CN115322447B - A kind of processing method of starch-based toughened composite material - Google Patents

Abstract

The invention relates to a processing method of a starch-based toughened composite material, belonging to the field of starch biomaterials. The novel starch-based composite material is prepared by taking starch as a base material and combining multi-element synergistic toughening processing. The method has simple and controllable operation and low production cost, and the starch-based toughened composite material prepared by the method has the tensile strength of not less than 22MPa, the elongation at break of not less than 520 percent and the notch impact strength of not less than 42kJ/m ² The 90-day biodegradation rate is not lower than 90 percent, and the composite material can be widely applied to a plurality of fields such as development of disposable tableware, daily chemical containers, medical appliances and the like, and has very wide market prospect.

Description

A kind of processing method of starch-based toughened composite material

technical field

The invention relates to a processing method of a starch-based toughened composite material, which belongs to the field of starch biomaterials.

Background technique

Traditional petroleum-based plastics are widely used. While consuming a large amount of petroleum resources, due to their stable physical and chemical properties, they are difficult to degrade and recycle, and release a large amount of carbon dioxide when burned, causing white pollution and greenhouse effect. According to data from the National Bureau of Statistics, the recycling rate of waste plastics in my country only accounted for 23.09% in 2019, and most waste plastics need to be disposed of by incineration or landfill. How to deal with these plastic wastes has become a global problem, so there is an urgent need to develop green polymer materials, which do not use toxic and harmful substances in the preparation process, and can be degraded in the natural environment after use. With the increasing shortage of petroleum resources and the improvement of public awareness of environmental protection, the research and development of biodegradable plastics has attracted widespread attention and attention in recent years. On the one hand, biodegradable polymers solve the problem of environmental pollution caused by plastic waste that has plagued people for a long time, and on the other hand, they also alleviate the contradiction of the shortage of petroleum resources.

Due to its large reserves, low cost, and renewable advantages, starch has attracted worldwide attention in the development of degradable materials and has great potential for development. Companies in Japan, the United States, and Italy claim to have successfully developed all-starch thermoplastics and have formed large-scale production and sales. However, the development and utilization of starch-based materials in my country is still in its infancy. Compared with the international advanced level, there are still obvious gaps in product performance, manufacturing costs, key technologies and industrialization scale. On the other hand, compared with traditional plastics, starch-based degradable plastics have performance defects such as brittleness, insufficient toughness, poor tensile and impact resistance, poor heat resistance, low melt strength, and hygroscopicity, which limit their application in various fields. application. In summary, in order to improve the shortcomings of starch-based materials such as insufficient mechanical properties and poor water resistance, it is necessary to develop a processing method for impact-resistant and tensile-resistant starch-based toughened composite materials.

Contents of the invention

technical problem:

A method for processing an impact-resistant and tensile-resistant starch-based toughened composite material is provided. The tensile strength of the starch-based toughened composite material obtained by the method is not lower than 22 MPa, and the elongation at break is not lower than 520%. The notched impact strength is not lower than 42kJ/m ² , and the 90-day biodegradation rate is not lower than 90%.

Technical solutions:

The first object of the present invention is to provide a kind of processing method of starch-based toughened composite material, comprising the following steps:

(1) Derivatizing the core-shell structure elastomer and the interface modifier under heating conditions to obtain an activated core-shell structure elastomer;

(2) According to the parts by weight of each substance, mix 130 parts of starch, 10-30 parts of activated core-shell structure elastomer, 2-5 parts of etherifying agent and 2-5 parts of plasticizer, and adjust to the moisture content 5-8wt%, hot-pressed at 100-130°C to obtain a starch-based toughened composite material; wherein, the inner core of the core-shell elastic body is an elastomer, and the outer shell is a high glassy polymer; the starch The amylose content in it is not less than 40%.

As an embodiment of the present invention, in step (2), the amylose content in the starch is 50-75%.

As an embodiment of the present invention, in step (1), the weight ratio of the core-shell structure elastomer to the interface modifier is (30-40):1. Preferably, the weight ratio of the core-shell structure elastomer to the interface modifier is (33-40):1.

