Preparation method and application of polybutylene succinate oil-absorbing foam

Abstract

The application discloses a preparation method of a polybutylene succinate oil-absorbing foam, comprising the following steps: S1, melt spinning of raw materials containing polybutylene succinate and high-melting-point second phase to obtain a composite fiber; S2, hot pressing of the composite fiber in step S1 to obtain a composite material containing micro-nano fibers; and S3, supercritical foaming of the composite material in step S3 to obtain the polybutylene succinate oil-absorbing foam. The preparation method can obtain high-multiple foam without reducing the opening.

Description

Technical Field

[0001] This application relates to a polybutylene succinate oil-absorbing foam, its preparation method and application, belonging to the technical fields of environmental protection and oil-absorbing materials. Background Technology

[0002] Oil-absorbing materials play a crucial role in the treatment of oily wastewater and marine oil spills. Current technologies primarily use traditional non-degradable polymers as the matrix for oil-absorbing materials, leading to solvent pollution during preparation and potential secondary pollution after use. Supercritical foaming technology is an environmentally friendly foam preparation technique, producing foams with high cell density and small cell size. Polybutylene succinate (PBS) possesses good biodegradability but low melt strength. Chain extension and branching methods can improve the expandability of PBS, but the improved high melt strength compromises its easy-opening characteristics. Currently, it is difficult to obtain high-expansion foam from PBS without reducing its open-cell structure. Summary of the Invention

[0003] According to one aspect of this application, in view of the problem and shortcomings of the prior art that PBS is difficult to obtain high-expansion foam without reducing the opening size, a method for preparing polybutylene succinate oil-absorbing foam is provided.

[0004] The technical solution adopted in this application is as follows:

[0005] A method for preparing polybutylene succinate oil-absorbing foam includes the following steps:

[0006] S1. Melt spinning of raw materials containing polybutylene succinate and a high-melting-point second phase to obtain composite fibers;

[0007] S2. The composite fibers from step S1 are hot-pressed to obtain a composite material containing micro and nanofibers.

[0008] S3. The composite material in step S3 is supercritically foamed to obtain the polybutylene succinate oil-absorbing foam.

[0009] Optionally, in step S1, the content of polybutylene succinate in the raw material is 80-99.5 wt%, and the content of the high-melting-point second phase is 0.5-20 wt%.

[0010] Optionally, in step S1, the content of polybutylene succinate in the raw material is selected from any value among 80wt%, 82wt%, 84wt%, 86wt%, 88wt%, 90wt%, 92wt%, 94wt%, 96wt%, 98wt%, and 99.5wt%, or any range between the two.

[0011] Optionally, in step S1, the content of the high-melting-point second phase in the raw material is selected from any value among 0.5wt%, 1wt%, 2wt%, 4wt%, 6wt%, 8wt%, 10wt%, 12wt%, 14wt%, 16wt%, 18wt%, and 20wt%, or any range between the two.

[0012] In step S1, the melting point of the polybutylene succinate is t1, and the melting point of the high-melting-point second phase is t2.

[0013] t2-t1≥30℃.

[0014] Optionally, in step S1, the high-melting-point second phase is a polymer.

[0015] Optionally, in step S1, the high-melting-point second phase is selected from at least one of polypropylene, polylactic acid, polyhydroxyalkanoate, and polyvinylidene fluoride.

[0016] After melt spinning, micron-fibers or nanofibers of a high-melting-point second-phase matrix are formed in the polybutylene succinate polymer matrix of the composite fiber. The polybutylene succinate polymer matrix in the composite fiber melts, but the micron-fibers or nanofibers of the high-melting-point second-phase matrix in the polymer composite fiber do not melt.

[0017] Optionally, in step S1, the diameter of the composite fiber is 100–300 μm.

[0018] Optionally, in step S2, the diameter of the micro / nanofiber is 0.05–10 μm.

[0019] Optionally, in step S2, the diameter of the micro / nanofiber is 0.1–0.2 μm.

[0020] Optionally, in step S2, the thickness of the composite material is 0.5 to 5 mm.

[0021] Optionally, in step S1, the raw material further includes processing aids.

[0022] Optionally, the processing aid is selected from antioxidants.

[0023] Optionally, in step S1, the temperature of the melt spinning is 145–190°C.

[0024] Melt spinning involves two steps: melt blending and hot stretching, to obtain composite fibers.

