Glass fiber reinforced polyethylene composite material and preparation method thereof

Abstract

The invention relates to a glass fiber reinforced polyethylene composite material and a preparation method thereof. The formula of the composite material comprises the following raw material components in parts by weight: 65-89.75 parts of polyethylene, 10-30 parts of glass fiber and 0.25-5 parts of a macromolecular reactive compatibilizer. Compared with the prior art, the invention aims to greatly reduce the use amount (as low as 0.25%) of the compatibilizer in the polyethylene / glass fiber composite material and obviously improve the strength and toughness of the composite material at the same time, thereby opening up a new way for efficiently obtaining the glass fiber reinforced polyethylene composite material with excellent comprehensive mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of polymer material preparation technology, and relates to a glass fiber reinforced polyethylene composite material and its preparation method. Background Technology

[0002] High-density polyethylene (HDPE) is an important thermoplastic resin with advantages such as good stability, easy molding and processing, and low cost, making it widely used in containers, pipes, and profiles. Currently, an important research area for HDPE is the preparation of high-performance glass fiber reinforced polyethylene composites through blending with glass fibers. This significantly improves its mechanical strength and expands its application areas (such as for the preparation of reinforced thermoplastic composite pipes). However, due to the poor compatibility between polar glass fibers and non-polar polyethylene, the effective transfer of applied stress between the glass fibers and the polyethylene matrix cannot be guaranteed, resulting in unsatisfactory mechanical properties of the composite material. Therefore, it is necessary to add compatibilizers (or compatibilizers) to improve the compatibility of the blend and thus enhance the mechanical properties of polyethylene / glass fiber composites.

[0003] However, currently, a relatively large amount of compatibilizer is required to achieve a good modification effect. For example, in the glass fiber reinforced polyethylene composite materials disclosed in CN113462054A and CN111040282A, the mass percentage of compatibilizer added all exceed 5%.

[0004] Adding excessive compatibilizers to polyethylene / glass fiber composites not only increases costs but may also adversely affect their mechanical properties (Plastics Technology, 2016, 44(12): 32-36). Furthermore, for polyolefin / glass fiber composites, there is a phenomenon where strength (tensile strength) increases while toughness (impact strength) decreases (e.g., Materials 2013, 6, 4122-4138; Synthetic Resins and Plastics, 2022, 39(4), 29-34). Therefore, how to significantly reduce the amount of compatibilizer while simultaneously improving the strength and toughness of polyethylene / glass fiber composites is a pressing technical problem that needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a glass fiber reinforced polyethylene composite material and its preparation method, which requires only the addition of a small amount of polymeric reactive compatibilizer to ensure good molecular-level bonding between the polyethylene matrix and glass fibers, resulting in a composite material with both high strength and high toughness.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] In one aspect, the present invention provides a glass fiber reinforced polyethylene composite material, comprising the following raw material components in parts by weight: 65-89.75 parts of polyethylene, 10-30 parts of glass fiber (GF), and 0.25-5 parts of a polymeric reactive compatibilizer. Preferably, based on 100 parts of each raw material, the amount of polymeric reactive compatibilizer added is 0.25-1 part, more preferably 0.25-0.5 parts.

[0008] Furthermore, the polyethylene is HDPE obtained by copolymerization of ethylene and hexene, with a melt index of 30 g / 10 min (190℃ / 2.16 kg) and a density of 0.953-0.959 g / cm³. 3 The weight-average molecular weight (Mw) is 50,000-60,000 g / mol, and the melting point is 130℃.

[0009] Furthermore, the polymeric reactive compatibilizer is maleic anhydride-grafted high-density polyethylene.

[0010] Furthermore, the glass fiber is a short-cut glass fiber with a diameter of 16-18 μm and a length of 4-6 mm.

[0011] Furthermore, the glass fiber undergoes a surface modification process involving plasma treatment, KH550 silane coupling agent modification, and polypropylene emulsion coating. The glass fiber obtained through this treatment, due to its polypropylene coating, can be uniformly dispersed in the HDPE medium when blended with HDPE. In addition, the high-density amino groups on its surface (introduced through plasma treatment and silane coupling agent modification) are exposed during the blending heating process as the polypropylene coating melts, allowing for a highly reactive reaction with the maleic anhydride groups in the compatibilizer. This significantly improves the adhesion between the glass fiber and HDPE interface, ultimately resulting in a substantial increase in both the strength and toughness of the composite material.

