strategy of combining isocyanate functionalized boron nitride nanosheets and carbon quantum dots with multiple dynamic reversible bonds (disulfide bonds and hydrogen bonds).

The invention relates to a preparation method and application of a silicon-based biodegradable essence microcapsule, and the preparation method of the silicon-based biodegradable essence microcapsule comprises the following steps: S1, uniformly mixing oily essence and a silicon-based mesoporous material to obtain an oil phase; dissolving an emulsifier in water to obtain a water phase; s2, mixing the oil phase and the water phase, and homogenizing to obtain an emulsion; and S3, adding a diisocyanate compound and polypropylene carbonate into the emulsion, and carrying out a stirring reaction to obtain the silicon-based biodegradable essence microcapsule. A silicon-based mesoporous material is introduced in the process of preparing the essence microcapsule by taking polypropylene carbonate as a wall material, a synergistic wrapping system of the essence microcapsule is constructed, and the volatile essence is subjected to double-layer protection by utilizing a mode of combining physical adsorption and chemical crosslinking embedding, so that the fragrance retention time of the essence is prolonged, and the fragrance retention time of the essence is prolonged. Meanwhile, the embedding rate of the microcapsule can be effectively improved, and the application of the essence microcapsule in actual production can be promoted by combining the biodegradable characteristic of the polypropylene carbonate.

The invention relates to the technical field of polymer composite materials, in particular to a degradable PPC-based composite film as well as a preparation method and application thereof. The degradable PPC-based composite film is prepared from polypropylene carbonate, bamboo powder and vinyl trimethoxy silane. Polypropylene carbonate (PPC) is adopted as a base material, bamboo powder is combined for filling, the prepared composite film can be completely degraded after being buried in natural soil for 5 months, and degradation products of the composite film do not pollute the environment; the bamboo powder is adopted as a reinforcing filler, has a certain bacteriostatic effect, and can be used for delaying the growth of microorganisms on the surface of food and improving the food safety and the fresh-keeping effect if being applied to the food fresh-keeping film. Compared with a pure PPC film, the composite film disclosed by the invention is improved in the aspects of mechanical property, thermal stability and glass transition temperature, and shows more excellent comprehensive performance.

The invention relates to the technical field of lithium battery electrolyte, in particular to a composite enhanced solid electrolyte membrane and a preparation method thereof. The polymer solid electrolyte is a polycarbonate-based solid electrolyte such as a poly (ethylene carbonate)-based solid electrolyte PVC, a poly (vinylene carbonate)-based solid electrolyte PEC, a poly (propylene carbonate)-based solid electrolyte PPC, a poly (propylene carbonate)-based solid electrolyte PTMC and a polyoxyethylene-based solid electrolyte. The electrolyte is one or more of polysiloxane-based polymer electrolyte and single-lithium-ion conductive polymer electrolyte materials. The composite enhanced solid electrolyte membrane is disclosed. The preparation method comprises the following steps: preparing the three-dimensional nanofiber skeleton through electrostatic spinning, loading the two surfaces of mixed slurry of the polymer electrolyte and the lithium salt on the base membrane in an inert atmosphere, and carrying out vacuum curing molding. The composite membrane has high safety and a wide electrochemical window, the process of the composite membrane is compatible with an existing lithium battery production line, the raw material cost is controllable, and the composite membrane has large-scale commercial application potential.

The invention belongs to the technical field of degradable packaging materials, and discloses a preparation method of a degradable preservative film. The anti-fog antibacterial plastic is prepared from the following raw materials in parts by weight: 40 to 45 parts of poly (butylene adipate-co-terephthalate) (PBAT), 8 to 12 parts of polylactic acid (PLA), 28 to 32 parts of modified structural starch, 4 to 6 parts of poly (butylene carbonate) (PBC), 4 to 6 parts of talcum powder, 0.4 to 0.6 part of aluminate, 0.8 to 1.2 parts of a composite antibacterial agent and 2.5 to 3.5 parts of anti-fog master batch. The invention aims to overcome the defects in the prior art, and provides the degradable preservative film and the preparation method thereof, the preservative film not only has good degradability and mechanical properties, but also has excellent antibacterial and antifogging effects, and the preparation process is simple and easy for industrial production.

