CN113637296B - Preparation method of polylactic acid composite material and preparation method of degradable optical film - Google Patents
Preparation method of polylactic acid composite material and preparation method of degradable optical film Download PDFInfo
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Abstract
The invention provides a preparation method of a polylactic acid composite material and a preparation method of a degradable optical film. The preparation method of the composite material comprises the following steps: adding lactide, plasticizer, auxiliary agent and catalyst into solvent, mixing uniformly, then adding crystalline nanocellulose, dispersing, reacting at first temperature, then heating to second temperature, and continuing to react so as to obtain the polylactic acid composite material. According to the preparation method, the modified polylactic acid composite material is prepared by modifying crystalline nano cellulose, the crystalline nano cellulose has excellent optical property and mechanical property, so that the prepared polylactic acid composite material has a block-like structure, the structure is beneficial to improving the crystallization property of the modified polylactic acid composite material, and the glass transition temperature and Young modulus of the modified polylactic acid composite material are greatly improved under the condition that the degradation property, optical property (transparency and glossiness) of the polylactic acid are not influenced, so that the impact resistance and toughness are improved.
Description
Technical Field
The invention relates to the technical field of polylactic acid materials, in particular to a preparation method of a polylactic acid composite material and a preparation method of a degradable optical film.
Background
The plastic garbage causes great harm to the ecological environment and also causes great threat to human health, and the development of a new generation of sustainable plastic substitute materials is urgent. The act of "limiting or stopping the use of plastic bags and other disposable plastic products" initiated by western european countries, etc., will further drive the market demand for biodegradable plastics. Wherein polylactic acid (PLA) plays an important role, is stable at normal temperature, but can be rapidly degraded in a high-temperature environment, an acid-base environment or a microorganism environment (involving microorganism degradation, hydrolysis, photolysis, radiation degradation, thermal degradation and the like), and has rapid performance degradation and finally becomes CO 2 And water. Factors influencing polylactic acid (PLA) degradation are resin molecular weight, crystalline state, microstructure, ambient temperature and humidity, pH, oxygen, illumination time, and ambient microorganisms. The study of the degradation kinetics of polylactic acid (PLA) in natural environments is very important for use and disposal, and few studies are currently carried out. Degradation of polylactic acid (PLA) is complex and can be roughly divided into two stages: the early stage is physical degradation, breaks the ester chain by the temperature and humidity (water) in the environment, and is cracked into oligomer or monomer, and the later stage is changed into CO by the action of microorganism and enzyme 2 And water. A first partTypically, it begins at the amorphous region and extends to the crystalline region.
In view of the advantages of polylactic acid (PLA), films, foamed materials and containers, such as flexible packages, plastic bottles, cushioning materials, disposable tableware, etc., can be manufactured as packaging materials, mainly films and secondarily containers and sheets from the aspect of morphology. The degradability, barrier property, mechanical property, optical property, antibacterial property, electrical conductivity and piezoelectricity of polylactic acid (PLA) are mostly related to crystallinity, and if the crystallinity of polylactic acid (PLA) is increased, the barrier property, mechanical property are generally increased, but processability, degradability and transparency are generally decreased. Polylactic acid (PLA) is generally applied to the optical film industry, so that the optical film has the problem of degradation performance reduction
Based on the technical drawbacks of current polylactic acid (PLA) materials and optical films, there is a need for improvements.
Disclosure of Invention
In view of the above, the present invention provides a method for preparing a polylactic acid composite material and a method for preparing a degradable optical film, so as to solve or partially solve the technical problems existing in the prior art.
In a first aspect, the invention provides a method for preparing a polylactic acid composite material, comprising the following steps:
adding lactide, plasticizer, auxiliary agent and catalyst into solvent, mixing uniformly, then adding crystalline nanocellulose, dispersing, reacting at first temperature, then heating to second temperature, and continuing to react so as to obtain the polylactic acid composite material.
Preferably, the preparation method of the polylactic acid composite material comprises the steps of adding lactide, plasticizer, auxiliary agent and catalyst into a solvent, uniformly mixing, adding crystalline nanocellulose, dispersing, reacting for 1-3 hours at 100-130 ℃ under the protection of inert gas and under the pressure of 0-100 Pa, then keeping the pressure of 0-50 Pa, heating to 150-180 ℃, and continuing to react for 5-10 hours.
