PHA environmentally friendly composite wire reinforced by basalt fiber and its preparation method

Abstract

The invention relates to a preparation method of an environmentally friendly PHA composite wire reinforced with basalt fiber, which specifically comprises the following steps: S1: modifying basalt fiber; S2: modifying PHA; S3: weighing the modified PHA, modified basalt fiber, a nucleating agent, a plasticizer, and an antioxidant according to a certain proportion, mixing them in a high-speed mixer, stirring them uniformly, adding the obtained mixture into a twin-screw extruder, and extruding and granulating them at an extrusion temperature of 170-270°C; S4: drawing the obtained pellets into a single-screw wire drawing machine, at a screw speed of 60-85rpm, starting from 15rpm during feeding and gradually increasing to a set speed, and at an extrusion temperature of 190-260°C. The basalt fiber is used to modify the degradable material PHA to prepare a high-performance composite wire. Simultaneously, during the preparation process, the basalt fiber and the PHA raw material are modified separately, and the interface bonding between the basalt fiber and the PHA is improved by using a dual-modification mode, thereby improving the mechanical properties, toughness, and heat resistance of the 3D printing environmentally friendly wire.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of environmentally friendly composite wires, and in particular relates to a basalt fiber-reinforced PHA environmentally friendly composite wire and a preparation method thereof. Background Art

[0002] Polyhydroxyalkanoate (PHA) is a typical biodegradable polyester produced directly by microorganisms. It can be degraded into water and carbon dioxide in the environment. It has also attracted widespread attention for its thermoplastic processability, biocompatibility, and biodegradability, making it an environmentally friendly material. Currently, PHA materials can be used in hydrosols, fibers, packaging, plastic products, medical implants, stents, surgical sutures, and controlled drug release carriers.

[0003] However, PHA also has some disadvantages, such as a narrow processing window and difficulty in molding, and the molding time is generally long; most of them are easily hydrolyzed, the crystallization rate is very slow, and the thermal stability is poor; the toughness is very low, and the mechanical performance advantages are not obvious, etc. These have limited the application range of PHA polymer materials. The main production method of PHA filaments currently on the market is direct hot melt drawing, or by adding certain functional fillers to blend and melt drawing to prepare 3D printing filaments, which have poor mechanical properties, poor toughness, and poor heat resistance.

[0004] Basalt fiber (BF) is made from natural volcanic extrusive rock. Crushed and melted in a furnace at 1450-1500°C, it is then drawn through a platinum-rhodium alloy sieve. As a green and environmentally friendly natural fiber, BF, unlike glass fiber, does not release any toxic chemicals during production. It is completely natural and environmentally friendly, has a higher recycling rate than carbon fiber and glass fiber, and does not pollute the environment. BF exhibits excellent physical and chemical properties, including mechanical strength and chemical resistance, excellent thermal and acoustic insulation, and excellent adhesion to metals, thermosetting resins, and thermoplastic resins. While basalt fiber offers excellent performance and is inexpensive, its surface is chemically inert and very smooth, resulting in poor interfacial compatibility and adhesion with matrices such as resins, limiting its application in composite materials. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a method for preparing an environmentally friendly PHA composite wire reinforced with basalt fiber. During the preparation process, the basalt fiber and PHA raw materials are modified separately, and a dual modification mode is used to improve the interfacial bonding between the basalt fiber and PHA, thereby preparing a high-performance 3D printing environmentally friendly wire.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] Environmentally friendly PHA composite wire reinforced with basalt fiber, prepared by melt blending with chopped basalt fiber as reinforcement and PHA resin as matrix, with tensile strength of 0-185MPa, flexural strength of 0-143MPa, and impact strength of 0-119KJ / m 2 , heat deformation temperature 0-180℃.

[0008] The preparation method of environmentally friendly PHA composite wire reinforced with basalt fiber is as follows:

[0009] S1: Basalt fiber modification: Basalt fiber (BF) was cleaned by soaking in acetone, then ultrasonically cleaned with distilled water. Then, distilled water was replaced with silane coupling agent and ultrasonically mixed. The mass fraction ratio of basalt fiber to silane coupling agent was 90%-99.9%: 0.1%-10%. The BF was then dried in an oven at 80-120°C for 24-72 hours.

