■ | of information sources Sinopec Magazine
Sinopec has established the vision and goal of building the world's leading clean energy chemical company, building an industrial pattern of "one base, two wings and three new", and implementing the world's leading development strategy. A leading company should have a large number of original technologies and products. Can Sinopec develop original technologies with global influence in the polymer materials industry? Taking history as a mirror, we try to find the answer from the history of polymer materials science and industrial development.
In 1920, the famous German chemist Hermann Staudinger published a paper entitled "On Polymerization", proposing the concept of polymers, and polymer science was born. In the following 100 years, a total of 8 polymer scientists won 5 Nobel Prizes, and the polymer materials industry was also promoted by scientific research to create the polymer world before 1970. Dozens of polymer materials, including polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC) and polystyrene (PS), including plastics, rubber and fibers, have achieved large-scale industrialization and are known as the first revolution in the polymer materials industry. Since then, there have been few major breakthroughs in polymer materials science and technology that have benefited mankind.
In 1997, the damage to the environment caused by plastic floating matter in the ocean was discovered and reported, which seriously affected the development of the polymer materials industry and became the biggest challenge facing the polymer materials industry.
At present, the second revolution in polymer materials science and industry is emerging. This revolution will bring the polymer materials industry into a circular economy model, providing us with the opportunity to leapfrog development and become a leading producer of synthetic materials.
The circular development of polymer materials includes two modes: "biological cycle" and "technical cycle".
"Biocirculation" refers to the biodegradable bio-based polymer material that is degraded into carbon dioxide and water after use, and then converted into biomass that can be prepared as a polymer material through photosynthesis. Regrettably, the scientific and technical issues of the relevant materials have not yet been resolved. Bio-based polymers such as polylactic acid are too high to degrade in the natural environment, can only be degraded under 60 degrees Celsius composting conditions, can not be applied on a large scale, is not the fundamental way to solve white pollution; PBAT and PBST and other low glass temperature materials can be degraded under 25 degrees Celsius composting conditions, but it is difficult to use bio-based monomer preparation, and the problem of poor mechanical properties and high cost makes its application limited. These scientific and technological challenges are precisely the opportunities for us to achieve leapfrog development. Sinopec has been conducting years of research on degradable polymer materials, has a certain amount of technology accumulation, should continue to carry out basic research and technology development, and strive to take the lead in developing bio-based polymer materials with excellent performance and degradable under non-composting conditions, and become a technology leader in this field.
"Technology recycling" mainly refers to recycling, including physical reuse and chemical reuse of the two development directions. The world's largest polymer materials companies generally regard the technology cycle as the main way to solve the problem of white pollution.
Physical circulation refers to the same type of polymer materials after recycling and reuse, is currently widely used in a way, the method recovers less than 9% of the consumption of polymer materials, the need to develop more advanced technology. In the face of the classification difficulties encountered in the recycling of multi-component polymer materials, Sinopec Beijing Research Institute of Chemical Industry has carried out some innovative explorations in the aspect of "compatibilizer", hoping to solve the compatibility problem of a variety of component polymer materials when polymer products are reused, so that waste polymer materials are not classified when recycled, and the mechanical properties of recycled materials do not drop but rise. We invented a new polymer grafting method called the "high-temperature solid phase grafting method."
Using this method, under the action of microwaves, maleic anhydride can be grafted onto polypropylene, and maleic acid or sodium maleate grafted polypropylene can be prepared. The test results show that the mechanical strength and thermal properties of the graft are better than those of polypropylene before grafting. The structural characterization results show that the prepared graft polypropylene is a high melt strength polar polypropylene. As a "special compatibilizer", these resins can be applied to the direct recycling of multi-component products. The use of solid phase grafting method in polypropylene micropores, can also be made of super hydrophilic materials, applied to water conservancy engineering and cool water towers and other aspects is expected to greatly reduce the evaporation of water; superphilic polypropylene products can also be used "glue" to achieve bonding; polypropylene superphilic water hollow fiber is also expected to be used to make ultrafiltration membranes for sewage treatment. Chemical reuse is to degrade waste polymer materials into monomers, and then polymerize into new polymer materials, which is the future of the circular development of polymer materials.
