Patent Grant
11339538
The present application claims priority to Chinese Patent Appl. No. 201910654832.8 to Lu et al., filed Jul. 19, 2019 and entitled “Nano TiO2-Doped Anti-Ultraviolet Para-Aramid Nano Paper and Preparation Method Thereof”, and incorporates its disclosure herein by reference in its entirety.
The disclosure belongs to the technical field of nano paper, and relates to nano TiO2-doped anti-ultraviolet para-aramid nano paper and a preparation method thereof.
A para-aramid paper-based material is a two-dimensional sheet composite material which is prepared by a paper-making wet process based on para-aramid short cut fiber and para-aramid fibrid as raw materials. Due to light weight, high strength, good insulation property, high temperature resistance, flame retardancy and other features, the para-aramid paper-based material is widely used in the fields of aerospace, telecommunication, rail traffic and the like. However, there are two fatal disadvantages in the application process of aramid fiber materials: one of the two fatal disadvantages that the fiber surface is smooth, the active groups are less, and the surface wettability is poor, so as to result in that the binding strength between the fiber and other materials is poor, and then the overall performance of the material is affected; the other of the two fatal disadvantages is that the aramid fiber is a light-sensitive material (an amide bond on a molecular main chain is easy to break), but the aramid fiber is exposed to sunlight in most cases during the application, the aramid fiber itself has poor UV resistance, which will seriously affect the further application of materials in the long run.
The object of the disclosure is to overcome the disadvantages of the above prior art to provide nano TiO2-doped Anti-ultraviolet para-aramid nano paper and a preparation method thereof. The method is simple in process and does not harm fiber itself, can effectively improve mechanical strength, interface binding performance and processability of a base material and promotes the UV resistance of para-aramid fiber.
In order to achieve the above object, the disclosure is achieved by adopting the following technical solution:
Provided is nano TiO2-doped anti-ultraviolet para-aramid nano paper, and the para-aramid nano paper is doped with nano TiO2; the surface of the aramid nano fiber in the para-aramid nano paper contains C═O and N—H functional groups.
The further improvements of the disclosure are as follows:
Preferably, the average diameter of nano TiO2 in the para-aramid nano paper is 115 nm.
Provided is a preparation method of nano TiO2-doped anti-ultraviolet para-aramid nano paper, comprising the following steps:
Step 1, mixing KH-550, anhydrous ethanol and water, uniformly stirring and adjusting the pH value to 3-5 to obtain KH-550 solution; mixing nano TiO2, water and anhydrous ethanol and ultrasonically dispersing to obtain nano TiO2 dispersion; mixing the nano TiO2 dispersion with the KH-550 solution, uniformly stirring, and centrifuging to obtain a first centrifuged product; re-dispersing the first centrifuged product into dewatered and anhydrous ethanol mixed solution, and centrifuging again; and repeatedly dispersing the centrifuged product into mixed solution of water and anhydrous ethanol, and centrifuging, repeating the above steps for several times, and drying the final centrifuged product to obtain powdery modified nano TiO2;
Step 2, mixing DMSO, para-aramid fibrid and KOH to obtain mixed solution A, and stirring the mixed solution A at room temperature until the color of the mixed solution A is dark red, so as to obtain ANF suspension; and
Step 3, adding water in the ANF suspension to obtain defibered ANF suspension; ultrasonically dispersing the powdery modified nano TiO2 in water to obtain ultrasonically dispersed nano TiO2 solution; mixing the ultrasonically dispersed nano TiO2 solution with the defibered ANF suspension, and uniformly stirring to obtain mixed solution B, wherein the mass concentration of nano TiO2 in the mixed solution B is 2%˜10%; carrying out suction filtration, squeezing and drying on the mixed solution to obtain the nano TiO2-doped anti-ultraviolet para-aramid nano paper.
Preferably, in Step 1, the mixing volume ratio of KH-550 to anhydrous ethanol to water is 1:(85-95):(5-15).
