35results about How to "Increased flexural modulus" patented technology

The invention relates to the technical field of composite materials, in particular to a PTFE composite material for a shaft sleeve and a preparation method of the PTFE composite material. The PTFE composite material for the shaft sleeve consists of the following raw materials in parts by weight: 80-140 parts of polytetrafluoroethylene powder, 3-8 parts of polyphenylene sulfide, 8-12 parts of modified glass fibers and 10-15 parts of a reinforcing agent. The lubricating property of a base material is effectively improved by adding the modified glass fiber, and meanwhile, the wear resistance and the mechanical property of the polytetrafluoroethylene composite material are favorably improved by improving the tribological property, enhancing the mechanical strength and improving the interface bonding and load dispersion through the reinforcing agent.

The invention provides a lightweight insulation composite cross arm. The lightweight insulation composite cross arm comprises an insulation core rod, a filler filled in the insulation core rod and an insulation umbrella skirt located outside the insulation core rod, the structure of the insulating core rod is a pipe body formed by modified continuous basalt fibers which are spirally arranged in multiple layers, and resin is adhered to the surfaces of the modified continuous basalt fibers; the structure of the modified continuous basalt fiber is as follows: basalt fiber chips are connected to the surface of the continuous basalt fiber through silica sol; the resin comprises the following raw materials: 100 parts of epoxy resin, 1-5 parts of a silane coupling agent, 5-8 parts of an auxiliary agent, 8-10 parts of basalt fiber chippings, 20-30 parts of a curing agent and 30-50 parts of a solvent. According to the invention, the continuous basalt fibers are modified by the basalt chips, and the basalt chips are used as a bridge, so that the interaction between the continuous basalt fibers and a resin matrix is increased, and the bending modulus and bending strength of the insulating core rod are improved.

The invention discloses a deeply-curable zirconia-containing dental repair resin and a preparation method thereof.The preparation method comprises the steps that a double-bond-containing silane coupling agent is added into a zirconia dispersion liquid and a silicon dioxide dispersion liquid respectively, modification reaction is conducted in the stirring state, and a modified solution # imgabs0 # and a modified solution II are obtained; carrying out spray drying on the modified solution I and the modified solution II through a three-fluid spray head to obtain a zirconium oxide and silicon oxide nanocluster body; uniformly mixing and stirring the zirconium oxide and silicon oxide nanocluster with a methacrylate organic matrix and a photoinitiator; and carrying out light curing treatment on the mixture to obtain the zirconium oxide dental repair resin. The zirconium oxide dispersion liquid, the silicon dioxide dispersion liquid and the three-fluid spray head are matched, the mechanical performance is improved on the premise that the X-ray radiation resistance and the effective curing depth are guaranteed, the dependence of the industry on zinc oxide, barium oxide and strontium oxide is broken through, the problem that a zirconium oxide material cannot be deeply cured due to the high refractive index is solved, and the application prospect is good.

The present invention discloses an LCP resin composition and a preparation method and application thereof, belonging to the technical field of polymer materials. The LCP resin composition comprises the following components in parts by weight: 100 parts of LCP resin, 0.1 to 1 part of a fully aromatic multifunctional oligomer, 10 to 60 parts of glass fiber and 20 to 70 parts of filler; the LCP resin comprises repeating units of the following structure: ‑O‑Ar1‑O‑, ‑OC‑Ar2‑CO‑, ‑O‑Ar3‑CO‑, ‑OC‑Ar4‑CO‑. The present invention uses LCP resin with a trace amount of fully aromatic multifunctional oligomer to form a micro-branched or micro-crosslinked structure, improve the skin-core structure of the LCP resin, destroy the segment regularity of the LCP resin, thereby improving the warping performance of the LCP resin composition and adjusting the bending modulus of the LCP resin composition.

The invention relates to the technical field of epoxy molding compounds, in particular to a low-stress low-hygroscopicity epoxy resin composition and application thereof. The low-stress low-hygroscopicity epoxy resin composition is prepared from the following components: epoxy resin, phenolic resin, inorganic filler, a coloring agent, a release agent, a curing accelerator, an ion trapping agent and a coupling agent, the epoxy resin is composed of o-cresol formaldehyde type epoxy resin and branched diphenyl sulfide epoxy resin, and the branched diphenyl sulfide epoxy resin is obtained by crosslinking 4, 4 '-dihydroxy diphenyl sulfide, inositol and epichlorohydrin; by adding the branched diphenyl sulfide epoxy resin into the epoxy resin composition, the mechanical property and the water absorption rate of the epoxy resin composition are remarkably improved, so that the stability and the reliability of a product are improved, and the epoxy resin composition can be used for packaging small and thin integrated circuits.

