阅读说明：本技术 一种基于石墨化氮化碳复合插层改性的磷酸锆阻燃剂及其制备方法 (Zirconium phosphate flame retardant modified based on graphitized carbon nitride composite intercalation and preparation method thereof ) 是由 刘治田 王成 刘诗 张旗 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种基于石墨化氮化碳复合插层改性的磷酸锆阻燃剂,首先利用客体小分子胺对磷酸锆进行预撑改性,增大磷酸锆层间距离,然后在预插层的磷酸锆悬浮液中加入表面活性剂进行有机改性,最后将石墨化氮化碳引入有机改性的磷酸锆悬形成。本发明利用表面活性剂降低磷酸锆表面极性,增加树脂相容性,同时在磷酸锆中首次引入石墨化氮化碳,形成插层-剥离结构,借由石墨化氮化碳的类石墨空间网状结构提高所得阻燃剂的热稳定性,同时季铵盐表面活性剂,氮化碳复合插层物质形成碳-氮-磷-锆协效阻燃作用,所得阻燃剂集阻燃抑烟与增强功能于一体,无卤、成炭性好,阻燃性能优异,环境友好,且涉及的制备方法工艺简单,适合推广应用。(The invention discloses a zirconium phosphate flame retardant modified by composite intercalation based on graphitized carbon nitride. The invention utilizes the surfactant to reduce the surface polarity of zirconium phosphate, increases the compatibility of resin, simultaneously introduces graphitized carbon nitride into zirconium phosphate for the first time to form an intercalation-exfoliation structure, improves the thermal stability of the obtained flame retardant by virtue of the graphite-like spatial network structure of the graphitized carbon nitride, simultaneously utilizes the quaternary ammonium salt surfactant and the carbon nitride composite intercalation substance to form a carbon-nitrogen-phosphorus-zirconium synergistic flame retardant effect, integrates the flame retardant and smoke suppression functions into a whole, has no halogen, good char formation, excellent flame retardant property and environmental friendliness, and the related preparation method has simple process and is suitable for popularization and application.)

1. A preparation method of a graphitized carbon nitride composite intercalation modified zirconium phosphate flame retardant is characterized by comprising the following steps:

1) dispersing zirconium phosphate in water to prepare a zirconium phosphate suspension, adding a small molecular amine solution into the zirconium phosphate suspension, uniformly stirring, and then carrying out ultrasonic treatment to obtain a pre-intercalated zirconium phosphate suspension;

2) dropwise adding a surfactant solution into the pre-intercalated zirconium phosphate suspension obtained in the step 1), and carrying out heating ultrasonic treatment under the stirring condition to obtain a surfactant intercalated modified zirconium phosphate suspension;

3) ultrasonically dispersing graphitized carbon nitride in water, preparing a carbon nitride suspension, dropwise adding the carbon nitride suspension into the suspension obtained in the step 2), mechanically stirring, standing, centrifuging, washing and drying to obtain the graphitized carbon nitride composite intercalation modified zirconium phosphate flame retardant.

2. The preparation method according to claim 1, wherein the surfactant is one or more of cetyltrimethylammonium bromide, Gemini surfactant, octadecyldimethylhydroxyethylamine, cetyltrimethylammonium sulfonate and octadecyltrimethylammonium sulfonate.

3. The preparation method of claim 1, wherein the small molecule amine is one or more of methylamine, ethylamine and ethylenediamine.

4. The preparation method according to claim 1, wherein the heating and ultrasonic treatment temperature in the step 2) is 30-100 ℃ and the time is 6-24 h.

5. The preparation method according to claim 1, wherein the molar ratio of the zirconium phosphate to the small molecule amine is 100:1 to 1: 50; the molar ratio of the zirconium phosphate to the surfactant is 1: 3-3: 2; the molar ratio of the zirconium phosphate to the carbon nitride is 2: 1-1: 20.

6. The method of claim 1, wherein the sonication time in step 1) is 6-12 hours.

7. The method of claim 1, wherein the mechanical stirring time in step 3) is 12 to 24 hours.

8. The zirconium phosphate flame retardant modified by the composite intercalation based on graphitized carbon nitride prepared by the preparation method of any one of claims 1 to 7.

Technical Field

The invention belongs to the technical field of novel flame-retardant smoke-suppressing additives, relates to a novel organic and inorganic hybrid flame-retardant smoke-suppressing additive, and particularly relates to a zirconium phosphate flame retardant modified based on graphitized carbon nitride composite intercalation and a preparation method thereof.

Background

In recent years, polymer layered nanocomposites have become one of the most widely studied materials in the nanocomposite field, mainly comprising: layered silicate, layered metal double hydroxide, layered phosphate layered metal salt compound, montmorillonite hydrotalcite and the like, and the polymer layered nano composite material has some special advantages: such as high strength, high heat resistance, high barrier property, good electric and heat conduction functions and the like, and further provides a good method for improving the thermal stability, fire resistance, flame retardance and mechanical properties of the polymer material.

