阅读说明：本技术 一种天然植物纤维混杂复合材料及制备方法 (Natural plant fiber hybrid composite material and preparation method thereof ) 是由 王明辉 李志刚 管志平 马品奎 宋家旺 高丹 管晓芳 徐进 于 2019-10-10 设计创作，主要内容包括：本发明涉及一种天然植物纤维混杂复合材料及制备方法,属于轻量化复合材料技术领域。该复合材料包括混杂纤维铺层：是由经纱和纬纱纺织而成的织物,由内到外包括：内芯高强纤维层、中间天然植物纤维层、外层树脂纤维层,外层树脂纤维层采用包芯纺纱工艺实现树脂纤维与天然植物纤维的混纺,中间天然植物纤维层采用包缠纺纱工艺实现天然植物纤维与内芯高强纤维的混纺。制备过程：将树脂薄膜铺层与混杂纤维铺层依次交替层叠,然后将其放入平板硫化机平板模中进行热压成形。本发明具有能耗低、可循环利用、环境友好、价格低、可设计性更加灵活等优势,与传统制备方法相比,具有力学性能更优异、流程更简便,能实现轻量化复合材料大规模产业化应用。(The invention relates to a natural plant fiber hybrid composite material and a preparation method thereof, belonging to the technical field of lightweight composite materials. The composite material comprises a hybrid fiber lay-up: is a fabric woven by warp yarns and weft yarns, and comprises the following components from inside to outside: the fiber comprises an inner core high-strength fiber layer, an intermediate natural plant fiber layer and an outer resin fiber layer, wherein the outer resin fiber layer is blended by resin fibers and natural plant fibers through a core-spun spinning process, and the intermediate natural plant fiber layer is blended by the natural plant fibers and the inner core high-strength fibers through a wrap-spun spinning process. The preparation process comprises the following steps: and (3) alternately laminating the resin film layers and the hybrid fiber layers in sequence, and then putting the resin film layers and the hybrid fiber layers into a flat plate mold of a flat vulcanizing machine for hot press forming. The preparation method has the advantages of low energy consumption, cyclic utilization, environmental friendliness, low price, more flexible designability and the like, has more excellent mechanical properties and simpler and more convenient flow compared with the traditional preparation method, and can realize large-scale industrial application of the lightweight composite material.)

1. A natural plant fiber hybrid composite, comprising: the fiber layer is a fabric woven by warps and wefts, and the warps or the wefts comprise from inside to outside: the composite material plate is prepared by the steps of sequentially and alternately laminating a resin film layer and a hybrid fiber layer in the preparation process of the composite material, and then putting the resin film layer and the hybrid fiber layer into a flat plate mold of a flat vulcanizing machine for hot press forming.

2. The natural plant fiber hybrid composite according to claim 1, wherein the resin in the composite is selected from the group consisting of: polypropylene, polylactic acid, PA6 or PA66, wherein the high-strength fibers of the inner core in the warp yarns or the weft yarns of the composite material are selected from the following components: the natural plant fibers in the warp or weft of the composite material are selected from the following materials: hemp, ramie, jute, flax, kenaf or sisal.

3. The natural plant fiber hybrid composite material according to claim 1 or 2, wherein the inner core high-strength fiber in the warp or weft of the composite material is subjected to surface treatment, and the middle natural plant fiber in the warp or weft of the composite material is subjected to modification treatment by alkali solution.

4. The natural plant fiber hybrid composite material as claimed in any one of claims 3, wherein the outer resin fiber layer in the composite warp or weft adopts a core-spun spinning process to realize blending of resin fibers and natural plant fibers, and the middle natural plant fiber layer in the composite warp or weft adopts an wrap-spun spinning process to realize blending of natural plant fibers and inner core high-strength fibers.

5. The natural plant fiber hybrid composite material according to any one of claims 1 or 2, wherein the mass fraction of the inner core high-strength fibers in the warp or weft of the composite material is 10-25%, and the mass fraction of the middle natural plant fibers is 30-75%.

6. The natural plant fiber hybrid composite material according to any one of claims 1 or 2, wherein the volume fraction of the natural plant fibers in the composite material is 35% to 60%, and the volume fraction of the high-strength fibers is 5% to 15%.

7. The method for preparing the natural plant fiber hybrid composite material as claimed in claim 1, wherein the hybrid fiber layer is woven by plain weave or twill weave.

