CN114805980B - Lignin-reinforced PE water supply pipe mixed ingredient and preparation method thereof - Google Patents
Lignin-reinforced PE water supply pipe mixed ingredient and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a lignin-enhanced PE water supply pipe mixing material which comprises the following components in parts by mass: 100 parts of resin, 2 to 3 parts of modified lignin, 0.5 part of powder silane coupling agent, 0.5 to 1.5 parts of solubilizer, 0.5 to 1.5 parts of carbon black, 0.2 to 1 part of aromatic diol chain extender, 0.5 to 1.5 parts of antioxidant and 0.05 to 0.2 part of lubricant; the modified lignin is obtained by concentrating black liquor and then sequentially adding hydrogen peroxide, lanthanum zinc niobate, a phosphorous acid solution, a cationic polyacrylamide solution and the like for modification treatment; sequentially mixing modified lignin, a powder silane coupling agent, a compatibilizer, an aromatic diol chain extender, carbon black, an antioxidant, a lubricant and resin, and then extruding, drawing, cooling, cutting and screening to obtain the lignin-enhanced PE water supply pipe mixing material. The invention can effectively improve the comprehensive mechanical strength of the composite material, such as tensile strength, impact strength and the like.
Description
Technical Field
The invention belongs to the technical field of novel pipes, and particularly relates to a lignin-enhanced PE water supply pipe mixing material and a preparation method thereof.
Background
Polyethylene water supply pipes (PE water supply pipes) are used as the most representative products in plastic pipelines, and are popularized and applied in a steady rising stage, but the existing PE water supply pipes have the following defects: 1) The whole external pressure resistance is poor, and pits and perforations are easily caused by collision and extrusion of hard stones and metals; 2) No flame retardancy; 3) There is a limit to the maximum service pressure; 4) The product is easy to age under the conditions of sunshine and rain, and the service life is reduced.
Aiming at the problems, the conventional means at present is to perform composite reinforcement on a PE water supply pipe by using organic matters such as carbon fibers, plant fibers, synthetic resin and the like, for example, chinese patent application with the application number of CN202010404752.X discloses a nano-antibacterial PE water supply pipe and a manufacturing process thereof, wherein the nano-antibacterial PE water supply pipe sequentially comprises a wear-resistant layer, an anti-ultraviolet layer, a heat-insulating layer, an antibacterial layer and an anti-sticking wall layer from outside to inside; the nano antibacterial PE water supply pipeline comprises the following components in parts by mass: 100 parts of high molecular resin, 60-70 parts of polyethylene, 8-10 parts of organic compound heat stabilizer, 1-3 parts of coupling agent, 2-5 parts of benzoate plasticizer, 1-3.5 parts of lubricant and 1-5 parts of antioxidant; the wear-resistant layer comprises the following components in parts by weight: 1-5 parts of carbon fiber, 1-5 parts of carbon black, 2-5 parts of nano calcium carbonate and 1-3 parts of wear-resisting agent; the antibacterial layer comprises the following components in parts by weight: 1-5 parts of nano-silver antibacterial master batch, 1-5 parts of surfactant and 1-5 parts of carrier. Also, for example, the chinese patent application with the application number CN202111334714.2 discloses a manufacturing method of a high and low temperature resistant dual-performance hardware sanitary pipe, which comprises 3-8 parts of synthetic resin, 3-8 parts of stabilizer, 5-9 parts of lubricant, 12-17 parts of plasticizer, 2-6 parts of high temperature resistant material and 3-7 parts of low temperature resistant material; the high-temperature resistant material can adopt one or a mixture of a plurality of boride, carbide, nitride, silicide, phosphide and sulfide; the low-temperature resistant material adopts one or a mixture of polyethylene, polytetrafluoroethylene, polytrifluorochloroethylene, parylene and glass fiber tapes bonded by epoxy.
The lignin is a rich renewable resource, is safe and nontoxic, and is a high polymer with a three-dimensional network structure formed by connecting rigid phenylpropane structural units through C-O and C-C bonds. The existing research shows that lignin has a highly cross-linked benzene ring rigid molecular structure, a large number of strong hydrogen bond actions exist among molecules, hard lignin molecules are fully and uniformly dispersed in a PE matrix to form stress concentration points through stirring and shearing in a high-temperature environment of an extruder, and structural damage caused by polymer molecular chain conformation change or displacement change can be prevented when the material is subjected to long-time external force, so that the compressive strength and the deformation resistance of the PE pipe are improved. However, because the polarity difference between lignin and PE is large and the compatibility is poor, the lignin and PE are easy to agglomerate in a resin continuous phase during blending, so that the mechanical property of the prepared composite material is poor, and further industrial application is difficult to realize.
Disclosure of Invention
Aiming at the defects, the invention discloses a lignin-enhanced PE water supply pipe mixed ingredient and a preparation method thereof, which can effectively improve the comprehensive mechanical strength such as tensile strength, impact strength and the like of a composite material.
The invention is realized by adopting the following technical scheme:
a lignin-enhanced PE water supply pipe mixing material comprises the following components in parts by mass: 100 parts of resin, 2-3 parts of modified lignin, 0.5 part of powder silane coupling agent, 0.5-1.5 parts of solubilizer, 0.5-1.5 parts of carbon black, 0.2-1 part of aromatic diol chain extender, 0.5-1.5 parts of antioxidant and 0.05-0.2 part of lubricant;
the preparation method of the modified lignin comprises the following steps:
(1) Concentrating black liquor obtained by alkaline pulping to obtain concentrated solution with the solid content of 20-35 wt%;
(2) Adding hydrogen peroxide and lanthanum zinc niobate into the concentrated solution obtained in the step (1) in sequence, and then stirring and reacting for 90min at the temperature of 80-85 ℃ and the stirring speed of 300r/min to obtain reaction solution A;
(3) Cooling the reaction liquid A obtained in the step (2) to 45-50 ℃, keeping the temperature constant, introducing carbon dioxide gas into the reaction liquid A to enable the pH value of the reaction liquid A to reach 6.0-6.5, then adding a phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min to obtain a reaction liquid B;
(4) Cooling the reaction B obtained in the step (3) to room temperature, adding 2wt% sulfuric acid into the reaction liquid B to enable the pH value of the reaction liquid B to reach 2.0-3.0, and then adding a cationic polyacrylamide solution to obtain flocculent precipitates;
(5) And (4) carrying out filter pressing on the flocculent precipitate obtained in the step (4) to obtain filter residue, and then drying the filter residue until the water content is less than 0.5wt% to obtain the modified lignin.
