CN116694051B - Low-cost thermal-stability completely biodegradable plastic and preparation method thereof - Google Patents
Low-cost thermal-stability completely biodegradable plastic and preparation method thereof Download PDFInfo
- Publication number
- CN116694051B CN116694051B CN202310793093.7A CN202310793093A CN116694051B CN 116694051 B CN116694051 B CN 116694051B CN 202310793093 A CN202310793093 A CN 202310793093A CN 116694051 B CN116694051 B CN 116694051B
- Authority
- CN
- China
- Prior art keywords
- sections
- powder
- low
- starch
- biodegradable plastic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229920000704 biodegradable plastic Polymers 0.000 title claims abstract description 48
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- 239000000843 powder Substances 0.000 claims abstract description 83
- 229920002472 Starch Polymers 0.000 claims abstract description 67
- 239000008107 starch Substances 0.000 claims abstract description 67
- 235000019698 starch Nutrition 0.000 claims abstract description 67
- 239000004626 polylactic acid Substances 0.000 claims abstract description 58
- 229920000747 poly(lactic acid) Polymers 0.000 claims abstract description 52
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 40
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 32
- 239000002023 wood Substances 0.000 claims abstract description 29
- 229920001397 Poly-beta-hydroxybutyrate Polymers 0.000 claims abstract description 26
- 229920000331 Polyhydroxybutyrate Polymers 0.000 claims abstract description 26
- 239000004014 plasticizer Substances 0.000 claims abstract description 25
- 239000002131 composite material Substances 0.000 claims abstract description 24
- 238000007906 compression Methods 0.000 claims abstract description 18
- 230000006835 compression Effects 0.000 claims abstract description 18
- 238000002156 mixing Methods 0.000 claims abstract description 17
- 239000003822 epoxy resin Substances 0.000 claims abstract description 16
- 229920000647 polyepoxide Polymers 0.000 claims abstract description 16
- 239000002667 nucleating agent Substances 0.000 claims abstract description 14
- 229910021538 borax Inorganic materials 0.000 claims abstract description 10
- 239000004328 sodium tetraborate Substances 0.000 claims abstract description 10
- 235000010339 sodium tetraborate Nutrition 0.000 claims abstract description 10
- 239000002270 dispersing agent Substances 0.000 claims abstract description 5
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 63
- PEDCQBHIVMGVHV-UHFFFAOYSA-N glycerol group Chemical group OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 33
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 27
- 238000001816 cooling Methods 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 17
- 239000010902 straw Substances 0.000 claims description 17
- VBICKXHEKHSIBG-UHFFFAOYSA-N 1-monostearoylglycerol Chemical compound CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO VBICKXHEKHSIBG-UHFFFAOYSA-N 0.000 claims description 15
- 238000001125 extrusion Methods 0.000 claims description 14
- 238000001914 filtration Methods 0.000 claims description 11
- 238000007605 air drying Methods 0.000 claims description 10
- 238000005469 granulation Methods 0.000 claims description 10
- 230000003179 granulation Effects 0.000 claims description 10
- 238000002791 soaking Methods 0.000 claims description 10
- 238000013329 compounding Methods 0.000 claims description 9
- 238000007599 discharging Methods 0.000 claims description 9
- 239000000203 mixture Substances 0.000 claims description 9
- 238000007873 sieving Methods 0.000 claims description 9
- 238000003756 stirring Methods 0.000 claims description 9
- 240000003183 Manihot esculenta Species 0.000 claims description 7
- 235000016735 Manihot esculenta subsp esculenta Nutrition 0.000 claims description 7
- FPAFDBFIGPHWGO-UHFFFAOYSA-N dioxosilane;oxomagnesium;hydrate Chemical compound O.[Mg]=O.[Mg]=O.[Mg]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O FPAFDBFIGPHWGO-UHFFFAOYSA-N 0.000 claims description 7
- 229940075507 glyceryl monostearate Drugs 0.000 claims description 7
- 239000001788 mono and diglycerides of fatty acids Substances 0.000 claims description 7
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 6
- FBPFZTCFMRRESA-FSIIMWSLSA-N D-Glucitol Natural products OC[C@H](O)[C@H](O)[C@@H](O)[C@H](O)CO FBPFZTCFMRRESA-FSIIMWSLSA-N 0.000 claims description 5
- FBPFZTCFMRRESA-JGWLITMVSA-N D-glucitol Chemical compound OC[C@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-JGWLITMVSA-N 0.000 claims description 5
- 229960002920 sorbitol Drugs 0.000 claims description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 claims description 4
- 239000005995 Aluminium silicate Substances 0.000 claims description 3
- 235000021355 Stearic acid Nutrition 0.000 claims description 3
- 235000012211 aluminium silicate Nutrition 0.000 claims description 3
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 3
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 claims description 3
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052901 montmorillonite Inorganic materials 0.000 claims description 3
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 claims description 3
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 239000008117 stearic acid Substances 0.000 claims description 3
- 235000017060 Arachis glabrata Nutrition 0.000 claims description 2
- 244000105624 Arachis hypogaea Species 0.000 claims description 2
- 235000010777 Arachis hypogaea Nutrition 0.000 claims description 2
- 235000018262 Arachis monticola Nutrition 0.000 claims description 2
- 244000060011 Cocos nucifera Species 0.000 claims description 2
- 235000013162 Cocos nucifera Nutrition 0.000 claims description 2
- 229920002261 Corn starch Polymers 0.000 claims description 2
- 240000007594 Oryza sativa Species 0.000 claims description 2
- 235000007164 Oryza sativa Nutrition 0.000 claims description 2
- 240000000111 Saccharum officinarum Species 0.000 claims description 2
- 235000007201 Saccharum officinarum Nutrition 0.000 claims description 2
- 239000008120 corn starch Substances 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 2
- 238000004806 packaging method and process Methods 0.000 claims description 2
- 235000020232 peanut Nutrition 0.000 claims description 2
- 235000009566 rice Nutrition 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 239000002893 slag Substances 0.000 claims description 2
- 239000010456 wollastonite Substances 0.000 claims description 2
- 229910052882 wollastonite Inorganic materials 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 19
- 230000001965 increasing effect Effects 0.000 abstract description 9
- 229920001169 thermoplastic Polymers 0.000 abstract description 5
- 239000004416 thermosoftening plastic Substances 0.000 abstract description 5
- 239000004970 Chain extender Substances 0.000 abstract description 4
- 238000012545 processing Methods 0.000 abstract description 4
- 230000033001 locomotion Effects 0.000 abstract description 2
- 238000010298 pulverizing process Methods 0.000 abstract 1
- 235000011187 glycerol Nutrition 0.000 description 10
- 239000002028 Biomass Substances 0.000 description 9
- 238000002425 crystallisation Methods 0.000 description 8
- 230000008025 crystallization Effects 0.000 description 8
- 239000008187 granular material Substances 0.000 description 8
