CN114805980B - A kind of lignin reinforced PE water supply pipe compounding material and preparation method thereof - Google Patents

Abstract

The invention discloses a lignin-reinforced PE water supply pipe mixing material, which 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, and 0.5 part of solubilizer ～1.5 parts, 0.5～1.5 parts of carbon black, 0.2～1 part of aromatic diol chain extender, 0.5～1.5 parts of antioxidant, 0.05～0.2 parts of lubricant; the modified lignin is concentrated black liquor Then add hydrogen peroxide, zinc lanthanum niobate, phosphorous acid solution, cationic polyacrylamide solution, etc. for modification treatment in sequence; chain extension of modified lignin, powdered silane coupling agent, compatibilizer, and aromatic diols Agents, carbon black, antioxidants, lubricants and resins are mixed in sequence, and then extruded, drawn, cooled, cut, and screened to obtain lignin-reinforced PE water supply pipe mixes. The invention can effectively improve the composite mechanical strength such as tensile strength and impact strength.

Description

A kind of lignin reinforced PE water supply pipe compounding material and preparation method thereof

technical field

The invention belongs to the technical field of new pipe materials, and in particular relates to a lignin-reinforced PE water supply pipe compounding material and a preparation method thereof.

Background technique

Polyethylene water supply pipe (PE water supply pipe) is the most representative product in plastic pipes, and its promotion and application are on the rise. However, the existing PE water supply pipes have the following deficiencies: 1) The overall external pressure resistance is poor, It is easy to cause pits and perforations when encountering solid stones and metal collisions and extrusions; 2) No flame retardancy; 3) There is a limit to the maximum operating pressure; 4) It is easy to age under the sun and rain, reducing the service life.

In response to the above problems, the current conventional method is to use carbon fibers, plant fibers, synthetic resins and other organic substances to composite PE water supply pipes. For example, the Chinese invention patent application with the application number CN202010404752.X discloses a nano-antibacterial PE water supply pipe and its manufacture. process, the nano antibacterial PE water supply pipeline is composed of a wear-resistant layer, an anti-ultraviolet layer, a thermal insulation layer, an antibacterial layer and an anti-sticking wall layer from the outside to the inside; the nano antibacterial PE water supply pipeline is composed of: 100 parts of polymer 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, 1 ～5 parts of antioxidant; the mass parts of each component in the wear-resistant layer also includes: 1～5 parts of carbon fiber, 1～5 parts of carbon black, 2～5 parts of nano-calcium carbonate, 1～3 parts of anti-oxidant Grinding agent; the mass parts of each component in the antibacterial layer also include: 1-5 parts of nano-silver antibacterial masterbatch, 1-5 parts of surfactant, and 1-5 parts of carrier. Another example is the Chinese invention patent application with the application number CN202111334714.2 disclosing a method for manufacturing a high and low temperature resistant dual-performance hardware sanitary pipe. The high and low temperature resistant dual-performance hardware sanitary pipe includes 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 be boride, carbide, nitride, silicide, One or more mixtures of phosphide and sulfide; the low temperature resistant material is made of polyethylene, polytetrafluoroethylene, polytrifluorochloroethylene, parylene and glass fiber tape bonded with epoxy one or more mixtures.

Lignin is a rich renewable resource, safe and non-toxic, and is a polymer with a three-dimensional network structure formed by rigid phenylpropane structural units connected to each other through C-O and C-C bonds. Existing studies have shown that lignin has a highly cross-linked benzene ring rigid molecular structure, and there are a large number of strong hydrogen bonds between molecules. Dispersed in the PE matrix to form stress concentration points, when the material is subjected to a long-term external force, it can prevent structural damage caused by polymer molecular chain conformation changes or displacement changes, thereby improving the compressive strength and deformation resistance of PE pipes . However, due to the large difference in polarity and poor compatibility between lignin and PE, lignin and PE are prone to agglomeration in the resin continuous phase during blending, which deteriorates the mechanical properties of the prepared composite material and is difficult to achieve. further industrial applications.

Contents of the invention

In view of the above shortcomings, the invention discloses a lignin-reinforced PE water supply pipe compounding material and a preparation method thereof, which can effectively improve the comprehensive mechanical strength such as tensile strength and impact strength of the composite material.

The present invention is realized by adopting the following technical solutions:

A lignin-reinforced PE water supply pipe mixing material, which includes the following components in parts by mass: 100 parts of resin, 2-3 parts of modified lignin, 0.5 part of powdered 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, 0.05-0.2 part of lubricant;

The preparation method of described modified lignin comprises the following steps:

(1) Concentrating the black liquor obtained by alkaline pulping to obtain a concentrated solution with a solid content of 20wt% to 35wt%;

(2) Add hydrogen peroxide and zinc lanthanum niobate in sequence to the concentrated solution obtained in step (1), then stir and react for 90 minutes at 80°C to 85°C with a stirring speed of 300r/min to obtain reaction solution A;

(3) Cool the reaction solution A obtained in step (2) to 45°C-50°C and keep the temperature constant, then pass carbon dioxide gas into the reaction solution A so that the pH value of the reaction solution A reaches 6.0-6.5, and then add Phosphorous acid solution, and stirring and reacting for 20min under the condition that the stirring speed is 300r/min, obtains the reaction solution B;

(4) Cool the reaction B obtained in step (3) to room temperature, then add 2 wt% sulfuric acid to the reaction solution B to make the pH of the reaction solution B reach 2.0-3.0, and then add the cationic polyacrylamide solution , get flocculent precipitate;

(5) Press-filter the flocculent precipitate obtained in step (4) to obtain a filter residue, and then dry the filter residue until the water content is less than 0.5wt% to obtain the modified lignin.

The black liquor is highly concentrated alkaline organic wastewater containing a large amount of organic matter and inorganic salts.

The resin is polyethylene resin, and can be any one of PE125, PE112, PE100 and PE80.