The invention relates to a polyethylene modified polycarbonate composite material, which is composed of the following components in parts by weight: 59 to 62 parts of polycarbonate A, 16 to 18 parts of polycarbonate B, 0.4 to 0.7 part of low density polyethylene, 20 to 23 parts of polysiloxane-polycarbonate random copolymer, and 0.1 to 0.4 part of antioxidant. The polycarbonate A is polycarbonate of which the solution flow rate is greater than 15g / (10min), and the polycarbonate B is polycarbonate of which the solution flow rate is less than 10g / (10min). The polyethylene modified polycarbonate composite material obtained by the invention is excellent in processability and simple in processing process, and the product has the advantages of stable quality, impact resistance, low temperature resistance, excellent heat resistance and the like.

The invention belongs to the field of modification of degradable fat polycarbonate materials, and particularly relates to a PCHC / PPC composite material and a preparation method thereof. A PCHC matrix material is added into PPC for blending modification, a PCHC / PPC blended matrix material is obtained, hydrophobic microcrystalline cellulose is further added, and the PCHC / PPC composite material is obtained. The invention aims to break through the limitation of an existing degradable material in specific application, the performance of a polypropylene carbonate PPC material is better improved through a layer-by-layer progressive optimization strategy, and a novel polycarbonate composite material is obtained, so that the thermal stability and the mechanical property of the material are improved, and wider application requirements are met.

The invention relates to the technical field of fracturing proppants, in particular to a method for preparing a low-density ceramsite sand fracturing proppant by taking magnesium oxide as a raw material, kaolinite coal gangue and solid waste ceramsite sand powder are adopted as main raw materials of inner core particles, magnesium oxide is introduced to reduce the density of the proppant, and the magnesium oxide acts with manganese oxide, potassium feldspar and dolomite to reduce the sintering temperature; the composite biomass-based porous activated carbon is used as a framework; the modified epoxy resin, the composite biomass-based porous activated carbon and the curing agent are used for preparing a self-repairing high-temperature-resistant, hydrophobic, wear-resistant and corrosion-resistant outer-layer coating film, so that the ceramsite sand fracturing propping agent is endowed with durable high flow conductivity; the self-repairing polyurethane is prepared by taking hydroxyl-terminated long alkyl chain Schiff base as a modifier in a prepolymerization process, taking polypropylene carbonate glycol, polytetrahydrofuran ether glycol and isophorone diisocyanate as raw materials, taking 2, 6-diaminopyridine as a chain extender and taking a carboxyl-containing imidazolyl hydrophobic copolymer as an end-capping reagent.

The invention relates to the field of high polymer material processing, and discloses a high-efficiency low-energy-consumption granulation process and system for a full-biodegradable multiphase composite material, and the process comprises the following steps: feeding raw materials such as polypropylene carbonate, polyester, plant fibers and four-stage activated biomass hydroxyapatite into a double-screw extruder with the length-diameter ratio of not less than 64: 1 in a grading manner according to heat sensitivity; the temperature, the pressure and the shear field are cooperatively controlled, and three-section type temperature distribution of intensified melting, short-time reaction and rapid cooling is established; and carrying out three-stage gradient vacuum devolatilization and underwater pelletizing to obtain a finished product. The four-stage activated biomass hydroxyapatite is prepared by plasma etching, hydrophobic coating, interface coupling and melt pre-dispersion. The problem of degradation of heat-sensitive components is solved through graded feeding and asymmetric temperature control, the dispersity and interface bonding force of the filler are improved by utilizing a four-stage activation technology, closed-loop control is realized by combining online rheology monitoring and an energy consumption model, and continuous production of the full-biodegradable material with low energy consumption, low volatile matter and high mechanical property is realized.

The invention provides a CO2 separation membrane with a high permeability coefficient and a preparation method and application thereof.The CO2 separation membrane is prepared from raw materials including polypropylene carbonate and polyadipic acid / butylene terephthalate, and by taking the total weight of the raw materials of the CO2 separation membrane as 100%, the content of polypropylene carbonate accounts for 70-95 wt%, the content of polyadipic acid accounts for 10-20 wt%, and the content of polyadipic acid accounts for 10-20 wt%. The content ratio of the polyadipic acid / butylene terephthalate is 4 to 30 percent. The CO2 permeability coefficient of the separation membrane can reach 35000 Bar (25 DEG C / 0.1 MPa) or above, the CO2 / N2 selectivity is 10-20, and the separation membrane is suitable for purification and separation of high-flow and low-concentration CO2.

