243results about How to "Shorten degradation time" patented technology

A method for extending the gelation time of an oxidized polysaccharide to react with a water-dispersible, multi-arm amine to form a hydrogel is disclosed. The extension of the gelation time is accomplished by using a chemical additive. The method also extends the time for the hydrogel to become tack-free, and may also be used to decrease the degradation time of the hydrogel. The chemical additive reacts with the functional groups of the oxidized polysaccharide or the water-dispersible, multi-arm amine, thereby reducing the number of groups available for crosslinking. The use of the resulting hydrogel for medical and veterinary applications is described.

The invention relates to an efficient straw degrading composite fungicide (JFB-1) and an organic fertilizer preparing method thereof. The composite fungicide comprises composite bacteria and a carrier, wherein the carrier is wheat bran, and the composite bacteria include composite bacteria I, composite bacteria II, composite bacteria III and auxiliary bacteria. The composite bacteria I, II and III account for 1-1.5% of the weight of straws, wherein the composite bacteria I account for 20-25%, the composite bacteria II account for 45-50%, the composite bacteria III account for 30-35%, and the composite bacteria are added uniformly in compost fermentation so as to effectively improve the maturation speed and the quality of an organic fertilizer. The fungicide is fully mixed with straws of rice, asparagus and other crops to carry out compost fermentation, the straws can be degraded rapidly through the synergistic effect of the bacteria, the degradation efficiency is improved, the degradation time is shortened, and insect pests are effectively killed and are rapidly transformed into the organic fertilizer for improving soil. The efficient straw degrading composite fungicide can be used for effectively solving the problem of land occupation caused by landfill, or the problems of fire, traffic dangers, environment pollution and the like caused by burning.

A rare earth-doped Ti-base SnO2 electrocatalytic electrode relates to one type of DSA electrode and its preparing process. The rare earth-doped electrode in this invention is composed of the Titanium substrate and the rare earth-doped SnO2 coat in which the mol ratio of Sn, rare earth elements and Sb is 75-99.8:0.1-10:0.1-15. In this process the Titanium electrode is polished, washed with alkaline and acid, then undergoes delaminated impregnation and gradient temperature rise to realize the formation of the functionally gradient membrane that endows the electrode with relatively high potential of oxygen evolution, strong degrading ability of organic compounds and inert composition without dissolving out. The electrode has strong degrading ability especially of the materials persistent to biodegration or toxic to organisms.

The invention discloses a mixed bacterial agent capable of degrading antibiotics in soil, belonging to the field of microbial technology. The mixed bacterial agent is prepared by mixing Bacillus subtilis J5P2 and Pseudomonas J2 according to a volume ratio of (0.1-3): 1. A preparation method for the mixed bacterial agent comprises the following steps: I, preparation of a suspension; II, colony culture: (1) preparation of a medium and (2) culture; III, separation of strains; IV, subculture and domestication: (1) domestication, (2) preparation of a LB medium, and (3) preservation; V, preparation of inoculum liquid; and VI, preparation of the mixed bacterial agent. The mixed bacterial agent provided by the invention has the characteristics of capacity of effectively degrading a plurality of residual antibiotics in soil and reducing environmental pollution, etc., and can be used for the remediation of land contaminated by antibiotics such as tetracycline, penicillin, sulfadiazines and quinolones.

The invention discloses an enzyme-bacterium duplex straw decomposing agent and its preparation and application methods. The decomposing agent is made by mixing a composite microbial agent and a composite enzyme agent in a weight ratio of 3-4:1. The composite microbial agent includes Trichoderma viride, Aspergillus niger, Aspergillus oryzae, Brevibacillus laterosporus and a fused Saccharomyces cerevisiae, having a weight ratio of (1-2):(1-2):(1-2):(2-3):(2-3). The composite enzyme agent includes cellulase produced by the fermentation of Trichoderma reesei, hemicellulase produced by the fermentation of Bacillus subtilis, and ligninase produced by the fermentation of Pleurotus ostreatus, having a weight ratio of (1-2):(1-2):(1-2). The decomposing agent has a double straw degrading function, allowing more efficient and more thorough biological degradation, increasing the straw degrading speed to a higher extent and shortening degrading time, and can fully decompose crop straw to fields within about a week, without affecting the planting and transplanting of next-stubble crops.