[0010] S2: PHA modification: PHA, EHTPB (epoxidized hydroxy-terminated polybutadiene), and DCP (dicumyl peroxide) are mixed in a high-speed mixer. The polyhydroxyalkanoate (PHA) is poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB), with a melt flow rate of 8-15 g / 10 min. The pre-mixing temperature of the mixer is 170-210°C. The mass fraction ratio of PHA resin, EHTPB, and DCP is 80%-98.7%: 1-30%: 0.3-3.5%. The epoxy value of EHTPB is 1.5-1.7 mmmol / g and the molecular weight is 3800-5500. The mixture is then added to a twin-screw extruder and melt-extruded into pellets at a temperature of 180-250°C.

[0011] S3: The modified PHA, modified basalt fiber, nucleating agent, plasticizer, and antioxidant are weighed according to the mass fraction of modified PHA resin, modified basalt fiber, nucleating agent, plasticizer, and antioxidant of 20%-90%: 10%-50%: 0.1%-10%: 1%-30%: 0.1%-3%, mixed in a high-speed mixer, stirred evenly, and the obtained mixture was added to a twin-screw extruder. The extrusion granulation temperature was 170-270°C;

[0012] S4: The obtained pellets are drawn into a single-screw wire drawing machine with a screw speed of 60-85 rpm. When adding materials, the speed starts from 15 rpm and gradually increases to the set speed. The extrusion temperature is 190-260 ° C (die head).

[0013] Furthermore, in step S1, the BF is cleaned by immersing in acetone for 0.5-3 hours, the cleaning time by ultrasonic and distilled water is 1-5 hours, and the ultrasonic mixing time of the silane coupling agent is 0.5-4 hours.

[0014] Furthermore, the basalt fiber in step S1 is a short fiber with a fiber diameter of 1-25 μm and a length of 5-12 mm. The silane coupling agent is any one or any combination of KH550, KH560, KH792, and isobutyl triethoxysilane, preferably a composite silane coupling agent composed of KH792 and isobutyl triethoxysilane, with a weight ratio of 2:3.

[0015] Furthermore, the nucleating agent in step S3 is any one of silicon carbide, boron nitride, talc, and silicon dioxide;

[0016] Furthermore, the plasticizer in step S3 is any one or any combination of polyethylene glycol, polypropylene glycol, polydiethylene glycol adipate, triethyl citrate, and acetyl tributyl citrate, and is more preferably a composite plasticizer composed of polypropylene glycol and triethyl citrate, with a weight ratio of 5:2.

[0017] Furthermore, the antioxidant in step S3 is any one or any combination of antioxidant 1010, antioxidant 168, antioxidant DLTP, and antioxidant 1076.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) Basalt fiber is introduced into PHA material for modification to improve the heat resistance, mechanical properties and toughness of PHA, and prepare high-performance and environmentally friendly 3D printing PHA composite wire;

[0020] (2) The bonding degree between basalt fiber and PHA matrix was increased through a dual modification mode. PHA was modified with epoxidized hydroxyl-terminated polybutadiene (EHTPB) and basalt fiber was modified with a silane coupling agent, respectively giving new reactive groups to PHA and basalt fiber. Furthermore, through the mutual reaction of the surface groups between the two, the interfacial bonding strength between BF and PHA was effectively improved, and the mechanical properties, toughness and heat resistance of the composite material were enhanced.

[0021] (3) Use environmentally friendly materials polyhydroxyalkanoate and basalt fiber to prepare green and environmentally friendly composite wires to avoid environmental pollution. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to specific embodiments.

