Surface modification method of aluminum diethylphosphinate
By performing surface crosslinking modification of ADP and three-dimensional modification of sol-gel technology, polyhydroxy and three-dimensional spatial network structures are formed, which solves the problems of poor dispersion and insufficient compatibility of ADP in aqueous materials, and has achieved significant improvement in its hydrophilic properties and improved thermal stability properties.
Patent Information
- Application Number
- CN202411946565.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-03-14
AI Technical Summary
The hydrophobicity of ADP is too strong, which makes it difficult to disperse in aqueous materials, poor compatibility, and easy to break the milk.
By using PVA to modify ADP surface crosslinking to generate a polyhydroxy structure, then using sol-gel technology on the ADP surface to form a three-dimensional spatial network structure to improve the hydrophilic performance of ADP.
It significantly improves the hydrophilic properties of ADP, improves its dispersion and compatibility in aqueous materials, avoids demulsification, and improves thermal stability performance.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to a surface grafting technology and a sol-gel technology. PVA is used to carry out surface grafting on aluminum diethylphosphinate (ADP) to obtain g-ADP. Then, the sol-gel technology is used to carry out surface modification on the g-ADP, and a layer of three-dimensional space network structure is attached to the surface of the g-ADP to prepare Modified-ADP. Background Art
[0002] Aluminum diethylphosphinate (ADP) is a green and environmentally friendly organic phosphorus flame retardant. Its chemical structure is as follows:
[0003]
[0004] Due to its special structure, ADP can play a flame retardant role in both the gas phase and the condensed phase. The metal cations in ADP can prevent the volatilization of flame retardants and suppress smoke, which together give the polymer matrix flame retardant properties. ADP has attracted widespread attention due to its high flame retardant efficiency, low smoke and non-toxicity, good thermal stability, and high phosphorus content. It can be widely used in thermoplastic materials such as PA6, PA66, PBT, and in the flame retardant modification of fiber fabrics, and has good prospects. However, it also has some shortcomings, such as poor hydrophilicity of ADP, poor compatibility with water-based substrates, uneven dispersion, and easy demulsification. In order to solve the problems of ADP, ADP needs to be surface modified.
[0005] PVA is a linear polyhydroxy organic polymer that is non-toxic, tasteless and non-irritating. Due to its good biocompatibility and low cost, it is an ideal green and environmentally friendly material. PVA has strong polarity and is easy to form intramolecular and intermolecular hydrogen bonds, so it has a high degree of crystallinity. In addition, the polyhydroxy structure in PVA can undergo esterification, etherification and acetalization reactions. The chemical properties of hydroxyl groups are very active and are easy to react with other active groups to form stable covalent bonds and cross-linked network structures. Finally, PVA also has strong adhesion and is a good adhesive.
[0006] Sol-gel technology is a process of hydrolysis and polycondensation of metal alkoxides to form a uniform, stable and transparent sol system, which is then gelled to ultimately obtain a network structure of oxides or other compounds. Summary of the invention
[0007] In order to solve the problems that ADP is too hydrophobic, difficult to disperse in aqueous materials, poor compatibility, and easy to demulsify, the present invention uses PVA to crosslink and modify ADP, generates polyhydroxy substances on the surface of ADP, and then uses sol-gel technology on the surface of g-ADP, uses TEOS or other silicon sources as precursors, and undergoes hydrolysis and polycondensation under certain conditions to jointly generate a silicon-oxygen-silicon and silicon-oxygen-carbon spatial network structure on the surface of g-ADP and the hydroxyl groups in PVA to prepare Modified-ADP, thereby achieving the purpose of improving the hydrophilicity of ADP.