The invention discloses a nano-cellulose modified thermoplastic material composite 3D printing consumable and a preparation method, and relates to the technical field of 3D printing consumables, the nano-cellulose modified thermoplastic material composite 3D printing consumable is formed by mixing nano-cellulose modified pecan shell micro powder and a thermoplastic material according to the mass ratio of 1: (4-5); the nano-cellulose modified hickory nut shell micro-powder is prepared from hickory nut shells, talcum powder, nano-cellulose, cationic starch, alkyl ketene dimer, a coupling agent and a lubricating agent. The thermoplastic material is composed of polylactic acid, poly (adipic acid) / butylene terephthalate, a cellulose biological composite material, a flexibilizer and an antioxidant, and the problems that talcum powder and hickory nut powder are not tightly combined and are prone to falling off and components are unstable are effectively solved by adopting the novel separation device; the tight combination and uniform distribution of the talcum powder and the pecan shell micro powder are ensured, so that the compatibility of the talcum powder and the pecan shell micro powder with a thermoplastic material and the overall performance of the composite material are improved.

The invention relates to a compound containing phosphaphenanthrene, an epoxy resin material and a preparation method and application thereof. The structure of the compound is as shown in formula (I): # imgabs0. The compound containing phosphaphenanthrene not only can endow an epoxy resin material with efficient flame retardance, but also can improve the mechanical properties, including impact strength, flexural modulus, flexural strength, elongation at break and tensile strength, of the epoxy resin material. In addition, the preparation method of the compound containing phosphaphenanthrene is simple in synthesis process, free of catalysts in the whole preparation process, simple, easy to implement, low in toxicity, low in pollution and easy to industrialize.

The application discloses a glass fiber reinforced polypropylene composite material and a preparation method thereof. The glass fiber reinforced polypropylene composite material contains the following raw materials in percentage by mass: modified copolymerized polypropylene 45.5%-75%, glass fiber 10%-26%, toughening agent 3%-9%, coupling agent 3.5%-12.0%, compatibilizer 4%-7% and stabilizer 0.4%-0.6%; wherein, the coupling agent contains at least two primary amines, and the modified copolymerized polypropylene contains aldehyde groups. The glass fiber reinforced polypropylene composite material provided by the application forms a macromolecular network structure with reversible cross-linking through mutual cooperation between the raw materials, significantly improves the notched impact strength of the glass fiber reinforced polypropylene composite material on the basis of improving the strength and low-temperature resistance of the glass fiber reinforced polypropylene composite material, and has excellent comprehensive performance.

The application discloses a nylon composition and a preparation method and application thereof, and belongs to the technical field of polymer engineering plastics; the nylon composition provided by the application comprises the following components in parts by mass: 73-92 parts of PA12 resin, 3-22 parts of a toughening agent, 0.3-1.8 parts of lignosulfonate, and 0.1-1.2 parts of polyvinylpyrrolidone; the toughening agent comprises maleic anhydride grafted SEBS. The product prepared by the application has high light transmittance and excellent bending modulus and impact strength; meanwhile, the preparation method of the nylon composition is simple in operation and is beneficial to actual production.

The invention relates to a low-melting high-impact polypropylene special material and a production process thereof. The problems of poor normal and low temperature impact resistance, low flexural modulus and fast catalyst activity attenuation of polymers in the prior art are mainly solved. The process comprises the following steps: step A, prepolymerization reaction: prepolymerizing a catalyst and propylene to generate a prepolymerization product under prepolymerization reaction conditions; step B, homopolymerization reaction: under the action of a catalyst, the prepolymerization product is subjected to homopolymerization reaction in a multi-zone circulation reactor, and polymer basic powder is obtained under polymerization process conditions; step C, gas phase copolymerization reaction: the polymer basic powder enters a gas phase reactor, and further reacts with propylene and ethylene by utilizing the residual activity of a catalyst to generate impact-resistant copolymer powder; and D, blending, extruding and granulating to obtain a target product. The low-melting high-impact polypropylene special material prepared by the process has excellent normal and low temperature impact resistance, high strength and good processability.