Preferably, wherein in Step 1, the mixing ratio of nano TiO2 to anhydrous ethanol to water is 1 g:(8.8-13.5) mL:(0.7-1.7) mL.
Preferably, in Step 1, the mixing ratio of nano TiO2 dispersion to KH-550 solution is 1:(8-10).
Preferably, in Step 1, the times of centrifugation is 3-10.
Preferably, in Step 2, the mixing ratio of DMSO to para-aramid fibrid to KOH is (450-550) mL:1 g:(1-2) g.
Preferably, in Step 2, the stirring time of the mixed solution A is 7-10 days.
Preferably, in Step 3, the amount of water added in the ANF suspension is more than 5 times the volume of the ANF suspension.
Compared with the prior art, the disclosure has the following beneficial effects:
The disclosure discloses nano TiO2-doped anti-ultraviolet para-aramid nano paper, the para-aramid nano paper is doped with nano TiO2, and C═O and N—H functional groups are exposed out of the surface of the aramid nano fiber in the para-aramid nano paper so that the functional groups are connected with nano TiO2; as an ultraviolet absorbent, nano TiO2 has a good absorption effect on UV, so it improves the UV resistance of the aramid paper-based material; in the disclosure, since active groups are present on the surface of the para-aramid nano fiber, the interface binding performance and processability of the paper-based material are enhanced, and the nano TiO2-doped anti-UV para-aramid nanopaper material has excellent property.
The disclosure also discloses a preparation method of nano TiO2-doped anti-UV para-aramid nano paper. In the preparation method, first, nano TiO2 is modified by KH-550 to graft a hydrophobic long chain on the surface of nano TiO2, so as to reduce its surface energy, the modified nano TiO2 has good dispersivity, is not easy to agglomerate, and is convenient to disperse in nano paper in the next step. Through treatment of para-aramid fibrid with DMSO/KOH, deprotonation occurs in this system to remove hydrogen at the position of amido bond and destroy the original hydrogen bond structure in the aramid fiber, so that aramid fiber is dissolved and then aramid nano fiber is formed, the exposed C═O and N—H groups are obtained. Meanwhile, the method does not damage the fiber itself. After modified TiO2 and nano fiber are mixed, the nano TiO2-doped anti-UV para-aramid nano paper is prepared. The method is simple in preparation process, and the nano TiO2 which is low in price, green, non-toxic and excellent in property is selected as the UV absorbent, which meets the requirements of environmental protection.
Further, KH-550 and nano TiO2 are respectively dissolved or dispersed through mixed solution of anhydrous ethanol and mixed to obtain KH-550 and nano TiO2 dispersion. In the mixing process, KH-550 can effectively modify nano TiO2.
Further, the centrifuged product is washed by the mixed solution of ethanol and water to sufficiently remove KH-550 which is remained on the surface of nano TiO2 after modification.
Further, deprotonation is carried out on the para-aramid fibrid is carried out through KOH, and the whole process lasts for about one week. H on the amide bond is removed to destroy a large number of hydrogen bonds in the molecular chain of the aramid fiber, so that the macroscopic fiber becomes nano fiber.