[0012] Furthermore, the surface modification process of the glass fiber includes the following steps:

[0013] (A) Plasma treatment is applied to glass fibers to improve their surface hydroxyl activity;

[0014] (B) Plasma-treated glass fibers are placed in an alcohol / water solution of KH550 silane coupling agent, impregnated, and dried to obtain KH550 pretreated glass fibers.

[0015] (C) The glass fiber pretreated with KH550 is soaked in polypropylene wax emulsion and dried to obtain glass fiber with PP coating, thus completing the surface modification.

[0016] More preferably, in step (A), the plasma treatment process is as follows: the cleaned glass fiber is placed in the plasma reaction chamber and plasma-treated in oxygen at a power of 375W for 240s under the action of a high-frequency electric field.

[0017] In step (B), the pH value of the alcohol / water solution of KH550 silane coupling agent is 4-5, the mass fraction of KH550 silane coupling agent is 4-6%, which can be 5%, and the mass ratio of alcohol to water is 1:4-6, which can be 1:5.

[0018] In step (C), the soaking time is 0.5-1.5 minutes.

[0019] More preferably, in step (C), the polypropylene wax emulsion is prepared by the following process:

[0020] Emulsifier OP is dissolved in deionized water, the pH is adjusted to 8, and then a xylene solution of polypropylene wax is added dropwise under stirring to obtain a polypropylene wax emulsion. The ratio of emulsifier OP to polypropylene wax is 2-4:100, which can be 3:100.

[0021] In another aspect, the present invention provides a method for preparing glass fiber reinforced polyethylene composite material, wherein polyethylene, glass fiber and polymeric reactive compatibilizer are weighed according to the specified ratio, mixed and fed into a twin-screw extruder, and extruded to obtain glass fiber reinforced polyethylene composite material.

[0022] Furthermore, the screw temperature in the twin-screw extruder is 170-185℃, the rotation speed is 120-180 rpm, and the residence time of the material in the screw is 1-2 min.

[0023] Furthermore, the extruded glass fiber reinforced polyethylene composite material can also be put into an injection molding machine for direct injection molding to obtain glass fiber reinforced polyethylene composite injection molding specimens.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) High-density polyethylene has low molecular weight and high melt index (high fluidity), which is beneficial for material mixing in the molten state; the melting point of the compatibilizer 5108 used is almost exactly the same as the melting temperature of DHD5630 HDPE, so they can melt simultaneously when they are blended in a twin-screw extruder to achieve uniform dispersion.

[0026] (2) As a result of the combined effect of multiple factors (including the high melt flow properties of DHD5630, the presence of PP coating on glass fiber surface and aminosilane coupling agent, the same melting temperature of compatibilizer 5108 and DHD5630, and the highly active maleic anhydride reactive groups of compatibilizer 5108), even if a trace amount (0.25%) of compatibilizer 5108 is added to the DHD5630 / GF composite system, the purpose of GF to significantly strengthen and toughen HDPE at the same time can be achieved.

[0027] (3) The polyethylene / glass fiber composite material obtained has both high strength and high toughness. Compared with pure polyethylene and polyethylene / glass fiber composite material without compatibilizer, its mechanical properties (including tensile breaking strength and notched impact strength) are significantly improved, which expands the application range of polyethylene and has important practical significance. Attached Figure Description

[0028] Figure 1 SEM images of the cross sections of each impact specimen are shown, where (a) pure DHD5630; (b) DHD5630 / 20%GF composite sample without compatibilizer 5108; (c) DHD5630 / 20%GF / 0.25%5108; (d) DHD5630 / 20%GF / 0.5%5108; (e) DHD5630 / 20%GF / 3%5108; and (f) DHD5630 / 20%GF / 5%5108.

