CN106189131A - Polylactic acid/the elastomer of the resistance to thermal conducting of ultra-toughness/carbon nano-particles composite or goods and preparation method thereof - Google Patents

Abstract

The super-tough heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product disclosed by the present invention is to melt and mix L-polylactic acid and carbon nanoparticles first, and then mix it with the elastomer containing D-polylactic acid segment Melt blending makes the L-polylactic acid matrix and the D-polylactic acid in the elastomer dispersed phase form a stereocomplex crystal on the phase interface of the blend, and the stereocomplex crystal can fix the carbon nanoparticles migrating between the two phases in the phase interface. On the interface, a composite with matrix crystallinity of 45.2-48.7%, heat-resistant temperature of 97.8-145.4°C, notched impact strength of 12.1-79.6kJ/m ² and electrical conductivity of 1.0× ^10-9-13.3S /m can be obtained. material or product. The method of the present invention can utilize the formed stereocomplex crystals to fix carbon nanoparticles on the phase interface, which not only effectively improves the interface strength, toughening efficiency and electrical conductivity of composite materials or products, but also accelerates the crystallization of the L-polylactic acid matrix, Improve the heat resistance of products.

Description

Super-tough, heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product and its preparation method

technical field

The invention belongs to the technical field of polymer composite materials and their preparation, and in particular relates to a super-tough, heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product and a preparation method thereof.

Background technique

Since the 20th century, polymer materials have been widely used in various sectors of the national economy and in all aspects of people's lives due to their excellent properties such as light weight, low price, and good flexibility. However, polymers that use petrochemical resources as synthetic raw materials The mass production and consumption of materials has also brought about two serious problems: the massive consumption of limited petroleum resources and the large amount of waste polymer materials that are difficult to degrade have caused serious pollution to the environment. Therefore, the development of biodegradable polymer materials using renewable resources as raw materials has become a research and application development hotspot in recent years.

Polylactic acid (PLA) is a bio-based, biodegradable green polymer, which can be prepared from plant resources such as corn as synthetic raw materials. It has the advantages of good biocompatibility, high mechanical strength, excellent transparency, and easy processing and molding. , known as the most promising biodegradable polymer material in this century. However, PLA is very brittle, its tensile elongation at break is only about 5%, and its notched impact strength is only 2kJ/m ² ; in addition, as a crystalline polymer, the crystallization speed of PLA is very slow, and injection molding, etc. Products made by ordinary melting processing methods are often in an amorphous state, resulting in the heat resistance of the product being restricted by its low glass transition temperature (55-60°C), and the heat resistance is very poor, and the heat distortion temperature is usually only 50-55 ℃ or so. These shortcomings greatly limit the wide application of PLA as a general-purpose plastic and engineering plastic to replace traditional petroleum-based polymer materials in the automotive industry, electronic appliances and other occasions that require high toughness and heat resistance.