Zirconium phosphate is a novel layered multifunctional material with a regular structure, the ion exchange capacity of the zirconium phosphate is 6 times of that of clay, the zirconium phosphate has the characteristics of controllable length-diameter ratio, narrow particle size distribution and the like, and is one of excellent matrixes for preparing polymer layered nano composite materials. The layered zirconium phosphate not only has the commonality of layered compounds, but also has the characteristics which other layered compounds do not have, such as larger ion exchange space, easy intercalation and stripping, adjustable interlayer spacing, solid acid characteristic and the like; meanwhile, because the zirconium phosphate layer is rich in Lewis acid points, the zirconium phosphate has good catalytic carbonization effect on various polymers, so that the zirconium phosphate has unique advantages in the field of polymer flame retardance. Although the flame retardance of the flame retardant can be obviously improved through the laminar barrier effect and the solid acid catalytic carbonization effect of ZrP, an expanded carbon layer formed by a common flame retardant system is loose and has poor thermal stability, the catalytic carbonization effect is short, the zirconium phosphate can not efficiently catalyze the polymer to form carbon, and the flame retardant efficiency of the flame retardant can not be qualitatively improved.

In order to solve the problems that the flame retardant efficiency is limited because zirconium phosphate can not efficiently catalyze the polymer to form carbon; patent No. cn201310550306.x, zinc borate is used to modify MCA, so that zinc borate is grafted on the particle surface of the generated MCA, thereby realizing effective dispersion of reactants in a reaction medium and reducing the viscosity of the reaction system, but zinc borate belongs to an inorganic flame retardant, and has poor compatibility with a resin matrix, resulting in poor flame retardant property and reduced processability; in patent CN108203519A, methylamine is intercalated into zirconium phosphate, the zirconium phosphate is peeled into a laminated layer after mechanical ball milling, nano-lamellar zirconium phosphate is added in the MCA synthesis process, and the zirconium phosphate is used as a synergist modified flame retardant and applied to a PA6 flame-retardant composite material, but the zirconium phosphate is only used as a synergist in the patent and only aims at a PA6 material, and the problems of large compounding amount, low flame-retardant efficiency and the like exist.

Therefore, the further optimization of the modification means and the performance of the zirconium phosphate compound has important research and application significance.

Disclosure of Invention

The invention mainly aims to solve the problems of poor char quality, low loose strength of a char layer, low flame retardant efficiency and the like of the existing flame retardant, and provides a graphitized carbon nitride composite intercalation modified zirconium phosphate flame retardant, which utilizes a composite intercalation substance to form a carbon-nitrogen-phosphorus-zirconium synergistic flame retardant effect, integrates flame retardant and smoke suppression functions into a whole, is halogen-free, has good char formation, excellent flame retardant performance, is environment-friendly, and is simple in related preparation method, and suitable for popularization and application.

In order to achieve the purpose, the invention adopts the technical scheme that:

a preparation method of a zirconium phosphate flame retardant modified based on graphitized carbon nitride composite intercalation comprises the following steps:

1) dispersing zirconium phosphate in water to prepare a zirconium phosphate suspension, adding a small molecular amine solution into the zirconium phosphate suspension, uniformly stirring, and then carrying out ultrasonic treatment to obtain a pre-intercalated zirconium phosphate suspension;

2) dropwise adding a surfactant solution into the pre-intercalated zirconium phosphate suspension obtained in the step 1), and carrying out heating ultrasonic treatment under the stirring condition to obtain a surfactant intercalated modified zirconium phosphate suspension;

3) ultrasonically dispersing graphitized carbon nitride in water, preparing a carbon nitride suspension, dropwise adding the carbon nitride suspension into the suspension obtained in the step 2), mechanically stirring, standing, centrifuging, washing and drying to obtain the graphitized carbon nitride composite intercalation modified zirconium phosphate flame retardant.

In the above scheme, the zirconium phosphate is alpha-zirconium phosphate.

In the scheme, the surfactant is one or more of cetyl trimethyl ammonium bromide, Gemini surfactant, octadecyl dimethyl hydroxyethyl amine, cetyl trimethyl ammonium sulfonate and octadecyl trimethyl ammonium sulfonate.

In the scheme, the small molecular amine is one or more of methylamine, ethylamine and ethylenediamine.

In the scheme, the ultrasonic treatment temperature in the step 1) is 20-80 ℃.

In the scheme, the heating ultrasonic treatment temperature in the step 2) is 30-100 ℃.

In the scheme, the molar ratio of the zirconium phosphate to the micromolecular amine is 100: 1-1: 50; preferably, the molar ratio of the zirconium phosphate to the small molecule amine is 10: 1-1: 10.

In the scheme, the molar ratio of the zirconium phosphate to the surfactant is 1: 3-3: 2.

In the scheme, the molar ratio of the zirconium phosphate to the carbon nitride is 2: 1-1: 20.

In the scheme, the washing step in the step 3) is to wash for 2-3 times by adopting acetone, wash for 2-3 times by adopting ethanol and wash for 2-3 times by adopting water.

