Treatment method of polyethylene fiber precursor
By sonicating the polyethylene fiber precursor, dimethyl sulfoxide aqueous solution dissolves some molecules inside the fiber, solving the problem of insufficient research on the internal structure of the polyethylene fiber precursor in the prior art, achieving clear observation and control of the internal structure of the fiber, and improving the mechanical properties of the fiber.
Patent Information
- Application Number
- CN202411508678.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-03-04
AI Technical Summary
In the prior art, there is little research on the internal structure of polyethylene fiber precursors, which makes it difficult to control the arrangement of molecular chains and stereoregularity, affecting the mechanical properties of the fibers.
By sonicating the polyethylene fiber precursor, dimethyl sulfoxide aqueous solution dissolves some molecules inside the fibers and retains a stable tissue structure, thereby providing more structural information.
This method can clearly observe the internal structure of the polyethylene fiber precursor, provide more structural information, help control the arrangement and stereoregulation of the molecular chains, guide the subsequent production process, and produce polyethylene fibers with better performance.
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Figure CN119553496A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of polymer material technology, and in particular to a method for processing a polyethylene fiber precursor. Background Art
[0002] Polyethylene fiber has the advantages of high specific strength, large specific modulus, low density, corrosion resistance, friction resistance, and fatigue resistance. It is widely used in aerospace, military and civilian fields.
[0003] The polyethylene fiber precursor is obtained by spraying the polyethylene solution through the spinneret and then solidifying it in the first coagulation bath to become a solid. It is the precursor material for preparing polyethylene fibers. The polyethylene fiber precursor is made into polyethylene fibers by stretching heat treatment. At present, a lot of research has been done on the structure and preparation process of polyethylene fiber precursors at home and abroad. It is found that the organizational structure of polyethylene fiber precursors has an important influence on the physical and chemical changes that occur during the subsequent heat treatment process. The structure is closely related to the performance of polyethylene fibers. A polyethylene fiber precursor with high orientation and uniform structure is the prerequisite for obtaining high-performance fibers. The chemical structure of a series of molecular chains such as the structure, arrangement and stereoregularity of the polyethylene fiber chain has been fixed at the moment of formation, which directly affects the mechanical properties of polyethylene fibers. In the subsequent heat treatment process, the internal structure of the polyethylene fiber precursor will be retained until the fiber is formed, which will have an unadjustable effect on the density, strength and mechanical properties of the final polyethylene fiber. Therefore, studying the microstructure inside the polyethylene fiber precursor is conducive to controlling the arrangement of the molecular chains and guiding the subsequent production process, thereby producing polyethylene fibers with better performance. There are few studies on the internal structure of carbon fiber precursors at home and abroad, and there is almost no data available. Summary of the invention
[0004] In response to the problems existing in the prior art, an embodiment of the present application provides a method for processing a polyethylene fiber precursor. By utilizing the different solubilities of the crystalline and amorphous regions in the polyethylene fiber precursor, a solution is used under ultrasonic conditions to dissolve some of the molecules inside the fiber, thereby retaining a stable tissue structure and providing more structural information.
[0005] The method for processing a polyethylene fiber precursor provided in an embodiment of the present application comprises the following steps:
[0006] Step 1, degreasing, decontamination, drying, embedding, and slicing the polyethylene fiber precursor in sequence to obtain fiber slices;
[0007] Step 2, preparing a dimethyl sulfoxide aqueous solution with a concentration of 20% to 80%;
[0008] Step 3, after the fiber slices are covered with a carbon film, they are placed in the dimethyl sulfoxide aqueous solution for ultrasonic treatment;
[0009] Step 4, washing the slices after ultrasonic treatment with a dimethyl sulfoxide aqueous solution with a concentration of 20% to 70% and water in sequence.