Physical blending with elastomers (or flexible polymers) is a simple and economical way to improve the toughness of PLA. However, due to the poor thermodynamic compatibility between PLA and most elastomers, the interfacial interaction is very weak when the blend is formed, so that the toughening effect of the elastomer on the PLA matrix cannot be fully exerted. For example, in the system of polycaprolactone (PCL) toughened PLA, because the interface interaction between PLA and PCL is very weak, even if the addition of PCL reaches 20wt%, it can only make the notched impact strength of PLA from 2.2kJ/ ^m2 Increased to 5.2kJ/m ² (ACS Appl. Mater. Interfaces, 2012, 4, 897-905). Therefore, improving the interfacial interaction force between PLA and elastomer is the key to improving the toughening efficiency. It has been reported in the literature that the introduction of carbon nanoparticles into polymer blends can prepare high-performance polymer composites. Because the introduced carbon nanotubes, graphene and other carbon nanoparticles can be selectively dispersed on the phase interface of the blend and penetrate through the two-phase interface, the phase interface strength of the blend is significantly improved (Polymer, 2013, 54 , 464-471), and then obtain excellent toughening or strengthening effect. For example, the introduction of 2.0wt% modified carbon nanotubes in polypropylene/ethylene-vinyl acetate copolymer (PP/EVA) can increase the notched impact strength of the PP/EVA blend from the original 10.2kJ/ ^m2 to 63.2kJ/m ² (Polymer, 2009, 50, 3072-3078). Unfortunately, however, due to thermodynamic reasons, it is difficult for unmodified carbon nanoparticles to be stably distributed at the phase interface of the blend, which tends to migrate from one phase to interact with it during melt blending. The other phase, which is stronger, will still be selectively dispersed in one phase of the blend. Although, it has been found that carbon nanoparticles can be stably distributed on the blend phase interface by chemical or physical modification (Polymer, 2013, 54, 6165-6176; Biomacromolecules, 2009, 10, 417-424). However, the modification of carbon nanoparticles not only leads to a cumbersome and complicated process, but also because the process of using a strong oxidant to introduce active functional groups during modification will inevitably cause many defects on the surface of carbon nanoparticles, which will lead to its mechanical and electrical properties. deterioration. On the other hand, directly using elastomers and carbon nanoparticles to toughen PLA cannot effectively improve the crystallization rate of PLA at the same time, so that the PLA matrix in the processed and shaped products is still amorphous, and the heat resistance of the products is still poor. Therefore, how to find an effective way to achieve high-efficiency toughening of PLA by elastomers and carbon nanoparticles, and at the same time greatly accelerate the crystallization rate of PLA matrix, and obtain PLA composite materials or products with super toughness, heat resistance, and conductivity have become an important issue. A problem that needs to be solved urgently.

Contents of the invention

The purpose of the present invention is to solve the problems existing in the prior art, and firstly provide a preparation method of a super-tough, heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product.

Another object of the present invention is to provide a super-tough heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product prepared by the above method.

The preparation method of the super-tough, heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product provided by the present invention is characterized in that the method is to first melt and mix the L-lactic acid and the carbon nanoparticles to obtain the L-polylactic acid/ A premix of carbon nanoparticles, and then the resulting premix is melt-blended with the elastomer containing the D-polylactic acid segment, and the L-polylactic acid matrix molecular chain can be mixed with the elastomer in the dispersed phase of the melt-blended process. The D-polylactic acid molecular chain forms a stereocomplex crystal through stereocomplexation on the phase interface of the blend, and the stereocomplex crystal can act as a capture agent for carbon nanoparticles to fix the carbon nanoparticles migrating between the two phases on the phase interface , to solve the problem that unmodified carbon nanoparticles are difficult to stably distribute at the phase interface of incompatible blends, and then achieve the purpose of simultaneously improving the strength of the phase interface of the blend and the electrical conductivity of the composite material or product; at the same time, the stereo The composite crystal can also be used as a high-efficiency nucleating agent for the crystallization of the L-polylactic acid matrix to increase the crystallinity of the matrix, and finally obtain a polylactic acid/elastomer/carbon nanoparticle composite material or product with super-tough, heat-resistant and conductive properties.

The preparation method of the polylactic acid/elastomer/carbon nanoparticle composite material or product provided by the invention is characterized in that the specific process steps and conditions of the method are as follows:

1) Premix 0.1 to 10.0 parts of carbon nanoparticles and 99.9 to 90.0 parts of L-polylactic acid evenly, then add them to a melt mixer, and melt blend at a temperature of 170-210°C for 3-10 minutes to obtain L-polylactic acid/carbon a premix of nanoparticles;

2) Premix 5 to 50 parts of elastomers containing D-polylactic acid segments and 95 to 50 parts of L-polylactic acid/carbon nanoparticle premix evenly before adding them to a melt mixer, and heat them at a temperature of 170 to 210°C Melt and blend for 3-10 minutes, then granulate or reprocess and shape, and then the super-tough, heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product can be obtained.

In the above method, the parts of each material are parts by weight.

