CN114075343A - Novel hydrophobically modified starch film and preparation method thereof - Google Patents
Novel hydrophobically modified starch film and preparation method thereof Download PDFInfo
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- CN114075343A CN114075343A CN202110957156.9A CN202110957156A CN114075343A CN 114075343 A CN114075343 A CN 114075343A CN 202110957156 A CN202110957156 A CN 202110957156A CN 114075343 A CN114075343 A CN 114075343A
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- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
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- C08J5/18—Manufacture of films or sheets
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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- C08J2303/00—Characterised by the use of starch, amylose or amylopectin or of their derivatives or degradation products
- C08J2303/02—Starch; Degradation products thereof, e.g. dextrin
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- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
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Abstract
The invention provides a novel hydrophobically modified starch film which is prepared by a layered multiple casting process, adopts a three-layer structure which is hydrophobically modified by alkyl ketene dimer and has the characteristics of homogeneity and heterogeneous self-reinforcement, the outer layer is hydrophobic, the inner layer provides excellent mechanical property, the excellent property of the starch film is maintained to the maximum extent, the hydrophilicity of the starch film is reduced, and the hydrophobic property of the starch film is improved.
Description
Technical Field
The invention relates to a waterproof starch film, in particular to a waterproof starch film taking alkyl ketene dimer as a modifier and a preparation method thereof.
Background
Starch is widely considered as a biodegradable material with development potential due to the advantages of abundant reserves, low price, good plasticity, safe use and the like. However, in practical application, the starch product can easily absorb moisture in the environment due to the large amount of hydroxyl groups naturally existing in the starch and the large amount of plasticizer (such as glycerol, polyethylene glycol and the like) added in the material preparation process, so that the related product collapses and deforms, the mechanical property is poor, and the use value of the starch product is seriously affected. Therefore, how to reduce the hydrophilicity of the material and widen the application scene of the product becomes a key problem to be solved urgently in the application of the starch material.
Alkyl Ketene Dimer (AKD) is waxy solid, contains a lactone ring with high chemical activity in the molecular structure, can be subjected to esterification reaction with hydroxyl in a starch material to generate beta-ketoester, and achieves the hydrophobic purpose by converting the hydroxyl which is easy to be hydrophilic into ester group. However, direct blending with the starch matrix leads to microphase separation behavior, which in turn leads to a reduction in mechanical properties. Therefore, the hydrophobic modified starch film with the self-reinforced structure is prepared by a layered multiple casting process, and good hydrophobicity and mechanical properties can be obtained simultaneously.
Disclosure of Invention
The invention aims to solve the problem that the mechanical property of a film material is reduced due to the phase separation action generated by directly blending a hydrophobic substance and starch, and provides a novel hydrophobically modified starch film and a preparation method thereof. The film is prepared by layering and multiple tape casting, can maintain the excellent performance of the starch film to the maximum extent, reduce the hydrophilicity of the starch film and improve the hydrophobic performance of the starch film.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the first purpose of the invention is to provide a novel hydrophobically modified starch film, and the added modifier is alkyl ketene dimer.
In one or more embodiments, the hydrophobically modified starch film comprises dry starch, water, plasticizers, and the like in a common starch film; or alkyl ketene dimer is added in the preparation method of the common starch film to achieve the aim of hydrophobicity.
The second purpose of the invention is to provide a preparation method of the hydrophobic modified starch film, which comprises the following steps:
(1) mixing starch with water to prepare a suspension with the concentration of 3-8 wt%; adding a plasticizer which is 20-40% of the weight of the dry starch, and continuously stirring in a constant-temperature water bath kettle at 90-95 ℃ until the starch is fully gelatinized; reducing the temperature of the water bath to 40-70 ℃ while keeping stirring, adding alkyl ketene dimer, and fully homogenizing the solution after the alkyl ketene dimer is completely melted to obtain a starch film forming solution I;
(2) casting the starch film-forming solution I prepared in the step (1) on a flat plate, and then placing the flat plate in a constant temperature and humidity cabinet for drying for 2-5 hours to obtain a film I tightly attached to the surface of the flat plate;
(3) repeating the step (1) again without adding alkyl ketene dimer to obtain a starch film-forming solution II; pouring the film forming solution on the surface of the film in the step (2) and uniformly casting, and then putting the film forming solution into a constant temperature and humidity box for drying for 5-10 hours to obtain a film II;
(4) repeating the step (1) again to obtain a third starch film-forming solution; pouring the film forming solution on the surface of the second film in the step (3) and uniformly casting, and drying in a constant temperature and humidity cabinet for 12-20 hours to obtain a third film;
(5) taking down the film III prepared in the step (4), heating at the temperature of 80-140 ℃ for 1-3 h, and finally taking out to balance at room temperature to obtain the hydrophobic modified starch film;
wherein the temperature in the constant temperature and humidity chamber in the steps (2) - (4) is 15-45 ℃, and the relative humidity is 40-80%.
