1:A polymer medium is a special medium, its speciality is that there are different groups in the macromolecular chains and chains in which there are different structures, and their movement forms also have their particularity, and thus in the polymer medium There will be different forms of energy conversion. This special function of polymers has been increasingly used in various fields of military, aerospace and national economy.

1 Mechanical Energy Thermal Energy Viscoelastic polymers have a high internal friction near their glass transition temperature range. They can convert mechanical vibration energy into heat energy and dissipate. This characteristic of viscoelastic polymers allows them to be used as damping materials in subtraction. Vibration and noise reduction has been widely used. One of the main properties of polymer damping materials developed in the 1950s was the wide damping temperature range and high damping factor. The damping temperature range of single-phase polymers is very narrow, and therefore the wide-temperature damping materials are usually multiphase systems. By controlling the compatibility between the high polymer phases, the semi-compatible state of the high polymer phases can effectively broaden the damping temperature range. There are two main methods for controlling the interphase compatibility of polymers. One is to change the macromolecular structure of the polymer. Taking a polyoxypropylene glycol-MDI-f chain polyurethane system as an example, by changing the degree of cross-linking of the polyurethane, an irregular chain extender with side groups is selected to lower the crystallinity of the hard segment, thereby making the soft-hard segment macromolecular chain strong. The interaction, the introduction of fat rings in hard segments, and the introduction of different soft segments of graft chains in the backbone can greatly expand the damping temperature range of polyurethanes. The addition of appropriate flaky fillers plays a role in constraining the movement of macromolecular chains, and can also significantly improve the damping properties of damping materials. The introduction of ionic bonds on macromolecular chains not only greatly expands the damping temperature domain, but also significantly increases the damping factor. The second is the use of polymer blending technology. The products of mechanical blending generally have large domains and are generally not suitable for damping materials. The interpenetrating polymer network (IPN) technology can effectively control the compatibility of the polymer blend components through network interpenetrating and chain twisting effects, and broaden the damping temperature region. S-top technology, Semi4PN technology, Latex~IPN technology, and bi-directional interpenetrating Latex-PN technology have all been used to prepare high-performance damping materials. The rearrangement of macromolecular chains, conformational changes, the formation and dissociation of hydrogen bonds, and the introduction of ionic bonds all contribute to the conversion of mechanical energy into heat energy. For compatibility characterization, factor analysis and nuclear magnetic resonance techniques have been applied. At present, polymer damping materials have been widely used in industrial, traffic, military and other fields.

Another field of application where mechanical energy is converted into thermal energy in a polymer is a cavitation erosion material. Cavitation occurs on the surface of a metal that is exposed to high velocity fluids. Here, a large number of voids are generated in the fluid, and the instantaneous collapse of the vacuole can generate a high temperature of about 5000 K, a high pressure of 108 Pa and a micro jet flow at a speed of 400 km per hour, resulting in roughening and destruction of the surface of the material and loss of use performance. Cavitation erosion is often referred to as cavitation erosion. Cavitation erosion is unavoidable in certain situations, such as in the vicinity of propellers of high-speed boats and the blades of hydro-generators and their vicinity. An effective method for suppressing cavitating corrosion Wen Qingzhen et al.: The energy conversion in polymer media is the use of a high-performance organic coating that absorbs the impact energy of shock waves or micro-jets to protect the metal. An anti-cavitation coating based on flexible polyurethane and epoxy resin has good performance in converting impact energy and has been applied on ships.

2 sound energy to heat energy When the acoustic wave acts on the polymer medium, the energy will be transmitted to the macromolecular chain segment, causing macromolecular chain thermal motion. Generally, high-damping polymers are suitable for underwater sound absorbing materials such as butyl rubber and urethane rubber. Sound-absorbing polymers have been widely used in underwater acoustics and military applications. In the latter part of World War II, Germany laid a layer of rubber on the submarine to absorb sonar waves and reduce the active distance of the enemy's active sonar. In the early 1960s, in the former Soviet Union, the United Kingdom began to study the use of wrapped sound-absorbing materials on the surface of submarines to prevent the detection of active sonar. In addition to being used in the military field, sound-absorbing materials also have broad application prospects in construction, transportation, and environmental protection. Polymeric rock wool foaming materials and foamed polymer/inorganic composite materials all have sound absorption and decorative properties. , environmental protection and other features.

