阅读说明：本技术 一种生物降解材料及其制备方法和应用 (Biodegradable material and preparation method and application thereof ) 是由 何山 张杨 于 2020-12-10 设计创作，主要内容包括：本发明提供了一种生物降解材料及其制备方法和应用,解决了现有技术中的生物降解材料制备条件苛刻,制备的生物降解材料形成的薄膜存在表面粗糙,切开后横截面有孔隙,延展性不好的问题。本发明的生物降解材料,制备效率高,制备工艺简单,不需要高温高压的苛刻条件,节约能耗,降解性能与传统的高温高压法制备得到的生物降解材料无明显差异,适合制备成膜应用到包装材料等领域中,制备的膜15天左右可以完全降解,本发明的生物降解材料,适合制备成膜应用到包装材料等领域中,制备的膜表面更加光滑、韧性和延展性相比传统高温高压条件制备的膜更加优良。(The invention provides a biodegradable material and a preparation method and application thereof, and solves the problems that the preparation conditions of the biodegradable material in the prior art are harsh, the surface of a film formed by the prepared biodegradable material is rough, the cross section after cutting is porous, and the ductility is poor. The biodegradable material disclosed by the invention is high in preparation efficiency, simple in preparation process, free of harsh conditions of high temperature and high pressure, energy-saving, free of obvious difference in degradation performance from the biodegradable material prepared by a traditional high-temperature and high-pressure method, and suitable for preparing a film to be applied to the fields of packaging materials and the like, and the prepared film can be completely degraded within about 15 days.)

1. A biodegradable material is characterized in that the preparation raw materials comprise: agar, alginate and glycerol, wherein the mass ratio of the agar to the alginate to the glycerol is (0.2-0.8): 1: (0.2-0.8).

2. The biodegradable material according to claim 1, wherein the mass ratio of agar, alginate and glycerol is (0.2-0.5): 1: (0.2-0.5).

3. The method for preparing a biodegradable material according to claim 1 or 2, characterized in that it comprises the following steps:

s1: according to the proportion of the biodegradable material, adding the agar, the alginate and the glycerol into water, mixing, and carrying out microwave heating to obtain a mixed liquid;

s2: and (5) drying the mixed liquid obtained in the step (S1) to obtain the biodegradable material.

4. The method according to claim 3, wherein in step S1, the microwave heating power is 60-120 Hz.

5. The method according to claim 3, wherein the microwave heating temperature in step S1 is 60-100 ℃.

6. The method according to claim 3, wherein in step S1, the microwave heating time is 20-40 min.

7. The method according to claim 3, wherein the drying temperature in step S2 is 30-50 ℃.

8. The method according to claim 3, wherein in step S2, the drying time is 10-30 h.

9. A biodegradable film comprising the biodegradable material according to claim 1 or 2 or the biodegradable material prepared by the method according to any one of claims 3 to 8.

Technical Field

The invention belongs to the technical field of environment-friendly materials, and particularly relates to a biodegradable material as well as a preparation method and application thereof.

Background

The negative impact on the environment caused by plastic materials prepared by the traditional petrochemical route is increasingly remarkable, and the environmental pollution caused by plastics promotes the research of degradable polymers.

The degradation of the polymer mainly occurs through the breakage of main chains or side chains, and specifically includes thermal degradation reaction, oxidation reaction, photochemical degradation, radiation chemical degradation and hydration reaction. Degradation of some polymers occurs in biological environments, such as around living cells or tissues, including soils, oceans, rivers and lakes, and also in vivo environments in humans and animals.

A biodegradable polymer is a special type of polymer that can be broken down by bacteria to form, for example, CO after reaching its intended lifetime₂、N₂Water and minerals. These polymers are composed primarily of ester, amide, and ether functional groups.

At present, the biodegradable material is mainly prepared through high-pressure thermal reaction, and the high-pressure thermal reaction conditions are harsh on one hand, and on the other hand, the film formed by the prepared biodegradable material has the problems of rough surface, pores in the cut cross section and poor ductility.