The embodiment of the invention provides an electrolyte, a preparation method thereof, a battery, a preparation method of the battery, equipment and a device, which are used for solving the problem of poor cycle performance of a solid-state battery. The electrolyte comprises a first solid electrolyte layer, a transition layer and a second solid electrolyte layer, the transition layer is located between the first solid electrolyte layer and the second solid electrolyte layer, and the transition layer is formed by interpenetration of the first solid electrolyte layer and the second solid electrolyte layer. The first solid electrolyte layer comprises cross-linked vinylene carbonate and a first lithium salt; and the second solid electrolyte layer comprises a polycarbonate compound, an inorganic solid electrolyte and a second lithium salt. On one hand, the first solid electrolyte layer is not easily consumed due to side reaction with the positive electrode. And on the other hand, the first solid electrolyte layer and the second solid electrolyte layer can form an integrated composite solid electrolyte through the transition layer, so that the ion transmission rate of the composite solid electrolyte can be improved. And the cycle performance of the solid-state battery is improved.

The invention belongs to the technical field of coatings, and particularly relates to a water-based woodware varnish as well as a preparation method and application thereof. The water-based wood top-coat comprises a water-based emulsion, an organosilicon compound, a functional additive, a thickening agent, a wetting agent and water, the water-based emulsion comprises a self-crosslinking acrylic copolymer emulsion and an emulsion A; the emulsion A is selected from any one of self-crosslinking acrylic acid homopolymerized emulsion and polycarbonate modified polyurethane emulsion; the organosilicon compound comprises at least one of silane and silanol; the functional auxiliary agent comprises any one of a functional auxiliary agent 1 and a functional auxiliary agent 2; the functional additive 1 comprises a mildew preventive A and a mildew preventive B; the functional auxiliary agent 2 comprises a mildew preventive C, an ultraviolet light absorber and an ultraviolet light stabilizer; the thickeners include high shear, medium shear, and low shear polyurethane thickeners. The water-based woodware varnish disclosed by the invention has good comprehensive properties such as mildew resistance, weather resistance, chemical resistance and blocking resistance, and can be used for coating outdoor woodware or semi-outdoor woodware.

The invention discloses a method for upgrading polyester depolymerization to carboxylic acid ester and boric acid ester by catalyzing ionic liquid, which relates to the comprehensive utilization of waste resources and the cascade utilization of raw materials. The method uses multiple types of green ionic liquid catalysts to catalyze the methanolysis reaction of PET, and then phenylboronic acid captures the generated ethylene glycol in situ, and forms different types of five-membered cyclic boric acid esters through dehydration and cyclization. The products of the method of the invention are carboxylic acid ester and different five-membered cyclic boric acid esters. The invention can be used for the depolymerization and upgrading of waste PET materials, and can also be used for other similar polyesters and polycarbonates, such as polyethylene adipate, polyethylene succinate and polypropylene carbonate, which are also suitable for the recovery strategy of the invention, and the products are corresponding boric acid ester, dimethyl succinate and dimethyl adipate.

The invention discloses a UV (ultraviolet)-heat dual-curing waterborne polyurethane emulsion and a preparation method thereof. According to the UV-thermal dual-curing waterborne polyurethane emulsion, the heat resistance, the water resistance and the mechanical property of UV-WPUA can be improved, and meanwhile, the storage stability and the yellowing problem of the UV-WPUA can be improved; the polyurethane foam is prepared from the following components in parts by weight: 60-70 parts of binary isocyanate; 35 to 45 parts of polypropylene carbonate; 0 to 12 parts of 1, 4-butanediol; 50 to 55 parts of an acrylate monomer; 0.1 to 0.2 part of p-hydroxyanisole; 0 to 18 parts of sulfydryl silane; 0.1 to 0.3 part of an organic tin catalyst; 5-10 parts of a solvent; 100 to 150 parts of deionized water; belongs to the technical field of coatings.

