35results about How to "Achieve controlled degradation" patented technology

The invention discloses melt-blown polypropylene as well as a preparation method and application thereof. The melt-blown polypropylene comprises following raw polypropylene resin, a degradation agent,an antioxidant and a lubricant, wherein the degradation agent is selected from one or more of hydrogen peroxide, sodium percarbonate, ammonium percarbonate and urea peroxide. The melt-blown polypropylene also comprises a nucleating agent selected from one or more of dibenzylidene sorbitol, aryl phosphate and nano scale amorphous silicon dioxide, wherein the degradation agent and the nucleating agent respectively account for 0.05-0.5% of the mass percentage of the raw materials. The preparation method comprises the following steps: premixing raw materials, stirring, then selectively adding a deodorant; and melting and granulating by an extruder to obtain the product. The invention also discloses an application of the melt-blown polypropylene in manufacturing melt-blown non-woven fabrics, melt-blown filter elements and sound-absorbing cotton. The melt-blown polypropylene has the advantages of low odor, high electret charge stability and the like.

The invention relates to a medical magnesium alloy surface mesoporous biological glass coating and a preparation method thereof. The composition of the coating is a 45S5 biological active glass (Na2O-CaO-SiO2-P2O5) system, wherein the mass ratio of the Na2O to CaO to SiO2 to P2O5 is 24.5:24.5:45:6.0; the coating has a mesoporous structure by adding a pore forming template agent. By using a sol-gel method and a dip-coating method, a sol coating containing the template agent is prepared on the surface of magnesium alloy, then gelation is performed, and thermal treatment is performed subsequently to discharge the template agent so as to finally obtain the mesoporous biological glass coating on the surface of the magnesium alloy. The process has a simple process and short production period; the obtained coating has good biological activity and degradability; the production of apatite and the cell adhesion are more facilitated due to the existence of mesopores; the structure of the mesoporous coating can be controlled by adjusting the conditions such as the content of the template agent, the thermal treatment temperature and the holding time, good interface bonding of the coating and a magnesium alloy substrate is realized, and the degradation performance of the magnesium alloy is adjusted and controlled.

The invention discloses a biodegradable barrier mulch film. The mulch film is prepared from a first melt and a second melt according to a mode of multi-layer co-extrusion and multi-layer co-blowing ora mode of multi-layered casting and two-way stretching, wherein the second melt forms a barrier layer film as an intermediate layer. The preparation process of the first melt is as follows: first resin, second resin, a complex stabilizer, an anti-blocking agent and an interface compatilizer are mixed and extruded in a screw extruder; and the preparation process of the second melt is as follows: barrier layer resin is extruded in situ through a screw extruder, and then the extruded barrier layer resin is directly mixed and extruded with first resin, second resin, a chemical stabilizer, an interface compatilizer and a composite inorganic salt buffering agent in a screw rod. The biodegradable barrier mulch film provided by the invention has high gas and water vapor barrier property, and improved water retention property; and in addition, through the in-situ reaction of the resin in processing, the weather resistance and biodegradability of the mulching film are balanced, the controllabledegradation of the mulching film is realized, and the mulching film has obvious advantages compared with conventional mulching film.

The invention provides a black phosphorus-based hydrogel near-infrared immune drug controlled-release system. The system comprises an agarose hydrogel carrier as well as black phosphorus nanosheets and anti-cancer immune drugs carried in the agarose hydrogel carrier. The black phosphorus-based hydrogel near-infrared immune drug controlled-release system has near-infrared response, and can realize transformation from a gel state to a sol state through near-infrared light irradiation, so that locally controllable drug release can be achieved, and tumor cells in focus positions can be effectively killed; the system has a controllable degradation characteristic, and has extremely high clinical value for cancer treatment. The invention also provides a preparation method of the black phosphorus-based hydrogel near-infrared immune drug controlled-release system.