[0010] In some embodiments, the embedding comprises:
[0011] Placing the polyethylene fiber precursor in an embedding hole of an embedding plate, wherein the embedding hole is pre-filled with an embedding medium;
[0012] Continue to fill the embedding medium into the embedding hole until the embedding hole is filled;
[0013] The embedding plate is placed in a vacuum oven for curing to obtain an embedded polyethylene fiber precursor.
[0014] In some embodiments, the embedding medium includes one or more of epoxy resin, phenolic resin, and acrylic resin.
[0015] In some embodiments, the embedding layer formed by the embedding medium has a thickness of 20 nm to 30 nm.
[0016] In some embodiments, the curing process includes: curing at 35° C. for 12 hours, curing at 45° C. for 12 hours, and curing at 55° C. for 48 hours.
[0017] In some embodiments, the fiber slice has a thickness of 65 nm to 75 nm.
[0018] In some embodiments, the ultrasonic treatment has an ultrasonic frequency of 15 kHz-20 kHz.
[0019] In some embodiments, the ultrasonic treatment time is 10 min-20 min.
[0020] In some embodiments, the temperature of the ultrasonic treatment is 70°C-80°C.
[0021] In some embodiments, the polyethylene fiber precursor is prepared by a melt spinning process. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0023] Figure 1 Schematic diagram of the preparation of longitudinal slices of polyethylene fiber precursor.
[0024] Figure 2The following are scanning electron microscope morphology images of the polyethylene fiber precursor structure before and after etching in some embodiments of the present application, wherein (a) is before etching and (b) is after etching.
[0025] Figure 3 This is a high-resolution transmission electron microscopy photograph of the unetched polyethylene fiber precursor slice in Comparative Example 1 of the present application.
[0026] Figure 4 This is a high-resolution transmission electron microscopy photograph of a longitudinal section of a polyethylene fiber precursor that has been fully etched in Example 3 of the present application. DETAILED DESCRIPTION
[0027] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating examples of the present application. In the accompanying drawings and the following description, at least some of the known structures and technologies are not shown to avoid unnecessary ambiguity in the present application; and, for clarity, the size of some structures may be exaggerated. In addition, the features, structures or characteristics described below may be combined in one or more embodiments in any suitable manner.
[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish an entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "multiple" is more than two. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only include those elements, but also include other elements not clearly listed, or also include elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the sentence "include..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.
[0029] In the process of preparing polyethylene fiber with polyethylene fiber precursor, the internal structure of the polyethylene fiber precursor will be retained until the fiber is formed, which will have an unadjustable impact on the density, strength and mechanical properties of the final polyethylene fiber. The internal structure of the polyethylene fiber precursor, such as the chemical structure of a series of molecular chains such as the structure, arrangement and stereoregularity of the polyethylene fiber chain, has been fixed at the moment of the formation of the polyethylene fiber precursor. Therefore, studying the internal structure of the polyethylene fiber precursor is conducive to controlling the arrangement of molecular chains in the polyethylene fiber precursor, which is used to understand the subsequent production process and produce polyethylene fibers with better performance. However, there is little research on the internal structure of polyethylene fibers in related technologies.
[0030] In order to solve the problems of the prior art, an embodiment of the present application provides a method for processing a polyethylene fiber precursor. By chemically treating the polyethylene fiber precursor, the internal structure of the polyethylene fiber precursor can be clearly observed, providing more structural information for the study of the polyethylene fiber precursor.
[0031] The embodiment of the present application provides a method for processing a polyethylene fiber precursor, comprising the following steps S10 to S40.
[0032] S10, sequentially degreasing, decontaminating, drying, embedding, and slicing the polyethylene fiber precursor to obtain fiber slices;
[0033] S20, preparing a dimethyl sulfoxide aqueous solution with a concentration of 20% to 80%;
[0034] S30, after the fiber slices are covered with carbon film, they are placed in a dimethyl sulfoxide aqueous solution for ultrasonic treatment;
[0035] S40, washing the slices after ultrasonic treatment with dimethyl sulfoxide aqueous solution having a concentration of 20% to 70% and water in sequence.