- 235000013339 cereals Nutrition 0.000 description 7
- 229910052739 hydrogen Inorganic materials 0.000 description 7
- 239000001257 hydrogen Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 239000004629 polybutylene adipate terephthalate Substances 0.000 description 6
- 150000001408 amides Chemical class 0.000 description 5
- UHOVQNZJYSORNB-UHFFFAOYSA-N benzene Substances C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 5
- CDQSJQSWAWPGKG-UHFFFAOYSA-N butane-1,1-diol Chemical compound CCCC(O)O CDQSJQSWAWPGKG-UHFFFAOYSA-N 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 5
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 4
- 229920008262 Thermoplastic starch Polymers 0.000 description 4
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 4
- 229920006238 degradable plastic Polymers 0.000 description 4
- 235000013312 flour Nutrition 0.000 description 4
- 229920003023 plastic Polymers 0.000 description 4
- 239000004033 plastic Substances 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 239000004628 starch-based polymer Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 239000001361 adipic acid Substances 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000006731 degradation reaction Methods 0.000 description 3
- 239000012943 hotmelt Substances 0.000 description 3
- 238000010128 melt processing Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 235000011037 adipic acid Nutrition 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 238000009474 hot melt extrusion Methods 0.000 description 2
- 238000001746 injection moulding Methods 0.000 description 2
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 244000005700 microbiome Species 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- -1 polybutylene adipate terephthalate Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 240000008415 Lactuca sativa Species 0.000 description 1
- 239000004594 Masterbatch (MB) Substances 0.000 description 1
- 244000218514 Opuntia robusta Species 0.000 description 1
- 235000003166 Opuntia robusta Nutrition 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 240000008042 Zea mays Species 0.000 description 1
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 1
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 235000020965 cold beverage Nutrition 0.000 description 1
- 235000005822 corn Nutrition 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 239000002178 crystalline material Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000035622 drinking Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 125000004185 ester group Chemical group 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 230000010006 flight Effects 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 239000004310 lactic acid Substances 0.000 description 1
- 235000014655 lactic acid Nutrition 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000002953 phosphate buffered saline Substances 0.000 description 1
- 239000013502 plastic waste Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 235000012045 salad Nutrition 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/24—Acids; Salts thereof
- C08K3/26—Carbonates; Bicarbonates
- C08K2003/265—Calcium, strontium or barium carbonate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/06—Biodegradable
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/08—Stabilised against heat, light or radiation or oxydation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
- C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/24—Crystallisation aids
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Biological Depolymerization Polymers (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention discloses a low-cost thermal-stability completely biodegradable plastic and a preparation method thereof. The specific technical characteristics are as follows: thermoplastic processing raw starch, a composite plasticizer, water, borax and a guiding agent to obtain pretreated starch; pulverizing wood powder, inorganic powder, nucleating agent, dispersing agent and guiding agent by air flow to obtain pre-dispersed powder; polylactic acid, epoxy resin, pretreated starch and pre-dispersed powder are compressed and extruded by a homodromous parallel double-screw extruder by adopting four sections, five sections and six sections as continuous compression screw elements, so that the low-cost thermal stability complete biodegradable plastic is obtained. The low molecular weight poly-beta-hydroxybutyrate is used for guiding the molecular chain movement of polylactic acid, and epoxy resin is used as a chain extender to promote chain breakage connection, so that the regularity of the polylactic acid is improved, and the crystallinity is increased. Further prolongs the compression time of the screw, enhances the cooperation of a blending system, improves the tensile strength of the modified polylactic acid, improves the heat resistance of the material and meets the use requirement of a terminal product.
Description
Technical Field
The invention belongs to the field of biodegradable plastics, and particularly relates to a low-cost thermal-stability completely biodegradable plastic and a preparation method thereof.
Background
With the rapid increase of global demand for biodegradable plastics, fully biodegradable plastics have come to a new stage of rapid development. Whether it is biodegradability, mechanical use performance, or overall use cost, terminal consumption has put forward brand new requirements on biodegradable plastics. On one hand, the technology is widely developed into high-performance biodegradable plastics, and on the other hand, low-cost biodegradable plastics are continuously sought.
According to the technical requirements of biodegradable plastics, the biodegradable plastics are mainly active groups such as hydroxyl, ester group, carboxyl and the like which are easy to be decomposed by microorganisms as environment-friendly new materials, and can be extremely easily decomposed into water, carbon dioxide and the like by microorganisms in natural environment after the biodegradable plastics are used for a life, so that the biodegradable plastics return to the nature and the pollution to the environment is avoided. Therefore, the full-biodegradable plastic is one of the effective ways to solve the environmental pollution caused by plastic waste.
Currently, the main biodegradable plastics which form the main stream in the market mainly comprise PLA, PBAT, PBS and the like, and the mass production and the application are started. With the large-scale production and application of the full-biodegradable plastic, the consumed monomer raw materials are greatly improved. Such as: the production of polybutylene adipate terephthalate (PBAT) requires the consumption of large amounts of monomer raw materials PTA (terephthalic acid), BDO (butanediol), AA (adipic acid), especially BDO (butanediol), which is not only costly, but also yields are difficult to meet the production requirements of large amounts of polybutylene adipate terephthalate (PBAT). The production of polylactic acid (PLA) requires a large amount of fermented lactic acid, consuming a large amount of corn as raw material. Therefore, the cost of the biodegradable plastic is generally high at present, and the cost reduction is urgent to promote the application of the biodegradable plastic.