wherein, (a) is the original ANF paper, and (b) is the nano composite paper added with 4% of nano TiO2;
The disclosure will be described in detail in combination with drawings and embodiments. The disclosure discloses a nano TiO2-doped anti-ultrasonic para-aramid nano paper and a preparation method thereof. The para-aramid nano paper is doped with nano TiO2, the average size of nano TiO2 is 115 nm, and the surface of the aramid nano fiber in the para-aramid nano paper contains a large number of C═O and N—H functional groups which have certain activity and can be connected with hydroxyl on the surface of nano TiO2 by means of a hydrogen bond. Raw materials are prepared before preparation, including para-aramid fibrid (ANF), nano TiO2, potassium hydroxide (KOH), dimethyl sulfoxide (DMSO), γ-aminopropyltriethoxy silane (KH-550), anhydrous ethanol and deionized water; the preparation method specifically comprises the following steps:
Step 1: Modification of Nano TiO2;
Anhydrous ethanol, deionized water and KH-550 are taken, and mixed (a mixing volume ratio of (85-95):(5-15):1) and stirred at 60-70° C. and then put in a three-neck flask, and the pH value is adjusted to 3-5 with hydrochloric acid and sodium hydroxide solution, so as to obtain KH-550 solution; nano TiO2, anhydrous ethanol and deionized water are mixed (a mixing ratio of 1 g:(8-13.5) mL:(0.7-1.7) mL) and ultrasonically dispersed for 5 min to obtain ultrasonically dispersed nano TiO2 suspension; the dispersed nano TiO2 suspension is poured into the three-neck flask, wherein the mixing volume ratio of the nano TiO2 suspension to KH-550 solution is 1:(8-10), the nano TiO2 suspension and the KH-550 solution are stirred for 1 h at a constant speed at 60-70° C. to obtain the mixed solution, the mixed solution is centrifuged to obtained the centrifuged product, and then the centrifuged product is dispersed in the mixed solution of deionized water and anhydrous ethanol again, and the above steps are repeated for several times with total centrifugation for 3-10 times; KH550 on the surface of the modified nano TiO2 is removed by repeated centrifugation, and the final centrifuged product is dried in a 100° C. oven for 6 hours to obtain the modified nano TiO2 which is grinded into powder for later user.
Step 2: Preparation of ANF Suspension
According to the proportion of (450-550) mL:1 g:(1:2) g, DMSO, para-aramid fibrid and KOH are mixed to obtain mixed solution A, and then the mixed solution A is stirred at room temperature for 7-10 days until the solution was dark red to obtain ANF suspension.
Step 3: Preparation of Nano TiO2-Doped Para-Aramid Nano Paper
1) ANF suspension is taken and defibered by adding water, wherein the addition amount of water is more than 5 times of the volume of ANF suspension, so that DMSO is diluted with water in a solvent;
2) the powdery modified nano TiO2 is dispersed in water to obtain the ultrasonically dispersed nano TiO2 solution; the ultrasonically dispersed nano TiO2 solution and the defibered ANF suspension are uniformly stirred to obtain mixed solution B; the mass concentration of nano TiO2 in the mixed solution B is 2%˜10%; the mixed solution B is filtered at reduced, pressed and dried to obtain the nano TiO2-doped para-aramid nano paper.
Step 1: 90 mL of anhydrous ethanol, 10 mL of deionized water and 1 mL of KH-550 were taken, mixed and stirred at 60° C. and the put in a three-neck flask, and the pH value was adjusted to about 4 with hydrochloric acid and sodium hydroxide solution; 1 g of nano TiO2 was weighed and added into mixed solution of 1 mL of deionized water and 9 mL of anhydrous ethanol, the above mixture was ultrasonically dispersed at a high speed for 5 min to obtain ultrasonically dispersed nano TiO2 suspension; the dispersed nano TiO2 was poured into the three-neck flask, the mixing volume ratio of nano TiO2 suspension to KH-550 solution was 1:8, and the mixed solution was obtained after stirring at 60° C. for 1 h at a constant speed. After centrifugation, the above mixed solution was dispersed again in the mixed solution of deionized water and anhydrous ethanol, such the steps were repeated for 5 times, and the above dispersion was dried in an oven at 100° C. for 6 h and then grinded, so that the modified TiO2 solution was obtained;
Step 2: 500 mL of DMSO solution was taken and added with 1.0 g of para-aramid fibrid and 1.5 g of KOH and then stirred at room temperature for 7 days, until the solution is dark red, and ANF suspension was obtained.
Step 3: 100 mL of ANF solution was taken and added with 500 mL of water to be defibered; the modified TiO2 solution prepared in step 1 was ultrasonically dispersed in water to obtain the ultrasonically dispersed nano-TiO2 solution; the ultrasonically dispersed nano TiO2 solution and the defibered ANF suspension were uniformly stirred to obtain the mixed solution B; the mass concentration of nano TiO2 in the mixed solution B was 4%; the mixed solution B was filtered at reduced pressure, squeezed and dried to obtain nano TiO2-doped para-aramid nano paper.