Further, the zinc lanthanum niobate is in lamellar form, and the chemical formula of the zinc lanthanum 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 Any one of O _{and 7} ; the hydrogen peroxide is 30wt% hydrogen peroxide; the cationic polyacrylamide solution is 5wt% cationic polyacrylamide solution; the phosphorous acid solution is 10wt% to 25wt% phosphorous acid aqueous solution.

Further, the volume ratio of the concentrated solution to hydrogen peroxide is (80-800):1; the mass ratio of the concentrated solution to zinc lanthanum niobate is (5-25) L:1g; the concentrated solution and The volume ratio of the phosphorous acid solution is (500-3000):0.1; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is (1000-2500):0.1.

Further, the phenolic hydroxyl content of the modified lignin is greater than 2.5 mmol/g, and the number average molecular weight is less than 11000 g/mol.

Further, the powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent adopts a silicon inert adsorbent as a carrier to absorb powdered 3-aminopropyl made from Triethoxysilane.

Further, the siliceous inert adsorbent is calcium silicate, the calcium silicate has an average pore diameter of 0.8-1.2 μm, a porosity of 65-80%, and a specific surface area of 250-400 m ² /g.

Further, the median particle diameter D50 of the carbon black is less than 25 nm, and the specific surface area is above 500 m ² /g.

Further, the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is resorcinol-bis(β-hydroxyethyl) ether and hydroquinone - one of two (β-hydroxyethyl) ethers or a combination thereof in any proportion; the antioxidant is mixed with a hindered phenolic antioxidant and a phosphite antioxidant according to a mass ratio of 1.5:1; the The lubricant is polyethylene wax, preferably a polyethylene wax with a number average molecular weight of 2000 to 3000.

Technical principle of the present invention is:

Since lignin is a polyphenolic macromolecular compound, a large number of active groups are wrapped inside the molecule, the intermolecular interaction is strong, and the aromatic ring structure is interwoven into a network. Compared with conventional resin fillers such as calcium carbonate and talc, lignin and Conventional surface modifiers such as stearic acid, silanes, and aluminates have poor reactivity. Therefore, the present invention firstly depolymerizes lignin into a series of molecular segments with low molecular weight and polyaldehyde structure by using H ₂ O ₂ as an oxidant and zinc lanthanum niobate as a catalyst under alkaline conditions; After the solution is neutralized, phosphorous acid is used to catalyze the reduction of aldehyde groups to form polyhydroxyl small molecular lignin segments, thereby improving the compatibility of lignin with polymer resins and its compatibility with conventional coupling agents and compatibilizers. Reactivity with the chain extender; at this time, because the lignin segment has a certain water solubility in the neutral solution, it is necessary to further acidify the solution with H ₂ SO ₄ to fully analyze the lignin molecular segment and assist A certain amount of flocculant makes it easier to settle and realize solid-liquid separation.

At the same time, the present invention also selectively adds components such as solubilizers and chain extenders, on the one hand to further improve the compatibility between lignin and polymer resins, on the other hand, the modified lignin obtained by the method of the present invention, its There are a large number of active hydroxyl groups on the molecular chain segment. Adding a suitable reactive chain extender can further increase the binding force between lignin and PE, and part of the remaining active hydroxyl groups that have not reacted with the coupling agent can be passed through The bridging effect of the chain extender connects the PE resin in the form of a chemical bond, thereby improving the comprehensive performance of the composite material.

The preparation method of the above-mentioned lignin-enhanced PE water supply pipe mixing material comprises the following steps:

S1. Add the modified lignin to the high-speed mixer and stir at a speed of 500 r/min. When the temperature reaches 80-110°C, add the powdered silane coupling agent and mix for 3 minutes, then add the compatibilizer and continue mixing 5-10 minutes, then heat up to 140°C, add aromatic diol chain extender and mix for 5 minutes, then add carbon black, antioxidant, lubricant and resin in sequence, and stir for 10-12 minutes to obtain the mixed material;

S2. Add the mixed material obtained in step S1 into the screw extruder through the feed port for processing, and obtain the lignin-reinforced PE water supply pipe mixed material after traction, cooling, cutting and screening.

Further, in step S2, the screw diameter in the screw extruder is 71 mm, the screw groove ratio is 1.5, the screw groove depth is 14 mm, the screw length-to-diameter ratio is 40/1, and the screw is divided into 10 heating zones. The temperature of the 10 heating zones starting from the feed end is 135°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 160°C, 150°C, 140°C; the screw speed is 500rpm.

Compared with the prior art, this technical solution has the following beneficial effects:

1. Conventional lignin catalytic oxidation generally needs to be reacted at over 200°C for more than 2~5h to obtain better products. The present invention adopts a low-temperature alkaline oxidation method, using H ₂ O ₂ as an oxidant, and zinc lanthanum niobate as a catalyst, and reacting at 80°C to 85°C for 20 minutes can obtain low-molecular-weight, high-activity lignin molecular segments; at the same time , compared with unmodified lignin macromolecules, the polyhydroxy lignin molecular segments obtained in the present invention are more likely to react with silane coupling agents, compatibilizers and chain extenders, showing more excellent thermal fluidity, resin compatibility and reactivity.

2. The present invention directly uses alkaline pulping black liquor as a raw material source, which can reduce the pollution of black liquor to the environment, and realizes the resource recycling and utilization of lignin; at the same time, the present invention uses carbon dioxide as an acidic reagent to neutralize the reaction system Alkalinity, while saving acid, also achieves the purpose of carbon neutrality to a certain extent.

3. The present invention uses a powdery coupling agent as a hydrophobic modifier of lignin, which can effectively improve the problem of uneven dispersion of liquid silane coupling agents on lignin molecules, thereby improving the hydrophobicity of lignin. degree of modification. At the same time, by adding the reactive compatibilizer PS-co-GMA with benzene ring structure, the interfacial compatibility between lignin with phenylpropane as the basic structural unit and PE resin can be improved, and by increasing the reactive aromatic The family diol chain extender can link the active hydroxyl group in the lignin molecular chain segment with the PE resin, thereby effectively improving the comprehensive mechanical strength of the composite material such as tensile strength and impact strength.

