Self-adaptive strong-anchoring phosphorus-free physical stripping descaling polymer and preparation method thereof

Abstract

The invention relates to a self-adaptive strong-anchoring phosphorus-free physical stripping descaling polymer and a preparation method thereof, and belongs to the technical field of industrial cleaning materials, the self-adaptive strong-anchoring phosphorus-free physical stripping descaling polymer is a copolymer with an A-B-C type triblock structure as shown in a formula (I): [A] m-[B] n-[C] p-(I), the block A is a phosphorus-free rigid anchoring block and is formed by polymerizing monomers selected from a formula (II) or a formula (III), and the block B is a phosphorus-free rigid anchoring block and is formed by polymerizing monomers selected from a formula (II) or a formula (III); formula (II): CH = CR-COO-(CH) q-Ar-(COOH) r; formula (III): CH = CR-CONH-(CH) s-crown ether group; the block B is a pH-responsive intelligent block and is formed by polymerizing a vinyl monomer containing tertiary amino, and the polymerization degree n is 10-100; the block C is a flexible traction block and is formed by polymerizing acrylic acid and / or a sulfonyl-containing vinyl monomer. According to the self-adaptive strong-anchoring phosphorus-free physical stripping descaling polymer and the preparation method thereof, the molecular structure of the polymer does not contain phosphorus, the eutrophication risk of phosphorus to a water body is completely eradicated from the source, the global environmental protection trend and strict regulation requirements are met, and the advantages of being free of phosphorus, environmentally friendly, green and safe are achieved.

Description

Technical Field

[0001] This invention relates to the field of industrial cleaning materials technology, specifically to a phosphorus-free polymeric descaling material with wide pH adaptability based on a novel physical mechanism, as well as its preparation method and application. Background Technology

[0002] Scale buildup on industrial equipment, especially hard scale such as calcium carbonate and calcium sulfate, severely restricts production efficiency and equipment safety. Current mainstream chemical cleaning technologies face a triple dilemma:

[0003] 1) Phosphorus content issue: Scale inhibitors / cleaning agents, such as ATMP, HEDP and phosphonic polymers (e.g., CN1178867C), contain phosphorus, which poses a risk of eutrophication of water bodies;

[0004] 2) pH limitation: The performance of traditional polycarboxylic acids (such as polyacrylic acid PAA) and green phosphorus-free agents (such as polyepoxysuccinic acid PESA) is highly dependent on pH. They are acceptable under neutral conditions, but they are prone to rapid failure under alkaline operating conditions with high pH (>9) due to charge repulsion or self-precipitation.

[0005] 3) Bottleneck of action mechanism: The above products are all based on "chemical action" (chelation, lattice distortion, dispersion), and their target is ions or microcrystals. For millimeter-sized dense hard scale that has already formed, it is like trying to "remove the sand dune" by "dissolving sand grains", which is inefficient and the cleaning cycle can take several days or even weeks.

[0006] Existing technologies attempt to improve the situation by combining alkali agents, strong chelating agents (such as EDTA), or surfactants, but they cannot fundamentally overcome the speed limits and pH dependence of chemical reactions. Especially with the trend towards phosphate-free treatments, finding environmentally friendly hard scale solutions that can operate efficiently in alkaline environments has become an urgent industry need. Summary of the Invention

[0007] To address the technical bottlenecks of existing phosphate-free cleaning agents failing under alkaline conditions and slow removal of hard scale, as well as the environmental restrictions faced by phosphate-containing cleaning agents, this invention provides a novel material that is completely independent of phosphorus chemistry and can rapidly remove hard scale through physical action over a wide pH range (especially under alkaline conditions).

