A kind of rutile titanium dioxide nanorod blended modified polyethylene fiber and its preparation method

Abstract

This invention discloses a polyethylene fiber modified with rutile titanium dioxide nanorods and its preparation method, relating to the field of polymer material modification and fiber preparation technology. The fiber is obtained by melt spinning of mixed polyethylene (C-PE) and rutile TiO2 nanorods modified with KH-570. The mass fraction of TiO2 nanorods is 1%-5%, preferably 3%. The resulting fiber has a uniform distribution of TiO2 nanorods, high tensile strength, and a UPF value as high as 649.04. After 60 days of outdoor aging in distilled water, sunlight, and seawater in summer, and 288 hours of UV aging, the strength retention rate is significantly higher than that of pure PE fiber, and the heat distortion temperature is increased to 98.46℃. The process of this invention is stable and suitable for preparing high-performance outdoor polyethylene fiber materials.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification and fiber preparation technology, specifically to a polyethylene fiber modified by blending rutile titanium dioxide nanorods and its preparation method. Background Technology

[0002] Polyethylene (PE) fiber is widely used in packaging materials, agricultural films, fishing nets, and outdoor textiles due to its excellent chemical stability, low density, low cost, and good processability.

[0003] However, when PE fibers are exposed to ultraviolet rays, moisture and heat cycling in outdoor environments for a long time, molecular chain breakage is likely to occur, resulting in a significant decrease in mechanical properties, surface cracking and shortened service life. This defect seriously limits its promotion and application in outdoor scenarios.

[0004] To improve the anti-aging properties of polymers, researchers have attempted to add inorganic nanoparticles, such as titanium dioxide (TiO2) and zinc oxide, to the polymer matrix. Currently, spherical TiO2 nanoparticles are commonly used, but they are prone to agglomeration, have poor compatibility with the polymer matrix, and may become stress concentration points, leading to a decline in the mechanical properties of the composite material. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To overcome the shortcomings of existing technologies, a polyethylene fiber modified by blending rutile titanium dioxide nanorods and its preparation method are proposed. The fiber exhibits excellent anti-aging properties, good mechanical properties, high UV protection coefficient, and good thermal stability.

[0007] (II) Technical Solution

[0008] The present invention is achieved through the following technical solution: The present invention proposes a polyethylene fiber modified by rutile titanium dioxide nanorod blend and its preparation method. The polyethylene fiber is made by melt spinning of mixed polyethylene (C-PE) and rutile TiO2 nanorods modified by silane coupling agent, wherein the mass fraction of rutile TiO2 nanorods is 1%-5%.

[0009] Furthermore, the mixed polyethylene (C-PE) comprises 35% ultra-high molecular weight polyethylene (molecular weight 1 million) and 65% high-density polyethylene (molecular weight 100,000).

[0010] Furthermore, the rutile TiO2 nanorods have an average length of 3 μm, an average diameter of 180 nm, and an aspect ratio of 17:1.

[0011] Furthermore, the silane coupling agent is coupling agent KH-570.

[0012] Furthermore, the rutile TiO2 nanorods have a mass fraction of 3%.

[0013] A method for preparing polyethylene fibers modified with rutile titanium dioxide nanorods includes the following steps: (1) Preparation of rutile TiO2 nanorods; (2) Surface modification was performed on it using silane coupling agent KH-570; (3) The modified nanorods were mixed with mixed polyethylene and melt-extruded by a twin-screw extruder to obtain masterbatch; (4) The masterbatch is blended with mixed polyethylene and melt-spun to obtain blended fibers.

[0014] Furthermore, the preparation of the rutile TiO2 nanorods includes uniformly mixing anatase titanium dioxide powder and potassium carbonate powder in a molar ratio of 3:2, heating and stirring, followed by drying, calcination, acid washing, potassium removal, and secondary calcination.

[0015] Furthermore, the surface modification method involves drying the rutile TiO2 nanorods to completely remove moisture, adding an ethanol dispersion, sonicating, then heating and stirring, and finally sonicating again while adding KH-570 ethanol dispersion dropwise. The mixed solution is then heated and stirred, and centrifuged to obtain a precipitate. The precipitate is washed with ethanol and then thoroughly dried.

[0016] Furthermore, the melt extrusion temperature is 190°C, and the screw speed is 20-30 r / min.