In addition, the thermal stability of the full-biodegradable plastic is generally poor, and the full-biodegradable plastic is mainly characterized by poor thermal stability and easy degradation during thermoplastic injection molding; the prepared product has poor heat resistance, is used for cutlery boxes, microwave heating tableware and the like and is easy to soften and deform, and the industrialized application and popularization are affected. Polylactic acid (PLA) which is most commonly used at present has the Vicat softening temperature of only 50-60 ℃ and poor heat resistance, and the main application is limited in low-temperature environments such as cold drink cups, salad trays, fruit trays, stationery products and the like. It is easy to soften for the application of dinner plates, hot drinking cups, electronic products and the like with certain temperature.
In view of the above, in order to advance the application of polylactic acid (PLA), it is the most important technical problem to reduce the cost and improve the heat resistance. Polylactic acid (PLA) has properties that depend largely on crystallization when formed. The crystallinity is high, the arrangement of macromolecular chains is regular, the intermolecular acting force is enhanced, and the tensile strength and heat resistance of polylactic acid (PLA) are high. Polylactic acid (PLA) is a crystalline polymer, but has a very low crystallization rate during thermal processing such as extrusion granulation and injection molding, and thus has low crystallinity and poor heat resistance. Therefore, the use of polylactic acid degradable plastics is comprehensively promoted, and the cost reduction and the crystallinity improvement become key.
The patent with the application number of CN202011181819.4 discloses a production method of bio-based degradable plastics, which comprises the steps of adding plant fibers, natural starch, polylactic acid, polyvinyl alcohol, plasticizer, lubricant and montmorillonite into a high-speed mixer, fully and uniformly mixing, carrying out blending compounding by a double-screw extruder, extruding, cooling and granulating to obtain the bio-based degradable plastic master batch. Although the cost is reduced, the glycerol is directly adopted for plasticizing the starch, and the hydroxyl contained in the glycerol leads to poor water resistance, easy moisture absorption and poor plasticizing stability of the thermoplastic starch, so that the application stability of the thermoplastic starch in the degradable plastics at present is also defective.
A fully biodegradable PLA/PBAT composite material and a method for preparing the same are disclosed in the patent application CN 201210297866.4. The composite material is prepared from the following components in parts by weight: 10-90 parts of polylactic acid, 10-90 parts of poly (butylene terephthalate-co-adipic acid butanediol) ester, 10-80 parts of thermoplastic starch, 0.01-1.5 parts of compatilizer A, 0.1-10 parts of compatilizer B and 1-40 parts of filler. By adding thermoplastic starch, the composite material effectively reduces the manufacturing cost of the product, and simultaneously maintains good mechanical property and flexibility, but the heat resistance is not obviously improved.
As biomass materials, starch, wood powder and the like have great potential in the aspect of being applied to reducing the cost of biological plastics, and have extremely important effects on relieving the shortage of the current raw material supply of the biological degradation plastics and high cost. However, starch and wood powder are crystalline materials with strong polarity, so that the starch and wood powder have strong hydrogen bonds among molecules and in molecules, poor thermoplasticity, difficult processing and poor mechanical properties, and cannot be subjected to melt extrusion. The prior art disclosed the hydrogen bond of starch and wood powder is destroyed by adding more plasticizer, alkali liquor and the like, so that the thermoplastic processability of the starch and wood powder is realized. However, too many hydroxyl groups of the plasticizer cause deterioration of the water resistance, easy moisture absorption, and low strength of the material; and after plasticizing treatment, retrogradation, recrystallization and the like are also carried out, so that hydrogen bonds are recombined to form microcrystalline bundles. These technical drawbacks limit the cost-effective use of starch, wood flour in polylactic acid.
Disclosure of Invention
Starch and wood powder are used as biomass materials, so that the cost is low, the biomass materials are renewable, the biomass materials have remarkable advantages in the aspect of reducing the cost of bioplastic, and the performance of the materials is reduced when the biomass materials are directly used. The invention aims to comprehensively treat starch and wood powder biomass materials, so that the biomass materials are used for polylactic acid to reduce the cost of polylactic acid bioplastic, maintain good service performance and overcome the defect that the biodegradable plastic is not resistant to high temperature. In order to achieve the technical purpose, the invention adopts the following technical scheme:
A preparation method of a low-cost thermal stability completely biodegradable plastic comprises the following specific steps:
(1) Soaking low molecular weight poly-beta-hydroxybutyrate in N, N-dimethylformamide for softening, filtering out the N, N-dimethylformamide, and taking the N, N-dimethylformamide as a guiding agent;
(2) Raw starch, a composite plasticizer, water, borax and a guiding agent according to the mass ratio of 100:2-3:15-20:0.5-0.8:1-2 adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 80-100 ℃, stirring and plasticizing for 30-50min under the rotating speed condition of 50-80rpm, opening an exhaust port to drain steam to reduce the water content to be within 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch;
(3) Wood powder, inorganic powder, nucleating agent, dispersing agent and guiding agent according to the mass ratio of 100:20-30:1-1.5:0.5-1:1-2, uniformly mixing, and crushing and dispersing by an air flow crusher to obtain pre-dispersed powder;
(4) The preparation method comprises the following steps of (1) mixing polylactic acid, epoxy resin, pretreated starch obtained in the step (1) and pre-dispersed powder obtained in the step (2) according to a mass ratio of 100:0.1-0.2:20-30:20-30, and conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 140-150 ℃; two sections: 160-170 ℃; three sections: 170-180 ℃; four sections: 190-200 ℃; five sections: 190-200 ℃; six sections: 180-190 ℃; seven sections: 160-170 ℃; eight sections: 140-150 ℃; nine sections: 140-150 ℃; ten sections: 130-140 ℃; at least two sections of four sections, five sections and six sections of the equidirectional parallel double-screw extruder are provided with continuous compression thread elements; the ratio (L/D) of the length L of the screw rod to the thread outer diameter D is 48 or more; and extruding the strips, and carrying out water cooling, air drying, hob granulation and packaging to obtain the low-cost thermal stability complete biodegradable plastic.