[0036] In the embodiments of the present application, the polyethylene fiber precursor can be purchased from the market or prepared by methods known in the art. For example, the polyethylene fiber precursor can be prepared by a melt spinning process. The polyethylene fiber precursor can be degreased, decontaminated and dried before being processed to remove oil stains and impurities on the surface of the polyethylene fiber precursor and reduce the influence of oil stains and impurities on the embedding process.
[0037] By embedding the polyethylene fiber precursor, the embedding layer can provide effective support for the polyethylene fiber precursor, and during the slicing process, polyethylene fiber slices of specified specifications can be obtained for subsequent etching treatment and observation and research of the internal structure, while preventing the polyethylene fiber precursor from disintegrating or dissolving and dispersing during the etching process and failing to obtain a complete slice tissue. In addition, after the polyethylene fiber precursor is embedded, a clear boundary can be provided for the polyethylene fiber precursor, and the interface of the internal structure of the polyethylene fiber precursor can be clearly distinguished after etching care, which is convenient for observing its internal structure.
[0038] In some embodiments, embedding the polyethylene fiber precursor includes: cutting the clean fiber precursor into 2-4 mm micro-segments, first dripping 3-4 drops of embedding medium into the embedding hole of the latex embedding plate, using tweezers to place the dispersed fibers vertically or parallel to the long axis of the embedding hole into the embedding hole, and then dripping resin until the embedding hole is filled. The embedding plate is placed in a vacuum oven for curing, curing at 35°C for 12 hours, curing at 45°C for 12 hours, and then curing at 55°C for 48 hours.
[0039] In some embodiments, the embedding medium includes one or more of epoxy resin, phenolic resin, and acrylic resin. The embedding medium can form a uniform and stable film layer to coat the surface of the polyethylene fiber precursor to form a stable embedding structure.
[0040] In some embodiments, additives may be added to the embedding medium to allow the embedding medium to solidify faster.
[0041] In some embodiments, the additive may include one or more of a curing agent, a toughening agent, and an accelerator.
[0042] In some embodiments, the curing agent includes one or more of dodecenyl succinic anhydride, p-hydroxybenzenesulfonic acid, and diethylaminopropylamine. The curing agent can promote the cross-linking and curing of the embedding medium to form a stable embedding layer.
[0043] In some embodiments, the toughening agent includes one or more of dibutyl phthalate, nano titanium dioxide, and polyvinyl butyral. The toughening agent can improve the strength of the embedding layer formed by the embedding medium, reduce cracking or damage of the embedding layer, and further improve the stability of the embedding structure.
[0044] In some embodiments, the accelerator includes one or more of 2,4,6-tris(dimethylaminomethyl)phenol, aminosulfonic acid, and N,N-dimethylaniline. The accelerator can increase the solidification rate of the embedding medium and improve the efficiency of the embedding process.
[0045] The embedded polyethylene fiber precursor is sliced to obtain polyethylene fiber precursor slices, wherein the polyethylene fiber precursor slices include at least one of transverse slices and longitudinal slices.
[0046] The slicing process can be performed using a slicer, and the thickness of the polyethylene fiber precursor slices can be 80nm-120nm, and can be optionally 90nm-110nm.
[0047] Reference Figure 1 , the embedded sample block can be trimmed first, then the sample block can be clamped with a clamp, the relative position of the knife and the sample block can be adjusted, and the slice thickness can be set to about 70nm. During the sample preparation process, the slice floats on the water surface. In order to better support the slice and prevent it from curling and deformation, a copper mesh is used as a support film. There is a thin carbon support film on the copper mesh. The time is about 10 minutes. After the obtained slice is close to the surface of the carbon film, it is taken out and placed on filter paper to automatically dry at room temperature.
