High-temperature-resistant crystallization suction pipe and preparation method thereof

Abstract

The invention relates to a high temperature resistant crystallization straw and a preparation method thereof, and relates to the technical field of high polymer materials, the high temperature resistant crystallization straw comprises the following components by weight: 100 parts of PLLA, 5-15 parts of PDLA, 5-15 parts of PBS, 1-35 parts of a filler, and 0.1-4 parts of a processing aid; the processing aid comprises a GMA graft, a hydrolysis-resistant agent, an antioxidant and a nucleating agent; the GMA graft is prepared from at least one of GMA-EMA (Glycidyl Methacrylate-Ethyl Methacrylate) and GMA-EBA (Glycidyl Methacrylate- The PLLA and the PDLA form a high-melting-point stereocomplex crystal, and a high-temperature-resistant core foundation is laid; the brittleness of the PLLA is compensated by PBS, the impact resistance is improved, and the crystal structure is optimized; and cooperation of multi-phase interface chemical bonding and physical entanglement is realized through the GMA graft, and the system compatibility is improved, so that the thermal deformation resistance and the mechanical property of the straw are improved.

Description

Technical Field

[0001] This application relates to the technical field of polymer materials, specifically to a high-temperature resistant crystallizing pipette and its preparation method. Background Technology

[0002] With the increasing global awareness of environmental protection, the white pollution problem caused by traditional non-degradable plastic straws due to their difficulty in natural degradation has become increasingly prominent. As a core alternative to traditional plastic straws, the market demand for biodegradable straws continues to rise.

[0003] Currently, most biodegradable straws are made of poly-L-lactic acid (PLLA). PLLA is the preferred material for biodegradable straws due to its good biocompatibility, complete biodegradability, and renewability. However, PLLA has inherent defects such as slow crystallization rate and low crystallinity, which result in straws with poor high-temperature resistance. When in contact with everyday hot beverages, they are prone to softening, deformation, or even collapse, making it difficult to meet the usage requirements of hot beverage drinking scenarios. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a high-temperature resistant crystallizing pipette and its preparation method.

[0005] In a first aspect, this application provides a high-temperature resistant crystallizing pipette, which adopts the following technical solution: A high-temperature resistant crystallization pipette comprises the following components in parts by weight: 100 parts PLLA, 5-15 parts PDLA, 5-15 parts PBS, 1-35 parts filler, and 0.1-4 parts processing aid; The processing aids include GMA grafts, hydrolysis-resistant agents, antioxidants, and nucleating agents; The GMA graft includes at least one of GMA-EMA and GMA-EBA.

[0006] By adopting the above technical solution, PDLA, as a stereoisomer of PLLA, can form a stereocomposite crystal during processing when compounded with PLLA. Its melting point is much higher than that of ordinary PLLA spherulites, which can significantly improve the heat deformation temperature of the material and provide core support for the high-temperature performance of the straw. PBS has good biodegradability, toughness and heat resistance, which can make up for the brittleness of PLLA, improve the impact resistance of the straw and reduce the risk of straw breakage during use. Moreover, the crystallization characteristics of PBS can further optimize the crystal structure of the material and improve the overall heat resistance stability.

[0007] The epoxy groups in the grafted side chains of GMA grafts can undergo ring-opening esterification reactions with the terminal hydroxyl groups of PLLA, PDLA, and PBS to achieve chemical bonding. Meanwhile, the EMA and / or EBA backbones, due to their ester-containing structure and flexible adaptability, are not only well-compatible with PBS but also tightly bound to PLLA and PDLA through hydrogen bonding interactions. This precisely delivers and anchors the epoxy groups at the multiphase interface, forming a stable interface layer where chemical bonding and physical entanglement complement each other, significantly improving the system's compatibility. At the same time, the high molecular weight backbone of the GMA grafts makes them less volatile during high-temperature processing, which enhances the stability of their compatibility effect.

[0008] Preferably, the hydrolysis-resistant agent is carbodiimide.

[0009] Preferably, the hydrolysis-resistant agent is a polymeric carbodiimide.

[0010] By adopting the above technical solutions, PLLA, PDLA and PBS are all polyester polymer materials with a large number of ester bonds in their molecular chains. During high-temperature processing and long-term storage or use, they are easily affected by factors such as moisture, heat and oxygen, which can cause ester bond breakage and generate terminal carboxyl groups. The terminal carboxyl groups themselves have a strong catalytic effect, which will further accelerate the hydrolysis reaction of ester bonds, thus reducing the performance of the pipette.