3 Radiant Thermal Energy From the viewpoint of energy conversion, a microwave absorbing material is a transducer material that converts radiant energy into thermal energy. There are two types of radar absorbing materials: inorganic conductor/polymer composites and conductive polymer materials, both of which can be coated and structured. Among them, inorganic conductors/polymer composites are an important research direction for stealth materials, and they have been widely reported at home and abroad. The American F-117 and B-2 fighter jets and advanced missiles have all adopted carbon fiber and carbon/kavlar fiber composite polymer wave-absorbing materials in large quantities, which greatly reduces the radar wave reflection cross section and plays a very good role in stealth. These stealth The aircraft can both break the defense from high altitudes and from low altitudes, verifying its excellent stealth and combat capabilities in the Gulf War and the Yugoslav bombing. The U.S. regrettably shadowed "ship" stealth ship uses a ferrite/polymer composite absorber that has a very good stealth effect.

The rapid development of anti-stealth technology puts forward higher requirements on wave absorbing materials, so that new types of wave absorbing materials continue to emerge, and conductive polymers as new types of wave absorbing materials are highly valued by countries in the world.

It has become a new hot spot in the field of conductive polymers, and it is a breakthrough to realize the practical application of conductive polymers. The measurement results of the electromagnetic properties of conductive polymers in the frequency range of 1 GHz to 18 GHz indicate that the conductive polymers are conductive. The dielectric loss is much greater than the magnetic loss, so the conductive polymer is an electric loss type radar absorbing material. Under the action of electromagnetic waves, both the oriented polarization and the interfacial polarization of the intrinsic dipole of the conductive polymer will result in dielectric loss to convert the electrical energy into thermal energy. Conductive polymer radar absorbing materials have difficulty in thinning the coating thickness and extending the absorption band. For this reason, improving the magnetic loss of conductive polymers is the key to the practical application of conductive polymer radar absorbing materials. At present, such materials have not entered the practical stage as stealth absorbing materials. However, methods for preparing conductive polymer microtubules and nanotubes, such as cheek plate synthesis, molecular deposition method and scanning microprobe electrochemical method, have emerged one after another, as well as the morphology of the conductive polymer, and the spiral chirality. The intelligentization and intelligentization have provided new means for the development of conductive polymer absorbing materials. In particular, the method for synthesizing buccal plates has successfully produced polyacetylene, polypyrrole, and polyaniline microtubes, and has discovered micropipes that have been developed. It has excellent electromagnetic loss in the frequency range of 1GHz18GHz, which opens up a new way for the preparation of conductive polymer absorbing materials.

4 electrical energy into heat conductive polymers used in addition to conductive materials, electroluminescent materials, anti-static materials, electromagnetic shielding materials, absorbing materials, but also can be used as thermoelectric materials, to achieve electricity / thermal energy conversion. The thermoelectric properties of thermoelectric materials are generally described by the thermoelectric sensitivity value Z=S2D/K. The larger the thermoelectric coefficient (S) of the material, the greater the electrical conductivity (D) and the smaller the thermal conductivity (K), the higher the thermoelectric conversion efficiency. . With the advent of new doping methods and synthesis methods, the electrical conductivity of conductive polymers has been greatly improved. It is estimated that the thermoelectric properties of conductive polyaniline and polypyrrole reach ZT>1 (T is the average temperature of the material), and currently due to the polymerization There are relatively few researches on thermoelectric materials, and there is still a large distance between these materials and practical applications.

5 electrical energy radiation energy phenyl acetylene is not only a good conductive polymer material, its eigenstate PPV is also a good electroluminescent material, made of a single layer of electroluminescent devices can be issued at 14V international The study of conductive polymer radar absorbing materials not only produces yellow-green light. This discovery opens up a new field of conjugated polymers for the study of polymer materials science and engineering.

Electroluminescent materials are transducer materials that convert electrical energy into radiant energy. Because the excitation of electrons in the polymer material is non-linear, the injection of electrons and holes on the conjugated chain can form self-localized excited states, which can effectively cause radiation decay and cause light emission. At present, there are three types of polymer electroluminescent materials: polyarylacetylene, polyarylene, and suspension. Among them, polyphenylene vinylene (PPV) and its derivatives are the most studied so far, and they can emit light with a wavelength of 480 nm and 710 nm. It is found that the proportion of alkyl groups is large, and the emission wavelength is blue shifted, and the proportion of alkoxy groups is added. , The emission wavelength is red-shifted. The introduction of alkoxy groups results in a red shift of the emission wavelength. When the conjugated moiety is introduced into the PPV, the emission wavelength shifts blue. For polyarylene systems and suspension systems are also more active research, such as poly 1,4-phenylene compounds, polythiophene electroluminescent materials, poly (9,9-dihexyl fluorene) electroluminescent materials.