In one or more embodiments, the starch in step (1) is one or more of native starch, or one or more of destructured starch.
Specifically, the native starch is tapioca starch, potato starch, wheat starch or corn starch; the modified starch is hydroxypropyl corn modified starch, carboxymethyl starch, esterified starch, oxidized starch, acid modified starch, etherified starch, cross-linked starch, cationic starch, grafted starch or dialdehyde starch.
In one or more embodiments, the plasticizer in step (1) is xylitol, sorbitol, mannitol, propylene glycol, glycerol, fructose, sucrose, or triacetin.
In one or more embodiments, the homogenizing means in step (1) is any method in the prior art, such as a high-speed stirring method, wherein the stirring speed is 10000-20000 rpm, and the stirring time is 2-10 min.
In one or more embodiments, the alkyl ketene dimer is added in step (1) in an amount of 4% to 20% by weight of dry starch.
In one or more embodiments, the material of the flat plate in step (2) is any one of polystyrene, polytetrafluoroethylene, polyvinyl chloride or glass.
In one or more embodiments, it is preferable that the casting amount of the film-forming solution in the steps (2) and (4) is 0.3 to 0.6g/cm2(ii) a The casting amount of the film forming liquid in the step (3) is 0.5-0.8 g/cm2。
The third purpose of the invention is to apply the hydrophobic modified starch film obtained by the preparation method in medicines, foods or cosmetics. Specifically, the obtained hydrophobically modified starch film can be used for coating medicines, foods or cosmetics.
A fourth object of the invention is the use of an alkyl ketene dimer in the preparation of a hydrophobically modified starch film. The alkyl ketene dimer is waxy solid, contains a lactone ring with higher chemical activity in the molecular structure, can be subjected to esterification reaction with hydroxyl in a starch material to generate beta-ketoester, and achieves the hydrophobic purpose by converting the hydroxyl which is easy to be hydrophilic into an ester group.
Compared with the prior art, the novel hydrophobically modified starch film is prepared by adopting a layered multiple casting process, adopts a three-layer structure which is hydrophobically modified by alkyl ketene dimer and has homogeneous and heterogeneous self-reinforcing characteristics, has hydrophobic outer layer and excellent mechanical property provided by inner layer, reduces the hydrophilicity of the starch film while keeping the excellent performance of the starch film to the maximum extent, and improves the hydrophobic performance of the starch film.
For a better understanding and practice, the invention is described in detail below with reference to the accompanying drawings.
Drawings
FIG. 1: the invention relates to a flow chart of preparation steps of a hydrophobically modified starch film.
Detailed Description
The invention aims to solve the problem that the mechanical property of a film material is reduced due to the phase separation action generated by directly blending a hydrophobic substance and starch, and provides a novel hydrophobically modified starch film and a preparation method thereof. The film is prepared by layering and multiple tape casting, can maintain the excellent performance of the starch film to the maximum extent, reduce the hydrophilicity of the starch film and improve the hydrophobic performance of the starch film.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the first purpose of the invention is to provide a novel hydrophobically modified starch film, and the added modifier is alkyl ketene dimer.
In one or more embodiments, the hydrophobically modified starch film comprises dry starch, water, plasticizers, and the like in a common starch film; or alkyl ketene dimer is added in the preparation method of the common starch film to achieve the aim of hydrophobicity.