[0017] (III) Beneficial Effects

[0018] Compared with the prior art, the present invention has the following advantages: This invention relates to a method for preparing polyethylene fiber modified with rutile titanium dioxide nanorods, which involves using high aspect ratio rutile TiO2 nanorods, surface modified with KH-570, and then uniformly dispersed in a polyethylene matrix (see...). Figure 3 (b) Titanium element distribution), with no obvious agglomeration, avoiding the problem of spherical nanoparticles easily becoming stress concentration points; when the nanorod content is 3%, the tensile strength of the blended fiber reaches 131.52 MPa, and the ultraviolet protection factor (UPF) reaches 533.49 (see Figure 10 (d) significantly higher than unmodified PE fiber (UPF=36.54); anti-aging performance was significantly improved. After 60 days of outdoor distilled water immersion, sunlight exposure, seawater immersion, and 288 hours of accelerated UV aging, the strength retention rates of fibers with 3% nanorod content reached 94.5%, 93.9%, 88.0%, and 93.7%, respectively (see Figure 6-9The content of the cellulose content is much higher than that of C-PE fiber (79.6%, 73.9%, 85.3%, and 85.5%), resulting in enhanced thermal stability and an increase in heat distortion temperature from 85.75℃ to 98.46℃ (see...). Figure 12 (d)(e)), the maximum thermal decomposition temperature increased from 478.96℃ to 484.54℃, and the processing performance was good. Attached Figure Description

[0019] Figure 1 SEM image (a) and FTIR spectra (b) of rutile TiO2 nanorods before and after modification.

[0020] Figure 2 The rheological properties of blended fibers with different contents are shown in the following figures: (a) complex viscosity, (b) storage modulus, (c) loss modulus, and (d) loss factor.

[0021] Figure 3 The cross-sectional EDS elemental distribution diagrams ((b)Ti,(c)C,(d)O) and surface SEM images ((e)C-PE,(f)C-PE / TiO2) of the fiber blend containing 3% nanorods are shown.

[0022] Figure 4 Optical micrographs (left) and diameter distribution histograms (right) of blended fibers with different nanorod contents (0%-5%).

[0023] Figure 5 The effect of rutile TiO2 nanorod (a) and nanoparticle (b) content on fiber tensile strength.

[0024] Figure 6 The strength retention rate of fibers with different nanorod contents after aging in outdoor distilled water for 0-60 days in summer.

[0025] Figure 7 The strength retention rate of fibers with different nanorod contents after aging for 0-60 days under outdoor sunlight exposure in summer.

[0026] Figure 8 The strength retention rate of fibers with different nanorod contents after aging in outdoor seawater for 0-60 days in summer.

[0027] Figure 9 The strength retention rate of fibers with different nanorod contents after UV accelerated aging for 0-288 hours.

[0028] Figure 10 UV protection properties of fibers with different nanorod contents: (a) transmittance, (b) T UVA (c)T UVB , (d) UPF value.

[0029] Figure 11TGA curves (a) and DTG curves (b) for C-PE and C-PE / TiO2 blended fibers.

[0030] Figure 12 DMA curves ((a) storage modulus, (b) loss modulus, (c) loss factor) and TMA curves ((d) C-PE, (e) C-PE / TiO2) for C-PE and C-PE / TiO2 blended fibers. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] The mixed polyethylene material, abbreviated as C-PE, consists of 35% ultra-high molecular weight polyethylene (100w molecular weight) and 65% high-density polyethylene (10w molecular weight). Anatase titanium dioxide powder and potassium carbonate powder are uniformly mixed at a molar ratio of Ti:K = 3:2. The mixture is heated at 100℃ and stirred at high speed for eight hours to form a viscous slurry. It is then dried in a 100℃ oven to completely dehydrate the slurry. The resulting lumps are ball-milled to revert to powder form. The ball-milled powder is calcined at 1000℃ for 8 hours, then cooled to room temperature in the furnace to allow for complete reaction. The calcined material is then mixed with water at a mass ratio of 1:10, boiled at 100℃ for 6 hours, and then cooled, dehydrated, and dried. The boiled material and water were mixed at a mass ratio of 1:20 and heated to 65°C. Then, a 1 mol / L hydrochloric acid solution was added until the pH of the solution stabilized at 1.5 ± 0.5. After the pH stabilized for 1 hour, the solution was filtered and washed. This process was repeated until the potassium ion concentration in the solution was <3.0 × 10⁻⁶. -1 The solution was dehydrated and dried, and finally calcined at 700℃ for 3 h to obtain rutile TiO2 nanorods.

