212results about How to "Increase the relative molecular mass" patented technology

The invention discloses a method for preparing a high-performance flame-retardant PLA (polylactic acid) / graphene nano-sheet composite material. The composite material comprises the following components in parts by weight: 30-100 parts of PLA, 10-30 parts of flame retardant, 5-10 parts of a flame retardant synergist, 1-5 parts of a nucleation accelerant, 2-6 parts of a flexibilizer, 1-6 parts of a graphene nano-sheet, 5-15 parts of carbon fibers, 10-20 parts of glass fiber, and 5-25 parts of talc powder. According to the preparation method, the mechanical performance of PLC can be improved by adopting the graphene nano-sheet which is subjected to surface treatment by a silane coupling agent. The composite material has the advantages that the compatibility of the graphene nano-sheet and PLA can be improved, the graphene nano-sheet can be well dispersed in matrix resin to play the effect of synergetic flame retardance.

The invention discloses a triggering method of acrylamide through two-segment composite low-temperature and high-temperature system, which comprises the following steps: adding acrylamide monomer into water with density at 20-40% without removing oxygen; cooling to 0 deg.c; adding oxidant-reducer-catalyst and azo-compound into composite system; sealing the reactor; insulating to react for 4-6h to finish polymerizing; fetching gel-shaped material; purifying through anhydrous alcohol; drying in the vacuum under 50-60 deg.c to constant weight; obtaining the product with molecule at 20000000-28000000; simplifying the reaction without removing oxygen.

The invention discloses a prodrug system prepared by connecting a series of oligopolymers synthesized by a group protection and deprotection method and polyethyleneglycol to be used as a drug carrier, belonging to the technical field of chemical drugs. Laden drugs are water-insoluble anti-tumor drugs such as taxol, or other cancer therapy drugs such as doxorubicine and camptothecin. A research discovers that drug compositions prepared by the method greatly improve the hydrophobic nature of the anti-tumor drugs and can accurately control the gather time of the oligopolymers on focus parts and the hydrolyzation rupture time of ester bonds by accurately controlling the lengths of segmers of the oligopolymers so as to control the drug release time so that drugs are stably released, thereby the method prevents burst release causing toxic side effect on normal cells, reduces the drug dosage to enhance the curative effect and sufficiently plays a sustained and controlled release role; and in addition, the structure of the oligopolymers is accurate, and the molecular weight of synthesized amphipathic block polymers which are uniformly distributed is accurate, thereby the method can ensure synthesized drug ingredients to be definite and stable and the pharmacokinetics and the treatment effect (activity and toxicity) of the synthesized drugs to have good reproduction quality and be accurately defined.

The invention relates to a pressure sensitive adhesive tape for high-temperature resistant masking and a preparation method thereof. The pressure sensitive adhesive tape consists of a substrate layer, an isolator layer, a release agent layer, a primer layer and an adhesive layer, wherein the isolator layer and the release agent layer sequentially cover the upper surface of the substrate layer, and the primer layer and the adhesive layer sequentially cover the lower surface of the substrate layer. The pressure sensitive adhesive tape prepared by the invention, compared with the prior art, can avoid crack and residue when being peeled off after being roasted for 60 minutes at high temperature of 180 DEG C, and the adhesive property has strong adhesive property and can avoid a wrapping phenomenon when being used.

The invention discloses a preparation method of ternary copolymerized cationic polyacrylamide, including the following steps: stirring to dissolve cationic monomer diallyl dimethyl ammonium chloride,methacrylamide, propyl trimethylammonium chloride, nonionic monomer acrylamide, a metal ion chelating agent, and a chaotropic agent in water, adding a chain transfer agent and an initiating agent in turn after injecting nitrogen for removing oxygen, which evenly mixes the chain transfer agent and initiating agent and reaction liquid by effect of the nitrogen flow to obtain the ternary copolymerized cationic polyacrylamide colloid product, obtaining the colloidal particles by prilling the colloid product, adding anti-crosslinking agent solution into the colloidal particles for mixing, drying and milling the colloidal particles into powder, after sieving, obtaining powder product of the ternary copolymerized cationic polyacrylamide. The ternary copolymerized cationic polyacrylamide has significant hydrolysis resistance property, flocculent property is maintained and improved, the product economy is optimized relative to copolymerized products of MAPTAC and acrylamide. The method is applicable to large kettle production, which is easy to implement industrialization.

The invention discloses synthetic-leather-used UV solidifying and flame-retarding polyurethane and a preparation method thereof. The method is characterized by comprising the steps that low-viscosity liquid dihydric alcohol and diisocyanate serve as raw materials, side-group phosphorus / nitrogen-containing dihidroxy acrylate is introduced into the polyurethane structure in the form of chain extender, and then side-group phosphorus-containing monohydroxy acrylate is used for sealing the end. Both a main chain and a side chain of the obtained UV solidifying polyurethane contain photosensitive perssad, through the UV solidification, the crosslinking degree and relative molecular mass of resin can be improved, the contradiction between the fact that photosensitive perssad in traditional UV solidifying polyurethane is low in content and the fact that the molecular weight of coating polymer is high in requirement is reconciled, and meanwhile the comprehensive performance of the polyurethane such as wear resistance, scratch resistance, waterproofness, heat resistance and solvent resistance is improved; phosphorus / nitrogen flame-retarding ingredients are 'suspended'on the macromolecular side chain of the polyurethane, the flame-retarding effect is good, and fire retardant is not migrated or separated out and is resistant to hydrolysis in the storage and using processes; in addition, no organic solvent is used in the preparation process of the polyurethane, and the synthetic-leather-used UV solidifying and flame-retarding polyurethane has the advantages of being prominent in greenness, environment-friendliness, health, safety and the like and can be used in synthetic leather manufacturing and coating materials such as leather and textiles.