[0025] Optionally, in step S2, the temperature t3 of the hot pressing process;

[0026] t1 < t3 < t2.

[0027] Optionally, in step S2, the temperature t3 of the hot pressing is 130-140°C.

[0028] Optionally, in step S3, the supercritical foaming conditions are: under the condition of supercritical carbon dioxide at a pressure of 10-24 MPa as the supercritical fluid, saturation and depressurization foaming are performed.

[0029] Optionally, the pressure in the supercritical foaming conditions is selected from any value of 10 MPa, 12 MPa, 14 MPa, 16 MPa, 18 MPa, 20 MPa, 22 MPa, or 24 MPa, or any range between the two.

[0030] Optionally, the saturation conditions are: maintaining pressure at a first-stage temperature of 100–140°C for 5–120 min, and then maintaining pressure at a second-stage temperature of 80–100°C for 0–120 min.

[0031] Optionally, the depressurization foaming time is 0.3 to 30 seconds.

[0032] Optionally, the temperature of the first stage is selected from any value of 100℃, 110℃, 120℃, 130℃, 140℃, or any range between two.

[0033] Optionally, the holding time at the first stage temperature can be selected from any value among 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, and 120 min, or any value between the two.

[0034] Optionally, the second stage temperature is selected from any value among 80℃, 85℃, 90℃, 95℃, and 100℃, or a range between any two.

[0035] Optionally, the holding time at the second stage temperature is selected from any value among 0 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, and 120 min, or any value between the two.

[0036] According to another aspect of this application, the application of polybutylene succinate oil-absorbing foam prepared by the above preparation method as an oil-absorbing material in the treatment of oily wastewater and marine oil spills is also provided.

[0037] In this application, PBS refers to polybutylene succinate.

[0038] In this application, PLA refers to polylactic acid.

[0039] In this application, PP refers to polypropylene.

[0040] The beneficial effects that this application can produce include:

[0041] The method for preparing polybutylene succinate oil-absorbing foam provided in this application yields oil-absorbing foam with high open porosity and highly interconnected pore structure. High-expansion foam is obtained without reducing the open porosity. It has a significant adsorption capacity for different solvents or oils, reaching a maximum adsorption capacity of 90% within 1 minute. The adsorption capacity does not decrease significantly after 20 cycles, and it can effectively separate oil-water mixtures. Attached Figure Description

[0042] Figure 1 The images shown are scanning electron microscope (SEM) images of the cross-sectional morphology of the PBS / PLA composite materials prepared in Examples 1-3 of this invention, where (a) is at 5000x magnification and (b) is at 10000x magnification.

[0043] Figure 2 The images shown are scanning electron microscope (SEM) images of the cross-sectional morphology of the foam prepared in Example 2 of this invention, where (a) is at 100x magnification and (b) is at 1000x magnification.

[0044] Figure 3 The foam prepared in Example 2 of this invention has the ability to absorb oil from carbon tetrachloride after 20 cycles.

[0045] Figure 4 The process by which foam prepared in Example 2 of the present invention selectively adsorbs carbon tetrachloride (a) and cyclohexane (b) from water.

[0046] Figure 5 The images shown are scanning electron microscope (SEM) images of the cross-sectional morphology of the PBS / PP composite materials prepared in Examples 4-6 of this invention.

[0047] Figure 6 This is a scanning electron microscope image of the cross-sectional morphology of the foam prepared in Example 7 of the present invention.

[0048] Figure 7 The images shown are scanning electron microscope (SEM) images of the cross-sectional morphology of the PBS / PLA composite materials prepared in Examples 8-10 of this invention. Detailed Implementation

[0049] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0050] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased commercially, including PBS (TH803S) with a melting point of 114°C, purchased from Lanshan Tunhe Technology Co., Ltd.

[0051] For performance testing of foam:

[0052] Foam density was measured using the water displacement method; open area ratio was measured using the gas specific gravity bottle method; cell size was obtained from scanning electron microscopy images; oil absorption capacity was the mass ratio of the foam with the skin removed before and after immersing it in oil / solvent for at least 1 hour.

[0053] Examples 1-3

[0054] 99 wt% PBS and 1 wt% PLA were blended using a twin-screw extruder at 170°C and 20 rpm. The extrudate was then hot-stretched to obtain composite fibers with a thickness of 200 μm. The composite fibers were then pressed into a plate at 140°C and 10 MPa to obtain a sample with a thickness of 1 mm. The PLA fiber size in the 1 mm PBS / PLA composite material was approximately 100 nm. The cross-sectional morphology of the foamed sample is shown below. Figure 1 As shown.