The invention discloses a high-compatibility starch-based full-biodegradable resin. The high-compatibility starch-based full-biodegradable resin is prepared from, by weight, 30 to 60 parts of plant starch, 1 to 10 parts of a reaction auxiliary agent, 40 to 70 parts of a polyester resin, 2 to 5 parts of a plasticizer, and 0.2 to 1 part of a mould releasing agent. The invention also relates to a preparation method of the high-compatibility starch-based full-biodegradable resin. The high-compatibility starch-based full-biodegradable resin is high in starch content, and excellent in material compatibility and mechanical properties, and is suitable for plastic processing technology such as blow molding and film blowing; full biodegradation of the high-compatibility starch-based full-biodegradable resin can be realized; product surface is smooth; dispersion is uniform; light transmittance is high; and mechanical strength is capable of satisfying related requirements.

The invention discloses a zinc coordination polymer as well as a preparation method and application thereof. According to the method, under a solvothermal condition, a zinc complex is prepared firstly, and then is doped with a small amount of cobalt ions, so that a doped complex is obtained. Compared with conventional method, the method disclosed by the invention has the advantages that a zinc complex catalyst doped with the small amount of cobalt ions is better in the reaction effect of catalyzing and light-degrading Rhodamine B, can realize recycling, and keep relatively high catalytic efficiency.

The invention discloses a degradable plastic film and a preparation method thereof. The degradable plastic film is prepared from the following raw materials: 47-62 parts of thermoplastic polyurethaneresin, 10-25 parts of modified polylactic resin, 7-15 parts of polyvinyl alcohol, 7-10 parts of a plasticizer, 5-8 parts of inorganic filler, 5-8 parts of maltodextrin, 2-5 parts of chitosan oligosaccharide and 2-5 parts of lignocelluloses. The preparation method includes: adding the raw materials into a high-speed mixer for uniform mixing, then performing extrusion and granulation by a single screw extruder, and then conducting blowing molding or tape casting, thus obtaining the degradable plastic film. The degradable plastic film obtained by the invention is completely biodegradable and pollution-free, can achieve a degradation rate of 98% within 3-4 months, has the characteristics of excellent toughness, wear resistance, mechanical properties and thermoplastic processing properties, safety and environmental protection.

The invention discloses a biodegradable bionic fishing bait material and a preparation method thereof and relates to the technical field of artificial fishing baits. A main raw material of the biodegradable bionic fishing bait material is a blend of two or a plurality of types of degradable thermoplastic materials, such as polyurethane (TPU), polyhydroxyalkanoate (PHA), polylactic acid (PLA), polyhydroxypropionic acid-glycolide (PLGA) and capryl glycol polycitrate (POC); an environment-friendly plasticizer is one or more of a compound of citrate, isosorbide, epoxidized soybean oil and the like; feeding characteristics of fish varieties are matched with a plurality of types of fish attracting components including corn starch, a plurality of types of amino acids, minerals, protein and the like, and an antioxidant for a bionic fishing bait, and the components are blended and granulated; a mixture is subjected to injection molding to obtain the bionic fishing bait with various colors and fish, shrimp and insect shapes. The bionic fishing bait prepared by the invention has advantages of a food fishing bait and the bionic fishing bait, and has a great attraction force on the taste senseof fishes; a product is adjustable in hardness and can be completely biodegraded, and is an ecological environment-friendly bionic fishing bait for attracting the fishes.

The invention relates to a preparation method and a refining method of medical hemostatic polysaccharide starch. With pretreated potato starch as a raw material and epichlorohydrin as a crosslinking agent, a microsphere adopting a three-dimensional network structure is synthesized by an emulsifying and crosslinking technology. The medical hemostatic polysaccharide starch is high in biocompatibility; the medical hemostatic polysaccharide starch is full with wrinkles on the surface, so that the particle surface area is increased, the water absorbing rate is significantly improved and the hemostatic time is greatly reduced; the medical hemostatic polysaccharide starch is especially applicable to large-area blood seepage, deep bleeding, and bleeding at a part difficult to reach by operative procedures.

