Application of Polymer Materials in Modern Agricultural Seed Processing

In addition to the requirements of modern agriculture, production, efficiency, and quality, the current trend toward environmental protection and green agriculture has become increasingly fierce. With the progress of society and people's lives are increasingly being raised, people urgently need a more environmentally-friendly and safe living environment. In response to this demand for social development, a number of international regulations have been set up to prohibit and control the use of toxic hydrazine, high residual agricultural chemicals, encourage the development of low toxicity, low residual agricultural chemicals, and natural pesticides. , Fungicides and other biological agents. In addition to the above methods, it is widely accepted internationally to improve the application system of agrochemicals, including the development of agrochemical preparations, the study of optimal doses, and the pretreatment of seeds. The agricultural production can not be separated from the seeds. Many countries have legislation expressly that the seeds must be treated before they can be used. Seed treatment is an important part of the development of modern agriculture. This article will discuss the latest developments in seed processing in modern agricultural production and focus on the role played by helium molecular materials in seed treatment.

1 Seed Treatment Seed treatment is the use of chemical, physical and other methods to treat the seed, in order to reduce the adverse effects of the seeds on their own bacteria and pests on the growth and development of seeds, while preventing the seeds in the soil after the impact of diseases and insect pests. Seed processing has existed since ancient times. The far back can be traced back to ancient Egypt. At the time of ancient Greece and Rome people used the pulp of yam or cypress to soak seeds. By the middle ages people began to use salt water leaching funds: Changzhou Xinbei District Science and Technology Bureau Innovation Fund (030305) ―), Male, Jiangsu Jintanren, Ph.D., Professor I Contact: Gao Guosheng.

Use, efficacy will not be weakened by other components, but should continue to be effective. In addition, the seed treatment must have low cost, high input-output ratio, and easy operation and promotion. These requirements are the most basic and important criteria for judging the quality of seed processing.

1.2 Seed treatment methods Seed processing methods at home and abroad can be summarized as: physical methods, biological methods, chemical methods and the combination of these methods. The physical method is the use of physical methods, such as the use of heating, irradiation, microwave and other methods to destroy the pests that the seeds themselves carry. The biological method refers to the use of beneficial microorganisms (bacteria) to protect the seed, so as to avoid the influence of bacteria during the growth and development of the seed. The chemical method is very popular for its seed treatment. The method is to treat the seeds with agricultural insecticides and fungicides (synthetic or natural). The specific seed treatment methods include physical coating, soaking, mixing, and surface coating. , Physical granulation and other methods, the application of germanium molecular materials is mainly reflected in the chemical treatment of seeds.

2 Application of polymer materials in seed treatment Seed chemical processing includes the compatibility of seed coating agents and the processing technology (mechanical or artificial). The two are inseparable. In addition to the most conventional original physical mixing, liquid seed soaking, such as mixing seeds and insecticides, bactericides and other auxiliary materials such as laterite, or adding seeds to a pharmaceutical agent or soaking in emulsions, a new generation of seed chemistry Processing can be generally divided into: 1SeedDressing: The use of dry and wet polymer film forming agents, wrapped seeds. 2 SeedCoating: The agricultural drug and other ingredients are coated on the surface of the seed using a hydrazine molecular film former. 3 Seed Pelleting: Seeds and other indole molecular materials are mixed and granulated to improve the appearance and shape of seeds for mechanical seeding.

Physical wrapping is the use of physical methods to mechanically mix agrochemical ingredients with other inorganic or organic germanium molecular materials, such as starch-acrylamide superabsorbent, and adhere evenly to the surface of the seed, which has achieved the function of drought resistance. The seed surface treated by this method is generally rough, the treatment layer is thick, and the seed particle size is not. In order to obtain uniform particles, physical granulation is a good method. For example, Burgess et al. use water-insoluble triterpene molecular particles mixed with seeds to obtain seed-treated seed. This method is mainly aimed at small and light particles. Seeds, the use of mechanical methods, the drug and hydrazine molecular materials, inorganic materials mixed granulation, the treated seed particles of uniform size, improve the quality, suitable for mechanical sowing.

