84results about How to "Improve melt strength" patented technology

The invention belongs to the field of polymeric membranes. The invention relates to a BOPLA (biaxially-oriented polylactic acid) film with high stretching ratio and a preparation method thereof. The packaging film comprises the following raw materials in parts by weight: 80-90 parts of PLA; 10 to 20 parts of PPC-P (Polypropylene Chloride-P); 10-15 parts of a plasticizer; 3.0 to 5.0 parts of a chain extender; 0.3 to 0.5 part of an antioxidant; 0.5 to 1.0 part of a lubricant; 0.1 to 0.3 part of an anti-hydrolysis agent; wherein the total mass of the PLA and the PPC-P is 100 parts; the preparation method comprises the following steps: mixing, extruding and plasticizing the raw materials according to the formula, and carrying out an asynchronous two-way stretching process, heat setting, traction, slitting and rolling. According to the present invention, the defects of mechanical property degradation and poor optical property of the PLA under the high stretching rate in the prior art can be effectively solved, and the great application potential is provided.

The invention belongs to the technical field of high polymer materials, and particularly discloses a cross-linked antistatic supercritical microcellular foaming material. Comprising the following raw materials in parts by weight: 80-100 parts of HIPS, 10-15 parts of thermoplastic elastomer, 5-10 parts of low-density polyethylene, 10-15 parts of organic multifunctional master batch, 5-10 parts of high-dispersion conductive functional filler, 5-10 parts of modified calcium sulfate whisker, 5-10 parts of grafted modified talcum powder master batch, 1-5 parts of cross-linking agent, 1-5 parts of lubricant and 1-5 parts of antioxidant. The invention provides a cross-linked antistatic supercritical microcellular foaming material as well as a preparation method and application thereof. The cross-linked antistatic HIPS supercritical microcellular foaming material which is excellent in comprehensive performance and can be applied to multiple fields is prepared.

The invention relates to a preparation method of a supercritical foaming polylactic acid material, and belongs to the technical field of foaming polylactic acid.The preparation method comprises the steps that a polycaprolactone-polylactic acid copolymer and a chain extender YMX-06 serve as modifiers to prepare modified polylactic acid granules, so that the strength and ductility of polylactic acid melt are improved, and the foaming temperature and pressure are reduced; in a supercritical state, carbon dioxide has high diffusivity and low viscosity, so that the carbon dioxide can uniformly permeate into a modified polylactic acid granule matrix to form tiny bubbles, the bubbles are not easy to collapse in a bubble growth stage, the pore size distribution uniformity is good, the sizes of the bubbles are small, and the walls are thin; compared with pure polylactic acid, the obtained modified foaming material is higher in foaming ratio, lighter, better in heat retaining property and high in mechanical strength. The ultralight, environment-friendly and foaming agent residue-free degradable foam material can be used in the fields of building insulation, cold-chain transportation, anti-collision packaging and the like.

The invention relates to the field of novel polymer materials, and particularly discloses a degradable expandable polylactic acid polymer foam material and a preparation method thereof, the degradable expandable polylactic acid polymer foam material comprises the following raw materials: a polylactic acid-starch-polyamide blending modified mixture, polylactic acid foam material waste leftover materials, a foaming agent, a nucleating agent and an activating agent; the preparation method comprises the following steps: melting and mixing polylactic acid, acylated starch and polyamide in proportion to prepare a polylactic acid-starch-polyamide blending modified mixture, weighing the polylactic acid-starch-polyamide blending modified mixture, mixing the polylactic acid-starch-polyamide blending modified mixture with the polylactic acid foaming material waste leftover materials, the foaming agent, the nucleating agent and the activating agent, and performing extrusion molding to obtain the polylactic acid foaming material. Extruding and pelletizing to obtain foaming master batch, and foaming and forming; the preparation method has the characteristics that the expandable performance of the polylactic acid material is improved, and the prepared polylactic acid foam material is more uniform in cell size distribution, small in cell size and excellent in mechanical property.