In the above method, the elastomer used to contain the dextrorotary polylactic acid segment comprises a graft or block copolymer of dextrorotary polylactic acid, preferably poly(ethylene-glycidyl methacrylate)-dextrorotary polylactic acid graft polymer , poly(ethylene-octene-glycidyl methacrylate)-dextropolylactic acid graft polymer, L-polylactic acid-polyethylene glycol-dextrorotary polylactic acid block copolymer or L-polylactic acid-polycaprolactone Either of the ester-dextrorotatory polylactic acid block copolymers.

In the above method, the weight-average molecular weight of the L-polylactic acid matrix used is ≥ 5×10 ⁴ g·mol ^-1 , and the optical purity is ≥ 95%.

In the above methods, the carbon nanoparticles used are preferably carbon nanotubes or graphene.

In the above method, the amount of carbon nanoparticles added is preferably 0.5-8.0 parts.

In the above method, the addition amount of the elastomer containing the D-polylactic acid segment is preferably 15-40 parts.

The super-tough heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product prepared by the above method provided by the present invention is characterized in that the content of carbon nanoparticle in the composite material or product is 0.1 to 5.0 wt%, containing The content of the elastomer of the D-polylactic acid chain segment is 5-50wt%, and the characteristic diffraction peaks of polylactic acid stereocomplex (SC) crystals are displayed on the wide-angle X-ray diffraction spectrum, and the carbon nanoparticles are dispersed by transmission electron microscopy. At the phase interface and through the two-phase interface, and the matrix crystallinity of the composite material or product is 45.2-48.7%, the heat-resistant temperature is 97.8-145.4°C, the notched impact strength is 12.1-79.6kJ/m ² , the electrical conductivity 1.0×10 ^-9 to 13.3 S/m.

When the content of carbon nanoparticles in the above-mentioned composite material or product is preferably 0.5 to 5.0 wt%, and the content of the elastomer containing the D-polylactic acid segment is preferably 15 to 40 wt%, the matrix crystallinity of the composite material or product is 46.5 to 5.0 wt%. 48.7%, the heat resistance temperature is 97.8~139.6℃, the notched impact strength is 34.1~79.6kJ/m ² , and the electrical conductivity is 5.2×10 ^-5 ~13.3S/m.

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

1. Since the preparation method provided by the present invention is to utilize the characteristics of polylactic acid having chiral molecules, the L-polylactic acid and carbon nanoparticles are first melt-mixed to obtain a premix of L-lactic acid/carbon nanoparticles, and then the resulting premixed The mixture is melt-blended with the elastomer containing the D-polylactic acid segment, and the stereocomplexity formed by the D-polylactic acid molecular chain in the elastomer and the L-polylactic acid matrix molecular chain in the blend interface area is used. Composite crystals are used to fix the carbon nanoparticles in the premix on the phase interface, so that there is no need to physically or chemically modify the carbon nanoparticles to achieve a stable distribution at the blend phase interface to achieve improved toughening efficiency The dual purposes of imparting electrical conductivity to the polylactic acid composite material also avoid a series of problems caused by the modification of carbon nanoparticles in the prior art.

2. Since the super-tough heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product provided by the present invention can not only make the D-polylactic acid molecular chain in the elastomer can combine with the L-polylactic acid molecular chain in the melt mixing process, The molecular chains of the lactic acid matrix in situ recombine at the interface to form stereocomplex (SC) crystals, and the SC crystals can act as a capture agent for carbon nanoparticles to fix part of the carbon nanoparticles migrating between the two phases in the phase of the blend. interface, to effectively improve the interfacial strength of the blend and the conductivity of the composite material or product, and because the melting point of the SC crystal is higher than the temperature of melt mixing and processing, it can also be used as an efficient nucleation during the melt cooling process It can accelerate the crystallization of L-polylactic acid matrix, increase the crystallinity of materials or products, and improve the heat resistance of products, so as to prepare super-tough, heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composites through melt processing technology. The material or product provides the possibility and is expected to greatly broaden the application range of polylactic acid materials.

3. Since the SC crystal formed by in-situ compounding in the preparation method provided by the present invention has high-efficiency nucleation, it can not only prepare high heat-resistant materials or products, but also greatly shorten the processing and molding cycle and reduce production costs.