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] An adaptive, strongly anchored, phosphorus-free physical stripping descaling polymer, which is a copolymer having an ABC-type triblock structure as shown in formula (I):

[0010] -[A]m-[B]n-[C]p-(I)

[0011] in,

[0012] Block A is a phosphorus-free rigid anchoring block, which is polymerized from monomers selected from formula (II) or formula (III) with a degree of polymerization m of 5-50;

[0013] Formula (II): CH2=CR¹-COO-(CH2)q-Ar-(COOH)r,

[0014] Where R¹ is H or CH3, q is an integer from 0 to 3, Ar is a benzene ring, naphthalene ring or anthracene ring, and r is an integer from 2 to 4;

[0015] Formula (III): CH2=CR¹-CONH-(CH2)s-crown ether group,

[0016] Where R¹ is H or CH3, s is an integer from 1 to 4, and the crown ether group is a derivative of 12-crown-4, 15-crown-5, or 18-crown-6;

[0017] Block B is a pH-responsive smart block, which is polymerized from vinyl monomers containing tertiary amine groups with a degree of polymerization n of 10-100. This block is used to respond to changes in environmental pH and adjust the force conduction efficiency from block C to block A through conformational change.

[0018] Block C is a flexible traction block, which is polymerized from acrylic acid and / or vinyl monomers containing sulfonic acid groups, with a degree of polymerization p of 20-200, and the number average molecular weight of the block is ≤10,000.

[0019] The total molecular weight of the copolymers is 15,000-80,000, and they do not contain phosphorus.

[0020] Furthermore, the vinyl monomer containing a tertiary amine group is selected from any one of dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, or 4-vinylpyridine.

[0021] Furthermore, the monomer of block A is selected from any one of methyl 5-vinyl-1,3-naphthalenedicarboxylate or its hydrolysis product, vinylbenzo-15-crown-5, or vinylbenzo-18-crown-6.

[0022] Furthermore, the monomer of block C is selected from any one or more of acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, or hydroxyethyl acrylate.

[0023] Furthermore, the polymer exhibits higher physical exfoliation efficiency at high pH levels than at neutral pH levels, demonstrating pH-adaptive synergistic properties.

[0024] Furthermore, the number-average molecular weight of the polymer is 30,000-60,000.

[0025] The present invention also provides a method for preparing an adaptive, strongly anchored, phosphorus-free physical stripping and descaling polymer, which employs sequential reversible addition-fragmentation chain transfer polymerization to sequentially polymerize block A, block B, and block C.

[0026] Furthermore, the RAFT reagent is selected from either cyanoisopropyl dithiobenzoate or 4-cyano-4-(thiobenzoyl)valerate.

[0027] The present invention also provides an application of an adaptive strong anchoring phosphorus-free physical stripping descaling polymer, wherein the adaptive strong anchoring phosphorus-free physical stripping descaling polymer is used in the preparation of a phosphorus-free powerful descaling agent composition, and the adaptive strong anchoring phosphorus-free physical stripping descaling polymer is used as the core active ingredient, and its mass content is 0.01%-10%.

[0028] This invention also provides an application of an adaptive, strongly anchored, phosphorus-free, physically exfoliating descaling polymer. The application of this polymer in removing hard scale from the surface of industrial equipment involves using a treatment solution containing the polymer to perform online circulation treatment on the surface of the industrial equipment under fluid shearing action. Rapid descaling is achieved by utilizing the physical exfoliation effect and pH adaptive synergistic properties of the polymer.

[0029] Compared with existing technologies, this invention provides an adaptive, strongly anchored, phosphorus-free physical stripping descaling polymer and its preparation method, which has the following beneficial effects:

[0030] 1. The adaptive strong anchoring phosphorus-free physical stripping descaling polymer and its preparation method contain no phosphorus in the polymer molecular structure, thus eliminating the risk of eutrophication of water bodies by phosphorus from the source. It meets global environmental protection trends and strict regulatory requirements, and achieves the advantages of being phosphorus-free, environmentally friendly, green and safe.

[0031] 2. This adaptive, strongly anchored, phosphorus-free physical stripping descaling polymer and its preparation method overcome the limitation of traditional phosphorus-free cleaning agents being prone to failure at high pH. It can effectively remove scale in the pH range of 6-11, and exhibits a faster stripping rate under alkaline conditions of pH 9-11, achieving "pH adaptive enhancement".