The invention discloses a method for preparing high-melt-strength polypropylene by using a bifunctional acrylate monomer, and relates to a method for preparing the high-melt-strength polypropylene by using bifunctional acrylate as a monomer long-chain branched modified polypropylene. The invention aims to solve the problem that the application capability of polypropylene is influenced due to low strength of polypropylene melt. The method comprises the following steps: 1, adding polypropylene particles, a bifunctional acrylate monomer, an interface agent, a co-monomer, an initiator and deionized water into a reactor, and heating for swelling; 2, heating the reaction system, and carrying out a grafting reaction; and 3, washing, extracting and drying the grafted product to obtain the bifunctional acrylate modified high-melt-strength polypropylene. The grafting effect of the high-melt-strength polypropylene is regulated and controlled by regulating and controlling the preparation process, so that the melt strength of the polypropylene is improved, and the application performance of the polypropylene is further improved. The method is applied to the technical field of polymer materials.

The invention provides a low-odor ratproof extrusion-grade polypropylene material, a preparation method and an electrical material, and belongs to the field of polypropylene materials. The polypropylene is used as a main body, the flexibilizer is used for modifying the polypropylene, the used flexibilizer is linear low-density polyethylene and polyolefin elastomer, the melt strength of the flexibilizer is higher, the flexibilizer and the polypropylene are all olefins and have good compatibility, the price of the low-density polyethylene is lower, and the price of the polyolefin elastomer is higher, so that the low-density polyethylene, the polyolefin elastomer and the low-density polyethylene are combined, and the polypropylene is modified. According to the low-odor rat-proof extrusion-grade polypropylene material, the impact resistance of the polypropylene material is enhanced while the production cost is guaranteed, meanwhile, in order to improve the flame retardance of the low-odor rat-proof extrusion-grade polypropylene material, the flame retardant and the mineral substances are added, and the rat-proof agent is further added to prevent the material from being bitten by rats and insects and causing damage to the material; in addition, a special thread element is used in the double-screw extruder, so that the feeding amount is increased, the shearing heat is reduced, the melt temperature is reduced, and the odor grade of the material is reduced.

The invention discloses a flame-retardant antistatic rubber material for a conveying belt and a preparation method of the flame-retardant antistatic rubber material, and relates to the technical field of rubber materials. The rubber material is prepared from the following components: 40-80 parts of chloroprene rubber, 10-40 parts of butadiene rubber, 10-30 parts of high styrene rubber, 20-40 parts of a reinforcing agent, 15-30 parts of an antistatic agent, 10-30 parts of aluminum hydroxide, 10-20 parts of a modified flame retardant, 5-10 parts of polyethylene fibers, 5-10 parts of zinc stearate, 3-6 parts of a coupling agent, 4-8 parts of a vulcanizing agent, 1-3 parts of an accelerant and 1-3 parts of an anti-aging agent. Basic performance is provided through a compounding system of three kinds of rubber, the mechanical performance is improved by adopting an attapulgite-carbon black compounding reinforcing system, and the antistatic and flame-retardant functions are achieved in combination with the antistatic agent and the specially-made modified flame retardant.

The invention discloses a preparation method of polylactic acid fibers for medical and sanitary materials, and relates to the technical field of polylactic acid fibers. Nano-crystalline cellulose, nano-graphite particles and polylactic acid are blended and crosslinked, the mechanical property of a matrix is enhanced, the antibacterial property is achieved, fibers are prepared through spinning, supercritical carbon dioxide treatment is conducted for the first time, the nano-graphite particles can play a role of a nucleating agent, polylactic acid is promoted to form fine and uniform crystals, and the mechanical property of the matrix is improved. Carbon dioxide is effectively wrapped in the foaming process, a micropore structure is formed in the fiber, the mechanical property of a matrix is enhanced, then secondary supercritical carbon dioxide treatment is conducted, the nano-silver is loaded into the matrix through supercritical fluid, the antibacterial property and the mechanical property are further improved, then the nano-silver is soaked in a silicate solution, dehydration is conducted, and the nano-silver fiber is obtained. A silica gel layer is formed on the surface of the fiber, so that the mechanical property and the antibacterial property of a matrix are enhanced.

The invention provides branched polylactic acid as well as a preparation method and application thereof. The branched polylactic acid is prepared from the following raw materials: lactide and an initiator, the initiator comprises a first initiator, and the molecular structure of the first initiator contains a hydroxyl group and an epoxy group. The branched polylactic acid adopts a compound containing hydroxyl and epoxy as an initiator, so that the branched polylactic acid has the advantages of high melt strength, good flowability, easiness in processing, low cost and simple preparation method.