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 utility model discloses a kind of tensile tear-resistant reinforced CPVC cable protection pipe, it includes pipeline, the inside fixed connection of pipeline has CPVC resin, the inside fixed connection of CPVC resin has nano calcium carbonate, the inside fixed connection of nano calcium carbonate has calcium-zinc stabilizer.Through the above structure, there is a layer of CPVC resin in pipeline, the smooth surface of CPVC resin can reduce the contact area of cable and pipe wall, reduce the local temperature rise caused by heat generation due to friction, while the air gap between pipe wall and cable is more uniform, beneficial to the heat dissipation of cable operation, prolong the service life of cable, there is also a layer of nano calcium carbonate in it, nano calcium carbonate particle size is usually 10~100nm, specific surface area is large and dispersibility is good, uniformly filled in CPVC resin matrix can form "rigid particle reinforcing effect", the tensile strength of inner wall layer is improved by 20%~30%, and bending modulus is improved by 15%~25%.

The invention relates to the field of propylene polymerization, and discloses a preparation method of polypropylene, polypropylene and application. The method comprises the following steps: S1, in the presence of a functional external electron donor and a catalyst system, carrying out a prepolymerization reaction on propylene to obtain a prepolymer A; the prepolymerization multiplying power is 1000 to 10000 times; s2, in the presence of a first molecular weight regulator, a first external electron donor and the prepolymer A, performing a first polymerization reaction on propylene to obtain a polymer B; s3, in the presence of a second molecular weight regulator, a second external electron donor and a polymer B, carrying out propylene second polymerization reaction to obtain polypropylene. According to the method, the prepolymerization reaction is combined with the polymerization reaction of two stages, the functional external electron donor is introduced in the prepolymerization process, and the specific first external electron donor and the specific second external electron donor are subsequently matched, so that the prepared polypropylene has good processability and heat resistance.

This application provides a glycourea polythiol curing agent composition, relating to the field of polymer materials technology. The composition comprises a mixture of a glycourea trithiol compound and a glycourea dithiol compound consisting of positional isomers. This composition, used as a curing agent for epoxy resin compositions, can form a highly uniform cross-linked network structure, enabling the cured epoxy resin composition to simultaneously possess a high glass transition temperature, high flexural modulus, and ultra-high fracture toughness, achieving an excellent balance between rigidity and toughness.

The invention discloses a composite material for a frame structure and a preparation process of the composite material. The composite material comprises the following components in parts by weight: 100-200 parts of caprolactam, 30-40 parts of treated glucan, 5-10 parts of a black phosphorus-graphene composite material, 10-20 parts of an inorganic filler and 1-2 parts of a cross-linking agent. Glucan is added to replace part of light filler, the density of the material is reduced, good bending modulus is kept, the material can still keep good mechanical performance while the weight is reduced, the toughness of graphene is greatly improved through the lubricating effect of black phosphorus, and the service life of the material is prolonged. The mechanical property of the composite material is improved through covalent bond crosslinking generated by the two, and the prepared composite material for the frame structure is expected to be widely applied to the aspect of automobile light weight.

The application discloses a kind of high-strength nylon 66 materials and preparation method thereof, belong to high polymer material technical field.The application is directed to the problem that high-strength nylon 66 material is difficult to consider flame-retardant performance, provide a kind of high-strength nylon 66 material, it includes by the nano cellulose of phytic acid and metal ion chelation modification.The modified nano cellulose, phytic acid and metal ion form chelation layer of three-dimensional network structure on the surface of nano cellulose, significantly improve the compatibility of nano cellulose and nylon 66.The application also provides the preparation method of the high-strength nylon 66 material.The nylon 66 material obtained by the application has a tensile strength greater than 100 MPa while meeting the UL-94 V-0 flame-retardant grade, achieving a good balance between high strength and flame-retardant performance, and can be applied in new energy vehicle connectors, electronic and electrical enclosures, aviation interior parts and other fields.