4. The preparation method provided by the present invention has a simple and efficient process and is easy for industrial production.

Description of drawings

Figure 1 is the wide-angle X-ray diffraction (WAXD) pattern of interface crystals in the polylactic acid/elastomer/carbon nanoparticle composite material or product obtained in Examples 1-6 and Comparative Examples 1-2 of the present invention. It can be seen from the figure that the composite material or product prepared by the method of the present invention has the characteristic diffraction peaks of polylactic acid stereocomplex (SC) crystals at 12.0 °, 20.9 ° and 24.0 °, indicating that in the melt mixing process, in the elastomer The right-handed polylactic acid (PDLA) molecular chains and the left-handed polylactic acid (PLLA) matrix molecular chains formed SC crystals through stereocombination at the phase interface of the blend; while the WAXD maps of Comparative Examples 1 and 2 did not appear. Characteristic diffraction peaks, indicating that no SC crystals were formed in the elastomer-filled PLLA composites without D-PLA segments.

Fig. 2 is the semi-crystallization time-temperature curves of composite materials or products obtained in Examples 1 and 2 of the present invention and Comparative Examples 1 and 2 during isothermal crystallization. It can be seen from the curve that the polylactic acid composite material prepared by the method of the present invention has a very fast matrix crystallization rate.

Fig. 3 is a transmission electron microscope image of the blended material or product prepared in Example 2 and Comparative Example 2 of the present invention. It can be seen from the figure that Example 2 of the present invention constructs SC crystals at the interface of the PLLA matrix and the L-polylactic acid-polyethylene glycol-D-polylactic acid block copolymer, and the SC crystals finally promote the unmodified The carbon nanotubes are dispersed at the phase interface and run through the two-phase interface, while the carbon nanotubes of Comparative Example 2 are all dispersed in the elastomer phase. This shows that the interfacial SC crystals can act as a scavenger for unmodified carbon nanoparticles to fix the carbon nanoparticles migrating between the two phases on the phase interface of the blend, thereby significantly improving the impact toughness and durability of PLA composites or products. conductivity.

detailed description

The following examples are provided below to specifically describe the present invention, but it is necessary to point out that the following examples are only used to further illustrate the present invention, and cannot be interpreted as limiting the protection scope of the present invention. Those skilled in the art according to Summary of the present invention Some non-essential improvements and adjustments made to the present invention still belong to the protection scope of the present invention.

In addition, it is worth noting that: the notched impact strength, crystallinity, electrical conductivity and heat resistance parameters of the materials or products obtained in the following examples and comparative examples were obtained by using VJ-40 type (Chengde Jinjian Testing Instrument Co., Ltd.) cantilever Beam impact testing machine, American Perkin-Elmer pyris-1 differential scanning calorimeter (DSC), Keithley 6487 picoammeter and Q800 dynamic thermomechanical analyzer (US TA company) testing equipment test, the results are shown in the table below .

Example 1

1) Premix 1.4 parts of graphene and 98.6 parts of PLLA matrix with a weight-average molecular weight of 5×10 ⁴ g·mol ^-1 and an optical purity of 98%, and then add it to a melt mixer and melt it at a temperature of 170°C Blending for 3min to obtain a PLLA/graphene premix;

2) 30 parts of poly(ethylene-glycidyl methacrylate)-dextropolylactic acid grafted polymer and 70 parts of PLLA/graphene premix are mixed evenly and then added to the melt mixer, at a temperature of 190 ° C After melt blending for 10 minutes, granulation was carried out to prepare PLLA/poly(ethylene-glycidyl methacrylate)-dextrorotary polylactic acid graft polymer/graphene composite material.

Example 2

1) 2.5 parts of carbon nanotubes and 97.5 parts of PLLA matrix with a weight-average molecular weight of 1.1×10 ⁵ g·mol ^-1 and an optical purity of 95% were premixed uniformly, and then added to a melt mixer at a temperature of 180°C Melt blending for 5min to obtain a PLLA/carbon nanotube premix;

2) After mixing 20 parts of L-polylactic acid-polyethylene glycol-dextrorotary polylactic acid block copolymer and 80 parts of PLLA/carbon nanotube premix evenly, add them to the melt mixer, and melt the mixture at a temperature of 210°C. After mixing for 7 minutes, granulate to prepare the PLLA/L-polylactic acid-polyethylene glycol-D-polylactic acid block copolymer/carbon nanotube composite material, and continue to process the composite material into products.