The invention provides a magnesium alloy support coated with an acylated chitosan and polyester blend medicine coating. The support comprises a magnesium alloy bare support, the magnesium alloy bare support comprises at least two annular units formed by cylindrical rods in a sine 'peak-valley' shape, the annular units are connected on the axial direction through a link round rod to form a net structure, a blend medicine eluting type coating composed of acylated chitosan, polyester and medicine is coated on the surface of the magnesium alloy bare support. According to the invention, biological medical chitosan and polyester blend material are taken as a support surface coating to improve the biological compatibility, and the coating carries a medicine with restenosis resistance function, thereby the release speed of the medicine can be controlled, and the treatment purpose can be achieved. The magnesium alloy support coated with the acylated chitosan and polyester blend medicine coating possesses good collateral passing ability and flexibility, good radial supporting performance, and is capable of keeping perfusion smoothness of blood flow, effectively delaying the degradation time of the magnesium alloy support, controlling the release of the medicines, and reducing the incidence rate of acute and subacute thrombus after the support is implanted.

The invention relates to compound microbial decomposed inoculas, and a preparation method and an application thereof. Effective components of the involved compound microbial decomposing inocula comprise bacillus amyloliquefaciens Ba168, paenibacillus peoriae BC-39, trichoderma harzianum, candida krusei, aspergillus niger and streptomyces griseus. The preparation method comprises that each strain are fermented separately, and the strains are mixed for use according to the proportion after the completion of the fermentation. The involved application is an application of the compound microbial decomposing inocula in degradation of crop straw. The compound microbial decomposing inocula not only give full play to unique degradation function of the bacillus on the straw, are combined with microbial compound flora for efficient synergy in the straw degradation process, thereby efficiently and rapidly degrading the straw, and significantly enhancing soil organic matter and humus levels.

The invention discloses a degradable type composite filter rod for cigarette and a preparation method thereof. The preparation method comprises the following steps: edible raw materials such as grain, tubers, pulses or starchy are cut and smashed into uniform particles; 65-90% of cut and smashed raw materials are fully mixed with 3-30% of cyclodextrin and 5-15% of gelatin; 80-90 DEG C water with a weight of 10-30% of the total weight of the mixture are added, and a puffed material is obtained after stirring and mixing for 20-30 min; the puffed material are extruded and formed to obtain a puffed filter of a cigarette; a composite filter rod for cigarette is obtained by using the puffed filter and convention cellulose acetate fibers. According to the invention, the degradable type composite filter rod allows a cigarette filter to be novel and variable in structure without changing the physical property and the smoking quality of a cigarette, and is safe, nontoxic and environment-friendly; the degradation time of the degradable type composite filter rod is shortened; the environmental pollution is reduced.

The invention discloses a preparation method of petroleum-degrading acinetobacter junii bacillus, relates to a preparation method of a petroleum-degrading bacterial agent, and is used for solving the problems that transportation and storage are inconvenient due to the fact that the petroleum is directly degraded by using the bacterial fermentation liquor, the injuries to human bodies are relatively large, and a traditional microbial agent is low in cost. The method comprises the following steps: 1, selecting acinetobacter junii, inoculating into a culture medium, and cultivating to obtain a first-stage seed solution; 2, adding the first-stage seed solution into a fermentation culture medium, and cultivating to obtain a bacterial fermentation liquor; and 3, sterilizing corncob powder, rice bran and wheat bran, mixing any two of the corncob powder, the rice bran and the wheat bran, adding the bacterial fermentation liquor, sodium chloride and monopotassium phosphate to the mixture, mixing evenly, baking, and hermetically storing, so as to obtain the petroleum-degrading acinetobacter junii bacillus. The petroleum-degrading acinetobacter junii bacillus has the advantages of being low in price, easy to degrade, and free of secondary pollution; meanwhile, the soil fertility can be improved; and the method is applied to degradation of petroleum.

A graphitic carbon nitride / silver carbonate / silver bromide ternary composite nano-material, a preparing method thereof and uses of the nano-material are disclosed. Rodlike Ag<2>CO3 and g-C3N4 having a lamellar structure grow together, and AgBr particles are attached to the surface of the Ag<2>CO3. The nano-material comprises 5-30 wt% of the g-C3N4 and 1-8 wt% of the AgBr, with the balance being the Ag<2>CO3. The preparing method includes (1) subjecting urea and melamine to high-temperature solid-phase sintering to obtain a g-C3N4 lamellar structure, (2) synthesizing the g-C3N4 nanosheet, a soluble silver salt and a carbonate or bicarbonate into g-C3N4 / Ag<2>CO3 particles through a solution precipitation reaction, and (3) introducing Br<-> to the g-C3N4 / Ag<2>CO3 particles. The prepared ternary composite nano-material is high in yield and can be adopted as a photocatalyst.