[0029] Figure 2 The graphs show the mechanical properties of different composite material spline specimens, where... Figure 2 a shows the tensile fracture strength of specimens with different compatibilizer contents when the glass fiber content in the composite material is 20%; Figure 2 b is a notched impact strength diagram of simply supported beams for specimens with different compatibilizer contents when the glass fiber content in the composite material is 20%; Figure 2 c shows the tensile fracture strength of specimens with different compatibilizer contents when the glass fiber content in the composite material is 30%; Figure 2 Figure d shows the notched impact strength of simply supported beams for composite materials with different compatibilizer contents when the glass fiber content is 30%. Please provide an explanation for each figure.

[0030] Figure 3 The diagram shows the mechanical properties of the composite material spline in Comparative Example 1, where... Figure 3 a is the tensile breaking strength diagram of the specimen in DHD5630 / 20% glass fiber composite material without the addition of 0.25% compatibilizer FB9270 or 5108; Figure 3 b is the notched impact strength diagram of a simply supported beam of a specimen in DHD5630 / 20% glass fiber composite material without the addition of 0.25% compatibilizer FB9270 or 5108. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0032] In the following embodiments, the polyethylene used is HDPE obtained by ethylene-hexene copolymerization, which was purchased from Dushanzi Petrochemical Company, DHD5630.

[0033] The reactive polymer compatibilizer is maleic anhydride-grafted high-density polyethylene (HDPE-g-MAH), Polyram Group (Israel Polyram). 5108: Maleic anhydride functional group content is 0.9%, melt index is 3 g / 10 min (190℃ / 2.16 kg), and density is 0.960 g / cm³. 3 The weight-average molecular weight (Mw) is 50,000-60,000 g / mol, and the melting point is 131℃.

[0034] Tensile strength was tested according to national standard GB / T1040.2-2022, and notched impact strength was tested according to national standard GB / T1043.1-2008.

[0035] The glass fiber is pretreated using the following method:

[0036] First, the glass fiber surface was cleaned with hydrogen peroxide / ammonia / deionized water, rinsed with distilled water, and dried at 105℃ for 4 hours. Then, the cleaned glass fiber (short-cut glass fiber, diameter 17.3±0.1μm, length 5mm) was placed in a plasma reaction chamber. Under the action of a high-frequency electric field, plasma was generated to activate the surface of the glass fiber. Then, the plasma-treated glass fiber was placed in a 5wt% KH550 alcohol / water solution (alcohol-to-water mass ratio m / m). The glass fiber pretreated with KH550 was obtained by soaking it in a 1:5 solution (adjusting the pH to 4-5 with acetic acid, then hydrolyzing for 30 minutes) at 80℃ for 8 hours, then removing it and vacuum drying at 120℃ for 1 hour to allow for complete reaction. Finally, the KH550 pretreated glass fiber was soaked in a polypropylene wax emulsion (polypropylene wax, brand name LC1601, dissolved in xylene; emulsifier OP-10 dissolved in deionized water at 50-60℃, adjusting the pH of the solution to 8 with NaOH, adding the xylene solution of polypropylene wax dropwise under stirring, stirring at a high shear rate for 30 minutes to obtain the polypropylene wax emulsion, where the mass ratio of emulsifier to polypropylene wax is 3:100) for 1 minute and then dried to obtain PP-coated glass fiber.

[0037] The experimental conditions for the twin-screw extruder (SHJ-20, Nanjing JENTE Electromechanical Co., Ltd.) are shown in Table 1 below.

[0038] Table 1

[0039]

[0040] The model of the injection molding machine used is (BL-6179-BL, Dongguan Baolun Precision Testing Instruments Co., Ltd.), and the experimental conditions for injection molding are shown in Table 2 below.

[0041] Table 2

[0042]

[0043] Unless otherwise specified, all other raw materials or processing techniques are commercially available materials or conventional processing techniques in the field.

[0044] Example 1:

[0045] The raw material components by weight are: 79.75 parts of ethylene-hexene copolymer HDPE, 20 parts of glass fiber, and 0.25 parts of polymeric reaction compatibilizer PE-g-MAH.