The present invention relates to the technical field of polycarbonate, and discloses a flame-retardant modified polycarbonate material and a preparation process of a glass fiber composite material, including 100 parts by weight of polycarbonate, 0.05-0.3 parts by weight of hexa(sulfonic acid carbazole aniline) cyclotriphosphazene, and 2-20 parts of quaternary ammonium salt modified glass fibers; the present invention modifies the hexa(sulfonic acid carbazole aniline) cyclotriphosphazene flame retardant to the surface of the glass fiber. The two form a flame-retardant glass fiber composite material, which significantly improves the limiting oxygen index of polycarbonate, and the UL94 fire rating reaches V-0 level. The modified glass fiber surface is modified with an organic functional group, which improves the compatibility with polycarbonate, so that the glass fiber can be evenly dispersed in a polycarbonate matrix, and its reinforcing effect is more effectively exerted, thereby improving the tensile strength and flexural modulus of the polycarbonate.

The invention provides a high-melting-point and high-hardness polycarbonate material and a preparation method thereof, the high-melting-point and high-hardness polycarbonate material comprises the following components: polycarbonate diol, a chain extender, diisocyanate, a catalyst, a lubricant, an antioxidant, an auxiliary material and a light stabilizer, the chain extender comprises 1, 4-butanediol or 1, 4-cyclohexanedimethanol, and the catalyst comprises 1, 4-butanediol or 1, 4-cyclohexanedimethanol. Compared with an existing chain extender which mostly selects BDO and cannot meet the characteristics of high hardness and high melting point at the same time, symmetric alicyclic dihydric alcohol 1, 4-cyclohexanedimethanol is selected as a micromolecule chain extender, the chain extender is resistant to high temperature, high in deformability, high in melting point and good in transparency, and by combining control over the temperature, moisture and reaction time of the technology, the hardness and the melting point of the chain extender are greatly improved. And finally, the high-temperature-resistant polycarbonate material with high hardness and high melting point is obtained.

The application relates to a high-rigidity PC alloy material and a preparation method and application thereof, and the PC alloy material comprises the following components and weight contents: 40-80 parts of PC resin, 10-20 parts of high-temperature nylon, 10-40 parts of short-cut carbon fiber, 2-6 parts of a compatilizer, and 0.1-1 part of other additives. The preparation method is that the components are uniformly stirred in a mixing barrel, and are added into a double screw through a main feeding port; the short-cut carbon fiber is added into an extruder through a side feeding port, is extruded and granulated through the extruder, and the high-rigidity PC alloy material is obtained. Compared with the prior art, the application can greatly improve the bending modulus of the material, improves the reinforcing effect of the short-cut carbon fiber, thereby improving the rigidity of the material, and plays a role of replacing steel with plastic.

The invention discloses an anti-corrosion and high-weather-resistant alloy resin tile and a preparation process thereof. The preparation process comprises the following steps: S1, preparing a basic composite material; s2, adding vanadium oxide and zinc oxide composite nanoparticles prepared by a sol-gel method into the basic composite material; s3, introducing a dynamic cross-linked fluorosilicon-based polymer, and preparing a surface layer functional material through a dynamic cross-linking technology; s4, forming a multi-layer structure base material; s5, preparing a multi-layer co-extrusion tile material; s6, the interlayer binding force of the multi-layer co-extrusion tile material is enhanced through the ultrasonic activation bonding technology; s7, depositing a fluorinated graphene nano film by using a plasma enhanced chemical vapor deposition technology; and S8, crack detection and aging state real-time sensing are completed by combining the conductive polythiophene composite layer embedded in the bottom layer with an intelligent monitoring module. The preparation of the corrosion-resistant and high-weather-resistant alloy resin tile is realized by utilizing a bio-based material, multi-layer co-extrusion and an intelligent monitoring technology.

The invention relates to the field of polymer composite materials, the field of photo-curing materials, photo-thermal synergistic curing resin, a glass fiber composite material and a preparation method of the glass fiber composite material, in particular to a preparation method of a near-infrared cured high-performance acrylate-epoxy matrix glass fiber composite material. The network connecting agent with acrylic ester and glycidyl ether is specially added into a hybrid resin matrix to promote connection of two cross-linked networks so as to obtain the composite material with more excellent performance. A glass fiber laminate prepared on the basis of the resin composition provided by the invention; the bending strength and the bending modulus are obviously improved, and the bending strength can be improved by 30%. The invention also provides a preparation method of the glass fiber laminated board, a curing light source uses near-infrared light to directly initiate deep photocuring, and the method for preparing the glass fiber laminated board is simple in process and suitable for industrial production.