Description of drawings

FIG. 1 is an SEM image of the modified lignin obtained in Example 1.

Fig. 2 is a GPC graph 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 diagram 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. 4 is an SEM image of the brittle section of the mixed material sample prepared according to the method described in Example 1 in the experimental example.

Fig. 5 is an SEM image of the brittle section of the mixed material sample prepared according to the method described in Comparative Example 1 in the experimental example.

Fig. 6 is the tensile strength-elongation at break test curve figure of the compound sample prepared according to the method described in embodiment 1, comparative example 1 and comparative example 9 in the experimental example, wherein curve 1 represents that in embodiment 1 Mixed material spline, curve 2 represents the mixed material spline in comparative example 1, and curve 3 represents the mixed material spline in comparative example 9.

Detailed ways

The present invention is further illustrated by the following examples, but not as a limitation of the present invention. For the specific experimental conditions and methods not indicated in the following examples, the technical means used are generally conventional means well known to those skilled in the art.

Example 1:

A lignin-reinforced PE water supply pipe compounding material, which includes the following components in parts by mass: 100 parts of resin, 2 parts of modified lignin, 0.5 part of powdered silane coupling agent, 0.85 part of solubilizer, and 0.75 part of carbon black , 0.8 part of aromatic diol chain extender, 1.0 part of antioxidant, 0.15 part of lubricant; the black liquor is alkaline organic wastewater with high concentration, containing a large amount of organic matter and inorganic salts; the resin is PE125 ; The powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent adopts a silicon inert adsorbent as a carrier to absorb powdered 3-aminopropyltriethoxysilane ethoxysilane; the siliceous inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 1.02 μm, the porosity is 72.3%, and the specific surface area is 287.1 m ² /g; The median particle size D50 of carbon black is 20 nm, and the specific surface area is 1200m ² /g; the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is Resorcinol-bis(β-hydroxyethyl) ether and hydroquinone-bis(β-hydroxyethyl) ether are obtained by mixing according to the mass ratio of 7:3; the antioxidant is hindered phenolic antioxidant and The phosphite antioxidant is mixed according to the mass ratio of 1.5:1; the lubricant is a polyethylene wax with a number average molecular weight of 3000;

The preparation method of described modified lignin comprises the following steps:

(1) Concentrating the black liquor obtained by alkaline pulping to obtain a concentrated solution with a solid content of 30wt%;

(2) Add hydrogen peroxide and zinc lanthanum niobate successively to the concentrated solution obtained in step (1), then stir and react at 82°C and a stirring speed of 300r/min for 90min to obtain reaction solution A; the lanthanum niobium Zinc acid is lamellar, and the chemical formula of zinc lanthanum niobate is Zn _1/2 LaNb ₂ O ₇ ; the hydrogen peroxide is 30wt% hydrogen peroxide; the volume ratio of the concentrate to hydrogen peroxide is 1000:5; The volume of described concentrate and the mass ratio of zinc lanthanum niobate are 1000L:75g;

(3) Cool the reaction solution A obtained in step (2) to 45°C and keep the temperature constant, then pass carbon dioxide gas into the reaction solution A, so that the pH value of the reaction solution A reaches 6.2, and then add the phosphorous acid solution, and Stirring and reacting for 20 minutes at a stirring speed of 300r/min to obtain a reaction solution B; the volume ratio of the concentrated solution to the phosphorous acid solution is 1000:0.1; the phosphorous acid solution is a 20wt% phosphorous acid aqueous solution;

(4) Cool the reaction B obtained in step (3) to room temperature, then add 2 wt% sulfuric acid to the reaction solution B, so that the pH value of the reaction solution B reaches 2.5, and then add the cationic polyacrylamide solution to obtain Flocculent precipitates; the cationic polyacrylamide solution is a 5wt% cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 1000:0.08;

(5) Press-filter the flocculent precipitate obtained in step (4) to obtain a filter residue, and then dry 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 described in this embodiment comprises the following steps:

S1. Add the modified lignin to the high-speed mixer and stir at a speed of 500 r/min. When the temperature reaches 105°C, add powdered silane coupling agent and mix for 3 minutes, then add compatibilizer and continue mixing for 5 minutes. Then heat up to 140°C, add aromatic diol chain extender and mix for 5 minutes, then add carbon black, antioxidant, lubricant and resin in sequence, and stir for 11 minutes to obtain the mixed material;

S2. Add the mixed material obtained in step S1 to the screw extruder through the feed port for processing, and obtain lignin-enhanced PE water supply pipe mixed ingredients after traction, cooling, cutting, and screening; the screw extruder The diameter of the middle screw is 71mm, the ratio of the screw groove is 1.5, the depth of the screw groove is 14mm, the ratio of length to diameter of the screw is 40/1, the screw is divided into 10 heating zones, and the temperature of the 10 heating zones starting from the feed end is 135°C , 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 160°C, 150°C, 140°C; the screw speed is 500rpm.

Example 2:

A lignin-reinforced PE water supply pipe compounding material, which includes the following components in parts by mass: 100 parts of resin, 3 parts of modified lignin, 0.5 part of powdered silane coupling agent, 0.5 part of solubilizer, and 0.85 part of carbon black , 0.3 parts of aromatic diol chain extenders, 1.0 parts of antioxidants, and 0.1 parts of lubricants; the black liquor is high-concentration alkaline organic wastewater containing a large amount of organic matter and inorganic salts; the resin is PE100 ; The powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent adopts a silicon inert adsorbent as a carrier to absorb powdered 3-aminopropyltriethoxysilane ethoxysilane; the siliceous inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 1.2 μm, the porosity is 68.8%, and the specific surface area is 205.0 m ² /g; The median particle size D50 of carbon black is 25 nm, and the specific surface area is 925.3 m ² /g; the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender It is obtained by mixing resorcinol-bis(β-hydroxyethyl) ether and hydroquinone-bis(β-hydroxyethyl) ether according to the mass ratio of 1:1; the antioxidant is hindered phenolic antioxidant It is mixed with a phosphite antioxidant according to a mass ratio of 1.5:1; the lubricant is a polyethylene wax with a number average molecular weight of 3000;