As an embodiment of the present invention, in step (1), derivatization treatment: the temperature is 75-90° C., and the time is 0.5-1 h.

As an embodiment of the present invention, the elastomer core material of the core-shell structure elastomer includes at least one of styrene-butadiene rubber, ethylene-propylene rubber, nitrile rubber, polyisobutylene and acrylate copolymers. Preferably, the elastic core material of the core-shell elastic body is styrene-butadiene rubber or acrylic copolymer.

As an embodiment of the present invention, the high glassy polymer shell material of the core-shell structure elastomer includes styrene, methacrylic acid, vinyl, chlorinated polyethylene, and methacrylate copolymers. one or more.

As an embodiment of the present invention, the core-shell elastomer is prepared by a stepwise emulsion method.

As an embodiment of the present invention, a distributed emulsion method is used to mix the polymer and the reaction reagent for graft copolymerization: the temperature is 50-80°C, and the reaction time is 2-3h; the secondary grafting temperature is 70-90°C, and the reaction time is 1 ~3h; Coagulation, centrifugation, dehydration and drying to obtain the core-shell structure elastomer.

As an embodiment of the present invention, the interface modifier includes acid anhydrides, carboxyls, epoxy groups, isocyanates, glycidyl acrylate, polyacrylate carboxyls, imides and oxazolines at least one of the Preferably, the interface modifier is at least one of succinic anhydride, acetic anhydride, maleic anhydride, maleic anhydride and glycidyl acrylate.

As an embodiment of the present invention, in step (2), the starch includes at least one of corn starch, rice starch, wheat starch, tapioca starch, sweet potato starch, potato starch and mung bean starch.

As an embodiment of the present invention, in step (2), the etherification agent includes but not limited to propylene oxide, ethylene oxide, epichlorohydrin, aminotrimethane hydrochloride, epichlorohydrin and At least one of 2-chloroethanol.

As an embodiment of the present invention, in step (2), the plasticizer includes but not limited to water, glycerin, sorbitol, ethylene glycol, mannitol, erythritol, polyvinyl alcohol and thiourea at least one of .

As an embodiment of the present invention, in step (2), the hot pressing temperature is 120-130°C.

The second object of the present invention is to provide a starch-based toughened composite material, which is obtained by the aforementioned method. The tensile strength of the starch-based toughened composite material is not lower than 22MPa, and the elongation at break is not lower than 520 %, the notched impact strength is not lower than 42kJ/m ² , and the 90-day biodegradation rate is not lower than 90%.

The third object of the present invention is to provide a packaging product containing the aforementioned starch-based toughened composite material.

The fourth object of the present invention is to provide the application of the aforementioned starch-based toughened composite material in the preparation of food, textiles, daily chemicals or medical products.

Beneficial effect:

1. The present invention mainly uses starch as the base material, and successfully prepares high bio-based content by adding a specific proportion of derivatized core-shell structure elastomer, etherification agent and plasticizer, combined with multi-component synergistic toughening processing technology , high strength, high toughness, impact resistance, tensile resistance, and easy biodegradable starch-based toughened composite materials. The tensile strength of the starch-based toughened composite material prepared by this method is not less than 22MPa, the elongation at break is not less than 520%, the notched impact strength is not less than 42kJ/m ² , and the biodegradation rate in 90 days is not less than 90%. %, can be used to produce disposable membranes, sheets, pellets, products such as: hard tableware, daily chemical containers, automotive interiors, widely used in textiles, food, daily chemical, transportation, medical and other fields, the market prospect broad.

2. The present invention uses potato starch, grain starch, and bean starch as main raw materials, and the raw materials have wide sources, low prices, and are not restricted by production areas and seasons.

3. The processing method of the present invention has simple operation, controllable flow of each link, adopts clean production process, and the production process is green and pollution-free, and no three industrial wastes are generated.

4. The invention uses abundant starch resources to develop environmentally friendly and recyclable degradable materials, which is in line with the national strategic industry development plan, and is of great significance for solving the oil crisis and plastic pollution, and building a resource-saving and environment-friendly society.

Detailed ways

Performance test method:

Tensile strength : analyze with reference to the national standard GB/T 1040.2-2006 Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics.

