How much more expensive is biodegradable plastic than non-understandable ones

White Pollution

White pollution is the unique environmental pollution in our country's cities, a large number of discarded plastic products can be seen everywhere in a variety of public **** places, they come from nature, made by human beings, and ultimately attributed to nature but not easy to be consumed by nature, which affects the ecological environment of nature. From the perspective of resource conservation, plastic products should be recycled as much as possible since their main source is petroleum resources which are facing depletion, but it is difficult to do so under the current market economic conditions since the production cost of recycling is much higher than the direct production cost at this stage. In the face of the increasingly serious problem of white pollution, people want to find a substitute for the performance of existing plastics, but does not cause white pollution of plastic substitutes, degradable plastics came into being, this new function of the plastic, which is characterized by a certain life expectancy in the waste, in a specific environmental conditions, due to its chemical structure has undergone significant changes, resulting in the loss of certain properties and changes in the appearance of the degradation of the natural environment is harmless or less harmful. The natural environment is harmless or less harmful. For example, starch-filled plastics, first of all, the starch contained in a short period of time by the microbial secretion of amylase in the soil to rapidly decompose and generate voids, resulting in a decline in the mechanical properties of the film, and at the same time, the formula of the addition of self-oxidizing agent and the reaction of the metal salts in the soil to generate peroxides, so that the chain of polyethylene breaks down and degraded into a small fragment that is easy to be devoured by microorganisms to be consumed by the natural environment, and at the same time, play a role in improving the soil.

The earth is our home, and this home is being surrounded by garbage. As the masters of the 21st century, we can't just worry and complain, but we have to act and act green. Garbage is not useless, and waste products are not useless. Garbage resources and recycling is not technically difficult, the difficulty lies in the waste casually discarded, mixed and piled up to become garbage; therefore, as educated civilized people of the new century, we should participate in the "hand up" garbage source classification activities, in order to purify our living space to do a little dedication, dedication and a piece of love.

Living garbage is a by-product of human life. With the rapid development of social economy and the high concentration of urban population, the production of living garbage is gradually increasing. General household garbage can be divided into five categories such as waste paper, plastic, glass, metal and biological waste. The main hazards of garbage to human life and environment are:

First, occupying too much land. Piles of garbage in the outskirts of the city, encroaching on a large amount of farmland. Now the average annual production of garbage per person in Beijing is 440 kilograms, the city's annual production of about 4 million tons, equivalent to two and a half Jingshan. There are already more than 4,500 garbage dumping sites in Beijing, covering more than 10,000 mu of land. Garbage also stays in nature for a long time: cigarette butts and wool fabrics for 1-5 years; orange peels for 2 years; painted wooden boards for 13 years; nylon fabrics for 30-40 years; leather for 50 years; cans for 80-100 years; plastics for 100-200 years; Glass 1000 years. For this reason, we should not only create less garbage, but also pay attention to the classification of garbage, recycling and turning waste into treasure. Less disposable chopsticks, cups, lunch boxes and other products, more reusable products, reduce the consumption of valuable forest resources; less plastic bags, shopping bags, reduce the harm of urban "white pollution"; buy non-fluorine refrigerators, air conditioners and other environmentally friendly appliances, to protect the ozone layer of the atmosphere; less use of high-concentration detergents, the use of non-phosphorus laundry detergent, to reduce water pollution. The first is to reduce water pollution.

Secondly, it pollutes the air. Garbage is a complex mixture of ingredients. In the process of transportation and open storage, the decomposition of organic materials produce a bad smell, and to the atmosphere to release a large number of ammonia, sulfide and other pollutants, which contains organic volatile gases up to more than 100 kinds of these releases contain many carcinogenic, teratogenic substances. Plastic film, paper and dust are flying with the wind to form "white pollution".