The invention relates to the technical field of high polymer material processing, in particular to a supercritical thermoplastic elastomer foaming sheet and a preparation method thereof, and is characterized in that the supercritical thermoplastic elastomer foaming sheet is prepared from the following raw materials in parts by weight: 90-100 parts of thermoplastic polyurethane (TPU) and / or thermoplastic polyester elastomer (TPEE) and / or block polyether amide elastomer (PEBAX), 0.1-1 part of chain extender, 0.1-3 parts of nucleating agent and 0.1-0.5 part of antioxidant, 0.1 to 3.5 parts of an antistatic agent; by optimizing the material formula and the cooling and mold opening technology, the technical problems existing in the production process of the thermoplastic elastomer foamed sheet in the prior art are solved, and a high-performance and multifunctional novel material solution is provided for multiple fields of automobiles, sports equipment, medical equipment and the like.

The invention discloses a nylon elastomer composition as well as a preparation method and application thereof. The composition comprises the following components: 100 parts of nylon elastomer; 20 to 100 parts of a polyolefin elastomer; 1 to 10 parts of an amphiphilic branched copolymer; 0.1 to 0.5 part of an antioxidant and 0.1 to 0.5 part of a lubricant. The composition disclosed by the invention is good in overall compatibility and high in elongation at break and melt strength.

The invention discloses a low-cost high-performance full-biodegradable polylactic acid-based heat-shrinkable film which is prepared from the following raw materials in parts by weight: 10-30 parts of polylactic resin, 70-90 parts of poly (butylene adipate-co-terephthalate) resin, 0.5-5 parts of a chain extension compatibilizer, 0.1-1 part of an antioxidant, 1-3 parts of a lubricant, 5-30 parts of a modified inorganic filler and 1-5 parts of an ultraviolet radiation aid, the invention also discloses a preparation method of the thermal shrinkage film. According to the thermal shrinkage film, the plastic component can be completely biodegraded in the natural environment, serious white pollution caused by the fact that the plastic is discarded into the natural environment is avoided, meanwhile, the lactide raw material part for synthesizing the PLA resin comes from grain processing by-products, and value-added utilization of the grain processing by-products is facilitated.

The invention discloses a polyhydroxyalkanoate composition and a preparation method thereof. The polyhydroxyalkanoate composition comprises the following components in parts by mass: 100 parts of polyhydroxyalkanoate; 0.5 to 5 parts of unsaturated D-polylactic acid; 0.5 to 5 parts of poly (L-lactic acid); the preparation method comprises the following steps: S1, carrying out melt blending on the polyhydroxyalkanoate and the unsaturated D-polylactic acid, and enabling the polyhydroxyalkanoate and the unsaturated D-polylactic acid to fully react, so as to obtain an intermediate product; and S2, carrying out melt blending on the intermediate product obtained in the step S1, poly-L-lactic acid and an ester exchange inhibitor to finally obtain the polyhydroxyalkanoate composition with excellent thermal stability, high melt strength and high crystallization speed.

The invention relates to the technical field of polymer composite material preparation, in particular to a super-tough core-shell stereocomplex polylactic acid-based composite material and a preparation method thereof. The super-tough core-shell stereocomplex polylactic acid-based composite material is prepared from the following raw materials in parts by mass: 70 to 100 parts of polylactic acid and 0 to 30 parts of the modified elastomer in claim 4, and the dosage of the modified elastomer is not 0; the modified elastomer is prepared by melting and blending stereocomplex polylactic acid powder and a functional elastomer copolymer; the stereocomplex polylactic acid powder is prepared by reactive melt blending of PLLA and PDLA in an equal mass ratio or an equal molar ratio. The prepared super-tough core-shell stereocomplex polylactic acid-based composite material has excellent tensile strength and impact resistance, can be applied to the field of engineering plastics such as automobile parts, electronic and electric appliance shells, household products, catering tableware and the like, and has remarkable environmental protection benefits and industrial popularization value.

This invention discloses a method for preparing low-density, high-filler SPC flooring. The method is characterized by a raw material formulation comprising the following components in the indicated weight proportions: 100 parts graft-modified PVC resin, 300-350 parts filler, 9-12 parts heat stabilizer, 3-5 parts melt processing modifier, 3-5 parts reinforcing and toughening modifier, 1-2 parts external lubricant, 1-2 parts internal lubricant, 2-5 parts chemical foaming agent, and 2-5 parts foaming aid. The graft-modified PVC resin is prepared by replacing the chlorine atoms in PVC with p-aminothiophenol, followed by an amidation reaction between a diacid or polyacid and an amino group. Its advantages are: 1) It improves the melt strength and expandability of the PVC resin, ensuring foaming performance under high filler content. Compared with ordinary SPC flooring, the flooring product has lower density and lighter weight, higher hardness, and lower overall formulation cost compared to ordinary low-density SPC flooring. 2) The process is simple, and the product has high controllability.

