Necessity and feasibility of new polymerization methodology research for China's high-performance polyolefin technology development

Polyolefins composed predominantly of polyethylene (PE) and polypropylene (PP) are the largest-volume polymer materials in the world, thanks to their abundant monomer resources and efficient and highly scalable production methods. Polyolefins are light-weight, durable, and nonpoisonous, which earn them widespread applications in nearly all walks of life. Though commonly conceived as commodity polymers, polyolefins are increasingly used in specialty sectors such as health, safety, and energy. With vast population base and rapid economic growth, China has been and will continue to be the world's largest consumer market for polyolefins in the foreseeable future. To meet the market demand, China has greatly expanded its polyolefin industry by adding millions of tons of production capacity in recent years. Such an effort has established the industry among its global peers as the largest in production volume and the most diverse in polymerization technology. Despite the various advantages it enjoys, China polyolefin industry has long suffered from technological backwardness, the most prominent of which are in the sectors of catalyst and polymerization technology. After generations of development, China's Ziegler-Natta catalysts are now among the world's best for PE and PP production. However, compared with polyolefin industries in Europe, Japan, and the United States, China's polyolefin industry has been left much behind in the development of metallocene catalysts that are commonly viewed as the catalysts for advanced, high-end polyolefins. Nowadays metallocene catalyst technology has been largely mature in western polyolefin industries, allowing them to be able to extensively exploit the catalysts to produce high value-added polyolefin products such as long-chain-branched PP (LCB-PP), polyolefin plastomers (POP), and polyolefin elastomers (POE). In contrast, China's polyolefin industry is still struggling with self-sufficiency of metallocene catalysts and their key component MAO, far less from adroitly employing them in development of advanced polyolefins. China's vast polyolefin production capacity is overwhelmingly built upon imported polymerization technologies licensed by western companies, which are designed mainly for production of general-purpose polyolefin products. With difficulties in obtaining the licensing right, the core of olefin polymerization technology, the catalloy technology for in situ production of polyolefin thermoplastic elastomers (rTPO) that extend polyolefin applications from plastics to elastomers, has yet to be in service in China. China's polyolefin industry also lacks solution polymerization technology, which hampers domestic production of metallocene-based advanced polyolefins including POE and POP. As a result of the technological inadequacies, China's polyolefin industry has long faced structural disproportionality, i.e. excess of general-grade products with high dependency on importing high-end products. To effectively tackle the issue in a timely fashion, I propose in this commentary that, alongside the important catalyst and polymerization technology development, new olefin polymerization methodology research should also be given its fair share of attention, which has the potential to provide unconventional opportunities for high-performance polyolefin development based on existing Ziegler-Natta catalysts and polymerization technologies available to China's polyolefin industry. As a manifestation of such a proposition, I introduce a Simultaneous/In-Situ Crosslinking Olefin Polymerization (S/ICOP) technology that has succeeded with rTPO and LCB-PP preparation. In future development, S/ICOP technology may be combined with metallocene catalysts to continue to propel China's polyolefin technology advancement.

Automated summary

Polyolefins, such as polyethylene and polypropylene, are the largest-volume polymer materials in the world. China is the largest consumer market for polyolefins, but its polyolefin industry lags behind in terms of catalyst and polymerization technology, leading to a heavy reliance on imported advanced products. To address this issue, new olefin polymerization methods should be researched alongside catalyst and technology development.