Functional polymer materials

Functional polymer materials Zhang Guangyan, Wang Xuhong, Ning Zhiqiang (Heilongjiang Institute of Petroleum Chemistry, Harbin 150040, Heilongjiang) Electropolymers were discussed separately.

Foreword Since the 1970s, the development of polymer science has become more mature. Its main development directions are: First, continue to make large-scale industrialization of general-purpose polymers, high-efficiency catalysis strive to reduce costs, improve performance, and expand usage; second, develop composite materials and high Performance engineering plastics are used to replace various metals as vehicles: lightweight, high-strength structural materials for aircrafts, aircrafts, vehicles, boats, etc. The most representative are composite materials, bonded honeycomb structures, engineering plastics, etc. , can reduce the quality of transportation Tools by about 20%, which is very important for energy conservation and speed increase, and improve the benefits; third is functional polymer materials, which refers to the original mechanical properties of synthetic or natural polymers based on New polymers such as catalytic, conductive, photosensitivity, chemical, selective separation and other special functions are given. This does not include conventional polymers such as heat resistance, high strength, and insulation, but they are classified under the category of general-purpose polymer modification. The so-called functional polymer is a type of novel polymer having reactive functional groups in the main chain and side chains of the polymer and having reversible or irreversible physical functions or chemical activities.

The main way to synthesize functional polymers: one is the polycondensation or polyaddition of monomers and polymers with functional groups; the second is to connect functional groups to polymer chains through chemical reactions, such as loading Two or more functional groups can exhibit multiple functions.

At the same time, the polymer chain can be given hydrophilicity and hydrophobicity, so that it has a different reaction environment; adsorption and desorption are easier; the macromolecule itself deforms freely, and reversible morphological changes can occur. A wide range of functional polymer materials are used for a wide range of applications. For example, porous membranes used in separation projects can separate gases, liquids, and solids; polymer enzyme catalysts in reaction engineering; photosensitivity, electrosensitivity, and thermal sensitive materials used in electronic information; and medical engineering. In the artificial organs, drug release agent materials and so on. Functional polymer materials increase the added value of inexpensive general-purpose polymer materials by technology, and have won new markets. It is a small but sophisticated product with high cost but special advantages. The development of functional polymers is in the ascendant, and is forming a new field with a unique performance and a wide range of uses, and it has received widespread attention from all countries in the world. It is expected that in the future chemical product market, it will occupy an extremely important position, and it is standing in the polymer product market with the development of the general polymer, lightweight high-strength composite materials.

1 The main functional polymer materials The functional polymers involved in a wide range of subjects, rich in content, according to its main functions can be divided into the following categories: ion exchange resin, polymer separation membrane, medical polymer, polymer catalyst, high conductivity Molecules, light-sensitive polymers, etc., are briefly described as follows: 1.1 Ion-Exchange Resins The ion exchange resins are three-dimensional network cross-linked polymers with ionizable groups. The commonly used ion exchange resins are mostly spherical beads having a particle size of 0.3 to 1.2. The particle size may vary depending on the particular application. In addition, it must have high mechanical properties, good chemical stability, thermal stability, hydrophilicity, osmotic stability, and high exchange capacity. It has large enough gel pores or macroporous structure in water. Due to its high efficiency and rapid analysis and separation capability, it has been widely used in hard water softening, wastewater purification, high purity water preparation, seawater desalination, solution concentration and purification, and uranium extraction from seawater. Especially in the food industry, the pharmaceutical industry, pollution control and catalysts are more widely used, and they are developing rapidly. In addition to the commonly used ion exchange resins, ion exchange resins having special selective functions have recently been developed: chelating resins, redox resins, adsorption resins, etc. These polymeric adsorbents can be used in polar or non-polar solutions. Adsorption of polar or non-polar solutes, their ability to adsorb impurities in water is extremely strong, up to ppb (parts per billion), and this adsorbent has recently been used to remove toxic substances in the blood.

1.2 Polymer Separation Membrane Macromolecular separation membrane is a functional polymer with separation function. Membrane separation technology utilizes the selectivity and permeation performance of the membrane to the components of the mixture to separate the mixture. Generally, no phase change occurs, and no phase change energy is consumed. This is a separation technology with low energy consumption and high efficiency.

It is sometimes necessary to raise the temperature a bit in order to increase the mass transfer rate. It is very similar to the filtration process, the driving force has pressure difference, concentration difference, partial pressure difference and potential difference. It is of great significance for the reuse of water resources, the preparation of pure water, and the direct protection of the environment from the recovery of corresponding resources from waste water and waste gas. It is also widely used in the chemical industry, food industry, pharmaceutical industry, and biological engineering. From the actual use of polymer membrane separation process can be divided into dialysis membrane separation; filtration membrane separation (including ultrafiltration, microfiltration, reverse osmosis and gas infiltration, etc.); liquid membrane separation similar to extraction and back extraction, solute from The liquid film enters the liquid film equivalent to the extraction, and the solute enters the liquid film again. The receiving liquid is equivalent to back extraction.

Since the second half of the 20th century, polymer separation membranes have been growing at an average annual rate of 10% to 20%. According to the European Chemical News (1982), the output value of gas separation membranes is 50 times longer from 1982 to 1990, and has formed a An important new-type industry with an annual output value of over 10 billion U.S. dollars.