Example 3

1) 4.7 parts of carbon nanotubes and 95.3 parts of PLLA matrix with a weight-average molecular weight of 1.5×10 ⁵ g·mol ^-1 and an optical purity of 98.5% were premixed uniformly, and then added to a melt mixer at a temperature of 190°C Melt blending for 7min to obtain a PLLA/carbon nanotube premix;

2) 15 parts of poly(ethylene-octene-glycidyl methacrylate)-dextrorotary polylactic acid grafted polymer and 85 parts of PLLA/carbon nanotube premixes are mixed uniformly and then added to the melt mixer. Melt blending at 200° C. for 5 minutes and then granulation to prepare PLLA/poly(ethylene-octene-glycidyl methacrylate)-dextro-polylactic acid graft polymer/carbon nanotube composite material.

Example 4

1) 1.0 parts of carbon nanotubes and 99.0 parts of PLLA matrix with a weight-average molecular weight of 2.1×10 ⁵ g·mol ^-1 and an optical purity of 98.5% were pre-mixed uniformly, and then added to a melt mixer at a temperature of 200°C Melt blending for 10min to obtain a PLLA/carbon nanotube premix;

2) After mixing 50 parts of poly(ethylene-glycidyl methacrylate)-dextropolylactic acid graft polymer and 50 parts of PLLA/carbon nanotube premix evenly, add it to the melt mixer, and heat it at a temperature of 190°C Melt blending for 3min and then granulate to prepare the PLLA/poly(ethylene-glycidyl methacrylate)-dextropolylactic acid grafted polymer/carbon nanotube composite material, and utilize a micro-injection molding machine to continue at 170°C , to process composite materials into products.

Example 5

1) 8.3 parts of carbon nanotubes and 91.7 parts of PLLA matrix with a weight-average molecular weight of 2.1×10 ⁵ g·mol ^-1 and an optical purity of 98.5% were pre-mixed uniformly, and then added to a melt mixer at a temperature of 210°C Melt blending for 5min to obtain a PLLA/carbon nanotube premix;

2) 40 parts of poly(ethylene-glycidyl methacrylate)-dextropolylactic acid grafted polymer and 60 parts of PLLA/carbon nanotube premix are mixed evenly and then added to the melt mixer, at a temperature of 180 ° C Melt blending at low temperature for 7 minutes and then granulation to prepare PLLA/poly(ethylene-glycidyl methacrylate)-dextrorotary polylactic acid graft polymer/carbon nanotube composite material.

Example 6

1) Premix 0.1 parts of graphene and 99.9 parts of PLLA matrix with a weight-average molecular weight of 2.1×10 ⁵ g·mol ^-1 and an optical purity of 98.5%, and then add it to a melting mixer and melt it at a temperature of 190°C Blending for 5min to obtain a PLLA/graphene premix;

2) Mix 5 parts of L-polylactic acid-polycaprolactone-D-polylactic acid block copolymer and 95 parts of PLLA/graphene premix evenly, then add them to the melt mixer, and melt blend at a temperature of 170°C After 5 minutes, granulate to prepare a PLLA/L-polylactic acid-polycaprolactone-D-polylactic acid block copolymer/graphene composite material, and use a micro-injection molding machine to continue processing the composite material into a product at 190°C.

Comparative example 1

1) Premix 1.4 parts of graphene and 98.6 parts of PLLA matrix with a weight-average molecular weight of 5×10 ⁴ g·mol ^-1 and an optical purity of 98%, and then add it to a melt mixer and melt it at a temperature of 170°C Blending for 3min to obtain a PLLA/graphene premix;

2) After mixing 30 parts of poly(ethylene-glycidyl methacrylate)-L-polylactic acid graft polymer and 70 parts of PLLA/graphene premix evenly, add it to a melting mixer and melt at a temperature of 190°C After blending for 10 minutes, the mixture was granulated to prepare a PLLA/poly(ethylene-glycidyl methacrylate)-L-polylactic acid graft polymer/graphene composite material.