[0011] Carbodiimide-based hydrolysis resistant agents contain active carbodiimide groups in their molecular structure. These groups can react with the terminal carboxyl groups of polyester molecular chains to generate stable acylurea structures, thereby effectively consuming the terminal carboxyl groups, blocking the autocatalytic cycle of the hydrolysis reaction, significantly inhibiting the hydrolytic degradation of the material, and improving the dimensional stability and performance durability of straws under high temperature and high humidity environments.

[0012] Among them, polymeric carbodiimide has a higher molecular weight and more active carbodiimide groups, resulting in better dispersibility in polymer systems. It is less prone to migration and volatilization, and can continuously exert its hydrolysis resistance throughout the entire life cycle of material processing and use. At the same time, the molecular chain of polymeric carbodiimide has a certain degree of flexibility, which can form physical entanglement with the flexible backbone of GMA grafts, further enhancing the bonding force of multiphase interfaces, thereby improving the compatibility and stability of the system, and thus ensuring the long-term stability of the straw's high-temperature resistance and mechanical properties.

[0013] Preferably, the nucleating agent includes at least one of acylhydrazine nucleating agents and organophosphate nucleating agents.

[0014] By employing the above technical solutions, the acylhydrazine group in the molecular structure of acylhydrazine nucleating agents can form hydrogen bonds with the terminal hydroxyl or carboxyl groups of PLLA, PDLA, and PBS molecular chains, efficiently providing crystal nucleation sites. The acylhydrazine group can also inhibit thermal degradation by anchoring the molecular chain end groups, further improving the processing stability and durability of the material. Furthermore, acylhydrazine nucleating agents can directionally induce the formation of stereocomposite crystals, strengthening the high-temperature core performance of the system. Similarly, organophosphate nucleating agents can specifically promote the formation of stereocomposite crystals between PLLA and PDLA, significantly improving the crystallinity and heat distortion temperature of the material.

[0015] Preferably, the filler comprises at least one of talc, mica, and hydrotalcite.

[0016] By adopting the above technical solutions, talc, mica, and hydrotalcite all have a layered structure, which can serve as heterogeneous nucleation sites to accelerate the crystallization of PLLA, improve crystallinity, and enhance mechanical properties. At the same time, through the barrier effect of their layers, they can reduce heat transfer and block the penetration of small molecules such as oxygen and moisture, further enhancing the material's heat deformation resistance and improving its aging resistance.

[0017] Preferably, the high-temperature resistant crystallizing straw further includes a toughening agent, said toughening agent including at least one of E-PCL and HB-PCL.

[0018] By adopting the above technical solutions, E-PCL contains a large number of flexible PCL blocks, and HB-PCL molecular chains contain a large number of flexible PCL branches. Both can form uniformly dispersed flexible microregions in a matrix with PLLA / PDLA stereocomposite crystals as the rigid framework and PBS as the auxiliary toughening phase. Among them, the ethylene oxide hydrophilic block (EO) of E-PCL can further enhance its dispersibility in the matrix and improve the uniformity of the distribution of flexible microregions. When the straw is impacted by external force, these flexible microregions can absorb the impact energy through molecular chain coiling and sliding, and quickly disperse the concentrated stress to the surrounding matrix, reducing the risk of stress concentration causing fracture and significantly improving the impact resistance and flexibility of the straw.

[0019] Meanwhile, both PCL segments are polyester structures, similar to the molecular structures of PLLA, PDLA, and PBS, exhibiting good thermodynamic compatibility. Furthermore, the hydroxyl groups at the ends of the molecular chains can form hydrogen bonds with the terminal carboxyl / hydroxyl groups of the straw material matrix, and can also undergo ring-opening esterification reactions with the epoxy groups in the GMA graft to achieve chemical bonding. This enhances interfacial bonding, reduces the risk of debonding from the matrix when the flexible phase is under stress, and ensures the stable performance of the toughening effect.