This invention belongs to the field of composite material technology. This invention provides a toughening agent material and its preparation method. The preparation method includes the following steps: S1, adding 10.8-11 parts by weight of polyacrylate-calcium carbonate toughening agent, 100 parts of polyvinyl chloride, 3.5-4 parts of stabilizer, 1.3-1.5 parts by weight of aluminum-modified nano-titanium dioxide, and 2-2.3 parts by weight of maleic anhydride-modified chlorinated polyethylene to a high-speed mixer and stirring to obtain a mixed base material; S2, plasticizing and molding the mixed base material obtained in S1 using a rubber mixing mill and a flat vulcanizing machine, then cooling and demolding to obtain the toughening agent material. This invention increases the amount of polyacrylate-calcium carbonate toughening agent to improve the flexural modulus of the prepared composite material while further improving its notched impact strength.

The invention discloses a seamless welding broken bridge aluminum door and window heat insulation strip and a preparation method thereof, and relates to the technical field of organic materials. The invention discloses a preparation method of a seamless welding broken bridge aluminum door and window heat insulation strip, which is characterized by comprising the following steps: premixing an antioxidant, a lubricant, a grafting solubilizer, an automobile water tank recycled PA66 material and black sand according to the proportion of raw material components, adding PA10T resin and modified glass fiber, blending, extruding, granulating and drying to obtain an alloy material; and molding the alloy material to obtain the seamless welding broken bridge aluminum door and window heat insulation strip. The heat insulation strip prepared by the invention has the characteristics of excellent mechanical property and good temperature resistance.

The invention relates to the technical field of polymer composite materials, in particular to a preparation method of high-impact-resistance PVC (polyvinyl chloride) composite resin, which comprises the following steps: step 1, adding nano calcium carbonate into a high-speed mixer, and spraying a treating agent twice to form a composite interface layer; step 2, mixing the product in the step 1 and PVC resin at a temperature lower than a glass-transition temperature in a segmented manner, so that the nano particles are embedded into pores of the PVC primary particles; step 3, adding an acrylic elastomer (ACR) emulsion into a product in the step 2, and controlling an ACR molecular chain migration path through a dynamic temperature field; and 4, dropwise adding a siloxane cross-linking agent containing an epoxy group into the system in the step 3 in an inert atmosphere, and monitoring and controlling the cross-linking reaction process in real time through the rheological property. By finely controlling the temperature, the mixing rate and the cross-linking reaction process in each step, the stability of the production process is improved, the production cost is reduced, and the reject ratio of finished products is reduced.

The invention relates to the technical field of double-wall corrugated pipes, in particular to a polyolefin alloy material double-wall corrugated pipe which comprises a double-wall corrugated pipe body, a first connector and a second connector are arranged at the two ends of the double-wall corrugated pipe body respectively, the first connector comprises an inner cylinder arranged at a port of the double-wall corrugated pipe body in a communicating mode, and an outer cylinder is arranged on the outer side of the inner cylinder in a sleeving mode. An inner ring is arranged in an annular space defined by the outer cylinder and the inner cylinder in a sliding mode, a straight cylinder arranged on the inner cylinder in a sliding and sleeving mode is arranged on the inner ring, a conical opening is formed in an end opening of the straight cylinder, the second connector is a cylinder body installed on the end face of the other side of the double-wall corrugated pipe body, and threads are arranged on the outer wall of the cylinder body; when the second connector is connected with the first connector, the second connector is inserted into the outer cylinder and meshed with the inner wall of the outer cylinder in a threaded mode, when the second connector is connected with the first connector, due to the fact that the second connector pushes the conical opening, the inner ring moves inwards to stretch the spring, and the elastic force of the spring is utilized to enable the conical opening to be in contact with the inner wall of the second connector all the time.