The SEM graph of the nano TiO2-doped para-aramid nano paper prepared in this embodiment is seen in
It can be seen from the XRD image in
It can be seen from
Step 1: 85 mL of anhydrous ethanol, 10 mL of deionized water and 1 mL of KH-550 were taken, mixed and stirred at 60° C. and the put in a three-neck flask, the pH value was adjusted to about 4 with hydrochloric acid and sodium hydroxide solution; 1 g of nano TiO2 was weighed and added into mixed solution of 1.2 mL of deionized water and 10 mL of anhydrous ethanol, the above mixture was ultrasonically dispersed at a high speed for 5 min to obtain ultrasonically dispersed nano TiO2 suspension; the dispersed nano TiO2 was poured into the three-neck flask, the mixing volume ratio of nano TiO2 suspension to KH-550 solution was 1:10, and the mixed solution was obtained after stirring at 70° C. for 1 h at a constant speed. After centrifugation, the above mixed solution was dispersed again in the mixed solution of deionized water and anhydrous ethanol, such the steps were repeated for 3 times, the above dispersion was dried in an oven at 100° C. for 6 h and then grinded, so that the modified TiO2 solution was obtained;
Step 2: 450 mL of DMSO solution was taken and added with 1.0 g of para-aramid fibrid and 2 g of KOH and then stirred at room temperature for 8 days, until the solution is dark red, and ANF suspension was obtained.
Step 3: 100 mL of ANF solution was taken and added with 600 mL of water to be defibered; the modified TiO2 solution prepared in step 1 was ultrasonically dispersed in water to obtain the ultrasonically dispersed nano-TiO2 solution; the ultrasonically dispersed nano TiO2 solution and the defibered ANF suspension were uniformly stirred to obtain the mixed solution B; the mass concentration of nano TiO2 in the mixed solution B was 6%; the mixed solution B was filtered at reduced pressure, pressed and dried to obtain nano TiO2-doped para-aramid nano paper.
Step 1: 90 mL of anhydrous ethanol, 15 mL of deionized water and 1 mL of KH-550 were taken, mixed and stirred at 65° C. and the put in a three-neck flask, the pH value was adjusted to about 5 with hydrochloric acid and sodium hydroxide solution; 1 g of nano TiO2 was weighed and added into mixed solution of 1.7 mL of deionized water and 10 mL of anhydrous ethanol, the above mixture was ultrasonically dispersed at a high speed for 5 min to obtain ultrasonically dispersed nano TiO2 suspension; the dispersed nano TiO2 was poured into the three-neck flask, the mixing volume ratio of nano TiO2 suspension to KH-550 solution was 1:9, and the mixed solution was obtained after stirring at 60° C. for 1 h at a constant speed. After centrifugation, the above mixed solution was dispersed again in the mixed solution of deionized water and anhydrous ethanol, such the steps were repeated for 10 times, and the above dispersion was dried in an oven at 100° C. for 6 h and then grinded, so that the modified TiO2 solution was obtained;
Step 2: 480 mL of DMSO solution was taken and added with 1.0 g of para-aramid fibrid and 1 g of KOH and then stirred at room temperature for 9 days, until the solution is dark red, and ANF suspension was obtained.
Step 3: 100 mL of ANF solution was taken and added with 800 mL of water to be defibered; the modified TiO2 solution prepared in step 1 was ultrasonically dispersed in water to obtain the ultrasonically dispersed nano-TiO2 solution; the ultrasonically dispersed nano TiO2 solution and the defibered ANF suspension were uniformly stirred to obtain the mixed solution B; the mass concentration of nano TiO2 in the mixed solution B was 8%; the mixed solution B was filtered at reduced pressure, pressed and dried to obtain nano TiO2-doped para-aramid nano paper.