Third, pollution of water bodies. Harmful ingredients in the garbage are easily washed into the ground water bodies by rain, in the garbage dumping or pit filling process will also produce a large number of acidic and alkaline organic pollutants, while the heavy metals in the garbage will be dissolved out. The exudate generated by the garbage pollution source will enter the underground water body through soil infiltration; the garbage is directly discarded into rivers, lakes or oceans, which will cause more serious pollution. You see: Summer Palace, Beihai floating on the water surface of the plastic bottles and lunch boxes, Fragrant Hills, Badaqi forested mountain paths scattered and hanging on the branches of plastic bags, bread paper, etc., some tourists only want their own convenience, resulting in environmental pollution of tourism. If the animals accidentally eat the white trash will not only hurt their health, and even lead to death.

Fourth, soil slagging. Garbage directly applied to agricultural land, or only after simple treatment for agricultural land will destroy the soil's granular structure, physical and chemical properties and water retention, fertilizer capacity. In particular, plastic bags, plastic sheeting, if buried in the farmland, the roots of crops can not grow, the farmland will be reduced, the food available for people to eat will be reduced.

Fifth, fire hazards. Garbage contains a large number of combustible materials, in the natural stacking process will produce methane and other combustible gases, in the case of open flame or spontaneous combustion easy to cause fire. With the increase in the organic content of municipal waste and scattered from the open piles into centralized storage, and in the long-term storage of only a simple cover resulting in garbage methane gas hazards are becoming increasingly prominent, garbage explosions continue to occur, resulting in significant losses.

Sixth, the nest of harmful organisms. Garbage not only contains pathogenic microorganisms, but also for rats, birds and mosquitoes and flies to provide food, habitat and breeding places, but also the root cause of infectious diseases.

In summary, the seriousness and urgency of the problem of urban garbage is obvious. To make these garbage into treasure, we need to do a good job of recycling and utilization of garbage. Do you know? Recycling 1 ton of waste paper can produce 800 kilograms of good paper, you can cut 17 trees, can save more than half of the paper energy, reduce water pollution by 35%; 1 ton of waste plastic can be at least 600 kilograms of gasoline and diesel back to the refining; with the waste glass to reclaim glass, not only can save quartz sand, soda ash and other raw materials, but also electricity; smelting metal with waste metal can save a lot of energy consumption, but also to reduce air pollution; and Some of the peel, eggshells, leaves, leftovers and other kitchen waste, can be processed by composting and fermentation methods, into green fertilizer and so on.

Therefore, we should vigorously carry out the publicity and education of garbage source classification and collection through various mass media such as TV, radio, newspaper and information network; urgently formulate the laws and regulations on garbage classification, collection and treatment suitable for the national conditions, and strictly enforce them; consider carrying out the pilot work of garbage source classification and collection in some units in depth; and further discuss with all of you to improve the management methods, so that the garbage source classification and collection can be carried out universally as soon as possible. source-segregated garbage collection as soon as possible to be carried out universally. Let's work together to promote the separation of garbage and recycling, remove garbage pollution, turn garbage into treasure, and conserve resources by raising our hands. So that Beijing can take a new look to win the 2008 Olympic Games hosting rights, but also to provide ourselves with a beautiful and healthy living space.

Plastic products as a lightweight, waterproof, corrosion-resistant new materials, in the world is widely used.

Plastic was first used in agricultural mulch, which brought great development to agricultural production, allowing crops to grow in any season and promoting market consumption. According to market statistics, since 1990 to 1995, the production of plastic to 8.9% annual growth rate, has swept the entire planet. It can be called the "white revolution". But it provides convenience for people at the same time, also brought a "white disaster".

To date, "white pollution" has become a well-known new term. It mainly refers to a variety of styrofoam bags, agricultural film, etc. to the environment caused by pollution, and get the general attention of the community.

Taiwan Province of China enacted a ban on "white products" in 1994, which was canceled a year later.

Hangzhou City issued a circular banning the local use of disposable styrofoam tableware as early as 1995.

Guangzhou City issued a government decree in June 1997 banning the production, sale and use of disposable non-biodegradable plastic lunch boxes in the city from September 1 of that year.

Based on this, in January 1999, the State Economic and Trade Commission issued Decree No. 6 of 1999, making it clear that disposable styrofoam tableware, as an outdated product, should be completely phased out by the end of 2000, and that from 2001 onwards, the production, sale and use of such products should be completely banned.