Preferably, in the preparation method of the polylactic acid composite material, adding crystalline nanocellulose further comprises freeze-drying the crystalline nanocellulose, specifically: and drying the crystalline nanocellulose for 10-36 hours at the temperature of-60 to-10 ℃ and under the negative pressure of 20-50 pa.
Preferably, in the preparation method of the polylactic acid composite material, lactide, plasticizer, auxiliary agent and catalyst are added into a solvent, mixed uniformly, then crystalline nanocellulose is added, and dispersed for 10-30 min at 3000-6000 rpm under the protection of inert gas and at the temperature of minus 30-10 ℃.
Preferably, the catalyst comprises one or more of stannous octoate, methyltrichlorotin, stannic chloride, stannous dichloride, dimethylstannous dichloride, phenylstannic trichloride, diphenylstannic dichloride, trimethylstannic chloride, dibutylstannic dichloride, diphenyltin oxide, butylstannic trichloride, tributyltin oxide, trimethyltin, tetraphenyltin, tri-n-butyltin azide, hexan-butyltin, hexamethylditin, hexaphenylditin, tributyltin hydride, tributylvinyltin, trimethyltin bromide, tetraethyltin, triethyltin bromide and tributyltin iodide.
Preferably, in the preparation method of the polylactic acid composite material, the solvent is an alcohol solvent, and the alcohol solvent comprises at least one of methanol, ethanol, propylene glycol, glycerol and ethylene glycol.
Preferably, in the preparation method of the polylactic acid composite material, the polylactic acid composite material is reacted for 1-3 hours at the temperature of 100-130 ℃ under the protection of inert gas and the pressure of 0-100 Pa, then the temperature is raised to 150-180 ℃ under the pressure of 0-50 Pa, and the reaction is continued for 5-10 hours at 150-600 rpm.
Preferably, in the preparation method of the polylactic acid composite material, the mass ratio of the lactide to the plasticizer to the auxiliary agent to the catalyst to the solvent to the crystalline nanocellulose is 100 (1-5)/(1-2)/(80-120)/(1.5-15).
In a second aspect, the present invention also provides a method for preparing a degradable optical film, comprising the steps of:
and extruding, granulating and stretching the polylactic acid composite material prepared by the preparation method to form a film, thus obtaining the degradable optical film.
Preferably, in the preparation method of the degradable optical film, the extrusion temperature is 160-180 ℃.
The invention relates to a preparation method of a polylactic acid composite material
Compared with the prior art, the preparation method has the following beneficial effects:
(1) According to the preparation method of the polylactic acid composite material, the crystalline state nano cellulose is used for modifying and preparing the modified polylactic acid composite material, the crystalline state nano cellulose has excellent optical property and mechanical property, so that the prepared polylactic acid composite material has a block-like structure, the block-like structure is beneficial to improving the crystallization property of the modified polylactic acid composite material, and the glass transition temperature and Young modulus of the modified polylactic acid composite material are greatly improved under the condition that the self degradation property and optical property (transparency and glossiness) of the polylactic acid are not influenced, so that the impact resistance and toughness are improved; the degradation period of the polylactic acid composite material can be regulated and controlled to a certain extent by regulating the proportion of crystalline nanocellulose and lactide;
(2) According to the preparation method of the degradable optical film, the polylactic acid composite material is prepared by extrusion, granulation and stretching, so that the optical film has good impact resistance, toughness, degradation performance and optical performance.
Detailed Description
The following description of the embodiments of the present invention will be made in detail and with reference to the embodiments of the present invention, but it should be apparent that the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, are intended to fall within the scope of the present invention.
The embodiment of the application provides a preparation method of a polylactic acid composite material, which comprises the following steps:
adding lactide, plasticizer, auxiliary agent and catalyst into solvent, mixing uniformly, then adding crystalline nanocellulose, dispersing, reacting at first temperature, then heating to second temperature, and continuing to react so as to obtain the polylactic acid composite material.
