Starch-containing microsphere and preparation method and use thereof

Abstract

A starch-containing microsphere has a particle size that exhibits polydispersity with uniform distribution in a particle size concentrated distribution interval. The particle size distribution in the particle size concentrated distribution interval has the following features: equal division of the particle size concentrated distribution interval into n intervals, and a microsphere percentage in each interval is formula (I), 100 n   % ± 1  0 n   % , ( I ) where n is an integer greater than 1. The preparation method of the starch-containing microsphere includes: first reacting starch with a low concentration of epichlorohydrin, and then reacting the resultant product with a surfactant, followed by final crosslinking to give microspheres. The starch-containing microspheres thus prepared are polydisperse starch-containing microspheres with a uniform particle size distribution, with the particle size being in a range of 0.1-500 μm.

1 . A starch-containing microsphere, particle size of the starch-containing microspheres has a uniformly distributed polydispersity in a particle size concentrated distribution interval, characterized by: evenly dividing the particle size concentrated distribution interval into n intervals, wherein the proportion of microspheres in each interval is as follows: 
       
         
           
             
               
                 
                   100 
                   n 
                 
                  
                 
                     
                 
                  
                 % 
               
               ± 
               
                 
                   
                     1 
                      
                     0 
                   
                   n 
                 
                  
                 
                     
                 
                  
                 % 
               
             
           
         
         wherein n is an integer greater than 1, preferably n is an integer between 4 and 10. 
       
     
     
         2 . The starch-containing microsphere of  claim 1 , wherein the controllable particle size range of said starch-containing microsphere is 0.1-500 μm. 
     
     
         3 . (canceled) 
     
     
         4 . The starch-containing microsphere of  claim 1 , wherein the infrared spectrum of said starch-containing microspheres has peaks at 1025 cm −1 -1250 cm −1  assigned to C—N and peaks at 1150 cm −1 -1350 cm −1  assigned to S═O. 
     
     
         5 . The starch-containing microsphere of  claim 1 , wherein said starch-containing microsphere comprises a zwitterionic surfactant with a formula: 
       
         
           
           
               
               
           
         
         wherein m is an integer of 2-6, preferably m is 3 or 4; R is a saturated carbon chain having 1-18 carbon atoms, preferably 12-18 carbon atoms; 
         preferably, except for the terminal carbon atoms, the carbon chain of said zwitterionic surfactants contains hydroxyl, amino or carboxyl groups, and is mono-substituted on the same carbons; 
         preferably, the zwitterionic surfactant is one or more of dimethyldodecylsulfopropyl ammonium salt, dimethylhexadecylsulfoethyl ammonium salt, dimethyloctadecylsulfobutyl ammonium salt, dimethyl (3-hydroxydodecyl) sulfopropyl ammonium salt, dimethyl (6-aminotetradecyl) sulfoethyl ammonium salt. 
       
     
     
         6 - 7 . (canceled) 
     
     
         8 . The starch-containing microsphere of  claim 1 , wherein the content of constitutional units derived from starch in the starch-containing microsphere is between 35 wt % and 95 wt %, preferably between 38 wt % and 85 wt %. 
     
     
         9 . The starch-containing microsphere of  claim 1 , wherein the starch-containing microsphere further comprises a constitutional unit derived from polymerizable monomer, forming a graft copolymer with the constitutional unit derived from starch, wherein the polymerizable monomer is at least one of an anionic monomer, a cationic monomer, a nonionic monomer and a zwitterionic monomer;
 preferably, the zwitterionic monomer is one or more of methacryloyloxyethyl-N,N-dimethyl propane sulfonate, N,N-dimethyl allyl amine propane sulfonate, 4-vinylpyridine propane sulfonate, N-methyl diallyl propane sulfonate and N-methyl diallyl butane sulfonate; the cationic monomer is one or more of methacryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride, dimethyl diallyl ammonium chloride and diethyl diallyl ammonium chloride; the anionic monomer is one or more of acrylic acid, 2-methyl-2-acrylamido propane sulfonic acid, fumaric acid, sodium allyl sulfonate and sodium 2-acryloyloxy isopentene sulfonate; the nonionic monomer is one or more of N-vinyl pyrrolidone, acrylonitrile, vinyl formamide and vinyl acetamide.   
     