From the above material can be seen, today from the deadline has been more than a year past, but disposable foamed tableware is still everywhere, and the government also from the time of the mandatory "ban on white", the attitude of "ambiguous" up, often perfunctory, "ban on white". The "ban on white" has become a piece of paper.

In view of the above, we have conducted a multi-faceted research, access to a variety of information, and so far the country has developed and put on the market a variety of new substitutes for all aspects of the situation, and to analyze and summarize.

Difficult course

We went to the Xigu District Environmental Protection Bureau, in the Environmental Protection Bureau, we were warmly received, in the conversation we realized the "white pollution" the real composition, and a preliminary understanding of the "white pollution" hazardous concepts. We also got some understanding of the current program to combat "white pollution" (with a Q&A record).

We went to the Xinhua Bookstore, the provincial library, and the school library, but there is very little information about "white pollution", only polyethylene, polypropylene and polyvinyl chloride composition, the research process is blocked.

In order to get rid of the difficulties, we decided to use today's information technology - the Internet. On the Internet we found a vast space, so that we have a more profound understanding of "white pollution". And it helped us a lot in writing our thesis.

With the above foundation, we decided to further understand the "white pollution" in Lanzhou. We interviewed Hualian Supermarket, Power Supermarket, and some retail stores and vendors. We were y shocked by the fact that so many plastic belts and foam lunch boxes are thrown away every year, and people turn a blind eye to it. We feel that if we do not improve the quality of residents, to solve the problem of "white pollution" is too difficult. (With a survey form)

"White pollutants", with such a strong vitality, it will bring our lives what kind of serious harm, we will be described in the following content. First, let's understand the composition of plastic.

I, "white pollutants" components

"White pollution" mainly refers to white styrofoam lunch boxes, a variety of plastic bags, agricultural film and other environmental

pollution caused by the environment. But "white pollution" is not what people usually think of as plastic products. As we all know, plastic is a new material with excellent comprehensive performance, but also a consumer product, in general, it is also a substance. Any kind of material has its life cycle, and the whole process of reaching the end of its life cycle is the process of degradation, therefore, plastic itself is also degradable. It is only due to the stabilization technology, i.e., the addition of light and heat stabilizers, antioxidants, etc., that its inherent degradability is delayed or inhibited. Moreover, there are more than 300 kinds of plastics, more than 40 kinds of commonly used, and can actually become white pollution only accounted for a small part of them. Therefore, it is not possible to equate "white pollution" with plastics.

"White pollution" of the main components: polyethylene (PE), polyvinyl chloride (PV), polypropylene (PP),

Polystyrene resin (PS). Here we do one by one to understand:

Polyethylene:

Polyethylene is a thermoplastic resin produced by the addition polymerization reaction of ethylene. According to the different conditions of polymerization, the relative molecular weight of polyethylene can be obtained from ten thousand to several million. Polyethylene is a slightly white granule or powder, translucent, non-toxic, odorless, chemically stable, resistant to acid and alkali corrosion. Commercially, polyethylene is categorized into low, medium and high density. Generally used for packaging is mainly low density without plasticizers (0.92g/cm3-0.93 g/cm3)

Polypropylene:

Relative molecular weight of 80,000-200,000 between. Polypropylene main chain has a methyl side chain. If all the methyl groups are distributed on one side, it is called isotropic polypropylene; if the methyl groups are regularly distributed on both sides of the main chain, it is called intermediate polypropylene; if the methyl groups are irregularly distributed on the main chain, it is called atactic polypropylene. Polypropylene is usually a semi-transparent solid, odorless and non-toxic, density (0.90g/cm3-0.91g/cm3), mechanical strength is higher than that of polyethylene, good heat resistance. Three kinds of polypropylene, isometric polypropylene production is the largest. The use of titanium trichloride - chlorodiethylaluminum as a catalyst, in the hydrogenation of saturated gasoline to make propylene polymerization, isometric polypropylene.