[0032] 3. This adaptive, strongly anchored, phosphorus-free physical stripping descaling polymer and its preparation method abandon the traditional chemical dissolution mode. It directly destroys the bonding interface between the scale layer and the substrate through the "physical stripping" mechanism. The removal speed of millimeter-sized hard scale is an order of magnitude faster than that of traditional chemical cleaning agents, which greatly shortens the cleaning cycle. It achieves an innovative descaling mechanism and the advantage of fast descaling speed.

[0033] 4. The adaptive strong anchoring phosphorus-free physical stripping descaling polymer and its preparation method, through the ABC triblock structure, respectively undertake the functions of anchoring, response regulation and traction, with significant synergistic effect. In particular, under alkaline conditions, the conformational shrinkage of segment B enhances force transmission, realizing dynamic optimization of mechanical efficiency.

[0034] 5. The adaptive strong anchoring phosphorus-free physical stripping descaling polymer and its preparation method are suitable for online circulating cleaning in power plants, chemical industry, metallurgy and other industries. It does not require shutdown for acid adjustment, is easy to operate, has low cost, and has good prospects for industrialization and market application. Attached Figure Description

[0035] Figure 1 This is a process flow diagram of an adaptive, strongly anchored, phosphorus-free physical stripping descaling polymer and its preparation method according to the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Please see Figure 1 .

[0038] Example 1: Preparation of polymer P1 (A: Naphthalenedicarboxylic acid derivative; B: DMAEMA; C: AA / AMPS)

[0039] Step S1: Synthesize block A

[0040] S1-1: Under nitrogen protection, add 100 mg of 4-cyano-4-(thiobenzoyl)valerate (CPDB, RAFT reagent) and 10 mL of tetrahydrofuran (THF) to a dry reaction flask and stir to dissolve.

[0041] S1-2: Add 2.0 g of methyl 5-vinyl-1,3-naphthalenedicarboxylate (VNDM) monomer and 5 mg of AIBN (initiator), and react at 70 °C for 12 hours.

[0042] S1-3: After the reaction is complete, the reaction solution is added dropwise into a large amount of cold methanol to precipitate the product. After centrifugation and vacuum drying, a light yellow solid product is obtained, which is the macromolecular RAFT reagent P(A)-CTA.

[0043] S1-4: Its number-average molecular weight is approximately 3,500, and its degree of polymerization is approximately 15, as determined by GPC.

[0044] Step S2: Synthesize block B

[0045] S2-1: Using the above P(A)-CTA as a macromolecular RAFT reagent, add 50 mg AIBN and 15 mL DMAEMA monomer, and dissolve in 30 mL THF.

[0046] S2-2: The reaction was carried out at 70℃ for 18 hours. After the reaction was completed, the product was precipitated in cold diethyl ether, centrifuged and dried to obtain P(A)-bP(B) block copolymer.

[0047] S2-3: Its number-average molecular weight was determined to be approximately 18,000, and the degree of polymerization in segment B was approximately n≈60.

[0048] Step S3: Synthesize block C

[0049] S3-1: Using the above P(A)-bP(B) as a macromolecular RAFT reagent, add 30 mg AIBN, 8 g acrylic acid (AA) and 0.5 g 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and dissolve in 40 mL DMF.

[0050] S3-2: The reaction was carried out at 65°C for 20 hours. After the reaction was completed, the product was purified by dialysis (molecular weight cutoff 3,500) and freeze-dried to obtain the final product P1.

[0051] S3-3: Its total molecular weight was determined to be approximately 45,000, the degree of polymerization of the C segment was approximately 120, and the number-average molecular weight of the C segment was approximately 8,600.

[0052] Step S4: A-segment ester hydrolysis

[0053] S4-1: Dissolve P1 in NaOH aqueous solution (pH=12), stir and hydrolyze at 60℃ for 6 hours to completely hydrolyze methyl naphthalene into carboxylate form.

[0054] S4-2: Adjust the pH to 7 with HCl, dialyze again, and freeze dry to obtain the final soluble polymer P1.