It should be noted that, in the embodiment of the present application, the crystalline nanocellulose is obtained from a raw material made of fibers recovered in nature, and specifically, reference is made to a patent with application number CN201310095395.3 for preparing nanocellulose crystals by using kelp residues; or preparing nano-cellulose crystal balls by utilizing onion skins according to the patent with the application number of CN 201310610074.2; or the graded nanocellulose is prepared by utilizing ramie waste according to the patent with the application number of CN 201410000429.0. Lactide is used as a polylactic acid prepolymer, and the plasticizer is specifically phthalate, epoxy acid ester and polyester plasticizer, and a small amount of aliphatic dibasic acid plasticizer can be used in combination in practice; the auxiliary agent is generally selected from organosilicon auxiliary agents or organic siloxane auxiliary agents.
In some embodiments, lactide, plasticizer, auxiliary agent and catalyst are added into solvent, mixed uniformly, then crystalline nanocellulose is added, after dispersion, the mixture is reacted for 1 to 3 hours under the protection of inert gas and under the pressure of 0 to 100Pa and the temperature of 100 to 130 ℃, then the pressure of 0 to 50Pa is kept, the temperature is raised to 150 to 180 ℃, and the reaction is continued for 5 to 10 hours. Specifically, the inert gas may be rare gas or nitrogen, and the solvent and water generated in the reaction may be removed by the reaction at 100-130 ℃.
In some embodiments, adding crystalline nanocellulose further comprises subjecting the crystalline nanocellulose to a lyophilization process, specifically: and drying the crystalline nanocellulose for 10-36 hours at the temperature of-60 to-10 ℃ and under the negative pressure of 20-50 pa.
In some embodiments, lactide, plasticizer, auxiliary agent and catalyst are added into solvent, mixed uniformly, then crystalline nanocellulose is added, and dispersed for 10-30 min under the protection of inert gas at the temperature of-30-10 ℃ and at 3000-6000 rpm.
In some embodiments, the catalyst is an organotin-based catalyst, and in particular, the catalyst comprises one or more of stannous octoate, methyltrichlorotin, stannic chloride, stannous dichloride, dimethylstannous dichloride, phenylstannic trichloride, diphenylstannous dichloride, trimethylstannic chloride, dibutylstannous chloride, diphenylstannic oxide, butylstannic trichloride, tributylstannic oxide, trimethyltin, tetraphenyltin, tri-n-butyltin azide, hexan-butyltin, hexamethylditin, hexaphenylditin, tributyltin hydride, tributylvinyltin, trimethyltin bromide, tetraethyltin, triethyltin bromide, tributyltin iodide.
In some embodiments, the solvent is an alcohol solvent, specifically, the alcohol solvent includes at least one of methanol, ethanol, propylene glycol, glycerol, and ethylene glycol.
In some embodiments, the reaction is performed for 1-3 hours at a temperature of 100-130 ℃ under the protection of inert gas and a pressure of 0-100 Pa, then the temperature is raised to 150-180 ℃ under the pressure of 0-50 Pa, and the reaction is continued for 5-10 hours at 150-600 rpm.
In some embodiments, the mass ratio of the lactide to the plasticizer to the auxiliary agent to the catalyst to the solvent to the crystalline nanocellulose is 100 (1-5): 1-2): 80-120): 1.5-15.
The preparation method of the polylactic acid composite material is modified by modifying crystalline nanocellulose
The crystalline nanocellulose of the polylactic acid composite material has excellent optical performance and mechanical performance, so that the prepared polylactic acid composite material has a block-like structure, the block-like structure is beneficial to improving the crystallization performance of the modified polylactic acid composite material, and the glass transition temperature and Young modulus of the modified polylactic acid composite material are greatly improved without affecting the degradation performance and optical performance (transparency and glossiness) of the polylactic acid composite material, thereby improving the impact resistance and toughness. The degradation period of the polylactic acid composite material can be regulated and controlled to a certain extent by regulating the proportion of crystalline nanocellulose and lactide. Specifically, in the embodiment of the application, the polylactic acid composite material with a similar block structure is a block polymer, and is a linear copolymer formed by alternately polymerizing chain segments with different chemical structures; the block copolymer, as a particular linear copolymer, differs from the blends and graft copolymers in structure and properties in that its glass transition temperature is determined by the polymer at a lower temperature, while its softening point varies with the polymer at a higher temperature, and thus the temperature range in the highly elastic state is wider. The polylactic acid composite material prepared by the method combines the excellent properties of various polymers, so that the polylactic acid composite material has superior performance, and the obtained polylactic acid composite material has controllable molecular weight, narrow molecular weight distribution and designable molecular structure and composition.