Polyvinyl chloride:

Relative molecular mass of 50,000-12,000, polyvinyl chloride through the free radical addition polymerization reaction to generate polymer, is a thermoplastic resin. Amorphous white powder, no fixed melting point, density (1.35g/cm3-1.45g/cm3), with good chemical stability. Fused to acetophenone, chlorobenzene, dimethylformamide, toluene-acetone mixed solvent.

Polystyrene:

Average relative molecular mass of about 200,000. Colorless and odorless transparent resin, good light transmission. Glossy surface, flammable, density (1.05g/cm3-1.07g/cm3) has excellent water resistance, corrosion resistance, electrical insulation.

Production methods: body polymerization method, suspension polymerization method, emulsion polymerization method. Here we introduce the body polymerization method. Styrene monomer in the addition of initiators and a small number of additives, now in the pre-polymerization kettle for low-temperature polymerization, the preparation of pre-polymer, and then transferred to the polymerization tower of high-temperature heating, segmented to maintain a certain temperature, the end of the reaction is the molten polystyrene extruded into a strip, cooled and hardened in the water, cut granular packaging.

The above is the "white pollution" of the main ingredients, in addition, in these pollutants, but also added plasticizers

agent, foaming agents, heat stabilizers, antioxidants and so on.

Second, the main causes of white pollution is extremely harmful:

1. The main reason:

Plastic garbage is not properly managed and disposed of, the garbage is not classified and collected, can be recycled

not recycled, the final disposal of garbage basically stops at the level of bare piles or shallow burial, some towns will be rivers, rivers, lakes and coasts as natural The city's economy is in a state of flux.

Transportation, tourism, in addition to the railroad, has not been established with the production and operation of matching garbage collection Yong

The system, the production of garbage in the process of operation to let go.

Weak management? , the lack of relevant regulations on plastic packaging waste, as well as people's awareness of the environment is relatively weak; resulting in abuse and random dumping phenomenon is quite common, which is not the responsibility of the plastic products themselves.

2, the main hazards:

"White pollution" mainly refers to the environment caused by "visual pollution" and "potential harm" two negative

effects. p>Effects.

"Visual pollution" refers to the scattered in the city, people discarded plastic waste on the cityscape, landscape

destruction. For example, scattered on both sides of the railway, rivers and lakes in a large number of polystyrene foam plastic tableware and flying or hanging in the sky on the branches of the ultra-thin plastic bags, which bring people bad visual stimulation, the people reflect this strongly.

"Potential crisis" refers to the plastic waste into the natural environment and difficult to degrade the environmental problems brought about,

The hazards mainly include the following:

Not easy to recycle, because of recycling in the utilization of the high cost, but the utilization rate is low, the businessman can be said to be unprofitable

Can be profitable, and Because its recycling price is very low it is difficult to attract the general public to carry out "white recycling" work.

So, it is not easy to recycle.

Difficult to degrade. Recycling back to the white waste is not easy to deal with. At this stage, the main treatment methods are incineration

burning and landfill, if it is incinerated, it will produce a large number of toxic fumes, pollution of the atmosphere, and promote the formation of acid rain

and as for the landfill, it will be buried for 100 years, it is still in its original state, can not be naturally absorbed,

and the land has a great harm to the change of its pH, affecting the crops to absorb nutrients and water, resulting in agricultural

and the land is very dangerous, change its pH, affecting crops to absorb nutrients and water, resulting in agricultural

and the land is not easy to degrade. water, leading to agricultural

industry to reduce production, as for the abandonment of plastic products in the water or on land, not only affect the environment, but also if the passive

swallowed, it will lead to death. This disrupts the ecological balance.

High temperatures are decomposed toxic substances, plastic products are not toxic substances, but because of its recycling and reuse

use of equipment is not perfect, poor process, and many manufacturers do not have a legal business license, resulting in the reproduction of

plastic products at a temperature of 65 ℃, toxic substances will be precipitated and infiltrated into the food, it will be the liver

deliveries, kidneys, reproductive system and central nervous system and other important parts of the human body to cause harm.