The preparation method of described modified lignin comprises the following steps:

(1) Concentrating the black liquor obtained by alkaline pulping to obtain a concentrated solution with a solid content of 35wt%;

(2) Add hydrogen peroxide and zinc lanthanum niobate successively to the concentrated solution obtained in step (1), then stir and react at 80°C and a stirring speed of 300r/min for 90min to obtain reaction solution A; the lanthanum niobium Zinc acid is lamellar, and the chemical formula of zinc lanthanum niobate is ZnLa _2/3 Nb ₂ O ₇ ; the hydrogen peroxide is 30wt% hydrogen peroxide; the volume ratio of the concentrate to hydrogen peroxide is 1200:4; The volume of described concentrate and the mass ratio of zinc lanthanum niobate are 1200L: 50g;

(3) Cool the reaction solution A obtained in step (2) to 45°C-50°C and keep the temperature constant, then pass carbon dioxide gas into the reaction solution A so that the pH value of the reaction solution A reaches 6.0-6.5, and then add Phosphorous acid solution, and stirring reaction 20min under the condition of 300r/min at stirring speed, obtain reaction solution B; The volume ratio of described concentrated solution and phosphorous acid solution is 1200:0.12; Described phosphorous acid solution is the phosphorous acid solution of 25wt%. Phosphoric acid aqueous solution;

(4) Cool the reaction B obtained in step (3) to room temperature, then add 2 wt% sulfuric acid to the reaction solution B, so that the pH value of the reaction solution B reaches 3.0, and then add the cationic polyacrylamide solution to obtain Flocculent precipitate; the cationic polyacrylamide solution is a 5wt% cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 1200:0.08;

(5) Press-filter the flocculent precipitate obtained in step (4) to obtain a filter residue, and then dry 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 described in this embodiment comprises the following steps:

S1. Add the modified lignin to the high-speed mixer and stir at a speed of 500 r/min. When the temperature reaches 110°C, add powdered silane coupling agent and mix for 3 minutes, then add compatibilizer and continue mixing for 7 minutes. Then heat up to 140°C, add aromatic diol chain extender and mix for 5 minutes, then add carbon black, antioxidant, lubricant and resin in sequence, and stir for 10.5 minutes to obtain the mixed material;

S2. Add the mixed material obtained in step S1 to the screw extruder through the feed port for processing, and obtain lignin-enhanced PE water supply pipe mixed ingredients after traction, cooling, cutting, and screening; the screw extruder The diameter of the middle screw is 71mm, the ratio of the screw groove is 1.5, the depth of the screw groove is 14mm, the ratio of length to diameter of the screw is 40/1, the screw is divided into 10 heating zones, and the temperature of the 10 heating zones starting from the feed end is 135°C , 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 160°C, 150°C, 140°C; the screw speed is 500rpm.

Example 3:

A lignin-reinforced PE water supply pipe compounding material, which includes the following components in parts by mass: 100 parts of resin, 2 parts of modified lignin, 0.5 part of powdered silane coupling agent, 0.9 part of solubilizer, and 1.25 parts of carbon black , 0.2 part of aromatic diol chain extender, 1.25 part of antioxidant, 0.2 part of lubricant; the black liquor is alkaline organic wastewater with high concentration, containing a large amount of organic matter and inorganic salts; the resin is PE112 ; The powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent adopts a silicon inert adsorbent as a carrier to absorb powdered 3-aminopropyltriethoxysilane ethoxysilane; the siliceous inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 0.8 μm, the porosity is 80%, and the specific surface area is 289.36m ² /g; The median particle size D50 of carbon black is 10 nm, and the specific surface area is 800 m ² /g; the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender It is obtained by mixing resorcinol-bis(β-hydroxyethyl) ether and hydroquinone-bis(β-hydroxyethyl) ether according to the mass ratio of 1:4; the antioxidant is hindered phenolic antioxidant It is mixed with a phosphite antioxidant according to a mass ratio of 1.5:1; the lubricant is a polyethylene wax with a number average molecular weight of 3000;

The preparation method of described modified lignin comprises the following steps:

(1) Concentrating the black liquor obtained by alkaline pulping to obtain a concentrated solution with a solid content of 35wt%;

(2) Add hydrogen peroxide and zinc lanthanum niobate successively to the concentrated solution obtained in step (1), then stir and react at 80°C and a stirring speed of 300r/min for 90min to obtain reaction solution A; the lanthanum niobium Zinc acid is lamellar, and the chemical formula of zinc lanthanum niobate is Zn _1.5 La _1/3 Nb ₂ O ₇ ; the hydrogen peroxide is 30wt% hydrogen peroxide; the volume ratio of the concentrate to hydrogen peroxide is 80:1 ; The volume of the concentrate and the mass ratio of zinc lanthanum niobate are 800L: 150g;

(3) Cool the reaction solution A obtained in step (2) to 50°C and then keep the temperature constant, then pass carbon dioxide gas into the reaction solution A, so that the pH value of the reaction solution A reaches 6.0, and then add the phosphorous acid solution, and Stirring and reacting for 20min at a stirring speed of 300r/min to obtain a reaction solution B; the volume ratio of the concentrated solution to the phosphorous acid solution is 800:0.03; the phosphorous acid solution is a 10wt% phosphorous acid aqueous solution;

(4) Cool the reaction B obtained in step (3) to room temperature, then add 2 wt% sulfuric acid to the reaction solution B, so that the pH value of the reaction solution B reaches 2.0, and then add the cationic polyacrylamide solution to obtain Flocculent precipitate; the cationic polyacrylamide solution is a 5wt% cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 800:0.08;