A second object of the present invention is to provide a method for preparing the hydrophobically modified starch film (as shown in fig. 1), comprising the steps of:
(1) mixing starch with water to prepare a suspension with the concentration of 3-8 wt%; adding a plasticizer which is 20-40% of the weight of the dry starch, and continuously stirring in a constant-temperature water bath kettle at 90-95 ℃ until the starch is fully gelatinized; reducing the temperature of the water bath to 40-70 ℃ while keeping stirring, adding alkyl ketene dimer, and fully homogenizing the solution after the alkyl ketene dimer is completely melted to obtain a starch film forming solution I;
(2) casting the starch film-forming solution I prepared in the step (1) on a flat plate, and then placing the flat plate in a constant temperature and humidity cabinet for drying for 2-5 hours to obtain a film I tightly attached to the surface of the flat plate;
(3) repeating the step (1) again without adding alkyl ketene dimer to obtain a starch film-forming solution II; pouring the film forming solution on the surface of the film in the step (2) and uniformly casting, and then putting the film forming solution into a constant temperature and humidity box for drying for 5-10 hours to obtain a film II;
(4) repeating the step (1) again to obtain a third starch film-forming solution; pouring the film forming solution on the surface of the second film in the step (3) and uniformly casting, and drying in a constant temperature and humidity cabinet for 12-20 hours to obtain a third film;
(5) taking down the film III prepared in the step (4), heating at the temperature of 80-140 ℃ for 1-3 h, and finally taking out to balance at room temperature to obtain the hydrophobic modified starch film;
wherein the temperature in the constant temperature and humidity chamber in the steps (2) - (4) is 15-45 ℃, and the relative humidity is 40-80%.
In one or more embodiments, the starch in step (1) is one or more of native starch, or is one or more of destructured starch.
Specifically, the native starch is tapioca starch, potato starch, wheat starch or corn starch; the modified starch is hydroxypropyl corn modified starch, carboxymethyl starch, esterified starch, oxidized starch, acid modified starch, etherified starch, cross-linked starch, cationic starch, grafted starch or dialdehyde starch.
In one or more embodiments, the plasticizer in step (1) is xylitol, sorbitol, mannitol, propylene glycol, glycerol, fructose, sucrose, or triacetin.
In one or more embodiments, the homogenizing means in step (1) is any method in the prior art, such as a high-speed stirring method, the stirring speed is 10000-20000 rpm, and the stirring time is 2-10 min.
In one or more embodiments, the alkyl ketene dimer is added in step (1) in an amount of 4% to 20% by weight of the dry starch.
In one or more embodiments, the material of the flat plate in step (2) is any one of polystyrene, polytetrafluoroethylene, polyvinyl chloride, or glass.
In one or more embodiments, the casting amount of the film forming solution in the steps (2) and (4) is preferably 0.3-0.6 g/cm 2; the casting amount of the film forming liquid in the step (3) is 0.5-0.8 g/cm 2.
The third purpose of the invention is to apply the hydrophobic modified starch film obtained by the preparation method in medicines, foods or cosmetics. Specifically, the obtained hydrophobically modified starch film can be used for coating medicines, foods or cosmetics.
A fourth object of the invention is the use of an alkyl ketene dimer in the preparation of a hydrophobically modified starch film. The alkyl ketene dimer is waxy solid, contains a lactone ring with higher chemical activity in the molecular structure, can be subjected to esterification reaction with hydroxyl in a starch material to generate beta-ketoester, and achieves the hydrophobic purpose by converting the hydroxyl which is easy to be hydrophilic into an ester group.
All materials, reagents and equipment selected for use in the present invention are well known in the art, but do not limit the practice of the invention, and other reagents and equipment well known in the art may be suitable for use in the practice of the following embodiments of the invention.