Disclosure of Invention

The present invention is directed to solving at least one of the above problems in the prior art. Therefore, the invention provides a biodegradable material, which aims to solve the problems that the preparation conditions of the biodegradable material in the prior art are harsh, the surface of a film formed by the prepared biodegradable material is rough, the cross section after cutting is porous, and the ductility is poor.

The invention also provides a preparation method of the biodegradable material.

The invention also provides application of the biodegradable material.

The first aspect of the invention provides a biodegradable material, which is prepared from agar, alginate and glycerol, wherein the mass ratio of the agar to the alginate to the glycerol is (0.2-0.8): 1: (0.2-0.8).

Among the above-mentioned raw materials, commercially available alginate can be used as the raw material for the present invention.

According to some embodiments of the present invention, the raw materials for preparing the biodegradable material comprise agar, alginate and glycerol, wherein the mass ratio of the agar to the alginate to the glycerol is (0.2-0.5): 1: (0.2-0.5).

According to one embodiment of the invention, the biodegradable material is prepared from the following raw materials in parts by weight:

agar: 0.5 part by weight of a reaction kettle,

alginate: 1 part of (A) and (B),

glycerol: 0.5 part by weight of a reaction kettle,

water: 100 parts.

The second aspect of the present invention provides a method for preparing the above biodegradable material, comprising the following steps:

s1: according to the proportion of the biodegradable material, adding the agar, the alginate and the glycerol into water, mixing, and carrying out microwave heating to obtain a mixed liquid;

s2: and (5) drying the mixed liquid obtained in the step (S1) to obtain the biodegradable material.

Different from the traditional heating method of heating from outside to inside, the microwave heating method heats the inside and the outside simultaneously. The microwave can uniformly transfer the energy to the inside and outside of the heated material, so that the inside and outside can be uniformly heated. The heating makes the raw materials of the biodegradable film react more completely during preparation, and covalent bonds among molecules are connected more and more densely, so that the mechanical strength of the biodegradable film is obviously improved.

According to some embodiments of the invention, in step S1, the microwave condition has a power of 60 to 120 Hz.

According to some embodiments of the invention, in step S1, the microwave condition has a power of 80-100 Hz.

According to some embodiments of the invention, the power of the microwave condition in step S1 is 100 Hz.

According to some embodiments of the invention, the heating temperature in step S1 is 60-100 ℃.

According to some embodiments of the invention, the heating temperature in step S1 is 80-100 ℃.

According to some embodiments of the invention, the temperature of the heating is 80 ℃ in step S1.

According to some embodiments of the invention, in the step S1, the heating time is 20-40 min.

According to some embodiments of the invention, in step S1, the heating time is 30 min.

According to some embodiments of the invention, the temperature of the drying is 30 to 50 ℃ in step S2.

According to some embodiments of the invention, the temperature of the drying is 45 ℃ in step S2.

According to some embodiments of the invention, in the step S2, the drying temperature is 10-30 h.

According to some embodiments of the invention, the temperature of the drying is 20h in step S2.

In a third aspect of the invention, there is provided a biodegradable film comprising the biodegradable material or prepared by the method.

According to some embodiments of the present invention, the thickness of the biodegradable film is 50 to 150 μm.

According to some embodiments of the present invention, the biodegradable film has a substantially increased ductility without a reduction in biodegradability.

The biodegradable material of the invention has at least the following beneficial effects:

the biodegradable material has high preparation efficiency, simple preparation process, no need of harsh conditions of high temperature and high pressure, energy consumption saving and no obvious difference between the degradation performance and the biodegradable material prepared by the traditional high temperature and high pressure method.

The biodegradable material is suitable for preparing films and applying to the fields of packaging materials and the like, and the prepared films can be completely degraded in about 15 days.

The biodegradable material is suitable for preparing films to be applied to the fields of packaging materials and the like, and the prepared films have smoother surfaces and better toughness and ductility compared with the films prepared under the traditional high-temperature and high-pressure conditions.

Drawings

Fig. 1 is an engineering stress-strain curve of the biodegradable films prepared in example 1 and comparative example 1.

FIG. 2 is a schematic view of the surface micro-topography of the biodegradable film prepared in example 1.