(5) Press-filter the flocculent precipitate obtained in step (4) to obtain a filter residue, and then dry 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 described in this embodiment comprises the following steps:

S1. Add the modified lignin to the high-speed mixer and stir at a speed of 500 r/min. When the temperature reaches 95°C, add the powdered silane coupling agent and mix for 3 minutes, then add the compatibilizer and continue mixing for 10 minutes. Then heat up to 140°C, add aromatic diol chain extender and mix for 5 minutes, then add carbon black, antioxidant, lubricant and resin in sequence, and stir for 10 minutes to obtain the mixed material;

S2. Add the mixed material obtained in step S1 to the screw extruder through the feed port for processing, and obtain lignin-enhanced PE water supply pipe mixed ingredients after traction, cooling, cutting, and screening; the screw extruder The diameter of the middle screw is 71mm, the ratio of the screw groove is 1.5, the depth of the screw groove is 14mm, the ratio of length to diameter of the screw is 40/1, the screw is divided into 10 heating zones, and the temperature of the 10 heating zones starting from the feed end is 135°C , 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 160°C, 150°C, 140°C; the screw speed is 500rpm.

Example 4:

A lignin-reinforced PE water supply pipe mixing material, which includes the following components in parts by mass: 100 parts of resin, 2.5 parts of modified lignin, 0.5 part of powdered silane coupling agent, 1 part of solubilizer, and 0.5 part of carbon black , 0.35 parts of aromatic diol chain extenders, 1.0 parts of antioxidants, and 0.18 parts of lubricants; the black liquor is high-concentration alkaline organic wastewater containing a large amount of organic matter and inorganic salts; the resin is PE80 ; The powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent adopts a silicon inert adsorbent as a carrier to absorb powdered 3-aminopropyltriethoxysilane ethoxysilane; the siliceous inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 1.0 μm, the porosity is 65%, and the specific surface area is 351.15m ² /g; The median particle diameter D50 of the carbon black is 18nm, and the specific surface area is 750 m ² /g; the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender is Resorcinol-bis(β-hydroxyethyl) ether and hydroquinone-bis(β-hydroxyethyl) ether are obtained by mixing according to the mass ratio of 1:2; the antioxidant is hindered phenolic antioxidant and The phosphite antioxidant is mixed according to the mass ratio of 1.5:1; the lubricant is a polyethylene wax with a number average molecular weight of 2000;

The preparation method of described modified lignin comprises the following steps:

(1) Concentrating the black liquor obtained by alkaline pulping to obtain a concentrated solution with a solid content of 28wt%;

(2) Add hydrogen peroxide and zinc lanthanum niobate successively to the concentrated solution obtained in step (1), then stir and react at 84°C and a stirring speed of 300r/min for 90min to obtain reaction solution A; the lanthanum niobium Zinc acid is lamellar, and the chemical formula of zinc lanthanum niobate is Zn _1/2 LaNb ₂ O ₇ ; the hydrogen peroxide is 30wt% hydrogen peroxide; the volume ratio of the concentrate to hydrogen peroxide is 1800:3; The volume of described concentrate and the mass ratio of zinc lanthanum niobate are 1800L:200g;

(3) Cool the reaction solution A obtained in step (2) to 458°C and then keep the temperature constant, then pass carbon dioxide gas into the reaction solution A, so that the pH value of the reaction solution A reaches 6.5, and then add the phosphorous acid solution, and Stirring and reacting for 20min at a stirring speed of 300r/min to obtain a reaction solution B; the volume ratio of the concentrated solution to the phosphorous acid solution is 1800:0.25; the phosphorous acid solution is a 12wt% phosphorous acid aqueous solution;

(4) Cool the reaction B obtained in step (3) to room temperature, then add 2 wt% sulfuric acid to the reaction solution B, so that the pH value of the reaction solution B reaches 2.5, and then add the cationic polyacrylamide solution to obtain Flocculent precipitate; the cationic polyacrylamide solution is a 5wt% cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 1800:0.08;

(5) Press-filter the flocculent precipitate obtained in step (4) to obtain a filter residue, and then dry 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 described in this embodiment comprises the following steps:

S1. Add the modified lignin to the high-speed mixer and stir at a speed of 500 r/min. When the temperature reaches 102°C, add powdered silane coupling agent and mix for 3 minutes, then add compatibilizer and continue mixing for 8 minutes. Then heat up to 140°C, add aromatic diol chain extender and mix for 5 minutes, then add carbon black, antioxidant, lubricant and resin in sequence, and stir for 12 minutes to obtain the mixed material;

S2. Add the mixed material obtained in step S1 to the screw extruder through the feed port for processing, and obtain lignin-enhanced PE water supply pipe mixed ingredients after traction, cooling, cutting, and screening; the screw extruder The diameter of the middle screw is 71mm, the ratio of the screw groove is 1.5, the depth of the screw groove is 14mm, the ratio of length to diameter of the screw is 40/1, the screw is divided into 10 heating zones, and the temperature of the 10 heating zones starting from the feed end is 135°C , 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 160°C, 150°C, 140°C; the screw speed is 500rpm.