[0020] Furthermore, the hydroxyl groups on the molecular chains of E-PCL and HB-PCL can form hydrogen bonds with the hydroxyl groups on the filler surface and interact with nucleating agents in processing aids, acting as an "interfacial bridge" to anchor the filler and processing aids in the matrix. Through their strong interfacial bonding with the matrix, they can improve the overall melt viscosity and mechanical strength of the system, reduce the thermal motion of molecular chains, and further reduce the migration tendency of fillers and processing aids in high-temperature processing or hot use environments, thus ensuring the long-term stability of the pipette's high-temperature resistance and mechanical properties.

[0021] Preferably, the toughening agent includes E-PCL and HB-PCL.

[0022] Preferably, the mass ratio of E-PCL to HB-PCL is (7-8):(3-2).

[0023] By adopting the above technical solutions, the PC flexible block chains of E-PCL are long and regular, with excellent fluidity, and can form continuous flexible channels in the matrix, efficiently transferring and dispersing impact stress. Its EO hydrophilic blocks can improve its dispersibility in the matrix and enhance the continuity of the flexible channels. Meanwhile, HB-PCL has high steric hindrance and can serve as nodes in the flexible network, entangled with the block chains of E-PCL. Using E-PCL as the dominant element and doping with an appropriate amount of branched HB-PCL, a uniform and stable three-dimensional flexible network can be constructed while improving the continuity and toughening effect of the flexible microregions.

[0024] Meanwhile, the relatively regular arrangement of PCL blocks in E-PCL allows for the directional induction of stereocomposite crystal formation through hydrogen bonding, while branched HB-PCL restricts the excessive movement of PLLA and PDLA molecular chains through its steric hindrance effect, providing a stable environment for the growth of stereocomposite crystals. The combination of these two materials can improve the toughness of the material while further increasing the content and crystallinity of the stereocomposite crystals, thus achieving a simultaneous improvement in the toughness and high-temperature resistance of the straw.

[0025] Furthermore, E-PCL can form large-area hydrogen bonds with the hydroxyl groups on the filler surface through the hydroxyl groups on its molecular chain, while the hydrophilicity of the EO blocks enhances the dispersibility of the filler in the matrix, uniformly dispersing and anchoring the filler particles in the matrix. HB-PCL, on the other hand, forms a three-dimensional flexible network that runs through the matrix by intertwining its branched molecular structure with the high molecular weight backbone of the GMA graft, encapsulating the filler particles and processing aid molecules within it. By restricting their free movement through steric hindrance, it effectively inhibits the agglomeration and migration of fillers during extrusion, annealing, and other processing processes, as well as the precipitation and migration of processing aids during use such as contact with hot beverages and long-term storage. The two work synergistically to improve the safety of straws used in high-temperature environments.

[0026] Secondly, this application provides a method for preparing a high-temperature resistant crystallizing pipette, which adopts the following technical solution: A method for preparing a high-temperature resistant crystallizing pipette, comprising the following steps: S1. Mix the formulated amounts of PLLA, PDLA, PBS, fillers, and processing aids to obtain a mixture; S2. The mixture is sequentially extruded, cooled and cut, and annealed to obtain the high-temperature resistant crystallizing straw.

[0027] Preferably, the toughening agent is added to the mixture along with PLLA, PDLA, PBS, filler, and processing aids in S1.

[0028] In summary, this application has the following beneficial effects: This application establishes a high-melting-point stereocomposite crystal by forming PLLA and PDLA, laying the core foundation for high-temperature resistance; it utilizes PBS to compensate for the brittleness of PLLA, improves impact resistance, and optimizes the crystal structure; and it achieves synergistic chemical bonding and physical entanglement at the multiphase interface through GMA grafts, thereby improving the system compatibility and enhancing the heat deformation resistance and mechanical properties of the straw. This application uses carbodiimide, preferably polymeric carbodiimide, which consumes the end carboxyl groups of polyester, blocks the hydrolysis autocatalytic cycle, and significantly inhibits hydrolytic degradation. Because polymeric carbodiimide has good dispersibility and is not easy to migrate and volatilize, it can continuously play a hydrolysis resistance role throughout its entire life cycle. It can also enhance the interfacial bonding force of multiphase, further improve the stability of the system, and ensure the dimensional stability and performance durability of the straw under high temperature and high humidity environment. This application uses E-PCL and HB-PCL to form flexible micro-regions or three-dimensional flexible networks, which can efficiently absorb impact energy, disperse stress, and improve the impact resistance and flexibility of the straw. It has good compatibility with the matrix, which can ensure the stability of the toughening effect. In addition, the two can also anchor fillers and processing aids, and help increase the content of stereocomposite crystals, so as to achieve simultaneous improvement in toughness and high temperature resistance. Detailed Implementation