Fig. 3 is a schematic view of the micro-morphology of the biodegradable film prepared in comparative example 1.

Fig. 4 is a schematic view of the edge micro-topography of the biodegradable film prepared in example 1.

Fig. 5 is a schematic view of the edge micro-topography of the biodegradable film prepared in comparative example 1.

Fig. 6 is a schematic contact angle diagram of the biodegradable films prepared in example 1 and comparative example 1.

Detailed Description

The following are specific examples of the present invention, and the technical solutions of the present invention will be further described with reference to the examples, but the present invention is not limited to the examples.

Example 1

The biodegradable film is prepared by the following specific preparation processes:

s1: mixing agar 2.5g, alginate 5g and glycerol 2.5g in water 500mL, heating at 80 deg.C for 30min with 100Hz microwave power in microwave equipment to obtain mixed liquid;

s2: the mixed liquid obtained in step S1 was poured into a tray of 20 cm. times.30 cm, and dried in an oven at 45 ℃ for 20 hours to form a film having a film thickness of 100. mu.m.

Example 2

The biodegradable film is prepared by the following specific preparation processes:

s1: mixing 1g of agar, 5g of alginate and 1g of glycerol in 500mL of water, and heating the mixture for 30min at 80 ℃ in a microwave device by using 100Hz microwave power to obtain a mixed liquid;

s2: the mixed liquid obtained in step S1 was poured into a tray of 20 cm. times.30 cm, and dried in an oven at 45 ℃ for 20 hours to form a film having a film thickness of 100. mu.m.

Example 3

The biodegradable film is prepared by the following specific preparation processes:

s1: mixing 4g of agar, 5g of alginate and 4g of glycerol in 500mL of water, and heating for 30min at 80 ℃ in a microwave device by using 100Hz microwave power to obtain a mixed liquid;

s2: the mixed liquid obtained in step S1 was poured into a tray of 20 cm. times.30 cm, and dried in an oven at 45 ℃ for 20 hours to form a film having a film thickness of 100. mu.m.

Comparative example 1

The biodegradable film is prepared by a traditional high-temperature high-pressure method, and the preparation process comprises the following steps:

s1: mixing agar 2.5g, alginate 5g and glycerol 2.5g in 500mL water, and heating in a high-pressure reaction kettle with pressure of 3bar at 120 deg.C for 30min to obtain mixed liquid;

s2: the mixed liquid obtained in step S1 was poured into a tray of 20 cm. times.30 cm, and dried in an oven at 45 ℃ for 20 hours to form a film having a film thickness of 100. mu.m.

Detection example 1

This example tests the degradation performance of the biodegradable films prepared in example 1 and comparative example 1.

The test method comprises the following steps: the membrane was cut into 25mm by 25mm squares, about 150g, and then soaked in water for 3min and then 96% ethanol for 2 min. After completion of the soaking, the film was dried at room temperature for 16h and weighed for the first time after drying. After weighing, the soil was placed in a container containing 200mg of soil for 30 days. The film was removed every 5 days and the loss of film weight was recorded. The results are shown in Table 1.

TABLE 1 film weight loss test results

As can be seen from table 1, the biodegradability of the film prepared in example 1 was not reduced. The films prepared in comparative example 1 and example 1 were completely degraded in about 15 days.

Detection example 2

The mechanical properties of the biodegradable films prepared in example 1 and comparative example 1 were tested.

The test method comprises the following steps:

and (3) uniaxial tensile test. At room temperature. The equipment is an Instron 5960 universal testing machine, and the capacity range of a weighing sensor is 500N. The loading rate was constant at 5mm/min and the displacement and loading values were recorded from the test system. The length of the specimen between the rigid pinch points is designated 60mm and the sample is fixed on a digital caliper of 20mm width and thickness (about 0.1 mm).

The engineering stress-strain curves of the biodegradable films prepared in example 1 and comparative example 1 are shown with reference to fig. 1.