Preferably, the low molecular weight poly-beta-hydroxybutyrate in the step (1) is poly-beta-hydroxybutyrate with a viscosity average molecular weight of 20000-30000 g/mol. After being soaked and softened in N, N-dimethylformamide, the starch and the wood powder are easy to combine, the using amount of a starch plasticizer is reduced, and fusion of the starch, the wood powder and the polylactic acid is ensured. In particular, the low molecular weight poly-beta-hydroxybutyrate is used as a guiding agent, has low viscosity during hot melting, effectively guides the molecular chain movement of polylactic acid and promotes the crystallization of polylactic acid during hot melting processing.
Preferably, the raw starch in the step (2) is one or more of corn starch, tapioca starch and pea starch.
Preferably, in the step (2), the composite plasticizer is glycerol and ethylene glycol according to a mass ratio of 3: 1. The raw starch is a crystalline substance with strong polarity, has strong hydrogen bonds between molecules and in molecules, has poor thermoplasticity, cannot be subjected to melt extrusion, and is difficult to directly replace biological plastics. The composite plasticizer is used for plasticizing, and the composite plasticizer damages hydrogen bonds of starch, so that the starch has thermoplastic processability, and the polylactic acid can ensure biodegradability and obviously reduce cost.
Preferably, the wood powder in the step (3) is one or more of wood powder, rice hull powder, peanut hull powder, straw powder, corncob powder, sugarcane slag powder and coconut shell powder. When preparing the material with higher requirements on the appearance, the wood flour can be soaked in hydrogen peroxide in advance.
Preferably, in the step (3), the inorganic powder is selected from one or more of calcium carbonate, talcum powder, kaolin, wollastonite, barium sulfate, glass powder, silicon dioxide, montmorillonite and aluminum oxide with particle size smaller than 10 μm.
Preferably, the nucleating agent in the step (3) is at least one of N, N' -tricyclohexyl-1, 3, 5-benzene tricarboxamide and D-sorbitol. The nucleating agent can effectively promote the ordered arrangement of chain segments of the polylactic acid during melt extrusion through the action of hydrogen bonds, so that the crystallinity of the polylactic acid is increased.
Preferably, in the step (3), the dispersing agent is one of stearic acid and glyceryl monostearate.
Preferably, the jet mill in the step (3) is a vortex jet mill, and under the action of air suspension and impact, the wood powder is thinned and dispersed with the inorganic powder, so that the aggregation of the wood powder is effectively prevented, the exposure of hydroxyl groups at the interface of the wood powder is promoted, the nucleating agent is pre-dispersed, and the nucleating agent uniformly acts on the polylactic acid during subsequent extrusion. Further preferably, the classification rotational speed of the vortex jet mill is controlled to be 1200rpm or more to obtain a more preferable wood flour D50 particle size of less than 50 μm.
Preferably, the epoxy resin used in the step (4) is E20 epoxy resin. The high-activity epoxy functional group can promote chain breakage connection, increase the regularity of polylactic acid and increase the crystallinity.
The screw combination extruded by the conventional screw is provided with shearing screw thread elements in four sections, five sections and six sections, which is different from the conventional design, at least two sections of the four sections, five sections and six sections of the homodromous parallel double-screw extruder are provided with continuous compression screw thread elements, and the ratio (L/D) of the length L of the screw to the screw thread outer diameter D is 48 or more. By arranging the compression thread element, the shearing thermal degradation of polylactic acid-starch-wood flour is effectively prevented, and by establishing compression pressure, the crosslinking of material hydrogen bonds is promoted, the regularity of the polylactic acid is induced under the action of pressure and a guiding agent, and the crystallinity of the material is increased. It is evident that an L/D greater than 48 ensures a sufficient residence time of the material in the screw for better crystallization.
The invention provides a low-cost thermally stable completely biodegradable plastic prepared by the method. In order to obtain the low-cost and heat-stable full-biodegradable plastic, the starch is subjected to thermal plasticizing treatment, and the low-molecular-weight poly-beta-hydroxybutyrate is further utilized to carry out anti-retrogradation enhancement treatment, so that the low-cost full-biodegradable plastic can be used as a low-cost biomass material to replace polylactic acid so as to reduce the cost; the wood powder and the inorganic powder are used for dispersing the nucleating agent, so that the cost is reduced, the interface hydroxyl of the superfine wood powder is exposed, the nucleating agent can promote the ordered arrangement of chain segments during the hot melt extrusion of polylactic acid, the low molecular weight poly-beta-hydroxybutyrate has low viscosity, and the nucleating agent is used as a guiding agent for guiding the activity of polylactic acid molecular chains and promoting the crystallization of polylactic acid during the hot melt processing, so that the crystallinity of the polylactic acid is increased, and the heat resistance is improved. The epoxy resin is further used as a chain extender in an auxiliary manner, so that broken chain connection can be promoted, the regularity of the polylactic acid is increased, and the crystallinity is increased. In a typical embodiment, the vicat softening point after the polylactic acid is compounded is increased from 55 ℃ to 127 ℃ by using a nucleating agent and a chain extender, and the heat resistance stability is greatly improved.
Compared with the prior art, the low-cost thermal stability completely biodegradable plastic has the outstanding characteristics and beneficial effects that:
1. The invention is used for polylactic acid by plasticizing and enhancing biomass starch, so that the cost can be greatly reduced without affecting the mechanical properties of the material.
2. According to the invention, the wood powder and the inorganic powder are used for dispersing the nucleating agent, so that the cost is reduced, and the nucleating agent can promote the ordered arrangement of chain segments during the hot melt extrusion of the polylactic acid, thereby increasing the crystallinity of the polylactic acid and improving the heat resistance. The addition of the inorganic filler can improve the crystallinity of the polylactic acid and improve the heat resistance.
3. According to the invention, the special modification of starch and wood powder is adopted, the guiding agent is well fused with starch wood powder, and the activity of polylactic acid molecular chains is guided, so that polylactic acid crystallization during hot melt processing is promoted, the screw compression time is further prolonged, polylactic acid crystallization is promoted, the synergy of a blending system is enhanced, the tensile strength of modified polylactic acid is improved, the heat resistance of the material is improved, the use of a terminal product is satisfied, and the production equipment is mature and easy to implement.