The invention discloses a polylactic acid (PLA) composite material with a high degradation speed and a preparation method of the composite material. The composite material provided by the invention isprepared by adopting polylactic acid resin, PBAT resin, an inorganic filler, modified starch, an organic nucleating agent, a coupling agent, a chain extender, a compound photosensitive initiator, a thermal oxygen degradation initiator and a food-grade plasticizer, the heat resistance of the polylactic acid material is improved, and the use range of polylactic acid products is expanded; thermal degradation, photodegradation and hydrolysis speeds of wasted PLA products are increased, harsh conditions that require industrial composting are avoided, and the degradation speed faster than that of ordinary polylactic acid can be realized under natural conditions; the auxiliary agents used in the method are all food-grade raw materials and can be applied to food packaging; and the preparation method of the polylactic acid composite material with the high degradation speed provided by the invention employs simple equipment and is low in investment.

The invention provides a composite material, comprising a biodegradable material and GdPO4*H2O. As the composite material provided by the invention comprises the biodegradable material and the GdPO4*H2O, when an alternating magnetic field is applied to the obtained composite material serving as an implanted material, temperature of the composite material can be improved, and thereby degradation velocity of the composite material in a body is increased, and controllable degradation of the composite material in the body is achieved; meanwhile monitoring on variation of the composite material provided by the invention is achieved by nuclear magnetic developing, and thereby tracer monitor of the composite material in the body is achieved.

The invention discloses a starch based nanometer photocatalytic composite degrading modifying agent. The modifying agent is prepared by carrying out melt blending on the following raw materials, wherein the raw materials comprise, by weight, 72-87 parts of starch, 10-25 parts of polyvinyl alcohol, 10-20 parts of a small molecular plasticizer, 0.2-2 parts of a modified inorganic nanometer additive, and 0.5-1.5 parts of an antioxidant, wherein the modified inorganic nanometer additive is prepared by carrying out a surface lipophilic modification treatment on at least a material selected from anatase type nano-titanium dioxide, mixed crystal type nano-titanium dioxide and nano-cerium oxide through a silane coupling agent. The present invention further discloses a preparation method for the starch based nanometer photocatalytic composite degrading modifying agent. According to the present invention, the starch based nanometer photocatalytic composite degrading modifying agent of the present invention is adopted to modify the polymer material, such that the complete biodegradability can be achieved; the high content starch is added to the system, such that the cost of the final productcan be substantially reduced; with the added nanometer additive, it is ensured that the product has good physical and mechanical properties; the agent and the method of the present invention can be used for modifying preparations of various disposable plastic products, mulch films, supermarket plastic packaging bags, and the like.

The invention provides a controllably degradable high-strength magnesium-based composite scaffold coating and a preparation method thereof. The controllably degradable high-strength magnesium-based composite scaffold coating comprises a degradable magnesium alloy scaffold matrix, wherein the outer layer of the degradable magnesium alloy scaffold matrix is a high-strength zinc protective coating with biocompatibility; the average thickness of the high-strength zinc protective coating ranges from 5 to 40 [mu]m, the surface roughness Ra is smaller than 40 nm, and the water contact angle is smaller than 50 degrees. The specific preparation method comprises the steps that firstly, a laser cutting scaffold is subjected to an electrolytic polishing treatment, then a pretreated zinc layer is prepared, and finally the high-strength protective zinc layer is prepared through an electro-deposition process. The zinc protective coating prepared through the method is fine in tissue structure, uniform, compact and well combined with a matrix, and the mechanical strength and corrosion resistance of the magnesium alloy scaffold can be remarkably improved. The high-strength zinc protective coating shows good hydrophilicity and is very beneficial to improving the cell compatibility and the blood compatibility of a magnesium alloy intravascular scaffold.

