Research on the development and ecology of the hot

Abstract: from the perspective of ecological protection and sustainable development, this paper discusses the importance and necessity of developing ecological packaging materials, summarizes the research status of ecological materials in the world today, including plastic ecological packaging, edible packaging, natural biological packaging, paper packaging, nano plastics, etc., and analyzes the development and research direction of packaging materials in the future

key words: Ecological Research on packaging materials nano plastics

first, the development of packaging materials

the primary stage of packaging materials can be traced back to the recorded history of mankind, when packaging materials were taken from nature. Later, the production of artificial packaging materials, such as paper, glass, metal and so on, provided better raw materials for packaging, and the variety of packaging gradually increased and was widely accepted

the real rise of packaging began with the invention of synthetic material plastic in the 1950s. Plastic has the advantages of light weight, durability, barrier, easy molding, diverse shapes, and less resource and energy consumption. It has largely replaced the packaging materials processed by natural resources, and promoted the emergence of new packaging machinery. It can be said that modern packaging has developed with the development of plastic industry. The 1960s is the turning point of China's plastic products industry from thermosetting plastic products to thermoplastic products. Composite packaging materials developed in the 1970s and 1980s, such as aluminum plastic composites, paper plastic composites, plastic and plastic composites, can replace metal, glass, paper and other packaging materials, improve the barrier, structure and printability of packaging, and make packaging more convenient and safer. Especially in recent years, the production of pet, BOPP, nylon film and aluminized film has effectively promoted the development of plastic packaging materials. Now the development of new technology has promoted the emergence of various emerging packaging

packaging materials gradually occupy an important position in the material industry. According to incomplete statistics, the annual sales of packaging materials in the world is about 50billion US dollars, with more than 5million employees, accounting for 1.5% - 2.3% of the gross national product

however, packaging has a short service life and a large amount of use (for example, in the United States, 150 million tons of municipal waste are generated every year, of which 1/3 is packaging waste. The annual solid waste in Japanese cities is about 50million tons, of which 21million tons are packaging waste) and it is difficult to concentrate, causing serious harm to the urban environment and human body. Environmental problems such as white pollution caused by low recovery rate of plastic film, release of ozone destroying chemicals when burning, and destruction of ecological balance have aroused widespread concern in society

ecological packaging originated from the "our common future" document of the United Nations Commission on environment and development in 1987. It refers to packaging that is harmless to the ecological environment and human health, energy cycle and material recycling, and can promote sustainable development. What ecological materials pursue is not only excellent service performance, but also requires that materials must be compatible with the ecological environment and comfortable in the whole life cycle of manufacturing, use, waste and regeneration. Since the 1990s, ecological packaging materials have made great progress

II. Research on ecological packaging

1 Ecological plastic packaging

Plastic packaging has many advantages. There is no doubt that the quality of plastic packaging plays an important role in packaging materials. At the same time, plastic accounts for a large proportion of packaging waste, about 40%. Its biggest disadvantage is that it is not easy to degrade and cause pollution. At present, the development of new plastic packaging by scientific researchers is mainly biodegradable plastics and chemically degradable plastics

(1) biodegradable plastic ideal biodegradable plastic is a kind of polymer material with excellent performance and can be completely decomposed by environmental microorganisms after being discarded. Paper is a biodegradable material, while synthetic plastics commonly used are non degradable polymer materials. Biodegradable plastic is a new type of high-performance polymer material with the degradability of paper and the high performance of synthetic plastic. The degradation mechanism of biodegradable high molecular (macromolecular) materials has been confirmed: high molecular weight macromolecules are mainly decomposed into small molecular weight fragments by bacteria or their hydrolases, and then further decomposed into carbon dioxide, water and other substances by bacteria. It can be divided into three categories:

polyester produced by microorganisms. It is a microbial fermentation macromolecule. It uses enzymes produced by microorganisms to depolymerize and hydrolyze polyesters that are easy to biodegrade in nature, and then decompose and absorb them to synthesize high molecular compounds, which contain microbial polyesters and microbial polysaccharides. In order to reduce the cost of producing microbial polyester, the research of using plants to synthesize biodegradable plastics is being carried out. The United States and Japan have successively used genetic engineering technology to make some plants directly grow degradable polyester on their branches and leaves. For example, the research team of Michigan State University in the United States has successfully developed synthetic polyester by introducing the genetic genes of the biosynthetic microbial polyester system into plants

natural macromolecules (starch, cellulose, etc.) from plants. The research on the synthesis of biodegradable plastics from starch is very hot at home and abroad. Varna Lambart pharmaceutical company in the United States partially controls the branching degree of starch macromolecular chains by manipulating plant genetic genes, so as to produce biodegradable plastics with cheap starch as raw materials. The company has been promoting the application research of medicinal starch capsules and achieved success. On this basis, they also developed thermoplastic biodegradable plastics with the mixture of starch and biodegradable polymers, and commercialized them under the brand of "novon"

chemical synthesis of polymers. Biodegradable plastics synthesized by chemistry, such as polycaprolactone (PCL), have been used since 1975, but the use is very limited. It is said that 95% of them can be degraded after being buried in the soil for 12 months. PCL and starch blends, PCL and PHBV blends, PCL and nylon 6 blends have been developed, and other biodegradable polyesters based on protein, urea and polysaccharides have also been manufactured, belonging to biodegradable plastics