Drawings
The invention is further described with reference to the accompanying drawings:
FIG. 1 is a schematic view of the screw flight distribution of a co-rotating parallel twin screw extruder embodying the process of the present invention wherein four, five and six stages are provided with successive compression screw flights.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in connection with the embodiments, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. It should be noted that the terms "water cooling", "air drying for water removal", "hob dicing" are conventional operations of the art; "compression thread element" refers to a low lead thread element having a pitch of 0.4D.
Example 1
(1) Soaking poly-beta-hydroxybutyrate with the viscosity average molecular weight of 20000-30000g/mol in N, N-dimethylformamide for 20min, filtering by press filtration after softening, filtering to remove N, N-dimethylformamide, and taking the softened poly-beta-hydroxybutyrate as a guiding agent for standby;
(2) The pea starch, the composite plasticizer, water, borax and the guiding agent are mixed according to the mass ratio of 100:3:15:0.5:2, adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 100 ℃, stirring and plasticizing for 30min at the rotating speed of 80rpm, then opening an exhaust port to drain steam until the water content is reduced to below 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch granules; the composite plasticizer is glycerol and ethylene glycol according to the mass ratio of 3:1, compounding;
(3) Soaking straw powder into hydrogen peroxide for more than 2 hours, draining, drying, and mixing with 10 mu m calcium carbonate powder, D-sorbitol, glyceryl monostearate and a guiding agent according to a mass ratio of 100:30:1:0.5:2, uniformly mixing, crushing and dispersing by using a jet mill, controlling the grading rotating speed of the vortex jet mill to be more than 1200rpm, and ensuring that the grain diameter of the straw powder D50 is less than 50 mu m to obtain pre-dispersed powder;
(4) The polylactic acid, the E20 epoxy resin, the pretreated starch obtained in the step (1) and the pre-dispersed powder obtained in the step (2) are mixed according to the mass ratio of 100:0.2:30:30, conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 150 ℃; two sections: 160 ℃; three sections: 170 ℃; four sections: 190 ℃; five sections: 190 ℃; six sections: 190 ℃; seven sections: 170 ℃; eight sections: 150 ℃; nine sections: 140 ℃; ten sections: 130 ℃; four, five and six sections of the equidirectional parallel double-screw extruder are provided with continuous compression screw elements (shown in figure 1); the ratio (L/D) of the length L of the screw to the thread outer diameter D is 48; and extruding the strips, and performing water cooling, air drying, water removal and hob granulation to obtain the low-cost thermal stability complete biodegradable plastic.
Through advanced treatment of starch and straw powder, complete alloy is formed with polylactic acid, the crystallinity of the polylactic acid is improved, and the prepared granules have transparent appearance.
Example 2
(1) Soaking poly-beta-hydroxybutyrate with the viscosity average molecular weight of 20000-30000g/mol in N, N-dimethylformamide for 20min, filtering out the N, N-dimethylformamide, and softening the poly-beta-hydroxybutyrate to serve as a guiding agent for standby;
(2) Tapioca starch, a composite plasticizer, water, borax and a guiding agent according to the mass ratio of 100:2:15:0.5:2, adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 100 ℃, stirring and plasticizing for 30min at the rotating speed of 80rpm, then opening an exhaust port to drain steam until the water content is reduced to below 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch granules; the composite plasticizer is glycerol and ethylene glycol according to the mass ratio of 3:1, compounding;
(3) Straw powder, talcum powder with the diameter of 10 mu m, N' -tricyclohexyl-1, 3, 5-benzene trimethyl amide and glyceryl monostearate and a guiding agent are mixed according to the mass ratio of 100:30:1:0.5:2, uniformly mixing, crushing and dispersing by using a jet mill, controlling the grading rotating speed of the vortex jet mill to be more than 1200rpm, and ensuring that the grain diameter of the straw powder D50 is less than 50 mu m to obtain pre-dispersed powder;
(4) The polylactic acid, the E20 epoxy resin, the pretreated starch obtained in the step (1) and the pre-dispersed powder obtained in the step (2) are mixed according to the mass ratio of 100:0.2:30:30, conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 150 ℃; two sections: 160 ℃; three sections: 170 ℃; four sections: 190 ℃; five sections: 190 ℃; six sections: 190 ℃; seven sections: 170 ℃; eight sections: 150 ℃; nine sections: 140 ℃; ten sections: 130 ℃; four sections, five sections and six sections of the equidirectional parallel double-screw extruder are provided with continuous compression thread elements; the ratio (L/D) of the length L of the screw to the thread outer diameter D is 48; and extruding the strips, and performing water cooling, air drying, water removal and hob granulation to obtain the low-cost thermal stability complete biodegradable plastic.
Example 3
(1) Soaking poly-beta-hydroxybutyrate with the viscosity average molecular weight of 20000-30000g/mol in N, N-dimethylformamide for 20min, filtering out the N, N-dimethylformamide, and softening the poly-beta-hydroxybutyrate to serve as a guiding agent for standby;
(2) The pea starch, the composite plasticizer, water, borax and the guiding agent are mixed according to the mass ratio of 100:3:15:0.5:2, adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 100 ℃, stirring and plasticizing for 30min at the rotating speed of 80rpm, then opening an exhaust port to drain steam until the water content is reduced to below 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch granules; the composite plasticizer is glycerol and ethylene glycol according to the mass ratio of 3:1, compounding;
(3) Mixing straw powder with 10 mu m kaolin, D-sorbitol, stearic acid and a guiding agent according to a mass ratio of 100:30:1:0.5:2, uniformly mixing, crushing and dispersing by using a jet mill, controlling the grading rotating speed of the vortex jet mill to be more than 1200rpm, and ensuring that the grain diameter of the straw powder D50 is less than 50 mu m to obtain pre-dispersed powder;
(4) The polylactic acid, the E20 epoxy resin, the pretreated starch obtained in the step (1) and the pre-dispersed powder obtained in the step (2) are mixed according to the mass ratio of 100:0.2:30:30, conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 150 ℃; two sections: 160 ℃; three sections: 170 ℃; four sections: 190 ℃; five sections: 190 ℃; six sections: 190 ℃; seven sections: 170 ℃; eight sections: 150 ℃; nine sections: 140 ℃; ten sections: 130 ℃; four sections, five sections and six sections of the equidirectional parallel double-screw extruder are provided with continuous compression thread elements; the ratio (L/D) of the length L of the screw to the thread outer diameter D is 48; and extruding the strips, and performing water cooling, air drying, water removal and hob granulation to obtain the low-cost thermal stability complete biodegradable plastic.