[0055] The obtained 1mm composite board was placed in a high-pressure autoclave, and supercritical carbon dioxide was used. The pressure was maintained at 20 MPa and 110℃ for 1.5 hours. The temperature was then lowered to the corresponding second temperature in Table 1 and maintained for 15 minutes. Then, the pressure was released and foamed within 0.5 seconds to obtain polybutylene succinate oil-absorbing foam.

[0056] Table 1. Foam performance at different second temperatures

[0057] Second temperature ℃ 90 95 100 <![CDATA[Foam density g / cm 3 > 0.040 0.033 0.051 Foaming ratio 31.5 38.2 24.7 Opening ratio % 97.2 98.4 96.6 Cell size (μm) 18.9 22.4 20.3 Foam water contact angle ° 113.4 115.9 110.1

[0058] The resulting foam density was 0.033-0.051 g / cm³. 3 The open porosity is 97.2%-98.4%, the cell size is 18.9-22.4μm, the cell walls are broken, the cell structure is highly interconnected, the foam water contact angle is 110.1-115.9°, and the foam carbon tetrachloride contact angle becomes zero within a few milliseconds, achieving wetting.

[0059] The foam density was lowest at a foaming temperature of 95℃. The SEM image of the foam cells at 95℃ is shown below. Figure 2 As shown in Table 2, the foam with the lowest density has an adsorption capacity of 19.2-50.4 g / g for different solvents or oils. It reaches its maximum adsorption capacity of 90% within 1 minute, and its adsorption capacity does not significantly decrease after 20 cycles. Figure 3 As shown in the test, the foam can effectively separate oil-water mixtures, such as... Figure 4 As shown.

[0060] Table 2 shows the adsorption capacity for different solvents or oils.

[0061] <![CDATA[CCl4]]> 1.60 50.4±2.5 silicone oil 0.96 30.2±1.3 Peanut oil 0.94 26.8±1.3 Ethyl acetate 0.90 26.4±1.2 n-Hexane 0.66 19.2±0.4 Cyclohexane 0.78 24.1±1.1 97# gasoline 0.74 23.2±1.4 0# diesel 0.85 26.8±1.1

[0062] Examples 4-6

[0063] 98wt% PBS, 2wt% PP, and 0.5 phr antioxidant were blended using a twin-screw extruder at 175℃ and 20 rpm. The extrudate was hot-stretched to obtain composite fibers of 200 μm. The composite fibers were then pressed into plates at 140℃ and 10 MPa to obtain samples with a thickness of 2 mm. The fiber sizes in the SEM images of the composite material were statistically analyzed. The PP fiber size was approximately 180 nm. Figure 5 As shown.

[0064] The obtained 2mm composite board was placed in a high-pressure autoclave, and supercritical carbon dioxide was used. The pressure was 20 MPa and 110℃ for 1.5 hours. The temperature was then lowered to 90℃ and held for 10-20 minutes. The pressure was then released and foamed within 0.5 seconds to obtain polybutylene succinate oil-absorbing foam.

[0065] Table 3. Foam performance at different insulation times when the second temperature is 90℃.

[0066] Insulation time (min) 10 15 20 <![CDATA[Foam density g / cm 3 > 0.064 0.041 0.141 Foaming ratio 16.7 30.7 8.9 Opening ratio % 95.2 96.9 89.8 Cell size (μm) 20.4 21.6 15.3 Foam water contact angle ° 109.1 113.1 116.2

[0067] The resulting foam density was 0.041-0.141 g / cm³. 3 The foam exhibits an open porosity of 89.8%-96.9%, a pore size of 15.3-21.6 μm, highly interconnected pore structure, and a foam-water contact angle of 109-117°. Testing revealed that the foam possesses a maximum adsorption capacity of 37.5 g / g for carbon tetrachloride. The adsorption capacity for different solvents or oils is directly proportional to the density of the solvent or oil, and the adsorption capacity did not significantly decrease after 20 cycles.

[0068] Example 7

[0069] 90wt% PBS and 10wt% PLA were blended using a twin-screw extruder at 170℃ and 30rpm. The extrudate was then hot-stretched to obtain 120μm composite fibers. The composite fibers were then oriented and pressed at 140℃ and 10MPa to obtain a sample with a thickness of 1mm.

