In the world, polymer products are the youngest materials. They are not only used in various industrial fields, but also have entered all families, and their output tends to exceed that of metal materials, and will be the most active material pillar in 2 1 century.
Polymer materials are organic compounds, and organic compounds are compounds of carbon. In addition to carbon atoms, other elements are mainly hydrogen, oxygen, nitrogen and so on. Stable structures can be formed between carbon atoms and between carbon atoms and atoms of other elements. Carbon atoms are tetravalent, and each monovalent bond can bond with a hydrogen atom, so countless organic compounds with different structures can be formed. The total number of organic compounds is close to 10 million. Far more than the sum of other elemental compounds, and new organic compounds are constantly being synthesized. Thus, due to the formation of different special structures, organic compounds have unique functions. Some organic structures (also called functional groups) can be substituted in the polymer to change the characteristics of the polymer. The molecular weight of polymers is huge, reaching at least 654.38+100000, or millions to millions, so people call them polymers, macromolecules or polymers. Polymer materials include three kinds of synthetic materials, namely plastic, synthetic fiber and synthetic rubber (called resin before processing).
The rapid development of high technology in 2 1 century has promoted the leap of social economy and other industries. Obviously, polymers have assumed the historical responsibility and are developing in three directions: high performance, multifunction and biochemistry. 2 1 century materials will be a brilliant polymer kingdom.
The existing polymer materials have high strength and toughness, which can be compared with metal materials. Most of the metal structures of our daily household appliances, furniture, washing machines, refrigerators, televisions, vehicles, houses, etc. Has been replaced by polymer materials. The development of industry, agriculture, transportation and high technology requires polymer materials to have higher strength, hardness, toughness, temperature resistance, wear resistance, oil resistance and folding resistance.
In improving the properties of polymers, the most important thing is to make composite materials. The first generation composite material is glass fiber reinforced plastic, which is made of glass fiber and synthetic resin as binders. It has excellent properties such as light weight, high strength, high temperature resistance, corrosion resistance, low thermal conductivity and easy processing, and is used in rockets, missiles, ships, automobile bodies, TV antennas and so on. Later, people used carbon fiber instead of glass fiber, and carbon fiber was lighter. Its strength is 3~5 times higher than that of steel, so it is the second generation composite material. If aramid fiber is used instead, its strength is five times higher than that of steel wire. There is still great potential for the development and innovation of high performance polymer materials. Scientists predict that between 265,438+05,000 and 20 million tons of fiber materials must be produced every year to meet the demand. Therefore, it is necessary to produce a large number of synthetic fiber materials, which are more lightweight, fire-resistant, flame-retardant, odor-resistant, water-absorbing and bactericidal. Many new fibers, such as light cavity fibers, foam fibers, fibers with various cross-sectional shapes and multicomponent fiber materials, have been developed one after another. People can expect that fiber materials with antistatic, dirt-resistant, oil-resistant and even pollution-free properties will come out. These fiber materials will be used for aerial antennas and aerial reflectors.
Polymer functional materials are a magnificent landscape in the polymer kingdom. Because the functional groups of polymers can be replaced, various polymer functional materials can be manufactured by extremely simple methods. Commonly used water-absorbing materials, such as cotton and sponge, weigh only 20 times, and most of the absorbed water will be squeezed out during extrusion. The polymer water-absorbing material made of starch and acrylonitrile can not only absorb hundreds to thousands of times its own weight, but also won't squeeze out water when it is squeezed. People can expect to make super absorbent polymer materials into devices that can convert chemical energy into mechanical energy, which have muscle-like functions or make measuring instruments. In the lithography integrated block process of microelectronics industry, the commonly used photoresist (also known as photoresist material) is to connect polymers with a functional group. When light is irradiated, a chemical reaction will occur, reducing or improving its solubility. When using this photoresist to prepare the integrated block, the line width of the integrated block can reach 0. 1 to 0.0 1 micron (1 mm), which is only 11to1. Suitable for switches of main components of electronic computers in 2 1 century. The photoresist can also be used for various fine machining, such as the fine machining of semiconductor components, EP printed circuit boards, metal films or surfaces, the fine etching of glass and ceramics, and the machining of precision mechanical parts.
Polymer functional materials have been used in information engineering, resulting in photoconductive materials, optical information recording materials and optical mm energy conversion materials, all of which have entered the practical stage.