The black liquor is high-concentration alkaline organic wastewater and contains a large amount of organic matters and inorganic salt substances.
The resin is a polyethylene resin, and may be any one of PE125, PE112, PE100, and PE 80.
Further, the lanthanum zinc niobate is in a lamellar shape, and the chemical formula of the lanthanum zinc niobate is Zn 1/2 LaNb 2 O 7 、Zn 1.5 La 1/3 Nb 2 O 7 And ZnLa 2/3 Nb 2 O 7 Any one of the above; the hydrogen peroxide is 30wt% of hydrogen peroxide; the cationic polyacrylamide solution is 5wt% of cationic polyacrylamide solution; the phosphorous acid solution is 10wt% -25 wt% phosphorous acid aqueous solution.
Further, the volume ratio of the concentrated solution to the hydrogen peroxide is (80-800) to 1; the mass ratio of the volume of the concentrated solution to the lanthanum zinc niobate is (5-25) L:1g; the volume ratio of the concentrated solution to the phosphorous acid solution is (500-3000) to 0.1; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is (1000-2500): 0.1.
Furthermore, the phenolic hydroxyl group content of the modified lignin is more than 2.5 mmol/g, and the number average molecular weight is less than 11000 g/mol.
Furthermore, the powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent is prepared by adopting a silica inert adsorbent as a carrier to adsorb the powdered 3-aminopropyltriethoxysilane.
Further, the silica inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 0.8-1.2 mu m, the porosity is 65-80%, and the specific surface area is 250-400 m 2 /g。
Furthermore, the carbon black has a median particle diameter D50 of less than 25 nm and a specific surface area of 500 m 2 More than g.
Further, the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is one or the combination of resorcinol-bis (beta-hydroxyethyl) ether and hydroquinone-bis (beta-hydroxyethyl) ether in any proportion; the antioxidant is prepared by mixing a hindered phenol antioxidant and a phosphite antioxidant according to a mass ratio of 1.5; the lubricant is polyethylene wax, preferably polyethylene wax with the number average molecular weight of 2000 to 3000.
The technical principle of the invention is as follows:
because lignin is a polyphenol high molecular compound, a large number of active groups are wrapped in the molecule, the intermolecular interaction is strong, the aromatic ring structure is interwoven into a net, and compared with the conventional resin fillers such as calcium carbonate, talc and the like, the lignin has poor reaction activity with the conventional surface modifiers such as stearic acid, silane, aluminate and the like. Thus, the invention is first achieved by reacting H under alkaline conditions with H 2 O 2 The catalyst is lanthanum zinc niobate, which is an oxidant, and the lignin is efficiently catalyzed and depolymerized into a series of molecular chain segments with low molecular weight and multi-aldehyde structure; subsequent neutralization of the solution with carbon dioxideAfter treatment, phosphorous acid is used for catalyzing aldehyde group reduction to form a polyhydroxy micromolecule lignin chain segment, so that the compatibility of lignin and high polymer resin and the reactivity of the lignin with a conventional coupling agent, a compatibilizer and a chain extender are improved; in this case, since the lignin segment has a certain water solubility in a neutral solution, it is necessary to further use H 2 SO 4 Acidifying the solution to fully separate out lignin molecular chain segments, and adding a certain amount of flocculant to make the lignin molecular chain segments easier to precipitate so as to realize solid-liquid separation.
Meanwhile, the invention also selectively adds the components such as solubilizer, chain extender, etc., on one hand, the compatibility between the lignin and the high molecular resin is further improved, on the other hand, the modified lignin obtained by the method of the invention has a large amount of active hydroxyl groups on the molecular chain segment, and the proper chain extender with reactivity is added, so that the bonding force between the lignin and the PE can be further increased, and the residual active hydroxyl groups which can not react with the coupling agent are connected with the PE resin in a chemical bond form through the bridging action of the chain extender, thereby improving the comprehensive performance of the composite material.
The preparation method of the lignin-enhanced PE water supply pipe mixing material comprises the following steps:
s1, adding modified lignin into a high-speed mixer, stirring at the speed of 500 r/min, adding a powdery silane coupling agent to mix for 3 min when the temperature reaches 80-110 ℃, then adding a compatibilizer to continue mixing for 5-10 min, then heating to 140 ℃, adding an aromatic diol chain extender to mix for 5min, then sequentially adding carbon black, an antioxidant, a lubricant and resin, and stirring for 10-12 min to obtain a mixed material;
and S2, adding the mixed material obtained in the step S1 into a screw extruder through a feed inlet for processing, and obtaining the lignin-enhanced PE water supply pipe mixed material after traction, cooling cutting and screening.
Further, in step S2, the diameter of the screw in the screw extruder is 71mm, the ratio of the screw to the groove is 1.5, the depth of the groove is 14mm, the length-diameter ratio of the screw is 40/1, the screw is divided into 10 heating zones, and the temperatures of the 10 heating zones from the feed end are 135 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 160 ℃, 150 ℃ and 140 ℃ in sequence; the screw speed was 500rpm.
Compared with the prior art, the technical scheme has the following beneficial effects:
1. in the conventional catalytic oxidation of lignin, a better product can be obtained by reacting for more than 2 to 5 hours at the temperature of more than 200 ℃. The invention adopts low-temperature alkaline oxidation method and uses H 2 O 2 The catalyst is lanthanum zinc niobate, and the reaction is carried out for 20min at the temperature of 80-85 ℃ to obtain lignin molecular chain segments with low molecular weight and high activity; meanwhile, compared with unmodified lignin macromolecules, the polyhydroxy lignin molecular chain segment obtained by the invention is easier to react with a silane coupling agent, a compatilizer and a chain extender, and shows more excellent thermal fluidity, resin compatibility and reactivity.
2. The invention directly adopts the alkaline pulping black liquor as a raw material source, can reduce the pollution of the black liquor to the environment and realize the resource recycling of the lignin; meanwhile, the invention adopts carbon dioxide as an acidic reagent to neutralize the alkalinity of the reaction system, thereby saving acid and achieving the purpose of carbon neutralization to a certain extent.
3. According to the invention, the powdery coupling agent is used as the lignin hydrophobization modifier, so that the problem of uneven dispersion caused by the fact that the liquid silane coupling agent is bonded on lignin molecules can be effectively solved, and the lignin hydrophobization modification degree is improved. Meanwhile, the interface compatibility between lignin taking phenylpropane as a basic structural unit and PE resin can be improved by adding the reactive compatibilizer PS-co-GMA with a benzene ring structure, and active hydroxyl groups in lignin molecular chain segments can be linked with the PE resin into a whole by adding the reactive aromatic diol chain extender, so that the comprehensive mechanical strength of the composite material, such as tensile strength, impact strength and the like, can be effectively improved.