[0048] The polyethylene fiber precursor slice is covered with a carbon film and then ultrasonically etched in a dimethyl sulfoxide aqueous solution to remove part of the tissue inside the polyethylene fiber precursor slice.
[0049] The solubility of the crystalline region and amorphous region in the polyethylene fiber precursor in the etching solution is different. Under the action of ultrasound, the etching solution can dissolve the unstable tissue part (amorphous region) inside the polyethylene fiber precursor, and the stable tissue part (fibril part, amorphous region) will be retained.
[0050] In some embodiments, the mass percentage concentration of the dimethyl sulfoxide aqueous solution may be 40%-70%.
[0051] In some embodiments, the ultrasound frequency of the ultrasound treatment is 15 kHz-20 kHz.
[0052] In some embodiments, the ultrasonic treatment time is 10 min-20 min.
[0053] In some embodiments, the temperature of the ultrasonic treatment is 70°C-80°C.
[0054] In some embodiments, after step S40, the polyethylene fiber precursor slices are further cleaned.
[0055] Optionally, the cleaning process includes: cleaning the polyethylene fiber precursor slices after the ultrasonic etching process using an etching solution with a mass percentage concentration of 30%-40% and deionized water in sequence.
[0056] Example
[0057] The present application is described below with reference to specific examples. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be obtained commercially.
[0058] Example 1
[0059] The etching solution is a dimethyl sulfoxide aqueous solution with a mass percent concentration of 20%.
[0060] Step 1: Degreasing, decontamination, drying, and embedding the surface of the polyethylene fiber precursor prepared by the melt spinning process, and slicing the embedded block using a microtome and a diamond knife to obtain transverse and longitudinal fiber ultra-thin slices with a thickness of 50 nm;
[0061] The embedding medium is epoxy resin, the curing agent is dodecenyl succinic anhydride, the toughening agent is dibutyl phthalate, and the accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.
[0062] Step 2: Using water as solvent, prepare a 20% dimethyl sulfoxide solution;
[0063] Step 3: Cover the longitudinal (transverse) slices obtained in step 1 with a carbon film and then clamp them into the dimethyl sulfoxide solution in step 2 and immerse them completely;
[0064] Step 4: Place the sample from step 3 in an ultrasonic cleaning machine with a water temperature of 65°C and an ultrasonic frequency of 15 khz for 5 minutes, then take out the sample and clean it with a 20% dimethyl sulfoxide solution and water.
[0065] The final sample was dried and observed and analyzed using a high-resolution transmission electron microscope. There were slight etching marks on the surface of the slice and the internal structure was not obvious.
[0066] Example 2
[0067] The etching solution is a dimethyl sulfoxide aqueous solution with a mass percent concentration of 30%.
[0068] Step 1: Degreasing, decontamination, drying, and embedding the surface of the polyethylene fiber precursor prepared by the melt spinning process, and slicing the embedded block using a slicer and a diamond knife to obtain transverse and longitudinal fiber ultra-thin slices with a thickness of 70 nm;
[0069] The embedding medium is phenolic resin, the curing agent is p-hydroxybenzenesulfonic acid, the toughening agent is nano titanium dioxide, and the accelerator is aminosulfonic acid.
[0070] Step 2: Using water as solvent, prepare a dimethyl sulfoxide solution with a concentration of 40%;
[0071] Step 3: Cover the longitudinal (transverse) slices obtained in step 1 with a carbon film and then clamp them into the dimethyl sulfoxide solution in step 2 and immerse them completely;
[0072] Step 4: Place the sample from step 3 in an ultrasonic cleaning machine with a water temperature of 68°C and an ultrasonic frequency of 16 khz for 7 minutes, then take out the sample and clean it with a 30% dimethyl sulfoxide solution and water.
[0073] The sample was dried and the morphology of the slices after etching was observed using a high-resolution transmission electron microscope, where obvious etching marks could be seen on the slices.
