CN111673969A - Polylactic acid transparent material with high impact strength and preparation method thereof - Google Patents
Polylactic acid transparent material with high impact strength and preparation method thereof Download PDFInfo
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- CN111673969A CN111673969A CN202010553149.8A CN202010553149A CN111673969A CN 111673969 A CN111673969 A CN 111673969A CN 202010553149 A CN202010553149 A CN 202010553149A CN 111673969 A CN111673969 A CN 111673969A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/003—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor characterised by the choice of material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
- B29K2067/04—Polyesters derived from hydroxycarboxylic acids
- B29K2067/046—PLA, i.e. polylactic acid or polylactide
Abstract
The invention provides a preparation method of a polylactic acid transparent material with high impact strength, which comprises the following steps: s1) forming polylactic acid to obtain a parison; s2) stretching the parison above the glass transition temperature, cooling and solidifying to obtain the polylactic acid transparent material with high impact strength. Compared with the prior art, the pure polylactic acid material is stretched above the glass transition temperature, the condensation entanglement network of the pure polylactic acid material is recombined in the stretching process, the molecular chains are oriented and arranged along the stretching direction, and a highly oriented fibrous microstructure is formed in the system, so that the polylactic acid material can be greatly enhanced and toughened without adding any auxiliary agent, the rigidity and the strength of the material are improved, and the method is easy to operate and realize; meanwhile, no elastomer is added, so that no phase separation exists in the system, and the polylactic acid material not only has transparency, but also shows the numerical value of ultrahigh notch impact strength, thereby having good development prospect.
Description
Technical Field
The invention belongs to the technical field of high polymer materials, and particularly relates to a polylactic acid transparent material with high impact strength and a preparation method thereof.
Background
In recent years, with the increasing severity of the problems of shortage of petroleum-based resources, non-degradable pollution of white plastics, etc., the development and utilization of biomass-derived raw materials and the preparation of biodegradable polymer materials have been receiving attention and attention. Meanwhile, due to the advanced development of material science, the existing functional materials cannot meet the actual requirements of human beings. Therefore, it is a major trend to develop a high-performance degradable and excellent comprehensive performance polymer material and expand its application field.
Polylactic acid is an environment-friendly biomass-derived plastic, has the advantages of excellent biocompatibility, processability, degradability and the like, has the reputation of 'green plastic', and has attracted more and more attention in recent years. However, the pure polylactic acid material still has the key technical bottleneck problems of high brittleness and poor heat resistance, which severely limits the wide application of the pure polylactic acid material in various fields. Therefore, the modification research on the polylactic acid material is becoming a subject and application research hotspot, and especially the toughening modification research on the polylactic acid material is widely carried out.
At present, the modification research of polylactic acid at home and abroad can be mainly divided into two categories:
the first is modification by chemical method, i.e. modification from molecular chain structure, and changing the molecular chain structure of polylactic acid by copolymerization, grafting, crosslinking and other methods. Synthetic polylactic acid-polycaprolactone-polylactic acid multi-block copolymers are reported to have an ultimate breaking strength of 32MPa, a Young's modulus as low as 30MPa, and an elongation at break much higher than 600% (Cohn D, Salomon AH. designing biogradeable multiblock PCL/PLA thermoplastic elastomers. biomaterials,26(15), 2297-; two types of polylactic acid-containing triblock copolymers, polylactic acid-polypropylene glutaric acid-polylactic acid and polylactic acid-polybutylene glutarate pimelic acid-polylactic acid copolymers, have been recently reported, wherein the most plastic samples of the two types of polylactic acid modified materials have tensile yield strength and elongation at break of 26.8MPa and 141% and 30.6MPa and 379%, respectively (WeiZY, et al. ABA triblock copolymers of poly (L-lactic acid) A hard blocks: organic polyesters of amorphous and crystalline aliphatic polyesters B soft blocks.106polymeric Testing 83 (348)), but the process produces elastomeric materials that are still predominantly plastic and do not have the necessary impact resistance tests.
The second type is modification by a physical method, namely modification in a matching mode from the matter composition, and other materials such as micromolecular plasticizers, toughening agents or nano particles are added into the polylactic acid by methods such as plasticization, blending or compounding, so that the impact resistance of the polylactic acid is effectively improved. Chinese patent with publication No. CN108659491 discloses polylactic acid and particles with the average particle size of less than 50 μm, which are melted, blended and molded, and are drawn in a single-direction hot manner to prepare a high-strength, high-modulus and high-toughness polylactic acid composite material, the elongation at break of which can reach about 163%, and the material has higher tensile strength and Young modulus, but the impact resistance of the material is not involved in the patent, and the composite material is not a pure polylactic acid material; chinese patent with publication No. CN106977887 discloses that a layered double-hydroxy metal oxide and caprolactone are mixed to obtain a reactant, ring-opening polymerization is carried out to obtain a modified layered double-hydroxy metal oxide, the modified layered double-hydroxy metal oxide and polylactic acid are melted, isocyanate is used as a chain extender to prepare a toughened modified polylactic acid material, the prepared toughened modified polylactic acid material shows good impact resistance and toughness, and the notch impact strength of the toughened modified polylactic acid material is 12KJ/m2The elongation at break is 89% and the tensile strength is 52MPa, and the impact resistance of the material is not referred to in the patent, and the composite material is not a pure polylactic acid material.