A process for preparing the chitin or chitosan with high relative molecular mass is characterized by that EDTA instead of HCl is used for decalficiation, resulting in no damage to molecular chain and higher yield increased by 10% or more. Its by-products and rejected substance are all recovered for lower cost.

The invention belongs to the technical field of plant component extraction, and discloses a method for extracting pectin from waste sisal residues. The method includes the steps of smashing sisal residues, killing enzyme with hot water, conducting extracting through a cellulose compound enzyme solution after degreasing to obtain a sisal residue pectin solution extracted through an enzyme method and solid residues, adding solid residues to an ammonium oxalate solution, conducting ultrasonic extracting to obtain a sisal residue pectin solution extracted through an ultrasonic method, combining and concentrating the sisal residue pectin solution, adding absolute ethyl alcohol for sedimentation, and making sediment sequentially subjected to decoloring through an acid alcohol solution and washing through an ethyl alcohol water solution and vacuum drying to obtain sisal residue pectin. The enzyme method and the ultrasonic extracting method are put forward first so that sisal residue pectin can be extracted; compared with an acid extracting method, an oxalic acid and ammonium oxalate extracting method, a fermentation method and the like in the prior art, the pectin extracting rate is increased to be 30-40% from 10-15%.

The invention relates to a synthetic method of anionic polyacrylamide, which comprises the steps of adding distilled water, an acrylamide monomer, an acrylic monomer and sodium hydroxide powder to a reaction device in sequence, stirring uniformly until completely dissolving to form a monomer aqueous solution, adding appropriate solubilizer, chelating agent and initiator to the monomer aqueous solution, stirring uniformly, filling high-purity nitrogen into the reaction device, exhausting air in the reaction device, sealing the reaction device, placing in an ultraviolet light reaction device, initiating a polymerization reaction under the irradiation of ultraviolet light with certain wavelength, generating an anionic polyacrylamide colloid, purifying, washing and refining the colloid, drying in a vacuum drying oven, grinding, and obtaining anionic polyacrylamide. The method is simple in process, short in production cycle and few in procedure; the polymerization reaction is more stable, and easy to control; prepared polyacrylamide is large in molecular weight, high in conversion rate and solid content, good in dissolvability, and stable; and anionic polyacrylamide is high in DEHP (Di-2-Ethyl Hexyl Phthalate) removal rate.

The invention relates to a biodegradable aliphatic-aromatic block mixed polyester preparation method, and belongs to the technical field of mixed polyesters. The preparation method comprises that: dimethyl terephthalate and excess aliphatic diol are subjected to ester exchange to obtain a poly terephthalate diester oligomer having terminal hydroxyl, the poly terephthalate diester oligomer having the terminal hydroxyl reacts with an aliphatic dicarboxylic acid to obtain an aliphatic-aromatic block mixed polyester prepolymer, and chain extenders such as diacyl di-lactam and bisoxazoline are adopted to carry out chain extension to prepare the biodegradable aliphatic-aromatic block mixed polyester with the 30 DEG C intrinsic viscosity of 0.48-0.78 dL / g. According to the method, the polymerization temperature is moderate and is 180-240 DEG C so as to avoid side reaction intensifying at the later stage of the high temperature reaction, and the obtained polymer has characteristics of high melting point, excellent thermal stability and excellent mechanical property.

The invention discloses a composting method used for increasing humic acid content through phased adding of humic acid precusor substances. The composting method is used for solving a problem in the prior art that humic acid content is not high. The composting method comprises following steps: 1, protein organic waste and fiber organic waste are subjected to composting, at composting temperature increasing period, MnO2 is added, and a low concentration polyphenol waste is added; 2, before composting high temperature period, in each time of overturning of the protein organic waste, a sugar containing waste, a polyphenol waste, and a carboxyl waste are added, in each time of overturning of the fiber organic waste, the protein organic waste and the carboxyl waste are added; 3, at composting high temperature period, a humic acid containing precursor waste is packaged with textile bags, and is embedded in high temperature period compost; and 4, at composting temperature reduction period, ahumic acid containing precursor waste processed through harmless treatment is added into compost for at least one time. The composting method is used in the field of composting.

The invention relates to creep-resistant polyester and its preparation method. According to the preparation method, polyester is mixed with a fluorine-containing epoxy compound or a fluorine-containing epoxy compound is added during the synthesis process of polyester. Then, the creep-resistant polyester can be obtained. By the use of the fluorine-containing epoxy compound for blocking modification of the polyester, creep-resistant performance of the polyester can be improved to some extent, and hydrolysis resistance and performance stability of the polyester can be raised. Fiber prepared from the creep-resistant polyester can be used in a hot and humid environment for a long time, and has a huge prospect in the fields of plastic packing, waterproof fabric, ropes, cables, marine fiber and the like.