[0033] Rutile TiO2 nanorods were dried in an oven at 80°C for 6 hours to completely remove moisture. 100 mL of a 1% (w / w) TiO2 nanorod ethanol dispersion was sonicated for 10 minutes, then heated and stirred at 70°C for 2 hours, and finally sonicated again for 10 minutes. While sonicating, 2.5 mL of a 5% (w / w) KH-570 ethanol dispersion was added dropwise. After the KH-570 ethanol dispersion was completely added, the mixture was heated and stirred at 70°C for 6 hours. Finally, the mixture was centrifuged at 10000 r / min, and the precipitate was collected. The precipitate was washed three times with ethanol and then dried thoroughly in an oven at 80°C to obtain modified rutile TiO2 nanorods.

[0034] To ensure moisture removal, C-PE was vacuum dried at 60℃ for 6 hours. Then, 40g of the sample was mixed evenly with TiO2 and melt-extruded using a twin-screw extruder at 190℃ and 20-30 rpm to obtain masterbatch. After a second drying at 65℃ for 1 hour, the masterbatch and C-PE were melt-blended at 190℃ (20-30 r / min) to finally obtain samples with rutile titanium dioxide nanorods of 1%, 2%, 3%, 4% and 5% by mass.

[0035] The above samples were tested and experimented on: 1. Microstructure and surface-modified structure analysis of rutile TiO2 nanorods Figure 1 (a) SEM images of rutile TiO2 nanorods are shown. The rutile TiO2 nanorods exhibit a distinct rod-like morphology, with an average length of approximately 3 μm and an average diameter of approximately 180 nm, corresponding to an aspect ratio of approximately 17:1. Figure 1 (b) Infrared spectra of rutile TiO2 nanorods before and after modification are shown. Both samples are in the range of 800 cm⁻¹. -1 and 3400cm -1 The characteristic broadband bands in the vicinity are attributed to the Ti–O–Ti lattice vibrations and surface hydroxyl groups, respectively. The modified rutile TiO2 nanorods exhibit a broadband band at 2900 cm⁻¹. -1 and 1630cm -1 New absorption peaks appear at 1080 cm⁻¹, corresponding to C–H and C=C stretching vibrations, respectively. -1 The appearance of a new peak nearby is due to the stretching vibration of Si–O–Ti, confirming that KH-570 has been successfully grafted onto the TiO2 surface through chemical bonding.

[0036] 2. The effect of rutile TiO2 nanorods on the rheological properties of C-PE / TiO2 was analyzed using rheological testing. For example... Figure 2 As shown, the results indicate that after adding 3% TiO2, its complex viscosity, storage modulus, and loss modulus are slightly higher than those of C-PE. However, the loss factor (tanδ) remains basically unchanged, reflecting the stability of the material. The slight fluctuations in rheological properties have little impact on macroscopic processing. Subsequent spinning experiments confirmed that rutile TiO2 nanorods did not interfere with the fiber forming process, and their spinning stability is highly consistent with that of C-PE, fully meeting the processing requirements.

[0037] 3. Figure 3EDS spectra of the cross-section of rutile titanium dioxide nanorod blend fibers containing 3% TiO2 were displayed. Observations show that the titanium element is relatively uniformly distributed without large-sized agglomerates, confirming that the KH-570 surface modification treatment effectively improved the dispersion of TiO2 in the matrix. The oxygen element distribution pattern is highly consistent with that of titanium. Carbon, a major component of the polyethylene matrix, is uniformly distributed in the sample. Figure 3 (e) and Figure 3 (f) The surface morphology of the fibers was compared. Figure 3 (e) shows that the C-PE fiber surface is smooth and dense with no characteristic texture, exhibiting typical characteristics of unmodified thermoplastic polymer fibers. In contrast, the surface roughness of the C-PE / TiO2 blend fiber is increased.

[0038] 4. Figure 4 The microstructure and diameter distribution of blended fibers with different rutile TiO2 nanorod contents are shown. Figure 4 (af) The optical microscope image shown on the left (scale bar: 50 μm) shows that all samples formed a continuous and defect-free fibrous structure, which indicates that the melt spinning process has high stability.

[0039] 5. Figure 5 (a) shows that the tensile strength of the blended fibers with added TiO2 nanorods initially fluctuates slightly, then decreases. The strength fluctuation is small when the rutile TiO2 nanorod content is 1-3%, reaching 131.52 MPa at 3%, but the strength begins to decrease at higher contents (4-5%). Conversely, as... Figure 5 As shown in (b), the tensile strength of fibers containing rutile TiO2 nanoparticles generally decreased with increasing content, from 133.44 MPa to 94.99 MPa at 5%. Therefore, rutile TiO2 nanorods were used in all subsequent experiments.