The present invention discloses a polyamide foam material and a preparation method thereof, and relates to the technical field of buffer protection, in order to solve the problem of poor resilience and compressive strength of polyamide foam materials. A polyamide composite material is subjected to a cross-linking reaction to obtain a polyamide material to be foamed, wherein the polyamide composite material includes a composite material formed by a polyethylene resin and polyamide; the polyamide material to be foamed is subjected to two-stage foaming by a supercritical foaming method to obtain a polyamide foam material. The polyamide foam material and the preparation method thereof are used to improve the resilience and compressive strength of the polyamide foam material.

This invention relates to the field of polymer foaming materials technology, and discloses a plant fiber composite nucleating agent for microfoaming of biodegradable materials and its application. The plant fiber composite nucleating agent is made from raw materials comprising the following parts by weight: 80-95 parts of primary ultrafine plant fiber powder, 5-20 parts of surface modifier, and 0.1-5 parts of dispersing lubricating wax; the surface modifier and dispersing lubricating wax are coated on the surface of the primary ultrafine plant fiber powder. The application steps are as follows: adding the plant fiber composite nucleating agent to a biodegradable material matrix to obtain a pre-foaming blend, introducing foaming gas or adding a chemical foaming agent for foaming treatment. The nucleating agent of this invention improves the compatibility between plant fibers and hydrophobic biodegradable matrices, provides heterogeneous nucleation sites in the matrix while increasing the polymer melt strength, inhibits cell coalescence and rupture, and obtains microfoamed materials with uniform pore size. Furthermore, the nucleating agent itself is completely biodegradable.

The invention belongs to the technical field of high polymer materials, and discloses an ion-modified polypropylene resin composition with wide molecular weight distribution and a preparation method thereof, the resin composition contains polypropylene with wide molecular weight distribution, organic acid / anhydride, organic metal salt and a functional auxiliary agent; based on 100 parts by weight of the polypropylene with wide molecular weight distribution, the content of the organic acid / acid anhydride is 0.1-3 parts by weight, the content of the organic metal salt is 0.1-2 parts by weight, and the content of the functional additive is 0.01-1 part by weight. According to the ion-modified polypropylene resin composition with wide molecular weight distribution, the melt strength is improved while the viscosity is reduced, and the application of the ion-modified polypropylene resin composition in high resin sag resistance processing technologies such as foaming, film blowing and hollowing is facilitated.

The invention provides an environment-friendly high polymer material additive as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials, the preparation method comprises the following steps: dissolving beta-cyclodextrin into an anhydrous solvent, adding methacryloyl chloride, controlling the molar ratio of methacryloyl chloride to beta-cyclodextrin to be 1: 1, carrying out substitution reaction, then adding excessive acetic anhydride, and carrying out heat preservation reaction to obtain the environment-friendly high polymer material additive. Carrying out acetylation reaction, and purifying to obtain modified beta-cyclodextrin; adding glycidyl methacrylate, ethylene and modified beta-cyclodextrin into a reaction kettle, and carrying out high-pressure free radical polymerization in the presence of an initiator and a chain transfer agent to obtain the environment-friendly high polymer material additive, wherein the mass ratio of the glycidyl methacrylate to the ethylene to the modified beta-cyclodextrin is (4-8): (88-94): (2-4). According to the prepared additive, the processing rheological property and mechanical toughness of a PCR material are improved, meanwhile, the release characteristic of low-volatility organic compounds is considered, and the application requirements of the fields of automobile interiors and high-end packaging are easily met.

The invention relates to a fluoride-free flame-retardant polyester reinforced resin composition as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The resin composition comprises the following components in parts by weight: 15-55 parts of PBT resin; 0 to 20 parts of PET resin; 10 to 50 parts of glass fiber; 10 to 15 parts of brominated aromatic flame retardant; 1-3 parts of a compatilizer; 1-5 parts of a toughening agent; 1.5 to 3.0 parts of an antimony flame retardant synergist; 2-5 parts of a high carbon residue charring agent; 0.2 to 0.5 part of an antioxidant; and 0.5 to 1.0 part of a lubricant. Compared with the prior art, the fluorine-free flame-retardant polyester reinforced resin prepared by the invention not only has excellent mechanical properties and good processability, but also has lower cost and wide application scenarios.