The ion exchange resin polymer functional materials similar to the "contemporary Moses scared tree" have also developed rapidly. Many polymer ion exchange membranes, polymer reverse osmosis membranes, polymer gas separation membranes, polymer vapor permeation membranes, etc. It has been used in chemical screening, precipitation, filtration, distillation, crystallization, extraction and adsorption, and the separation effect is better than other methods. It can save a lot of energy. The salt-making industry in Japan has used ion exchange membrane instead of salt pan and electrolytic salt-making process. Using reverse osmosis membrane to treat the "three wastes" in organic chemical industry and liquor-making industry, important organic compounds such as amines, esters, alcohols, ethers, ketones and phenols can be recovered. Gas separation membrane has different permeability and selectivity for different gases, so it can be used to selectively separate a certain gas from mixed gases, such as enriching oxygen from air and recovering hydrogen from synthetic ammonia. Collecting helium from natural gas can also be used to prepare an underwater respirator (artificial gill), which is a diving device that directly extracts oxygen from seawater. Humans are expected to live in seawater for a long time and enter the palace of the sea dragon king. The dream of sharing the quiet and happy life of the sea dragon king can come true. There are various information conversion membranes, reaction control membranes and energy transfer membranes. It is under development. An attractive biofilm is also being studied. Biofilm has unique properties, which can not only actively transmit energy, information and substances, but also participate in life activities such as photosynthesis and organic matter biosynthesis. This is a high-tech pearl of 2 1 century. We can pick this pearl.
Another extremely important development of polymer functional materials is to promote chemical reactions. This polymer functional material is called polymer catalyst. As early as 1940s, people used an ion exchange resin called crosslinked sulfonated polystyrene as a catalyst for various chemical reaction processes, such as hydrolysis, condensation and polymerization. Later, this kind of polymer functional materials developed rapidly and polymer metal complex catalysts came out. It can accelerate the capture of metal ions in chemical reactions and realize the rapid separation of metal compounds, which is a very important method in industrial production and industrial analysis. There is also polymer metal catalyst, which is a material to promote the rapid completion of chemical reactions of metal ions in compounds and has been successfully applied. There is one of the most effective catalysts in nature, called enzymes. This polymer material has a strong catalytic effect like an enzyme. It is called synthetase. Enzymes are protein polymers composed of amino acids. It is an efficient catalyst for various biochemical reactions in organisms and a natural polymer functional material with the best performance. Now, various synthetic enzymes have been successfully developed and gradually put into use, and there are more and more kinds. Scientists try to imitate the catalysts used in the chemical industry according to the action principle of enzymes. Carry out a revolution in the chemical industry. It can carry out chemical production, make full use of renewable biological resources, get rid of the traditional synthesis process with petroleum series as the main raw material, and also use the catalytic principle of enzyme to avoid the high temperature and high pressure conditions in the traditional synthesis process, and selectively make specific substances react in the mixed state of various substances. The reactants can continue to react without separation until the final product is produced. In this way, the bioreactor will change the traditional appearance of high-rise buildings in chemical enterprises, not only save energy and improve the working environment, but also open up chemical resources and eliminate waste water, waste gas and waste materials, making it possible to establish an ideal chemical industry without pollution. For example, the neutral resin made of asparaginase has a bright future.
Polymer materials have been used in medicine and life sciences for a long time, but with the progress of high technology, the development in this field in recent years is surprising. Artificial heart valves, artificial lungs, artificial kidneys, artificial blood vessels, artificial skin, artificial bones and artificial joints have been rapidly developed and improved, and have been put into use. There are countless surgical instruments and medical supplies made of polymer materials.
The biggest feature of biopolymer materials is to control human health and life. The use of non-pharmaceutical polymers synthesized with other drugs can greatly improve the therapeutic effect. This medicine is easily absorbed by human body and has little toxic and side effects. For example, anti-cancer drugs that cause adverse reactions such as nausea and general malaise will be polymerized, and the effect will be greatly improved. For example, anticancer drugs, aromatic heptanone and methacrylic acid are combined into polymers. The effect is better. Another polymer drug, such as synthetic polyvinylpyrrolidone, can be used as a substitute for plasma. Polymer drugs synthesized from commercial polyether and polyurethane have a particularly high affinity with albumin in plasma proteins and get along well with each other, which is a medical polymer material to solve human coagulation.
To sum up, polymers have become a powerful pillar of materials science in 2 1 century, and the development of polymer materials will make greater achievements in 2 1 century.