8. The preparation method of the natural plant fiber hybrid composite material according to any one of claims 1 to 8, comprising the following steps:

1) soaking natural plant fiber in 5-15% NaOH water solution for 10-24 h, and drying at 60-80 deg.C for 8-12 h;

2) carrying out surface treatment on the high-strength fibers, and drying for later use;

3) on a spinning machine, the high-strength fiber filaments obtained in the step 2) are used as an inner core, the natural plant fibers and the resin short fibers obtained in the step 1) are coated outside, twisting is carried out to form warp yarns or weft yarns of the core-spun yarns, and then plain weave or twill weave mixed fiber fabrics are adopted for standby;

4) cleaning and drying the resin master batch, and hot-pressing the resin master batch on a flat vulcanizing machine to form a resin film layer with the thickness of 0.2-0.5mm for later use;

5) covering the upper and lower surfaces of the fabric obtained in the step 3) with two layers of resin film laminates obtained in the step 4), and sequentially and alternately laminating to prepare a laminate;

6) attaching a polytetrafluoroethylene film on a flat plate mold of a flat vulcanizing machine, placing the layering laminated object obtained in the step 5) into the flat plate mold of the flat vulcanizing machine, and molding to form the composite material plate.

9. The method as claimed in claim 8, wherein the thermoforming temperature is about 170 ℃ and 185 ℃ and the pressure is about 2-6 MPa.

Technical Field

The invention relates to a natural plant fiber hybrid composite material and a preparation method thereof, belonging to the technical field of lightweight composite materials.

Background

The fiber reinforced composite material is a key basic material supporting development of lightweight environment-friendly materials, and the light homogeneous high-strength, recycling and environment-friendly composite material is increasingly required in the industries of automobiles, high-speed rails, aviation, ships, building materials and the like, and the traditional synthetic fiber reinforced composite material cannot meet the requirements of social development due to the problems of high energy consumption, environment unfriendliness and the like, so that the development of natural plant fiber reinforced composite materials is more and more emphasized, and the natural plant fiber reinforced composite material has the characteristics of light weight, environmental protection, sound absorption, heat insulation, impact resistance, low cost and the like, but is mainly applied to non-bearing structural members and cannot be used in secondary bearing structures or even bearing structures due to the limitation of mechanical properties.

In order to improve the mechanical property of natural plant fiber reinforced composite materials, various preparation methods of natural plant fiber hybrid composite materials are developed in succession, the mechanical property of the natural plant fiber hybrid composite materials is improved due to the addition of a high-strength second phase, the conventional preparation method of the fiber reinforced composite materials is mainly adopted for the preparation of the natural plant fiber hybrid composite materials at present, but the improvement degree of the mechanical property of the natural plant fiber hybrid composite materials is greatly influenced by the hybrid preparation method, the improvement is very limited, the requirement of large-scale production cannot be met, and the preparation method of the natural plant fiber hybrid composite materials is urgently needed to be developed, so that the large-scale batch production of secondary bearing structural members and even bearing structural members can be realized.

The core-spun yarn generally takes synthetic fiber filament as an inner core, is coated with short fiber and is twisted to form the core-spun yarn, the core filament is distributed in the yarn, the short fiber is distributed and coated on the outer layer of the core filament, the blending of different fibers can be realized, the wrapping spinning yarn is developed by siro spinning, the core-spun yarn is different from the core-spun yarn in that the filament and the short fiber are in a plied yarn structure, the short fiber is not completely coated with the filament, the wrapping spinning yarn and the core-spun yarn can realize the blending of different fibers, the special characteristics of the two fibers are fully exerted and mutually reinforced.

Disclosure of Invention

The invention aims to provide a natural plant fiber hybrid composite material and a preparation method thereof, which solve the problems of poor wettability between reinforced natural plant fibers and a resin matrix interface and poor mechanical property of a formed part, so that the formed part has excellent mechanical property, and the requirement of producing secondary bearing or even bearing structural parts on a large scale at low cost is met.

The natural plant fiber hybrid composite material comprises a hybrid fiber layer and a resin film layer, wherein the hybrid fiber layer is a fabric woven by warp yarns and weft yarns, and the warp yarns or the weft yarns comprise from outside to inside: the inner core high-strength fiber layer, the middle natural plant fiber layer and the outer resin fiber layer; the outer resin fiber layer is arranged on the surface of the middle natural fiber layer; the inner core high-strength fiber layer takes high-strength fibers as main fibers; in the preparation process of the composite material, firstly, two layers of resin film layers are respectively covered on the upper surface and the lower surface of the hybrid fiber layer, the layers are sequentially and alternately laminated to prepare a layer laminated object, and then the layer laminated object is placed into a flat plate mold of a flat vulcanizing machine for hot press forming to prepare the composite material plate.

Further, the natural plant fibers in the composite material are selected from the following materials: hemp, ramie, jute, flax, kenaf, sisal.

Further, the resin in the composite material is selected from: polypropylene, polylactic acid, PA6 and PA 66.

Further, the composite material has a core of high strength fibers selected from the group consisting of: carbon fiber, aramid fiber and basalt.