The application discloses a kind of polylactic acid double-stretching film materials and preparation method thereof, belong to the field of biaxially oriented film.The polylactic acid double-stretching film material includes the following mass fraction of raw materials: polylactic acid 95~99 parts, melt strength improvement aid 1~5 parts, hydrolysis inhibitor 0.3~1 parts and processing aid 0.5~1 parts;Melt strength improvement aid is ultra-high molecular weight polar polymer;Ultra-high molecular weight polar polymer contains one or a combination of two of epoxy group and side chain ester group.The melt strength improvement aid improves the melt strength and melt uniformity of polylactic acid, thereby improving the yield and film thickness uniformity of polylactic acid double-stretching film;The addition of hydrolysis inhibitor improves the heat processing stability of the material, to obtain a kind of processing performance excellent, while taking into account melt strength and uniformity, thickness fluctuation small polylactic acid double-stretching film material.

This invention discloses a method for preparing a modified chitosan whisker-reinforced and toughened PBAT microfoamed composite material. Biodegradable and high-modulus chitosan whiskers are selected as the reinforcing agent, enabling the composite material to achieve full biodegradability. Through surface modification technology, PBAT segments with the same composition as the PBAT matrix are introduced onto the surface of the chitosan whiskers. This design ensures good compatibility between the chitosan whiskers and the matrix, resulting in thorough dispersion within the matrix and achieving a more efficient reinforcement and toughening effect than traditional reinforcing agents. Simultaneously, the grafted and modified chitosan whiskers can increase the melt viscosity and melt strength of the PBAT matrix, thereby improving its foaming properties.

This invention relates to the field of propylene polymerization, and discloses a polypropylene, its preparation method, and its applications. The polypropylene has a molecular weight distribution of 6-20; at 230℃, a melt index of 0.1-10 g / 10 min with a loading of 2.16 kg; an isotactic index ≥97%; a fraction with a weight-average molecular weight M ≥ 5 million g / mol containing ≥1 wt%, a fraction with 1000 g / mol < M < 50000 g / mol containing 5-30 wt%, a fraction with 50000 g / mol ≤ M < 5 million g / mol containing 60-90 wt%, and a fraction with M ≤ 1000 g / mol containing <1 wt%; a melt strength ≥0.4 N at 230℃; a heat distortion temperature ≥95℃; and a flexural modulus ≥1800 MPa. This polypropylene exhibits high isotacticity, a wide molecular weight distribution, high flexural modulus, and also high melt strength and heat resistance.

The invention discloses a preparation method and application of high-melt-strength polypropylene, and relates to the technical field of high polymer materials. The invention aims to solve the problem of low melt strength of polypropylene prepared by the traditional process. The method comprises the following steps: S1, adding polypropylene, a difurfuryl sulfide monomer, an interface agent, a co-monomer, a main antioxidant, an auxiliary antioxidant, an initiator and deionized water into a reaction kettle, carrying out a full swelling reaction, heating to 80-95 DEG C, and carrying out a grafting reaction at 80-95 DEG C for 0.5-8 h; and S2, firstly soaking the grafted product by using a solvent, then extracting by using an organic solvent, and finally drying to obtain the high-melt-strength polypropylene. The invention can obtain the preparation method and the application of the high-melt-strength polypropylene.

The invention relates to a grain fiber-PVC (polyvinyl chloride) composite foamed sheet with a surface co-extrusion layer and a preparation method of the grain fiber-PVC composite foamed sheet. Comprising a middle foaming layer and a surface co-extrusion layer, and the middle foaming layer and the surface co-extrusion layer both comprise PVC resin and rice hull powder. The rare earth composite stabilizer is added, so that the environment-friendly function is achieved, the rare earth stabilizer further has the coupling, reinforcing and brightening functions in the PVC material, and in addition, the rare earth composite stabilizer can further adjust the decomposition temperature of the foaming agent and achieve the effects of toughening and capacity increasing; the foaming agent is prepared by compounding an AC foaming agent and an NC foaming agent, so that the extrusion rate can be increased, meanwhile, the dimensional deviation of the product is reduced, and the surface hardness can reach about Shore D hardness 80; the weight ratio of the rare earth compound stabilizer to the foaming agent to the foaming regulator is (1-5): (0.5-1.6): (3-9). Plasticization in the processing process can be promoted, and meanwhile, the mechanical property of the material is improved.