Drawings
Fig. 1 is an SEM image of the modified lignin obtained in example 1.
FIG. 2 is a GPC chart of the original lignin obtained in comparative example 1 and the modified lignin obtained in example 1, wherein Curve 1 represents the original lignin and Curve 2 represents the modified lignin.
FIG. 3 is a DSC chart of the crude lignin obtained in comparative example 1 and the modified lignin obtained in example 1, wherein curve 1 represents the crude lignin and curve 2 represents the modified lignin.
FIG. 4 is an SEM photograph of brittle sections of compound bars prepared according to the method described in example 1 in the experimental examples.
FIG. 5 is an SEM image of a brittle section of a bar of the compounded material prepared as described in comparative example 1 in the experimental example.
FIG. 6 is a tensile strength-elongation at break test graph of compounded bars prepared in the experimental examples according to the methods described in example 1, comparative example 1 and comparative example 9, in which curve 1 represents the compounded bar in example 1, curve 2 represents the compounded bar in comparative example 1, and curve 3 represents the compounded bar in comparative example 9.
Detailed Description
The invention is further illustrated by the following examples, which are not to be construed as limiting the invention thereto. The specific experimental conditions and methods not indicated in the following examples are generally conventional means well known to those skilled in the art.
Example 1:
a lignin-enhanced PE water supply pipe mixing material comprises the following components in parts by mass: 100 parts of resin, 2 parts of modified lignin, 0.5 part of powder silane coupling agent, 0.85 part of solubilizer, 0.75 part of carbon black, 0.8 part of aromatic diol chain extender, 1.0 part of antioxidant and 0.15 part of lubricant; the black liquor is high-concentration alkaline organic wastewater and contains a large amount of organic matters and inorganic salt substances; the resin is PE125; the powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent is prepared by adopting a siliceous inert adsorbent as a carrier to adsorb the powdered 3-aminopropyltriethoxysilane; the silica inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 1.02 mu m, the porosity is 72.3 percent, and the specific surface area is 287.1 m 2 (ii)/g; the carbon black had a median particle diameter D50 of 20 nm, as shown in the tableThe area is 1200m 2 (ii)/g; the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is obtained by mixing resorcinol-bis (beta-hydroxyethyl) ether and hydroquinone-bis (beta-hydroxyethyl) ether according to the mass ratio of 7:3; the antioxidant is prepared by mixing a hindered phenol antioxidant and a phosphite antioxidant according to a mass ratio of 1.5; the lubricant is polyethylene wax with the number average molecular weight of 3000;
the preparation method of the modified lignin comprises the following steps:
(1) Concentrating black liquor obtained by alkaline pulping to obtain concentrated solution with solid content of 30 wt%;
(2) Adding hydrogen peroxide and lanthanum zinc niobate into the concentrated solution obtained in the step (1) in sequence, and then stirring and reacting for 90min at 82 ℃ and at a stirring speed of 300r/min to obtain a reaction solution A; the lanthanum zinc niobate is in a lamellar shape, and the chemical formula of the lanthanum zinc niobate is Zn 1/2 LaNb 2 O 7 (ii) a The hydrogen peroxide is 30wt% of hydrogen peroxide; the volume ratio of the concentrated solution to the hydrogen peroxide is 1000; the mass ratio of the volume of the concentrated solution to the lanthanum zinc niobate is 1000L;
(3) Cooling the reaction liquid A obtained in the step (2) to 45 ℃, keeping the temperature constant, introducing carbon dioxide gas into the reaction liquid A to enable the pH value of the reaction liquid A to reach 6.2, then adding a phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min to obtain a reaction liquid B; the volume ratio of the concentrated solution to the phosphorous acid solution is 1000; the phosphorous acid solution is a 20wt% phosphorous acid aqueous solution;
(4) Cooling the reaction B obtained in the step (3) to room temperature, adding 2wt% sulfuric acid into the reaction liquid B to enable the pH value of the reaction liquid B to reach 2.5, and then adding a cationic polyacrylamide solution to obtain flocculent precipitates; the cationic polyacrylamide solution is 5wt% of cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 1000;
(5) And (4) carrying out filter pressing on the flocculent precipitate obtained in the step (4) to obtain filter residue, and then drying the filter residue until the water content is less than 0.5wt% to obtain the modified lignin.
The preparation method of the lignin-enhanced PE water supply pipe mixing material comprises the following steps:
s1, adding modified lignin into a high-speed mixer, stirring at the speed of 500 r/min, adding a powdery silane coupling agent to mix for 3 min when the temperature reaches 105 ℃, then adding a compatibilizer to continue mixing for 5min, then heating to 140 ℃, then adding an aromatic diol chain extender to mix for 5min, then sequentially adding carbon black, an antioxidant, a lubricant and resin, and stirring for 11min to obtain a mixed material;
s2, adding the mixed material obtained in the step S1 into a screw extruder through a feed port for processing, and obtaining a lignin-enhanced PE water supply pipe mixed material through traction, cooling cutting and screening; the diameter of a screw in the screw extruder is 71mm, the ratio of screw grooves is 1.5, the depth of the screw grooves is 14mm, the length-diameter ratio of the screw is 40/1, the screw is divided into 10 heating zones, and the temperatures of the 10 heating zones from the feed end are 135 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 160 ℃, 150 ℃ and 140 ℃ in sequence; the screw speed was 500rpm.