Based on the same inventive concept, the embodiment of the application also provides a preparation method of the degradable optical film, which comprises the following steps:
and extruding, granulating and stretching the polylactic acid composite material prepared by the preparation method to form a film, thus obtaining the degradable optical film.
In some embodiments, the extrusion temperature is 160-180 ℃.
It should be noted that, because the optical film in the embodiment of the application is prepared by extruding, granulating and stretching the polylactic acid composite material prepared by the method, the optical film also has higher glass-transition temperature, better shock resistance and toughness, and the crystallinity is improved without changing the optical performance and degradation performance of the optical film; the preparation method of the degradable optical film completely eradicates petroleum-based raw materials, and is environment-friendly.
The preparation method of the polylactic acid composite material and the degradable optical film of the present application is further described in the following specific examples.
Example 1
The embodiment of the application provides a preparation method of a polylactic acid composite material, which comprises the following steps:
s1, under the protection of nitrogen with the vacuum degree of 30Pa, 3 parts of crystalline nanocellulose by weight are dried for 10 hours at the temperature of minus 30 ℃ for standby;
s2, dispersing 100 parts of lactide, 2 parts of plasticizer, 2 parts of auxiliary agent, 1 part of catalyst stannous octoate, 100 parts of absolute ethyl alcohol and the crystalline nanofiber dried in S1 at 3000rpm for 10min under the nitrogen atmosphere, then continuously reacting at 130 ℃ for 2h under the nitrogen pressure of 50pa, then continuously heating to 168 ℃ under the nitrogen pressure of 30pa, and continuously reacting for 6h to obtain the polylactic acid composite material;
wherein the plasticizer comprises a mixture of epoxidized soybean oil and dioctyl adipate in a mass ratio of 3:1;
the auxiliary agent is organosiloxane KH560;
the preparation method of crystalline nanocellulose refers to patent example 1 with application number CN201310095395.3, and specifically comprises the following steps:
a1, steaming and screening: 2g of kelp residue freeze-dried by snow water is crushed and put into a reaction vessel, and 100g of NaCO with the mass percent concentration of 2wt% is added 3 Steaming the water solution in 105 ℃ oil bath for 120min, removing upper layer yellow brown clear liquid, and filtering/washing the lower layer mixture;
a2, pretreatment and photoresist removal: placing the washed and suction-filtered fibers without fluid into a reaction container, adding 100g of NaOH aqueous solution with the mass percent concentration of 2wt%, reacting in an oil bath at the temperature of 120 ℃ for 120min, removing upper yellow-green clear liquid, and suction-filtering/washing the lower mixture;
a3, ultrasonic grinding: placing the fiber obtained by suction filtration into 100g of NaOH aqueous solution with the mass percentage concentration of 2wt%, standing for 12h, placing the mixed solution after standing into an ultrasonic crushing container, performing ultrasonic crushing for 20min, and performing suction filtration/washing again with the power of 500W;
a4, bleaching: the fiber without fluid is placed into a reaction vessel, 3.5g NaOH/7.5mL glacial acetic acid/0.7 g NaClO is added 2 89g of water, the reaction temperature is 80 ℃, the bleaching treatment is carried out for 90min, and then the filtering/washing is carried out;
a5, removing lignin: the fiber obtained by suction filtration and free of fluid was placed in a reaction vessel, and 100g of delignifying agent (Na 3 PO 4 ·12H 2 O/Na 2 SiO 3 ·9H 2 O/NaOH/water 0.8/0.8/2/96.4), and reacting in an oil bath at 100 ℃ for 120min, and suction filtering/washing;
a6, ultrasonic treatment and hydrolysis: uniformly mixing the fibers obtained by suction filtration in water, performing ultrasonic action for 5min with the power of 300W, performing suction filtration again, placing the fibers obtained by suction filtration and without the fluid in a reaction container, adding 100g of sulfuric acid solution with the mass concentration of 64wt%, and stirring in a water bath at 70 ℃ to hydrolyze 4h;
a7, centrifuging/washing: centrifuging/washing with deionized water or distilled water at a centrifugal speed of 10000r/min for 15min, removing supernatant, adding deionized water or distilled water, oscillating to be homogeneous, repeating for 4 times until the pH value is 4.5-7, and obtaining homogeneous solution, namely crystalline nanocellulose.