The invention provides a recombinant spider silk protein. The sequence structure comprises at least two spider silk protein structural domain monomers and at least one protease enzyme digestion site;each protease enzyme digestion site is positioned between every two adjacent spider silk protein structural domain monomers. By inserting each protease enzyme digestion site between every two adjacentspider silk protein domain monomers, when the recombinant spider silk protein is used in vitro, the recombinant spider silk protein can be combined with a tool enzyme to control the enzymolysis of the recombinant spider silk protein. Compared with existing spider silk proteins which need to be slowly degraded for a long time under the assistance of microorganisms, the recombinant spider silk protein has the advantage of controllable degradation; when the recombinant spider silk protein is used in the human body, since the protease enzyme digestion sites on the recombinant spider silk proteincan be enzymatically hydrolyzed by enzymes in the human body, a biological material prepared from the recombinant spider silk protein can be slowly degraded in the human body, so that the applicationvalue of the recombinant spider silk protein is increased, and the application is wider.

The invention belongs to the field of cycle utilization and recycling of waste high-molecular materials, and particularly relates to a method for preparing terephthalic acid and p-phenylenediamine bydegrading p-aramid fibers. The technical problem of recycling of p-aramid fibers is mainly solved. Amide bonds are selectively broken through metal ion coordination catalysis, and an exchange reactionof an organic carboxylic acid and the amide bonds is used to controllably degrade the p-aramid fibers in order to obtain terephthalic acid and a p-phenylenediamine acyl derivative. Terephthalic acidcan be separated firstly by utilizing the characteristics of water solubility and acidification precipitation of terephthalate; and then the p-phenylenediamine acyl derivative undergoes an alcoholysisreaction by using a strong base as a catalyst, and the p-phenylenediamine is precipitated through cooling crystallization. The method achieves controllable chemical degradation of the p-aramid fibersand recovery and preparation of the monomers terephthalic acid and p-phenylenediamine.

The invention relates to the technical field of oil and gas well development, and concretely relates to a degradable self-plugging-removal temporary plugging agent for water-based solid-free reservoir drilling fluid suitable for oil and gas well drilling, and a preparation method thereof The degradable self-plugging-removal temporary plugging agent for the reservoir drilling fluid is a blend of a biodegradable polymer temporary plugging material and acid-soluble temporary plugging particles. Practice proves that acidification degradation can be generated within a period of time after well completion, the temporary plugging rate of the temporary plugging agent is greater than or equal to 98%, the plugging removal rate is greater than or equal to 99%, and the reservoir core permeability recovery value is greater than or equal to 95%; meanwhile, the temporary plugging agent disclosed by the invention has a self-plugging-removal capability, self-plugging removal can be realized by hydrating and decomposing a self-generated acid solution through a biological degradable material during later reverse drainage, the processes of removing mud cakes through acid pickling and the like are not needed, secondary damage to a reservoir is avoided, and the temporary plugging agent is a simple, convenient, efficient and side-effect-free temporary plugging technology.

The invention belongs to the field of recycling of waste high polymer materials, and particularly relates to a method for recovering polyimide by selectively breaking imide bonds. The method comprises the following steps: preparing a reaction system by using polyimide waste, a solvent and a catalyst, and placing the reaction system in a homogeneous reactor for degradation reaction; filtering after degradation is completed, and adding deionized water to wash a filter cake to obtain aromatic diamine; and evaporating out the solvent in the filtrate, and adding hydrochloric acid to obtain aromatic phthalic acid. According to the invention, the imide bonds are selectively broken by using a basic catalyst to obtain the aromatic diamine and the aromatic pyromellitic acid. The method has the advantages of simple operation process, low recovery cost and easiness in separation to obtain high-added-value products.

The invention discloses a method for chemically preparing a pectin oligosaccharide having a molecular weight of 2000-3000 Da. The method comprises the following steps: regulating the pH value of a pectin solution to 9.5-10.5, adding H2O2, and reacting; then regulating the pH value of the reaction solution to be slightly lower than the initial pH value; and finally, adding ethanol to precipitate, washing the precipitate, and drying. According to the invention, the controllable degradation of pectin is realized, and the pectin oligosaccharide having a weight average molecular weight of 2000-3000 Da is prepared, thereby improving the product quality; and tests prove that the pectin oligosaccharide has a better antibacterial activity.