Step 1: 95 mL of anhydrous ethanol, 5 mL of deionized water and 1 mL of KH-550 were taken, mixed and stirred at 60° C. and the put in a three-neck flask, the pH value was adjusted to about 3 with hydrochloric acid and sodium hydroxide solution; 1 g of nano TiO2 was weighed and added into mixed solution of 0.7 mL of deionized water and 13.5 mL of anhydrous ethanol, the above mixture was ultrasonically dispersed at a high speed for 5 min to obtain ultrasonically dispersed nano TiO2 suspension; the dispersed nano TiO2 was poured into the three-neck flask, the mixing volume ratio of nano TiO2 suspension to KH-550 solution was 1:8, and the mixed solution was obtained after stirring at 60° C. for 1 h at a constant speed. After centrifugation, the above mixed solution was dispersed again in the mixed solution of deionized water and anhydrous ethanol, such the steps were repeated for 6 times, and the above dispersion was dried in an oven at 100° C. for 6 h and then grinded, so that the modified TiO2 solution was obtained;
Step 2: 470 mL of DMSO solution was taken and added with 1.0 g of para-aramid fibrid and 1.5 g of KOH and then stirred at room temperature for 10 days, until the solution is dark red, and ANF suspension was obtained.
Step 3: 100 mL of ANF solution was taken and added with 600 mL of water to be defibered; the modified TiO2 solution prepared in step 1 was ultrasonically dispersed in water to obtain the ultrasonically dispersed nano-TiO2 solution; the ultrasonically dispersed nano TiO2 solution and the defibered ANF suspension were uniformly stirred to obtain the mixed solution B; the mass concentration of nano TiO2 in the mixed solution B was 2%; the mixed solution B was filtered at reduced pressure, pressed and dried to obtain nano TiO2-doped para-aramid nano paper.
Step 1: 88 mL of anhydrous ethanol, 10 mL of deionized water and 1 mL of KH-550 were taken, mixed and stirred at 60° C. and the put in a three-neck flask, the pH value was adjusted to about 4 with hydrochloric acid and sodium hydroxide solution; 1 g of nano TiO2 was weighed and added into mixed solution of 1 mL of deionized water and 8.8 mL of anhydrous ethanol, the above mixture was ultrasonically dispersed at a high speed for 5 min to obtain ultrasonically dispersed nano TiO2 suspension; the dispersed nano TiO2 was poured into the three-neck flask, the mixing volume ratio of nano TiO2 suspension to KH-550 solution was 1:10, and the mixed solution was obtained after stirring at 60° C. for 1 h at a constant speed. After centrifugation, the above mixed solution was dispersed again in the mixed solution of deionized water and anhydrous ethanol, such the steps were repeated for 6 times, the above dispersion was dried in an oven at 100° C. for 6 h and then grinded, so that the modified TiO2 solution was obtained;
Step 2: 550 mL of DMSO solution was taken and added with 1.0 g of para-aramid fibrid and 2 g of KOH and then stirred at room temperature for 8 days, until the solution is dark red, and ANF suspension was obtained.
Step 3: 100 mL of ANF solution was taken and added with 600 mL of water to be defibered; the modified TiO2 solution prepared in step 1 was ultrasonically dispersed in water to obtain the ultrasonically dispersed nano-TiO2 solution; the ultrasonically dispersed nano TiO2 solution and the defibered ANF suspension were uniformly stirred to obtain the mixed solution B; the mass concentration of nano TiO2 in the mixed solution B was 10%; the mixed solution B was filtered at reduced pressure, pressed and dried to obtain nano TiO2-doped para-aramid nano paper.
The above descriptions are only preferred embodiments of the disclosure but not intended to limit the disclosure. Any modifications, equivalent substitutions, improvements and the like made without departing from the spirit and principle of the disclosure are all included within the scope of protection of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201910654832.8 | Jul 2019 | CN | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20040009727 | Lin | Jan 2004 | A1 |
| 20090142567 | Kanakarajan | Jun 2009 | A1 |
| 20110281034 | Lee | Nov 2011 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20210017713 A1 | Jan 2021 | US |