[0029] The raw materials in this application include the following: PLLA: Poly-L-lactic acid, using the commercially available product Darl-1 from Hubei Darli Chemical Co., Ltd.; PDLA: Poly-D-lactic acid, using a commercially available product from Zhongshan Dixin Chemical Co., Ltd. with CAS number 106989-11-1; PBS: Polybutylene succinate, using the commercially available product TH803S from Xinjiang Lanshan Tunhe Chemical Co., Ltd.; GMA-EMA: Ethylene-methyl acrylate-glycidyl methacrylate copolymer, using the commercially available product from Sumitomo Corporation of Japan with the brand name BF-7M; GMA-EBA: Ethylene-butyl acrylate-glycidyl methacrylate copolymer, using the commercially available product AX8750T from SK Corporation of South Korea; Carbodiimide: The commercially available product AW-700 from Guangzhou Yinyuan New Materials Co., Ltd. is used. Polymerized carbodiimide: The commercially available product with CAS number 151-51-9 from Wuhan Jixin Yibang Biotechnology Co., Ltd. is used; Antioxidant: The product used is a commercially available product with brand name 1010 from Jinan Juyang Chemical Technology Co., Ltd. Acylhydrazide nucleating agent: Commercially available product TMC-300 from Shanghai Changhui Chemical Co., Ltd. was used; Organophosphate nucleating agent: NP-508, a commercially available product from Hubei Weistin Technology Co., Ltd.; Talc powder: commercially available product with a particle size of 600 mesh from Qingdao Haishengyuan Minerals Co., Ltd.; Mica: Commercially available product with a particle size of 600 mesh from Shijiazhuang Runguang New Material Co., Ltd.; Hydrotalcite: The product used is a commercially available product with a particle size of 600 mesh from Jiangsu Bosite Chemical Technology Co., Ltd. E-PCL: Ethylene oxide-polycaprolactone copolymer, using the commercially available four-arm poly(ethylene oxide)-BLOCK-polycaprolactone product from Sigma-Aldrich (Shanghai) Trading Co., Ltd. DMPA: 2,2-Dimethylolpropionic acid, using a commercially available product with CAS number 4767-03-7.

[0030] Preparation Example The preparation method of HB-PCL (hyperbranched polycaprolactone) includes the following steps: A1. Mix 6.44 g of dry DMPA, 109.78 g of polycaprolactone, and 0.42 g of stannous octoate catalyst, and turn on magnetic stirring under a nitrogen atmosphere. Set the stirring speed to 500 r / min, the reaction temperature to 120℃, and react at a constant temperature for 2 h. A2. Then adjust the reaction vacuum to -0.09~-0.1 MPa, first raise the reaction temperature to 150℃ and react at a constant temperature for 4h, then raise the temperature again to 175℃ and react at a constant temperature for 6h, until the system becomes a transparent viscous liquid. After naturally cooling to room temperature, the crude HB-PCL product is obtained. A3. Dissolve the crude HB-PCL product in 200 mL of chloroform, and add 800 mL of anhydrous methanol at a rate of 1-2 drops / s under stirring to precipitate the product. Collect the pale yellow precipitate, wash it repeatedly with anhydrous methanol 3 times, and then transfer it to a vacuum drying oven. Set the temperature to 80℃ and the vacuum degree to -0.09~-0.1MPa, and dry for 12 h to obtain HB-PCL.