There is also a document that a polylactic acid sheet with improved mechanical properties, in particular toughness, is obtained by uniaxial pre-stretching around the glass transition temperature of polylactic acid, and the tensile yield strength and elongation at break of the most plastic sample are 63.6MPa and 152% respectively, but there is no report of impact resistance tests (Chen YJ, example. insulation index by simple uniform pre-stretching as a key factor for exterior poly (L-lactic acid) sheets.polymer 140,47-55 (2018)).
There is also a document reporting that the young's modulus and elongation at break of the most plastic samples can be increased to 2.2GPa and 315% respectively by means of super-cooled melt drawing above the glass transition temperature, but there is no report on the impact resistance test performance (Razavi m., & Wang s.q. when is crystalline poly (lactic acid) short at temperature.
Although the method can improve the impact resistance of the polylactic acid to a certain extent, the chemical method has complex process and higher requirement on equipment, and the used solvent is easy to pollute the environment and is not suitable for industrial production; the physical modification method is simple, convenient, economic and effective, is suitable for large-scale industrial production, is an advantageous method for modifying and applying polylactic acid, and still needs to improve the impact resistance.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a transparent polylactic acid material with high impact strength and a preparation method thereof.
The invention provides a preparation method of a polylactic acid transparent material with high impact strength, which comprises the following steps:
s1) forming polylactic acid to obtain a parison;
s2) stretching the parison above the glass transition temperature, cooling and solidifying to obtain the polylactic acid transparent material with high impact strength.
Preferably, the polylactic acid is dried and then molded in the step S1).
Preferably, the drying temperature is 20-90 ℃; the drying time is 1-72 h.
Preferably, the molding method is injection molding or compression molding; the compression molding temperature is 160-250 ℃; the compression molding pressure is 2-12 MPa; the compression molding time is 1-300 min; the temperature of cooling and solidifying is 0-40 ℃.
Preferably, the temperature of the stretching treatment in the step S2) is 55-100 ℃; the strain of the stretching treatment is 5-1200%.
Preferably, the temperature of the stretching treatment in the step S2) is 60-70 ℃; the strain of the stretching treatment is 300-700%.
Preferably, the stretching rate of the stretching treatment in the step S2) is 0.5 to 1000 mm/min.
Preferably, the stretching rate of the stretching treatment in the step S2) is 1 to 50 mm/min.
The invention also provides the polylactic acid transparent material with high impact strength prepared by the method.
Preferably, the high impact strength polylactic acid transparent material has impact strength of 127-231 KJ/m2。
The invention provides a preparation method of a polylactic acid transparent material with high impact strength, which comprises the following steps: s1) forming polylactic acid to obtain a parison; s2) stretching the parison above the glass transition temperature, cooling and solidifying to obtain the polylactic acid transparent material with high impact strength. Compared with the prior art, the pure polylactic acid material is stretched above the glass transition temperature, the condensation entanglement network of the pure polylactic acid material is recombined in the stretching process, the molecular chains are oriented and arranged along the stretching direction, and a highly oriented fibrous microstructure is formed in the system, so that the polylactic acid material can be greatly enhanced and toughened without adding any auxiliary agent, the rigidity and the strength of the material are improved, and the method is easy to operate and realize; meanwhile, no elastomer is added, so that no phase separation exists in the system, and the polylactic acid material not only has transparency, but also shows the numerical value of ultrahigh notch impact strength, thereby having good development prospect.
Experiments show that the breaking strength of the pure polylactic acid transparent material obtained by stretching treatment above the glass transition temperature is improved from 60MPa to 172MPa, the breaking elongation is improved from 6 percent to 21-91 percent, and the notch impact strength is improved from 2.4KJ/m2Increased to 231KJ/m2The reinforcing and toughening effects are very obviousIt is noted that.