Elongation at break : analyzed with reference to the national standard GB/T 1040.3-2006 Determination of tensile properties of plastics Part 3: Plastics-test conditions for tensile properties testing.

Notched impact strength : analyze according to the test conditions of the national standard GB/T 1843-2008 Determination of plastic Izod impact strength, and measure the impact resistance of the material.

90-day biodegradation rate : With reference to the national standard GB/T19277.1-2011 material biodegradation performance test under controlled composting conditions, the final biodegradation rate is determined by measuring the amount of carbon dioxide emitted by the material as an organic compound under controlled composting conditions. Aerobic biodegradability and its degree of disintegration.

Example 1

A kind of preparation technology of starch-based toughened composite material, adopts following steps:

(1) The core-shell structure elastomer MBS (styrene-butadiene rubber is the core, methyl methacrylate is the shell; the elastomer models are B521, M848, Korea LG Chemical; BTA717, Shenzhen Tianyue Chemical Co., Ltd.) and succinic anhydride Mix well at 80°C for 1 hour to derivatize the surface of the core-shell elastomer MBS to obtain an activated core-shell elastomer; wherein the weight ratio of the core-shell elastomer MBS to succinic anhydride is 40:1 ;

(2) According to the parts by weight of each substance, mix 130 parts of corn starch (52% of amylose), 20 parts of activated core-shell structure elastomer, 3 parts of propylene oxide and 4 parts of glycerin, and adjust to the moisture content The content is 6wt%, and it is hot-pressed at 120°C to obtain a starch-based toughened composite material.

After testing, the target product obtained in Example 1—the starch-based toughened composite material has a tensile strength of 28 MPa, an elongation at break of 560%, a notched impact strength of 49 kJ/m ² , and a 90-day biodegradation rate of 95%.

Example 2

A kind of preparation technology of starch-based toughened composite material, adopts following steps:

(1) The core-shell structure elastomer MBS (styrene-butadiene rubber as the core and methyl methacrylate as the shell; the elastomer models are B521, M848, Korean LG Chemical; M-511, Japan Zhongyuan Chemical Industry Co., Ltd.; BTA717 , Shenzhen Tianyue Chemical Co., Ltd.) and maleic anhydride at 85°C for 0.5h to derivatize the surface of the core-shell elastomer MBS to obtain an activated core-shell elastomer, wherein the core-shell structure The weight ratio of elastomer MBS to maleic anhydride is 33:1;

(2) According to the parts by weight of each substance, 130 parts of potato starch (amylose 75%), 20 parts of activated core-shell structure elastomer, 4 parts of epichlorohydrin and 5 parts of sorbitol are mixed uniformly, and adjusted The moisture content is 8wt%, and hot-pressed at 130° C. to obtain a starch-based toughened composite material.

After testing, the target product obtained in Example 2—the starch-based toughened composite material has a tensile strength of 29 MPa, an elongation at break of 540%, a notched impact strength of 46 kJ/m ² , and a 90-day biodegradation rate of 92%.

Example 3

A kind of preparation technology of starch-based toughened composite material, adopts following steps:

(1) Fully mix the core-shell structure elastomer ACR (acrylic ester copolymer as the core, methyl methacrylate as the shell) and glycidyl acrylate at 75°C for 1 hour to clean the surface of the core-shell structure elastomer ACR. Carry out derivatization treatment, obtain activated core-shell structure elastomer, wherein, the weight ratio of core-shell structure elastomer ACR and glycidyl acrylate is 40:1; , methyl methacrylate as the shell): it is prepared by step-by-step emulsion method, and the preparation method refers to "Preparation, Characterization and Impact Resistance of New Core-Shell ACR with Transition Layer" "Preparation of ACR-g-St and Its Effect on PVC Toughening";

(2) According to the parts by weight of each substance, 130 parts of rice starch (amylose 58%), 20 parts of activated core-shell structure elastomer, 3 parts of ethylene oxide and 4 parts of mannitol are mixed uniformly, and adjusted to The water content is 7wt%, and it is hot-pressed at 125° C. to obtain a starch-based toughened composite material.