[0055] Example 2: Preparation of polymer P2 (A: vinylbenzo-15-crown-5; B: DMAEMA; C: AA)

[0056] The steps are similar to those in Example 1, except that:

[0057] The monomer in segment A was replaced with 2.5 g of vinylbenzo-15-crown-5 (synthesized according to the literature method).

[0058] Section C uses only acrylic monomers and does not use AMPS.

[0059] The final product P2 has a total molecular weight of approximately 38,000, with a degree of polymerization of m≈8 in segment A, n≈50 in segment B, and p≈100 in segment C.

[0060] Scale settings:

[0061] To verify the effectiveness of the present invention, the following comparative examples were set up:

[0062] D1: Commercially available polyepoxysuccinic acid (PESA, Mn≈4,000).

[0063] D2: Phosphoric acid-modified polyacrylic acid compound (prepared according to CN1178867C).

[0064] D3: Sodium polyacrylate (PAAS, Mn≈8,000);

[0065] D4: Physically mix the block homopolymers from Example 1 at a mass ratio of A:B:C of 1:3:5.

[0066] Performance testing of the above embodiments:

[0067] 1. Descaling rate test:

[0068] Prepare a 1.0 mm thick standard calcium carbonate scale sheet and place it in a dynamic circulation device.

[0069] Prepare a test solution containing 200 ppm of active ingredient and wash at pH=7 and pH=10 at 50℃ and a flow rate of 1.5 m / s.

[0070] The time required to remove 90% of the scale was recorded, and the results are shown in Table 1.

[0071] Table 1 Comparison of Descaling Efficiency

[0072] sample pH=7 Removal time (h) pH=10 Removal time (h) Performance Evaluation P1 14 9 High pH efficiency increased by 36% P2 16 12 High pH efficiency improvement D1 >72 >72 (Almost ineffective) Completely ineffective at high pH D2 48 60 (Solution instability) Performance decreases at high pH D3 >72 >72 Invalid D4 24 22 Without pH enhancement, the effect is poor.

[0073] Conclusion: The products of this invention (P1, P2) exhibit a unique efficiency improvement (adaptive synergy) under alkaline conditions, while all comparative examples either fail, or their performance decreases or remains unchanged at pH=10, demonstrating a significant advantage.

[0074] 2. QCM-D simulated peeling experiment:

[0075] A polymer solution is passed through a chip coated with CaCO3, and after adsorption to form a film, a high-shear flow is applied.

[0076] Monitoring the rate of frequency recovery (ΔF), P1 showed a significantly faster ΔF recovery rate at pH=10 than at pH=7, and was much higher than all comparative examples, demonstrating that its exfoliation kinetics are faster at high pH.

[0077] 3. AFM force spectrum analysis:

[0078] The single-molecule release force curve of P1 molecule on CaCO3 surface was measured, showing multiple bonding characteristics and confirming the strong physical anchoring effect of segment A.

[0079] Industrial application examples:

[0080] A combined heat and power (CHP) unit's condenser had circulating water with a pH maintained between 9.5 and 10.2, exhibiting severe calcium carbonate scale buildup. A 200 ppm cleaning solution (P1) was prepared and circulated at a normal flow rate while maintaining a system pH of 10.0. After 12 hours, the terminal temperature difference returned to the design value. A shutdown inspection revealed extensive flaking of the scale, leaving the metal substrate intact. The entire cleaning process required no acid adjustment and produced no phosphorus emissions, representing an efficiency improvement of over 400% compared to traditional chemical cleaning methods (estimated to take 5-7 days and requiring acid adjustment).

[0081] in conclusion:

[0082] The adaptive, strongly anchored, phosphorus-free, physically exfoliating descaling polymer provided by this invention achieves two major paradigm shifts in cleaning technology through the innovative synergistic design of the A, B, and C triblocks: from "chemical dissolution" to "physical exfoliation," and from "pH tolerance" to "pH-adaptive enhancement." Its superior performance under alkaline conditions solves a long-standing pain point in the field of phosphorus-free cleaning, possessing significant environmental value and economic benefits, and demonstrating high prospects for industrialization and patent licensing.

