{"id":105182,"date":"2024-08-31T11:06:57","date_gmt":"2024-08-31T07:36:57","guid":{"rendered":"https:\/\/polymervapooshesh.ir\/?p=105182"},"modified":"2024-09-08T14:25:56","modified_gmt":"2024-09-08T10:55:56","slug":"105182","status":"publish","type":"post","link":"https:\/\/polymervapooshesh.ir\/en\/105182\/","title":{"rendered":"Berkeley scientists develop polyolefin depolymerisation technology"},"content":{"rendered":"

Iranpolymer\/Baspar <\/strong><\/em>Scientists at the University of California, Berkeley have developed a depolymerisation technology to chemically recycle polyolefins.<\/p>\n

In a new paper, the team described the method as a scalable, energetically and environmentally viable solution to hard-to-recycle plastics. Unlike pyrolysis, the chemical recycling method often used for polyolefins, the new process uses a comparatively low temperature of 320 C.<\/p>\n

The process showed yields of 81% for waste LDPE, 93% for HDPE, and over 95% for PP, including post-consumer forms of these materials.<\/p>\n

The academics synthesised two catalysts, one of sodium on alumina and another of tungsten oxide on silica. They found that the first catalyst efficiently broke or cracked ethylene polymer chains, leaving one of the two pieces with a reactive carbon-carbon double bond at the end. The second, in turn, added the carbon atom at the end of the chain to ethylene gas, which the scientists constantly streamed through the reaction chamber, to form a propylene molecule. When applied to PP, the process produced the propylene monomer in combination with a hydrocarbon called isobutylene.<\/p>\n

\u201cYou can\u2019t get much cheaper than sodium,\u201d John Hartwig, a UC Berkeley professor of chemistry who led the research said in a statement. \u201cAnd tungsten is an earth-abundant metal used in the chemical industry in large scale. This combination of tungsten oxide on silica and sodium on alumina is like taking two different types of dirt and having them together disassemble the whole polymer chain into even higher yields of propene from ethylene and a combination of propene and isobutylene from polypropylene than we did with more complex, expensive catalysts.\u201d<\/p>\n

The team also tested adding plastic additives and different types of plastics to the reaction chamber to see how the catalytic reactions were affected by contaminants. They found that small amounts of these impurities barely affected the conversion efficiency, but small amounts of PET and PVC significantly reduced the efficiency. This may suggest that a scaled-up version of this technology requires separation of plastic waste, as already happens with other high-yield chemical recycling technologies.<\/p>\n

\u201cWe have an enormous amount of polyethylene and polypropylene in everyday objects, from lunch bags to laundry soap bottles to milk jugs \u2014 so much of what\u2019s around us is made of these polyolefins,\u201d Hartwig said.\u00a0\u201cWhat we can now do, in principle, is take those objects and bring them back to the starting monomer by chemical reactions we\u2019ve devised that cleave the typically stable carbon-carbon bonds. By doing so, we\u2019ve come closer than anyone to give the same kind of circularity to polyethylene and polypropylene that you have for polyesters in water bottles,\u201d he added.<\/p>\n

Hartwig\u2019s team shared its findings in \u2018Polyolefin waste to light olefins with ethylene and base-metal heterogeneous catalysts\u2019, recently published in\u00a0Science<\/i>.<\/p>\n

sustainableplastics<\/em><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

Iranpolymer\/Baspar Scientists at the University of California, Berkeley have developed a depolymerisation technology to chemically recycle polyolefins. In a new paper, the team described the method as a scalable, energetically and environmentally viable solution to hard-to-recycle plastics. Unlike pyrolysis, the chemical recycling method often used for polyolefins, the new process uses a comparatively low temperature …<\/p>\n","protected":false},"author":5,"featured_media":105183,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","footnotes":""},"categories":[69],"tags":[45253,49236,57029,1002,51910,2485,2138,2162,1272,1846],"class_list":["post-105182","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news-en","tag-chemical-recycling","tag-depolymerisation","tag-hard-to-recycle-plastics","tag-pet","tag-plastic-additives","tag-polyesters","tag-polyolefin","tag-polypropylene","tag-pvc","tag-silica"],"_links":{"self":[{"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/posts\/105182","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/comments?post=105182"}],"version-history":[{"count":0,"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/posts\/105182\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/media\/105183"}],"wp:attachment":[{"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/media?parent=105182"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/categories?post=105182"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/polymervapooshesh.ir\/en\/wp-json\/wp\/v2\/tags?post=105182"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}