As a novel information display material, electroluminescent material has the advantages of easy processing, high luminance and efficiency, adjustable light emission wavelength in the synthesis process, low driving voltage of the manufactured light-emitting device, and a wide application prospect. However, these types of polymer materials still have problems such as insufficient stability and need to be further solved.

6 Mechanical energy, sound energy change Electrical energy In addition to inorganic piezoelectric materials, such as piezoelectric ceramics (lead zirconate), piezoelectric crystals (quartz crystals) can convert mechanical and acoustic energy into electrical energy, polymers and composite materials such as Polyvinylidene difluoride (PVDF), vinylidene fluoride/trifluoroethylene copolymers and their composite materials also have strong piezoelectric properties, which can realize the conversion between mechanical energy or acoustic energy and electric energy.

The use of polymers as energy conversion materials has caused great interest. Compared with inorganic piezoelectric materials, polymer piezoelectric materials have unusual features: First, piezoelectric polymers have high piezoelectric constants, high receiving sensitivity when used as a receiving material, and because of their mechanical properties. Internal friction is large, but there is almost no lateral coupling, so the receiving frequency band is very wide, suitable for sensitive broadband receiving transducing material; Second, piezoelectric polymer is soft, resistant to mechanical impact, easy to match acoustic impedance, can be made of very large area Large and thin components can overcome the effects of flow noise when used as a sonar in a ship. The new-generation white captain of the United States has used piezo rubber as the material for the sonar array of the submarine of the level attack submarine, and Norway and France have also tried PVDF as the underwater acoustic transducing material on their ships. With PVDF, the weight is light and the distortion is small. The sound quality is good and the stability is high, and it has been widely used in acoustic equipments, medical instruments, etc. Piezoelectric polymer materials have limited use temperature due to unsatisfactory thermal stability.The recent research on aromatic polyurea films is piezoelectric high. The molecular material overcomes this limitation and brings hope.The polyurea polymer compound has a strong aromatic ring molecular skeleton and a strong hydrogen bond between the -NHCONH-groups, making it a high pressure resistant, comprehensive performance. Electrical materials.

With the continuous deepening of research on piezoelectric polymers, excellent piezoelectric polymer materials have been successfully developed. In particular, piezoelectric composites composed of piezoelectric ceramics and piezoelectric polymers overcome the brittleness of piezoelectric ceramics and the temperature limit of piezoelectric polymers, and retain their advantages, becoming a research hotspot for piezoelectric materials. Piezoelectric ceramics/polymer composites are composed of piezoelectric ceramics and piezoelectric polymers in a certain degree of connectivity, a certain volume (or mass) ratio, and a certain geometric space distribution. After compounding, they can greatly improve the composite. Piezoelectric properties of the material: According to the connection of the two materials, ten types and two numbers respectively represent the connected dimensions of the piezoelectric ceramic and the polymer.

The 1-3 and 2-2 composite piezoelectric materials developed in China have been used for non-destructive testing of P-wave and S-wave transducers for water immersion flaw detection and lithology detection. In addition, the hydrostatic pressure sensitivity of 3-3 connected piezoelectric composites developed in China is particularly high, which is several orders of magnitude higher than pure PZT piezoelectric ceramics.