Three, "white pollution" has a broad market for the reasons and in the management of the process of the relevant problems

In the previous, we have mentioned the Economic and Trade Commission's document, the document clearly pointed out that: "by the end of 2000 to completely

end of the elimination of all foaming Plastics". But today, styrofoam still exists, why it has such a strong vitality! The reason for this is the following:

The finished product of biodegradable materials is not mature. Because of the complexity of its production process, its price is higher than the "white

products" 1 to 2 times, people are certainly not willing to "chaff to take expensive". On the other hand, biodegradable materials

manufactured products are not as good as "white products", because the production process of "white products" after many years of experience

summary, is now mature, while the new materials have just been developed, and some require a lot of wood. Some also need a lot of wood, although

products degradation, but the ecology, water pollution and damage.

The crackdown is not strong enough. Now the restaurant, restaurant sales of "white products", the use of quite

prevalent, open, blatant market transactions, turning a blind eye to the state regulations, so that the years of "ban

white" work into a "white ban".

National quality needs to be improved, the quality of a citizen reflects the national quality of a country, but

To date, people's awareness of environmental protection is still very weak, throwing discarded items habit is still very common, this phenomenon will give us a great harm to the natural environment, and the emergence of this phenomenon, to the "white discarded articles The phenomenon will bring great harm to our natural environment, and the emergence of this phenomenon will bring great problems to the "white waste products" recycling.

For "white pollution" recycling facilities are not complete. As mentioned earlier, the utilization rate of "white

pollution" recycling is low, mainly due to the backwardness of China's technology and insufficient capital investment, so some of the new products researched in China can not be put into production and use.

Manufacturers from the "public" to "semi-public", with the introduction of the national "white" policy, "white

Products

By the above examples, we can see that nowadays there are two main ways to solve the "white pollution": waste plastic resource utilization and biodegradable plastics.

A: waste plastic resource utilization (that is, the recovery of waste plastic, as a resource, to be developed and utilized.)

(1) directly as a material, some renewable plastic products, can be recycled, processed, and then made into new plastic products.

(2) make synthetic polymer units. Polymers are polymerized from monomers, then under certain conditions can be made from waste plastics into monomers. Such as polyester plastics made of monomers by alcoholysis.

(3) make fuel oil. Polymer chains will be cracked at high temperatures. Such as polyethylene, polypropylene at high temperatures can be decomposed into low molecular petroleum hydrocarbons, and then fractionated to get a variety of fuel oil.

B: Biodegradable plastics ．

(1) natural polymer transformation method. Is to starch, cellulose, chitin, lignin, seaweed and other natural macromolecules as raw materials, through chemical modification and **** polymerization methods, these molecules are transformed to synthesize plastics that are easily biodegradable.

(2) Chemical synthesis method. Simulation of natural polymer structure, starting from a simple water molecule, in the plastic polymer chain with active groups such as amide, peptide, ester group, containing these groups of compounds similar to natural proteins, fats and oils of the structural fragments, easy to be biodegradable.

(3) microbial fermentation, many microorganisms can be certain organic matter as a carbon source, through metabolism, secretion of polyesters, polysaccharides polymers, these molecules are easy to degrade, but also can be further recycled.

But, due to the different structure of plastics and contains some special additives, some plastics are not suitable for recycling; there are also some plastics by the processing of the initial explanation of the fragments, and then degradation in the natural environment is very slow, can not completely solve the "potential harm" to the environment. Therefore, on the one hand, in the "white pollution" control at the same time, on the other hand, should actively prevent the emergence of new sources of "white pollution". To this end, China's environmental protection department, the prevention and control of white pollution should be implemented "to publicize and educate as the leading, to strengthen the management of the core, recycling as the main means to product substitution as a supplement to the principle of".

Of course, "white pollution" is a world problem, due to its limited development, we can not be in-depth study. What we can do today is limited to collecting and organizing information. But by studying this issue, we can also understand "white pollution" in general.

While we have understood the treatment and solution of "white pollution" in the world today, we have not been able to make a complete solution. In the process of research, we y feel that the low quality of people's environmental damage is serious, only to improve people's awareness of environmental protection, is the most feasible way to solve the "white pollution".