The utility model discloses a burr removing device for processing a polycarbonate plate for a terrain vehicle, relates to the technical field of processing of the polycarbonate plate for the terrain vehicle, is suitable for removing edge burrs during processing of the polycarbonate plate for the terrain vehicle, and comprises a processing table, the transmission wheel is arranged in the processing table and is used for transmission; the limiting driving unit is arranged on the outer surface of the machining table and used for limiting; and the polishing unit is arranged at the top of the machining table and used for polishing. According to the device, the first hydraulic cylinder, the limiting sliding rod, the mounting plate, the fixing plate, the limiting wheel, the first driving motor, the driving wheel and the belt are matched with one another, so that the polycarbonate plate can be conveniently driven to move on the outer surface of the transmission wheel; and a fixing frame, a second driving motor, a lead screw, a limiting rod, a second hydraulic cylinder, a telescopic limiting rod, a mounting frame, a first polisher and a second polisher are matched with one another, so that the edge of the polycarbonate board can be conveniently polished, and the functionality of the removing device is improved.

The invention provides an adhesive and a preparation method of low-alloy ultrahigh-strength steel, and the adhesive comprises the following components in percentage by mass: 75-85% of polyformaldehyde, 5-11% of polypropylene carbonate, 2-5% of polylactic acid, 5-6% of stearic acid and 2-4% of ethylene-vinyl acetate copolymer. The optimized combination of the polypropylene carbonate and the polylactic acid in the adhesive has certain shape preserving performance, and can replace a skeleton component in a traditional plastic-based adhesive; the strength of the degreased brown blank can be guaranteed, the thermal decomposition temperature of framework components can be effectively reduced, introduction of impurity elements C and O of a metal matrix is reduced, and the comprehensive mechanical property of a sintered product can be improved. In addition, main decomposition products of polypropylene carbonate are carbon dioxide and cyclic propylene carbonate, and thermal decomposition products of polylactic acid are lactic acid, ethanol, carbon dioxide and water. Polypropylene carbonate and polylactic acid are used as raw materials, thermal decomposition products of polypropylene carbonate and polylactic acid are environment-friendly and are green and environment-friendly materials, polypropylene carbonate and polylactic acid are low in price, the degreasing process is simple, convenient and high in efficiency, and the cost of metal powder injection production can be reduced.

To provide a polymer solid electrolyte having excellent heat resistance and electrochemical stability, a method for manufacturing the polymer solid electrolyte, and a lithium ion secondary battery including the polymer solid electrolyte.SOLUTION: A polymer solid electrolyte includes a polyethylene carbonate derivative represented by the following chemical formula (1), an inorganic filler, and a lithium salt. (R may have a substituent and is an acetyl group, a propionyl group, or a phenyl group; n is 100 or more.)SELECTED DRAWING: None

The invention relates to the technical field of sound insulation and noise reduction foam, in particular to a mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microporous foam material and a preparation method thereof, and the foam material is prepared from the following raw materials in parts by mass: 2-20 parts of mesoporous ceramic and 80-98 parts of chlorinated polypropylene carbonate. The mesoporous ceramic / chlorinated polypropylene carbonate foam material has the advantages of being high in strength, low in density, excellent in sound insulation performance, environmentally friendly and the like, the average transmission loss at the medium-high frequency of 1000-6300 Hz can reach 46-51 dB, the compression modulus can reach 38-48 MPa, the compression strength can reach 2.6-3.7 MPa, and the mesoporous ceramic / chlorinated polypropylene carbonate foam material is an excellent novel light sound insulation foam material and has good application prospects. The method can be applied to the fields of rail transit, recording studios, building walls and the like.

The application discloses a kind of Janus nanoparticles, its preparation method includes the following steps: (1) polypropylene carbonate diol (PPCD) is reacted with lysine diisocyanate, after reaction, TiO2 Hollow sphere dispersion is added in system, and TiO2 Hollow sphere of outer surface grafting PPCD is prepared;(2) after ultrasonic fragmentation, TiO2-PPCD nanoparticle is obtained, and then is reacted with silane coupling agent, poly-D-lactic acid (PDLA), and the Janus nanoparticle is prepared.The application is used to prepare biobased polyester composition, including the following weight parts of raw materials: polypropylene carbonate 60-90 parts, poly-D-lactic acid 10-40 parts, Janus nanoparticle 0.1-3 parts.The nanoparticle of the application effectively improves the compatibilization efficiency of the composition, and the tensile strength and elongation at break are also improved.