Example 1
A hydrophobically modified starch film is prepared by the following method:
(1) mixing common corn starch (sold in market) with water to prepare a suspension with the concentration of 4 wt%, adding a proper amount of glycerol (20 wt% of the dry weight of the starch) and continuously stirring in a constant-temperature water bath kettle at 95 ℃ until the starch is fully gelatinized; maintaining the stirring while reducing the temperature of the water bath to 50 ℃, adding alkyl ketene dimer (8 wt% of starch dry weight) (Kull chemical Co., Ltd.), and after completely melting, stirring the solution at 10000rpm for 3 min;
(2) casting 30g of the film-forming solution prepared in the step (1) on a polytetrafluoroethylene (Shanghai rampart solid apparatus Co., Ltd.) flat plate with the diameter of 11cm, and then placing the flat plate on a constant temperature and humidity box with the relative humidity of 50% and the temperature of 20 ℃ for drying for 3.5h to form a film and enable the film to be tightly attached to the surface of the flat plate;
(3) preparing the starch film-forming solution obtained in the step (1) again, but not adding alkyl ketene dimer; pouring 40g of the film forming liquid on the surface of the film in the step (2), uniformly casting, and drying in a constant temperature and humidity box with relative humidity of 50% and temperature of 20 ℃ for 8 hours to form a film;
(4) preparing the film forming solution in the step (1) again, pouring 30g of the film forming solution on the surface of the film in the step (3), uniformly casting, and drying in a constant temperature and humidity box with relative humidity of 50% and temperature of 20 ℃ for 15h to form a film;
(5) and (4) taking down the film prepared in the step (4), heating the film in an oven at a high temperature of 120 ℃ for 3 hours, and finally taking out the film and balancing the film at room temperature.
Example 2
A hydrophobically modified starch film is prepared by the following method:
(1) mixing potato starch (commercially available) with water to obtain a suspension with a concentration of 6 wt%, adding appropriate amount of glycerol (30 wt% of the dry weight of the starch), and continuously stirring in a water bath kettle at a constant temperature of 95 ℃ until the starch is fully gelatinized; keeping stirring and reducing the temperature of the water bath to 60 ℃, adding alkyl ketene dimer (12 wt% of the dry weight of starch), and stirring the solution for 2min at 14000rpm after the alkyl ketene dimer is completely melted;
(2) casting 30g of the film-forming solution prepared in the step (1) on a polystyrene (Shanghai Hill science and instruments Co., Ltd.) flat plate with the diameter of 11cm, and then placing the flat plate in a constant-temperature and constant-humidity box with the relative humidity of 40% and the temperature of 25 ℃ for drying for 2.5h to form a film and enable the film to be tightly attached to the surface of the flat plate;
(3) preparing the starch film-forming solution obtained in the step (1) again, but not adding alkyl ketene dimer; pouring 40g of the film forming liquid on the surface of the film in the step (2), uniformly casting, and then putting the film forming liquid into a constant temperature and humidity box with the relative humidity of 40% and the temperature of 25 ℃ for drying for 6.5 hours to form a film;
(4) preparing the film forming solution in the step (1) again, pouring 30g of the film forming solution on the surface of the film in the step (3), uniformly casting, and drying in a constant temperature and humidity box with relative humidity of 40% and temperature of 25 ℃ for 18h to form a film;
(5) and (4) taking down the film prepared in the step (4), heating the film in an oven at a high temperature of 140 ℃ for 1h, and finally taking out the film and balancing the film at room temperature.
Example 3
A hydrophobically modified starch film is prepared by the following method:
(1) mixing high-amylose hydroxypropyl starch with water to prepare a suspension with the concentration of 7 wt%, adding a proper amount of mannitol (24 wt% of the dry weight of the starch) and continuously stirring in a water bath kettle at the constant temperature of 95 ℃ until the starch is fully gelatinized; keeping stirring and reducing the temperature of the water bath to 65 ℃, adding alkyl ketene dimer (16 wt% of starch dry weight), and stirring the solution for 1min at 15000rpm after complete melting;
(2) taking 35g of the film forming solution prepared in the step (1) to flow and coat on a polyvinyl chloride (Hangzhou Leqi experiment equipment Co., Ltd.) flat plate with the diameter of 11cm, and then placing the flat plate in a constant temperature and humidity box with the relative humidity of 65% and the temperature of 40 ℃ to dry for 2 hours so as to form a film and cling to the surface of the flat plate;
(3) preparing the starch film-forming solution obtained in the step (1) again, but not adding alkyl ketene dimer; pouring 40g of the film forming liquid on the surface of the film in the step (2), uniformly casting, and drying in a constant temperature and humidity box with relative humidity of 65% and temperature of 40 ℃ for 5.5h to form a film;
(4) preparing the film forming solution in the step (1) again, pouring 30g of the film forming solution on the surface of the film in the step (3), uniformly casting, and drying in a constant temperature and humidity box with relative humidity of 65% and temperature of 40 ℃ for 13h to form a film;
(5) and (4) taking down the film prepared in the step (4), heating the film in an oven at a high temperature of 130 ℃ for 2 hours, and finally taking out the film and balancing the film at room temperature.