The invention discloses an organic garbage decomposing bacterium agent, as well as a preparation method and an application of the organic garbage decomposing bacterium agent. The bacterium agent is composed of 55-60% by weight of I compound bacterium agent and 40-45% by weight of II compound bacterium agent, wherein the I compound bacterium agent as well as the II compound bacterium agent are composed of bacterium liquid and a carrier, and respectively adsorbed on the carrier by the bacterium liquid; and the ratio of the bacterium liquid to the carrier is 2-3 hundred million bacteria to per gram of the carrier. The organic garbage decomposing bacterium agent is uniformly added according to 0.5-1% of the weight of an organic garbage heap; and the synergistic effect of various bacteria is capable of effectively accelerating the decomposition speed of the organic garbage and improving the quality of produced organic fertilizer. Due to use of the organic garbage decomposing bacterium agent, the pollution problems such as wastewater overflow, odor smell and mosquitoes flying around caused by the organic garbage stacking are effectively solved, and high-quality organic fertilizer can be produced.

The invention relates to an efficient wheat straw degradation composite bacteria organic fertilizer. The efficient wheat straw degradation composite bacteria organic fertilizer is formed by fermenting wheat straw minces with efficient wheat straw degradation composite bacteria, wherein, the efficient wheat straw degradation composite bacteria are composed of a carrier and a compound bacterial agent, the carrier is corn cob powder, and the compound bacterial agent is composed of a bacterial agent I and a bacterial agent II; and the compound bacterial agent is fully mixed with wheat straw substances in an aerobic fermentation device, and wheat straws are degraded through synergistic effect of different strains, thus the degradation efficiency is improved and the degradation time is shortened, and the substances can be rapidly decomposed and recycled and then are converted into the fertilizer capable of improving soil. By utilizing the efficient wheat straw degradation bacterial agent, the problems such as land occupation caused by landfill or fire hazard, traffic hazard, environmental pollution and the like caused by incineration can be effectively solved.

The invention discloses a microwave-assisted xylooligosaccharide preparation method. The method comprises the steps of: a. extracting polyxylose from wood fiber raw material with an alkaline process; b. adding the polyxylose obtained from the step a into 0.1-0.4M acid, degrading for 10-90min at the temperature condition of 70-100 DEG C and treating by using microwave with power of 500-800W at the same time, wherein the massic volume (g / ml) of the polyxylose to the acid is 1:20-100; c. centrifuging or filtering for separating the degradation liquid obtainedin the step b, and neutralizing the supernate or filtrate; and d. carrying out freeze drying or vacuum drying on the neutralized supernate or filtrate to obtain xylooligosaccharide. The method is fast, high-efficiency, generates few side effects, and the purity of the prepared xylooligosaccharide is high.

The microwave polysaccharide degrading process includes compounding polysaccharide solution of 5-150 g / L concentration and adding acid in concentration of 0.1-2.5 mol / L; setting the solution inside microwave generator and regulating power to 50-300 W to degrade at 10-90 deg.c for 1-30 min; and neutralizing pH to 7 with alkali, dialyzing to eliminate generated small molecular salt and freeze drying to obtain polysaccharide oligomer. The polysaccharide is originated from plant, animal and microbe and has numerically average molecular weight of 5-2000 KDa. The present invention has simple technological process, low cost and less pollution. The said technological process makes it possible to obtain various polysaccharide in specific molecular weight section and with greatly raised clinical bioavailability.

The invention discloses a bismuth / bismuth vanadate composite photocatalyst and a preparation method and application thereof to photocatalytic degradation of organics. The bismuth / bismuth vanadate composite photocatalyst is formed by in-situ growth of nano bismuth particles on surfaces of bismuth vanadate particles. The preparation method includes: mixing vanadium source containing aqueous solution and bismuth source containing ethylene glycol solution, and performing solvothermal reaction to obtain bismuth vanadate; dispersing the bismuth vanadate into water to obtain bismuth vanadate dispersion liquid; mixing the bismuth vanadate dispersion liquid with reductant solution, and performing hydrothermal reaction to obtain the bismuth / bismuth vanadate composite photocatalyst wide in light absorption range, high in visible light utilization rate and high in photocatalytic activity. Compared with bismuth vanadate catalysts, the bismuth / bismuth vanadate composite photocatalyst has the advantage of high catalytic activity in photocatalytic degradation of the organics. In addition, a synthesis method of the bismuth / bismuth vanadate composite photocatalyst is simple, raw materials are cheap and easy to acquire, and production cost is low.