[0008] In one aspect, the present invention provides a method for surface modification of aluminum diethylphosphinate, the method comprising the following steps:
[0009] Step 1: Surface cross-linking modification,
[0010] In this step, PVA is used to crosslink and modify ADP, so that a multi-hydroxy structure is grafted onto the surface of ADP. The specific steps are as follows:
[0011] Add ADP powder to the PVA aqueous solution, react at 60-100°C for 2-8h, filter, wash, dry, and crush to obtain cross-linked modified g-ADP;
[0012] Preferably, the PVA is type 1799;
[0013] Preferably, the PVA aqueous solution is a 6-12% PVA aqueous solution, most preferably an 8% PVA aqueous solution;
[0014] Preferably, the reaction temperature is 90°C and the reaction time is 4h;
[0015] Step 2: 3D surface modification,
[0016] In this step, the g-ADP obtained in step 1 is subjected to secondary surface modification using sol-gel technology to form a three-dimensional network structure on the surface of ADP. The specific steps are as follows:
[0017] Step 2-1: using silicate as a precursor and anhydrous ethanol as a co-solvent, preparing a silica sol solution in an aqueous phase, dispersing g-ADP in the silica sol solution to obtain a g-ADP dispersed solution; the molar ratio of silicate: anhydrous ethanol: water is 1:1-20:1-20;
[0018] Preferably, the silicate is TEOS;
[0019] Preferably, the molar ratio of silicate: anhydrous ethanol: water is 1:2:4;
[0020] Preferably, the step of preparing the silica sol solution and dispersing g-ADP in the silica sol solution is to first weigh anhydrous ethanol and water, mix them evenly, add a certain mass of g-ADP, stir to make it evenly dispersed, and then slowly drop silicate to obtain a g-ADP dispersion solution;
[0021] Step 2-2, adjusting the pH of the dispersed solution to 2-5 to fully hydrolyze the silicate;
[0022] Preferably, the pH adjusting agent is a 0.1M-1M HCl solution, most preferably a 0.1M HCl solution;
[0023] Preferably, the hydrolysis temperature is 25-90°C, and the hydrolysis time is 2-24h; most preferably, the hydrolysis temperature is 60°C, and the hydrolysis time is 4h.
[0024] Step 2-3, after the hydrolysis is completed, the pH of the reaction solution is adjusted to 9-11 to carry out polycondensation reaction;
[0025] Preferably, the pH adjusting agent is aqueous ammonia;
[0026] Preferably, the polymerization temperature is 60°C-100°C, and the polymerization time is 2-8h. Most preferably, the polymerization temperature is 80°C, and the polymerization time is 6h.
[0027] Step 2-4, after the polycondensation reaction is completed, the reaction solution is filtered, washed, and dried to obtain modified ADP.
[0028] On the other hand, the present invention provides a modified aluminum diethylphosphinate, which is prepared by the above method. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 Schematic diagram of the two-dimensional structure of the modified ADP of the present invention.
[0030] Figure 2 Schematic diagram of the three-dimensional structure of the modified ADP of the present invention.
[0031] Figure 3 This is a comparison of electron microscope images of pure ADP and modified ADP.
[0032] Figure 4 This is the dispersion effect diagram of pure ADP and modified ADP waterborne polyurethane.
[0033] Figure 5 These are the TGA test graphs of pure ADP and modified ADP. DETAILED DESCRIPTION
[0034] The following is an explanation of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.
[0035] Example 1
[0036] Select 1799 PVA, weigh 6g of PVA, dissolve it in 94g of deionized water, prepare a 6% PVA aqueous solution, the dissolution temperature is 95℃, add 100g of ADP powder, react for 4h, filter, wash, dry and crush while hot to obtain modified g-ADP. Then use sol-gel technology, use TEOS as precursor and anhydrous ethanol as co-solvent to prepare a silica sol solution in g-ADP-water phase. Among them, according to the molar ratio of TEOS: anhydrous ethanol: water of 1:2:4, 18.43g of anhydrous ethanol and 14.4g of water were weighed, 78.06g of g-ADP was added, stirred and dispersed evenly, 41.67g of TEOS was slowly added dropwise at 60°C, and after the addition was completed, 0.1M HCl solution was used to adjust the pH of the reaction solution to 2-3, the reaction temperature was 60°C, and the reaction time was 4h, so that TEOS was fully hydrolyzed; then ammonia water was slowly added to the system to make the pH of the reaction solution = 9-10, the temperature was increased to 80°C, and the reaction was carried out for 6h, so that TEOS was fully polymerized on the surface of g-ADP. Finally, the modified ADP was obtained by filtering, washing and drying while hot.