Comparative example 2

1) 2.5 parts of carbon nanotubes and 97.5 parts of PLLA matrix with a weight-average molecular weight of 1.1×10 ⁵ g·mol ^-1 and an optical purity of 95% were premixed uniformly, and then added to a melt mixer at a temperature of 180°C Melt blending for 5min to obtain a PLLA/carbon nanotube premix;

2) Mix 20 parts of L-polylactic acid-polyethylene glycol-L-polylactic acid block copolymer and 80 parts of PLLA/carbon nanotube premix evenly, add them to the melt mixer, and melt blend at a temperature of 210°C After 7 minutes, it was granulated to prepare a PLLA/L-polylactic acid-polyethylene glycol-L-polylactic acid block copolymer/carbon nanotube composite material, and the composite material was processed into products by using a micro injection molding machine at 210°C.

In order to investigate the relevant properties of the polylactic acid/elastomer/carbon nanoparticle composite material or product, the present invention characterizes the crystals of the interface crystallization of the composite material obtained in Examples 1-6 and Comparative Examples 1-2 with wide-angle X-ray diffraction (WAXD) Type, the results are shown in Fig. 1; Evaluated the matrix crystallization rate of the composite material of the embodiment of the present invention 1 and 2 with comparative examples 1 and 2 with differential scanning calorimeter (DSC), the results are shown in Fig. 2; with transmission electron microscope ( TEM) characterized the selective distribution of carbon nanoparticles in the composite material obtained in Example 2 and Comparative Example 2, and the results are shown in Figure 3; the notched impact toughness of the materials or products obtained in Examples 1 to 6 and Comparative Examples 1 to 2 were tested. , crystallinity determination, conductivity determination and dynamic mechanical property analysis (DMA) test, the results are shown in the table below.

surface

*: It is the corresponding temperature when the storage modulus decreases to 200Mpa on the DMA storage modulus-temperature curve of the material or product (the storage modulus decreases with the increase of the test temperature).

It can be seen from the above table that since the PDLA molecular chains in the elastomer form SC crystals by stereocombining with the PLLA matrix molecular chains in the phase interface region of the blend, not only can the carbon nanoparticles migrating between the two phases be fixed on the phase interface, Furthermore, the purpose of simultaneously improving the notched impact toughness and electrical conductivity of the polylactic acid composite material or product can be achieved, and the heat resistance of the product can be significantly improved by greatly increasing the crystallinity of the matrix.

Claims (10)