Modern seed coating agents are mainly based on liquids, and the seeds are coated. Seed coating formulations include true solutions, emulsions, suspensions containing solid particles, and microcapsule suspensions. Among all the different forms of seed coating agents, the use of terpenoids as film formers is an indispensable and important component of the seed coating products. Because of the choice of helium molecular materials, it determines the compatibility with the drug, the binding properties of the membrane material and the seed, and the control of drug release performance, thereby controlling plant growth. Conventional seed coating film-forming agents include synthetic polymer compounds and natural polymer compounds, the former including polyvinyl acetate, polyethylene/vinyl acetate copolymers, polyvinyl alcohol or copolymers, polyacrylates, polyacrylates, and the like; The latter includes cellulose and its derivatives (such as cellulose acetate, hydroxypropylmethyl cellulose, hydroxypropyl cellulose, ethyl cellulose, methyl cellulose, microcrystalline cellulose). For example, Taylor et al. used polyvinyl alcohol and other plasticizers for preparation of seed coating agents to obtain better results in seed treatment. Dell et al. used microcrystalline cellulose and other biomolecules to formulate an edible and rapidly curable film former for seed treatment. Monsanto uses emulsion polymers such as polyvinyl acetate and polyethylene/vinyl acetate copolymers to treat seeds. When the coating is cured on the seed surface, it can effectively control the release of agricultural active additives. Some of these high molecular compounds are water-soluble and some are oil-soluble. If a water-soluble hydrazine molecule compound is used as a film-forming agent for a seed coating agent, when coating on a seed surface, a long time is required for film formation, the formed film easily falls off in water, and the ability to control the release of active ingredients is poor. If an oil-soluble quinone molecule compound is used as a film-forming agent for a seed coating agent, it is necessary to use an organic solvent. Although the film-forming property and adhesion to the seed are good, the germination rate of the seed is suppressed. At the same time, organic solvents pose a hazard to the environment and users. With the increasing variety and complexity of various additive components (such as various insecticides, fungicides, nutrient elements, plant regulators, etc.) in seed coating agents, traditional film formers lack selectivity and often cause the utilization of the above additives. reduce. If special hydrazine molecular film formers are used, they are difficult to popularize in seed coating agents due to their high manufacturing cost.

3 Research and Development Progress The polymer materials for seed treatment have been gradually developed from petroleum-based materials to natural and functional polymer materials. Among the more common and important types of polymer materials are: polysaccharides, natural polymer materials, indole molecular materials that maintain good membrane properties at low temperatures, hydrazine absorbent materials, temperature-sensitive materials, and comprehensive utilization of natural biological resources. The development of natural germanium molecular materials, etc., in which seed coating agents developed using sustainable biological resources are particularly attractive. For example, Nishiyama uses sodium alginate to wrap the seeds and uses a physical cross-linking method to solidify and form a film on the surface of the seed so as to realize the controlled release of agricultural actives and achieve anti-bacterial effect. Barclay et al. used starch biosynthetic polysaccharides and other additives to produce seed coating agents. Chen et al. used Xanthan gum to formulate wheat seed coating agents with other agricultural actives. Yan et al. used chitosan and chitosan was low. The treatment results of glycans and glucosamine, etc. The treatment results show that this kind of seed coating agent can promote the development of seed roots, resist disease, and increase the yield of wolfberry. In addition, animal proteins such as gelatin can also be used for seeds because of their excellent film-forming properties. Film-forming agents, authors, and others have comprehensively used animal blood resources to develop and manufacture a new type of film former and environmentally-friendly nutritional seed coating agents, which have a good effect in controlling drug release and increasing crop yields. These materials can replace or partially replace conventional petroleum-based polymer materials, which are of great significance for protecting the environment and promoting the sustainable development of agriculture. It can be inferred that with the promotion of the modernization of China's agricultural development and the urgency of developing green, environmentally friendly and efficient agriculture, seed coating agents will increasingly attract people's attention because of their effect on seed growth and the effect of promoting crop yield increase. It will promote the development of the branch of agricultural polymer materials. It is foreseeable that the polymer material in the treatment of the seed coating agent will develop toward the film-forming property, and the seed adhesion performance is good, and at the same time, the functional and environment-friendly bio-cerium molecular material capable of controlling the drug release will be developed.