[0031] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0032] Example 1 A method for preparing a high-temperature resistant crystallizing pipette includes the following steps: S1. Add 0.3 kg of GMA-EMA, 0.15 kg of carbodiimide, 0.06 kg of antioxidant, and 0.15 kg of acylhydrazine nucleating agent to a high-speed mixer and mix at 60°C and 400 r / min for 8 min to obtain processing aids for later use. S2. Add 10 kg of PLLA, 1 kg of PDLA, 1 kg of PBS, 2 kg of talc and 0.2 kg of processing aid to a high-speed mixer. Premix at 80°C and 300 r / min for 5 min, then raise the temperature to 165°C and increase the speed to 250 r / min for 12 min to obtain a homogeneous mixture. S3. Add the mixture to a twin-screw extruder for plasticizing and extruding. Set the temperature as follows: front section of barrel 170℃, middle section of barrel 185℃, rear section of barrel 190℃, die head 195℃, and die head 200℃. The screw speed is 80 r / min. Extrude through the annular die to form a continuous hollow tube blank, with an extrusion speed of 8 m / min. S4. Immediately send the hollow tube blank into the cooling water tank for rapid cooling and shaping, where the cooling water temperature is 25℃ and the residence time is 30s; after shaping, it is pulled to the cutting equipment by the traction machine at a traction speed of 8m / min, and cut into a fixed length of 20cm to obtain the preliminary straw. S5. Place the initial straw into a hot air circulating annealing furnace, heat it to 90°C at a heating rate of 5°C / min, and hold it at that temperature for 1.5 hours for annealing and crystallization; then cool it to room temperature at a cooling rate of 3°C / min to obtain a high-temperature resistant crystallizing straw.

[0033] Example 2-3 Examples 2-3 are based on the preparation method of Example 1, but the dosage of each component of the high-temperature resistant crystallizing pipette is adjusted, as shown in Table 1.

[0034] Comparative Examples 1-3 Comparative Examples 1-2 are based on the preparation method of Example 1, but the amounts of each component of the high-temperature resistant crystallizing pipette are adjusted, as shown in Table 1.

[0035] Comparative Example 3 was prepared using the same method as in Example 1, but without adding GMA-EMA to the processing aids, while keeping all other conditions unchanged.

[0036] The high-temperature resistant crystallizing pipettes prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests, and the test results are shown in Table 1: (1) Impact strength The impact strength of the sample was tested according to the ATSM D6110 test standard; (2) Crystallinity The crystallinity of the sample was tested using a DSC instrument (Netzsch DSC 204, Germany) under a nitrogen atmosphere. The temperature was increased from 20°C to 180°C at a rate of 10°C / min, and the enthalpy curve of the temperature increase was recorded. The crystallinity (Xc) of polylactic acid was calculated using the DSC method. Xc=(△Hm-△Hc) / △Hm0×100%; Where △Hm represents the enthalpy of melting of the pipette sample; △Hc represents the enthalpy of cold crystallization of the pipette sample; △Hm0 represents the melting enthalpy (theoretical enthalpy, equal to 96.30 J / g) of fully crystalline polylactic acid.

[0037] (3) Load heat distortion temperature Test the load heat distortion temperature of the sample according to GB / T 1634-1979.

[0038] Table 1. Raw material list and performance test table for Examples 1-3 and Comparative Examples 1-3

[0039] Referring to Table 1, a comparison of Examples 1-3 and Comparative Examples 1-3 shows that the high-temperature resistant crystallizing pipettes of Examples 1-3 all outperform those of Comparative Examples 1-3. This is because Comparative Example 1 lacks PDLA, making it impossible to form stereocomposite crystals, and it relies solely on PLLA for crystallization, resulting in a significant reduction in crystallinity. Comparative Example 2 lacks PBS, making it difficult to compensate for the brittleness defects of PLLA, leading to a significant decrease in impact strength. At the same time, the optimization effect of PBS on the crystal structure is missing, resulting in a significant decrease in the crystallinity of the pipette. Comparative Example 3 lacks GMA-EMA, making it difficult to form stable chemical bonds and physical entanglements at the multiphase interface, reducing system compatibility, hindering the crystallization process, and resulting in weak bonding between phases, making it prone to phase separation under impact, and significantly reducing impact strength.

[0040] Examples 4-5 Example 4 is based on the preparation method of Example 1, except that GMA-EMA is replaced with an equal amount of GMA-EBA, and all other conditions remain unchanged.

[0041] Example 5 is based on the preparation method of Example 1, but GMA-EMA is replaced in equal amounts with a mixture of GMA-EMA and GMA-EBA, wherein the mass ratio of GMA-EMA to GMA-EBA is 1:1, and the other conditions remain unchanged.

[0042] The high-temperature resistant crystallizing pipettes prepared in Examples 4-5 were subjected to the above performance testing tests, and the test results are shown in Table 2.

[0043] Table 2 Performance test results for Examples 1 and 4-5

[0044] Referring to Table 2, comparing Example 1 and Examples 4-5, it can be seen that the impact strength of the high-temperature crystallization pipettes in Examples 1 and 4-5 remains at a relatively good level, indicating that the use of GMA-EMA and GMA-EBA can effectively improve the compatibility between the components in the raw materials.