Drawings
FIG. 1 is a stress-strain curve diagram of a pure polylactic acid transparent material sample obtained in examples 1 to 6 of the present invention;
FIG. 2 is a diagram showing the sample strips in example 6 of the present invention after reaching a predetermined strain and being cooled and solidified in an air atmosphere at room temperature;
FIG. 3 is a drawing showing an entire sample taken out of the sample after stretching and cooling in example 6 of the present invention;
FIG. 4 is a pictorial representation of a cut-out specimen (top) and an impact test specimen (bottom) for a notch of a sample removed by cooling after stretching in example 6 of the present invention;
FIG. 5 is a graph showing the relationship between notched Izod impact strength and strain of the pure polylactic acid transparent material samples obtained in examples 1 to 6 and comparative example 1 of the present invention;
FIG. 6 is a stress-strain curve diagram of the room temperature secondary stretching of the pure polylactic acid transparent material samples obtained in examples 1-5, example 7 and comparative example 1 of the present invention;
FIG. 7 is a graph showing the relationship between Young's modulus and strain of the pure polylactic acid transparent material samples obtained in examples 1 to 5, 7 and comparative example 1 of the present invention after twice stretching at room temperature;
FIG. 8 is a graph showing the relationship between the elongation at break and the strain at room temperature in the secondary stretching of the pure polylactic acid transparent material samples obtained in examples 1 to 5, 7 and comparative example 1 of the present invention;
FIG. 9 is a graph showing the relationship between the breaking strength and the strain of the pure polylactic acid transparent material samples obtained in examples 1 to 5, 7 and comparative example 1 of the present invention in the room temperature secondary stretching;
FIG. 10 is a graph showing the relationship between tensile toughness and strain of the pure polylactic acid transparent material samples obtained in examples 1 to 5, 7 and comparative example 1 of the present invention after secondary stretching at room temperature;
FIG. 11 is a graphical representation of SEM brittle sections of samples obtained in example 4 of the present invention and comparative example 1;
FIG. 12 is a wide angle-X-ray diffraction pattern of the samples obtained in example 2, example 4 and comparative example 1 of the present invention;
FIG. 13 is a pictorial view of a cut-out specimen and an impact test specimen for a notch of a sample removed by cooling after stretching in example 8 of the present invention;
FIG. 14 is a pictorial view of a cut-out specimen and an impact test specimen for a notch from a sample removed by cooling after stretching in example 9 of the present invention;
FIG. 15 is a pictorial representation of a cut-out specimen and an impact test specimen for a notch from a sample removed by cooling after stretching in example 10 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a preparation method of a polylactic acid transparent material with high impact strength, which comprises the following steps: s1) forming polylactic acid to obtain a parison; s2) stretching the parison above the glass transition temperature, cooling and solidifying to obtain the polylactic acid transparent material with high impact strength.
The pure polylactic acid material is stretched above the glass transition temperature, the condensed entangled network is recombined in the stretching process, molecular chains are oriented and arranged along the stretching direction, and a highly oriented fibrous microstructure is formed in the system, so that the polylactic acid material can be greatly reinforced and toughened without adding any auxiliary agent, and the method is easy to operate and realize; meanwhile, no elastomer is added, so that no phase separation exists in the system, and the polylactic acid material not only has transparency, but also shows the numerical value of ultrahigh notch impact strength, thereby having good development prospect.
In the present invention, the sources of all raw materials are not particularly limited, and they may be commercially available.
Forming polylactic acid to obtain a parison; the polylactic acid is preferably dried and then molded; the drying temperature is preferably 20-90 ℃, more preferably 40-90 ℃, further preferably 50-80 ℃, and most preferably 60-70 ℃; in the present invention, the polylactic acid may be amorphous polylactic acid or crystalline polylactic acid; when the polylactic acid is amorphous polylactic acid, preferably drying at a lower temperature, wherein the drying temperature is preferably 23-45 ℃; when the polylactic acid is crystalline polylactic acid, the drying temperature is preferably 65-90 ℃; in addition, a dehumidification dryer special for polylactic acid can be used for drying; the drying time is preferably 1-72 hours, more preferably 5-60 hours, still more preferably 5-40 hours, still more preferably 8-20 hours, and most preferably 12-15 hours; drying the polylactic acid can prevent moisture from increasing the thermal degradation of the polylactic acid in the subsequent injection molding or compression molding process; the molding method is preferably injection molding or compression molding; the compression molding temperature is preferably 160-250 ℃, more preferably 170-230 ℃, further preferably 180-220 ℃, and most preferably 200 ℃; the pressure for compression molding is preferably 2-12 MPa, more preferably 5-12 MPa, still more preferably 8-12 MPa, and most preferably 10 MPa; the compression molding time is preferably 1-300 min, more preferably 5-200 min, still more preferably 5-100 min, still more preferably 5-50 min, and most preferably 10-20 min; after compression molding, preferably quenching by ice water to cool the mixture to room temperature to obtain a parison; the size of the "parison" is not particularly limited, and the "parison" is usually molded into a different size depending on the mold of the molding press, and may be, for example, 0.5 to 16mm thick, 10 to 80mm wide, and 50 to 150mm long. Depending on the size of the parison, the material to be stretch-formed may include films, sheets, blocks, etc.
Stretching the parison above the glass transition temperature; the stretching rate, the stretching temperature and the stretching strain determine the mechanical property of the material after stretching treatment; in the invention, the temperature of the stretching treatment is preferably 55-100 ℃, more preferably 60-90 ℃, further preferably 60-80 ℃, and most preferably 60-70 ℃; in some embodiments provided herein, the temperature of the stretching treatment is preferably 60 ℃; in some embodiments provided herein, the temperature of the stretching treatment is preferably 70 ℃; in some embodiments provided herein, the temperature of the stretching treatment is preferably 80 ℃; the stretching rate of the stretching treatment is preferably 0.5-1000 mm/min, more preferably 1-500 mm/min, still more preferably 1-200 mm/min, still more preferably 1-100 mm/min, and most preferably 1-50 mm/min; in some embodiments provided herein, the stretching process preferably has a stretching rate of 20 mm/min; in some embodiments provided herein, the stretching process preferably has a stretching rate of 1 mm/min; in other embodiments provided herein, the stretching process preferably has a stretching rate of 50 mm/min; the strain of the stretching treatment is preferably 5% to 1200%, more preferably 20% to 1000%, still more preferably 50% to 1000%, still more preferably 100% to 800%, still more preferably 100% to 700%, most preferably 300% to 700%; in some embodiments provided herein, the strain of the stretching treatment is preferably 100%; in some embodiments provided herein, the stretching treatment preferably has a strain of 200%; in some embodiments provided herein, the strain of the stretching treatment is preferably 300%; in some embodiments provided herein, the strain of the stretching treatment is preferably 400%; in some embodiments provided herein, the strain of the stretching treatment is preferably 500%; in some embodiments provided herein, the strain of the stretching treatment is preferably 650%; in other embodiments provided herein, the strain of the stretching process is preferably 700%.