7 Mechanical energy change Mechanical energy can hardly be converted into chemical energy in small molecule systems. However, there are long molecular chains in polymer systems that can accelerate the movement under the action of absorbing external forces. In other words, macromolecular chains can be activated by external forces. Macromolecule chains break at stress concentrations to generate free radicals, thereby triggering macromolecular reactions. Polymer chemistry has become an important branch of polymer chemistry. In this regard, Xu Wei and others carried out pioneering research work. The grinding disk reactor created on the basis of studying the principle of grinding of ancient stone mills in China has become a new research method of polymer chemistry. The use of disc reactors successfully comminuted a flexible PE. The disc disc reactor has been used in many applications. For example, grinding can improve the thermal stability of PVC, improve the processability and impact toughness of PS-Ti2 systems, and prepare PP and The maleic anhydride grafted polymer thus incorporates an electro-acoustic transducer made of a counter piezoelectric material on the PP chain, and has a simple structure and a shape-responsive group. The use of vibratory ball milling can realize the pow- erization of PVC Wen Qingzhen et al.: Degradation of energy conversion in polymer media, and obtain low molecular weight PVC with a large specific surface area, in order to achieve PVC self-molding, improve PVC mechanical properties, and improve PVC Processing performance provides a new way. Polymeric chemical reactions can be carried out in solution or in the melt. An interesting example is the block copolymer of tile 0 and PAM obtained by high-speed stirring (20001') in a mixed solution of PEO and PAM.

8 Acoustic energy change Learn how sound waves can be transmitted to macromolecule media under the right conditions to cause movement of macromolecular chains. Ultrasound (frequency 2X14Hz 109Hz) can form vacuoles (cavitation) in the solution, can crushed solid particles, can cause free radicals in the polymer medium or solution to initiate degradation, copolymerization, crosslinking and other polymer reactions. Ultrasonic chemistry also belongs to the category of macromolecular force chemistry. Through ultrasound irradiation, about 20 kinds of block or graft copolymers that are difficult to synthesize using general methods are synthesized in the State Key Laboratory of Polymer Materials Engineering to polymerize polymers. The existing varieties of the material and the new varieties that are expected to emerge are greatly increased. Ultrasonic irradiation can also initiate emulsion polymerization, without the need of conventional chemical initiators, low reaction temperature, small latex particle size, uniform distribution, high reaction rate, and high molecular weight of the obtained polymer, which is a new method of emulsion polymerization. Ultrasonic irradiation can improve the mechanical properties of the resin/inorganic filler system, and the ultrasonic vibration stress field is introduced into the polymer extrusion process to reduce the extrusion pressure, reduce the apparent viscosity and apparent viscous flow activation energy, and increase the extrusion yield. The polymer-filler nanocomposite system was prepared by ultrasonic irradiation of microemulsion to prepare polymer nanoparticles, which is an important innovation.

9 Electromagnetic radiation energy change Academic energy The wavelength of electromagnetic radiation covers a wide range. From radio long wave to C ray, it can be converted into chemical energy through a polymer medium. Electromagnetic waves with a wavelength less than micron, including microwave, infrared, visible light, ultraviolet rays , X-rays and C-rays.

The polymer medium absorbs light energy and converts it into chemical energy, generating macromolecular free radicals to initiate macromolecular reactions such as polymerization, grafting, degradation, and cross-linking. In order to solve the 'white pollution', exploring ways to control photodegradation is of interest. Microwaves produce thermal and chemical effects in polymeric media that can improve the interfacial compatibility of polyolefin-filler systems, resulting in a significant increase in the macro-mechanical properties of the product. The State Key Laboratory of Polymer Materials has achieved a number of achievements in the irradiation capacity of polymer blend systems. The use of different wavelengths of electromagnetic waves (microwaves, ultraviolet rays, C rays) and electron beams to irradiate polyolefin materials in air, oxygen, and ozone has been studied, and carbonyl groups, hydroxyl groups, carboxyl groups, etc. have been successfully and conveniently introduced into macromolecular chains. Oxygen-containing polar groups improve the compatibility of such inexpensive large-scale plastics with engineering plastics and inorganic fillers, and provide a new way to achieve high performance of polyolefin materials.

Polymeric materials are one of the most important functional materials in development. They have been widely used in high-tech fields, especially in the military field. The mechanism and different forms of energy conversion in polymer media are important theoretical fields to be studied in depth. In the future, we should continue to study the relationship between macromolecule structure and energy conversion performance, and lay a theoretical foundation for the molecular design of highly efficient transduction materials. Another important research direction is the composite technology of polymer materials and other transducing materials. Polymers are used as binders, and different functional materials are combined to exert a synergistic effect between polymer materials and other materials. The field of application of polymer transducing materials also needs to be expanded. It can not only make full use of the energy conversion efficiency, but also give full play to the unique properties and advantages of polymer materials, such as light weight, flexibility, water resistance, corrosion resistance, film formation, spinning, easy processing and molding. It is believed that its importance and application areas will continue to grow.