[0045] Example 6 Example 6 is based on the preparation method of Example 1, except that carbodiimide is replaced with polymeric carbodiimide in equal amounts, while the other conditions remain unchanged.

[0046] The high-temperature resistant crystallizing pipettes prepared in Examples 1 and 6 were subjected to performance testing. The test results are shown in Table 3. Durability: The sample was immersed in deionized water at 60℃ for 4 hours. The impact strength of the sample after immersion was tested according to the ATSM D6110 test standard, and the impact strength retention rate was calculated. Retention rate = Impact strength after immersion / Initial impact strength × 100%.

[0047] Table 3 Performance test results for Examples 1 and 6

[0048] Referring to Table 3, a comparison of Examples 1 and 6 shows that the high-temperature resistant crystallizing pipette of Example 6 exhibits superior durability, high-temperature resistance, and mechanical properties compared to Example 1. This is because the polymeric carbodiimide exhibits better dispersion in the system, and the flexibility of its molecular chains allows for physical entanglement with the high molecular weight backbone of GMA-EMA, enhancing the interphase interface bonding force, improving system compatibility and crystallization stability, and slightly increasing the crystallinity of the stereocomposite crystal, thereby improving impact strength and load heat distortion temperature. Furthermore, the polymeric carbodiimide can continuously react with the terminal carboxyl groups throughout the entire lifecycle of the material processing and immersion use, blocking the hydrolysis autocatalytic cycle. Simultaneously, its physical entanglement with the GMA graft enhances interfacial stability, reduces phase separation caused by hydrolysis, and thus improves the impact strength retention rate.

[0049] Examples 7-8 Example 7 is based on the preparation method of Example 1, except that the acylhydrazine nucleating agent is replaced by an organophosphate nucleating agent in equal amounts, while the other conditions remain unchanged.

[0050] Example 8 is based on the preparation method of Example 1, but the acyl hydrazine nucleating agent is replaced by an equal amount of a mixture of acyl hydrazine nucleating agent and organophosphate nucleating agent, wherein the mass ratio of acyl hydrazine nucleating agent to organophosphate nucleating agent is 1:1, and the other conditions remain unchanged.

[0051] The high-temperature resistant crystallizing pipettes prepared in Examples 7-8 were subjected to the above performance testing tests, and the test results are shown in Table 4.

[0052] Table 4 Performance test results for Examples 1 and 7-8

[0053] Referring to Table 4, a comparison of Examples 1 and 7-8 shows that the crystallinity, durability, and high-temperature resistance of the high-temperature resistant crystallizing pipettes of Examples 1 and 7-8 are all maintained at a relatively good level, indicating that both acylhydrazine nucleating agents and organophosphate nucleating agents can efficiently provide crystal nucleation sites.

[0054] Examples 9-10 Example 9 is based on the preparation method of Example 1, except that talc powder is replaced with mica in equal amounts, while the other conditions remain unchanged.

[0055] Example 10 is based on the preparation method of Example 1, except that talc powder is replaced with hydrotalcite in equal amounts, and all other conditions remain unchanged.

[0056] The high-temperature resistant crystallizing pipettes prepared in Examples 9-10 were subjected to the above performance testing tests, and the test results are shown in Table 5.

[0057] Table 5 Performance test results for Examples 1 and 9-10

[0058] Referring to Table 5, a comparison of Examples 1 and 9-10 shows that the crystallinity, durability, and high-temperature resistance of the high-temperature resistant crystallizing straws of Examples 1 and 9-10 are all at a relatively good level. This indicates that the use of talc, mica, and hydrotalcite as fillers can effectively accelerate the crystallization of PLLA and play a barrier role through their layered structure.

[0059] Examples 11-13 In Example 11, based on the preparation method of Example 1, 0.25 kg of E-PCL was added together with PLLA, PDLA, PBS, talc and processing aids into a high-speed mixer for mixing, while the other conditions remained unchanged.

[0060] Example 12 is based on the preparation method of Example 11, except that E-PCL is replaced with HB-PCL in equal amounts, while the other conditions remain unchanged.

[0061] Example 13 is based on the preparation method of Example 11, but E-PCL is replaced by an equal amount of a mixture of E-PCL and HB-PCL, wherein the mass ratio of E-PCL to HB-PCL is 7.5:2.5, and the other conditions remain unchanged.