1. A preparation method of super-tough heat-resistant conductive polylactic acid/elastomer/carbon nanoparticle composite material or products, characterized in that the method is to melt and mix L-lactic acid and carbon nanoparticles to obtain L-polylactic acid/carbon nanoparticle A premix of carbon nanoparticles, and then the resulting premix is melt-blended with the elastomer containing the D-polylactic acid segment, and the L-polylactic acid matrix molecular chain can be mixed with the elastomer in the dispersed phase of the melt-blended process. The D-polylactic acid molecular chain forms a stereocomplex crystal through stereocomplexation on the phase interface of the blend, and the stereocomplex crystal can act as a capture agent for carbon nanoparticles to fix the carbon nanoparticles migrating between the two phases on the phase interface , to solve the problem that unmodified carbon nanoparticles are difficult to stably distribute at the phase interface of incompatible blends, and then achieve the purpose of simultaneously improving the phase interface strength of the blend and the electrical conductivity of the composite material or product; at the same time, the stereocomposition The crystal can also be used as an efficient nucleating agent for the crystallization of the L-polylactic acid matrix to increase the crystallinity of the matrix, and finally obtain a polylactic acid/elastomer/carbon nanoparticle composite material or product with super-tough, heat-resistant and conductive properties. 2. the preparation method of the polylactic acid/elastomer/carbon nanoparticle composite material or goods of super-tough heat-resistant and conductive polylactic acid according to claim 1, it is characterized in that the specific process steps and conditions of the method are as follows: 1) Premix 0.1 to 10.0 parts of carbon nanoparticles and 99.9 to 90.0 parts of L-polylactic acid evenly, then add them to a melt mixer, and melt blend at a temperature of 170-210°C for 3-10 minutes to obtain L-polylactic acid/carbon a premix of nanoparticles; 2) Mix 5-50 parts of elastomers containing D-polylactic acid segments and 95-50 parts of L-polylactic acid/carbon nanoparticle premix evenly, then add them to a melting mixer, and melt at a temperature of 170-210°C After blending for 3 to 10 minutes, granulation or reprocessing can produce super-tough, heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite materials or products. The parts of each of the above materials are parts by weight. 3. according to claim 1 and the preparation method of the polylactic acid/elastomer/carbon nanoparticle composite material or goods of super-tough heat-resisting electric conduction described in claim 1, it is characterized in that used in the method contains the elasticity of d-polylactic acid segment The body is a graft or block copolymer of D-polylactic acid. 4. according to the preparation method of the polylactic acid/elastomer/carbon nanoparticle composite material or goods of supertough heat-resistant and conductive described in claim 1 or 2, it is characterized in that used carbon nanoparticle is carbon nanotube or graphite in the method alkene. 5. the preparation method of polylactic acid/elastomer/carbon nanoparticle composite material or goods of supertough heat-resistant and conductive polylactic acid according to claim 3, it is characterized in that used carbon nanoparticle is carbon nanotube or graphene in this method. 6. the preparation method of the polylactic acid/elastomer/carbon nanoparticle composite material or goods of super-tough heat-resistant and conductive polylactic acid according to claim 2, it is characterized in that the elastomer used in the method contains the d-polylactic acid segment The addition amount is 15-40 parts; the addition amount of carbon nanoparticles is 0.5-8.0 parts. 7. the preparation method of the polylactic acid/elastomer/carbon nanoparticle composite material or goods of super-tough heat-resistant and conductive polylactic acid according to claim 3, it is characterized in that the elastomer used in the method contains the d-polylactic acid segment The addition amount is 15-40 parts; the addition amount of carbon nanoparticles is 0.5-8.0 parts. 8. the preparation method of the polylactic acid/elastomer/carbon nanoparticle composite material or goods of super-tough heat-resistant and conductive polylactic acid according to claim 5, it is characterized in that the elastomer used in the method contains the d-polylactic acid segment The addition amount is 15-40 parts; the addition amount of carbon nanoparticles is 0.5-8.0 parts. 9. A polylactic acid/elastomer/carbon nanoparticle composite material or product prepared by the method described in claim 1 or 2, characterized in that the carbon nanoparticle content in the composite material or product is 0.1 ～5.0wt%, the content of the elastomer containing the dextrorotatory polylactic acid segment is 5～50wt%, on the wide-angle X-ray diffraction pattern, show the characteristic diffraction peak of polylactic acid stereocomplex (SC) crystal, by transmission electron microscope Observation shows that carbon nanoparticles are dispersed at the phase interface and penetrate the two-phase interface, and the matrix crystallinity of the composite material or product is 45.2-48.7%, the heat-resistant temperature is 97.8-145.4°C, and the notched impact strength is 12.1-79.6kJ /m ² , and the electrical conductivity is 1.0×10 ^-9 to 13.3 S/m. 10. The super-tough heat-resistant and conductive polylactic acid/elastomer/carbon nanoparticle composite material or product according to claim 9, characterized in that the carbon nanoparticle content in the composite material or product is 0.5～5.0wt%, containing The content of the elastomer of the D-polylactic acid segment is 15-40wt%, the matrix crystallinity of the composite material or product is 46.5-48.7%, the heat-resistant temperature is 97.8-139.6°C, and the notched impact strength is 34.1-79.6kJ/ m ² , and the electrical conductivity is 5.2×10 ^-5 to 13.3 S/m.