[0083] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An adaptive, strongly anchoring, phosphorus-free physical stripping and descaling polymer, characterized in that, It is a copolymer with an ABC-type triblock structure as shown in formula (I): -[A]m-[B]n-[C]p-(I) in, Block A is a phosphorus-free rigid anchoring block, which is polymerized from monomers selected from formula (II) or formula (III) with a degree of polymerization m of 5-50; Formula (II): CH2=CR¹-COO-(CH2)q-Ar-(COOH)r, Where R¹ is H or CH3, q is an integer from 0 to 3, Ar is a benzene ring, naphthalene ring or anthracene ring, and r is an integer from 2 to 4; Formula (III): CH2=CR¹-CONH-(CH2)s-crown ether group, Where R¹ is H or CH3, s is an integer from 1 to 4, and the crown ether group is a derivative of 12-crown-4, 15-crown-5, or 18-crown-6; Block B is a pH-responsive smart block, which is polymerized from vinyl monomers containing tertiary amine groups with a degree of polymerization n of 10-100. This block is used to respond to changes in environmental pH and adjust the force conduction efficiency from block C to block A through conformational change. Block C is a flexible traction block, which is polymerized from acrylic acid and / or vinyl monomers containing sulfonic acid groups, with a degree of polymerization p of 20-200, and the number average molecular weight of the block is ≤10,000. The total molecular weight of the copolymers is 15,000-80,000, and they do not contain phosphorus.

2. The adaptive, strongly anchoring, phosphorus-free physical stripping and descaling polymer according to claim 1, characterized in that, The vinyl monomer containing a tertiary amine group is selected from any one of dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, or 4-vinylpyridine.

3. The adaptive, strongly anchored, phosphorus-free physical stripping and descaling polymer according to claim 1, characterized in that, The monomer of block A is selected from any one of methyl 5-vinyl-1,3-naphthalenedicarboxylate or its hydrolysis product, vinylbenzo-15-crown-5 or vinylbenzo-18-crown-6.

4. The adaptive, strongly anchored, phosphorus-free physical stripping and descaling polymer according to claim 1, characterized in that, The monomer of block C is selected from any one or more of acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, or hydroxyethyl acrylate.

5. The adaptive, strongly anchoring, phosphorus-free physical stripping and descaling polymer according to claim 1, characterized in that, The polymer exhibits higher physical exfoliation efficiency at high pH than at neutral pH, demonstrating pH-adaptive synergistic properties.

6. The adaptive, strongly anchored, phosphorus-free physical stripping and descaling polymer according to claim 1, characterized in that, The number average molecular weight of the polymer is 30,000-60,000.

7. A method for preparing the adaptive, strongly anchored, phosphorus-free physical stripping and descaling polymer as described in any one of claims 1-6, characterized in that, Sequential reversible addition-fracture chain transfer polymerization was used to polymerize blocks A, B, and C in sequence.

8. The preparation method of the adaptive strong anchoring phosphorus-free physical stripping descaling polymer according to claim 7, characterized in that, The RAFT reagent is selected from either cyanoisopropyl dithiobenzoate or 4-cyano-4-(thiobenzoyl)valerate.

9. The application of an adaptive, strongly anchoring, phosphorus-free, physically stripping descaling polymer, as described in any one of claims 1-6, in the preparation of a phosphorus-free, powerful descaling agent composition, characterized in that... The active ingredient comprises the adaptive strong anchoring phosphorus-free physical stripping descaling polymer as described in any one of claims 1-6, with a mass content of 0.01%-10%.

10. An application of an adaptive, strongly anchoring, phosphorus-free, physically exfoliating descaling polymer, as described in any one of claims 1-6, in removing hard scale from the surface of industrial equipment, characterized in that... The surface of industrial equipment is treated online using a treatment fluid containing the aforementioned descaling polymer under fluid shearing action. Rapid descaling is achieved by utilizing the physical stripping effect and pH adaptive synergistic properties of the descaling polymer.

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