[0046] Ethylene-hexene copolymer HDPE, glass fiber, and a polymeric reactive compatibilizer were fed into a twin-screw extruder for extrusion and then granulated using a pelletizer. The screw temperatures were set at 170 / 180 / 185 / 185 / 175 / 170℃, the screw speed was 150 rpm, and the material residence time in the screw was 1.5 min. After cooling, the extruded material was pelletized and dried in a vacuum oven at 85℃ for 3 h to obtain an HDPE / glass fiber composite material containing 0.25% compatibilizer. Injection molding was then performed to obtain tensile and impact test specimens of the HDPE / glass fiber composite material.

[0047] Mechanical properties were tested on pure HDPE, a composite material without compatibilizer, and the aforementioned composite material. The results were as follows: the tensile breaking strength of pure HDPE was 10.4 ± 0.2 MPa, and the notched impact strength was 3.0 ± 0.4 kJ / m. 2 The tensile breaking strength of HDPE / glass fiber without compatibilizer is 20.6±0.4MPa, and the notched impact strength is 3.9±0.2kJ / m. 2 The tensile breaking strength of the HDPE / glass fiber composite material containing 0.25% compatibilizer is 30.0±1.6MPa, and the notched impact strength is 5.7±0.6kJ / m. 2 .

[0048] Example 2:

[0049] The raw material components by weight are: 79.5 parts of ethylene-hexene copolymer HDPE, 20 parts of glass fiber, and 0.5 parts of polymeric reaction compatibilizer PE-g-MAH.

[0050] Ethylene-hexene copolymer HDPE, glass fiber, and a polymeric reactive compatibilizer were fed into a twin-screw extruder for extrusion and then granulated using a pelletizer. The screw temperatures were set sequentially to 170 / 180 / 185 / 185 / 175 / 170℃, the screw speed was 150 rpm, and the material residence time in the screw was 1.5 min. After cooling, the extruded material was pelletized and dried in a vacuum oven at 85℃ for 3 h to obtain an HDPE / glass fiber composite material containing 0.5% compatibilizer. Injection molding was then performed to obtain tensile and impact test specimens of the HDPE / glass fiber composite material.

[0051] Mechanical properties were tested on pure HDPE, a composite material without compatibilizer, and the aforementioned composite material. The results were as follows: the tensile breaking strength of pure HDPE was 10.4 ± 0.2 MPa, and the notched impact strength was 3.0 kJ / m. 2 The tensile breaking strength of HDPE / glass fiber without compatibilizer is 20.6±0.4MPa, and the notched impact strength is 3.9±0.2kJ / m. 2 The tensile breaking strength of the HDPE / glass fiber composite material containing 0.5% compatibilizer was 29.3±0.7MPa, and the notched impact strength was 5.0±0.4kJ / m. 2 .

[0052] Example 3:

[0053] The raw material components by weight are: 75 parts of ethylene-hexene copolymer HDPE, 20 parts of glass fiber, and 5 parts of polymeric reactive compatibilizer PE-g-MAH.

[0054] Ethylene-hexene copolymer HDPE, glass fiber, and a polymeric reactive compatibilizer were fed into a twin-screw extruder for extrusion and then granulated using a pelletizer. The screw temperatures were set at 170 / 180 / 185 / 185 / 175 / 170℃, the screw speed was 150 rpm, and the material residence time in the screw was 1.5 min. After cooling, the extruded material was pelletized and dried in a vacuum oven at 85℃ for 3 h to obtain an HDPE / glass fiber composite material containing 5% compatibilizer. Injection molding was then performed to obtain tensile and impact test specimens of the HDPE / glass fiber composite material.

[0055] Mechanical properties were tested on pure HDPE, a composite material without compatibilizer, and the aforementioned composite material. The results were as follows: the tensile breaking strength of pure HDPE was 10.4 ± 0.2 MPa, and the notched impact strength was 3.0 kJ / m.2 The tensile breaking strength of HDPE / glass fiber without compatibilizer is 20.6±0.4MPa, and the notched impact strength is 3.9±0.2kJ / m. 2 The tensile strength of the HDPE / glass fiber composite material containing 5% compatibilizer is 29.1±0.8MPa, and the notched impact strength is 5.4±0.3kJ / m. 2 .

[0056] Example 4:

[0057] The raw material components by weight are: 69.75 parts of ethylene-hexene copolymer HDPE, 30 parts of glass fiber, and 0.25 parts of polymeric reactive compatibilizer PE-g-MAH.