Example 4
A hydrophobically modified starch film is prepared by the following method:
(1) mixing carboxymethyl starch with water to prepare a suspension with the concentration of 5 wt%, adding a proper amount of propylene glycol (35 wt% of the dry weight of the starch) and continuously stirring in a water bath kettle at the constant temperature of 95 ℃ until the starch is fully gelatinized; keeping stirring and reducing the temperature of the water bath to 65 ℃, adding alkyl ketene dimer (20 wt% of the dry weight of starch), and stirring the solution for 1min at 15000rpm after the alkyl ketene dimer is completely melted;
(2) taking 35g of the film forming solution prepared in the step (1) to carry out curtain coating on a polytetrafluoroethylene flat plate with the diameter of 11cm, and then placing the flat plate in a constant temperature and humidity box with the relative humidity of 55% and the temperature of 50 ℃ for drying for 2 hours to form a film and enable the film to be tightly attached to the surface of the flat plate;
(3) preparing the starch film-forming solution obtained in the step (1) again, but not adding alkyl ketene dimer; pouring 40g of the film forming liquid on the surface of the film in the step (2), uniformly casting, and drying in a constant temperature and humidity box with relative humidity of 55% and temperature of 50 ℃ for 5 hours to form a film;
(4) preparing the film forming solution in the step (1) again, pouring 30g of the film forming solution on the surface of the film in the step (3), uniformly casting, and drying in a constant temperature and humidity box with relative humidity of 55% and temperature of 50 ℃ for 12 hours to form a film;
(5) and (4) taking down the film prepared in the step (4), heating the film in an oven at a high temperature of 130 ℃ for 2 hours, and finally taking out the film and balancing the film at room temperature.
Comparative example 1
A starch film is prepared by the following method:
mixing common corn starch with water to prepare a suspension with the concentration of 6 wt%, adding a proper amount of glycerol (20 wt% of the dry weight of the starch), and continuously stirring in a constant-temperature water bath kettle at 95 ℃ until the starch is fully gelatinized; taking 35g of the film-forming solution, casting the film-forming solution on a polytetrafluoroethylene flat plate with the diameter of 11cm, and then placing the film-forming solution in a constant temperature and humidity box with the relative humidity of 55% and the temperature of 50 ℃ for drying for 15h to obtain a pure starch film without adding alkyl ketene dimer.
Comparative example 2
A starch film is prepared by the following method:
mixing common corn starch with water to prepare a suspension with the concentration of 6 wt%, adding a proper amount of glycerol (20 wt% of the dry weight of the starch), and continuously stirring in a constant-temperature water bath kettle at 95 ℃ until the starch is fully gelatinized; keeping stirring and reducing the temperature of the water bath to 65 ℃, adding alkyl ketene dimer (8 wt% of the dry weight of starch), stirring the solution for 1min at 15000rpm after the solution is completely melted to obtain a film forming solution, taking 35g of the solution to be cast on a polytetrafluoroethylene flat plate with the diameter of 11cm, then placing the flat plate in a constant temperature and humidity box with the relative humidity of 55% and the temperature of 50 ℃ for drying for 15h to volatilize water, and then placing the flat plate in a high temperature and humidity box with the temperature of 120 ℃ for heating for 3h to prepare the direct blending film.
Test example
The method for testing the film strength in the embodiment is as follows: according to GB13022-91, before testing, film samples were uniformly equilibrated for three days in a constant temperature and humidity cabinet at 25 ℃ and 53% relative humidity. For the test, a smooth flat film sample was cut into dumbbell-shaped test specimens (35 mm. times.2 mm) using a special cutter. The test was performed using an INSTRONT 5566 universal materials tester (instron corporation, usa) with initial tension clamp spacing of 25mm, a load cell sensitivity of 0.1N, set tension speed of 5mm/min, and automatic homing of the instrument clamps after the sample strip had been tensile broken. Each sample was tested in 7 replicates and the Elongation At Break (EAB) and Tensile Strength (TS) of the samples were recorded.