[0023] Example 1

[0024] The preparation method of environmentally friendly PHA composite wire reinforced with basalt fiber is as follows:

[0025] S1: Basalt fiber modification: The basalt fiber is short fiber with a fiber diameter of 10 μm. The basalt fiber is soaked and cleaned with acetone, then ultrasonically cleaned with distilled water. Then, the distilled water is replaced with a silane coupling agent and ultrasonically mixed (the content of basalt fiber and silane coupling agent is 98.5% and 1.5%, respectively). The acetone soaking and cleaning time is 1 hour, the ultrasonic and distilled water cleaning time is 2 hours, and the ultrasonic mixing time of the silane coupling agent is 0.5 hours. The silane coupling agent is KH550. The fiber is then placed in an oven and dried for 48 hours at a temperature of 100°C.

[0026] S2: PHA (P34HB) modification: PHA, EHTPB, and DCP (PHA, EHTPB, and DCP contents are 96%, 1%, and 3%, respectively) are pre-mixed in a high-speed mixer. PHA is poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) with a melt flow rate of 8-15 g / 10 min. EHTPB has an epoxy value of 1.5-1.7 mmol / g and a molecular weight of 3800-5500. The mixture is then extruded and pelletized. The pre-mixing temperature of PHA, EHTPB, and DCP in the high-speed mixer is 180°C, and the extrusion and pelletization temperature is 210°C.

[0027] S3: The modified PHA, modified basalt fiber, nucleating agent, plasticizer, and antioxidant are weighed in the following ratios: modified PHA resin: 60%; modified basalt fiber: 33%; nucleating agent: 3%; plasticizer: 3%; and antioxidant: 1%. The nucleating agent is silicon carbide, the plasticizer is acetyl tributyl citrate, and the antioxidant is a 3:1 mixture of 1076 and 168. The mixture is mixed in a high-speed mixer and stirred evenly. The resulting mixture is added to a twin-screw extruder at an extrusion temperature of 230°C for melt extrusion and granulation.

[0028] S4: The obtained pellets were drawn into a single-screw wire drawing machine with a screw speed of 75 rpm. When adding materials, the speed started from 15 rpm and gradually increased to the set speed. The extrusion temperature was 220°C (die head).

[0029] The obtained printed wire has a tensile strength of 129.1 MPa, a flexural strength of 113.2 MPa, and an impact strength of 79.1 KJ / m 2 , heat deformation temperature 146℃.

[0030] Comparative Example 1: Commercially available PHA wire, except that no basalt fiber was added.

[0031] Example 2

[0032] The preparation method of environmentally friendly PHA composite wire reinforced with basalt fiber is as follows:

[0033] S1: Basalt fiber modification: The basalt fiber is short fiber with a fiber diameter of 5 μm. The basalt fiber is cleaned by soaking in acetone, then using ultrasound and distilled water for cleaning. Then, the distilled water is replaced with a silane coupling agent and ultrasonically mixed (the basalt fiber and silane coupling agent contents are 97% and 3%, respectively). The acetone soaking and cleaning time is 2.5 hours, the ultrasound and distilled water cleaning time is 1 hour, and the silane coupling agent ultrasonic mixing time is 3.5 hours. The silane coupling agent is a composite silane coupling agent composed of KH792 and isobutyltriethoxysilane in a weight ratio of 2:3. The fiber is then placed in an oven and dried for 65 hours at 90°C.

[0034] S2: PHA (P34HB) modification: PHA, EHTPB, and DCP (PHA, EHTPB, and DCP contents are 87.5%, 10%, and 2.5%, respectively) are pre-mixed in a high-speed mixer. PHA is poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) with a melt flow rate of 8-15 g / 10 min. EHTPB has an epoxy value of 1.5-1.7 mmol / g and a molecular weight of 3800-5500. The mixture is then extruded and granulated. The pre-mixing temperature of PHA, EHTPB, and DCP in the high-speed mixer is 200°C, and the extrusion granulation temperature is 240°C.