Example 5:

A lignin-reinforced PE water supply pipe compound, which includes the following components in parts by mass: 100 parts of resin, 2 parts of modified lignin, 0.5 part of powdered silane coupling agent, 0.5 part of solubilizer, and 0.5 part of carbon black , 0.2 parts of aromatic diol chain extenders, 0.5 parts of antioxidants, and 0.05 parts of lubricants; the black liquor is high-concentration alkaline organic wastewater containing a large amount of organic matter and inorganic salts; the resin is PE100 ; The powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent adopts a silicon inert adsorbent as a carrier to absorb powdered 3-aminopropyltriethoxysilane ethoxysilane; the siliceous inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 0.8 μm, the porosity is 65%, and the specific surface area is 250 m ² /g; The median particle size D50 of carbon black is 25 nm, and the specific surface area is 500 m ² /g; the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender It is resorcinol-bis(β-hydroxyethyl) ether; the antioxidant is a mixture of hindered phenolic antioxidant and phosphite antioxidant according to the mass ratio of 1.5:1; the lubricant is Polyethylene wax with a number average molecular weight of 2500;

The preparation method of described modified lignin comprises the following steps:

(1) Concentrating the black liquor obtained by alkaline pulping to obtain a concentrated solution with a solid content of 20wt%;

(2) Add hydrogen peroxide and zinc lanthanum niobate successively to the concentrated solution obtained in step (1), then stir and react at 80°C and a stirring speed of 300r/min for 90min to obtain reaction solution A; the lanthanum niobium Zinc acid is lamellar, and the chemical formula of zinc lanthanum niobate is Zn _1/2 LaNb ₂ O ₇ ; the hydrogen peroxide is 30wt% hydrogen peroxide; the volume ratio of the concentrated solution to hydrogen peroxide is 80:1; The volume of said concentrate and the mass ratio of zinc lanthanum niobate are 5L:1g;

(3) Cool the reaction solution A obtained in step (2) to 45°C and keep the temperature, then pass carbon dioxide gas into the reaction solution A, so that the pH value of the reaction solution A reaches 6.0, and then add the phosphorous acid solution, and Stirring and reacting for 20min at a stirring speed of 300r/min to obtain a reaction solution B; the volume ratio of the concentrated solution to the phosphorous acid solution is 500:0.1; the phosphorous acid solution is a 10wt% phosphorous acid aqueous solution;

(4) Cool the reaction B obtained in step (3) to room temperature, then add 2 wt% sulfuric acid to the reaction solution B, so that the pH value of the reaction solution B reaches 2.0, and then add the cationic polyacrylamide solution to obtain Flocculent precipitate; the cationic polyacrylamide solution is a 5wt% cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 1000:0.1;

(5) Press-filter the flocculent precipitate obtained in step (4) to obtain a filter residue, and then dry 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 described in this embodiment comprises the following steps:

S1. Add the modified lignin to the high-speed mixer and stir at a speed of 500 r/min. When the temperature reaches 80°C, add powdered silane coupling agent and mix for 3 minutes, then add compatibilizer and continue mixing for 5 minutes. Then heat up to 140°C, add aromatic diol chain extender and mix for 5 minutes, then add carbon black, antioxidant, lubricant and resin in sequence, and stir for 10 minutes to obtain the mixed material;

S2. Add the mixed material obtained in step S1 to the screw extruder through the feed port for processing, and obtain lignin-enhanced PE water supply pipe mixed ingredients after traction, cooling, cutting, and screening; the screw extruder The diameter of the middle screw is 71mm, the ratio of the screw groove is 1.5, the depth of the screw groove is 14mm, the ratio of length to diameter of the screw is 40/1, the screw is divided into 10 heating zones, and the temperature of the 10 heating zones starting from the feed end is 135°C , 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 160°C, 150°C, 140°C; the screw speed is 500rpm.

Embodiment 6:

A lignin-reinforced PE water supply pipe compounding material, which includes the following components in parts by mass: 100 parts of resin, 3 parts of modified lignin, 0.5 parts of powdered silane coupling agent, 1.5 parts of solubilizer, and 1.5 parts of carbon black , 1 part of aromatic diol chain extender, 1.5 parts of antioxidant, 0.2 part of lubricant; the black liquor is alkaline organic wastewater with high concentration, containing a large amount of organic matter and inorganic salts; the resin is PE80 ; The powdered silane coupling agent is powdered 3-aminopropyltriethoxysilane, and the powdered coupling agent adopts a silicon inert adsorbent as a carrier to absorb powdered 3-aminopropyltriethoxysilane ethoxysilane; the siliceous inert adsorbent is calcium silicate, the average pore diameter of the calcium silicate is 1.2 μm, the porosity is 80%, and the specific surface area is 400 m ² /g; The median particle diameter D50 of carbon black is 10 nm, and the specific surface area is 500 m ² /g; the compatibilizer is styrene-glycidyl methacrylate copolymer; the aromatic diol chain extender It is hydroquinone-bis(β-hydroxyethyl) ether; the antioxidant is a mixture of hindered phenolic antioxidant and phosphite antioxidant according to the mass ratio of 1.5:1; the lubricant is a number average Polyethylene wax with a molecular weight of 2500;

The preparation method of described modified lignin comprises the following steps:

(1) Concentrating the black liquor obtained by alkaline pulping to obtain a concentrated solution with a solid content of 35wt%;

(2) Add hydrogen peroxide and zinc lanthanum niobate sequentially to the concentrated solution obtained in step (1), then stir and react at 85°C and a stirring speed of 300r/min for 90min to obtain reaction solution A; the lanthanum niobium Zinc acid is lamellar, and the chemical formula of zinc lanthanum niobate is ZnLa _2/3 Nb ₂ O ₇ ; the hydrogen peroxide is 30wt% hydrogen peroxide; the volume ratio of the concentrate to hydrogen peroxide is 800:1; The volume of said concentrate and the mass ratio of zinc lanthanum niobate are 25L:1g;

(3) Cool the reaction solution A obtained in step (2) to 45°C-50°C and keep the temperature constant, then pass carbon dioxide gas into the reaction solution A so that the pH value of the reaction solution A reaches 6.0-6.5, and then add Phosphorous acid solution, and stirring reaction 20min under the condition of 300r/min at stirring speed, obtains reaction solution B; The volume ratio of described concentrated solution and phosphorous acid solution is 3000:0.1; Described phosphorous acid solution is the phosphorous acid solution of 25wt%. Phosphoric acid aqueous solution;

(4) Cool the reaction B obtained in step (3) to room temperature, then add 2 wt% sulfuric acid to the reaction solution B, so that the pH value of the reaction solution B reaches 3.0, and then add the cationic polyacrylamide solution to obtain Flocculent precipitate; the cationic polyacrylamide solution is 5wt% cationic polyacrylamide solution; the volume ratio of the concentrated solution to the cationic polyacrylamide solution is 2500:0.1;