The embodiment of the application also provides a preparation method of the degradable optical film, which comprises the following steps:
granulating the polylactic acid composite material prepared in the embodiment 1, and biaxially stretching the granulated polylactic acid composite material into a film with the thickness of 100 mu m at 170 ℃ to obtain the degradable optical film.
The degradable optical film prepared in example 1 was tested for properties as follows: the tensile strength is 72.3MPa, the elongation at break is 58%, the bending strength is 102 MPa, the glass transition temperature is 105-115 ℃, the optical transmittance is 89.2%, and the optical haze is 3.3%.
Example 2
The embodiment of the application provides a preparation method of a polylactic acid composite material, which comprises the following steps:
s1, under the protection of nitrogen with the vacuum degree of 30Pa, 9 parts by weight of crystalline nanofiber are dried for 10 hours at the temperature of minus 30 ℃ for standby;
s2, dispersing 100 parts of lactide, 2 parts of tributyl citrate, 3 parts of auxiliary agent (organosiloxane KH 560), 1 part of catalyst stannous octoate, 100 parts of absolute ethyl alcohol and the crystalline nanofiber dried in S1 at 3500rpm for 60min under the nitrogen atmosphere, then continuously reacting at 130 ℃ for 2h under the nitrogen pressure of 50pa, then maintaining the nitrogen pressure of 30pa, heating to 180 ℃, and continuously reacting for 9h to obtain the polylactic acid composite material;
the preparation method of the crystalline nanofiber used in S1 is the same as that of example 1.
The embodiment of the application also provides a preparation method of the degradable optical film, which comprises the following steps:
granulating the polylactic acid composite material prepared in the embodiment 2, and biaxially stretching the granulated polylactic acid composite material into a film with the thickness of 100 mu m at 170 ℃ to obtain the degradable optical film.
The degradable optical film prepared in example 2 was tested for properties as follows: the tensile strength is 75.8MPa, the elongation at break is 65%, the bending strength is 153 MPa, the glass transition temperature is 115-125 ℃, the optical transmittance is 89.5%, and the optical haze is 3.8%.
Comparative example 1
The comparative example provides a method for preparing a polylactic acid material, comprising the following steps:
s1, adding 100 parts by weight of lactide into a reaction kettle, adding 1 part of catalyst stannous octoate, carrying out polymerization reaction at 150 ℃ under the protection of nitrogen, and removing unreacted lactide monomers after polymerization is completed to obtain a polylactic acid material;
the comparative example also provides a method of preparing an optical film comprising the steps of:
granulating the polylactic acid material prepared in the comparative example 1, and biaxially stretching the granulated polylactic acid material into a film with the thickness of 100 mu m at 170 ℃ to obtain the optical film.
The properties of the optical film prepared in comparative example 1 were tested as follows: the tensile strength was 35MPa, the elongation at break was 4%, the flexural strength was 56.5MPa, the glass transition temperature was 62℃and the optical transmittance was 89.8.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (4)
1. The preparation method of the polylactic acid composite material is characterized by comprising the following steps of:
adding lactide, plasticizer, auxiliary agent and catalyst into solvent, mixing uniformly, adding crystalline nano cellulose, dispersing, reacting for 1-3 h under the protection of inert gas and under the pressure of 0-100 Pa at the temperature of 100-130 ℃, then keeping the pressure of 0-50 Pa, heating to 150-180 ℃, and continuing to react for 5-10 h to obtain polylactic acid composite material;
the crystalline state nanocellulose is a nanocellulose crystal prepared by adopting kelp residues;
adding crystalline nanocellulose also comprises freeze-drying the crystalline nanocellulose, specifically: drying the crystalline nanocellulose for 12-36 h at the temperature of-60 to-10 ℃ and the negative pressure of 20-50 pa;
adding lactide, plasticizer, auxiliary agent and catalyst into solvent, mixing uniformly, then adding crystalline nano cellulose, dispersing for 10-30 min at 3000-6000 rpm under the protection of inert gas and at-30-10 ℃;
the catalyst is stannous octoate;
the solvent is ethanol;