The invention discloses a TiO2 nano-beam / boron-doped diamond film composite photoelectrocatalysis electrode and a preparation method and application thereof and belongs to the technical field of materials chemistry, environmental electrochemistry and pollutant control. The preparation method of the TiO2 nano-beam / boron-doped diamond film composite photoelectrocatalysis electrode comprises the steps that firstly, a layer of boron-doped diamond film which has the good electrochemical performance is deposited on a silicon substrate through a microwave plasma chemical vapor deposition method; secondly, TiO2 nano-beams which have the photocatalytic performance are grown on the surface of the boron-doped diamond film through a hydrothermal method; and finally, the composite photoelectrocatalysis electrode of a p-n junction structure is formed. Compared with a boron-doped diamond film bare electrode, the TiO2 nano-beams of the composite photoelectrocatalysis electrode are added for modification, so that the p-n junction structure is formed, and accordingly the photoelectric conversion efficiency is improved, and the degrading time of organic dyestuff in waste water is effectively shortened; compared with an electrode modified through a TiO2 nano-film, the electrode has more active sites, the contact area between the electrode and the dyestuff can be increased, and the degrading efficiency is improved.

The invention discloses a degradable injection grade bamboo-plastic composite material, which comprises the following components in part by weight: 35 to 45 parts of bamboo powder, 50 to 70 parts of thermoplastic plastic, 1 to 5 parts of coupling agent and 1 to 5 parts of lubricant. The thermoplastic plastic is PE and PP; the lubricant is stearic acid; and the coupling agent is maleic anhydride grafted PE, PP, silane or titanium ester. The preparation method comprises the following steps of: crushing plastic particles into particles with the diameter of between 0.1 and 0.7 centimeters and crushing wood fiber to 40 to 120 meshes; sequentially adding the plastic, wood powder, the lubricant, the coupling agent and the like into a high speed mixer to obtain a premix; and pelletizing the premix by a double-screw extruder and controlling temperature within a certain range to obtain injection grade bamboo-plastic particles. The invention provides the degradable injection grade bamboo-plastic composite material which has high bamboo powder content, is environment-friendly, and is easy to degrade.

The invention discloses an energy-saving microbial mobile toilet and a manufacturing method thereof. The mobile toilet comprises an outer frame, a door arranged on the outer frame, a floor arranged in the outer frame, a pedestal pan mounted on the floor, and a microbial degradation tank mounted below the floor, wherein a vibrating sieve device is arranged at the lower end of the microbial degradation tank; a collecting tank device is arranged at the lower end of the vibrating sieve device; a microbial degradation tank switch valve is arranged at the bottom of the microbial degradation tank; a stirrer is arranged inside the microbial degradation tank; a feeding pipeline communicated with the microbial degradation tank is also mounted on the floor. A solar battery unit is arranged at the top of the mobile toilet disclosed by the invention and used for supplying power to the overall mobile toilet; EM microbial strains are used for fermentation, so the degradation speed is high, germs can be killed and foul smells can be removed. Moreover, the mobile toilet disclosed by the invention is simple in structure, small in floor space and high in mobility.

The invention relates to a method for rapidly degrading polybrominated diphenyl ether by nano Pd / C catalyst, comprising the steps of: adjusting the pH value of organic series containing decabromodiphenyl oxide to be 10-11, adding the nano Pd / C catalyst, reacting for more than 4h, and controlling the reaction temperature to be 50+ / -5DEG C, wherein the nano Pd / C is solid particles with Pd loaded on activated carbon; the Pd has the mass percent of 5.0+ / -0.05%, and the nano Pd / C has the concentration of 6-20mg / ml in the organic series; the organic series is alcoholic solution of fatty hydrocarbon or aromatic hydrocarbon, wherein the fatty hydrocarbon is normal hexane, and the aromatic hydrocarbon is waste TV shell pyrolysis oil with the main components of methylbenzene or styrene; and as having large specific surface, the nano Pd / C can rapidly aborb and degrade the polybrominated diphenyl ether, and greatly reduces the degradation time compared with nano reducing metal powder. After being used, the nano Pd / C powder can be repeatedly used by being washed by alcohol and water.