Example 2:
a lignin-enhanced PE water supply pipe mixing material comprises the following components in parts by mass: 100 parts of resin, 3 parts of modified lignin, 0.5 part of powder silane coupling agent, 0.5 part of solubilizer, 0.85 part of carbon black, 0.3 part of aromatic diol chain extender, 1.0 part of antioxidant and 0.1 part of lubricant; the black liquor is high-concentration alkaline organic wastewater and contains a large amount of organic matters and inorganic salt substances; the resin is PE100; the powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent is prepared by adopting a silica inert adsorbent as a carrier to adsorb the powdered 3-aminopropyltriethoxysilane; the silica inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 1.2 mu m, the porosity is 68.8 percent, and the specific surface area is 205.0 m 2 (ii)/g; the carbon black has a median particle diameter D50 of 25 nm and a specific surface area of 925.3 m 2 (ii)/g; the compatibilizer is styrene-methyl propyleneGlycidyl acrylate copolymers; the aromatic diol chain extender is obtained by mixing resorcinol-bis (beta-hydroxyethyl) ether and hydroquinone-bis (beta-hydroxyethyl) ether according to the mass ratio of 1:1; the antioxidant is prepared by mixing a hindered phenol antioxidant and a phosphite antioxidant according to a mass ratio of 1.5; the lubricant is polyethylene wax with the number average molecular weight of 3000;
the preparation method of the modified lignin comprises the following steps:
(1) Concentrating black liquor obtained by alkaline pulping to obtain concentrated solution with solid content of 35 wt%;
(2) Adding hydrogen peroxide and lanthanum zinc niobate into the concentrated solution obtained in the step (1) in sequence, and then stirring and reacting for 90min at the temperature of 80 ℃ and at the stirring speed of 300r/min to obtain a reaction solution A; the lanthanum zinc niobate is in a lamellar shape, and the chemical formula of the lanthanum zinc niobate is ZnLa 2/3 Nb 2 O 7 (ii) a The hydrogen peroxide is 30wt% of hydrogen peroxide; the volume ratio of the concentrated solution to hydrogen peroxide is 1200; the mass ratio of the volume of the concentrated solution to the lanthanum zinc niobate is 1200L 50g;
(3) Cooling the reaction liquid A obtained in the step (2) to 45-50 ℃, keeping the temperature constant, introducing carbon dioxide gas into the reaction liquid A to enable the pH value of the reaction liquid A to reach 6.0-6.5, then adding a phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min to obtain a reaction liquid B; the volume ratio of the concentrated solution to the phosphorous acid solution is 1200.12; the phosphorous acid solution is a 25wt% phosphorous acid aqueous solution;
(4) Cooling the reaction B obtained in the step (3) to room temperature, adding 2wt% sulfuric acid into the reaction liquid B to enable the pH value of the reaction liquid B to reach 3.0, and then adding a cationic polyacrylamide solution to obtain flocculent precipitates; the cationic polyacrylamide solution is 5wt% of cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 1200.08;
(5) And (4) carrying out filter pressing on the flocculent precipitate obtained in the step (4) to obtain filter residue, and then drying the filter residue until the water content is less than 0.5wt% to obtain the modified lignin.
The preparation method of the lignin-enhanced PE water supply pipe mixing material comprises the following steps:
s1, adding modified lignin into a high-speed mixer, stirring at the speed of 500 r/min, adding a powdery silane coupling agent to mix for 3 min when the temperature reaches 110 ℃, then adding a compatibilizer to continue mixing for 7min, then heating to 140 ℃, then adding an aromatic diol chain extender to mix for 5min, then sequentially adding carbon black, an antioxidant, a lubricant and resin, and stirring for 10.5min to obtain a mixed material;
s2, adding the mixed material obtained in the step S1 into a screw extruder through a feed inlet for processing, and obtaining a lignin-enhanced PE water supply pipe mixed material after traction, cooling cutting and screening; the diameter of a screw in the screw extruder is 71mm, the ratio of screw grooves is 1.5, the depth of the screw groove is 14mm, the length-diameter ratio of the screw is 40/1, the screw is divided into 10 heating zones, and the temperatures of the 10 heating zones from the feed end are 135 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 160 ℃, 150 ℃ and 140 ℃ in sequence; the screw speed was 500rpm.
Example 3:
a lignin-enhanced PE water supply pipe mixing material comprises the following components in parts by mass: 100 parts of resin, 2 parts of modified lignin, 0.5 part of powder silane coupling agent, 0.9 part of solubilizer, 1.25 parts of carbon black, 0.2 part of aromatic diol chain extender, 1.25 parts of antioxidant and 0.2 part of lubricant; the black liquor is high-concentration alkaline organic wastewater and contains a large amount of organic matters and inorganic salt substances; the resin is PE112; the powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent is prepared by adopting a silica inert adsorbent as a carrier to adsorb the powdered 3-aminopropyltriethoxysilane; the silica inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 0.8 mu m, the porosity is 80 percent, and the specific surface area is 289.36m 2 (ii)/g; the carbon black has a median particle diameter D50 of 10 nm and a specific surface area of 800m 2 (ii)/g; the compatibilizer is a styrene-glycidyl methacrylate copolymer; chain extension of the aromatic diolThe agent is obtained by mixing resorcinol-bis (beta-hydroxyethyl) ether and hydroquinone-bis (beta-hydroxyethyl) ether according to the mass ratio of 1:4; the antioxidant is prepared by mixing a hindered phenol antioxidant and a phosphite antioxidant according to a mass ratio of 1.5; the lubricant is polyethylene wax with the number average molecular weight of 3000;
the preparation method of the modified lignin comprises the following steps:
(1) Concentrating black liquor obtained by alkaline pulping to obtain concentrated solution with solid content of 35 wt%;
(2) Adding hydrogen peroxide and lanthanum zinc niobate into the concentrated solution obtained in the step (1) in sequence, and then stirring and reacting for 90min at 80 ℃ and at the stirring speed of 300r/min to obtain a reaction solution A; the lanthanum zinc niobate is in a lamellar shape, and the chemical formula of the lanthanum zinc niobate is Zn 1.5 La 1/3 Nb 2 O 7 (ii) a The hydrogen peroxide is 30 wt%; the volume ratio of the concentrated solution to the hydrogen peroxide is 80; the mass ratio of the volume of the concentrated solution to the lanthanum zinc niobate is 800L;
(3) Cooling the reaction liquid A obtained in the step (2) to 50 ℃, keeping the temperature constant, introducing carbon dioxide gas into the reaction liquid A to enable the pH value of the reaction liquid A to reach 6.0, then adding a phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min to obtain a reaction liquid B; the volume ratio of the concentrated solution to the phosphorous acid solution is 800.03; the phosphorous acid solution is a 10wt% phosphorous acid aqueous solution;
(4) Cooling the reaction B obtained in the step (3) to room temperature, adding 2wt% sulfuric acid into the reaction liquid B to enable the pH value of the reaction liquid B to reach 2.0, and then adding a cationic polyacrylamide solution to obtain flocculent precipitates; the cationic polyacrylamide solution is 5wt% of cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 800.08;
(5) And (4) carrying out filter pressing on the flocculent precipitate obtained in the step (4) to obtain filter residue, and then drying the filter residue until the water content is less than 0.5wt% to obtain the modified lignin.