the plasticizer is a mixture of epoxidized soybean oil and dioctyl adipate or tributyl citrate with the mass ratio of 3:1;
the auxiliary agent is organosiloxane KH560;
the mass ratio of the lactide to the plasticizer to the auxiliary agent to the catalyst to the solvent to the crystalline nanocellulose is 100 (1-5) (1-2) (80-120) (1.5-15);
the preparation method of the crystalline nanocellulose comprises the following steps:
and (3) steaming and screening: 2g of kelp residue freeze-dried by snow water is crushed and put into a reaction vessel, and 100g of Na with the mass percent concentration of 2wt percent is added 2 CO 3 Steaming the water solution in 105 deg.c oil bath for 120min, eliminating the upper layer yellow brown clear liquid, filtering the lower layer mixture and washing;
pretreatment and photoresist removal: placing the washed and suction-filtered fibers without fluid into a reaction container, adding 100g of NaOH aqueous solution with the mass percent concentration of 2wt%, reacting in an oil bath at the temperature of 120 ℃ for 120min, removing upper yellow-green clear liquid, and suction-filtering and washing a lower mixture;
ultrasonic crushing: placing the fiber obtained by suction filtration into 100g of NaOH aqueous solution with the mass percentage concentration of 2wt%, standing for 12h, placing the mixed solution after standing into an ultrasonic crushing container, ultrasonic crushing for 20min, and performing suction filtration and washing again with the power of 500W;
bleaching: placing the fiber without fluid in a reaction vessel, adding 3.5g NaOH, 7.5mL glacial acetic acid, and 0.7g NaClO 2 89g of water, wherein the reaction temperature is 80 ℃, the bleaching treatment is carried out for 90min, and then the leaching and washing are carried out;
removing lignin: placing the fiber without fluid obtained by suction filtration into a reaction container, adding 100g of delignification reagent, reacting for 120min in an oil bath at 100 ℃, suction filtering and washing; the delignifying agent comprises Na with the mass percentage of 0.8:0.8:2:96.4 3 PO 4 ·12H 2 O、Na 2 SiO 3 ·9H 2 O, naOH and water;
ultrasonic treatment and hydrolysis: uniformly mixing the fibers obtained by suction filtration in water, performing ultrasonic action for 5min with the power of 300W, performing suction filtration again, placing the fibers obtained by suction filtration and without the fluid in a reaction container, adding 100g of sulfuric acid solution with the mass concentration of 64wt%, and stirring and hydrolyzing for 4h in a water bath with the temperature of 70 ℃;
centrifuging and washing: centrifuging/washing with deionized water or distilled water at a centrifugal speed of 10000r/min for 15min, removing supernatant, adding deionized water or distilled water, oscillating to make it homogeneous, repeating for 4 times until pH value is 4.5-7, and obtaining homogeneous solution which is crystalline nanocellulose.
2. The method for preparing a polylactic acid composite material according to claim 1, wherein the reaction is carried out for 1 to 3 hours at a temperature of 100 to 130 ℃ under the protection of inert gas and under a pressure of 0 to 100Pa, then the temperature is raised to 150 to 180 ℃ under the pressure of 0 to 50Pa, and the reaction is continued for 5 to 10 hours at 150 to 600 rpm.
3. A method for preparing a degradable optical film, comprising the steps of:
the polylactic acid composite material prepared by the preparation method of any one of claims 1-2 is extruded, granulated and stretched into a film to obtain the degradable optical film.
4. The method of producing a degradable optical film according to claim 3, wherein the extrusion temperature is 160 to 180 ℃.
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|---|---|---|---|---|
| WO2011097700A1 (en) * | 2010-02-11 | 2011-08-18 | Fpinnovations | Nanocomposite biomaterials of nanocrystalline cellulose (ncc) and polylactic acid (pla) |
| CN101955640B (en) * | 2010-10-15 | 2012-05-09 | 华中科技大学 | Modified biopolymer fiber reinforced polylactic acid composite material and preparation method thereof |
| CN104292439B (en) * | 2014-10-07 | 2016-01-13 | 桂林理工大学 | The preparation method of sisal cellulose nano whisker/poly(lactic acid) Biocomposite material |
| CN107353610A (en) * | 2017-06-20 | 2017-11-17 | 苏州奥宇包装科技有限公司 | A kind of bamboo nano-cellulose whisker reinforcement lactic acid composite material and preparation method thereof |
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