The present invention provides a high heat-resistant and high-barrier PA6 / COC composite material and a preparation method thereof, wherein the PA6 / COC composite material comprises the following components by weight: 65-80 parts of PA6; 15-25 parts of COC; 6-10 parts of modified filler; 0.5-1.5 parts of nucleating agent; 4-8 parts of toughening agent; 0.5-2 parts of lubricant; 0.2-1.0 parts of antioxidant. The present invention adopts high-viscosity PA6 as the first matrix resin and COC as the second matrix resin, improves the solvent resistance of PA6 by COC, adds a nucleating agent to improve the crystallinity of the alloy material, further improves the rigidity, heat resistance, solvent resistance and barrier properties of the material, and adopts an appropriate toughening agent and lubricant system to balance the rigidity, toughness and processing properties of the material, so that the finally prepared PA6 / COC composite material has high heat resistance, excellent solvent resistance and good barrier properties.

The application provides kaolin-barium sulfate nanocomposite powder and a preparation method and application thereof, and belongs to the technical field of inorganic nanocomposites. The kaolin-barium sulfate nanocomposite powder comprises single-layer kaolin nanosheets and barium sulfate nanoparticles deposited on the surface of the single-layer kaolin nanosheets; the thickness of the single-layer kaolin nanosheet is 1-10 nm, and the planar size is 100-500 nm; and the particle size of the barium sulfate nanoparticles is 10-50 nm. The kaolin nanosheet is used as a two-dimensional base to spatially isolate the barium sulfate nanoparticles and prevent migration and agglomeration of the barium sulfate nanoparticles; meanwhile, the surface-anchored barium sulfate nanoparticles serve as nanoscale spacing columns to physically block face-to-face restacking of the kaolin nanosheets, and the two are stable to each other, so that the dispersion problem of the two kinds of nanomaterials is fundamentally solved.

The invention relates to the technical field of high polymer material assistants, in particular to a preparation method and application of an anti-reflection polypropylene nucleation assistant.The anti-reflection polypropylene nucleation assistant.The anti-reflection polypropylene nucleation assistant.The anti-reflection polypropylene nucleation assistant.The anti-reflection polypropylene nucleation assistant.The anti-reflection polypropylene nucleation assistant.The anti-reflection polypropylene nucleation assistant.The anti-reflection polypropylene nucleation assistant.The anti-reflection polypropylene nucleation assistant.The preparation method has the advantages that the anti-reflection polypropylene nucleation assistant.The anti-reflection the surface lipophilicity is improved, the compatibility with a polypropylene matrix and a sorbitol nucleating agent is remarkably improved, and the problem of poor dispersity is solved; the sorbitol nucleating agent provided by the invention and an inorganic nanoparticle compounded system generate a synergistic effect, and compared with a single nucleating agent, the sorbitol nucleating agent provided by the invention can reduce fog of a polypropylene product, improve impact strength and improve flexural modulus; the composite nucleating agent provided by the invention can stably play a role at 180-200 DEG C, compared with a traditional nucleating agent, the processing temperature is reduced, the processing energy consumption is reduced, and the composite nucleating agent has a wide application prospect.

The invention discloses a PC / ABS material with high impact and low linear expansion coefficient and a preparation method thereof, and belongs to the technical field of high polymer materials. The preparation method comprises the following steps: uniformly mixing 53-68 parts of PC resin, 10-32 parts of ABS resin, 3-6 parts of a flexibilizer, 0.5 part of a compatilizer, 0.5 part of an antioxidant, 0.5 part of a lubricant and 0.5 part of carbon black, feeding the obtained mixture through a main feeding port of a double-screw extruder, feeding 10-20 parts of silane modified talcum powder through a side feeding port, extruding, granulating, cooling and drying to obtain the PC / ABS material with high impact and low linear expansion coefficient. The material has high tensile strength and flexural modulus and extremely low linear expansion coefficient, and can meet the requirements of good dimensional stability and good appearance performance at the same time.

This invention relates to the field of propylene polymerization, and discloses a method for preparing polypropylene and its applications, as well as polypropylene and its applications. The method includes: S1, conducting a first polymerization reaction of propylene in the presence of a first molecular weight regulator, a first external electron donor, a functional external electron donor, and a catalyst system to obtain polymer A; S2, conducting a second polymerization reaction of propylene in the presence of a second molecular weight regulator, a second external electron donor, and polymer A to obtain polypropylene; the amount of the first molecular weight regulator is less than the amount of the second molecular weight regulator. This method introduces a functional external electron donor during the first polymerization process, while simultaneously controlling the first and second external electron donors to meet specific types and controlling the amount of molecular weight regulator at different polymerization stages, enabling the obtained polypropylene to possess both good processing properties and heat resistance.