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

The invention discloses an enzymolysis-modified sargassum horneri polysaccharide and an application thereof. A preparation method of the enzymolysis-modified sargassum horneri polysaccharide comprises steps as follows: (1) performing microwave extraction on a sargassum horneri polysaccharide to obtain a coarse polysaccharide extract; (2) performing grading alcohol precipitation: performing precipitation on the coarse polysaccharide extract with the final ethanol volume fraction of 30-40% and 55-65% successively to obtain an SHP60 coarse polysaccharide component; (3) performing decolorization and deproteinization on the SHP60 coarse polysaccharide component to obtain an SHPA polysaccharide; (4) performing enzymolysis on the SHPA polysaccharide with a dextranase to obtain an enzymatic product; (5) performing ion column chromatography on the enzymatic product with a DEAE-Sepharose Fast Flow ion column chromatography system, and concentrating and filtering an eluent to obtain a filtrate; (6) performing gel column chromatography on the filtrate obtained in Step (5) with a Sephadex G-25 gel chromatography system, collecting a salt-free polysaccharide part, and performing concentration and freeze-drying to obtain the enzymolysis-modified sargassum horneri polysaccharide. The enzymolysis-modified sargassum horneri polysaccharide can be applied to preparation of an antioxidant, a moisture absorbent and a moisturizer.

The present invention provides a controllable degradation and recovery method of polyurethane. The method is characterized in that controllable degradation of waste polyurethane is carried out in an eutectic solvent, and the obtained degradation products are separated and purified to obtain a polymer polyol and an amine. The method avoids pollution of burying and burning to soil, water and air, avoids the defect that only chemicals with low added values can be obtained by physical crushing, and also avoids the harms of toxic gases generated by heat treatment. A degradation system used in the method is the eutectic solvent, the controllable degradation can be achieved by selectively breaking bonds of polyurethane without adding other catalysts, the preparation method and the use process ofthe degradation system are green, environmentally friendly, economical and saving, and can be recycled, and the degradation products obtained by the method are easy to separate, and are convenient torecover.

The invention discloses a suspending skin tissue engineering nanofiber support and a preparation method of the suspending skin tissue engineering nanofiber support. The support is composed of a polylactic acid-glycolic acid copolymer nanofiber membrane and a polypropylene auxiliary strut, wherein the nanofiber membrane is prepared through an electrospinning technology, through control over process parameters and using of different receiving devices, different structures with orderly or unordered fiber arrays are obtained, and the structures are adhered together through heating and the auxiliary strut. The obtained nanofiber support can suspend on the surface of a culture solution, keep straight performance and integrity for a long time and simulate the growing environment of skin cells and is beneficial to adherency, growth, migration, multiplication and differentiation of the skin cells, and finally the tissue engineering dermis is formed. The suspending skin tissue engineering nanofiber support and the preparation method are simple in preparation technology, low in cost and easy to apply widely.

The invention relates to the technical field of biomedical materials, in particular to a controllably degradable bone implantation composite material and a preparation method thereof. The bone implantation composite material comprises a nano bioglass material as a main structure, an amino acid polymer, and a modified calcium carbonate whisker / natural latex compound as a synergistic component, wherein graphene is added into the modified calcium carbonate whisker / natural latex compound serving as the synergistic component. According to the preparation method, the raw materials of the bone implantation composite material have good biological activity and biocompatibility, interaction between tissues and cells and the material is facilitated, the composite material has enough mechanical strength, meanwhile, the composite material can be rapidly degraded in the later period, the degradation rate of the bone implantation composite material can be adjusted by changing components, and the controllable degradation of the bone implantation composite material is realized.

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.