The invention relates to the technical field of polypropylene composite boards, in particular to a high-strength polypropylene hollow plastic board and a preparation method thereof.The preparation method comprises the following processes that polypropylene, maleic anhydride grafted polypropylene, filler, epoxy resin, a curing agent and auxiliaries are mixed, extruded, drawn and subjected to board pulling forming, and a panel and a core layer are formed respectively; and compounding the panel and the core layer to obtain the polypropylene hollow plastic plate. The polypropylene hollow plastic plate is formed by the panels and the core layer with the hollow structure, so that good mechanical properties are obtained. The branched epoxy resin and the bisphenol A epoxy resin are compounded and added into a material system of the polypropylene hollow plastic plate, so that entanglement and crosslinking among system molecules are increased, the melt strength is enhanced, and the mechanical property, heat resistance, ultraviolet resistance and the like of the prepared polypropylene hollow plastic plate are improved.

The invention discloses a high-melt-strength ethylene-tetrafluoroethylene copolymer and a preparation method thereof, and the preparation method comprises the following steps: preparing the ethylene-tetrafluoroethylene copolymer by adopting an emulsion polymerization mode, and introducing a reaction type functional group into an ethylene-tetrafluoroethylene copolymer molecular chain through a polymerization process to obtain the high-melt-strength ethylene-tetrafluoroethylene copolymer. The ethylene-tetrafluoroethylene copolymer containing the reaction type functional group is obtained; and carrying out a micro-crosslinking reaction on the ethylene-tetrafluoroethylene copolymer containing the reactive functional group and a micro-crosslinking assistant containing more than three degrees of functionality under the action of a catalyst to obtain the ethylene-tetrafluoroethylene copolymer with high melt strength. A reaction type functional group is introduced in the polymerization process, the high-melt-strength ETFE copolymer with a high molecular weight and a long branch chain structure is obtained in a micro-crosslinking reaction mode, the good heat resistance and mechanical performance of a linear ETFE copolymer are considered, meanwhile, the high-melt-strength ETFE copolymer has higher melt strength and higher critical shear rate, processing is more stable, and the high-melt-strength ETFE copolymer is suitable for industrial production. The method is suitable for various processing modes.

This invention discloses a polyester material, a heat-shrinkable film, its preparation method, and its applications. The raw materials for preparing the polyester material include a diacid, a diol, a chain extender, a stabilizer, and a catalyst; wherein the diacid comprises: 90 mol%~95 mol% polyterephthalic acid and 5 mol%~10 mol% isophthalic acid; the diol comprises: 65 mol%~78 mol% ethylene glycol, 18 mol%~28 mol% 1,4-cyclohexanediol, and 4 mol%~12 mol% diethylene glycol; the chain extender is 2,2'-(1,3-phenylene)-dioxazoline, added in an amount of 0.2%~0.8% of the total mass of the diol and the diacid; the molar ratio of carboxyl groups to hydroxyl groups in the diacid and the diol is 1:1~1.05. The polyester material of this invention possesses excellent transparency, shrinkage rate, and strength, and has a low initial shrinkage temperature, making it particularly suitable for applications such as heat-shrinkable films. This invention also provides a heat-shrinkable film, as well as the polyester material, a method for preparing the heat-shrinkable film, and their applications.

The invention discloses a preparation method of long-chain branched modified polypropylene, and belongs to the technical field of high polymer materials. The invention discloses a preparation method of long-chain branched modified polypropylene, which is a water phase suspension method and specifically comprises the following steps: adding polypropylene, an acrylic acid n-alkyl ester monomer, an interface agent, a co-monomer, deionized water, an antioxidant and an initiator into a reactor according to a certain weight ratio; the preparation method comprises the following steps: swelling at a certain temperature for a certain time, then carrying out a reaction at a certain temperature for a certain time, and finally washing, extracting and drying. According to the invention, the acrylic acid n-alkyl ester is used as a monomer for long-chain branching modification of polypropylene, and the problem of low melt strength of polypropylene is solved. The method has the advantages of simple process, environmental protection, low cost, good processing effect and the like.