After stretching treatment, cooling and solidifying to obtain the polylactic acid transparent material with high impact strength; the temperature for cooling and solidifying is preferably 0 ℃ to 40 ℃, and the cooling and solidifying is more preferably carried out at room temperature.
The invention carries out stretching treatment above the glass transition temperature to ensure that the pure polylactic acid parison obtains a highly oriented fiberized microstructure, thereby obviously improving the rigidity and the strength of the material. The breaking strength of the polylactic acid material which is stretched above the glass transition temperature is improved from 60MPa to 172MPa, the breaking elongation is improved from 6 percent to 21 percent to 91 percent, and the notch impact strength is improved from 2.4KJ/m2Increased to 231KJ/m2Enhancement andthe toughening effect is very obvious.
Compared with other toughening methods, the toughening method of stretching treatment above the glass transition temperature does not need to add any auxiliary agent, is easy to operate, does not change the biodegradability of the material, can improve various mechanical properties of the material, and has good development prospect.
The stretching treatment toughening method above the glass transition temperature can also induce the polylactic acid to be converted from an amorphous state to an oriented crystalline state, and can endow the material with more excellent heat resistance while strengthening and toughening the pure polylactic acid material.
And the pure polylactic acid material obtains high transparency under the condition of not adding any auxiliary agent by a stretching treatment toughening method above the glass transition temperature, thereby greatly widening the application field of the material.
The invention also provides a high-impact strength polylactic acid transparent material prepared by the method; the impact strength of the high-impact-strength polylactic acid transparent material is preferably 127-231 KJ/m2。
The pure polylactic acid transparent material with ultrahigh impact strength obtained by the preparation method can be used for manufacturing packaging materials, fibers, non-woven fabrics and the like, and can be used in the fields of clothing (underwear and outerwear), industry (construction industry, agriculture, forestry, paper making, automobile manufacturing industry), sanitary medical appliances and the like.
In order to further illustrate the present invention, the following will describe a high impact strength polylactic acid transparent material and a preparation method thereof in detail with reference to the following examples.
The reagents used in the following examples are all commercially available. Polylactic acid starting materials used in the examples were all purchased from Natureworks corporation under the designation 2003D. The density of the sample was 1.24g/cm3The melt flow index was 6g/(10min) (210 ℃ C., 2.16 kg). The results of Gel Permeation Chromatography (GPC) showed that the weight average molecular weight of the polylactic acid sample was 296kg/mol, and the dispersion index was 2.3; the impact performance test in the embodiment of the invention is carried out according to the standard GB/T1843-2008; the tensile test was carried out according to the standard GB/T1040.3-2006.
Example 1
The polylactic acid raw material dried for 12h at the temperature of 60 ℃ is molded into preforms of 6 multiplied by 15 multiplied by 100mm (for preparing impact sample bars) and 3 multiplied by 30 multiplied by 100mm (for preparing secondary tensile sample bars) in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature by ice water quenching. And (3) stretching the blank on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching speed is 20mm/min, the stretching strain is 100%, and after the preset strain is reached, the blank is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with the stretching strain of 100%.
The tensile-treated samples were cut to prepare 3X 80X 10mm notched rectangular impact bars and 1X 4X 50mm dumbbell-shaped tensile bars, which were then subjected to impact and tensile tests, respectively.
Example 2
The polylactic acid material dried at 60 ℃ for 12h is molded into preforms of 6X 18X 100mm (for preparing impact bars) and 3X 30X 100mm (for preparing secondary tensile bars) in a film pressing machine at 200 ℃ under 10MPa for 10min, and the samples are cooled to room temperature by ice water quenching. And (3) stretching the blank on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching speed is 20mm/min, the stretching strain is 200%, and after the preset strain is reached, the blank is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with the stretching strain of 200%.
The tensile-treated samples were cut to prepare 3X 80X 10mm notched rectangular impact bars and 1X 4X 50mm dumbbell-shaped tensile bars, which were then subjected to impact and tensile tests, respectively.
Example 3
The polylactic acid material dried at 60 ℃ for 12h is molded into preforms of 6X 22X 100mm (for preparing impact bars) and 3X 30X 100mm (for preparing secondary tensile bars) in a film pressing machine at 200 ℃ under 10MPa for 10min, and the samples are cooled to room temperature by ice water quenching. And (3) stretching the parison on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching speed is 20mm/min, the strain is 300%, and after the preset strain is reached, the parison is cooled and solidified in the air environment at room temperature to obtain the pure polylactic acid transparent material sample with ultrahigh impact strength.
The tensile-treated samples were cut to prepare 3X 80X 10mm notched rectangular impact bars and 1X 4X 50mm dumbbell-shaped tensile bars, which were then subjected to impact and tensile tests, respectively.