The test method for elongation at break in this example was: same as above
The test method of the water absorption rate in the embodiment is as follows: according to GB/T1034-2008, the sample film is cut into a square shape with the length and the width of 61 +/-1 mm, and then is put into an oven at 50.0 +/-2.0 ℃ to be dried to constant weight (the mass change is within +/-0.1 mg). The dried samples were placed in a constant temperature and humidity cabinet at 23 ℃ and 50% relative humidity, and after 24 hours, each sample was weighed (to the nearest 0.1 mg). Each sample was assayed in triplicate and the water absorption mass fraction of the sample relative to the initial mass was calculated according to equations 2-3:
c＝(m2-m1)/m1×100％ (2-3)
wherein m is2And m1The mass of the sample after and before moisture absorption, respectively.
The test method of the surface contact angle in the present embodiment is as follows: and (3) dripping 3 mu L of deionized water on the surface of the sample film by using a DCA 20 contact angle instrument, photographing the water drop by using a digital camera at 0s just after the water drop falls and 60s after the water drop contacts, selecting a three-phase contact point, a vertex, an upper left point and an upper right point of the water drop by using a manual measurement method to perform contour selection, and then automatically calculating the angle between a solid-liquid-gas three-phase tangent line and a liquid-solid contact baseline as a static contact angle. And 5 measuring points are selected for each sample to be tested, and finally the contact angle value of the surface of the sample is obtained.
The main properties of the starch films of the examples and the comparative examples are as follows:
as can be seen from the above table, compared to comparative example 1, the starch films of examples 1-4 and comparative example 2 added with different amounts of alkyl ketene dimers, the water absorption of the film was significantly reduced, and the surface contact angle was significantly increased, because the alkyl ketene dimers were esterified with the hydroxyl groups of the starch, and the hydrophobicity of the starch film was improved; compared with the direct blending casting of the comparative example 2, the novel starch film prepared by the layering multiple casting method has stronger mechanical property, the tensile strength and the elongation at break of the novel starch film have obvious changes with a pure starch film, the water absorption rate and the surface contact angle have little difference, and the hydrophobic property can be obviously improved while the mechanical property of the starch film is kept.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A novel hydrophobically modified starch film is characterized in that the added modifier is alkyl ketene dimer.
2. The method of making a hydrophobically modified starch film in accordance with claim 1, comprising the steps of:
(1) mixing starch with water to prepare a suspension with the concentration of 3-8 wt%; adding a plasticizer which is 20-40% of the weight of the dry starch, and continuously stirring in a constant-temperature water bath kettle at 90-95 ℃ until the starch is fully gelatinized; reducing the temperature of the water bath to 40-70 ℃ while keeping stirring, adding alkyl ketene dimer, and fully homogenizing the solution after the alkyl ketene dimer is completely melted to obtain a starch film forming solution I;
(2) casting the starch film-forming solution I prepared in the step (1) on a flat plate, and then placing the flat plate in a constant temperature and humidity cabinet for drying for 2-5 hours to obtain a film I tightly attached to the surface of the flat plate;
(3) repeating the step (1) again without adding alkyl ketene dimer to obtain a starch film-forming solution II; pouring the film forming solution on the surface of the film in the step (2) and uniformly casting, and then putting the film forming solution into a constant temperature and humidity box for drying for 5-10 hours to obtain a film II;
(4) repeating the step (1) again to obtain a third starch film-forming solution; pouring the film forming solution on the surface of the second film in the step (3) and uniformly casting, and drying in a constant temperature and humidity cabinet for 12-20 hours to obtain a third film;
(5) taking down the film III prepared in the step (4), heating at the temperature of 80-140 ℃ for 1-3 h, and finally taking out to balance at room temperature to obtain the hydrophobic modified starch film;
wherein the temperature in the constant temperature and humidity chamber in the steps (2) - (4) is 15-45 ℃, and the relative humidity is 40-80%.