Chemical reuse mainly includes two development directions, high temperature degradation and catalytic degradation. The traditional high-temperature degradation is carried out below 800 degrees Celsius, and only oil products can be obtained, which is economically unreasonable. Catalytic degradation can degrade polymer materials into monomers at lower temperatures, but the reaction conditions are very harsh and have not yet reached the level of industrialization. The microwave-assisted pyrolysis method we invented can heat polymer materials to more than 1000 degrees Celsius under non-oxidation conditions, so that they can be degraded into monomers under non-catalytic conditions, which has a good industrial prospect. After microwave pyrolysis of polyolefin materials, palm oil, waste plastic oil, and a variety of hazardous wastes, a mixture of gases mainly based on ethylene and propylene was obtained. The method is also suitable for the high-temperature cracking of waste biomass such as straw and branches, which can obtain hydrogen-rich syngas, which can be prepared from hydrocarbons or methanol, and polymerized after further preparation of olefins to obtain polymer materials. It is conceivable that by adding a microwave cracking system in front of the ethylene cracking device, the current traditional petrochemical or coal chemical industry can be turned into a waste plastic recycling or biochemical device, which can achieve "turning waste into treasure" and forming a new cycle. Catalytic technology is the dominant field of Sinopec, and we have great hopes for a major breakthrough in the chemical recycling of waste polymer materials. Once the chemical reuse of waste polymer materials makes breakthrough progress, fossil-based polymer materials will usher in new development opportunities.
At present, the global consumption of polyolefins is nearly 200 million tons, accounting for 71% of plastic consumption and 52% of the consumption of the three major synthetic materials. China's polyolefin industry has developed rapidly, has become the world's largest producer and consumer, Sinopec has also become the world's largest polyolefin producer, the production capacity is about to exceed 20 million tons. Therefore, the continuous strengthening of innovation in polyolefins is crucial to the development of Sinopec. Sinopec has conducted in-depth research on the core technologies and key scientific issues of polyolefins and has achieved a number of innovative achievements.
In terms of polypropylene, a number of original innovative products have been developed, such as low solubles transparent polypropylene resin, high melt strength impact resistant polypropylene resin, polypropylene resin for high breakdown voltage resistant film, and antibacterial and antifungal polypropylene resin. At present, China's polypropylene foreign dependence is less than 18%, but the import volume of polyethylene is still more than 40%, some key technologies still rely on imports, and many high-performance products have not yet achieved localization. Some of the high-pressure polyethylene products and solution polymerization products such as POE are completely dependent on imports. Therefore, Sinopec has many innovation opportunities in polyethylene technology and product innovation. Looking back at the development process of the polyolefin industry, we can deeply appreciate that for original inventions, processing applications and process development are indispensable. In 1931, polyisobutene (PIB) was commercialized, thus unveiling the history of polyolefins. The process of polyethylene from invention, industrialization to commercialization is quite tortuous, under the efforts of DuPont, the British Imperial Chemical Industry Group (ICI), Lian Carbon and other companies, through the breakthrough of technology development, process development, processing and application, high-pressure polyethylene took the lead in industrialization. Subsequently, low-pressure polyethylene and linear low-density polyethylene have also been industrialized.
Looking at the current polyolefin field, there are three aspects of innovation opportunities.
The first is localization through disruptive innovation. It mainly includes the industrialization of precipitated polymerization instead of solution polymerization to achieve the industrialization of POE (ethylene octene copolymer), ultra-high molecular weight polyethylene, salin (copolymer of ethylene and acrylate), etc.; the use of low-pressure polymerization instead of high-pressure polymerization to achieve special EVA (ethylene-vinyl acetate copolymer), EVOH (ethylene-vinyl alcohol copolymer), sarin (ethylene-unsaturated ester copolymer), etc.; the preparation and application of polypropylene "wood", etc.
The second is to research and develop high-end synthetic resin products. One of the key points is polyolefin engineering plastics, mainly PMP (poly-4 methyl 1 pentene), COP (thermoset cycloolefin polymer), COC (cyclic olefin copolymer) and sarin and other 4 types of materials. The second key point is to strengthen and expand the products that Sinopec already has original technology, such as nylon 6 and PET engineering plastics.
The third is to commercialize new materials that Sinopec already has r&D foundations through cooperation. It mainly includes three aspects, one is the copolymer microspheres of maleic anhydride and olefins; the second is structural innovation of nylon 6 to expand the application field of nylon 6, such as agricultural greenhouse film, food packaging film, etc.; the third is to reduce the cost of artificial "wood" through collaborative innovation, research and development of ultra-hydrophilic polypropylene materials, soft and transparent medical polypropylene, anti-viral polypropylene non-woven fabrics, ultra-high pressure polypropylene cable materials, etc., to prevent polypropylene overcapacity. It should be emphasized that the development of new polymer materials is a work chain that includes structural performance characterization, small test, pilot test, processing, industrial application test, market development and other links, technological innovation requires multidisciplinary coordination of polymer physics, catalysis, processing and application, etc. Must establish a team culture and corresponding management mechanism in order to have more and more original innovation results and achieve leapfrog development.