Example 4
The polylactic acid material dried at 60 ℃ for 12h is molded into preforms of 9X 20X 100mm (for preparing impact bars) and 3X 30X 100mm (for preparing secondary tensile bars) in a film pressing machine at 200 ℃ under 10MPa for 10min, and the samples are cooled to room temperature by ice water quenching. And (3) stretching the blank on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching speed is 20mm/min, the stretching strain is 400%, and after the preset strain is reached, the blank is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with ultrahigh impact strength.
The tensile-treated samples were cut to prepare 3X 80X 10mm notched rectangular impact bars and 1X 4X 50mm dumbbell-shaped tensile bars, which were then subjected to impact and tensile tests, respectively.
Example 5
The polylactic acid raw material dried for 12h at the temperature of 60 ℃ is molded into preforms of 6 multiplied by 30 multiplied by 100mm (for preparing impact sample bars) and 3 multiplied by 30 multiplied by 100mm (for preparing secondary tensile sample bars) in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature by ice water quenching. And (3) stretching the parison on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching speed is 20mm/min, the stretching strain is 500 percent, and after the preset strain is reached, the parison is cooled and solidified in the air environment at room temperature to obtain the pure polylactic acid transparent material sample with ultrahigh impact strength.
The tensile-treated samples were cut to prepare 3X 80X 10mm notched rectangular impact bars and 1X 4X 50mm dumbbell-shaped tensile bars, which were then subjected to impact and tensile tests, respectively.
Example 6
The polylactic acid raw material dried for 12h at the temperature of 60 ℃ is molded into a parison with the thickness of 6 multiplied by 30 multiplied by 100mm (used for preparing an impact sample strip) in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature through ice water quenching. And (3) stretching the parison on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching strain is 650 percent, and after the preset strain is reached, the parison is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with ultrahigh impact strength.
The samples after the stretching treatment were cut to prepare rectangular impact specimens of 3X 80X 10mm with notches, and then subjected to an impact test.
Example 7
The polylactic acid raw material dried for 12h at the temperature of 60 ℃ is molded into a parison with the thickness of 3 multiplied by 30 multiplied by 100mm (used for preparing a secondary tensile sample strip) in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature through ice water quenching. And (3) stretching the parison on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching speed is 20mm/min, the stretching strain is 700 percent, and after the preset strain is reached, the parison is cooled and solidified in the air environment at room temperature to obtain the pure polylactic acid transparent material sample with ultrahigh impact strength.
The sample after the stretching treatment was cut to prepare 1X 4X 50mm dumbbell-shaped tensile specimens, which were then subjected to a tensile test.
Example 8
The polylactic acid raw material dried for 12 hours at the temperature of 60 ℃ is molded into a parison with the thickness of 3 multiplied by 30 multiplied by 100mm in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature by ice water quenching. And (3) stretching the blank on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching speed is 50mm/min, the stretching strain is 400%, and after the preset strain is reached, the blank is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with ultrahigh impact strength.
Cutting the stretched sample to prepare a rectangular impact sample strip with a notch of 3 × 80 × 10mm, and then performing impact test to obtain the polylactic acid material sample with the notch impact strength of 190KJ/m2。
Example 9
The polylactic acid raw material dried for 12 hours at the temperature of 60 ℃ is molded into a parison with the thickness of 3 multiplied by 30 multiplied by 100mm in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature by ice water quenching. And (3) stretching the blank on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 70 ℃, the stretching speed is 1mm/min, the stretching strain is 400%, and after the preset strain is reached, the blank is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with ultrahigh impact strength.
Cutting the stretched sample to prepare a rectangular impact sample strip with a notch of 3 × 80 × 10mm, and then performing impact test to obtain a polylactic acid material sample with the notch impact strength of 127KJ/m2。
Example 10
The polylactic acid raw material dried for 12 hours at the temperature of 60 ℃ is molded into a parison with the thickness of 3 multiplied by 30 multiplied by 100mm in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature by ice water quenching. And (3) stretching the blank on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 60 ℃, the stretching speed is 20mm/min, the stretching strain is 400%, and after the preset strain is reached, the blank is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with ultrahigh impact strength.
Cutting the stretched sample to prepare a rectangular impact sample strip with a notch of 3 × 80 × 10mm, and then performing impact test to obtain the polylactic acid material sample with the notch impact strength of 209KJ/m2。
Example 11
The polylactic acid raw material dried for 12 hours at the temperature of 60 ℃ is molded into a parison with the thickness of 3 multiplied by 30 multiplied by 100mm in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature by ice water quenching. And (3) stretching the blank on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 80 ℃, the stretching speed is 20mm/min, the stretching strain is 400%, and after the preset strain is reached, the blank is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with the stretching strain of 400%.
Cutting the stretched sample to prepare a rectangular impact sample strip with a notch of 3 × 80 × 10mm, and then performing impact test to obtain a polylactic acid material sample with the notch impact strength of 80KJ/m2。
Example 12
The polylactic acid raw material dried for 12 hours at the temperature of 60 ℃ is molded into a parison with the thickness of 3 multiplied by 30 multiplied by 100mm in a film pressing machine, the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature by ice water quenching. And (3) stretching the blank on a temperature-controlled stretching device, wherein the temperature of a stretching chamber is 90 ℃, the stretching speed is 20mm/min, the stretching strain is 400%, and after the preset strain is reached, the blank is cooled and solidified in the air environment at room temperature to obtain a pure polylactic acid transparent material sample with the stretching strain of 400%.