[0074] Example 3
[0075] The etching solution is a dimethyl sulfoxide aqueous solution with a mass percent concentration of 50%.
[0076] Step 1: Degreasing, decontamination, drying, and embedding the surface of the polyethylene fiber precursor prepared by the melt spinning process, and slicing the embedded block using a microtome and a diamond knife to obtain transverse and longitudinal fiber ultra-thin slices with a thickness of 90 nm;
[0077] The embedding medium is acrylic resin, the curing agent is diethylaminopropylamine, the toughening agent is polyvinyl butyral, and the accelerator is N, N-dimethylaniline.
[0078] Step 2: Using water as solvent, prepare a 50% dimethyl sulfoxide solution;
[0079] Step 3: Cover the longitudinal (transverse) slices obtained in step 1 with a carbon film and then clamp them into the dimethyl sulfoxide solution in step 2 and immerse them completely;
[0080] Step 4: Place the sample from step 3 in an ultrasonic cleaning machine with a water temperature of 72°C and an ultrasonic frequency of 18 kHz for 10 minutes, then take out the sample and clean it with a 40% dimethyl sulfoxide solution and water.
[0081] The sample was dried and the morphology of the sample after etching was observed using a high-resolution transmission electron microscope. It was found that there were obvious scratches on the slices and microfibril structures with a diameter of 20-30nm.
[0082] Example 4
[0083] The etching solution is a dimethyl sulfoxide aqueous solution with a mass percent concentration of 70%.
[0084] Step 1: Degreasing, decontamination, drying, and embedding the surface of the polyethylene fiber precursor prepared by the melt spinning process, and slicing the embedded block using a microtome and a diamond knife to obtain transverse and longitudinal fiber ultra-thin slices with a thickness of 100 nm;
[0085] The embedding medium is epoxy resin, the curing agent is p-hydroxybenzenesulfonic acid, the toughening agent is dibutyl phthalate, and the accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.
[0086] Step 2: Using water as solvent, prepare a dimethyl sulfoxide solution with a concentration of 70%;
[0087] Step 3: Cover the longitudinal (transverse) slices obtained in step 1 with a carbon film and then clamp them into the dimethyl sulfoxide solution in step 2 and immerse them completely;
[0088] Step 4: Place the sample from step 3 in an ultrasonic cleaning machine with a water temperature of 75°C and an ultrasonic frequency of 20 khz for 15 minutes, then take out the sample and clean it with a 50% dimethyl sulfoxide solution and water.
[0089] The sample was dried and the morphology of the sample after etching was observed using a high-resolution transmission electron microscope. Obvious etching marks were found on the slices. Microfibril structures with a diameter of 20-30nm and a thickness of about 8nm could be observed, which were arranged perpendicular to the fiber axis.
[0090] Example 5
[0091] The etching solution is a dimethyl sulfoxide aqueous solution with a mass percent concentration of 80%.
[0092] Step 1: Degreasing, decontamination, drying, and embedding the surface of the polyethylene fiber precursor prepared by the melt spinning process, and slicing the embedded block using a microtome and a diamond knife to obtain transverse and longitudinal fiber ultra-thin slices with a thickness of 100 nm;
[0093] The embedding medium is phenolic resin, the curing agent is diethylaminopropylamine, the toughening agent is dibutyl phthalate, and the accelerator is aminosulfonic acid.
[0094] Step 2: Using water as solvent, prepare a dimethyl sulfoxide solution with a concentration of 80%;
[0095] Step 3: Cover the longitudinal (transverse) slices obtained in step 1 with a carbon film and then clamp them into the dimethyl sulfoxide solution in step 2 and immerse them completely;
[0096] Step 4: Place the sample from step 3 in an ultrasonic cleaning machine with a water temperature of 75°C and an ultrasonic frequency of 20 khz for 15 minutes, then take out the sample and clean it with a 70% dimethyl sulfoxide solution and water.