The preparation method of the lignin-enhanced PE water supply pipe mixing material comprises the following steps:
s1, adding modified lignin into a high-speed mixer, stirring at the speed of 500 r/min, adding a powdery silane coupling agent to mix for 3 min when the temperature reaches 95 ℃, then adding a compatibilizer to continue mixing for 10min, then heating to 140 ℃, then adding an aromatic diol chain extender to mix for 5min, then sequentially adding carbon black, an antioxidant, a lubricant and resin, and stirring for 10min to obtain a mixed material;
s2, adding the mixed material obtained in the step S1 into a screw extruder through a feed inlet for processing, and obtaining a lignin-enhanced PE water supply pipe mixed material after traction, cooling cutting and screening; the diameter of a screw in the screw extruder is 71mm, the ratio of screw grooves is 1.5, the depth of the screw groove is 14mm, the length-diameter ratio of the screw is 40/1, the screw is divided into 10 heating zones, and the temperatures of the 10 heating zones from the feed end are 135 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 160 ℃, 150 ℃ and 140 ℃ in sequence; the screw speed was 500rpm.
Example 4:
a lignin-enhanced PE water supply pipe mixing material comprises the following components in parts by mass: 100 parts of resin, 2.5 parts of modified lignin, 0.5 part of powder silane coupling agent, 1 part of solubilizer, 0.5 part of carbon black, 0.35 part of aromatic diol chain extender, 1.0 part of antioxidant and 0.18 part of lubricant; the black liquor is high-concentration alkaline organic wastewater and contains a large amount of organic matters and inorganic salt substances; the resin is PE80; the powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent is prepared by adopting a silica inert adsorbent as a carrier to adsorb the powdered 3-aminopropyltriethoxysilane; the silica inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 1.0 mu m, the porosity is 65 percent, and the specific surface area is 351.15m 2 (ii)/g; the carbon black has a median particle diameter D50 of 18nm and a specific surface area of 750 m 2 (iv) g; the compatibilizer is a styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is resorcinol-bis (beta-hydroxyethyl) ether and hydroquinone-bis (beta-hydroxyethyl) etherObtained by mixing according to the mass ratio of 1:2; the antioxidant is prepared by mixing a hindered phenol antioxidant and a phosphite antioxidant according to a mass ratio of 1.5; the lubricant is polyethylene wax with the number average molecular weight of 2000;
the preparation method of the modified lignin comprises the following steps:
(1) Concentrating black liquor obtained by alkaline pulping to obtain concentrated liquor with the solid content of 28 wt%;
(2) Adding hydrogen peroxide and lanthanum zinc niobate into the concentrated solution obtained in the step (1) in sequence, and then stirring and reacting for 90min at 84 ℃ and at the stirring speed of 300r/min to obtain a reaction solution A; the lanthanum zinc niobate is in a lamellar shape, and the chemical formula of the lanthanum zinc niobate is Zn 1/2 LaNb 2 O 7 (ii) a The hydrogen peroxide is 30wt% of hydrogen peroxide; the volume ratio of the concentrated solution to hydrogen peroxide is 1800; the mass ratio of the volume of the concentrated solution to the lanthanum zinc niobate is 1800L to 200g;
(3) Cooling the reaction liquid A obtained in the step (2) to 458 ℃ and keeping the temperature constant, then introducing carbon dioxide gas into the reaction liquid A to ensure that the pH value of the reaction liquid A reaches 6.5, then adding a phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min to obtain a reaction liquid B; the volume ratio of the concentrated solution to the phosphorous acid solution is 1800; the phosphorous acid solution is a 12wt% phosphorous acid aqueous solution;
(4) Cooling the reaction B obtained in the step (3) to room temperature, adding 2wt% sulfuric acid into the reaction liquid B to enable the pH value of the reaction liquid B to reach 2.5, and then adding a cationic polyacrylamide solution to obtain flocculent precipitates; the cationic polyacrylamide solution is 5wt% of cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 1800;
(5) And (4) carrying out filter pressing on the flocculent precipitate obtained in the step (4) to obtain filter residue, and then drying the filter residue until the water content is less than 0.5wt% to obtain the modified lignin.
The preparation method of the lignin-enhanced PE water supply pipe blending material comprises the following steps:
s1, adding modified lignin into a high-speed mixer, stirring at the speed of 500 r/min, adding a powdery silane coupling agent to mix for 3 min when the temperature reaches 102 ℃, then adding a compatibilizer to continue mixing for 8min, then heating to 140 ℃, then adding an aromatic diol chain extender to mix for 5min, then sequentially adding carbon black, an antioxidant, a lubricant and resin, and stirring for 12min to obtain a mixed material;
s2, adding the mixed material obtained in the step S1 into a screw extruder through a feed inlet for processing, and obtaining a lignin-enhanced PE water supply pipe mixed material after traction, cooling cutting and screening; the diameter of a screw in the screw extruder is 71mm, the ratio of screw grooves is 1.5, the depth of the screw groove is 14mm, the length-diameter ratio of the screw is 40/1, the screw is divided into 10 heating zones, and the temperatures of the 10 heating zones from the feed end are 135 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 160 ℃, 150 ℃ and 140 ℃ in sequence; the screw speed was 500rpm.
Example 5:
a lignin-enhanced PE water supply pipe mixing material comprises the following components in parts by mass: 100 parts of resin, 2 parts of modified lignin, 0.5 part of powder silane coupling agent, 0.5 part of solubilizer, 0.5 part of carbon black, 0.2 part of aromatic diol chain extender, 0.5 part of antioxidant and 0.05 part of lubricant; the black liquor is high-concentration alkaline organic wastewater and contains a large amount of organic matters and inorganic salt substances; the resin is PE100; the powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent is prepared by adopting a siliceous inert adsorbent as a carrier to adsorb the powdered 3-aminopropyltriethoxysilane; the silica inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 0.8 mu m, the porosity is 65 percent, and the specific surface area is 250 m 2 (ii)/g; the carbon black has a median particle diameter D50 of 25 nm and a specific surface area of 500 m 2 (ii)/g; the compatibilizer is a styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is resorcinol-bis (beta-hydroxyethyl) ether; the antioxidant is prepared by mixing a hindered phenol antioxidant and a phosphite antioxidant according to a mass ratio of 1.5(ii) a The lubricant is polyethylene wax with the number average molecular weight of 2500;
the preparation method of the modified lignin comprises the following steps:
(1) Concentrating black liquor obtained by alkaline pulping to obtain concentrated liquor with the solid content of 20 wt%;
(2) Adding hydrogen peroxide and lanthanum zinc niobate into the concentrated solution obtained in the step (1) in sequence, and then stirring and reacting for 90min at 80 ℃ and at the stirring speed of 300r/min to obtain a reaction solution A; the lanthanum zinc niobate is in a lamellar shape, and the chemical formula of the lanthanum zinc niobate is Zn 1/2 LaNb 2 O 7 (ii) a The hydrogen peroxide is 30wt% of hydrogen peroxide; the volume ratio of the concentrated solution to the hydrogen peroxide is 80; the mass ratio of the volume of the concentrated solution to the lanthanum zinc niobate is 5L;
(3) Cooling the reaction liquid A obtained in the step (2) to 45 ℃, keeping the temperature constant, introducing carbon dioxide gas into the reaction liquid A to enable the pH value of the reaction liquid A to reach 6.0, then adding a phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min to obtain a reaction liquid B; the volume ratio of the concentrated solution to the phosphorous acid solution is 500.1; the phosphorous acid solution is a 10wt% phosphorous acid aqueous solution;
(4) Cooling the reaction B obtained in the step (3) to room temperature, adding 2wt% sulfuric acid into the reaction liquid B to enable the pH value of the reaction liquid B to reach 2.0, and then adding a cationic polyacrylamide solution to obtain flocculent precipitates; the cationic polyacrylamide solution is 5wt% of cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 1000;
(5) And (4) carrying out filter pressing on the flocculent precipitate obtained in the step (4) to obtain filter residue, and then drying the filter residue until the water content is less than 0.5wt% to obtain the modified lignin.