Further, the inner core high-strength fiber is subjected to surface treatment.

Further, the intermediate natural plant fiber is modified by alkali solution.

Further, the outer resin fiber layer is blended with the natural plant fiber by adopting a core-spun spinning process.

Furthermore, the middle natural plant fiber layer is blended by the natural plant fibers and the inner core high-strength fibers by adopting a wrapping spinning process.

Furthermore, in the warp (weft), the mass fraction of the high-strength fibers of the inner core is 10-25%, and the mass fraction of the natural plant fibers in the middle is 30-75%.

Furthermore, the volume fraction of the natural plant fibers in the composite material is 35-60%, the volume fraction of the high-strength fibers is 5-15%, the volume fraction and the mixing ratio can be set in a spinning structure and a layering structure according to requirements, and the thickness of the composite material plate can be set according to the number of layering layers.

Further, the hybrid fiber lay-up is woven in a plain weave (twill weave).

Further, a polytetrafluoroethylene film is attached to the surface of the flat plate mold.

Furthermore, the hot-press forming temperature is 170-185 ℃, and the hot-press pressure is 2-6 MPa.

The preparation method adopted by the invention comprises the following specific steps:

1) soaking natural plant fiber in 5-15% NaOH water solution for 10-24 h, and drying at 60-80 deg.C for 8-12 h;

2) carrying out surface treatment on the high-strength fibers, and drying for later use;

3) on a spinning machine, the high-strength fiber filaments obtained in the step 2) are used as an inner core, the natural plant fibers and the resin short fibers obtained in the step 1) are coated outside, twisting is carried out to form covering yarn warps (wefts), and then plain weave (twill) weaving is carried out to weave the hybrid fiber fabric for later use;

4) cleaning and drying the resin master batch, and hot-pressing the resin master batch on a flat vulcanizing machine to form a resin film layer with the thickness of 0.2-0.5mm for later use;

5) covering the upper and lower surfaces of the fabric obtained in the step 3) with two layers of resin film laminates obtained in the step 4), and sequentially and alternately laminating to prepare a laminate;

6) attaching a polytetrafluoroethylene film on a flat plate mold of a flat vulcanizing machine, placing the layered laminate obtained in the step 5) into the flat plate mold of the flat vulcanizing machine, carrying out mold pressing forming under the pressure of 2-6MPa and the temperature of 170-185 ℃, keeping the pressure for 1-3 minutes, after the forming process is finished, releasing the pressure, cooling to room temperature, and taking out the composite material plate from the mold cavity.

Compared with the prior art, the invention has the beneficial effects that:

the preparation method of the natural plant fiber hybrid composite material has the advantages of low production energy consumption, cyclic utilization, environmental friendliness, low price, more flexible designability and the like, can meet the requirements of green, energy-saving, environmental protection, low-cost mass production and the like, and compared with the traditional preparation method of the natural plant fiber reinforced composite material, the preparation method of the natural plant fiber hybrid composite material has the advantages of more excellent mechanical property, simpler and more convenient flow and can realize the mass production of the light-weight green composite material secondary bearing piece and even the bearing piece.

Drawings

Fig. 1 is a schematic diagram of the preparation of a natural plant fiber hybrid composite material.

In the figure: 1. the composite material comprises a flat plate mould, 2 parts of a polytetrafluoroethylene membrane, 3 parts of a resin film layer, 4 parts of weft yarns, 5 parts of warp yarns, 6 parts of an outer resin fiber layer, 7 parts of a middle natural plant fiber layer, 8 parts of an inner core high-strength fiber layer, 9 parts of a mixed fiber layer and 10 parts of a layer laminated object.

Detailed Description

The technical scheme of the invention is further explained and explained by combining the drawings as follows:

referring to fig. 1, in the preparation process of the composite material, firstly, two layers of resin film laminates 3 are respectively covered on the upper surface and the lower surface of a hybrid fiber laminate 9, and are sequentially and alternately laminated to form a laminate 10, and then the laminate 10 is put into a flat plate mold 1 of a flat vulcanizing machine attached with a polytetrafluoroethylene film 2 for hot press forming to prepare a composite material plate; the hybrid fiber lay-up 9 is a fabric woven by warp yarns 5 and weft yarns 4, wherein the warp yarns 5 (the weft yarns 4) comprise from outside to inside: an inner core high-strength fiber layer 8, a middle natural plant fiber layer 7 and an outer resin fiber layer 6.

The experiment or production example of the preparation method of the natural plant fiber hybrid composite material of the invention is as follows:

the preparation method of the traditional natural plant fiber reinforced composite material is mainly applied to non-bearing structural members and cannot be used on secondary bearing structures or even bearing structures due to the limitation of mechanical properties.