Cutting the stretched sample to prepare a rectangular impact sample strip with a notch of 3 × 80 × 10mm, and then performing impact test to obtain the polylactic acid material sample with the notch impact strength of 13KJ/m2。
Comparative example 1
And (3) molding the polylactic acid dried for 12 hours at the temperature of 60 ℃ into a polylactic acid sheet in a film pressing machine, wherein the molding temperature is 200 ℃, the pressure is 10MPa, the time is 10min, and the sample is cooled to the room temperature through ice water quenching. The samples were cut to produce 1X 4X 50mm dumbbell-shaped tensile bars and 3X 80X 10mm notched rectangular impact bars.
On a Shenzhen Sansi company UTM2502 universal testing machine, pure polylactic acid transparent material samples obtained in the embodiments 1-6 are analyzed according to the standard GB/T1040.3-2006, and a stress-strain curve of the pure polylactic acid transparent material during stretching treatment at 70 ℃ is obtained, as shown in FIG. 1. As can be seen from fig. 1, the stress-strain curve can be divided into three different regions according to different stress responses during stretching: an elastically deformable zone (I), a strain-softened zone (II) and a strain-hardened zone (III). The yield point (strain 100%, example 1) is preceded by an elastic deformation zone (I), the sample exhibits hooke elastic behavior, the strain can be recovered by removing the stress, leaving no permanent deformation; the area behind the yield point is a plastic deformation area, and the sample shows plastic behavior; if the stress is removed, the strain cannot be recovered, leaving a permanent set. In the plastic deformation region, in which the strain is in the range of 100% to 200%, the stress decreases or remains unchanged with the increase of the strain, referred to as strain softening region (II); when the strain is more than 200% (example 2), the stress sharply increases with an increase in strain, which is called a strain hardening zone (III). At 70 ℃, the essentially frozen chain segments in PLA start to move and the stretching of the polymer chains provides the deformation of the material. When the sample is stretched at 70 ℃ to a predetermined tensile strain and then cooled to room temperature or below, the stretched polymer chains are frozen again, and even if the external force is removed, the deformation is not spontaneously recovered. Therefore, according to the stress-strain curve, different tensile strains are selected in the three different areas, tensile sample bars under corresponding strains are prepared, and mechanical property testing and microstructure characterization are carried out on the tensile sample bars.
FIG. 2 is a schematic representation of the sample strips of example 6 after reaching a predetermined strain and being cooled and solidified in an air atmosphere at room temperature.
FIG. 3 is a diagram showing an entire sample taken out of example 6 after stretching and cooling; FIG. 4 is a pictorial representation of a cut-out specimen (top) and a notched impact test specimen (bottom) of the sample removed by cooling after stretching in example 6; as can be seen from fig. 3 and 4, the pure polylactic acid material after the stretching treatment at 70 ℃ in example 6 is colorless and transparent, because the polylactic acid material is subjected to the stretching treatment in a state without adding any auxiliary agent, so that no phase separation occurs in the system, and thus the high transparency is still achieved while the ultra-high impact resistance is obtained. The stretching treatment above the glass transition temperature enables the polylactic acid material to obtain high transparency while obtaining ultrahigh impact resistance, thus greatly widening the applicable field of polylactic acid.
On a Sagsi Feilong series PTM7000 plastic pendulum impact testing machine, pure polylactic acid transparent material samples obtained in examples 1-6 and comparative example 1 are analyzed according to the standard GB/T1843-2008, and a relation graph of the cantilever beam notch impact strength and the strain is obtained. As can be seen from FIG. 5, the pure polylactic acid exhibits brittleness at room temperature and an impact strength of only 2.4KJ/m without being stretched2. When pure polylactic acid is stretched to 100% at 70 ℃ (example 1),the coherent entangled network is just in the initial stage of starting recombination, the degree of orientation is low, and the impact strength value is not obviously changed. When stretched to 200% (example 2), the impact strength values of the samples increased dramatically with further increase in the degree of orientation, from 7.8kJ/m2(example 1) to 73.9KJ/m2And the impact strength is improved to be nearly 31 times of that of the pure polylactic acid before stretching. The impact strength of the treated polylactic acid was increased with further increase in tensile strain, and the impact strength had a maximum value of 231KJ/m at a tensile strain of 400% (example 4)2The toughening effect is very obvious and is 96 times of the impact strength of pure polylactic acid before stretching. After the impact strength of the polylactic acid reaches the maximum value, the degree of order of the oriented fiberized structure in the sample is reduced with further increase of tensile strain, and the impact strength value is slightly reduced.
On a Shenzhen Sansi company UTM2502 universal testing machine, pure polylactic acid transparent material samples obtained in examples 1-5, 7 and 1 are analyzed according to the standard GB/T1040.3-2006, and a stress-strain curve graph of room-temperature secondary stretching is obtained, as shown in FIG. 6. As can be seen from fig. 6, the ultra-high impact strength polylactic acid transparent material obtained after the stretching treatment at 70 ℃ also has a significant change in stretching behavior, and changes from the original brittle fracture to ductile fracture at room temperature, showing typical phenomena of yield, neck and strain hardening. In addition, the thin neck region of the sample strip subjected to secondary stretching at room temperature gradually becomes smaller as the tensile strain increases; when the tensile strain was increased to 700% (example 7), the neck-in phenomenon almost disappeared.