Example 4
(1) Soaking poly-beta-hydroxybutyrate with the viscosity average molecular weight of 20000-30000g/mol in N, N-dimethylformamide for 20min, filtering out the N, N-dimethylformamide, and softening the poly-beta-hydroxybutyrate to serve as a guiding agent for standby;
(2) Tapioca starch, a composite plasticizer, water, borax and a guiding agent according to the mass ratio of 100:2:15:0.5:2, adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 100 ℃, stirring and plasticizing for 30min at the rotating speed of 80rpm, then opening an exhaust port to drain steam until the water content is reduced to below 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch granules; the composite plasticizer is glycerol and ethylene glycol according to the mass ratio of 3:1, compounding;
(3) Straw powder, talcum powder with the diameter of 10 mu m, N' -tricyclohexyl-1, 3, 5-benzene trimethyl amide, D-sorbitol, glycerin monostearate and a guiding agent are mixed according to the mass ratio of 100:30:0.5:0.5:0.5:2, uniformly mixing, crushing and dispersing by using a jet mill, controlling the grading rotating speed of the vortex jet mill to be more than 1200rpm, and ensuring that the grain diameter of the straw powder D50 is less than 50 mu m to obtain pre-dispersed powder;
(4) The polylactic acid, the E20 epoxy resin, the pretreated starch obtained in the step (1) and the pre-dispersed powder obtained in the step (2) are mixed according to the mass ratio of 100:0.2:30:30, conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 150 ℃; two sections: 160 ℃; three sections: 170 ℃; four sections: 190 ℃; five sections: 190 ℃; six sections: 190 ℃; seven sections: 170 ℃; eight sections: 150 ℃; nine sections: 140 ℃; ten sections: 130 ℃; four sections, five sections and six sections of the equidirectional parallel double-screw extruder are provided with continuous compression thread elements; the ratio (L/D) of the length L of the screw to the thread outer diameter D is 48; and extruding the strips, and performing water cooling, air drying, water removal and hob granulation to obtain the low-cost thermal stability complete biodegradable plastic.
Comparative example 1
(1) Soaking poly-beta-hydroxybutyrate with viscosity average molecular weight of 100000g/mol in N, N-dimethylformamide for 20min, filtering out the N, N-dimethylformamide, and softening the poly-beta-hydroxybutyrate to serve as a guiding agent for standby;
(2) Tapioca starch, a composite plasticizer, water, borax and poly-beta-hydroxybutyrate according to the mass ratio of 100:2:15:0.5:2, adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 100 ℃, stirring and plasticizing for 30min at the rotating speed of 80rpm, then opening an exhaust port to drain steam until the water content is reduced to below 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch granules; the composite plasticizer is glycerol and ethylene glycol according to the mass ratio of 3:1, compounding;
(3) Straw powder, talcum powder with the diameter of 10 mu m, N' -tricyclohexyl-1, 3, 5-benzene trimethyl amide and glyceryl monostearate and a guiding agent are mixed according to the mass ratio of 100:30:1:0.5:2, uniformly mixing, crushing and dispersing by using a jet mill, controlling the grading rotating speed of the vortex jet mill to be more than 1200rpm, and ensuring that the grain diameter of the straw powder D50 is less than 50 mu m to obtain pre-dispersed powder;
(4) The polylactic acid, the E20 epoxy resin, the pretreated starch obtained in the step (1) and the pre-dispersed powder obtained in the step (2) are mixed according to the mass ratio of 100:0.2:30:30, conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 150 ℃; two sections: 160 ℃; three sections: 170 ℃; four sections: 190 ℃; five sections: 190 ℃; six sections: 190 ℃; seven sections: 170 ℃; eight sections: 150 ℃; nine sections: 140 ℃; ten sections: 130 ℃; four sections, five sections and six sections of the equidirectional parallel double-screw extruder are provided with continuous compression thread elements; the ratio (L/D) of the length L of the screw to the thread outer diameter D is 48; and extruding the strips, and performing water cooling, air drying, water removal and hob granulation to obtain the low-cost thermal stability complete biodegradable plastic.
Comparative example 2
(1) Soaking poly-beta-hydroxybutyrate with the viscosity average molecular weight of 20000-30000g/mol in N, N-dimethylformamide for 20min, filtering out the N, N-dimethylformamide, and softening the poly-beta-hydroxybutyrate to serve as a guiding agent for standby;
(2) Tapioca starch, a composite plasticizer, water, borax and a guiding agent according to the mass ratio of 100:2:15:0.5:2, adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 100 ℃, stirring and plasticizing for 30min at the rotating speed of 80rpm, then opening an exhaust port to drain steam until the water content is reduced to below 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch granules; the composite plasticizer is glycerol and ethylene glycol according to the mass ratio of 3:1, compounding;
(3) Straw powder, talcum powder with the diameter of 10 mu m, N' -tricyclohexyl-1, 3, 5-benzene trimethyl amide and glyceryl monostearate and a guiding agent are mixed according to the mass ratio of 100:30:1:0.5:2, uniformly mixing, crushing and dispersing by using a jet mill, controlling the grading rotating speed of the vortex jet mill to be more than 1200rpm, and ensuring that the grain diameter of the straw powder D50 is less than 50 mu m to obtain pre-dispersed powder;
(4) Polylactic acid, the pretreated starch obtained in the step (1) and the pre-dispersed powder obtained in the step (2) are mixed according to the mass ratio of 100:30:30, conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 150 ℃; two sections: 160 ℃; three sections: 170 ℃; four sections: 190 ℃; five sections: 190 ℃; six sections: 190 ℃; seven sections: 170 ℃; eight sections: 150 ℃; nine sections: 140 ℃; ten sections: 130 ℃; four sections, five sections and six sections of the equidirectional parallel double-screw extruder are provided with continuous compression thread elements; the ratio (L/D) of the length L of the screw to the thread outer diameter D is 48; and extruding the strips, and performing water cooling, air drying, water removal and hob granulation to obtain the low-cost thermal stability complete biodegradable plastic.