The preparation method of the lignin-enhanced PE water supply pipe mixing material comprises the following steps:
s1, adding modified lignin into a high-speed mixer, stirring at the speed of 500 r/min, adding a powdery silane coupling agent to mix for 3 min when the temperature reaches 80 ℃, then adding a compatibilizer to continue mixing for 5min, then heating to 140 ℃, then adding an aromatic diol chain extender to mix for 5min, then sequentially adding carbon black, an antioxidant, a lubricant and resin, and stirring for 10min to obtain a mixed material;
s2, adding the mixed material obtained in the step S1 into a screw extruder through a feed inlet for processing, and obtaining a lignin-enhanced PE water supply pipe mixed material after traction, cooling cutting and screening; the diameter of a screw in the screw extruder is 71mm, the ratio of screw grooves is 1.5, the depth of the screw groove is 14mm, the length-diameter ratio of the screw is 40/1, the screw is divided into 10 heating zones, and the temperatures of the 10 heating zones from the feed end are 135 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 160 ℃, 150 ℃ and 140 ℃ in sequence; the screw speed was 500rpm.
Example 6:
a lignin-enhanced PE water supply pipe mixing material comprises the following components in parts by mass: 100 parts of resin, 3 parts of modified lignin, 0.5 part of powder silane coupling agent, 1.5 parts of solubilizer, 1.5 parts of carbon black, 1 part of aromatic diol chain extender, 1.5 parts of antioxidant and 0.2 part of lubricant; the black liquor is high-concentration alkaline organic wastewater and contains a large amount of organic matters and inorganic salt substances; the resin is PE80; the powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent is prepared by adopting a silica inert adsorbent as a carrier to adsorb the powdered 3-aminopropyltriethoxysilane; the silica inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 1.2 mu m, the porosity is 80 percent, and the specific surface area is 400 m 2 (ii)/g; the carbon black has a median particle diameter D50 of 10 nm and a specific surface area of 500 m 2 (ii)/g; the compatibilizer is a styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is hydroquinone-bis (beta-hydroxyethyl) ether; the antioxidant is prepared by mixing a hindered phenol antioxidant and a phosphite antioxidant according to a mass ratio of 1.5; the lubricant is polyethylene wax with the number average molecular weight of 2500;
the preparation method of the modified lignin comprises the following steps:
(1) Concentrating black liquor obtained by alkaline pulping to obtain concentrated solution with solid content of 35 wt%;
(2) Adding hydrogen peroxide and lanthanum zinc niobate into the concentrated solution obtained in the step (1) in sequence, and then stirring and reacting for 90min at 85 ℃ and at the stirring speed of 300r/min to obtain a reaction solution A; the lanthanum zinc niobate is in a lamellar shape, and the chemical formula of the lanthanum zinc niobate is ZnLa 2/3 Nb 2 O 7 (ii) a The hydrogen peroxide is 30 wt%; the volume ratio of the concentrated solution to hydrogen peroxide is 800; the mass ratio of the volume of the concentrated solution to the lanthanum zinc niobate is 25L;
(3) Cooling the reaction liquid A obtained in the step (2) to 45-50 ℃, keeping the temperature constant, introducing carbon dioxide gas into the reaction liquid A to enable the pH value of the reaction liquid A to reach 6.0-6.5, then adding a phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min to obtain a reaction liquid B; the volume ratio of the concentrated solution to the phosphorous acid solution is 3000; the phosphorous acid solution is a 25wt% phosphorous acid aqueous solution;
(4) Cooling the reaction B obtained in the step (3) to room temperature, adding 2wt% sulfuric acid into the reaction liquid B to enable the pH value of the reaction liquid B to reach 3.0, and then adding a cationic polyacrylamide solution to obtain flocculent precipitates; the cationic polyacrylamide solution is 5wt% of cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 2500;
(5) And (5) carrying out filter pressing on the flocculent precipitate obtained in the step (4) to obtain filter residue, and then drying the filter residue until the water content is less than 0.5wt% to obtain the modified lignin.
The preparation method of the lignin-enhanced PE water supply pipe blending material comprises the following steps:
s1, adding modified lignin into a high-speed mixer, stirring at the speed of 500 r/min, adding a powdery silane coupling agent to mix for 3 min when the temperature reaches 110 ℃, then adding a compatibilizer to continue mixing for 10min, then heating to 140 ℃, then adding an aromatic diol chain extender to mix for 5min, then sequentially adding carbon black, an antioxidant, a lubricant and resin, and stirring for 12min to obtain a mixed material;
s2, adding the mixed material obtained in the step S1 into a screw extruder through a feed inlet for processing, and obtaining a lignin-enhanced PE water supply pipe mixed material after traction, cooling cutting and screening; the diameter of a screw in the screw extruder is 71mm, the ratio of screw grooves is 1.5, the depth of the screw grooves is 14mm, the length-diameter ratio of the screw is 40/1, the screw is divided into 10 heating zones, and the temperatures of the 10 heating zones from the feed end are 135 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 160 ℃, 150 ℃ and 140 ℃ in sequence; the screw speed was 500rpm.