According to the stress-strain graphs of examples 1 to 5, example 7 and comparative example 1 tested on the Shenzhen Mash UTM2502 universal testing machine in the above steps, a relation graph of Young modulus and strain of the secondary stretching at room temperature can be obtained, as shown in FIG. 7. As can be seen from FIG. 7, the Young's modulus in the room temperature secondary stretching of the ultra-high impact strength polylactic acid transparent material obtained after the stretching treatment at 70 ℃ gradually increased with the increase of the tensile strain, and the Young's modulus had a maximum value of 1.96GPa when the material was stretched to a maximum tensile strain of 700% (example 7).
According to the stress-strain graphs of examples 1 to 5, example 7 and comparative example 1 tested on the Shenzhen mitsubishi UTM2502 universal tester in the above steps, a graph of the relationship between the elongation at break and the strain of the secondary stretching at room temperature can be obtained, as shown in FIG. 8. As can be seen from fig. 8, the elongation at break of the polylactic acid transparent material obtained after the stretching treatment at 70 ℃ in the secondary stretching at room temperature gradually decreased with the increase of the tensile strain. Polylactic acid has the maximum elongation at break (90.8%) when the tensile strain of polylactic acid is 100% (example 1); when the tensile strain of the polylactic acid is the greatest (example 7), the elongation at break is the smallest (20.7%), but this value is still greater than the elongation at break of the unstretched polylactic acid bars (5.5%).
According to the stress-strain graphs of examples 1 to 5, example 7 and comparative example 1 tested on the Shenzhen mitsubishi UTM2502 universal tester in the above steps, a fracture strength and strain relationship diagram of the secondary stretching at room temperature can be obtained, as shown in FIG. 9. As can be seen from fig. 9, the breaking strength of the polylactic acid transparent material obtained after the stretching treatment at 70 ℃ in the secondary stretching at room temperature gradually increased with the increase of the tensile strain. When the tensile strain of the polylactic acid was 100% (example 1), the breaking strength of the polylactic acid did not significantly increase compared to that of the non-stretched polylactic acid. The breaking strength of polylactic acid in the secondary stretching at room temperature gradually increased with further increase of the tensile strain, and the breaking strength had a maximum value of 172.2MPa when the tensile strain was 700% at the maximum (example 7).
According to the stress-strain graphs of examples 1 to 5, example 7 and comparative example 1 tested on the Shenzhen mitsubishi UTM2502 universal tester in the above steps, a tensile toughness and strain relationship diagram of the secondary stretching at room temperature can be obtained, as shown in FIG. 10. As can be seen from fig. 10, the tensile toughness of the room-temperature secondary stretching of the polylactic acid transparent material obtained after the stretching treatment at 70 ℃ gradually decreased with the increase of the tensile strain. The polylactic acid has the maximum tensile toughness (40.8 MJ/m) when the tensile strain of the polylactic acid is 100% (example 1)3) (ii) a Tensile toughness when the tensile strain of polylactic acid is maximal (example 7)Minimum (23.6 MJ/m)3) This value is still far greater than the tensile toughness of the unstretched polylactic acid specimen (1.8 MJ/m)3)。
The samples obtained in example 4 and comparative example 1 were analyzed by scanning electron microscopy to obtain a topographic map of brittle sections of the scanning electron microscopy, as shown in fig. 11. As can be seen from fig. 11, in the scanning electron microscope observation of the polylactic acid before the stretching treatment (comparative example 1), the morphology of the brittle fracture surface was isotropic, indicating that the polylactic acid before the stretching treatment was not oriented. After the polylactic acid is stretched (example 4), it is evident in its scanning electron micrograph that the polylactic acid texture is aligned along the stretching direction, resulting in an oriented microstructure.
The samples obtained in examples 2 and 4 and comparative example 1 were analyzed by X-ray diffraction, and their wide-angle X-ray diffraction patterns (the stretching direction is in the horizontal direction) were shown in FIG. 12. As can be seen from FIG. 12, the two-dimensional wide-angle X-ray diffraction pattern of the polylactic acid before the stretching treatment appeared to be an isotropic diffusion ring, indicating that the polylactic acid without stretching treatment (comparative example 1) was amorphous and had no structural orientation. The stretching treatment was carried out at 70 ℃, the intensity of the diffusion ring in the polylactic acid parallel to the stretching direction (the stretching direction is in the horizontal direction) was gradually increased with the increase of the stretching strain, the intensity of the diffusion ring perpendicular to the stretching direction was gradually weakened, and the isotropic diffusion ring was gradually transformed into a pair of wide diffraction arcs parallel to the stretching direction (example 2), indicating that the molecular chains were gradually oriented in the stretching direction during the stretching process, and the degree of orientation was gradually increased. As the tensile strain was further increased, the degree of orientation was further increased, and diffraction spots appeared inside the two pairs of broad diffraction arcs (example 4), which may be caused by diffraction of the highly oriented α' crystal form.