Comparative example 3
(1) Soaking poly-beta-hydroxybutyrate with the viscosity average molecular weight of 20000-30000g/mol in N, N-dimethylformamide for 20min, filtering out the N, N-dimethylformamide, and softening the poly-beta-hydroxybutyrate to serve as a guiding agent for standby;
(2) Tapioca starch, a composite plasticizer, water, borax and a guiding agent according to the mass ratio of 100:2:15:0.5:2, adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 100 ℃, stirring and plasticizing for 30min at the rotating speed of 80rpm, then opening an exhaust port to drain steam until the water content is reduced to below 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch granules; the composite plasticizer is glycerol and ethylene glycol according to the mass ratio of 3:1, compounding;
(3) Straw powder, talcum powder with the diameter of 10 mu m, N' -tricyclohexyl-1, 3, 5-benzene trimethyl amide and glyceryl monostearate and a guiding agent are mixed according to the mass ratio of 100:30:1:0.5:2, uniformly mixing, crushing and dispersing by using a jet mill, controlling the grading rotating speed of the vortex jet mill to be more than 1200rpm, and ensuring that the grain diameter of the straw powder D50 is less than 50 mu m to obtain pre-dispersed powder;
(4) The polylactic acid, the E20 epoxy resin, the pretreated starch obtained in the step (1) and the pre-dispersed powder obtained in the step (2) are mixed according to the mass ratio of 100:0.2:30:30, conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 150 ℃; two sections: 160 ℃; three sections: 170 ℃; four sections: 190 ℃; five sections: 190 ℃; six sections: 190 ℃; seven sections: 170 ℃; eight sections: 150 ℃; nine sections: 140 ℃; ten sections: 130 ℃; four sections of the equidirectional parallel double-screw extruder are provided with continuous compression thread elements; the ratio (L/D) of the length L of the screw to the thread outer diameter D is 48; and extruding the strips, and performing water cooling, air drying, water removal and hob granulation to obtain the low-cost thermal stability complete biodegradable plastic.
The fully biodegradable plastic was evaluated for performance analysis as follows, and the test bars were injection molded standard bars.
1. Testing mechanical properties:
With reference to the measurement of the tensile properties of GB/T1040 plastics, the mechanical properties were tested, with a tensile rate of 5mm/min.
The bending strength was tested with reference to GB/T9341 at a test rate of 2mm/min. As shown in table 1.
2. Heat resistance test (vicat softening point):
The Vicat softening point of the materials is tested with reference to GB/T1633 determination of the softening temperature (VST) of thermoplastics. As shown in table 1.
Table 1:
obviously, the invention guides the molecular chain activity of polylactic acid by utilizing low molecular weight poly-beta-hydroxybutyrate to promote the crystallization of polylactic acid during hot melt processing, and uses epoxy resin as a chain extender to promote chain breakage connection, thereby increasing the regularity and crystallinity of polylactic acid. In the process, the polylactic acid is crystallized by continuous compression, so that the alloy of the polylactic acid, starch and wood powder maintains high strength and heat resistance, and the cost is reduced and the performance is improved.
The foregoing detailed description is given by way of example only and is not to be construed as limiting the scope of the invention, as it is for the person skilled in the art to better understand the present patent; any equivalent alterations or modifications made in accordance with the spirit of the disclosure fall within the scope of the disclosure.
Claims (8)
1. The preparation method of the low-cost heat-stability completely biodegradable plastic is characterized by comprising the following steps of:
(1) Soaking low molecular weight poly-beta-hydroxybutyrate in N, N-dimethylformamide for softening, filtering out the N, N-dimethylformamide, and taking the N, N-dimethylformamide as a guiding agent; the low molecular weight poly-beta-hydroxybutyrate is selected from poly-beta-hydroxybutyrate with viscosity average molecular weight of 20000-30000 g/mol;
(2) Raw starch, a composite plasticizer, water, borax and a guiding agent according to the mass ratio of 100:2-3:15-20:0.5-0.8:1-2 adding the starch into a high-speed mixer, setting the temperature of the high-speed mixer to be 80-100 ℃, stirring and plasticizing for 30-50min under the rotating speed condition of 50-80rpm, opening an exhaust port to drain steam to reduce the water content to be within 10%, and then discharging, cooling, crushing and sieving to obtain pretreated starch; the composite plasticizer is glycerol and ethylene glycol according to the mass ratio of 3:1, compounding;
(3) Wood powder, inorganic powder, nucleating agent, dispersing agent and guiding agent according to the mass ratio of 100:20-30:1-1.5:0.5-1:1-2, uniformly mixing, and crushing and dispersing by an air flow crusher to obtain pre-dispersed powder;
(4) The preparation method comprises the following steps of (1) mixing polylactic acid, epoxy resin, pretreated starch obtained in the step (1) and pre-dispersed powder obtained in the step (2) according to a mass ratio of 100:0.1-0.2:20-30:20-30, and conveying the mixture to a homodromous parallel double-screw extruder, and controlling the extrusion temperature of the homodromous parallel double-screw extruder to be: a section of: 140-150 ℃; two sections: 160-170 ℃; three sections: 170-180 ℃; four sections: 190-200 ℃; five sections: 190-200 ℃; six sections: 180-190 ℃; seven sections: 160-170 ℃; eight sections: 140-150 ℃; nine sections: 140-150 ℃; ten sections: 130-140 ℃; at least two sections of four sections, five sections and six sections of the equidirectional parallel double-screw extruder are provided with continuous compression thread elements; the ratio (L/D) of the length L of the screw rod to the thread outer diameter D is 48 or more; and extruding the strips, and carrying out water cooling, air drying, hob granulation and packaging to obtain the low-cost thermal stability complete biodegradable plastic.
2. The method for preparing the low-cost thermally stable completely biodegradable plastic according to claim 1, wherein the method comprises the steps of: the raw starch in the step (2) is one or more of corn starch, tapioca starch and pea starch.