[0037] Example 2
[0038] Select 1799 PVA, weigh 8g of PVA, dissolve it in 92g of deionized water, prepare 8% PVA aqueous solution, dissolve at 95℃, add 100g of ADP powder, react for 4h, filter, wash, dry and crush while hot to obtain modified g-ADP. Then use sol-gel technology, use TEOS as precursor and anhydrous ethanol as co-solvent to prepare a silica sol solution in g-ADP-water phase. Among them, according to the molar ratio of TEOS: anhydrous ethanol: water of 1:2:4, 18.43g of anhydrous ethanol and 14.4g of water were weighed, 78.06g of g-ADP was added, stirred and dispersed evenly, 41.67g of TEOS was slowly added dropwise at 60°C, and after the addition was completed, 0.1M HCl solution was used to adjust the pH of the reaction solution to 2-3, the reaction temperature was 60°C, and the reaction time was 4h, so that TEOS was fully hydrolyzed; then ammonia water was slowly added to the system to make the pH of the reaction solution = 9-10, the temperature was increased to 80°C, and the reaction was carried out for 6h, so that TEOS was fully polymerized on the surface of g-ADP. Finally, the modified ADP was obtained by filtering, washing and drying while hot.
[0039] Example 3
[0040] Select 1799 PVA, weigh 10g of PVA, dissolve it in 90g of deionized water, prepare a 10% PVA aqueous solution, the dissolution temperature is 95℃, add 100g of ADP powder, react for 4h, filter, wash, dry and crush while hot to obtain modified g-ADP. Then use sol-gel technology, use TEOS as precursor and anhydrous ethanol as co-solvent to prepare a silica sol solution in g-ADP-water phase. Among them, according to the molar ratio of TEOS: anhydrous ethanol: water of 1:2:4, 18.43g of anhydrous ethanol and 14.4g of water were weighed, 78.06g of g-ADP was added, stirred and dispersed evenly, 41.67g of TEOS was slowly added dropwise at 60°C, and after the addition was completed, 0.1M HCl solution was used to adjust the pH of the reaction solution to 2-3, the reaction temperature was 60°C, and the reaction time was 4h, so that TEOS was fully hydrolyzed; then ammonia water was slowly added to the system to make the pH of the reaction solution = 9-10, the temperature was increased to 80°C, and the reaction was carried out for 6h, so that TEOS was fully polymerized on the surface of g-ADP. Finally, the modified ADP was obtained by filtering, washing and drying while hot.
[0041] Example 4
[0042] Select 1799 PVA, weigh 12g of PVA, dissolve it in 88g of deionized water, prepare a 12% PVA aqueous solution, the dissolution temperature is 95℃, add 100g of ADP powder, react for 4h, filter, wash, dry and crush while hot to obtain modified g-ADP. Then use sol-gel technology, use TEOS as precursor and anhydrous ethanol as co-solvent to prepare a silica sol solution in g-ADP-water phase. Among them, according to the molar ratio of TEOS: anhydrous ethanol: water of 1:2:4, 18.43g of anhydrous ethanol and 14.4g of water were weighed, 78.06g of g-ADP was added, stirred and dispersed evenly, 41.67g of TEOS was slowly added dropwise at 60°C, and after the addition was completed, 0.1M HCl solution was used to adjust the pH of the reaction solution to 2-3, the reaction temperature was 60°C, and the reaction time was 4h, so that TEOS was fully hydrolyzed; then ammonia water was slowly added to the system to make the pH of the reaction solution = 9-10, the temperature was increased to 80°C, and the reaction was carried out for 6h, so that TEOS was fully polymerized on the surface of g-ADP. Finally, the modified ADP was obtained by filtering, washing and drying while hot.