[0035] S3: The modified PHA, modified basalt fiber, nucleating agent, plasticizer, and antioxidant are weighed in the following ratios: modified PHA resin: 53%; modified basalt fiber: 37%; nucleating agent: 8%; plasticizer: 1.5%; and antioxidant: 0.5%. The nucleating agent is silicon dioxide, the plasticizer is polydiethylene glycol adipate, and the antioxidant is 1010. The mixture is mixed in a high-speed mixer and stirred evenly. The resulting mixture is added to a twin-screw extruder at an extrusion temperature of 250°C for extrusion granulation.

[0036] S4: The obtained pellets were drawn into a single-screw wire drawing machine with a screw speed of 70 rpm. When adding the material, the speed started from 15 rpm and gradually increased to the set speed. The extrusion temperature was 230°C (die head).

[0037] The obtained printed wire has a tensile strength of 130.3 MPa, a bending strength of 119.7 MPa, and an impact strength of 92.1 KJ / m 2 , heat deformation temperature 149℃.

[0038] Comparative Example 2: A printing wire was prepared according to the method of Example 2, except that the basalt fiber was not modified.

[0039] Example 3

[0040] The preparation method of environmentally friendly PHA composite wire reinforced with basalt fiber is as follows:

[0041] S1: Basalt fiber modification: The basalt fiber is short fiber with a fiber diameter of 20 μm. The basalt fiber is soaked and cleaned with acetone, then ultrasonically cleaned with distilled water. Then, the distilled water is replaced with a silane coupling agent and ultrasonically mixed (the basalt fiber and silane coupling agent contents are 94.5% and 5.5%, respectively). The acetone soaking and cleaning time is 2 h, the ultrasonic and distilled water cleaning time is 3.5 h, and the ultrasonic mixing time of the silane coupling agent is 2.5 h. The silane coupling agent is KH560. The fiber is then placed in an oven and dried for 30 h at a temperature of 110°C.

[0042] S2: PHA (P34HB) modification: PHA, EHTPB, and DCP (PHA, EHTPB, and DCP contents are 81.5%, 16.5%, and 2%, respectively) are pre-mixed in a high-speed mixer. PHA is poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) with a melt flow rate of 8-15 g / 10 min. EHTPB has an epoxy value of 1.5-1.7 mmol / g and a molecular weight of 3800-5500. The mixture is then extruded and pelletized. The pre-mixing temperature of PHA, EHTPB, and DCP in the high-speed mixer is 190°C, and the extrusion and pelletization temperature is 220°C.

[0043] S3: The modified PHA, modified basalt fiber, nucleating agent, plasticizer, and antioxidant are weighed in the following ratios: modified PHA resin: 50%; modified basalt fiber: 48%; nucleating agent: 0.5%; plasticizer: 1%; and antioxidant: 0.5%. The nucleating agent is boron nitride, the plasticizer is a composite plasticizer composed of polypropylene glycol and triethyl citrate, with a weight ratio of 5:2, and the antioxidant is DLTP. The mixture is mixed in a high-speed mixer and stirred evenly. The resulting mixture is added to a twin-screw extruder at an extrusion temperature of 265°C for extrusion granulation.

[0044] S4: The obtained pellets were drawn into a single-screw wire drawing machine with a screw speed of 60 rpm. When adding the material, the speed started from 15 rpm and gradually increased to the set speed. The extrusion temperature was 240°C (die head).

[0045] The obtained printed wire has a tensile strength of 157.5 MPa, a bending strength of 122.4 MPa, and an impact strength of 88.3 KJ / m 2 , heat deformation temperature 161℃.

[0046] Comparative Example 3: A printing filament was prepared according to the method of Example 3, except that the PHA was not modified.

[0047] The mechanical properties of the printing wires (1.75 mm in diameter) prepared in the above examples and comparative examples were tested. The specific results are shown in Table 1.

