12 results about "Isothermal crystallization" patented technology

The invention relates to a large-size glass product with a natural ice crystal imitating effect and an industrial casting method of the large-size glass product. The product is a lead-free glass casting with the weight larger than or equal to 100 kg, dendritic crystal-shaped or snowflake-shaped devitrified phases which are formed by growing calcium fluoride as crystal nucleuses and are distributed randomly are arranged in the product, and the three-dimensional aesthetic effect imitating natural ice crystals is achieved. The method comprises the following steps: mixing lead-free glass particles with a calcium fluoride nucleating agent with a specific particle size, and filling a mixture into a special mold with a three-layer composite structure and a temperature monitoring function; and executing a four-stage programmed thermal regulation including melting homogenization, nucleation cooling, isothermal crystallization and super-slow multi-step annealing, wherein the melting and heat preservation time and the maximum thickness of the product meet the quantitative relation of t = k.H. Through systematic collaboration of materials, molds and processes, the technical problems that crystallization in large-size glass is not uniform and cracking is easily caused by thermal stress are solved, high yield and stable mass production of products of 500 kg or above are achieved, and the method is suitable for the fields of high-end buildings, art devices and decoration.

The present application relates to a kind of polyethylene terephthalate foamed materials and its preparation method, the preparation method includes the following steps: polyethylene terephthalate material is heat pressed, and the preform of molten state is obtained;The preform of molten state is treated with melt isothermal crystallization and quenching, and sheet material is obtained;And the sheet material is treated with foaming, and polyethylene terephthalate foamed material is obtained.The present application uses melt isothermal crystallization treatment, can improve the melt strength in the foaming process of polyethylene terephthalate, strengthens its foaming performance, simultaneously can also be realized by strengthening bubble nucleation and controlling bubble growth to adjust the bubble morphology of foamed material, so can obtain the polyethylene terephthalate foamed material of bubble size uniform and controllable foaming ratio.

The present application relates to a kind of polyethylene terephthalate-2,5-furandicarboxylic acid glycol copolyester foamed material and its preparation method, the preparation method includes the following steps: polyethylene terephthalate-2,5-furandicarboxylic acid glycol copolyester material is heat pressed, and the preform of molten state is obtained;The preform of molten state is treated with melt isothermal crystallization and quenching, and sheet material is obtained;Sheet material is treated with foaming, and polyethylene terephthalate-2,5-furandicarboxylic acid glycol copolyester foamed material is obtained.The present application uses melt isothermal crystallization treatment, can improve the melt strength in the foaming process of polyethylene terephthalate-2,5-furandicarboxylic acid glycol copolyester, strengthens its foaming performance, simultaneously can also be realized by strengthening bubble nucleation and controlling bubble growth to adjust the bubble morphology of foamed material, so polyethylene terephthalate-2,5-furandicarboxylic acid glycol copolyester foamed material with uniform bubble size and controllable foaming ratio can be obtained.

A method for improving the nucleation of the γ phase in polyvinylidene fluoride (PVDF), a γ phase PVDF dielectric film based on the nucleation method, and a preparation method thereof are disclosed. The method involves using ceramic powder in the PVDF film material to enhance the nucleation ability of the γ phase crystals, improve the hydrophilicity of the PVDF film, and enhance the high-temperature dielectric properties of the PVDF film material. The dielectric film raw materials include 0-0.2 parts of ceramic powder (NBT), 10 parts of polyvinylidene fluoride (PVDF), and 200-204 parts of N,N-dimethylformamide (DMF). The preparation method is as follows: 1) Using N,N-dimethylformamide... 1) Prepare a 5% ceramic powder / polyvinylidene fluoride solution using amide as a solvent; 2) Drop the solution from step 1) onto a glass slide and cure it into a film in a vacuum oven at 68-72℃; 3) Melt the cured film obtained in step 2) on a hot stage at 200℃-220℃ to eliminate thermal history, and then rapidly cool it to 150-170℃ for isothermal crystallization until the blended film is completely crystallized; The preparation method of the γ-phase polyvinylidene fluoride dielectric film of the present invention is simple, convenient to operate, and has excellent performance, such as high temperature resistance, corrosion resistance, and strong piezoelectricity and ferroelectricity.

This application relates to a high-melting-point, high-whiteness methyl octabromoether flame retardant composition and its preparation method, belonging to the fields of fine chemicals and flame retardant preparation technology. The method includes: etherifying tetrabromobisphenol A, sodium hydroxide, and allyl chloride; purifying the mixture by isothermal crystallization at 30–50°C to obtain a tetrabromoether intermediate; dissolving the intermediate in dichloromethane and reacting it with bromine at 10–40°C; and finally, obtaining the finished product through post-treatment. This invention effectively removes impurities such as monoethers through a specific intermediate crystallization process, and avoids overheating and oxidation side reactions by combining low-temperature bromination and optimized solvent ratios. The obtained flame retardant has a melting point ≥106°C, whiteness R457 ≥92, and bromine content ≥67%, exhibiting advantages such as good thermal stability, low volatility, and high purity. The process conditions are mild and suitable for industrial production.