As can be seen by combining the above examples and the attached figures 6 to 10, the breaking strength of the ultra-high impact strength polylactic acid transparent material obtained after the stretching treatment at 70 ℃ is improved from 60MPa to 172MPa, the breaking elongation is improved from 6% to 12% -91%, and the notch impact strength is improved from 2.4KJ/m2Increased to 231KJ/m2The reinforcing and toughening effects are very obvious, and the method ensures thatThe material obtains high transparency.
Claims (10)
1. A preparation method of a polylactic acid transparent material with high impact strength is characterized by comprising the following steps:
s1) forming polylactic acid to obtain a parison;
s2) stretching the parison above the glass transition temperature, cooling and solidifying to obtain the polylactic acid transparent material with high impact strength.
2. The method according to claim 1, wherein the polylactic acid is dried and then molded in step S1).
3. The method according to claim 2, wherein the drying temperature is 20 ℃ to 90 ℃; the drying time is 1-72 h.
4. The method for preparing according to claim 1, wherein the molding method is injection molding or compression molding; the compression molding temperature is 160-250 ℃; the compression molding pressure is 2-12 MPa; the compression molding time is 1-300 min; the temperature of cooling and solidifying is 0-40 ℃.
5. The production method according to claim 1, wherein the temperature of the drawing treatment in the step S2) is 55 ℃ to 100 ℃; the strain of the stretching treatment is 5-1200%.
6. The method according to claim 1, wherein the temperature of the stretching treatment in the step S2) is 60 to 70 ℃; the strain of the stretching treatment is 300-700%.
7. The method according to claim 1, wherein the drawing rate of the drawing treatment in the step S2) is 0.5 to 1000 mm/min.
8. The method according to claim 1, wherein the drawing rate of the drawing treatment in the step S2) is 1 to 50 mm/min.
9. A high impact strength polylactic acid transparent material prepared by the method of any one of claims 1 to 8.
10. The transparent high-impact-strength polylactic acid material according to claim 9, wherein the transparent high-impact-strength polylactic acid material has an impact strength of 127 to 231KJ/m2。
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113370443A (en) * | 2021-06-16 | 2021-09-10 | 中国科学技术大学 | Preparation method of high-impact-strength polypropylene material |
| CN113930065A (en) * | 2021-11-20 | 2022-01-14 | 郑州市彦峰塑料包装有限公司 | High-strength degradable packaging bag and preparation method thereof |
| CN114851427A (en) * | 2022-04-27 | 2022-08-05 | 浙江工业大学 | High-toughness high-transparency heat-resistant polylactic acid material and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010051693A1 (en) * | 1999-12-21 | 2001-12-13 | Seo Kwan Ho | Method of producing a crosslinked polyester formed-goods |
| CN102702705A (en) * | 2012-07-04 | 2012-10-03 | 华东理工大学 | Toughened polylactic acid/polyolefin elastomer composite material and preparation method thereof |
| CN108659491A (en) * | 2018-06-07 | 2018-10-16 | 中国科学院长春应用化学研究所 | A kind of lactic acid composite material of activeness and quietness and preparation method thereof |
| CN109627715A (en) * | 2018-11-22 | 2019-04-16 | 南通大学 | A kind of impact-resisting and heat resistant antibacterial polylactic acid composition and preparation method thereof |
| CN110283343A (en) * | 2019-05-14 | 2019-09-27 | 江苏集萃先进高分子材料研究所有限公司 | A kind of polylactic acid film material of high-strength high-tractility and preparation method thereof |
-
2020
- 2020-06-17 CN CN202010553149.8A patent/CN111673969A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010051693A1 (en) * | 1999-12-21 | 2001-12-13 | Seo Kwan Ho | Method of producing a crosslinked polyester formed-goods |
| CN102702705A (en) * | 2012-07-04 | 2012-10-03 | 华东理工大学 | Toughened polylactic acid/polyolefin elastomer composite material and preparation method thereof |
| CN108659491A (en) * | 2018-06-07 | 2018-10-16 | 中国科学院长春应用化学研究所 | A kind of lactic acid composite material of activeness and quietness and preparation method thereof |
| CN109627715A (en) * | 2018-11-22 | 2019-04-16 | 南通大学 | A kind of impact-resisting and heat resistant antibacterial polylactic acid composition and preparation method thereof |
| CN110283343A (en) * | 2019-05-14 | 2019-09-27 | 江苏集萃先进高分子材料研究所有限公司 | A kind of polylactic acid film material of high-strength high-tractility and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 唐见茂: "《绿色复合材料》", 31 December 2016, 中国铁道出版社 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113370443A (en) * | 2021-06-16 | 2021-09-10 | 中国科学技术大学 | Preparation method of high-impact-strength polypropylene material |
| CN113930065A (en) * | 2021-11-20 | 2022-01-14 | 郑州市彦峰塑料包装有限公司 | High-strength degradable packaging bag and preparation method thereof |
| CN113930065B (en) * | 2021-11-20 | 2022-12-02 | 郑州市彦峰塑料包装有限公司 | High-strength degradable packaging bag and preparation method thereof |
| CN114851427A (en) * | 2022-04-27 | 2022-08-05 | 浙江工业大学 | High-toughness high-transparency heat-resistant polylactic acid material and preparation method thereof |
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