After testing, the target product obtained in Example 3—the starch-based toughened composite material has a tensile strength of 23 MPa, an elongation at break of 620%, a notched impact strength of 48 kJ/m ² , and a 90-day biodegradation rate of 94%.

Comparative example 1: Effect of addition of activated core-shell structure elastomer on product performance

A preparation process of a starch-based toughened composite material, referring to Example 1, the only difference is that the parts by weight of the activated core-shell structure elastomer in the thermoplastic starch matrix of step (2) are replaced by 0, 5, 10, 40 parts to prepare the corresponding starch-based toughened composite material. The performance results of the product are shown in Table 1.

Table 1 The effect of the amount of activated core-shell structure elastomer added on the performance of the resulting starch-based toughened composite product

Comparative Example 2: Untreated MBS with core-shell structure

A kind of preparation technology of starch-based toughening composite material, with reference to embodiment 1, difference is only: omit step (1), directly adopt untreated core-shell structure elastomer MBS (styrene-butadiene rubber is core, styrene is shell ), that is, in step (2), adopt untreated core-shell structure elastomer MBS (styrene-butadiene rubber is the core, styrene is the shell) to replace the activated core-shell structure elastomer;

After testing, the target product obtained in Comparative Example 2—the starch-based toughened composite material had a tensile strength of 14 MPa, an elongation at break of 120%, a notched impact strength of 22 kJ/m ² , and a 90-day biodegradation rate of 83%.

Comparative Example 3: Using corn starch with lower amylose content

A preparation process of a starch-based toughened composite material. Referring to Example 1, the only difference is that ordinary corn starch (amylose 26%) is replaced by corn starch (amylose 52%).

After testing, the target product obtained in Comparative Example 2—the starch-based toughened composite material had a tensile strength of 12 MPa, an elongation at break of 145%, a notched impact strength of 27 kJ/m ² , and a 90-day biodegradation rate of 66%.

Claims (8)

1. a processing method of starch-based toughened composite material, is characterized in that, comprises the steps: (1) The core-shell structure elastomer and the interface modifier are derivatized under heating conditions to obtain an activated core-shell structure elastomer; the interface modifier includes succinic anhydride, maleic anhydride, acrylic acid shrinkage at least one of glycerides; (2) According to the parts by weight of each substance, mix 130 parts of starch, 10-30 parts of activated core-shell structure elastomer, 2-5 parts of etherifying agent and 2-5 parts of plasticizer, and adjust to the moisture content 5-8wt%, hot-pressed at 100-130°C to obtain a starch-based toughened composite material; wherein, the inner core of the core-shell elastic body is an elastomer, and the outer shell is a high glassy polymer; the starch The amylose content in the mixture is not less than 40%; in the step (1), the weight ratio of the core-shell structure elastomer to the interface modifier is (30-40):1. 2. The processing method according to claim 1, characterized in that, in step (1), the derivatization treatment: the temperature is 75-90° C., and the time is 0.5-1 h. 3. The processing method according to claim 1, wherein the elastomer core material of the core-shell structure elastomer comprises styrene-butadiene rubber, ethylene-propylene rubber, nitrile rubber, polyisobutylene and acrylic ester copolymers at least one of the 4. The processing method according to claim 1, wherein the high glass polymer shell material of the core-shell structure elastomer comprises styrene, methacrylic acid, ethylene, chlorinated polyethylene, methyl One or more of acrylate copolymers. 5. processing method according to claim 1, is characterized in that, in step (2), described etherifying agent comprises propylene oxide, oxyethane, epichlorohydrin, triaminotrimethane hydrochloride, cyclic At least one of oxychloropropane and 2-chloroethanol. 6. A starch-based toughened composite material, characterized in that it is obtained by the method according to any one of claims 1 to 5, the tensile strength of the starch-based toughened composite material is not less than 22MPa, and the fracture The elongation rate is not lower than 520%, the notched impact strength is not lower than 42kJ/m ² , and the 90-day biodegradation rate is not lower than 90%. 7. A packaging product comprising the starch-based toughened composite material of claim 6. 8. The application of the starch-based toughened composite material according to claim 6 in the preparation of food, textiles, daily chemicals or medical supplies.