Comparative example 1:
the difference between this comparative example and the lignin-enhanced PE feed pipe furnish of example 1 is that the modified lignin was replaced with raw lignin, which was prepared by concentrating alkaline pulping black liquor to a concentrated liquor having a solids content of 30wt%, and then taking 1000L of the concentrated liquor and adding 72 wt% H under agitation 2 SO 4 Making the solution reach 2~3 to form a large amount of flocculent precipitates, fully standing, performing plate-frame filter pressing to realize solid-liquid separation, washing the obtained solid with a large amount of deionized water until the washing liquid is neutral, and performing vacuum drying at 60 ℃ until the water content is less than 0.5wt% to obtain the original lignin; the preparation method of the lignin-enhanced PE water supply pipe blending material is consistent with the method in example 1.
Comparative example 2:
the comparative example differs from the lignin-enhanced PE pipe furnish of example 1 only in that the powdered silane coupling agent is not used and the other steps are the same as the process described in example 1.
Comparative example 3:
the only difference between this comparative example and the lignin-enhanced PE water pipe admixture described in example 1 is that the powdered silane coupling agent is only powdered 3-aminopropyltriethoxysilane, calcium silicate is not used for adsorption, and the other steps are the same as those described in example 1.
Comparative example 4:
the comparative example differs from the lignin-enhanced PE feeder mix described in example 1 only in that the solubilizing agent was not used and the other steps were consistent with the method described in example 1.
Comparative example 5:
the comparative example differs from the lignin-enhanced PE pipe furnish of example 1 only in that the solubilizing agent is PE-g-MAH and the other steps are consistent with the method described in example 1.
Comparative example 6:
this comparative example differs from the lignin-enhanced PE water pipe furnish blend described in example 1 only in that the chain extender is not used and the other steps are consistent with the method described in example 1.
Comparative example 7:
this comparative example differs from the lignin-enhanced PE water pipe furnish of example 1 only in that the chain extender is Joncryl ADR 4370F and the other steps are in accordance with the method described in example 1.
Comparative example 8:
the comparative example differs from the lignin-enhanced PE feed pipe furnish of example 1 only in that no lanthanum zinc niobate is added during the preparation of the modified lignin and the other steps are consistent with the method described in example 1.
Comparative example 9:
the comparative example differs from the lignin-enhanced PE water pipe furnish of example 1 only in that no modified lignin was added and the other steps were identical to the method described in example 1.
Experimental example:
modified lignin and furnish were prepared as described in example 1~6 and comparative example 1~9 and tested as follows, see tables 1 and 2.
(1) And (3) lignin structure determination:
(2) And (3) performance determination of the mixed materials: the obtained mixture was molded by an injection molding machine at 170 ℃ under 45MPa to prepare a dumbbell-type standard tensile test specimen. The tensile strength and the elongation at break are tested by an electronic universal testing machine, and the impact strength is tested by a cantilever beam impact tester. And (3) testing conditions are as follows: testing the tensile strength and the elongation at break according to the reference standard GB/T1040.2-2006; the impact strength is tested according to the standard GB/T1043.1-2008; the obtained mixed materials are made into PE water supply pipes with specifications of DN110 and SDR17 through a pipeline extruder, and the hydrostatic strength, the oxidation induction time and the longitudinal retraction rate of the product are measured according to the national standard GB/T13663-2018.
TABLE 1 Lignin assay results obtained by different methods
TABLE 2 Performance test results of large-caliber polyethylene water supply pipe prepared by different methods
As can be seen from Table 1, in comparative example 1, 1000L of the papermaking black liquor with the solid content of 30wt% is recovered to obtain 188.60 Kg, and the yield of the phenolic hydroxyl group content is 2.45 mmol/g; in examples 1 to 6, 1000L of the black liquor having a solid content of 30wt% was recovered to obtain lignin of 190 Kg or more and a phenolic hydroxyl group content of 2.5 mmol/g or more. The invention can effectively increase the number of active hydroxyl in lignin molecular chain segment after low-temperature oxidation-phosphorous acid reduction-acid precipitation flocculation treatment, and further is easier to react with silane coupling agent, compatilizer and chain extender. Meanwhile, the lignin in the papermaking black liquor is composed of acid-soluble lignin and acid-insoluble lignin, and compared with the comparative example 1, the method has the advantage that the higher lignin yield is obtained, which shows that after the low-temperature oxidation-phosphorous acid reduction-acid precipitation flocculation treatment, part of acid-soluble lignin can be promoted to be converted into acid-insoluble lignin, and then precipitation is formed.
From table 2, it can be seen that, in the material ratio of example 1, no matter the compatibilizer or chain extender or lanthanum zinc niobate catalyst is removed, or the conventional PE-g-MAH compatibilizer is used to replace the styrene-glycidyl methacrylate copolymer (PS-co-GMA) compatibilizer required by the present invention, or the conventional Joncryl ADR 4370F chain extender is used to replace the resorcinol-bis (β -hydroxyethyl) ether/hydroquinone-bis (β -hydroxyethyl) ether hybrid chain extender required by the present invention, the mechanical property indexes of the obtained lignin-PE composite material, such as tensile strength, elongation at break, and impact strength, are all reduced to different degrees, which shows that the modified lignin obtained by the present invention can perform a synergistic effect with the compatibilizer and chain extender required by the present invention, thereby obtaining a better comprehensive property.
Meanwhile, as can be seen from fig. 1, after the low-temperature oxidation-phosphorous acid reduction-acidification flocculation treatment of the invention, the raw lignin particles are disintegrated into many fine particles with different sizes, and the particle size is about 1.0 to 2 μm.
As can be seen from fig. 2, the GPC spectrum of the original lignin (comparative example 1) is not a single peak, but shows double peaks of continuous distribution, i.e., number average molecular weight 107106 g/mol, molecular weight distribution (PDI = 2.159) and number average molecular weight 11270g/mol, and molecular weight distribution (PDI = 1.371), indicating that the molecular weight distribution of the original lignin (comparative example 1) is broad and there is a large difference between molecules. After the low-temperature oxidation-phosphorous acid reduction-acid precipitation flocculation treatment, the GPC spectrogram of the obtained modified lignin presents a single distribution peak, and the number average molecular weight and the molecular weight distribution are 4897 g/mol and 1.360 respectively, which shows that the technical treatment of the invention can effectively reduce the molecular weight of the lignin and form more small molecular lignin chain segments.
Since lignin is an amorphous thermoplastic polymer, has no melting point, but has a glass transition property, and is softened and has fluidity and tackiness under a certain pressure, the glass transition temperature (Tg) of lignin is a key factor affecting the processability of lignin-PE. As can be seen from FIG. 3, the glass transition temperature of the original lignin (comparative example 1) is 138.1 ℃, and the glass transition temperature of the obtained modified lignin is reduced to 128.3 ℃ after the low-temperature oxidation-phosphorous acid reduction-acid precipitation flocculation treatment of the invention, which shows that the glass transition temperature of the lignin can be effectively reduced by the technical treatment of the invention, the fluidity of the composite material under the lower temperature condition can be increased, and the processing and forming of the composite material are facilitated.