(2) as a new green packaging material, chemically degradable plastic water-soluble plastic packaging film is widely used in the packaging of various products in Europe, America, Japan and other countries, such as pesticides, fertilizers, pigments, dyes, detergents, water treatment agents, mineral additives, detergents, concrete additives, photographic chemicals and gardening care chemicals. Its main characteristics are: complete degradation, the final products of degradation are CO2 and H2O, which can completely solve the problem of packaging waste treatment; It is safe and convenient to use, avoiding users' direct contact with the packaged goods, and can be used for the packaging of goods harmful to human body; Good mechanical properties, heat sealing and high heat sealing strength; It has anti-counterfeiting function and extends the life cycle of high-quality products

the main raw material of water-soluble packaging film is polyvinyl alcohol with low alcoholysis. Using the film-forming, water-soluble and degradability of polyvinyl alcohol, various additives are added, such as surfactants, plasticizers, anti adhesion agents, etc. In terms of degradation mechanism, polyvinyl alcohol has two degradation characteristics of water and biology. First, it dissolves in water to form glue solution and infiltrates into the soil, which increases the soil's stickiness, permeability and water retention. It is especially suitable for sand soil transformation. PVA in soil can be decomposed by bacteria isolated from soil, Pseudomonas. The symbiotic system composed of at least two kinds of bacteria can degrade polyvinyl alcohol: one is the active bacterium of polyvinyl alcohol, and the other is the bacterium that produces the substances required by the active bacterium of PVA. The oxidation reaction enzyme of secondary alcohol catalyzes polyvinyl alcohol, and then the hydrolase cuts off the oxidized PVA main chain, further degrades, and finally degrades to CO2 and H2O

water soluble film has good packaging and environmental protection characteristics, so it has been widely valued by developed countries and has a very good application prospect. For example, Japan, the United States, France and other countries have produced and sold such products in large quantities, such as w.t.p company and c.c.i.p company in the United States, greensol company in France, which focuses on accelerating the transformation and upgrading of high-end high molecular composite materials, and Japan's synthetic chemical company. Its users are also some famous large companies, such as bayet (Bayer), Henkel (Henkel), shell (shell) Agr.eva and other large companies have begun to use water-soluble film to package their products. With the support of the science and Technology Department of China Packaging Corporation, Zhuzhou Institute of technology and Guangdong Zhaoqing Fangxing packaging materials Co., Ltd. jointly developed water-soluble films and production equipment, which have passed the provincial and ministerial appraisal. At present, they have been put into production, and their products are going to the market

research on other ecological plastic packaging

a. develop lightweight, film type, high-quality plastics. In order to reduce the total amount of plastic packaging waste in real-time display experiment time, all countries actively promote film and improve its quality. Japan has developed super tough and ultra-thin PET film with a thickness of 0.5 μ m, which is used for packaging precision electronic components. Finland has developed an opa/pe composite film, with a thickness reduction of 1/3, while other properties are not affected

b. develop recyclable and reusable plastics. If plastic packaging materials can be reused, the consumption of raw materials and environmental pollution can be greatly reduced. For example, the use of PET bottles, which are blown into new bottles after crushing, has little change in physical, chemical and comprehensive mechanical properties. Polyethylene naphthalate (pen) has better heat resistance than pet, can withstand the disinfection conditions required by low acid food, has better gas resistance and UV protection, can replace glass bottles, can be reused, and has a wide range of applications

c. develop new foamed plastics. Because the foamed plastic lunch boxes and cushioning packaging materials use less materials and use a large amount of materials, people study new foamed plastics. At present, dichloromethane foaming PS, PP and pet are ideal for the packaging of food and electronic products. The high-efficiency fluorine-free instapack polyurethane foaming agent developed in the United States can be foamed with few materials, can be repeatedly molded and used, and is easy to handle. The currently developed high melt strength polypropylene (HMSPP) and polypropylene homopolymer can produce foamed polypropylene, which can save 20% of raw materials compared with polypropylene sheets with the same performance, and the environmental load is also reduced

2. Natural biological packaging materials

using natural biological resources to develop packaging materials has the characteristics of low environmental load and rich resources. Making full use of bamboo, sawdust, hemp, cotton fabric, wicker, reed, crop straw, straw and wheat straw chitin and other raw materials, expanding packaging varieties and improving technical content has become one of the directions of packaging ecology

for example, straw board processed from straw has the functions of energy saving, heat preservation, heat insulation, sound insulation, good permeability, high impact strength, and significantly higher waterproof and seismic resistance than traditional materials; In addition, as a packaging material, the unit mass of straw board is 1/10 of that of paperboard with the same volume, which has obvious advantages; In China, we have developed a substitute of styrofoam lunch box with straw as raw material; Pu leaves can be made into disposable packaging after thermal characterization, bleaching and sterilization, which has attracted the attention of foreign importers

in addition to straw, other straw pulps are also used as the main raw materials in China to develop special cardboard for disposable tableware. It adopts the optimized application technology of chemical additives to improve the quality of straw pulp, ensuring that the straw pulp is close to the physical properties of wood pulp required for the manufacture of tableware paperboard, and the surface is suitable for food packaging