[0058] Ethylene-hexene copolymer HDPE, glass fiber, and a polymeric reactive compatibilizer were fed into a twin-screw extruder for extrusion and then granulated using a pelletizer. The screw temperatures were set at 170 / 180 / 185 / 185 / 175 / 170℃, the screw speed was 150 rpm, and the material residence time in the screw was 1.5 min. After cooling, the extruded material was pelletized and dried in a vacuum oven at 85℃ for 3 h to obtain an HDPE / glass fiber composite material containing 0.25% compatibilizer. Injection molding was then performed to obtain tensile and impact test specimens of the HDPE / glass fiber composite material.

[0059] Mechanical properties were tested on pure HDPE, a composite material without compatibilizer, and the aforementioned composite material. The results were as follows: the tensile breaking strength of pure HDPE was 10.4 ± 0.2 MPa, and the notched impact strength was 3.0 ± 0.4 kJ / m. 2 The tensile breaking strength of HDPE / glass fiber without compatibilizer is 20.6±0.4MPa, and the notched impact strength is 4.0±0.2kJ / m. 2 The tensile breaking strength of the HDPE / glass fiber composite containing 0.25% compatibilizer was 28.1±0.7MPa, and the notched impact strength was 6.3±0.3kJ / m. 2 .

[0060] Example 5:

[0061] The raw material components by weight are: 69.5 parts of ethylene-hexene copolymer HDPE, 30 parts of glass fiber, and 0.5 parts of polymeric reaction compatibilizer PE-g-MAH.

[0062] Ethylene-hexene copolymer HDPE, glass fiber, and a polymeric reactive compatibilizer were fed into a twin-screw extruder for extrusion and then granulated using a pelletizer. The screw temperatures were set at 170 / 180 / 185 / 185 / 175 / 170℃, the screw speed was 150 rpm, and the material residence time in the screw was 1.5 min. After cooling, the extruded material was pelletized and dried in a vacuum oven at 85℃ for 3 h to obtain an HDPE / glass fiber composite material containing 0.25% compatibilizer. Injection molding was then performed to obtain tensile and impact test specimens of the HDPE / glass fiber composite material.

[0063] Mechanical properties were tested on pure HDPE, a composite material without compatibilizer, and the aforementioned composite material. The results were as follows: the tensile breaking strength of pure HDPE was 10.4 ± 0.2 MPa, and the notched impact strength was 3.0 ± 0.4 kJ / m. 2 The tensile breaking strength of HDPE / glass fiber without compatibilizer is 20.8±0.3MPa, and the notched impact strength is 4.0±0.2kJ / m. 2 The tensile breaking strength of the HDPE / glass fiber composite material containing 0.5% compatibilizer was 29.2±0.7MPa, and the notched impact strength was 6.6±0.6kJ / m. 2 .

[0064] Example 6:

[0065] The raw material components by weight are: 65 parts of ethylene-hexene copolymer HDPE, 30 parts of glass fiber, and 5 parts of polymeric reactive compatibilizer PE-g-MAH.

[0066] Ethylene-hexene copolymer HDPE, glass fiber, and a polymeric reactive compatibilizer were fed into a twin-screw extruder for extrusion and then granulated using a pelletizer. The screw temperatures were set at 170 / 180 / 185 / 185 / 175 / 170℃, the screw speed was 150 rpm, and the material residence time in the screw was 1.5 min. After cooling, the extruded material was pelletized and dried in a vacuum oven at 85℃ for 3 h to obtain an HDPE / glass fiber composite material containing 0.25% compatibilizer. Injection molding was then performed to obtain tensile and impact test specimens of the HDPE / glass fiber composite material.

[0067] Mechanical properties were tested on pure HDPE, a composite material without compatibilizer, and the aforementioned composite material. The results were as follows: the tensile breaking strength of pure HDPE was 10.4 ± 0.2 MPa, and the notched impact strength was 3.0 ± 0.4 kJ / m. 2 The tensile breaking strength of HDPE / glass fiber without compatibilizer is 20.8±0.3MPa, and the notched impact strength is 4.0±0.2kJ / m.2 The tensile breaking strength of the HDPE / glass fiber composite material containing 5% compatibilizer is 30.8±0.5MPa, and the notched impact strength is 7.6±0.8kJ / m. 2 .