The invention discloses a production process for preparing copper acetate from pure copper by a one-step method, which belongs to the technical field of copper acetate, and comprises the following steps: adding modified copper powder into a reaction kettle, adding an acetic acid aqueous solution in a nitrogen atmosphere, stirring for pre-dispersion, adding a compound additive, and continuously stirring; raising the temperature and stirring at normal pressure, and supplementing an acetic acid aqueous solution during stirring; performing centrifugal separation to obtain copper acetate coarse crystals and mother liquor, and performing filtration and cation exchange resin column treatment on the mother liquor for recycling; adding water into the coarse crystal for recrystallization, heating, stirring and filtering, cooling and crystallizing the filtrate, centrifuging, and carrying out vacuum drying on the final crystal to obtain copper acetate. The whole process does not produce by-products such as sodium sulfate and alkali-containing wastewater, and the mother liquor can be recycled after being filtered and treated by the cation exchange resin column, so that the raw material consumption and the waste liquor discharge are reduced, the wastewater treatment cost is effectively reduced, and the development concept of green chemical industry is met.

The present application provides a kind of detection method of ash in asphalt.The detection method includes: step S1: raw materials including asphalt and dispersant are heated and mixed in sequence to obtain melt;Step S2: melt is crystallized to obtain asphaltene crystal;Crystallization treatment includes temperature drop and isothermal crystallization treatment in sequence;The temperature drop rate of temperature drop is ≤5℃ / min;Step S3: asphaltene crystal is phase separated to obtain crystalline phase;Step S4: crystalline phase is ashed to obtain ash;The temperature of ashing treatment is ≤200℃;Step S5: ash is detected to obtain the composition and mass content of ash.The detection method of the present application can realize efficient enrichment of ash and very low background interference, can detect most of the trace metal elements in ash, and has good accuracy and repeatability, thereby better meeting the quantitative detection needs of high-quality asphalt for very low ash content.

This invention belongs to the field of polymer testing and analysis technology, specifically a method for rapidly characterizing the chain structure of metallocene linear low-density polyethylene. The method includes: determining the crystallization curve of a sample under non-isothermal crystallization conditions using a differential scanning calorimeter; decomposing the crystallization curve into three characteristic regions: region A associated with the crystallization of longer methylene sequences; region C associated with the crystallization of very short methylene sequences; and the remaining region B associated with the crystallization of intermediate-length methylene sequences. The proportion of each region's area in the total crystallization area is calculated based on the area of ​​each of the three regions. I A , I B and I C ;use I A , I B and I C The magnitude of the value can characterize the relative content of long, short, and very short crystallizable methylene sequences in the mLLDPE, thereby assessing the uniformity of comonomer distribution along its macromolecular chain. This invention features a simple, fast, and low-cost analytical process, making it particularly suitable for quality management in mLLDPE production and application companies.

Provided is a polyarylene sulfide resin composition that has excellent resistance to heat and humidity and molding properties without reducing mechanical strength and the like. More specifically, the present invention is characterized by comprising a polyarylene sulfide resin, glass fibers that have been surface-treated with a sizing agent comprising an epoxy resin and a polyether resin, and a silane coupling agent having a functional group, the total content of the epoxy resin and the polyether resin in the aforementioned sizing agent being 65 to 100 mass%, and the isothermal crystallization time of the polyarylene sulfide resin composition being 9 seconds or less.

The application discloses a method for regulating and controlling micro-nano patterns of crystalline block copolymer, which comprises the following steps: a solution of polyethylene oxide-poly(2-vinylpyridine) (PEO-P2VP) block copolymer is spin-coated on a silicon wafer to obtain a PEO-P2VP film; the spin-coated film is annealed at different temperatures, and then is placed into a Linkam hot stage to perform melt isothermal crystallization; by changing the annealing temperature, the melt temperature of melt heat treatment and the melt time, the lamellar patterns in the PEO-P2VP film can be regulated and controlled. b The PEO-P2VP block copolymer is poly(ethylene oxide)-poly(2-vinylpyridine). b The PEO-P2VP block copolymer is poly(ethylene oxide)-poly(2-vinylpyridine). b The PEO-P2VP block copolymer is poly(ethylene oxide)-poly(2-vinylpyridine). b The PEO-P2VP block copolymer is poly(ethylene oxide)-poly(2-vinylpyridine). The method has the advantages of simple operation, low equipment requirement, and the ability to form nano-pattern arrays with controllable density, size and morphology on a large area, which opens up new possibilities for the application of multifunctional nano materials, and has extremely important significance for the future development of block copolymer materials.

The invention discloses a preparation method and application of a carbon fiber / polypropylene composite material with a self-reinforced interface, and belongs to the technical field of composite materials. The preparation method of the carbon fiber / polypropylene composite material with the self-reinforced interface comprises the following steps: impregnating carbon fibers in molten polypropylene; cooling to a pre-forming temperature, and stretching the carbon fibers at a rate of 40-300 [mu] m / s; continuously cooling to a forming temperature, and carrying out isothermal crystallization; and cooling to room temperature to obtain the carbon fiber / polypropylene composite material with the self-reinforced interface. The contents of alpha and beta crystal forms in an interface transverse crystal are regulated and controlled in a manner of stretching the carbon fiber at different rates and giving a shear force to a matrix in a pre-forming stage, so that the interface bonding performance of the carbon fiber / polypropylene composite material is improved, the designability and the regulation and control of the comprehensive performance of the carbon fiber / polypropylene composite material are improved, and the industrial application diversity is met.

An unnucleated metallocene polypropylene having: (i) a melting temperature of from about 153 °C (307 °F) to about 183°C (361.4 °F); (i) a heat deflection temperature of from about 98.9°C (210°F) to about 129.4 °F (265°F); (iii) a lower temperature bound for the isothermal crystallization temperature of from about 120 °C (248°F) to about 154°C (309.2°F); (iv) a flexural modulus of from about 200 kpsi to about 330 kpsi; and (v) a tensile modulus of from about 220 kpsi to about 325 kpsi; and (vi) a tensile strength at yield of from about 4800 psi to about 5900 psi.