The invention belongs to the technical field of a biologically medical material, and concretely relates to a medical absorbable oxycellulose material and a preparation method thereof. The material has dual functions of stopping bleeding and restoring wound. The material takes natural cellulose as a raw material, and is oxidized by an oxidation system under certain technology condition, the obtained product is subjected to acid treatment, washing by water and drying to prepare the medical absorbable oxycellulose material. The oxidation system has the advantages of strong selectivity, mild and controllable condition, and environmental protection of preparation technology. The prepared material has the advantages of rapidly stopping bleeding and rapidly being absorbed, has wound restoration function, can promote the healing of wound, and has wide application value on medical science.

The invention discloses a preparation method and application of a MnO / C positive electrode electrocatalyst. A cheap and easily available carbon material is selected as a base material, the surface ofthe carbon material is loaded with pure-phase MnO by a simple impregnation and high temperature heat treatment process, the prepared MnO / C composite material is used as a positive electrode of a battery, and oxygen gas is catalyzed to oxidize dye wastewater at low voltage. The MnO / C positive electrode electrocatalyst not only greatly improves the mineralization ability of the dye wastewater and shortens the degradation time, but also has good cycle stability.

A controllable biological degradable polyester superfine fiber film consists of PLLA, PLGA or PEG-PLA 95-99.9%, protease K 0.1-5%, PCL or PLCL 90-99% and lipase PS 1-10%. The diameter of fiber is 50nm-600nm and thickness is 10 mu m-100 mu m. It's simple, has short degradable time and adjusting degradable speed.

The invention discloses a bioreactor, which comprises a reactor, a horizontal perforation ventilation pipe, a vertical perforation ventilation pipe, a percolate adjusting tank, a percolate discharge guide pipe, a water seal tank and an air collection cover. The horizontal ventilation pipe is installed at the bottom end inside the reactor, and two ends of the horizontal ventilation pipe are both communicated with the external. One end of the vertical ventilation pipe is communicated with the horizontal ventilation pipe, and the other end of the vertical ventilation pipe is communicated with the external. A submersible sewage pump is arranged in the percolate adjusting tank, a water outlet of the submersible sewage pump is communicated with a water distributor through a percolate recharge pipe, and the water distributor is arranged at the top of the reactor. One end of the percolate discharge guide pipe is communicated with the bottom of the reactor, the other end of the percolate discharge guide pipe is communicated with the percolate adjusting tank, and an outlet of the percolate discharge guide pipe is located above the highest water line of the percolate adjusting tank. The percolate discharge guide pipe, the percolate recharge pipe and the horizontal ventilation pipe are respectively provided with a switch valve. The water seal tank is arranged at the upper end of the reactor, and air collection cover is installed on the water seal tank and covers the opening end at the top of the reactor, and an air discharge port is arranged on the air collection cover. An aerobic-anaerobic-semi-aerobic circulation treatment method of household garbage is further disclosed.

The invention mainly relates to a method for preparing a chitosan oligosaccharide modified biodegradable composite. The method comprises the steps of: firstly, with N,N-dimethyl formamide as a solvent, protecting amino of chitosan oligosaccharide by using phthalic anhydride to prepare a N-methyl o-acyl chitosan oligosaccharide reaction intermediate; secondly, dropwise adding pyridine solution of stannous octoate under protection of nitrogen, initiating an epsilon-caprolactone monomer to carry out ring opening polymerization so that polycaprolactone is grafted on hydroxyl of N-methyl o-acyl chitosan oligosaccharide, so as to generate a chitooligo saccharide-grafted polycaprolactone thermoplastic material; and finally melting and blending LDPE (low-density polyethylene), chitooligo saccharide-grafted caprolactone and polycaprolactone to prepare the biodegradable composite. The blended composite has biological degradability, and is free of poison and wide in application range; deterioration of an ecological environment is effectively improved; and the situations of energy crisis and petroleum resource shortage are solved.

A hydrogel tissue adhesive having decreased gelation time and decreased degradation time is described. The hydrogel tissue adhesive is formed by reacting an oxidized polysaccharide containing aldehyde groups with a water-dispersible, multi-arm amine in the presence of a thiol additive. The thiol additive accelerates the process to form the hydrogel and accelerates the degradation of the hydrogel formed. The hydrogel may be useful as a tissue adhesive or sealant for medical applications, such as a hemostat sealant or to prevent undesired tissue-to-tissue adhesions resulting from trauma or surgery.