7 results about "Chain propagation" patented technology

This invention discloses a two-color injection molding process for Tritan material, belonging to the field of injection molding technology, which solves the problem of easy delamination and fusion lines in two-layer injection molding of the same Tritan material. The injection mold used in this process includes a male mold, a first injection mold, and a second injection mold. The workpiece includes a transparent inner layer and a transparent outer layer. The steps include: S1. Injecting molten Tritan raw material into the first injection mold heated to 100-130°C to form a transparent inner layer; S2. Cooling the first injection mold to 35-50°C, after mold opening, the transparent inner layer remains in the male mold and rotates 180 degrees to close with the second injection mold, so that the residual temperature of the transparent inner layer is maintained at 35-50°C; S3. Injecting molten Tritan raw material into the second injection mold heated to 100-130°C to form a transparent outer layer on the outer wall of the transparent inner layer; S4. Cooling and solidification; S5. Demolding. This invention achieves molecular chain diffusion and entanglement at the interface of inner and outer layer materials by precisely controlling the temperature of two injection molding processes, resulting in a product with strong interlayer bonding, high transparency, and rich visual effects in a single molding process.

The invention belongs to the technical field of hydraulic oil, and particularly relates to a polymethacrylate type hydraulic oil viscosity index improver and a preparation method thereof. By adopting ultraviolet light with a specific wavelength (200-400 nm, preferably 254 nm or 365 nm) to assist initiation, side reactions such as thermal degradation, oxidation and the like caused by high temperature in the traditional thermal polymerization process are remarkably inhibited. And the relative stability of the monomer concentration is maintained by combining ultraviolet initiation with a dropwise adding process, so that the chain propagation reaction is more stable and uniform. Under a regular polymerization structure initiated by ultraviolet light, through copolymerization of alkyl ester monomers of methacrylic acid C1-C4, C5-C12 and C13-C24 and olefin monomers in a specific molar ratio, a remarkable synergistic effect is generated. According to the structure, the pour point (the lowest temperature reaches-52 DEG C) and the low-temperature viscosity (KV-18) of hydraulic oil are remarkably reduced through effective containing of the long-chain alkyl ester, and the mechanical shear resistance of the polymer is enhanced through the regular chain structure of the long-chain alkyl ester.

The invention belongs to the technical field of packaging material processing, and particularly relates to a hot melting bonding method of a PET, PE and PP multi-layer composite packaging film. The method aims to solve the problems of solvent residue, poor interfacial compatibility, low bonding strength, thermal stress wrinkling and the like in the traditional compound process. The surface energy of each film layer is improved through multi-stage plasma surface pretreatment, and a functional nano composite adhesive containing near-infrared absorption nanoparticles is coated; the thickness of the bonding layer is controlled to be 2-5 microns by adopting micro gravure coating; after pre-pressing, high-strength near-infrared radiation is used for carrying out instantaneous selective heating on a bonding interface, so that a bonding layer is melted, and molecular chains are promoted to be diffused and entangled. Solvent-free compounding is achieved, the peel strength reaches 12 N / 15 mm or above, the production speed exceeds 150 m / min, the bonding strength, the appearance flatness and the production efficiency are remarkably improved, online nondestructive quality monitoring is supported, and the method is suitable for manufacturing of high-speed, environment-friendly and high-quality multilayer composite films.

The invention discloses a waterproof moisture-permeable composite structure membrane based on mixed solvent regulation and control and a preparation method, and belongs to the technical field of materials. The preparation method of the waterproof moisture-permeable composite structure membrane comprises the following steps: carrying out electrostatic spraying on a polyurethane nanofiber membrane base material with a low-surface-energy polyurethane spraying solution, so as to obtain the waterproof moisture-permeable composite structure membrane, wherein a solvent used by the polyurethane spraying solution is formed by mixing a solvent used by the polyurethane spinning solution and diacetone alcohol; according to the mixed solvent method, a polyurethane fiber base material is swelled, molecular chain diffusion and entanglement between the base material and an electrostatic spraying product interface are promoted, so that the bonding force between the composite structure interfaces is improved, and a wafer and cylinder multi-scale composite structure is innovatively formed on a polyurethane nanofiber membrane; the wear resistance, stripping resistance and overall durability of the composite structure layer are improved; the lyophobic performance of the prepared waterproof moisture-permeable composite structure film is further improved, the durability is improved, and therefore the waterproof moisture-permeable composite structure film can be better and practically applied to the field of medical and defense protection.

The invention discloses a weather-resistant reinforced composite fiber material and a preparation method thereof, and belongs to the field of polypropylene fibers. The weather-resistant reinforced composite fiber material comprises the following raw materials in parts by mass: 60-80 parts of polypropylene resin, 30-40 parts of montmorillonite intercalation modified particles, 0.5-2 parts of a light stabilizer, 0.5-2 parts of an antioxidant, 1-3 parts of a lubricant and 4-8 parts of a plasticizer, the montmorillonite intercalation modified particles are prepared from polypropylene and modified montmorillonite through a melt intercalation method; a long-chain alkyl silane chain segment and a phosphate group are grafted on the modified montmorillonite. A polypropylene molecular chain is diffused into montmorillonite layers through a melt intercalation method to form a nano-scale intercalation structure, and then the nano-scale intercalation structure and polypropylene resin are subjected to composite melt spinning to form a nano-scale barrier layer, so that the crystallinity of polypropylene is improved, the mechanical property of the material is improved, and the weather resistance of the material is enhanced. Montmorillonite is subjected to modification treatment, so that intercalation of a polypropylene molecular chain and improvement of thermal oxidation stability can be promoted.

Disclosed in the present application are a block copolypeptide, a polymer fiber, and a preparation method therefor and the use thereof. The block copolypeptide comprises a dendritic polymer and a polypeptide chain linked to the dendritic polymer, wherein the polypeptide chain consists of a structural unit as represented by formula (I) and a structural unit as represented by formula (II), the dendritic polymer is linked to the structural unit as represented by formula (I) via an amide bond, and the structural unit as represented by formula (I) is linked to the structural unit as represented by formula (II) via an amide bond. The block copolypeptide of the present application enables functional units which would otherwise form a β-sheet conformation to undergo chain propagation in a metastable α-helix state, and subsequently converts the metastable α-helix into a β-sheet, thus exhibiting a good stability. The formed polymer fiber has superior mechanical properties, and can be widely used in key fields such as high-toughness composite materials, degradable biomedical materials, and intelligent drug delivery systems.