(5) Press-filter the flocculent precipitate obtained in step (4) to obtain a filter residue, and then dry 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 described in this embodiment comprises the following steps:

S1. Add the modified lignin to the high-speed mixer and stir at a speed of 500 r/min. When the temperature reaches 110°C, add powdered silane coupling agent and mix for 3 minutes, then add compatibilizer and continue mixing for 10 minutes. Then heat up to 140°C, add aromatic diol chain extender and mix for 5 minutes, then add carbon black, antioxidant, lubricant and resin in sequence, and stir for 12 minutes to obtain the mixed material;

S2. Add the mixed material obtained in step S1 to the screw extruder through the feed port for processing, and obtain lignin-enhanced PE water supply pipe mixed ingredients after traction, cooling, cutting, and screening; the screw extruder The diameter of the middle screw is 71mm, the ratio of the screw groove is 1.5, the depth of the screw groove is 14mm, the ratio of length to diameter of the screw is 40/1, the screw is divided into 10 heating zones, and the temperature of the 10 heating zones starting from the feed end is 135°C , 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 160°C, 150°C, 140°C; the screw speed is 500rpm.

Comparative example 1:

The difference between this comparative example and the lignin-enhanced PE water supply pipe mixing material described in Example 1 is that the original lignin is replaced with modified lignin, and the original lignin is prepared by making alkaline pulping black liquor Concentrate to a concentrated solution with a solid content of 30 wt%, then take 1000L of the concentrated solution, add 72 wt% _H2SO4 solution under _stirring conditions, and make the pH of the solution reach 2~3 to form a large number of flocculent precipitates, fully After standing still, the solid-liquid separation is realized by plate and frame filtration, and the obtained solid is washed with a large amount of deionized water until the washing liquid is neutral, and then vacuum-dried at 60°C until the water content is less than 0.5wt%, that is, the log The preparation method of the lignin-enhanced PE water supply pipe compound is consistent with the method described in Example 1.

Comparative example 2:

The difference between this comparative example and the lignin-reinforced PE water supply pipe compound described in Example 1 is that the powder silane coupling agent is not used, and the other steps are consistent with the method described in Example 1.

Comparative example 3:

The only difference between this comparative example and the lignin-enhanced PE water supply pipe mixture described in Example 1 is that the powdered silane coupling agent is only powdered 3-aminopropyltriethoxysilane, and no silicic acid is used. Calcium is adsorbed, and other steps are consistent with the method described in Example 1.

Comparative example 4:

The difference between this comparative example and the lignin-reinforced PE water supply pipe compound described in Example 1 is that the solubilizer is not used, and the other steps are consistent with the method described in Example 1.

Comparative example 5:

The difference between this comparative example and the lignin-reinforced PE water supply pipe mixture described in Example 1 is that the solubilizer is PE-g-MAH, and the other steps are consistent with the method described in Example 1.

Comparative example 6:

The difference between this comparative example and the lignin-reinforced PE water supply pipe compound described in Example 1 is that the chain extender is not used, and the other steps are consistent with the method described in Example 1.

Comparative example 7:

The difference between this comparative example and the lignin-reinforced PE water supply pipe compound described in Example 1 is that the chain extender is Joncryl ADR 4370F, and the other steps are the same as those described in Example 1.

Comparative example 8:

The difference between this comparative example and the lignin-reinforced PE water supply pipe compound described in Example 1 is that no zinc lanthanum niobate was added when preparing the modified lignin, and the other steps were consistent with the method described in Example 1.

Comparative example 9:

The difference between this comparative example and the lignin-reinforced PE water supply pipe mixture described in Example 1 is that no modified lignin is added, and the other steps are consistent with the method described in Example 1.

Experimental example:

The modified lignin and the mixed ingredients were prepared according to the methods described in Examples 1-6 and Comparative Examples 1-9, and then tested according to the following method. See Table 1 and Table 2 for the test results.

(1) Determination of lignin structure:

木质素的酚羟基含量根据以下文献内容进行测定：吴保国，赵菊兰，杜晶滨.差示紫外光谱法测定木素酚羟基含量[J]. 东北林业大学学报，1993，02（21），58~65 。

The phenolic hydroxyl content of lignin was determined according to the following literature: Wu Baoguo, Zhao Julan, Du Jingbin. Determination of lignin phenolic hydroxyl content by differential ultraviolet spectroscopy [J]. Journal of Northeast Forestry University, 1993, 02 (21), 58~65.

木质素的分子量和分子量分布采用Waters 1515/2414凝胶渗透色谱仪测定，测试柱温保持40℃，1 ml/min的流速，以三根Waters的色谱柱串联（Styragel HR1、HR3和HR4），DMF作流动相，德国PSS的聚苯乙烯为标样(Mp= 246000，184000，120000，44200,18200, 9890, 6520, 2770, 890, 474, 370，PDI＜1.20)。

The molecular weight and molecular weight distribution of lignin were measured by Waters 1515/2414 gel permeation chromatography, the test column temperature was kept at 40°C, the flow rate was 1 ml/min, three Waters chromatographic columns were connected in series (Styragel HR1, HR3 and HR4), DMF As the mobile phase, the polystyrene of PSS in Germany was used as the standard sample (Mp= 246000, 184000, 120000, 44200, 18200, 9890, 6520, 2770, 890, 474, 370, PDI<1.20).

木质素的玻璃化转变温度采用TA 公司的Q20差示扫描量热法测定，测试在N₂氛围中，以10 ℃/min的升温速度进行。

The glass transition temperature of lignin was measured by Q20 differential scanning calorimetry of TA Company, and the test was carried out in N ₂ atmosphere at a heating rate of 10 ℃/min.