[0070] The obtained 1mm composite board was placed in a high-pressure autoclave, and supercritical carbon dioxide was used. The pressure was maintained at 18 MPa and 115℃ for 2 hours. The temperature was then lowered to 95℃ and maintained for 15 minutes. The pressure was then released and foamed within 1 second to obtain polybutylene succinate oil-absorbing foam.

[0071] The resulting foam density was 0.263 g / cm³. 3 The foam cells are open and oriented, and the cells are interconnected. The cross-section of the foamed sample is as follows: Figure 6 As shown.

[0072] Examples 8-10

[0073] 97 wt% PBS and 3 wt% PLA were blended using a twin-screw extruder at 175°C and 30 rpm. The extrudate was then hot-stretched to obtain composite fibers with a thickness of 200 μm. The composite fibers were then pressed into a plate at 140°C and 10 MPa to obtain a sample with a thickness of 1 mm and a fiber diameter of approximately 100 nm. The cross-sectional image of the foamed sample is shown below. Figure 7 As shown.

[0074] The obtained 1mm composite board was placed in an autoclave and pressurized at 20 MPa and 110°C for 30 minutes using supercritical carbon dioxide. The temperature was then reduced to the corresponding second temperature in Table 4 at a cooling rate of 3°C / min. The pressure was then released and foamed within 0.5 seconds to obtain polybutylene succinate oil-absorbing foam.

[0075] Table 4. Foam performance at different second temperatures

[0076] Second temperature ℃ 80 85 90 <![CDATA[Foam density g / cm 3 > 0.240 0.050 0.089 Foaming ratio 5.3 25.2 14.2 Opening ratio % 84.3 96.8 94.0 Cell size (μm) 12.1 19.3 20.1

[0077] The resulting foam density was 1.12-0.05 g / cm³. 3 Among the foams produced by foaming at 85℃, the foaming ratio was the highest, reaching 25.2, with a water contact angle of 107°. The foam produced at 85℃ exhibited an adsorption capacity of 12.7-32.5 g / g for the different solvents listed in Table 2. The foam produced at 85℃ effectively separated stratified oil-water mixtures.

[0078] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing polybutylene succinate oil-absorbing foam, characterized in that, Includes the following steps: S1. A raw material containing polybutylene succinate and a high-melting-point second phase is melt-spun to obtain composite fibers; the melting point of the polybutylene succinate is t1, the melting point of the high-melting-point second phase is t2, and t2-t1≥30℃; the high-melting-point second phase is selected from at least one of polypropylene, polylactic acid, polyhydroxyalkanoate, and polyvinylidene fluoride. S2. The composite fibers from step S1 are hot-pressed to obtain a composite material containing micro and nanofibers. S3. The composite material in step S2 is supercritically foamed to obtain the polybutylene succinate oil-absorbing foam.

2. The preparation method according to claim 1, characterized in that, In step S1, the content of polybutylene succinate in the raw material is 80~99.5wt%, and the content of high melting point second phase is 0.5~20wt%.

3. The preparation method according to claim 1, characterized in that, In step S1, the diameter of the composite fiber is 100~300μm; In step S2, the diameter of the micro / nanofiber is 0.05~10μm; The thickness of the composite material is 0.5~5mm.

4. The preparation method according to claim 1, characterized in that, In step S1, the raw materials also include processing aids.

5. The preparation method according to claim 1, characterized in that, In step S1, the temperature of the melt spinning is 145~190℃.

6. The preparation method according to claim 1, characterized in that, In step S2, the temperature t3 of the hot pressing process; t1 < t3 < t2.

7. The preparation method according to claim 1, characterized in that, In step S3, the conditions for supercritical foaming are: under the condition of supercritical carbon dioxide at a pressure of 10~24 MPa as supercritical fluid, saturation and depressurization foaming are performed.

8. The preparation method according to claim 7, characterized in that, The saturation conditions are: holding the pressure at a first stage temperature of 100~140℃ for 5~120min, and then holding the pressure at a second stage temperature of 80-100℃ for 0~120min; The depressurization and foaming time is 0.3~30s.

9. The application of polybutylene succinate oil-absorbing foam prepared by the preparation method according to any one of claims 1 to 8 as an oil-absorbing material in the treatment of oily wastewater and marine oil spills.

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