As can be seen from fig. 4 and 5, in comparative example 1 (fig. 5), the lignin is in a hard granular form and has an agglomeration phenomenon, and there is an interfacial difference between the lignin and the PE matrix resin, and the gap between the lignin and the PE matrix resin is obvious, which indicates that the compatibility between the original lignin and the PE resin is poor, and it is difficult to obtain a composite material with a continuous and uniform interface by simply melt extrusion. In the lignin-PE composite material obtained in example 1 (fig. 4), lignin and PE matrix resin are almost integrated, and no obvious gap or hole is observed between them, which indicates that the compatibility between lignin and PE resin can be effectively improved by the treatment of the present invention.
As can be seen in FIG. 6, the tensile strength and elongation at break of PE were 24.35 MPa and 1736.27%, respectively; the tensile strength and elongation at break of the composite material prepared by directly blending the original lignin (comparative example 1) are 14.39MPa and 588.38 respectively, which shows that the composite material prepared by directly blending the original lignin and PE has phase defects and is easy to become a breaking point when stressed, thereby reducing the mechanical property of the composite material. The tensile strength and the elongation at break of the lignin-PE composite material obtained in the embodiment 1 are respectively 32.49 MPa and 1834.36 which are greatly improved compared with PE, which shows that the composite material obtained by the technology of the invention can effectively improve the comprehensive properties of PE, such as the tensile strength, the elongation at break and the like.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (6)
1. The lignin-enhanced PE water supply pipe mixing material is characterized in that: the paint comprises the following components in parts by mass: 100 parts of resin, 2-3 parts of modified lignin, 0.5 part of powder silane coupling agent, 0.5-1.5 parts of compatibilizer, 0.5-1.5 parts of carbon black, 0.2-1 part of aromatic diol chain extender, 0.5-1.5 parts of antioxidant and 0.05-0.2 part of lubricant;
the preparation method of the modified lignin comprises the following steps:
(1) Concentrating black liquor obtained by alkaline pulping to obtain concentrated solution with the solid content of 20-35 wt%;
(2) Adding hydrogen peroxide and lanthanum zinc niobate into the concentrated solution obtained in the step (1) in sequence, and then stirring and reacting for 90min at the temperature of 80-85 ℃ and the stirring speed of 300r/min to obtain a reaction solution A;
(3) Cooling the reaction liquid A obtained in the step (2) to 45-50 ℃, keeping the temperature constant, introducing carbon dioxide gas into the reaction liquid A to enable the pH value of the reaction liquid A to reach 6.0-6.5, then adding a phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min to obtain a reaction liquid B;
(4) Cooling the reaction liquid B obtained in the step (3) to room temperature, adding 2wt% sulfuric acid into the reaction liquid B to enable the pH value of the reaction liquid B to reach 2.0-3.0, and then adding a cationic polyacrylamide solution to obtain flocculent precipitates;
(5) Carrying out filter pressing on the flocculent precipitate obtained in the step (4) to obtain filter residue, and then drying the filter residue until the water content is less than 0.5wt% to obtain modified lignin;
the lanthanum zinc niobate is in a lamellar shape, and the chemical formula of the lanthanum zinc niobate is Zn 1/2 LaNb 2 O 7 、Zn 1.5 La 1/3 Nb 2 O 7 And ZnLa 2/3 Nb 2 O 7 Any one of the above; the hydrogen peroxide is 30 wt%; the cationic polyacrylamide solution is 5wt% of cationic polyacrylamide solution; the phosphorous acid solution is 10-25 wt% phosphorous acid aqueous solution; the volume ratio of the concentrated solution to the hydrogen peroxide is (80-800) to 1; the mass ratio of the volume of the concentrated solution to the lanthanum zinc niobate is (5-25) L:1g; the volume ratio of the concentrated solution to the phosphorous acid solution is (500-3000) to 0.1; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is (1000-2500) to 0.1; the phenolic hydroxyl content of the modified lignin is more than 2.5 mmol/g, and the number average molecular weight is less than 11000 g/mol;
the powder silane coupling agent is powdered 3-aminopropyltriethoxysilane, and is prepared by adopting a siliceous inert adsorbent as a carrier to adsorb the powdered 3-aminopropyltriethoxysilane.
2. The lignin-enhanced PE feed water of claim 1The pipe mixes the batching, its characterized in that: the silica inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 0.8-1.2 mu m, the porosity is 65-80%, and the specific surface area is 250-400 m 2 /g。
3. The lignin-enhanced PE water pipe blending stock according to claim 1, wherein: the carbon black has a median particle diameter D50 of less than 25 nm and a specific surface area of 500 m 2 More than g.
4. The lignin-enhanced PE water pipe blending stock according to claim 1, wherein: the compatibilizer is a styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is one or the combination of resorcinol-bis (beta-hydroxyethyl) ether and hydroquinone-bis (beta-hydroxyethyl) ether in any proportion; the antioxidant is prepared by mixing a hindered phenol antioxidant and a phosphite antioxidant according to a mass ratio of 1.5; the lubricant is polyethylene wax with the number average molecular weight of 2000-3000.
5. The method of making the lignin-enhanced PE water pipe furnish of any one of claims 1~4, wherein: the method comprises the following steps:
s1, adding modified lignin into a high-speed mixer, stirring at the speed of 500 r/min, adding a powdery silane coupling agent to mix for 3 min when the temperature reaches 80-110 ℃, then adding a compatibilizer to continue mixing for 5-10 min, then heating to 140 ℃, adding an aromatic diol chain extender to mix for 5min, then sequentially adding carbon black, an antioxidant, a lubricant and resin, and stirring for 10-12 min to obtain a mixed material;
and S2, adding the mixed material obtained in the step S1 into a screw extruder through a feed inlet for processing, and then obtaining the lignin-enhanced PE water supply pipe mixed material through traction, cooling cutting and screening.
6. The method of claim 5, wherein: in step S2, the diameter of a screw in the screw extruder is 71mm, the ratio of screw grooves is 1.5, the depth of the screw groove is 14mm, the length-diameter ratio of the screw is 40/1, the screw is divided into 10 heating zones, and the temperatures of the 10 heating zones from the feed end are 135 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 160 ℃, 150 ℃ and 140 ℃ in sequence; the screw speed was 500rpm.
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