[0043] Example 5
[0044] The performance test of the modified ADP obtained in Example 3 was further compared with that of pure ADP:
[0045] Since the highly hydrophilic polyvinyl alcohol (PVA) was used as a crosslinker to carry out surface grafting modification on ADP, and then the g-ADP was modified by sol-gel technology, a spatial network structure of silicon-oxygen-silicon and silicon-oxygen-carbon was generated on the surface of ADP, which greatly improved the hydrophilicity of ADP. The schematic diagram of the two-dimensional structure of modified ADP can be found in Figure 1 , see the three-dimensional structure diagram Figure 2 The morphology of ADP before and after modification was observed by electron microscopy. Figure 3 As shown, Figure a and Figure b are pure ADP, and Figure c and Figure d are modified ADP of Example 3. According to the comparison between Figure a and Figure c, it is found that the pure ADP powder has a fine particle size and a uniform and delicate surface (as shown in Figure a); the modified ADP has a rough surface and the particle size is significantly coarsened (as shown in Figure c), indicating that the ADP is successfully modified by the method disclosed in the present invention to obtain a modified ADP product. Figure b is an enlarged view of pure ADP, and it can be seen that ADP is cross-linked, which may be because the ADP particle size is too fine and agglomerated together; Figure d is an enlarged view of the modified ADP, and it can be seen that the modified ADP particles are distinct, and the local accumulation of products leads to larger particles. According to the comparison diagram before and after the modification of ADP, it can be concluded that the ADP is successfully modified by the method disclosed in the present invention.
[0046] A comparison experiment of the surface complete wetting time of ADP before and after modification was conducted. The modified ADP obtained in Example 3 can be completely wetted after stirring for 30 seconds, while pure ADP cannot be wetted even after prolonged stirring. It can be seen that the wetting time of the modified ADP is greatly shortened compared with that of pure ADP.
[0047] In order to further verify the hydrophilicity of ADP before and after modification and its compatibility in aqueous substrates, a 10 wt% ADP aqueous polyurethane solution was prepared to compare the dispersion of ADP in aqueous polyurethane before and after modification. The comparison diagram is as follows: Figure 4 As shown, it can be found that pure ADP has poor compatibility with water-based polyurethane and has strong hydrophobic properties, while the modified ADP obtained in Example 3 can be quickly dispersed in water-based polyurethane, has good compatibility with water-based polyurethane, has greatly improved hydrophilic properties, and does not demulsify in water-based polyurethane emulsion.
[0048] Finally, the modified ADP product obtained in Example 3 and pure ADP were subjected to TGA test. According to the test results, the modified ADP has better thermal stability. The TGA results are as follows: Figure 5 shown.
Claims
1. A surface modification method of aluminum diethylphosphinate, comprising the following steps: Step 1: Surface cross-linking modification, Add ADP powder to the PVA aqueous solution, react at 60-100°C for 2-8h, filter, wash, dry, and crush to obtain cross-linked modified g-ADP; Step 2: 3D surface modification, Step 2-1: using silicate as a precursor and anhydrous ethanol as a co-solvent, preparing a silica sol solution in an aqueous phase, dispersing g-ADP in the silica sol solution to obtain a g-ADP dispersed solution; the molar ratio of silicate: anhydrous ethanol: water is 1:1-20:1-20; Step 2-2, adjusting the pH of the dispersed solution to 2-5 to fully hydrolyze the silicate; Step 2-3, after the hydrolysis is completed, the pH of the reaction solution is adjusted to 9-11 to carry out polycondensation reaction; Step 2-4, after the polycondensation reaction is completed, the reaction solution is filtered, washed, and dried to obtain modified ADP.
2. The method according to claim 1, characterized in that The PVA is type 1799.
3. The method according to claim 1, characterized in that The PVA aqueous solution is a 6-12% PVA aqueous solution, preferably an 8% PVA aqueous solution.
4. The method according to claim 1, characterized in that The silicate is TEOS.
5. The method according to claim 1, characterized in that The molar ratio of silicate: anhydrous ethanol: water is 1:2:
4.
6. The method according to claim 1, characterized in that The steps of preparing the silica sol solution and dispersing g-ADP in the silica sol solution are: first weighing anhydrous ethanol and water, mixing them evenly, adding a certain mass of g-ADP, stirring to make it evenly dispersed, and then slowly dropping silicate to obtain a g-ADP dispersed solution.
7. The method according to claim 1, characterized in that The pH adjusting reagent in step 2-2 is 0.1M-1M HCl solution; the pH adjusting reagent in step 2-4 is ammonia water.
8. The method according to claim 1, characterized in that The hydrolysis temperature is 25-90° C., and the hydrolysis time is 2-24 hours.
9. The method according to claim 1, characterized in that The polymerization temperature is 60° C.-100° C., and the polymerization time is 2-8 hours.
10. A modified aluminum diethylphosphinate, wherein the modified aluminum diethylphosphinate is prepared by the method according to any one of claims 1 to 9.