5results about How to "Raise the transition temperature" patented technology

This invention discloses a sealing glass with good wettability to titanium alloys, comprising the following components in weight percentage (wt.%): 30-50 wt.% SiO2, 1-5 wt.% Al2O3, 10-30 wt.% B2O3, 10-20 wt.% TiO2, 5-9 wt.% CaO, 1-5 wt.% SrO, 0.1-0.5 wt.% BaO, 2-8 wt.% ZrO2, 1-2 wt.% La2O3, 0-1 wt.% CeO2, and 0.1-0.5 wt.% CoO. This invention also provides a method for preparing sealing glass, comprising the following steps: weighing raw materials according to a mass percentage of a glass composition, mixing them evenly, heating and melting them into a glass melt; after the glass melt is uniform, pouring the molten glass melt into deionized water for rapid cooling and quenching, then drying to obtain glass melt fragments; then ball milling the dried glass fragments into glass powder, drying and sieving to ensure the glass powder particle size is less than 100 micrometers, thus obtaining the desired sealing glass material powder. This invention has a linear thermal expansion coefficient of (50-70)×10⁻⁶ in the range of 20-300 °C. ‑7 / ℃; glass softening temperature is 610-660℃; advantages include chemical stability of level IV or above.

The invention discloses a polysiloxane-based shape memory polymer and a preparation method thereof, and belongs to the technical field of shape memory polymer synthesis. The method comprises the following steps: sequentially adding a formaldehyde solution, a solution dissolved with siloxane and 2-naphthol into a container, and reacting at 90-100 DEG C for 1.5-3 hours; removing the solvent through reduced pressure distillation, then washing liquid residues for multiple times by using deionized water to obtain a product, and drying the product at 60 DEG C for 6 hours to obtain viscous liquid; the liquid is placed in a mold, then the mold is transferred into a drying oven, the temperature is increased to 120 DEG C and 140 DEG C in sequence, heat preservation is conducted for 1 h, finally, the temperature is increased to 190 DEG C to 220 DEG C, the temperature is kept for 5 h to 6.5 h, and curing is completed. The shape memory polymer formed by polymerizing siloxane and 2-naphthol has more Si-O groups, benzene rings and oxazine rings, the groups can enhance the tolerance of the polymer to high temperature, chemical or physical crosslinking points serve as a stationary phase to memorize a permanent shape, and a flexible alkyl-siloxane unit serves as a switching section to fix a temporary shape.

A method for improving phase transition temperature of 4D printing high-temperature high-entropy shape memory alloy, comprising the following steps: firstly, forming Ti 25 Zr 12 Hf 13 Ni 25 Cu 18 Co7 high-temperature high-entropy shape memory alloy by using 4D printing technology T S and then heating the printed alloy sample to semi-solid temperature between solidus temperature and liquidus temperature of the alloy T L , keeping warm for 5-15 min, and then rapidly water quenching to obtain semi-solid isothermal heat treatment sample. The preparation method can reduce residual stress of 4D printing forming sample, and prepare high-temperature high-entropy shape memory alloy with high density, few defects and high phase transition temperature.

The invention discloses a preparation method of an oligomeric silsesquioxane material modified moisture-curable polyurethane hot melt adhesive, and relates to the technical field of adhesives. The hot melt adhesive is prepared from the following raw materials in parts by weight: 10 to 30 parts of polyether polyol, 20 to 40 parts of polyester polyol, 10 to 20 parts of methacrylate copolymer resin, 1 to 5 parts of color paste, 5 to 15 parts of heptaisobutyltrisilanol-polyhedral oligomeric silsesquioxane, 15 to 25 parts of diphenylmethane diisocyanate and 0.1 to 0.5 part of a catalyst, the preparation process comprises the steps of vacuum dehydration of raw materials, secondary dehydration after addition of TPOSS, MDI reaction, addition of a catalyst, stirring, discharging and the like. The glass transition temperature, the high temperature resistance, the aging resistance and the corrosion resistance of the polyurethane hot melt adhesive are remarkably improved, meanwhile, the good body mechanical property and the bonding strength to different base materials are kept, and the polyurethane hot melt adhesive can be widely applied to bonding of key components in the consumer electronics industry, the intelligent wearing industry and the automotive electronics industry.

The invention relates to the technical field of polyether terminal chemical modification, and discloses high-frequency low-dielectric constant modified polyphenyl ether and a preparation process thereof, and the high-frequency low-dielectric constant modified polyphenyl ether is generated by carrying out nucleophilic substitution reaction on hydroxyl-terminated polyphenyl ether, 3, 5-di-tert-butyl salicyloyl chloride and an organic base catalyst in an aromatic hydrocarbon solvent; the method comprises the following steps of: introducing an asymmetric steric hindrance structure at the tail end of a molecular chain, physically locking a polarity center to turn polarization by utilizing a space exclusion volume, and performing self-limiting on the steric hindrance by adopting a mode of dropwise adding a modifier at a constant speed and monitoring a change slope of a hydroxyl conversion rate in combination with an infrared spectrum so as to trigger steric hindrance self-limiting termination. A local hydrophobic field generated at the moment of precipitation is utilized to induce generation of a nanoscale closed-pore cavity, dielectric loss eigen-frequency insensitivity is achieved, and the product has excellent dielectric stability and thermal mechanical rigidity and effectively blocks water molecule permeation.