The invention discloses a method for preparing a polyurethane hot melt adhesive for wood edge banding, and belongs to the technical field of hot melt adhesives. The preparation method comprises the following steps: (1) mixing isocyanate and polyol, adding a catalyst, and stirring and reacting at 70-85°C for 20-30 minutes; (2) adding polypropylene carbonate, nanocomposite microcapsules, modified nano mineral crystals, modified mineral wool, and a tackifier to the solution of step (1), mixing at 100-130°C for 2-3 hours, and obtaining a polyurethane hot melt adhesive. The polyurethane hot melt adhesive prepared by the method of the invention has fast curing speed, good bonding performance, high aging resistance, and low release of harmful gases during use.

The present application relates to the field of film, specifically to a kind of high-temperature-resistant thermal medical film with stable imaging and its preparation process, introduce alumina phase in silica aerogel, modify silica aerogel doped with alumina phase with amino hetero naphthalene diphenyl poly aryl ether ketone;In order to give back layer, protective layer excellent mechanical damage resistance, make it after suffering mechanical scratch, self-repair at room temperature, restore excellent hydrophobicity, high temperature resistance, antistatic property, introduce self-repairing polyurethane in back layer and protective layer, with polypropylene carbonate glycol as soft segment, with isophorone diisocyanate as hard segment, 4,4'-dithiodiphenylamine, 4-hydroxyphenylboric acid as chain extender to synthesize self-repairing polyurethane;Epoxy silicone resin is used as the base coating of back layer and protective layer, introduce silicone slip agent in back layer, so that back layer has long-acting stable and non-migratory slip property.

The invention discloses a porous corn straw degradable film and a preparation method thereof, and belongs to the technical field of plastic films. The film is prepared from the following raw materials in parts by weight: 85-87 parts of polyadipic acid / butylene terephthalate (PBAT), 1-3 parts of polylactic acid (PLA), 5-10 parts of corn straw powder, 3-5 parts of polypropylene carbonate (PPC), 5-10 parts of starch, 3-5 parts of talcum powder and 1-3 parts of sodium bicarbonate. The preparation method comprises the following steps: drying and mixing the raw materials, carrying out melt blending in a double-screw internal mixer, carrying out granulation, and carrying out blow molding on the obtained master batch to prepare the film. The preparation method is characterized in that sodium bicarbonate is decomposed to release carbon dioxide gas during film blowing and heating, a uniform microporous structure is formed in a film matrix, and the decomposed product sodium carbonate plays a reinforcing role at the same time. The corn straw, the PPC, the starch and the talcum powder are added to generate a synergistic effect with a PBAT / PLA matrix, so that the mechanical property, the barrier property and the ultraviolet shielding function of the film are remarkably improved on the premise of ensuring complete biodegradability. The film has the advantages of being low in cost, uniform in pore structure, good in mechanical property, low in water vapor permeability, good in heat preservation effect and the like, and is an environment-friendly agricultural mulching film material with great application potential.

The invention relates to the field of high polymer materials, and particularly discloses a biodegradable composite express packaging bag and a preparation method thereof. A biodegradable composite express packaging bag comprises an outer layer film, a fiber layer, a framework layer, a fiber layer and an inner layer film. The outer layer film and the inner layer film are PBAT blended films, and the PBAT blended films are prepared from the following raw materials in parts by weight: 5 to 6 parts of PBAT resin, 1 to 1.5 parts of polyglycolic acid, 3 to 4 parts of polypropylene carbonate, 0.05 to 0.1 part of compatilizer, 0.15 to 0.2 part of antioxidant and 0.1 to 0.15 part of lubricant; the raw materials of the fiber layer comprise PBAT resin, PBST resin and a compatibilizer, and the fiber layer is prepared through melt differential electrostatic spinning; and the framework layer is an aramid nanofiber layer loaded with MOF-808. The biodegradable composite express packaging bag has the advantages of being high in longitudinal and transverse tensile strength, high in tear resistance, suitable for express packaging, capable of being biodegraded and excellent in barrier property.