3. The method for preparing the low-cost thermally stable completely biodegradable plastic according to claim 1, wherein the method comprises the steps of: the wood powder in the step (3) is one or more of wood powder, rice hull powder, peanut shell powder, straw powder, corncob powder, sugarcane slag powder and coconut shell powder; the inorganic powder is one or more of calcium carbonate, talcum powder, kaolin, wollastonite, barium sulfate, glass powder, silicon dioxide, montmorillonite and aluminum oxide with the particle size smaller than 10 mu m.
4. The method for preparing the low-cost thermally stable completely biodegradable plastic according to claim 1, wherein the method comprises the steps of: the nucleating agent in the step (3) is at least one of N, N' -tricyclohexyl-1, 3, 5-benzene tricarboxamide and D-sorbitol.
5. The method for preparing the low-cost thermally stable completely biodegradable plastic according to claim 1, wherein the method comprises the steps of: and (3) selecting one of stearic acid and glyceryl monostearate as the dispersing agent.
6. The method for preparing the low-cost thermally stable completely biodegradable plastic according to claim 1, wherein the method comprises the steps of: the jet mill in the step (3) is a vortex jet mill; further, the classification rotational speed of the vortex jet mill is controlled to be more than 1200 rpm.
7. The method for preparing the low-cost thermally stable completely biodegradable plastic according to claim 1, wherein the method comprises the steps of: and E20 epoxy resin is used as the epoxy resin in the step (4).
8. A low-cost thermal stability completely biodegradable plastic is characterized in that: prepared by the method of any one of claims 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310793093.7A CN116694051B (en) | 2023-06-30 | 2023-06-30 | Low-cost thermal-stability completely biodegradable plastic and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310793093.7A CN116694051B (en) | 2023-06-30 | 2023-06-30 | Low-cost thermal-stability completely biodegradable plastic and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116694051A CN116694051A (en) | 2023-09-05 |
| CN116694051B true CN116694051B (en) | 2024-08-06 |
Family
ID=87823892
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310793093.7A Active CN116694051B (en) | 2023-06-30 | 2023-06-30 | Low-cost thermal-stability completely biodegradable plastic and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116694051B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102863654A (en) * | 2012-10-11 | 2013-01-09 | 武汉华丽环保科技有限公司 | Starch and polylactic acid composite material and preparation method thereof |
| CN107151427A (en) * | 2016-03-02 | 2017-09-12 | 黑龙江鑫达企业集团有限公司 | A kind of biodegradable toughness reinforcing heat-proof polylactic acid modified resin and preparation method thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1914015A (en) * | 2004-01-29 | 2007-02-14 | 伊斯曼化学公司 | Compression-induced crystallization of crystallizable polymers |
| CN1315928C (en) * | 2005-07-21 | 2007-05-16 | 同济大学 | Aliphatic polyester/starch/clay ternary degradable resin and production thereof |
| BRPI0600683A (en) * | 2006-02-24 | 2007-11-20 | Phb Ind Sa | environmentally degradable polymer composition and its process of obtaining |
-
2023
- 2023-06-30 CN CN202310793093.7A patent/CN116694051B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102863654A (en) * | 2012-10-11 | 2013-01-09 | 武汉华丽环保科技有限公司 | Starch and polylactic acid composite material and preparation method thereof |
| CN107151427A (en) * | 2016-03-02 | 2017-09-12 | 黑龙江鑫达企业集团有限公司 | A kind of biodegradable toughness reinforcing heat-proof polylactic acid modified resin and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116694051A (en) | 2023-09-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103265716B (en) | Straw fiber/PBS(poly butylene succinate)/PBAT (propylene adipate and polybutylene terephthalate) composite and preparation method thereof | |
| CN112940471A (en) | Degradable plastic, preparation method thereof and disposable product | |
| CN102070891B (en) | Polyester composite filled with lignin and preparation method thereof | |
| CN112048162B (en) | Full-biodegradable modified plastic for plastic-uptake thin-wall products and preparation method thereof | |
| CN108929527B (en) | PBAT/modified starch full-biodegradable film with high ductility and high barrier property as well as preparation method and application thereof | |
| CN106916424A (en) | A kind of high-tenacity heat-resistant type full-biodegradable polylactic acid material and preparation method thereof | |
| CN101591467A (en) | A kind of polylactic wood/plastic composite material and preparation method thereof | |
| CN112080115B (en) | High-toughness polylactic acid composite material for environment-friendly tableware and preparation method thereof | |
| CN105504363A (en) | Starch and plant fiber composite biodegradable polyester film-blowing grade resin and preparation method | |
| CN112778723A (en) | Starch-based degradable desorption tube material and preparation method thereof | |
| CN107216623B (en) | Biodegradable polylactic acid composite material, preparation method and application thereof | |
| CN112708246B (en) | Multi-component biodegradable mulching film and preparation method thereof | |
| CN113201172A (en) | Coffee grounds degradable cold drink straw and preparation method thereof | |
| CN103265669B (en) | Method for preparing special compatibilizer for straw fiber/ poly(butylene succinate) (PBS) composite material and application | |
| CN112210196A (en) | Biodegradable polylactic acid product and preparation method thereof | |
| CN111849130A (en) | Full-biodegradable plastic film and preparation method thereof | |
| CN102250389A (en) | Biodegradable polymer material compatibilized and blended by lignocellulose and preparation method thereof | |
| CN116694051B (en) | Low-cost thermal-stability completely biodegradable plastic and preparation method thereof | |
| CN112029246B (en) | Plant fiber-containing polylactic acid modified material and preparation method thereof | |
| CN112625304B (en) | High-starch-filled PBAT material and preparation method thereof | |
| CN101851406A (en) | Completely degradable plastic film and production process thereof | |
| CN114106534A (en) | PLA/PHA heat-resistant straw and preparation method thereof | |
| CN112251012A (en) | Method for preparing degradable plastic master batch by soluble salt-assisted plasticizing amylose | |
| CN112094487A (en) | Easily-cleaned high-temperature-resistant polylactic acid composite material for environment-friendly tableware | |
| CN112266583A (en) | Preparation method of high-strength low-cost full-biodegradable material and product thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |