CN107793708B - Thermoplastic cellulose and aliphatic aromatic copolyester blend and preparation method thereof - Google Patents
Thermoplastic cellulose and aliphatic aromatic copolyester blend and preparation method thereof Download PDFInfo
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- CN107793708B CN107793708B CN201610803931.4A CN201610803931A CN107793708B CN 107793708 B CN107793708 B CN 107793708B CN 201610803931 A CN201610803931 A CN 201610803931A CN 107793708 B CN107793708 B CN 107793708B
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- 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
- C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
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- C—CHEMISTRY; METALLURGY
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
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- C08L2203/16—Applications used for films
Abstract
The invention relates to a blend of thermoplastic cellulose and aliphatic aromatic copolyester, which mainly solves the technical problems of high viscosity and limited processing technology in the low-temperature processing process of the thermoplastic cellulose in the prior art. The invention adopts a blend consisting of 20 to 80 mass percent of thermoplastic cellulose and 80 to 20 mass percent of aliphatic aromatic copolyester, the blend is prepared by a continuous melt extrusion blending method, the melt viscosity of the blend is at least about 20 percent lower than the blending addition theoretical value of two starting materials under the condition of low shear rate; the technical proposal that the theoretical value of blending addition of the two starting materials is at least 20 percent lower under the condition of high shear rate better solves the problem, and because the melt viscosity of the blend is low, the blend can save more energy in the processing process and can be applied to the thermoplastic processing technology of biodegradable materials.
Description
Technical Field
The invention belongs to the field of blend materials of thermoplastic cellulose and aliphatic aromatic copolyester, particularly relates to a blend of thermoplastic cellulose and aliphatic aromatic copolyester with special rheological property, and also relates to a method for preparing the blend of thermoplastic cellulose and aliphatic aromatic copolyester with special rheological property.
Technical Field
Cellulose is the most abundant organic polymer on earth and also the most renewable biomass material every year. Cellulose is the structural material in the cell wall of green plants, woody plants contain about 30-40% cellulose, and cotton fibers contain about 90% cellulose. The main industrial uses of cellulose are paper and board, with a small amount of cellulose being used for the preparation of regenerated cellulose such as cellulophenol (Cellophane), viscose (Rayon) and some cellulose derivatives.
Since cellulose is a natural polymer that plants convert carbon dioxide and water in the atmosphere into carbon dioxide and water through photosynthesis, carbon elements in cellulose belong to recently fixed carbon and are different from carbon elements fixed millions of years ago in fossil fuels such as petroleum or coal and petrochemical products thereof, and carbon elements fixed at different periods can pass through14Isotope of CAnd (5) detecting by a calibration method. Due to the differences, the bio-based polymer material prepared based on the biomass raw material has the advantage of low carbon of the raw material compared with the petroleum-based polymer material, and the green low-carbon polymer material can be produced by adopting the production process with low energy consumption and low carbon emission. In view of such considerations, natural polymers including cellulose, hemicellulose, lignin, starch, chitin, and the like, and derivatives and materials thereof have been increasingly focused and researched globally to develop high-quality green, low-carbon, and environmentally-friendly materials. The wide application of the green low-carbon material confirmed by Life Cycle Assessment (Life Cycle Assessment) is helpful for supporting green production and green Life style, and contributes to reducing the content of greenhouse effect gases (carbon dioxide and the like) in the atmosphere and relieving global climate change.
Although cellulose has the advantage of low carbon in raw materials, the amount of cellulose used as a plastic material is small, since cellulose has a thermal decomposition temperature lower than its melting point and does not have thermoplastic properties. In order to overcome the defect of cellulose, researchers have developed regenerated cellulose produced by a solution method, i.e. cellulose or a cellulose derivative is dissolved in a solvent, and is processed and formed by the solution to be prepared into a film or is converted into cellulose after spinning, and viscose in the textile industry is prepared by the method.
In addition, the cellulose derivative has a low melting or plasticizing temperature after sufficient chemical transformation of the three hydroxyl groups on each repeating glucose unit, can be subjected to limited thermoplastic processing to form thermoplastic cellulose, and the materials comprise cellulose ester and cellulose ether with a certain degree of substitution. Because the yield and the product variety of the cellulose derivatives are limited, the viscosity of the industrialized products is higher, and is particularly obvious at lower processing temperature, and the products are not suitable for processing methods needing low melt viscosity, such as spinning, injection molding and the like; cellulose esters and cellulose ethers are currently used in large part as additives in the field of coatings or adhesives [ gayal, manoming, biomass materials and applications, 2008 ]. Therefore, from the viewpoint of processing applications, there is a technical need to develop a thermoplastic cellulose derivative having a low viscosity and good processability to meet the market demand of the relevant raw materials.
Until now, no document has reported the specific rheological behavior of blends of thermoplastic cellulose and aliphatic aromatic co-polyester, and no method has been provided in the prior art to effectively reduce the melt viscosity of blends of thermoplastic cellulose and aliphatic aromatic co-polyester, which limits the application of such blends.
The invention discloses a continuous melt extrusion method for effectively reducing the melt viscosity of a blend of thermoplastic cellulose and aliphatic aromatic copolyester, discovers unexpected phenomena and results, and discloses a blend composition with special rheological properties.
Disclosure of Invention
One of the technical problems solved by the invention is that the melt viscosity of the blend of the thermoplastic cellulose and the aliphatic aromatic copolyester is too high in the prior art and cannot be applied to the field needing low melt viscosity, and the invention provides a blend material of the thermoplastic cellulose and the aliphatic aromatic copolyester with special rheological property, which can effectively reduce the viscosity of the blend to be lower than the theoretical viscosity of the blend of the thermoplastic cellulose and the starting raw materials of the aliphatic aromatic copolyester unexpectedly; the blend has the processing performances of film making, injection molding, spinning and the like at a lower temperature, is superior to the similar blend in the prior art, and can save more energy in the processing process due to low melt viscosity of the blend.
The second technical problem to be solved by the invention is to provide a method for preparing a thermoplastic cellulose and aliphatic aromatic copolyester blend material with special rheological properties, wherein the melt viscosity of the blend obtained by the method is low shear rate (100 s)-1) At least about 20% lower than the theoretical value of the additive blend of the two starting materials under the conditions; at high shear rates (1000 or 1363 s)-1) Under the condition of at least 20% lower than the blending addition theoretical value of two starting materials.
In order to solve one of the above technical problems, the technical scheme adopted by the invention is as follows: a thermoplastic cellulosic and aliphatic aromatic copolyester blend material having specific rheological properties, the blend material comprising from 20% to 80% by mass of a thermoplastic cellulosic and from 80% to 20% by mass of an aliphatic aromatic copolyester, characterized in that the melt viscosity of the blend is at least about 20% lower than the theoretical value of the blended addition of the two starting materials under low shear rate conditions; at least 20% lower than the blending addition theoretical value of the two starting materials under the condition of high shear rate; wherein the thermoplastic cellulose is selected from cellulose esters formed by cellulose and at least two organic acids, and the total number of carbon atoms of the organic acids is more than or equal to 6.
In the above technical solution, the term "low shear rate" means a shear rate of 100s-1(ii) a The high shear rate is 1000s-1Or 1363s-1。
In the above technical solution, the substitution degree of the thermoplastic cellulose is preferably greater than 1.0; more suitable cellulose derivatives have a degree of substitution of more than 1.5, particularly suitable cellulose derivatives have a degree of substitution of more than 2.0.
In the above-mentioned embodiment, the thermoplastic cellulose is preferably cellulose acetate butyrate ester, cellulose acetate valerate ester, cellulose acetate caproate ester, cellulose acetate enanthate ester, cellulose acetate caprylate ester, cellulose acetate pelargonate ester, cellulose acetate caprate ester, cellulose acetate laurate ester, cellulose acetate palmitate ester, cellulose acetate stearate ester, cellulose propionate butyrate ester, cellulose propionate valerate ester, cellulose propionate caproate ester, cellulose propionate enanthate ester, cellulose propionate caprylate ester, cellulose propionate pelargonate ester, cellulose propionate caprate ester, cellulose propionate laurate ester, cellulose propionate stearate ester, or the like.
In the above technical solution, the aliphatic aromatic copolyester is preferably a copolyester obtained by condensing alpha, omega-aliphatic diacid and aromatic diacid or derivatives thereof with aliphatic diol; the aliphatic diacid is preferably an alpha, omega-aliphatic diacid containing from 2 to 22 backbone carbon atoms, including: oxalic acid, 1, 3-malonic acid, succinic acid (1, 4-succinic acid), glutamic acid (1, 5-glutaric acid), adipic acid (1, 6-adipic acid), 1, 7-pimelic acid, 1, 8-suberic acid, 1, 9-azelaic acid, 1, 10-sebacic acid, and up to a carbon number of 22 dibasic acids; the derivatives of the aliphatic diacids include anhydrides, esters, acid halides, and the like prepared from the above diacids.
In the above technical solution, the aliphatic diacid is preferably an aliphatic diacid containing a substituent group; the substituent is preferably straight-chain alkyl, branched-chain alkyl, cyclic alkyl or alkyl with an unsaturated structure; and dibasic acids with other substituents such as cyclohexyl.
In the above embodiment, the aromatic diacid is preferably at least one diacid selected from terephthalic acid, 1, 4-naphthalenedicarboxylic acid, 2, 7-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, 2, 7-naphthalenedicarboxylic acid, 4, 4 '-diphenyletherdioic acid, 4, 3' -diphenyletherdioic acid, 4, 4 '-diphenylthioether-diacid, 4, 3' -diphenylthioether-diacid, 4, 4 '-diphenylsulfone-diacid, 4, 3' -diphenylsulfone-diacid, 4, 4 '-benzophenone-diacid, 4, 3' -benzophenone-diacid, and the like; the derivative of the aromatic diacid is preferably at least one selected from acid anhydrides, esters, acid halides and the like prepared from the above diacids.
In the above technical solution, the combination of the aliphatic diacid and the aromatic diacid includes at least one of the aliphatic diacid or the aliphatic diacid derivative and at least one of the aromatic diacid or the aromatic diacid derivative. Aliphatic diols suitable for preparing the aliphatic aromatic copolyester in the present invention include ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 1, 2-pentanediol, 1, 3-pentanediol, 1, 4-pentanediol, 1, 5-pentanediol, 1, 2-hexanediol, 1, 3-hexanediol, 1, 4-hexanediol, 1, 5-hexanediol, 1, 6-hexanediol, 1, 2-heptanediol, 1, 3-heptanediol, 1, 4-heptanediol, 1, 5-heptanediol, 1, 6-heptanediol, 1, 7-heptanediol, 1, 2-octanediol, 1, 3-octanediol, 1, 4-octanediol, 1, 5-octanediol, 1, 6-octanediol, 1, 7-octanediol, 1, 8-octanediol, 1, 2-nonanediol, 1, 3-nonanediol, 1, 4-nonanediol, 1, 5-nonanediol, 1, 6-nonanediol, 1, 7-nonanediol, 1, 8-nonanediol, 1, 9-nonanediol, 1, 2-decanediol, 1, 3-decanediol, 1, 4-decanediol, 1, 5-decanediol, 1, 6-decanediol, 1, 7-decanediol, 1, 8-decanediol, 1, 9-decanediol, 1, 10-decanediol up to a diol having a carbon number of 24 and diols having other substituents such as cyclohexyl.
In the above technical solution, the aliphatic aromatic copolyester is preferably poly (ethylene terephthalate-co-oxalate), poly (ethylene terephthalate-co-malonate), poly (ethylene terephthalate-co-succinate), poly (ethylene terephthalate-co-glutarate), poly (ethylene terephthalate-co-adipate), poly (ethylene terephthalate-co-suberate), poly (propylene terephthalate-co-oxalate), poly (propylene terephthalate-co-malonate), poly (propylene terephthalate-co-succinate), poly (propylene terephthalate-co-glutarate), poly (propylene terephthalate-co-adipate), poly (propylene terephthalate-co-suberate), poly (ethylene terephthalate-co-adipate), poly (ethylene terephthalate-co-suberate), poly (ethylene terephthalate-co-adipate), poly (ethylene terephthalate-co-, Polytrimethylene terephthalate-co-sebacate, polybutylene terephthalate-co-oxalate, polybutylene terephthalate-co-malonate, polybutylene terephthalate-co-succinate, polybutylene terephthalate-co-glutarate, polybutylene terephthalate-co-adipate, polybutylene terephthalate-co-suberate, polybutylene terephthalate-co-adipate, polyhexamethylene terephthalate-co-oxalate, polyhexamethylene terephthalate-co-malonate, at least one of poly (co-ethylene terephthalate-co-butylene succinate), poly (co-ethylene glutarate), poly (co-ethylene adipate), poly (co-ethylene suberate), etc.
In the technical scheme, the thermoplastic cellulose is preferably cellulose acetate butyrate, the thermoplastic cellulose and the aliphatic aromatic copolyester have a synergistic interaction effect, the blend of the thermoplastic cellulose and the aliphatic aromatic copolyester has the special rheological property, and the cellulose acetate butyrate is found to have better compatibility than other common thermoplastic cellulose (such as cellulose acetate, cellulose acetate propionate and the like) when being blended with the copolyester, namely, the problem of poor compatibility of the thermoplastic cellulose and the aliphatic aromatic copolyester is well solved, the compatibility of the thermoplastic cellulose and the aliphatic aromatic copolyester is good, the application range of the starting material can be greatly widened, and meanwhile, the special rheological property can reduce energy consumption in the material processing process.
In the above technical solution, the aliphatic aromatic copolyester is preferably polybutylene terephthalate-co-adipate (PBAT), polyethylene terephthalate-co-adipate (pea), polyethylene terephthalate-co-succinate (PEST), and polybutylene terephthalate-co-succinate (PBST).
In the above technical scheme, the blend material is most preferably a blend of 20 to 80 mass% of cellulose acetate butyrate and 80 to 20 mass% of polybutylene terephthalate-co-adipate or polybutylene terephthalate-co-succinate, the synergistic effect of the two is the best, and the rheological property and the compatibility of the obtained blend are both the best.
In the above technical solution, the number average molecular weight of the blend material is preferably at least greater than 20000g/mol, and more preferably at least greater than 40000 g/mol; the weight average molecular weight is preferably at least more than 60000g/mol, more preferably at least more than 80000 g/mol. .
In the above technical solution, the blend material preferably further contains at least one of a compatibilizer, an inorganic filler, an antioxidant, a lubricant, a colorant, and the like.
In the above solution, the melt viscosity of the blend is preferably at a low shear rate (100 s)-1) Under the condition that the ratio of the mass of the copolyester to the mass of the thermoplastic cellulose is at least 30% lower than the theoretical value of the additive ratio of the two starting materials (preferably 65% to 35% to 65%), and more preferably at least 35% lower (preferably 35% to 65%) of the additive ratio of the copolyester to the mass of the thermoplastic cellulose).
In the above-mentioned embodiments, the melt viscosity of the blend is preferably at a high shear rate (1000 or 1363 s)-1) Under the condition that the ratio of the mass of the copolyester to the mass of the thermoplastic cellulose is at least 25 percent lower than the theoretical value of the blending addition of the two starting materials (preferably, the mass ratio of the copolyester to the thermoplastic cellulose is 65 percent: 35 percent to 20 percent: 80 percent), and further preferably, at least 30 percent lower (preferably, the mass ratio of the copolyester to the thermoplastic cellulose is 35 percent: 65 percent to 20 percent: 80 percent).
In the above technical solution, the melt index of the blend material is preferably at least about 10% higher, more preferably at least about 40% higher (preferably 65% to 35% to 20% to 80% by mass of the copolyester to the thermoplastic cellulose), and more preferably at least about 60% higher (more preferably 35% to 65% by mass of the copolyester to the thermoplastic cellulose) than the theoretical value of the blend addition of the two starting materials.
The aliphatic aromatic copolyester applied to the invention can be prepared from various different aliphatic diacids, aromatic diacids and aliphatic diols through polymerization reaction. The catalyst for polymerization includes compounds containing metallic tin, antimony, titanium, etc. The titanium-based catalyst includes tetraisopropyl titanate, tetrabutyl titanate and the like. Aliphatic aromatic copolyesters include chain-extended aliphatic aromatic copolyesters, and various compounds or polymers having reactivity with carboxyl or hydroxyl groups can be used as chain extenders, including, for example, isocyanates having two or more functional groups such as Toluene Diisocyanate (TDI), hexamethylene diisocyanate (HMDI). Suitable chain extenders also include compounds containing multiple epoxy functional groups, such as those produced by BASF
ADR-4368C,
ADR-4368CS and the like. The chain extender of the present invention is present in an amount of from 0.2 to 4% by mass, and in some embodiments from 0.5 to 3% by mass.
The aliphatic aromatic copolyesters in the present invention include linear and branched copolyesters. The synthesis of branched copolyesters involves the addition of one or more branching agents during the synthesis. The branching agent is generally a polybasic acid having two or more carboxyl groups, a polyhydric alcohol or a polyhydroxy acid having two or more hydroxyl groups, or the like. Suitable branching agents include glycerol, trimethylolethane, trimethylolpropane, 1,2, 4-butanetriol, pentaerythritol, 1,2, 6-hexanetriol, sorbitol, 1,2, 3-benzenetricarboxylic acid (hemimellitic acid), 1,2, 4-benzenetricarboxylic acid (trimelitic acid), 1,3, 5-benzenetricarboxylic acid (trimesic acid), anhydrides, and the like.
In order to solve the second technical problem, the technical scheme adopted by the invention is as follows: the method for preparing the thermoplastic cellulose and aliphatic aromatic copolyester blend material with special rheological properties, which is disclosed by any one of the technical schemes, comprises the steps of adopting melt blending, and uniformly mixing the required amount of thermoplastic cellulose and the required amount of aliphatic aromatic copolyester in a molten state to obtain the thermoplastic cellulose and aliphatic aromatic copolyester blend material with special rheological properties.
In the above technical solution, the method is preferably a twin-screw continuous extrusion method.
In the technical scheme, the method preferably comprises the steps of continuously extruding and granulating the thermoplastic cellulose powder, blending the thermoplastic cellulose powder with the aliphatic aromatic copolyester according to a required ratio, and then adding the mixture into a double-screw extruder for extrusion and granulation.
In the above technical scheme, the method preferably comprises the steps of continuously extruding and granulating the thermoplastic cellulose powder, and then respectively metering the thermoplastic cellulose powder and the aliphatic aromatic copolyester into a double-screw extruder according to the required feeding proportion to perform extrusion granulation.
In the technical scheme, the method preferably comprises the step of respectively metering the thermoplastic cellulose powder and the aliphatic aromatic copolyester into a double-screw extruder according to a certain feeding proportion to perform extrusion granulation.
In the above technical solution, the screw rotation speed of the method is preferably 50rpm to 1500rpm.
In the above technical solution, the temperature of the method is preferably 140 ℃ to 240 ℃.
The materials and preparation methods used in the present invention are briefly described below:
1. thermoplastic cellulose
The thermoplastic cellulose is a cellulose derivative with a wide range, and the three hydroxyl groups on each repeated glucose unit of the cellulose derivative are partially or completely chemically modified in the forms of esterification or etherification and the like. The parameters characterizing the Degree of modification are the Degree of Substitution (Degree of Substitution), which is defined as the average number of substitutions in the three hydroxyl groups per repeating glucose unit, with a maximum of 3.0(3 hydroxyl groups are all substituted) and a minimum of 0 (pure cellulose).
The thermoplastic cellulose ester included in the present invention includes a mixed cellulose ester of cellulose and two or more kinds of organic aliphatic carboxylic acid, organic aliphatic acid anhydride and organic aliphatic acid halide, and the difference in the number of carbon atoms between different organic aliphatic carboxylic acid, organic aliphatic acid anhydride and organic aliphatic acid halide is 1 or more.
Cellulose esters are typically made by reacting natural cellulose with an organic acid, anhydride or acid chloride, etc., with a degree of substitution of the hydroxyl groups in the cellulose of from 0.5 to 2.8. Suitable cellulose ester products include Eastman, produced by Eastman chemical company, USATMCellulose acetate butyrate CAB-171-15, CAB-321-0.1, CAB-381-0.1, CAB-381-0.5, CAB-381-20, CAB-485-10, CAB-500-5, CAB-531-1 and the like. For example: CAB-531-1 contains 50% by mass of butyric acid component, 2.8% by mass of acetic acid component, and 1.7% by mass of hydroxyl component, and has a viscosity of 5.6 poise measured according to ASTM 1343. Cellulose esters are used in the fields of fibers, textiles, coatings, thermoplastic films, food additives, pharmaceutical industry and the like. In the coating industry, the addition of cellulose esters can improve the coating effect, including: hardness, flow, flatness, transparency, gloss, and the like. Cellulose Acetate Propionate (CAP) and Cellulose Acetate Butyrate (CAB) are two mixed cellulose esters that have a wide range of commercial uses.
2. Aliphatic aromatic copolyester
The aliphatic aromatic copolyester is a biodegradable plastic, and is prepared by condensation polymerization of one or more aliphatic diols, at least one aliphatic diacid or aliphatic diacid anhydride, aliphatic diacid halide and aliphatic diacid halide, at least one aromatic diacid or aromatic diacid anhydride, aromatic diacid halide and aromatic diacid halide.
3. Blends of thermoplastic cellulose and biodegradable aliphatic aromatic copolyesters
The blend disclosed by the invention consists of thermoplastic cellulose and biodegradable aliphatic aromatic copolyester, wherein the mass content of the thermoplastic cellulose is 20-80%, and the mass content of the biodegradable aliphatic aromatic copolyester is 80-20%. The blend comprises, in addition to the above composition, at least one additive selected from the group consisting of: compatibility agents, inorganic fillers, antioxidants, lubricants, colorants, and the like.
The physical and chemical properties (such as melt viscosity, melt index, etc.) of the polymer blend are mainly determined by the types and composition ratios of the polymers constituting the polymer blend. The polymer type mainly determines the compatibility between the components of the blend, which is a measure of the interaction between different polymers, and when the interaction between different polymers is strong, it can be stably and uniformly mixed on a molecular scale, it is called a miscible (mismixing) system; the interaction between other polymers is weak, and the polymers can be stably and uniformly dispersed in a nano scale although the polymers cannot be mutually dissolved in a molecular scale, so that the blend is called a compatible system; other polymers have weak interactions and even if they are mixed by force, they tend to form separate phase regions, and such blends are incompatible systems. Polymer blend glass transition temperature (' Tg") information can be used as a simple judgment basis for the compatibility among the components [ multicomponent polymer-principle, structure and performance, King's institute and editions, 2013, p.20-22 ], if the blend respectively keeps the glass transition temperature of the raw material components, the compatibility among the components is not good, and if the blend only has one glass transition temperature, the compatibility among the components is better. Under the condition of determined polymer types, a certain functional relationship exists between some physical and chemical properties (such as melt viscosity, melt index and the like) of the blend and the composition ratio thereof [ handbook of plastics engineering handbook, Huangrui kingdom, 2000, p.633-637; melt Rheology of Polymer Blends from Melt Flow Index, International Journal of Polymeric Materials,1984,10, p.213-235, one can generally infer and even design Blends with specific properties. In some cases with poor compatibilityIn mixed systems, it may happen that the viscosity of the blend is lower than that of the raw components [ fourth statistical mechanics, golden sun, 1998, p.630-633 ], the reason for this phenomenon being currently unknown, one of which is explained by the interfacial slip between the different phases leading to a decrease in the overall viscosity after mixing. Similar phenomena have not been reported in a blend system with good compatibility, and if the phenomena can be applied in a system with good compatibility, the phenomena have great potential.
The theoretical properties of some polymer blends can be generally presumed by using the addition rule, and the addition theory can be expressed by the following formula:
P＝c1P1+c2P2
p is a property of the blend, c1And P1Is the concentration and nature of component 1; c. C2And P2Is the concentration and nature of component 2. The properties (P) of the blend of the thermoplastic cellulose and the aliphatic aromatic copolyester can be calculated by an addition rule to obtain theoretically predicted values, namely, the theoretically predicted values are defined as 'addition theoretical values', and the values can be compared with experimentally detected values such as the apparent viscosity and the melt index. The concentration of the components can be expressed by mass fraction or volume fraction, and the mass fraction is selected to calculate a theoretical value in the invention.
A blend of cellulose acetate butyrate and a biodegradable polyester such as an aliphatic aromatic copolyester comprising polybutylene terephthalate-co-adipate (PBAT), polyethylene terephthalate-co-adipate (PEAT), polyethylene terephthalate-co-succinate (PEST), polybutylene terephthalate-co-succinate (PBST), etc. comprises 20 to 80% by mass of cellulose acetate butyrate and 80 to 20% by mass of an aliphatic aromatic copolyester, characterized in that the melt viscosity of the blend is at a low shear rate (e.g. 100 s)-1) Under conditions at least 20% lower than the theoretical value of the mixed addition of the two starting materials. Some of the more preferred compositions have melt viscosities at low shear rates (e.g., 100 s)-1) Under conditions of a mixed addition of the two starting materials to the theoretical valueThe content is 30 percent less; some of the most preferred compositions of the blends have melt viscosities at low shear rates (e.g., 100 s)-1) Under conditions at least 35% lower than the theoretical value of the mixed addition of the two starting materials.
A blend of cellulose acetate butyrate and a biodegradable polyester such as an aliphatic aromatic copolyester comprising polybutylene terephthalate-co-adipate (PBAT), polyethylene terephthalate-co-adipate (PEAT), polyethylene terephthalate-co-succinate (PEST), polybutylene terephthalate-co-succinate (PBST), etc., comprises 20 to 80% by mass of cellulose acetate butyrate and 80 to 20% by mass of an aliphatic aromatic copolyester, characterized in that the melt viscosity of the blend is at a high shear rate (e.g., 1000 or 1363 s)-1) Under conditions at least 20% lower than the theoretical value of the mixed addition of the two starting materials. Some more preferred compositions of blends have melt viscosities at high shear rates (e.g., 1000 or 1363 s)-1) Under conditions at least 25% lower than the theoretical value of the combined addition of the two starting materials; some of the most preferred compositions of the blends have melt viscosities at high shear rates (e.g., 1000 or 1363 s)-1) Under conditions at least 30% lower than the theoretical value of the mixed addition of the two starting materials.
The blend of cellulose acetate butyrate and biodegradable polyester such as aliphatic aromatic copolyester comprising polybutylene terephthalate-co-adipate (PBAT), polyethylene terephthalate-co-adipate (PEAT), polyethylene terephthalate-co-succinate (PEST), polybutylene terephthalate-co-succinate (PBST) and the like is characterized in that the melt index of the blend is at least about 10% higher than the theoretical value of the mixed addition of two starting materials, wherein the composition comprises 20 to 80% by mass of cellulose acetate butyrate and 80 to 20% by mass of aliphatic aromatic copolyester. Some more preferred compositions have a melt index at least 40% greater than the theoretical value of the mixed addition of the two starting materials; some of the most preferred compositions of the blend have a melt index at least 60% higher than the theoretical value of the combined addition of the two starting materials.
One method of preparing thermoplastic fiber of the inventionA method for blending vegetable and aliphatic aromatic copolyester. The method comprises uniformly mixing thermoplastic cellulose 20-80 wt% and aliphatic aromatic copolyester 80-20 wt% in a continuous process, and extruding and granulating to obtain a blend with low shear rate (100 s)-1) Under the condition, the additive ratio is at least 20 percent lower than the blending additive theoretical value of the two starting materials; at high shear rates (1000 or 1363 s)-1) Under the condition of at least 20% lower than the blending addition theoretical value of two starting materials.
The blends of the present invention, which are proportioned "unusually" and "unexpectedly" have lower apparent shear viscosities than the theoretical value of the additive mixing of pure thermoplastic cellulose and aliphatic aromatic copolyester starting materials, i.e., exhibit "concave" curves in the "apparent Viscosity-composition" relationship, which are manifested as "Melt Viscosity trap" (Melt Viscosity Well) phenomena, indicating that the blends have "Anti-Synergistic effects" of apparent Viscosity (Anti Effect or Anti-Synergistic Effect).
The blend of the present invention, which is composed in a certain proportion, has a Melt index (MFR: Melt Flow Rate) higher than the theoretical value of the mixed addition of pure thermoplastic cellulose and aliphatic aromatic copolyester starting material, i.e., in the relation of "Melt index-composition", it shows a "convex" curve, showing the phenomenon of "Melt index Peak" (MFR Peak), showing that the blend has a "Synergistic Effect" (Synergistic Effect) of Melt index.
The blends of the invention have a number average molecular weight of at least more than 20000g/mol and a weight average molecular weight of at least more than 60000 g/mol. The blends of the invention preferably have a number average molecular weight of at least greater than 40000g/mol and a weight average molecular weight of at least greater than 80000 g/mol.
4. Process for preparing blends of thermoplastic cellulose and biodegradable aliphatic aromatic copolyesters
The continuous melting preparation method comprises a two-step method and a one-step method. In the two-step method, thermoplastic cellulose powder is firstly granulated by a single-screw or double-screw extruder, then thermoplastic cellulose particles and aliphatic aromatic copolyester particles are uniformly mixed according to a certain proportion, and then the particle blend is added into a feeding port of the double-screw extruder by a feeding machine according to a certain feeding rate. The feeder can be a weight loss feeder or a volume feeder. The other embodiment is that two feeders are adopted to respectively meter the thermoplastic cellulose particles and the aliphatic aromatic copolyester particles into a double-screw extruder according to a certain feeding proportion for extrusion granulation.
The one-step method of the invention is that the thermoplastic cellulose powder is directly added into the feeding port of the double-screw extruder by one feeder according to a certain feeding rate without being processed and granulated by heat, meanwhile, the aliphatic aromatic copolyester particles are added into the feeding port of the double-screw extruder by the other feeder according to a certain feeding rate, the double-screw extrusion is carried out, and extruded sample strips are granulated by a water tank or underwater to prepare the blend particles. The extrudate can also be air cooled by an anhydrous process and then pelletized.
The extrusion temperature suitable for the present invention is 140 ℃ to a temperature at which the thermoplastic cellulose and the aliphatic aromatic copolyester are thermally decomposed. Generally suitable extrusion temperatures include 140 ℃ to 240 ℃. The rotational speed of the extruder includes 50rpm to 1500rpm, preferably 100rpm to 800 rpm.
Melt blending devices suitable for use in the present invention include a variety of mixers, Farrel continuous mixers, Banbury mixers, single screw extruders, twin screw extruders, multiple screw extruders (more than two screws), reciprocating single screw extruders such as Buss reciprocating single screw extruders (Buss Ko-Kneader), and the like. Preferred processes are continuous melt blending extrusion processes including twin screw extrusion processes. Continuous twin-screw extruders suitable for use in the present invention include twin-screw extruders of different designs, such as the ZSK Mcc18 co-rotating parallel twin-screw extruder manufactured by Coperion, Germany, and the like.
The thermoplastic cellulose prepared by the method of twin-screw continuous melt co-extrusion presented by the invention is blended with aliphatic aromatic copolyester, and has low melt viscosity which is 'unexpected'. One embodiment of the present invention is in phaseUnder the same conditions, the melt viscosity of the blend is lower than the mixing addition theoretical value of the thermoplastic cellulose and the aliphatic aromatic copolyester starting materials. This viscosity reduction is prevalent, including at lower shear rates such as 100s-1And at higher shear rates, e.g. 1000 or 1363s-1. At 100s-1The melt viscosity of the blend is at least 20% lower than the theoretical value of the mixed addition of the two starting materials at shear rate. Some more preferred compositions (mass ratio of copolyester to thermoplastic cellulose 65%: 35% to 35%: 65%) of the blend have a melt viscosity at least 30% lower than the theoretical value of the mixed addition of the two starting materials, and some most preferred compositions (mass ratio of copolyester to thermoplastic cellulose 35%: 65%) of the blend have a melt viscosity at least 35% lower than the theoretical value of the mixed addition of the two starting materials. At 1000 or 1363s-1The melt viscosity of the blend at shear rate is at least 20% lower than the theoretical value of the mixed addition of the two starting materials, some more preferred compositions (65% by mass copolyester to thermoplastic cellulose: 35% to 20% to 80%) of the blend have a melt viscosity at least 25% lower than the theoretical value of the mixed addition of the two starting materials, and some most preferred compositions (35% by mass copolyester to thermoplastic cellulose: 65% to 20% to 80%) of the blend have a melt viscosity at least 30% lower than the theoretical value of the mixed addition of the two starting materials.
One concrete embodiment of the thermoplastic cellulose and aliphatic aromatic copolyester blend material prepared by the invention is that the melt index of the blend is higher than the mixing addition theoretical value of two starting materials. The melt index of the blend of preferred composition is at least about 10% higher than the theoretical value of the combined addition of the two starting materials, more preferably the melt index of the blend of composition (65% by mass copolyester to thermoplastic cellulose: 35% to 20% to 80%) is at least 40% higher than the theoretical value of the combined addition of the two starting materials, and most preferably the melt index of the blend of composition (35% by mass copolyester to thermoplastic cellulose: 65%) may be at least 60% higher than the theoretical value of the combined addition of the two starting materials.
The thermoplastic cellulose and aliphatic aromatic copolyester blend material prepared by the continuous extrusion blending method disclosed by the invention has lower melt viscosity and higher melt index than the theoretical value of the mixing addition of two pure raw materials, has wide application potential, can be used in the fields of traditional fibers, films, injection molding and the like, can also be used in the fields of 3D printing wires and the like, and achieves better technical effects.
Drawings
FIG. 1180 ℃ is a plot of apparent shear viscosity versus shear rate for each PBAT/CAB particle.
FIG. 2180 ℃ for each PBAT/CAB particle at 100s-1The dashed line in the figure is a line of addition theory calculated values for the relationship between apparent shear viscosity and composition at shear rate of (2).
FIG. 3180 ℃ for each PBAT/CAB particle at 1363s-1The dashed line in the figure is a line of addition theory calculated values for the relationship between apparent shear viscosity and composition at shear rate of (2).
FIG. 4 DSC cooling curves for each PBAT/CAB particle.
FIG. 5 DSC second temperature rise profile for each PBAT/CAB particle.
FIG. 6 relationship of glass transition temperature and composition for each PBAT/CAB particle.
Fig. 7 TGA curves of each PBAT/CAB particle under air atmosphere.
FIG. 8 is a graph showing the relationship between the melt index (190 ℃,2.16kg) and the composition of each PBAT/CAB particle, in which the dotted line is a line of addition theory calculation values.
FIG. 9180 ℃ is a graph of apparent shear viscosity versus shear rate for each PBST/CAB particle.
FIG. 10180 ℃ for each PBST/CAB particle at 100s-1The dashed line in the figure is a line of addition theory calculated values for the relationship between apparent shear viscosity and composition at shear rate of (2).
FIG. 11180 ℃ for each PBST/CAB particle at 1000s-1The dashed line in the figure is a line of addition theory calculated values for the relationship between apparent shear viscosity and composition at shear rate of (2).
FIG. 12 is a graph showing the relationship between the melt index (190 ℃,2.16kg) and the composition of each PBST/CAB particle, wherein the dotted line represents a line of addition theoretical calculation values.
FIG. 13180 ℃ graph shows the apparent shear viscosity versus shear rate for each PBAT/CAP particle.
FIG. 14180 ℃ for each PBAT/CAP particle at 100s-1The dashed line in the figure is a line of addition theory calculated values for the relationship between apparent shear viscosity and composition at shear rate of (2).
FIG. 15180 ℃ for each PBAT/CAP particle at 1000s-1The dashed line in the figure is a line of addition theory calculated values for the relationship between apparent shear viscosity and composition at shear rate of (2).
FIG. 16 is a graph showing the relationship between the melt index (190 ℃ C., 2.16kg) and the composition of each PBAT/CAP particle, wherein the dotted line is a line representing the calculated value of the addition theory.
FIG. 17 DSC cooling curves for each PBAT/CAP particle.
FIG. 18 DSC second temperature rise profile for each PBAT/CAP particle.
The invention carries out performance measurement according to the following method:
melt index (MFR) determination method: according to ISO 1133 standard, Lloyd DAVENPORT is adoptedTMThe melt index was measured by an MFI-10/230 melt index meter, the cylinder temperature was 190 ℃, the weight load was 2.16kg, the diameter of the die was 2.095mm, the length was 8mm, the preheating time was 4min, samples were automatically cut at set intervals, 5 times of averaging was performed, and the measurement result was expressed in grams per 10 minutes (g/10 min).
Rheological behavior determination method: measured by a Malvern Instruments Rosand RH7 hot high pressure capillary rheometer with the processing software of Lannch
Version 8.60. The test uses a sensor with 10000Psi pressure and a 16/1.0/180 round hole type capillary die. For batch loading compaction at the time of loading, two 0.5MPa preloads and 2 minute preheats were performed prior to testing to ensure complete melting and compaction of the particles at the selected temperature (180 ℃).
Thermogravimetric analysis (TGA): the testing was performed on a Discovery series thermogravimetric analyzer from TA Instruments with the processing software TA Instruments Trios version 3.1.4. The temperature of the isobalance chamber was required to be stabilized at 40 ℃ before testing. During testing, 5-10 mg of sample is weighed and placed in a ceramic crucible, and the test is carried out in the air atmosphere with the flow rate of 20mL/min, the temperature rise range is 30-600 ℃, and the temperature rise rate is 10 ℃/min.
Thermal performance analysis (DSC): the tests were performed on a Discovery series Differential Scanning Calorimeter (DSC) manufactured by TA Instruments, Inc., with the processing software TA Instruments Trios version 3.1.5, equipped with a calibrated Cooling System 90 mechanical refrigeration accessory. The testing atmosphere is 50mL/min of nitrogen, and the amount of the sample required by the test is 5-10 mg. The test procedure was as follows: the temperature is stabilized at 40 ℃, then the temperature is raised to 250 ℃ at the speed of 10 ℃/min and the temperature is kept constant for 2min to remove the thermal history, then the temperature is lowered to-70 ℃ at the speed of 10 ℃/min, and then the temperature is raised to 250 ℃ at the speed of 10 ℃. And recording the temperature reduction process and the second temperature rise process to research the thermal performance of the sample. By DSC measurement, software can be used to directly derive the crystallization temperature ("T") of a samplec"), melting temperature (" T ")m"), glass transition (" T ")g"), enthalpy change (". DELTA.H "), etc.
Detailed Description
The present invention is specifically described by the following examples. It should be noted that the following examples are given solely for the purpose of illustration and are not to be construed as limitations on the scope of the invention, as many insubstantial modifications and variations of the invention may be made by those skilled in the art in light of the above teachings.
Comparative example 1
The polybutylene terephthalate-co-adipate (PBAT) used in the present invention is manufactured by BASF corporation, Germany, and is available under the brand name
F BX 7011. Raw materials
F BX 7011 PBAT particles from PolyLab HAAKE, Thermo Fisher science, USATMRheomex OS PTW16 was pelletized by extrusion from a co-rotating twin-screw extruder (screw diameter 16mm, L/D. 40) as a comparative example. TheThe extruder has a total of 11 sections from the feed port to the die, numbered 1-11, wherein section 1 serves only as a feed and is not heated. A volume type particle feeder attached to the extruder and used for feeding the particles after calibration
Feeding the F BX 7011 PBAT raw material into a double screw at a feeding speed of 2100 g/hr. The temperatures of 2-11 sections of the extruder are respectively as follows: 140 ℃,150 ℃,160 ℃,160 ℃,160 ℃,160 ℃ and 160 ℃, the screw rotation speed is set at 200rpm, and the torque is 50-60%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 18.98g/10 min.
Comparative example 2
Cellulose Acetate Butyrate (CAB) used in this comparative example was manufactured by Eastman corporation of America under the trademark EastmanTMCAB-531-1. Raw material EastmanTMCAB-531-1 powder prepared from PolyLab HAAKE of Thermo Fisher scientific Co., USATMRheomex OS PTW16 was pelletized by extrusion from a co-rotating twin-screw extruder (screw diameter 16mm, L/D. 40) as a comparative example. The extruder has a total of 11 sections from the feed port to the die, numbered 1-11, wherein section 1 serves only as a feed and is not heated. The attached volumetric powder feeder of the extruder is used for Eastman after being calibratedTMFeeding CAB-531-1 raw material into twin screws at a feeding speed of 1000 g/hr. The temperatures of 2-11 sections of the extruder are respectively as follows: 140 ℃,150 ℃,160 ℃,160 ℃,160 ℃,160 ℃ and 160 ℃, the screw rotation speed is set at 200rpm, and the torque is 60-70%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 8.96g/10 min.
[ example 1 ]
[ example 2 ]
[ example 3 ]
[ example 4 ]
[ example 5 ]
[ example 6 ]
All 7 of the above particles, including comparative examples 1-2 and examples 1-5, were subjected to rheological behavior measurements on a Malvern Instruments Rosand RH7 hot high pressure capillary rheometer according to the test methodAs described above, the test was chosen to determine the apparent shear viscosity at the following shear rates: 100,192,369,709,1363,2615 and 5019s-1. . The apparent shear viscosity of each particle at 180 ℃ is related to the shear rate in FIG. 1. Wherein the shear rate is 100s-1And 1363s-1The apparent shear viscosity versus composition is shown in FIGS. 2 and 3, respectively, with specific values listed in tables 1 and 2.
From FIG. 1, it can be seen that the shear thinning phenomenon, i.e., the shear viscosity decreases with increasing shear rate, is very common in polymer systems, indicating that the basic properties of the system do not change significantly after blending. And in most cases, especially at high shear rates, the apparent shear viscosity of the mixture is mostly below that of the two pure materials under the same conditions, i.e. the viscosity of the two materials decreases after mixing. Referring specifically to fig. 2 and 3, it has been found that the apparent shear viscosity of the blended particles is almost always less than that of either pure starting material, and the viscosity curve is "concave," an unexpected phenomenon of "viscosity trapping," which indicates that the blended particles become less viscous at both high and low shear rates, a property that is rarely encountered in compatible polymer blends.
Some performance parameters after blending of the polymer can be presumed by addition theoretical values, and are determined according to the following formula:
P＝c1P1+c2P2
wherein P is the theoretical value of addition, P1The corresponding parameter values for component 1 in the mixture, c1Is its mass fraction, P2The corresponding parameter value of component 2 in the mixture, c2Is the mass fraction thereof. If the measured value of the mixture parameter differs more from the theoretical value of the addition, a more pronounced synergistic (or anti-synergistic) action between the components is indicated.
From Table 1, it can be found that when the shear rate is 100s-1When compared, the apparent shear viscosity of the actual blend is about 20.3% (example 1) to 34.4% (example 4) lower than the theoretical value of addition.
From Table 2, it can be found that when the shear rate is 1363s-1When the apparent shear viscosity ratio of the actual blend is additiveThe theoretical value is about 20.7% (example 1) to 31.9% (example 4) lower.
[ example 7 ]
All of the above 7 particles, including comparative examples 1-2 and examples 1-5, were subjected to Differential Scanning Calorimetry (DSC) tests according to the procedure described above, and the cooling curves and the second heating curves are shown in fig. 4 and 5, respectively. The crystallization temperature ("T") can be directly derived therefrom by softwarec"), melting temperature (" T ")m"), glass transition (" T ")g"), enthalpy change (". DELTA.H "), and the like, and specific values are shown in Table 3. Glass transition temperature ("T") of each particleg") versus composition is shown in fig. 6.
From fig. 4 and 5 it can be seen that the crystallinity gradually decreases as the PBAT content in the blend decreases, as indicated by a gradual decrease in crystallization temperature and a smaller crystallization peak, and no distinct crystallization and melting peaks are observed when the mass fraction of PBAT decreases to 50% and below (see table for details, 3). All particles have only one glass transition temperature ("Tg") indicates that the compatibility of the components in the blended particles is good, and TgThe values of (a) increase with increasing CAB content, see fig. 6.
[ example 8 ]
All 7 of the above particles, including comparative examples 1-2 and examples 1-5, were subjected to thermogravimetric analysis (TGA) testing according to the procedure described above, and the results of the testing are shown in fig. 7. It can be seen from the figure that the thermal decomposition curves of the particles after blending are substantially between the curves of the two comparative examples, indicating that the thermal decomposability of CAB and PBAT did not change much before and after blending, which is in line with the expectation.
[ example 9 ]
All of the above 7 types of particles, including comparative examples 1-2 and examples 1-5, were subjected to melt index (MFR) testing (190 ℃,2.16kg) according to the procedure described above, and the relationship between the measured MFR values and the composition is shown in FIG. 8. The specific values obtained from FIG. 8 are listed in Table 4, which includes the "theoretical values for addition" mentioned above.
From Table 4, it can be seen that the actual melt index of example 1 is 1.54g/10min higher than the theoretical value of addition after melt blending PBAT and CAB, the percentage being about 9.1%; the actual melt index of example 4 was 7.36g/10min higher than the theoretical value of addition, the percentage was about 59.1%, and the percentage value in the examples was the largest. All of these exceptionally high melt indices are unexpected, rare in well-compatible polymer blend systems, and not yet discovered in CAB and PBAT blends.
Comparative example 3
The poly (butylene terephthalate) -co-succinate (PBST) used in the invention is self-made, the preparation process refers to the research on nucleating agent and copolymerization modification of poly (butylene terephthalate) -co-succinate (PBST), 2013, Master thesis, succinic acid and terephthalic acid respectively account for 50% of the molar ratio of the total diacid feeding amount, butanediol is slightly overdosed, and the prepared PBST intrinsic viscosity is about 1.20, wherein no nucleating agent or other auxiliary agents are added. Self-made PBST particles, using PolyLab HAAKE from Thermo Fisher technologies, USATMRheomex OS PTW16 was pelletized by extrusion from a co-rotating twin-screw extruder (screw diameter 16mm, L/D. 40) as a comparative example. The extruder has a total of 11 sections from the feed port to the die, numbered 1-11, wherein section 1 serves only as a feed and is not heated. The extruder was accompanied by a volumetric particle feeder, calibrated to feed the homemade PBST particles to the twin screw, at a feed rate of 1800 g/hr. The temperatures of 2-11 sections of the extruder are respectively as follows: 160 ℃,170 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃, and 180 ℃, the screw speed is set at 200rpm, and the torque is 55-61.5%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 5.73g/10 min.
Comparative example 4
Cellulose Acetate Butyrate (CAB) used in this comparative example was manufactured by Eastman corporation of America under the trademark EastmanTMCAB-381-0.5. Raw material EastmanTMCAB-381-0.5 powder, PolyLab HAAKE from Thermo Fisher scientific, USATM Rheomex OS PTW16 was pelletized by extrusion from a co-rotating twin-screw extruder (screw diameter 16mm, L/D40) as a comparative example. The extruder has a total of 11 sections from the feed port to the die, numbered 1-11, wherein section 1 serves only as a feed and is not heated. The attached volumetric powder feeder of the extruder is used for Eastman after being calibratedTMCAB-381-0.5 raw material is fed into the twin screw, and the feeding speed is 900 g/hr. The temperatures of 2-11 sections of the extruder are respectively as follows: 160 ℃,170 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃, and 180 ℃, the screw speed is set at 200rpm, and the torque is 68-70%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 6.01g/10 min.
[ example 10 ]
Self-made PBST particles and EastmanTMCAB-381-0.5 PolyLab HAAKE as mentioned hereinaboveTMMelt blending and extruding in a Rheomex OS PTW16 co-rotating twin-screw extruder for granulation. In section 1 of the extruder, a calibrated volumetric particle feeder was used to feed the homemade PBST particles at the rate: 1440g/hr, while a calibrated volumetric powder feeder was used for EastmanTMFeeding CAB-381-0.5 powder at the speed of: 360 g/hr. The temperatures of 2-11 sections of the extruder are respectively as follows: 160 ℃,170 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃, and 180 ℃, the screw speed is set at 200rpm, and the torque is 53-57%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 8.15g/10 min.
[ example 11 ]
Self-made PBST particles and EastmanTMCAB-381-0.5 PolyLab HAAKE as mentioned hereinaboveTMMelt blending and extruding in a Rheomex OS PTW16 co-rotating twin-screw extruder for granulation. In section 1 of the extruder, a calibrated volumetric particle feeder was usedThe self-made PBST particle feed is carried out at the speed of: 1170g/hr, while a calibrated volumetric powder feeder was used for EastmanTMFeeding CAB-381-0.5 powder at the speed of: 630 g/hr. The temperatures of 2-11 sections of the extruder are respectively as follows: 160 ℃,170 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃, and 180 ℃, the screw speed is set at 200rpm, and the torque is 52-54%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 11.89g/10 min.
[ example 12 ]
Self-made PBST particles and EastmanTMCAB-381-0.5 PolyLab HAAKE as mentioned hereinaboveTMMelt blending and extruding in a Rheomex OS PTW16 co-rotating twin-screw extruder for granulation. In section 1 of the extruder, a calibrated volumetric particle feeder was used to feed the homemade PBST particles at the rate: 900g/hr, while the calibrated volumetric powder feeder is used in EastmanTMFeeding CAB-381-0.5 powder at the speed of: 900 g/hr. The temperatures of 2-11 sections of the extruder are respectively as follows: 160 ℃,170 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃, and 180 ℃, the screw speed is set at 200rpm, and the torque is 54.5-60%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 13.02g/10 min.
[ example 13 ]
Self-made PBST particles and EastmanTMCAB-381-0.5 PolyLab HAAKE as mentioned hereinaboveTMMelt blending and extruding in a Rheomex OS PTW16 co-rotating twin-screw extruder for granulation. In section 1 of the extruder, a calibrated volumetric particle feeder was used to feed the homemade PBST particles at the rate: 630g/hr, while a calibrated volumetric powder feeder was used for EastmanTMFeeding CAB-381-0.5 powder at the speed of: 1170 g/hr. Extruding machineThe temperatures of the sections 2 to 11 are respectively as follows: 160 ℃,170 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃, and 180 ℃, the screw speed is set at 200rpm, and the torque is 62-68%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 13.69g/10 min.
[ example 14 ]
Self-made PBST particles and EastmanTMCAB-381-0.5 PolyLab HAAKE as mentioned hereinaboveTMMelt blending and extruding in a Rheomex OS PTW16 co-rotating twin-screw extruder for granulation. In section 1 of the extruder, a calibrated volumetric particle feeder was used to feed the homemade PBST particles at the rate: 300g/hr, while a calibrated volumetric powder feeder was used for EastmanTMFeeding CAB-381-0.5 powder at the speed of: 1200 g/hr. The temperatures of 2-11 sections of the extruder are respectively as follows: 160 ℃,170 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃, and 180 ℃, the screw speed is set at 200rpm, and the torque is 61.5-70%. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. Collecting particles, vacuum drying at 60 deg.C for 4hr, and packaging. The melt index of the particles at 190 ℃ under 2.16kg was 13.45g/10 min.
[ example 15 ]
The rheological behaviour of the above 7 particles, including comparative examples 3 to 4 and examples 10 to 14, was determined on a Malvern Instruments Rosand RH7 hot high pressure capillary rheometer, the test method being as hereinbefore described, with the following shear rates selected for the determination of the apparent shear viscosity: 30,100,200,500,1000,2000 and 5000s-1. The apparent shear viscosity of each particle at 180 ℃ is plotted against shear rate in FIG. 9. Wherein the shear rate is 100s-1And 1000s-1The apparent shear viscosity versus composition is shown in FIGS. 10 and 11, respectively, with specific values listed in tables 5 and 6.
From FIG. 9, it can be seen that the shear thinning phenomenon, i.e., the shear viscosity decreases with increasing shear rate, is very common in polymer systems, indicating that the basic properties of the system do not change significantly after blending. And in most cases, especially at high shear rates, the apparent shear viscosity of the mixture is mostly below that of the two pure materials under the same conditions, i.e. the viscosity of the two materials decreases after mixing. Referring specifically to fig. 10 and 11, it can be seen that the apparent shear viscosity of the blended particles is almost lower than that of either pure starting material, and the viscosity curve is "concave," i.e., an unexpected "viscosity trap," which indicates that the blended particles become less viscous at both high and low shear rates, a property that is rarely encountered in compatible polymer blends.
Some performance parameters after blending of the polymer can be presumed by addition theoretical values, and are determined according to the following formula:
P＝c1P1+c2P2
wherein P is the theoretical value of addition, P1The corresponding parameter values for component 1 in the mixture, c1Is its mass fraction, P2The corresponding parameter value of component 2 in the mixture, c2Is the mass fraction thereof. If the measured value of the mixture parameter differs more from the theoretical value of the addition, a more pronounced synergistic (or anti-synergistic) action between the components is indicated.
From Table 5, it can be found that when the shear rate is 100s-1When compared, the apparent shear viscosity of the actual blend is about 19.1% (example 10) to 62.9% (example 13) lower than the theoretical value of addition.
From Table 6, it can be found that when the shear rate is 1000s-1When the actual blend apparent shear viscosity is about 35.0% (example 10) to 65.0% (example 14) lower than the addition theoretical value.
[ example 16 ]
The above 7 types of particles, including comparative examples 3-4 and examples 10-14, were subjected to melt index (MFR) tests (190 ℃,2.16kg) according to the procedure described above, and the relationship between the measured MFR values and the composition is shown in FIG. 15. The specific values obtained from FIG. 12 are shown in Table 7, which includes the "theoretical values for addition" mentioned above.
From Table 7, it can be seen that the actual melt index of example 10 is 2.36g/10min higher than the theoretical value of addition after melt blending PBST and CAB, the percentage being about 40.9%; the actual melt index of example 13 was 7.78g/10min higher than the theoretical value of addition, the percentage was about 131.6%, and the percentage value in the examples was the largest. All of these exceptionally high melt indices are unexpected, rare in compatible polymer blend systems, and not yet discovered in PBST and CAB blends.
Comparative example 5
To verify that the specific low shear viscosity and high melt index phenomena of examples 1-5 and examples 10-14 are not common when biodegradable aliphatic aromatic copolyesters are blended with thermoplastic cellulose esters,
f BX 7011 PBAT with another thermoplastic cellulose CAP (Eastman)TMCAP 375E4000012) was melt blended extruded using a similar process. The mixing ratio is selected as PBAT/CAP (mass ratio): 0/100,20/80,50/50,80/20 and 100/0. Mixing was also carried out in PolyLab HAAKETMRheomex OS PTW16 co-rotating twin-screw extruder, and proportionally and simultaneously adding into the 1 st section of the extruder by using a volumetric feeder of the extruder
F BX 7011 PBAT and EastmanTMCAP 375E 4000012. The temperatures of 2-11 sections of the extruder are respectively as follows: 160 ℃,170 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃,180 ℃ and 180 ℃, the screw speed being set at 200 rpm. The extruder is provided with a circular neck ring die with the diameter of 3mm, and a sample strip is extruded from the neck ring die, cooled in water bath and cut into cylindrical particles with the diameter of about 3mm by a granulator. The particles were collected, evacuated in a vacuum oven at 60 ℃ for 4 hours, and then packaged for use.
The above five kinds of dried PBAT/CAP particles are tested for capillary rheological property at 180 deg.C according to the method described above, and apparent shear viscosity at the following shear rate is selected during the testDegree: 30,100,200,500,1000,2000 and 5000s-1. The results of the tests are shown in fig. 13, from which it can be seen that the viscosity curve for the majority of the mixed particles is between the two pure raw materials. Low shear rate (100 s)-1) And high shear rate (1000 s)-1) The apparent viscosity versus composition of the resulting polymer is shown in FIGS. 14 and 15, respectively, from which it can be seen that the polymer is produced at low shear rates (100 s) in both FIGS. 14 and 15-1) Or high shear rate (1000 s)-1) The shear viscosity of the mixed particles was around the addition theoretical value, and the phenomenon of "melt viscosity trap" as shown in fig. 2,3, 10 and 11 was not observed. This indicates that the "melt viscosity trap" phenomenon in fig. 2,3, 10 and 11 is indeed an "unexpected" technical effect.
The Melt Flow Rate (MFR) of the above five dried PBAT/CAP particles was determined as described above, and the results are shown in FIG. 16. It can be seen from the figure that in the PBAT/CAP system, there is no "melt index peak" phenomenon as presented in fig. 8 and fig. 12, but rather a certain degree of melt index drop occurs after mixing PBAT and CAP. This indicates the "melt index peak" phenomenon in fig. 8 and 12, and indeed the "unexpected" technical effect.
The above five PBAT/CAP particles were subjected to DSC test according to the method described above, and the cooling curve and the second heating curve are shown in fig. 17 and fig. 18, respectively. It is evident from FIGS. 17 and 18 that the PBAT and CAP raw materials after mixing still maintain their respective crystallization temperatures of about 82 deg.C and 77 deg.C, respectively, and their respective melting temperatures of about 134 deg.C and 92 deg.C, respectively, although no significant glass transition temperature (T) is seen for CAPg) T before and after mixing of PBATgThe data above, which are always maintained at about-29 c, show poor compatibility of PBAT and CAP in the blend, phase separation of the two, and crystallization in separate phase regions. From FIGS. 4 to 6, it can be seen that only one T is present after blending PBAT and CABgAnd the crystallization process is also changed remarkably, namely the compatibility of PBAT and CAB is good.
Through the above differences, the inventors unexpectedly found that the blend properties of different celluloses and the poly aliphatic aromatic copolyester of the present invention are very different, for example, CAP and CAB are thermoplastic celluloses commonly used in the art, but the blend composite materials of CAP and CAB and aliphatic aromatic copolyester have very different properties, and the surprisingly found blend of thermoplastic cellulose and aliphatic aromatic copolyester, especially but not limited to the blend of PBAT and CAB and the blend of PBST and CAB, has good synergistic effect, not only good rheological properties, but also good compatibility, and can greatly widen the application range of the starting materials, and simultaneously can reduce the energy consumption in the material processing process.
TABLE 1180 ℃ shear rate of 100s-1The measured apparent shear viscosity, the theoretical shear viscosity, and the difference and the percentage difference between the two
TABLE 2180 ℃ measured apparent shear viscosity at a shear rate of 1363s-1, theoretical apparent shear viscosity, and difference and percent difference between the two
Table 3 thermal performance parameters of each particle obtained from DSC results.
Table 4 measured melt index (190 ℃,2.16kg) and addition theoretical melt index and the difference and percent difference between the two
TABLE 5180 ℃ measured apparent shear viscosity at shear rate of 100s-1, theoretical apparent shear viscosity, and difference and percent difference between the two
TABLE 6180 ℃ measured apparent shear viscosity at shear rate 1000s-1, theoretical apparent shear viscosity and difference and percent difference between
Table 7 measured melt index (190 ℃,2.16kg) and addition theoretical melt index and the difference and percent difference between the two
Claims (5)
1. A thermoplastic cellulose and aliphatic aromatic copolyester blend material with special rheological property, which comprises 35 to 65 mass percent of thermoplastic cellulose and 65 to 35 mass percent of aliphatic aromatic copolyester, and is characterized in that the melt viscosity of the blend is at least 30 percent lower than the blending addition theoretical value of two starting materials under the condition of low shear rate; at least 30% lower than the blending addition theoretical value of the two starting materials under the condition of high shear rate; wherein the thermoplastic cellulose is cellulose acetate butyrate; the aliphatic aromatic copolyester is at least one of polybutylene terephthalate-co-adipate and polybutylene terephthalate-co-succinate.
2. The thermoplastic cellulose and aliphatic aromatic copolyester blend material with special rheological properties according to claim 1, wherein the degree of substitution of the thermoplastic cellulose is more than 1.0.
3. Thermoplastic cellulosic and aliphatic-aromatic copolyester blend material with special rheological properties according to claim 1 characterized in that the number-average molecular weight of the blend is at least more than 20000g/mol and the weight-average molecular weight is at least more than 60000 g/mol.
4. The thermoplastic cellulosic and aliphatic aromatic copolyester blend material with special rheological properties according to claim 1 characterized in that the melt index of the blend is at least 10% higher than the blending theoretical addition value of the two starting materials.
5. A method for preparing the thermoplastic cellulose and aliphatic aromatic copolyester blend material with special rheological properties as claimed in any one of claims 1 to 4, wherein continuous melt blending extrusion is adopted, a required amount of thermoplastic cellulose and a required amount of aliphatic aromatic copolyester are uniformly mixed in a molten state, and extrusion granulation is carried out to obtain the thermoplastic cellulose and aliphatic aromatic copolyester blend material with special rheological properties.
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