1.3 Medical Polymer Materials Medical polymer materials are used in the medical field of artificial organs, treatment of diseases, and diagnostic tests. Because of its relevance to the life sciences, they have received increasing attention from people. It is an edge discipline where biology, medicine, chemistry, and materials science intersect. Medical polymer materials must have the advantages of high purity, chemical inertness, stability, and resistance to biological aging.

It is biodegradable, and the degradation products are not toxic to the body and can be easily discharged. For materials that are permanently implanted in the body, they must be able to withstand long-term biological aging effects, such as being able to withstand the effects of blood, body fluids, and various enzymes, and must also be non-toxic. , No carcinogenic, no inflammation, no rejection, no coagulation; also have the corresponding biomechanical properties, good processability and a certain degree of heat resistance, easy to disinfect and so on. People commonly used medical polymer materials are: organic polymer, organic glass, nylon, polyester, PTFE and so on. Before 1960, people had selected suitable materials for use in ready-made high-molecular materials and used them according to requirements. However, it was found in practice that problems such as coagulation and inflammatory reactions were difficult to solve, and people realized that they must It is necessary to design medical polymer materials in order to be safe and reliable, based on the objective needs of medical applications, especially biocompatibility. In recent years, the United States, Europe and Japan have made rapid progress in the research and development of biomedical polymer materials. From artificial organs to high-efficiency sustained-release polymer drugs, they have achieved a lot of results and tremendous benefits. According to the report of the American Health Industry Manufacturers Association, the world market reached 120 billion U.S. dollars in 1995, and the U.S. was 51 billion U.S. dollars. It is expected that it will become the pillar industry of the national economy in the 21st century.

1.4 Macromolecules Drug macromolecules are new drugs that were developed in the 1950s. One of them is based on polymers themselves as novel drugs. Some soluble polymers can be directly used as drugs, such as natural polymer enzymes, anticoagulant natural heparin, and various mimetic enzyme drugs. Synthetic polyvinylpyrrolidone can be used as blood volume expander, anti-cancer drug divinyl ether and maleic anhydride alternate copolymer, etc., but there are few varieties at present and need to be further developed. The second is the main class, in which macromolecules are used as a drug carrier, and a low-molecular-weight compound with pharmacological activity is attached to the carrier in the form of an ionic bond or a covalent bond, and a controlled release preparation of a macromolecular drug is prepared. Two: One is to make the drug produce a therapeutic effect at a specific site with the smallest dose, and the second is to optimize the drug release rate to increase the curative effect, reduce the toxic and side effects, and achieve: (1) Long-acting effect: commonly used low-molecular drugs are relatively The molecular weight is small, the residence time in the blood is short, and it is easy to excrete, so the efficacy is short. Penicillin G and penicillin V do not have long-lasting effects. If they are linked to the polyvinyl alcohol and vinyl amine copolymer molecular chains, the drug effect can be prolonged by nearly 40 times.

(2) Effect: Not all drugs can increase the drug efficacy after macromolecularization, but as long as the carrier is selected, the appropriate carrier can direct the drug to directly attack target cells of the diseased cells or change the drug transport in the target tissue. And distribution, or add osmosis, lead to efficiency.

(3) Sustained release effect: After the drug is microencapsulated, it can enter the designated disease (turning down to page 322). For non-permanently implanted materials, it is required that the phenol-containing waste water produced in industrial production can be printed and dyed within a certain period of time. When colored wastewater is used, the effect is better. Chlorine dioxide sterilizes and deodorizes the domestic wastewater in the hospital ward environment, and can be effectively purified with better performance than chlorine.

(3) Preservation and preservation of foods and beverages: Soaking of meat, aquatic products, poultry, etc. with chlorine dioxide solution can inhibit microbial growth. Adding chlorine dioxide as a preservative to beverages can extend shelf life. (4) Medical treatment: Chlorine dioxide is used for dental disinfection, which can inhibit the propagation of pathogens to effectively control bad breath, plaque, and gingivitis. Glass, plastic, ceramics and other medical and experimental products can be sterilized by soaking in chlorine dioxide solution. (5) Chlorine dioxide is one of the components of air fresheners and lotions used to remove offensive odors.

4 Conclusions (1) Humic substances and algae, which are precursors of disinfection and metabolism, have been studied in great quantities. However, the non-humus components in natural water bodies have been considered to have no effect on the quality of effluent and have been neglected. However, studies have found that disinfection in recent years has resulted in disinfection. A significant portion of the by-product precursor material comes from the non-humus portion of the water. Calculated by dissolved organic carbon (DOC), similar to the disinfection by-products formed by humus, they may be composed of hydrophilic acids, proteins, amino acids, carbohydrates, etc., have strong hydrophilicity and low aromaticity, and are Biodegradable parts, its toxicity needs further study.

(2) As a disinfectant, chlorine dioxide has the characteristics of small dosage and good disinfection and sterilization effect. Although it does not produce HAAs and other halogenated carcinogens, it also has a problem of by-products as a strong oxidant involved in the oxidation reaction. During use, consideration should be given to minimizing the production of by-products and the removal of by-products.

(3) Any kind of water treatment process has its limitations. The organic combination of multiple physical, chemical, and biological technologies (such as ozone-biological pretreatment-membrane) is the focus of future research and will be based on their respective advantages. Synergy to achieve the best water purification effect.