[0040] 6. Figure 6 The tensile strength and strength retention of the blended fibers were demonstrated after 60 days of aging in distilled water outdoors during summer. The fibers were TiO2-free. Figure 6 (a) After 60 days of aging, the tensile strength decreased to 106.17 MPa, corresponding to a retention rate of 79.6%. In contrast, when the TiO2 content was 3%, ( Figure 6 (d) The fiber retains a strength of 124.28 MPa after the same aging cycle, achieving a retention rate of up to 94.5%.

[0041] 7. Figure 7 This demonstrates the effect of natural sunlight exposure on the tensile strength and strength retention of blended fibers. Fibers without TiO2 ( Figure 7(a) After 60 days of irradiation, the tensile strength decreased from 133.44 MPa to 98.67 MPa, with a retention rate of only 73.9%. This significant decrease indicates that photo-oxidation severely degrades fiber properties. In contrast, fibers containing 3% TiO2 ( Figure 7 (d) After 60 days of exposure, the strength of the rutile TiO2 nanorods was still 123.55 MPa, with a retention rate of 93.9%. These results indicate that the rutile TiO2 nanorods enhanced the anti-aging ability of the fibers by absorbing and scattering ultraviolet rays. Among all samples, the 3% TiO2 content showed the best protective effect.

[0042] 8. Figure 8 This study demonstrates the changing trends of tensile strength and strength retention rate of blended fibers with different rutile TiO2 nanorod contents after aging in outdoor seawater for varying periods during summer. After 60 days of seawater aging, the strength of C-PE fibers decreased from 133.44 MPa to 113.82 MPa, with a strength retention rate of 85.3%. However, the addition of 3% TiO2 nanorods increased the strength retention rate to 88.0% (115.73 MPa). This indicates that TiO2 nanorods effectively enhance the fiber's resistance to seawater aging.

[0043] 9. Figure 9 The changes in tensile strength of the fiber under UV aging conditions are shown. For C-PE fiber ( Figure 9 (a) After 288 hours of irradiation, the tensile strength decreased to 114.14 MPa, corresponding to a retention rate of 85.5%. In contrast, the fiber containing 3% TiO2 ( Figure 9 (d) The rate of strength decline slowed significantly, decreasing from 131.52 MPa to 123.28 MPa, maintaining a retention rate as high as 93.7%. This trend indicates that the excellent photostability of rutile TiO2 nanorods effectively delayed fiber degradation induced by ultraviolet radiation, with a 3% content exhibiting the best anti-aging performance.

[0044] 10. For example Figure 10 (a) shows that with increasing rutile TiO2 nanorod content, the transmittance in the 300–400 nm band decreases significantly. The average TUVA decreases from 23.85% (C-PE) to 3.8% at 1% rutile TiO2 nanorod content, and further to 1.32% at 5% rutile TiO2 nanorod content; TUVB decreases to below 0.12% when the rutile TiO2 nanorod content is ≥1%. Figure 10As shown in (d), the UPF increased from 36.54 (C-PE) to 533.49 with a rutile TiO2 nanorod content of 3%, and reached 649.04 with a rutile TiO2 nanorod content of 5%, indicating that adding rutile TiO2 nanorods can improve the UV protection performance of the fiber. The C-PE / TiO2 blend fiber containing 3% rutile TiO2 nanorods achieved the optimal balance between UV protection performance and tensile strength.

[0045] 11. Figure 11 The TG and DTG curves of C-PE fiber and C-PE / TiO2 blend fiber (3% rutile TiO2 nanorod content) are shown. Generally, the temperature at which the fiber mass loss reaches 5% (T5%) is considered the initial thermal decomposition temperature of the fiber. As shown in the table below, after adding 3% rutile TiO2 nanorods, T5% increased to 450.87℃, and the maximum thermal decomposition rate temperature (Tmax) of the blend fiber increased from 478.96℃ to 484.54℃. The heat resistance index (THRI) of the blend fiber typically indicates the highest temperature at which the fiber can maintain its original physical and mechanical properties and chemical stability at high temperatures. THRI can be calculated using the following formula. As shown in the table, the trend of THRI is consistent with that of T5%.

[0046] T5% and T30% represent the temperatures at which fiber mass loss reaches 5% and 30%, respectively.

[0047]

[0048] 12. Figure 12 (a) shows the variation of energy storage modulus with temperature. It can be seen that the energy storage modulus of C-PE / TiO2 blended fibers (rutile TiO2 nanorod content of 3%) is always higher than that of C-PE fibers. Figure 12 (b) The relationship between loss modulus and temperature is shown. The loss modulus of C-PE / TiO2 blended fiber is also higher than that of C-PE fiber. Figure 12 (c) The loss factors (tanδ) of the two fibers were compared. The peak tanδ of the C-PE / TiO2 fiber was lower than that of the C-PE fiber. This decrease in peak value indicates that the polymer chain segment movement was restricted after the addition of rutile titanium dioxide nanorods. Thermomechanical analysis (TMA) was used to demonstrate the thermal deformation behavior of the fibers, such as... Figure 12 (d) and Figure 12 As shown in (e), by comparing the two figures, it can be seen that the heat distortion temperature (Td) of the C-PE / TiO2 blend fiber increased from 85.75℃ to 98.46℃, and the softening temperature (Ts) increased from 128.89℃ to 129.18℃. This proves that rutile TiO2 nanorods enhance the heat resistance of the fiber.

[0049] In summary, this study successfully prepared C-PE / TiO2 blended fibers with improved anti-aging properties by adding KH570 modified rutile TiO2 nanorods to C-PE via melt spinning. Compared with C-PE, the rheological properties of the blended melt did not change significantly, and the C-PE / TiO2 blended fibers had uniform diameter. Among samples with TiO2 content of 1-5%, fibers containing 3% TiO2 exhibited excellent UV protection (UPF value of 533.49), tensile strength (131.52 MPa), and anti-aging ability. When the rutile TiO2 nanorod content was 3%, the nanorods were uniformly distributed in the blended fibers. After 60 days of distilled water immersion, sunlight exposure, seawater immersion, and 288 hours of UV aging treatment in summer, the strength retention rates of C-PE / TiO2 blended fibers were 94.5%, 93.9%, 88.0%, and 93.7%, respectively, all higher than those of C-PE fibers (79.6%, 73.9%, 85.3%, and 85.5%). The blended fibers also exhibited excellent heat resistance, with the heat distortion temperature increasing from 85.75℃ to 98.46℃.

[0050] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the inventive concept should fall within the protection scope of the present invention. All technical contents for which protection is sought in this invention are fully described in the claims.

Claims

1. A rutile titania nanorod blend-modified polyethylene fiber, characterized by: The polyethylene fiber is made by melt spinning of mixed polyethylene (C-PE) and rutile TiO2 nanorods modified with silane coupling agent, wherein the mass fraction of rutile TiO2 nanorods is 1%-5%.

2. The rutile titania nanorod blend-modified polyethylene fiber according to claim 1, characterized by: The mixed polyethylene (C-PE) comprises 35% ultra-high molecular weight polyethylene with a molecular weight of 1 million and 65% high-density polyethylene with a molecular weight of 100,000.

3. The rutile titania nanorod blend-modified polyethylene fiber according to claim 1, characterized by: The rutile TiO2 nanorods have an average length of 3 μm, an average diameter of 180 nm, and an aspect ratio of 17:

1.

4. The rutile titania nanorod blend-modified polyethylene fiber according to claim 1, characterized by: The silane coupling agent is coupling agent KH-570.

5. The rutile titania nanorod blend-modified polyethylene fiber according to claim 1, characterized by: The mass fraction of the rutile TiO2 nanorods is 3%.

6. A process for the preparation of a rutile titania nanorod blend modified polyethylene fiber, characterized in that Includes the following steps: (1) Preparation of rutile TiO2 nanorods; (2) Surface modification was performed on it using silane coupling agent KH-570; (3) The modified nanorods were mixed with mixed polyethylene and melt-extruded by a twin-screw extruder to obtain masterbatch; (4) The masterbatch is blended with mixed polyethylene and melt-spun to obtain blended fibers.

7. The process for the preparation of rutile titania nanorod-blended modified polyethylene fibers according to claim 6, characterized by: The preparation of the rutile TiO2 nanorods includes uniformly mixing anatase titanium dioxide powder and potassium carbonate powder in a molar ratio of 3:2, heating and stirring, followed by drying, calcination, acid washing, potassium removal, and secondary calcination.

8. The process for the preparation of rutile titania nanorod blend modified polyethylene fibers as claimed in claim 6, wherein: The surface modification method involves drying rutile TiO2 nanorods to completely remove moisture, adding ethanol dispersion, sonicating, then heating and stirring, and finally sonicating again while adding KH-570 ethanol dispersion dropwise. The mixed solution is then heated, stirred, and centrifuged to obtain a precipitate. The precipitate is washed with ethanol and then thoroughly dried.

9. The method for preparing polyethylene fiber modified with rutile titanium dioxide nanorods according to claim 6, characterized in that: The melt extrusion temperature is 190℃, and the screw speed is 20-30 r / min.

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