3. The method according to claim 2, wherein the starch in step (1) is one or more of native starch or one or more of modified starch.
4. The method of claim 3, wherein the native starch is tapioca starch, potato starch, wheat starch, or corn starch; the modified starch is hydroxypropyl corn modified starch, carboxymethyl starch, esterified starch, oxidized starch, acid modified starch, etherified starch, cross-linked starch, cationic starch, grafted starch or dialdehyde starch.
5. The method according to claim 2, wherein the plasticizer in the step (1) is xylitol, sorbitol, mannitol, propylene glycol, glycerin, fructose, sucrose or triacetin.
6. The method according to claim 2, wherein the alkyl ketene dimer is added in step (1) in an amount of 4 to 20% by weight based on the dry starch.
7. The method according to claim 2, wherein the flat plate in step (2) is made of polystyrene, polytetrafluoroethylene, polyvinyl chloride or glass.
8. The production method according to claim 2, wherein the casting amount of the film-forming solution in the steps (2) and (4) is 0.3 to 0.6g/cm2(ii) a The casting amount of the film forming liquid in the step (3) is 0.5-0.8 g/cm2。
9. Use of a hydrophobically modified starch film obtainable by a process according to any one of claims 2 to 8 in pharmaceuticals, foods or cosmetics.
10. Use of an alkyl ketene dimer in the preparation of a hydrophobically modified starch film.
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| CN202110957156.9A CN114075343B (en) | 2021-08-19 | 2021-08-19 | Hydrophobically modified starch film |
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| CN101230151A (en) * | 2007-12-28 | 2008-07-30 | 北京航空航天大学 | High-fluidity and strong-hydrophobicity starch and preparation method thereof |
| CN101328285A (en) * | 2008-01-25 | 2008-12-24 | 陕西科技大学 | Preparation of hydrophobical thermoplastic starch |
| CN103302708A (en) * | 2013-05-08 | 2013-09-18 | 广东省宜华木业股份有限公司 | Preparation method of novel hydrophobic wood |
| CN103757980A (en) * | 2014-01-03 | 2014-04-30 | 金华盛纸业（苏州工业园区）有限公司 | Latex for papermaking, preparation method and coating containing latex for papermaking |
| US20200048436A1 (en) * | 2018-08-10 | 2020-02-13 | Green World Biotech Materials Co.,Ltd. | Hydrophobic thermoplastic starch composite and method for manufacturing the same |
| CN111621046A (en) * | 2020-06-09 | 2020-09-04 | 施塔希(绍兴)新材料有限公司 | Waterproof starch film with biodegradable polyurethane as coating and preparation method thereof |
| CN112790456A (en) * | 2020-12-29 | 2021-05-14 | 无锡市圣华盾医疗科技有限公司 | Waterproof moisture-permeable medical protective clothing and manufacturing method thereof |
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| CN101230151A (en) * | 2007-12-28 | 2008-07-30 | 北京航空航天大学 | High-fluidity and strong-hydrophobicity starch and preparation method thereof |
| CN101328285A (en) * | 2008-01-25 | 2008-12-24 | 陕西科技大学 | Preparation of hydrophobical thermoplastic starch |
| CN103302708A (en) * | 2013-05-08 | 2013-09-18 | 广东省宜华木业股份有限公司 | Preparation method of novel hydrophobic wood |
| CN103757980A (en) * | 2014-01-03 | 2014-04-30 | 金华盛纸业（苏州工业园区）有限公司 | Latex for papermaking, preparation method and coating containing latex for papermaking |
| US20200048436A1 (en) * | 2018-08-10 | 2020-02-13 | Green World Biotech Materials Co.,Ltd. | Hydrophobic thermoplastic starch composite and method for manufacturing the same |
| CN111621046A (en) * | 2020-06-09 | 2020-09-04 | 施塔希(绍兴)新材料有限公司 | Waterproof starch film with biodegradable polyurethane as coating and preparation method thereof |
| CN112790456A (en) * | 2020-12-29 | 2021-05-14 | 无锡市圣华盾医疗科技有限公司 | Waterproof moisture-permeable medical protective clothing and manufacturing method thereof |
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| CN114075343B (en) | 2023-07-07 |
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