1H-NMR测试是将2~3 mg BL溶于10 ml DMSO-d6后取清澈的上层溶液，通过美国Agilent 800MHz核磁共振波谱仪进行。

1H-NMR test is to dissolve 2~3 mg BL in 10 ml DMSO-d6 and take the clear upper layer solution, which is carried out by American Agilent 800MHz nuclear magnetic resonance spectrometer.

(2) Performance measurement of the mixed ingredients: the obtained mixed ingredients were injection molded by an injection molding machine under the conditions of 170° C. and 45 MPa to make dumbbell-shaped standard tensile test specimens. The tensile strength and elongation at break were tested by an electronic universal testing machine, and the impact strength was tested by a cantilever beam impact tester. Test conditions: Tensile strength and elongation at break are tested according to the standard GB/T 1040.2-2006; impact strength is tested according to the standard GB/T 1043.1-2008; the obtained compound is made into PE with specifications of DN110 and SDR17 through a pipeline extruder For the water supply pipe, the hydrostatic strength, oxidation induction time and longitudinal retraction rate of the product are measured according to the national standard GB/T13663-2018.

Table 1 Determination results of lignin prepared by different methods

Table 2 Performance test results of large-diameter polyethylene water supply pipes prepared by different methods

As can be seen from Table 1, in comparative example 1, the lignin that the papermaking black liquor that 1000L solid content is 30wt% reclaims is 188.60 Kg, and the yield of its phenolic hydroxyl content is 2.45 mmol/g; And embodiment 1～ The lignin recovered from 1000L papermaking black liquor with a solid content of 30wt% in 6 is more than 190 Kg, and its phenolic hydroxyl content is more than 2.5 mmol/g. It shows that after the low-temperature oxidation-phosphorous acid reduction-acid flocculation treatment of the present invention, the number of active hydroxyl groups in the lignin molecular chain segment can be effectively increased, and then it is easier to react with the silane coupling agent, compatibilizer and chain extender. Simultaneously, the lignin in the papermaking black liquor is composed of acid-soluble lignin and acid-insoluble lignin. Compared with Comparative Example 1, the present invention obtains a higher yield of lignin, indicating that the low-temperature oxidation-phosphorous acid reduction of the present invention - After acid flocculation treatment, it can promote the transformation of part of acid-soluble lignin into acid-insoluble lignin, and then form precipitation.

As can be seen from Table 2, on the proportioning of materials in Example 1, whether it is to remove the compatibilizer or chain extender or zinc lanthanum niobate catalyst, or replace the present invention with conventional PE-g-MAH compatibilizer The required styrene-glycidyl methacrylate copolymer (PS-co-GMA) compatibilizer, or replace the resorcinol-bis(β -Hydroxyethyl) ether/hydroquinone-bis(β-hydroxyethyl)ether mixed chain extender, the obtained lignin-PE composites have mechanical properties such as tensile strength, elongation at break and impact strength. It shows that the modified lignin obtained by the technology of the present invention can play a synergistic effect with the compatibilizer and chain extender required by the technology of the present invention, thereby obtaining better comprehensive performance.

At the same time, it can be seen from Figure 1 that after the low-temperature oxidation-phosphorous acid reduction-acid flocculation treatment of the present invention, the original lignin particles are disintegrated into many fine particles of different sizes, and the particle size is about 1.0-2 μm.

It can be seen from Figure 2 that the GPC spectrum of the original lignin (Comparative Example 1) is not a single peak, but a continuous distribution of double peaks, respectively, the number average molecular weight is 107106 g/mol, and the molecular weight distribution (PDI=2.159 ) and the number average molecular weight of 11270g/mol, and the distribution peak of the molecular weight distribution (PDI=1.371), indicating that the molecular weight distribution of the original lignin (Comparative Example 1) is relatively wide, and there are large differences between molecules. After the low-temperature oxidation-phosphorous acid reduction-acid flocculation treatment of the present invention, the GPC spectrogram of the obtained modified lignin presents a single distribution peak, and the number average molecular weight and molecular weight distribution are 4897 g/mol and 1.360 respectively, illustrating the present invention Technical treatment can effectively reduce the molecular weight of lignin and form more small molecular lignin segments.

Since lignin is an amorphous thermoplastic polymer, it has no melting point, but has a glass transition property. Under a certain pressure, it will soften and have fluidity and adhesiveness, so the glass transition temperature of lignin (Tg) is a key factor affecting the processing performance of lignin-PE. It can be seen from Figure 3 that the glass transition temperature of the original lignin (Comparative Example 1) is 138.1°C. The lower temperature is 128.3°C, which shows that the technical treatment of the present invention can effectively reduce the glass transition temperature of lignin, increase the fluidity of composite materials at lower temperatures, and facilitate the processing and molding of composite materials.

It can be seen from Figure 4 and Figure 5 that in Comparative Example 1 (Figure 5), the lignin was hard granular and agglomerated, and there was an interface difference between it and the PE matrix resin, and the gap between them was obvious, indicating that the log The compatibility between quality and PE resin is poor, and it is difficult to obtain a continuous and uniform composite material through melt extrusion alone. However, in the lignin-PE composite material obtained in Example 1 (Figure 4), the lignin and the PE matrix resin are almost integrated, and no obvious gaps or holes can be observed between each other, which shows that the technology of the present invention can be processed. Effectively improve the compatibility of lignin and PE resin.

It can be seen from Figure 6 that the tensile strength and elongation at break of PE are 24.35 MPa and 1736.27% respectively; while the tensile strength and elongation at break of the composite material directly blended with raw lignin (Comparative Example 1) The elongation ratios are 14.39MPa and 588.38%, respectively, indicating that the composite material obtained by direct blending of raw lignin and PE has phase defects, which tend to become fracture points when stressed, thereby reducing the mechanical properties of the composite material. The tensile strength and elongation at break of the lignin-PE composite material obtained in Example 1 are 32.49 MPa and 1834.36%, respectively, which are greatly improved compared with PE, indicating that the composite material obtained by the technology of the present invention can effectively increase PE. Comprehensive properties such as tensile strength and elongation at break.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be 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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