[0068] Figure 1 SEM characterization results of the impacted specimen cross-sections showed that: (1) among all DHD5630 / 20%GF composite samples with added GF ( Figure 1 Both bf and GF can be uniformly dispersed in the HDPE medium. This is likely due to the PP coating on the surface of GF.

[0069] (2) In the cross-section of the DHD5630 / 20%GF composite sample without compatibilizer 5108, there are numerous pores left by GF pull-out, and the GF surface at the interface is smooth. Figure 1 b) indicates that the interfacial adhesion between GF and HDPE is poor when no compatibilizer is added.

[0070] (3) In the cross-section of the DHD5630 / 20%GF composite sample with 0.25% compatibilizer 5108, there was a significant reduction in the pores left by the pull-out GF, and the GF surface in the interface had a significant polymer coating. Figure 1 c) indicates that the interfacial adhesion between GF and DHD5630 HDPE is significantly improved. This result is due to the reaction between the maleic anhydride in the compatibilizer and the amino coupling agent on the surface of GF, which links the PE chains in the compatibilizer to the surface of GF, thereby achieving effective bonding between GF and the DHD5630 HDPE matrix.

[0071] (4) The cross-sectional characteristics of the DHD5630 / 20%GF / 0.5-5%%5108 composite sample with more than 0.25% compatibilizer 5108 are similar to those of the DHD5630 / 20%GF / 0.25%5108 composite sample with 0.25% compatibilizer 5108.

[0072] Figure 2 The results show that: 1) Compared with pure HDPE and DHD5630 / 20% or 30% glass fiber composite specimens without compatibilizer 5108, the tensile breaking strength of the composite specimens with 0.25% compatibilizer 5108 is higher. Figure 2 a, c) and notch impact strength ( Figure 2 b) Both d) showed significant improvement; 2) Increasing the amount of compatibilizer 5108 from 0.25% to 5% had little effect on the tensile fracture strength and notched impact strength of the composite material specimens.

[0073] Comparative Example 1:

[0074] Compared with the DHD5630 / 20% glass fiber / 0.25% compatibilizer prepared in Example 1, the only difference was that the compatibilizer 5108 was replaced with an equal mass of maleic anhydride-grafted polypropylene FB9270.

[0075] Combination Figure 3 It can be seen that, compared with the DHD5630 / 20% glass fiber / 0.25% compatibilizer prepared in Example 1, the tensile strength and notched impact strength of the sample obtained by replacing compatibilizer 5108 with an equal mass of maleic anhydride-grafted polypropylene FB9270 are significantly reduced, indicating that the compatibilizer 5108 used in this invention has significant advantages over the commonly used compatibilizer FB9270.

[0076] Comparative Example 2:

[0077] Compared to the DHD5630 / 20% glass fiber / 0.25% compatibilizer sample prepared in Example 1, the only difference is that the glass fiber surface was not surface-treated. Compared to the DHD5630 / 20% glass fiber (surface-modified) / 0.25% compatibilizer sample prepared in Example 1, the mechanical properties of the resulting composite sample are significantly reduced due to poor system compatibility because of the use of unmodified glass fiber.

[0078] Comparative Example 3:

[0079] Compared with the DHD5630 / 20% glass fiber / 0.25% compatibilizer prepared in Example 1, the glass fiber surface was only subjected to plasma treatment and silane coupling agent modification, but no polypropylene coating was applied.

[0080] Comparative Example 4:

[0081] Compared with the DHD5630 / 20% glass fiber / 0.25% compatibilizer prepared in Example 1, the glass fiber surface was only coated with a polypropylene coating, but no plasma treatment or silane coupling agent modification was performed.

[0082] Compared with the properties of the DHD5630 / 20% glass fiber (surface modified) / 0.25% compatibilizer prepared in Example 1, the glass fibers used in Comparative Examples 3 and 4 that were only plasma-treated and modified with silane coupling agents but not coated with polypropylene, or glass fibers that were not plasma-treated and modified with silane coupling agents but coated with a polypropylene coating, also resulted in a decrease in system compatibility and a decrease in the mechanical properties of the composite material.