[0048]

[0049] Table 1

[0050] Table 1 shows that the printing wire prepared in the above embodiment has high strength, good mechanical properties, and significantly improved heat resistance. The test results of the above embodiment show that the basalt fiber / PHA environmentally friendly composite wire provided by the present invention not only has the characteristics of high strength, good toughness, and good heat resistance, but also uses natural green material basalt fiber and biodegradable resin PHA (P34HB) as raw materials, and has the characteristics of being pollution-free and highly environmentally friendly.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an environmentally friendly PHA composite wire reinforced with basalt fiber, wherein the composite wire is prepared by melt blending with chopped basalt fiber as reinforcement and PHA resin as matrix, characterized in that: The specific steps are as follows: S1: Basalt fiber modification: The basalt fiber was soaked and cleaned with acetone, then ultrasonically cleaned with distilled water. Then, the distilled water was replaced with silane coupling agent and ultrasonically mixed. The mass fraction ratio of basalt fiber to silane coupling agent was 90%-99.9%: 0.1%-10%. The fiber was then dried in an oven at 80-120°C for 24-72 hours. S2: PHA modification: PHA, EHTPB, and DCP were mixed in a high-speed mixer. PHA was poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB), with a melt flow rate of 8-15 g / 10 min. The pre-mixing temperature of the mixer was 170-210°C. The mass fraction ratio of PHA resin, EHTPB, and DCP was 80%-98.7%: 1-30%: 0.3-3.5%. The epoxy value of EHTPB was 1.5-1.7 mmmol / g, and the molecular weight was 3800-5500. The mixture was then added to a twin-screw extruder and melt-extruded into pellets at a temperature of 180-250°C. S3: The modified PHA, modified basalt fiber, nucleating agent, plasticizer, and antioxidant are weighed according to the mass fraction of modified PHA resin, modified basalt fiber, nucleating agent, plasticizer, and antioxidant of 20%-90%: 10%-50%: 0.1%-10%: 1%-30%: 0.1%-3%, mixed in a high-speed mixer, stirred evenly, and the obtained mixture was added to a twin-screw extruder. The extrusion granulation temperature was 170-270°C; S4: The obtained pellets are drawn into a single-screw wire drawing machine with a screw speed of 60-85 rpm. When adding materials, the speed starts from 15 rpm and gradually increases to the set speed. The extrusion temperature is 190-260 ° C. The obtained environmentally friendly PHA composite wire has a tensile strength of 0-185 MPa, a flexural strength of 0-143 MPa, and an impact strength of 0-119 KJ / m 2 , heat deformation temperature 0-180℃.

2. The method for preparing an environmentally friendly PHA composite wire reinforced with basalt fiber according to claim 1, characterized in that: In step S1, the BF is cleaned by immersing in acetone for 0.5-3 hours, cleaned by ultrasonic and distilled water for 1-5 hours, and ultrasonically mixed with the silane coupling agent for 0.5-4 hours.

3. The method for preparing an environmentally friendly PHA composite wire reinforced with basalt fiber according to claim 2, characterized in that: The basalt fibers in step S1 are short fibers with a fiber diameter of 1-25 μm and a length of 5-12 mm; the silane coupling agent is any one of KH550, KH560, KH792, and isobutyl triethoxysilane, or any combination thereof.

4. The method for preparing an environmentally friendly PHA composite wire reinforced with basalt fiber according to claim 3, characterized in that: The silane coupling agent is a composite silane coupling agent composed of KH792 and isobutyltriethoxysilane, with a weight ratio of 2:

3.

5. The method for preparing an environmentally friendly PHA composite wire reinforced with basalt fiber according to claim 3, characterized in that: The nucleating agent in step S3 is any one of silicon carbide, boron nitride, talc, and silicon dioxide.

6. The method for preparing an environmentally friendly PHA composite wire reinforced with basalt fiber according to claim 5, characterized in that: The plasticizer in step S3 is any one or any combination of polyethylene glycol, polypropylene glycol, polydiethylene glycol adipate, triethyl citrate, and acetyl tributyl citrate, and the antioxidant is any one or any combination of antioxidant 1010, antioxidant 168, antioxidant DLTP, and antioxidant 1076.

7. The method for preparing an environmentally friendly PHA composite wire reinforced with basalt fiber according to claim 6, characterized in that: The plasticizer is a composite plasticizer composed of polypropylene glycol and triethyl citrate, with a weight ratio of 5:2.

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