In the scheme, the ultrasonic treatment time in the step 1) is 6-12 h.

In the scheme, the heating ultrasonic treatment time in the step 2) is 6-24 h.

In the scheme, the mechanical stirring time in the step 3) is 12-24 h.

In the scheme, the drying temperature is 60-80 ℃, and the drying time is 12-24 h.

In the scheme, the washing step in the step 3) is to wash for 2-3 times by adopting acetone, wash for 2-3 times by adopting ethanol and wash for 2-3 times by adopting water.

The zirconium phosphate flame retardant modified by the composite intercalation based on the graphitized carbon nitride is prepared according to the scheme.

The principle of the invention is as follows:

the alpha-zirconium phosphate is a multifunctional layered compound, has a stable layered structure, is easy to intercalate and strip, and has adjustable interlayer spacing; according to the invention, a plurality of small molecular amines are utilized to carry out pre-support treatment on alpha-zirconium phosphate, the distance between zirconium phosphate layers is increased, then, a surfactant is utilized to carry out organic modification, the surface activity of the zirconium phosphate sheet layer is reduced, the compatibility of a flame retardant and matrix resin is improved, and meanwhile, a phosphorus-nitrogen composite intercalation structure is formed, so that the flame retardant efficiency of the system can be obviously improved:

1) carbon nitride is introduced into the zirconium phosphate flame retardant, and can form a network structure layer in a condensed phase to protect an internal polymer from being influenced by external heat radiation and heat feedback from flame in the material combustion process, and the carbon nitride and the zirconium phosphate can show synergistic flame retardant property when used in cooperation; meanwhile, the carbon nitride only contains two elements of C and N and has a graphite-like spatial network structure, so that the carbon formation amount and the graphitization degree of a system can be improved by introducing the carbon nitride into the zirconium phosphate, and a formed carbon layer is more stable and compact; meanwhile, the surfactant is inserted into zirconium phosphate to form an intercalation-exfoliation structure, so that the surfactant and carbon nitride composite intercalation substance form a carbon-nitrogen-phosphorus-zirconium synergistic flame-retardant effect, and the flame-retardant efficiency of the flame retardant can be remarkably improved;

2) the carbon nitride is introduced by the surfactant to carry out intercalation modification on the zirconium phosphate, and the amine group carried by the carbon nitride can be inserted into the zirconium phosphate layer, so that the modification of the alpha-zirconium phosphate is more stable, the problems of molecular migration, precipitation cracking and the like are effectively solved, and the stability of the macromolecular flame retardant is improved.

3) The nitrogen element in the carbon nitride is used as a Lewis-basic site, so that not only is the reactivity provided in the catalytic reaction, but also the nitrogen element can react with the Lewis-acidic site of the zirconium phosphate through acid-base protons, so that the zirconium phosphate and the carbon nitride are connected through interaction; when the zirconium phosphate plays a flame-retardant role in the base material, the zirconium phosphate can quickly form carbon on the surface, gaps between the sheet layers are filled, a large number of micro-nano carbon cages are formed, a large number of base material degradation products are sealed in the micro-nano carbon cages, and the zirconium phosphate is sufficiently catalyzed and carbonized in a high-temperature oxygen-deficient environment; according to the invention, carbon nitride is connected in zirconium phosphate through acid-base proton catalysis, and the flame retardant effect is exerted in a micro-nano carbon cage formed by the zirconium phosphate solid acid effect, so that the carbon strength of the carbon cage can be improved, degradation products can be better sealed, and the flame retardant is more suitable for full catalytic carbonization of zirconium phosphate, thereby improving the flame retardant efficiency of the flame retardant.

Compared with the prior art, the invention has the beneficial effects that:

1) according to the invention, firstly, the alpha-zirconium phosphate is pre-supported by using the small molecular amine, and then the surfactant and the graphite-phase carbon nitride are inserted into the zirconium phosphate to form a composite intercalation-exfoliation structure, so that the formed phosphorus-nitrogen composite intercalation structure is beneficial to exerting the carbon-nitrogen-phosphorus-zirconium synergistic flame-retardant effect, the flame-retardant efficiency of the flame retardant can be obviously improved, and the stability of the obtained flame retardant is guaranteed.

2) The flame retardant disclosed by the invention has the advantages of higher flame retardant efficiency, excellent comprehensive performance, environmental friendliness, no pollution, good compatibility with resin and the like, capability of effectively considering other properties of the material (chemical stability, no toxicity, no corrosivity on a base material and the like of the material), simple related preparation method and wide applicability.

Drawings

FIG. 1 is a graph showing the fire resistance of an intumescent fire-retardant coating obtained in example 1 of the present invention.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.

In the following examples, the zirconium phosphates used are all α -zirconium phosphates; the structural formula of the adopted Gemini surfactant is CH₃(CH₂)₁₇-NHBr-(CH₂)₄-NHBr-(CH₂)₁₇CH₃。