[0083] Based on the above samples, it can be seen that this invention, by adding as little as 0.25% of a polymeric reactive compatibilizer to polyethylene / glass fiber composites and employing a simple twin-screw blending extrusion and injection molding method, yields a composite material possessing both high strength and high toughness. Compared to pure polyethylene, the tensile breaking strength and notched impact strength of the polyethylene / glass fiber composite containing 0.25% polymeric reactive compatibilizer are increased by 2.9 times and 2.1 times, respectively; while compared to the polyethylene / glass fiber composite without compatibilizer, both its tensile breaking strength and notched impact strength are increased by 1.5 times. This invention not only reduces sample preparation costs but also prevents adverse effects on mechanical properties caused by excessive compatibilizer addition, thus possessing significant practical value.

[0084] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A glass fiber reinforced polyethylene composite material, characterized in that, The raw material components include the following parts by weight: 65-89.75 parts of polyethylene, 10-30 parts of glass fiber, and 0.25-5 parts of polymeric reactive compatibilizer.

2. The glass fiber reinforced polyethylene composite material according to claim 1, characterized in that, The polyethylene is HDPE obtained by copolymerizing ethylene and hexene, with a melt index of 30 g / 10 min (190℃ / 2.16 kg) and a density of 0.953-0.959 g / cm³. 3 The weight-average molecular weight (Mw) is 50,000-60,000 g / mol.

3. The glass fiber reinforced polyethylene composite material according to claim 1, characterized in that, The polymeric reactive compatibilizer is maleic anhydride-grafted high-density polyethylene.

4. The glass fiber reinforced polyethylene composite material according to claim 1, characterized in that, The glass fiber is a short-cut glass fiber with a diameter of 16-18 μm and a length of 4-6 mm.

5. The glass fiber reinforced polyethylene composite material according to claim 1, characterized in that, The glass fiber also undergoes a surface modification process involving plasma treatment, KH550 silane coupling agent modification, and polypropylene emulsion coating.

6. The glass fiber reinforced polyethylene composite material according to claim 5, characterized in that, The surface modification process of the glass fiber includes the following steps: (A) Plasma treatment is applied to glass fibers to improve their surface hydroxyl activity; (B) Plasma-treated glass fibers are placed in an alcohol / water solution of KH550 silane coupling agent, impregnated, and dried to obtain KH550 pretreated glass fibers. (C) The glass fiber pretreated with KH550 is soaked in polypropylene wax emulsion and dried to obtain glass fiber with PP coating, thus completing the surface modification.

7. The glass fiber reinforced polyethylene composite material according to claim 6, characterized in that, In step (A), the plasma treatment process is as follows: the cleaned glass fiber is placed in the plasma reaction chamber and plasma-treated for 240s at a power of 375W in oxygen under the action of a high-frequency electric field. In step (B), the pH value of the alcohol / water solution of KH550 silane coupling agent is 4-5, the mass fraction of KH550 silane coupling agent is 4-6%, and the mass ratio of alcohol to water is 1:4-6. In step (C), the soaking time is 0.5-1.5 minutes.

8. The glass fiber reinforced polyethylene composite material according to claim 6, characterized in that, In step (C), the polypropylene wax emulsion is prepared through the following process: Emulsifier OP is dissolved in deionized water, the pH is adjusted to 8, and then a xylene solution of polypropylene wax is added dropwise under stirring to obtain a polypropylene wax emulsion. The ratio of the amount of emulsifier OP to the amount of polypropylene wax added is 2-4:

100.

9. The method for preparing the glass fiber reinforced polyethylene composite material according to any one of claims 1-8, characterized in that, Polyethylene, glass fiber, and polymer reactive compatibilizer were weighed and mixed according to the specified ratio, and fed into a twin-screw extruder for extrusion molding to obtain glass fiber reinforced polyethylene composite material.

10. The method for preparing glass fiber reinforced polyethylene composite material according to claim 9, characterized in that, The screw temperature in the twin-screw extruder is 170-185℃, the rotation speed is 120-180 rpm, and the residence time of the material in the screw is 1-2 min.

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