     
         10 . A method for preparing starch-containing microspheres, comprising the following steps:
 (1) adding starch into water, then adding a solubilizer, uniformly mixing, and then adding a first cross-linking agent under a cross-linking reaction condition to conduct a reaction;   (2) adding a zwitterionic surfactant into the feed liquid obtained in step (1), and uniformly mixing;   (3) adding a second cross-linking agent and a solution of inorganic salt into the feed liquid obtained in step (2) at 30-60° C. to conduct a reaction, wherein the first cross-linking agent and the second cross-linking agent are the same or different.   
     
     
         11 . The method of  claim 10 , wherein the method further comprises a step (1-1) between step (1) and step (2): adding a polymerizable monomer into the feed liquid obtained in step (1), after fully dissolving and uniformly mixing, adding an initiator to react at 60-80° C. for 3-6 h, and then adding the zwitterionic surfactant to perform step (2). 
     
     
         12 . The method of  claim 10 , wherein the polymerizable monomer in step (1-1) is one or more of a cationic monomer, an anionic monomer, a zwitterionic monomer, and a nonionic monomer;
 preferably, the cationic monomer is one or more of methacryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl trim ethyl ammonium chloride, acryloyloxyethyl dim ethyl benzyl ammonium chloride, dimethyl diallyl ammonium chloride and diethyl diallyl ammonium chloride;   the anionic monomer is one or more of acrylic acid, 2-methyl-2-acrylamido propanesulfonic acid, fumaric acid, sodium allyl sulfonate and sodium 2-acryloyloxy isopentene sulfonate;   the zwitterionic monomer is one or more of methacryloyloxyethyl-N,N-dimethyl propane sulfonate, N,N-dimethyl allyl amine propane sulfonate, 4-vinylpyridine propane sulfonate, N-methyl diallyl propane sulfonate and N-methyl diallyl butane sulfonate;   the nonionic monomer is one or more of N-vinyl pyrrolidone, acrylonitrile, vinyl formamide and vinyl acetamide;   the initiator is any one of potassium persulfate, sodium persulfate and ammonium persulfate.   
     
     
         13 . The method of  claim 10 , wherein the starch in step (1) is one or more of mung bean starch, tapioca starch, ipomoea batatas starch, sweet potato starch, potato starch, wheat starch, water chestnut starch, lotus root starch and corn starch, preferably corn starch and/or potato starch. 
     
     
         14 . The method of  claim 10 , wherein the solubilizer is added in step (1) for mixing at a temperature of 20° C. to 80° C., preferably 30° C. to 60° C., and the weight ratio of the starch to the solubilizer is 1-20:10-50, preferably 5-15:20-40. 
     
     
         15 . The method of  claim 10 , wherein the solubilizer is a compound containing hydroxyl and tertiary nitrogen, preferably one or more of trimethanolamine, triethanolamine, tripropanolamine, and N,N-bisdiethanol amine. 
     
     
         16 . The method of  claim 10 , wherein the reaction time in step (1) is 0.5-4 h, preferably 1-3 h; the reaction temperature is 20-80° C., and preferably 30-60° C. 
     
     
         17 . The method of  claim 10 , wherein the zwitterionic surfactant in step (2) has a structural formula as follows: 
       
         
           
           
               
               
           
         
         wherein m is an integer of 2-6, preferably m is 3 or 4; R is a saturated carbon chain containing 1-18 carbon atoms, preferably 12-18 carbon atoms; 
         preferably, except for terminal carbon atoms, the carbon chain of the zwitterionic surfactant contains substituted hydroxyl, amino or carboxyl, and are mono-substituted on the same carbons; 
         further preferably, the zwitterionic surfactant is one or more of dimethyldodecylsulfopropyl ammonium salt, dimethylhexadecylsulfoethyl ammonium salt, dimethyloctadecylsulfobutyl ammonium salt, dimethyl (3-hydroxydodecyl) sulfopropyl ammonium salt, dimethyl (6-aminotetradecyl) sulfoethyl ammonium salt. 
       