[0062] The high-temperature resistant crystallizing pipettes prepared in Examples 11-13 were subjected to the above performance testing tests, and the test results are shown in Table 6.

[0063] Table 6 Performance test results for Examples 1 and 11-13

[0064] Referring to Table 6, a comparison of Examples 1 and 11-13 shows that the impact strength, durability, and high-temperature resistance of the high-temperature resistant crystallizing straws of Examples 11-13 remain at a superior level. This indicates that the addition of E-PCL and / or HB-PCL can simultaneously improve the straw's durability and high-temperature resistance while enhancing its toughness. This is because E-PCL and / or HB-PCL can form uniformly dispersed flexible micro-regions in the matrix, effectively improving the straw's toughness; they can also anchor fillers and processing aids in the matrix and enhance the straw's durability through their strong interfacial bonding with the matrix.

[0065] Examples 14-17 Examples 14-17 are based on the preparation method of Example 13, with the mass ratio of E-PCL and HB-PCL kept constant, but the mass ratio of E-PCL and HB-PCL is adjusted as shown in Table 7.

[0066] The high-temperature resistant crystallizing pipettes prepared in Examples 14-17 were subjected to the above performance tests, and the test results are shown in Table 7.

[0067] Table 7. Mass ratio and performance test results of E-PCL and HB-PCL in Examples 13-17

[0068] Referring to Table 7, and comparing Examples 13-17, it can be seen that when the mass ratio of E-PCL to HB-PCL is (7-8):(3-2), especially when the mass ratio of E-PCL to HB-PCL is 7.5:2.5, the impact strength, crystallinity, and load heat distortion temperature of the high-temperature crystallizing straw reach a better level. This is because E-PCL forms a continuous flexible channel, and HB-PCL acts as a node of the flexible network. The two are fully entangled with each other, thereby constructing a uniform and stable three-dimensional flexible network, absorbing impact energy, quickly dispersing concentrated stress, and improving the impact resistance of the straw.

[0069] In addition, E-PCL-assisted nucleating agent directionally induces the formation of stereocomposite crystals, while HB-PCL restricts the excessive movement of matrix molecular chains, providing a stable environment for the growth of stereocomposite crystals. The synergistic effect of the two increases the crystallinity of the system, thereby increasing the heat distortion temperature of the pipette under load.

[0070] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high-temperature resistant crystallization straw, characterized in that, It includes the following components in parts by weight: 100 parts PLLA, 5-15 parts PDLA, 5-15 parts PBS, 1-35 parts filler, and 0.1-4 parts processing aids; The processing aids include GMA grafts, hydrolysis-resistant agents, antioxidants, and nucleating agents; The GMA graft includes at least one of GMA-EMA and GMA-EBA.

2. The high-temperature resistant crystallizing straw according to claim 1, characterized in that: The hydrolysis-resistant agent is carbodiimide.

3. The high-temperature resistant crystallizing straw according to claim 2, characterized in that: The hydrolysis-resistant agent is a polymeric carbodiimide.

4. The high-temperature resistant crystallizing straw according to claim 1, characterized in that: The nucleating agent includes at least one of acylhydrazine nucleating agents and organophosphate nucleating agents.

5. The high-temperature resistant crystallizing pipette according to claim 1, characterized in that: The filler includes at least one of talc, mica, and hydrotalcite.

6. The high-temperature resistant crystallizing straw according to claim 1, characterized in that: It also includes toughening agents, which include at least one of E-PCL and HB-PCL.

7. The high-temperature resistant crystallizing straw according to claim 6, characterized in that: The toughening agents include E-PCL and HB-PCL.

8. The high-temperature resistant crystallizing pipette according to claim 7, characterized in that: The mass ratio of E-PCL to HB-PCL is (7-8):(3-2).

9. The method for preparing the high-temperature resistant crystallizing pipette according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Mix the formulated amounts of PLLA, PDLA, PBS, fillers, and processing aids to obtain a mixture; S2. The mixture is sequentially extruded, cooled and cut, and annealed to obtain the high-temperature resistant crystallizing straw.

10. The method for preparing the high-temperature resistant crystallizing pipette according to claim 9, characterized in that: The toughening agent is added to S1 along with PLLA, PDLA, PBS, filler, and processing aids for mixing.

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