[0097] The sample was dried and the morphology of the slices after etching was observed using a high-resolution transmission electron microscope. It was found that the slices had basically disappeared and the fibril structure could not be observed.
[0098] Comparative Example 1
[0099] No etching process is performed.
[0100] The present invention utilizes a solution under ultrasonic conditions to dissolve some molecules inside the fiber, dissolves unstable tissue structures through the solution, and highlights stable tissue structures, thereby providing more structural information.
[0101] Figure 2 It is a structural morphology diagram of the polyethylene fiber precursor, (a) is before etching, and (b) is after etching. From the figure, we can see that the surface of the unetched fiber is relatively smooth, smooth, dense, without grooves, and the cortex is not peeled off. After etching, the cortex of the polyethylene fiber precursor is peeled off, and the structure inside the cortex is revealed, showing a periodic grid structure as a whole, which is relatively dense.
[0102] Analyzing the results of Examples 1-5, under ultrasonic conditions, in dimethyl sulfoxide solutions with concentrations of 50% and 70%, the etching marks on the surface of the polyethylene fiber precursor slices are more obvious, and in a dimethyl sulfoxide solution with a concentration of 80%, the etching marks on the surface of the polyethylene fiber precursor slices basically disappear.
[0103] like Figure 3 Comparative Example 1 is a high-resolution transmission electron microscope photograph of a longitudinal section of a polyethylene fiber precursor that has not been etched. It can be seen that the internal structure of the polyethylene fiber precursor that has not been etched is dense and uniform.
[0104] like Figure 4 This is a high-resolution transmission electron microscopy photograph of the longitudinal section of the polyethylene fiber precursor that has been fully etched in Example 3. It can be seen from the figure that after ultrasonic etching, there are obvious etching marks on the surface of the section, and there is an obvious microfibril structure in the etched area, with a diameter of 20-30nm and a thickness of 8nm, which is arranged perpendicular to the fiber axis.
[0105] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A method for processing a polyethylene fiber precursor, characterized in that: The steps include: Step 1, degreasing, decontamination, drying, embedding, and slicing the polyethylene fiber precursor in sequence to obtain fiber slices; Step 2, preparing a dimethyl sulfoxide aqueous solution with a concentration of 20% to 80%; Step 3, after the fiber slices are covered with a carbon film, they are placed in the dimethyl sulfoxide aqueous solution for ultrasonic treatment; Step 4, washing the slices after ultrasonic treatment with a dimethyl sulfoxide aqueous solution with a concentration of 20% to 70% and water in sequence.
2. The method according to claim 1, characterized in that The embedding comprises: Placing the polyethylene fiber precursor in an embedding hole of an embedding plate, wherein the embedding hole is pre-filled with an embedding medium; Continue to fill the embedding medium into the embedding hole until the embedding hole is filled; The embedding plate is placed in a vacuum oven for curing to obtain an embedded polyethylene fiber precursor.
3. The method according to claim 2, characterized in that The embedding medium includes one or more of epoxy resin, phenolic resin and acrylic resin.
4. The method according to claim 2 or 3, characterized in that: The embedding layer formed by the embedding medium has a thickness of 20 nm to 30 nm.
5. The method according to claim 2, characterized in that: The curing treatment includes: curing at 35° C. for 12 hours, curing at 45° C. for 12 hours, and curing at 55° C. for 48 hours.
6. The method according to claim 1, characterized in that The thickness of the fiber slice is 65 nm to 75 nm.
7. The method according to claim 1, characterized in that The ultrasonic frequency of the ultrasonic treatment is 15kHz-20kHz.
8. The method according to claim 1, characterized in that: The ultrasonic treatment time is 10 min-20 min.
9. The method according to claim 1, characterized in that: The temperature of the ultrasonic treatment is 70°C-80°C.
10. The method for processing a polyethylene fiber precursor according to claim 1, characterized in that: The polyethylene fiber precursor is prepared by a melt spinning process.