Fig. 1 reflects the stress-strain relationship during deformation of the film. Wherein the stress strain value represents the brittleness and ductility of the tested material. As can be seen from fig. 1, the preparation method of example 1 significantly improved the mechanical strength of the film, the brittleness of 40MPa was reduced to 37MPa, and the ductility was increased from 0.04% to 0.15% in example 1 as compared to the film of comparative example 1. In example 1, microwave heating was performed simultaneously from the inside to the outside. The microwave simultaneously and uniformly transfers energy to the inner part and the outer part of the heating substance, the inner part and the outer part of the material are simultaneously and uniformly heated, and the heating mode enables the raw materials for preparing the biodegradable film to react more completely and the mutual connection to be more and more dense, so the mechanical strength of the biodegradable film in the embodiment 1 is obviously improved.

Detection example 3

In this example, the microscopic morphology of the biodegradable films prepared in example 1 and comparative example 1 was observed by a Scanning Electron Microscope (SEM) of FEI-F50 type.

The spot size was 2.0 and the voltage was 5.0 kv. The preparation method of the scanning electron microscope sample comprises the following steps: the film was immersed in liquid nitrogen for 2min, and then cut into 5mm × 5mm × 2mm (length × width × thickness) sheets with a scalpel, and then the surface of the sample was coated with a coating layer of about 2nm thickness by platinum sputtering.

The surface micro-topography of the biodegradable film prepared in example 1 is shown in fig. 2, and the micro-topography of the biodegradable film prepared in comparative example 1 is shown in fig. 3. The edge micro-topography of the biodegradable film prepared in example 1 is shown in fig. 4, and the edge micro-topography of the biodegradable film prepared in comparative example 1 is shown in fig. 5.

Comparing fig. 4 and fig. 5, it can be seen that the biodegradable film prepared by the two methods has a large difference in edge. The edges of the biodegradable film prepared in comparative example 1 were observed to have a hollow inner structure with cracks, whereas the edges of the biodegradable film prepared in example 1 were a solid brick structure completely filled without any cracks. Microwave heating has the efficiency of intense micromixing oriented in one direction, and can pulverize the crosslinked material into smaller sizes and align it in one direction. In contrast, the materials processed by the traditional high-temperature and high-pressure method are randomly arranged and have uneven directions, so that the hollow inner edge structure is cracked.

Different from the traditional heating method of heating from outside to inside, the microwave heating method heats the inside and the outside simultaneously. The microwave can uniformly transfer energy to the inner and outer parts of the heated material at the same time, thereby ensuring that the material is uniformly heated at the same time. This heating caused the raw materials of the biodegradable film to react simultaneously during the preparation without delay, so that the biodegradable film prepared in example 1 had a regular and flat surface with clear stripes distributed in one direction. In the traditional heating method, the raw materials of the biodegradable film cannot react simultaneously during preparation due to obvious heat transfer delay caused by heating from outside to inside, and the surface of the prepared biodegradable film is irregular, rough and irregular.

Detection example 4

This example measured the contact angle of the biodegradable films prepared in example 1 and comparative example 1, and the results are shown in fig. 6.

The measuring method comprises the following steps: contact angle measurements were made under ambient conditions (22 ℃) using a standard Ram é Hart 250 goniometer and recorded using DROP Image Advanced V2.8 software. For the fixed drop technique, 5-7 μ L of a water drop was deposited on the substrate and the contact angle was measured within 5 s. For the trapped bubble method, a 6 μ L volume of bubbles was provided at the interface with a pin tumbler (28 gauge, 304 stainless steel Ramsehart). The contact angle in the video was analyzed using Image J (Drop snake analysis) software.

The contact angle of each film was measured 3 times at 0s, 60s and 180 s. The biodegradable film prepared in example 1 was changed from 80.91 ° to 52.36 °. The biodegradable film prepared in comparative example 1 was changed from 52.77 ° to 42.04 °, and the contact angle of the biodegradable film prepared in example 1 was higher than that of the biodegradable film prepared in comparative example 1 in each measurement. Surface roughness has a large effect on the contact angle. The more uniform the surface, the less wetting by surface chemistry and the larger the contact angle.

The present invention has been described in detail with reference to the embodiments, but the present invention is not limited to the embodiments described above, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.