     
     
         18 . The method of  claim 10 , wherein the inorganic salt in step (3) is one or more selected from the group consisting of sodium chloride, sodium bromide, sodium sulfate, sodium sulfite, sodium carbonate, sodium bicarbonate, sodium nitrate, sodium phosphate, sodium hydrogen phosphate, sodium silicate, potassium chloride, potassium bromide, potassium sulfate, potassium sulfite, potassium carbonate, potassium bicarbonate, potassium nitrate, potassium phosphate, potassium hydrogen phosphate, potassium silicate, ammonium chloride, ammonium bromide, ammonium nitrate, calcium chloride, calcium bromide, magnesium chloride, magnesium bromide, magnesium sulfate and magnesium nitrate. 
     
     
         19 . The method of  claim 10 , wherein the first cross-linking agent and the second cross-linking agent are the same, and each independently selected from one or more of epoxy chloropropane, N,N-methylenebisacrylamide, phosphorus oxychloride, sodium trimetaphosphate, adipic acid, and sodium hexametaphosphate. 
     
     
         20 . The method of  claim 10 , wherein the solubilizer is triethanolamine, the first cross-linking agent and the second cross-linking agent are epoxy chloropropane, and the amounts of the water, the starch, the triethanolamine, the epoxy chloropropane, the zwitterionic surfactant and the solution of inorganic salt are, in parts by weight: 100 parts of water, 1-20 parts of starch, 10-50 parts of triethanolamine, 0.105-14.6 parts of epoxy chloropropane, 0.05-10 parts of zwitterionic surfactant and 0.5-200 parts of solution of inorganic salt, wherein the inorganic salt solute accounts for 0.025-50 parts; preferably, 100 parts of water, 5-15 parts of starch, 20-40 parts of triethanolamine, 1.04-7.8 parts of epoxy chloropropane, 1-6 parts of zwitterionic surfactant and 50-150 parts of solution of inorganic salt, wherein the inorganic salt solute accounts for 0.5-30 parts. 
     
     
         21 . The method of  claim 11 , wherein the solubilizer is triethanolamine, the first cross-linking agent and the second cross-linking agent are epoxy chloropropane, and the amounts of the water, the starch, the triethanolamine, the epoxy chloropropane, the zwitterionic surfactant, the monomer, the initiator and the solution of inorganic salt are, in parts by weight: 100 parts of water, 1-20 parts of starch, 10-50 parts of triethanolamine, 0.105-14.6 parts of epoxy chloropropane, 0.05-10 parts of zwitterionic surfactant, 0.1-20 parts of polymerizable monomer, 0.001-0.2 part of initiator and 0.5-200 parts of solution of inorganic salt, wherein the inorganic salt solute accounts for 0.025-50 parts; preferably, 100 parts of water, 5-15 parts of starch, 20-40 parts of triethanolamine, 1.04-7.8 parts of epoxy chloropropane, 1-6 parts of zwitterionic surfactant, 5-15 parts of monomer, 0.02-0.105 part of initiator and 50-150 parts of solution of inorganic salt, wherein the inorganic salt solute accounts for 0.5-30 parts. 
     
     
         22 . The method of  claim 10 , wherein relative to 100 parts by weight of water, the part of the first cross-linking agent in step (1) is 0.005-0.6 parts, preferably 0.04-0.3 parts, and the part of the second cross-linking agent in step (3) is 0.1-14 parts, preferably 1-7.5 parts. 
     
     
         23 - 25 . (canceled) 
     
     
         26 . A method of plugging pores or microcracks in the oil-gas reservoir, comprising using the starch-containing microspheres of  claim 1  as a temporary plugging agent.