{"id":33959,"date":"2016-03-31T07:20:24","date_gmt":"2016-03-31T05:20:24","guid":{"rendered":"https:\/\/renewable-carbon.eu\/news\/?p=33959"},"modified":"2016-03-30T12:58:29","modified_gmt":"2016-03-30T10:58:29","slug":"ornl-researchers-invent-tougher-plastic-with-50-percent-renewable-content","status":"publish","type":"post","link":"https:\/\/renewable-carbon.eu\/news\/ornl-researchers-invent-tougher-plastic-with-50-percent-renewable-content\/","title":{"rendered":"ORNL researchers invent tougher plastic with 50 percent renewable content"},"content":{"rendered":"
\"16-G00184_VerB\"
ORNL\u2019s tough new plastic is made with 50 percent renewable content from biomass. Image credit: Oak Ridge National Laboratory, U.S. Dept. of Energy; conceptual art by Mark Robbins<\/figcaption><\/figure>\n

OAK RIDGE, Tenn., March 22, 2016\u2014Your car\u2019s bumper is probably made of a moldable thermoplastic polymer called ABS, shorthand for its acrylonitrile, butadiene and styrene components. Light, strong and tough, it is also the stuff of ventilation pipes, protective headgear, kitchen appliances, Lego bricks and many other consumer products. Useful as it is, one of its drawbacks is that it is made using chemicals derived from petroleum.
\n<\/strong>
\n\"16-G00181_Schematic_A\"Now, researchers at the Department of Energy\u2019s Oak Ridge National Laboratory have made a better thermoplastic by replacing styrene with lignin, a brittle, rigid polymer that, with cellulose, forms the woody cell walls of plants. In doing so, they have invented a solvent-free production process that interconnects equal parts of nanoscale lignin dispersed in a synthetic rubber matrix to produce a meltable, moldable, ductile material that\u2019s at least ten times tougher than ABS. The resulting thermoplastic\u2014called ABL for acrylonitrile, butadiene, lignin\u2014is recyclable, as it can be melted three times and still perform well. The results, published in the journal Advanced Functional Materials<\/em><\/a>, may bring cleaner, cheaper raw materials to diverse manufacturers.<\/p>\n

\u201cThe new ORNL thermoplastic has better performance than commodity plastics like ABS,\u201d said senior author Amit Naskar in ORNL\u2019s Materials Science and Technology Division, who along with co-inventor Chau Tran has filed a patent application for the process to make the new material. \u201cWe can call it a green product because 50 percent of its content is renewable, and technology to enable its commercial exploitation would reduce the need for petrochemicals.\u201d<\/p>\n

The technology could make use of the lignin-rich biomass byproduct stream from biorefineries and pulp and paper mills. With the prices of natural gas and oil dropping, renewable fuels can\u2019t compete with fossil fuels, so biorefineries are exploring options for developing other economically viable products. Among cellulose, hemicellulose and lignin, the major structural constituents of plants, lignin is the most commercially underutilized. The ORNL study aimed to use it to produce, with an eye toward commercialization, a renewable thermoplastic with properties rivaling those of current petroleum-derived alternatives.<\/p>\n

To produce an energy-efficient method of synthesizing and extruding high-performance thermoplastic elastomers based on lignin, the ORNL team needed to answer several questions: Can variations in lignin feedstocks be overcome to make a product with superior performance? Can lignin integrate into soft polymer matrices? Can the chemistry and physics of lignin-derived polymers be understood to enable better control of their properties? Can the process to produce lignin-derived polymers be engineered?<\/p>\n

\u201cLignin is a very brittle natural polymer, so it needs to be toughened,\u201d explained Naskar, leader of ORNL\u2019s Carbon and Composites group. A major goal of the group is producing industrial polymers that are strong and tough enough to be deformed without fracturing. \u201cWe need to chemically combine soft matter with lignin. That soft matrix would be ductile so that it can be malleable or stretchable. Very rigid lignin segments would offer resistance to deformation and thus provide stiffness.\u201d<\/p>\n

All lignins are not equal in terms of heat stability. To determine what type would make the best thermoplastic feedstock, the scientists evaluated lignin from wheat straw, softwoods like pine and hardwoods like oak. They found hardwood lignin is the most thermally stable, and some types of softwood lignins are also melt-stable.<\/p>\n

Next, the researchers needed to couple the lignin with soft matter. Chemists typically accomplish this by synthesizing polymers in the presence of solvents. Because lignin and a synthetic rubber containing acrylonitrile and butadiene, called nitrile rubber, both have chemical groups in which electrons are unequally distributed and therefore likely to interact, Naskar and Chau Tran (who performed melt-mixing and characterization experiments) instead tried to couple the two in a melted phase without solvents.<\/p>\n

In a heated chamber with two rotors, the researchers \u201ckneaded\u201d a molten mix of equal parts powdered lignin and nitrile rubber. During mixing, lignin agglomerates broke into interpenetrating layers or sheets of 10 to 200 nanometers that dispersed well in and interacted with the rubber. Without the proper selection of a soft matrix and mixing conditions, lignin agglomerates are at least 10 times larger than those obtained with the ORNL process. The product that formed had properties of neither lignin nor rubber, but something in between, with a combination of lignin\u2019s stiffness and nitrile rubber\u2019s elasticity.<\/p>\n

By altering the acrylonitrile amounts in the soft matrix, the researchers hoped to improve the material\u2019s mechanical properties further. They tried 33, 41 and 51 percent acrylonitrile and found 41 percent gave an optimal balance between toughness and stiffness.<\/p>\n

Next, the researchers wanted to find out if controlling the processing conditions could improve the performance of their polymer alloy. For example, 33 percent acrylonitrile content produced a material that was stretchy but not strong, behaving more like rubber than plastic. At higher proportions of acrylonitrile, the researchers saw the materials strengthen because of the efficient interaction between the components. They also wanted to know at what temperature the components should be mixed to optimize the material properties. They found heating components between 140 and 160 degrees Celsius formed the desired hybrid phase.<\/p>\n

Using resources at ORNL including the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility, the scientists analyzed the morphologies of the blends. Scanning electron microscopy, performed by Chau Tran, explored the surfaces of the materials. Jihua Chen and Tran characterized soft matter phases using transmission electron microscopy, placing a thin slice of material in the path of an electron beam to reveal structure through contrast differences in the lignin and rubber phases. Small-angle x-ray scattering by Jong Keum revealed repeated clusters of certain domain or layer sizes. Fourier transform infrared spectroscopy identified chemical functional groups and their interactions.<\/p>\n

Future studies will explore different feedstocks, particularly those from biorefineries, and correlations among processing conditions, material structure and performance. Investigations are also planned to study the performance of ORNL\u2019s new thermoplastic in carbon-fiber-reinforced composites.<\/p>\n

\u201cMore renewable materials will probably be used in the future,\u201d Naskar said. \u201cI\u2019m glad that we could continue work in renewable materials, not only for automotive applications but even for commodity usage.\u201d<\/p>\n

The title of the paper is \u201cA New Class of Renewable Thermoplastics with Extraordinary Performance from Nanostructured Lignin-Elastomers.\u201d<\/p>\n

ORNL\u2019s Technology Innovation Program, which reinvests royalties from the lab\u2019s patents in innovative, commercially promising projects, sponsored the study. The researchers conducted polymer characterization experiments (microscopy and X-ray scattering) at the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility at ORNL.<\/p>\n

UT-Battelle manages ORNL for DOE\u2019s Office of Science. The single largest supporter of basic research in the physical sciences in the United States, the Office of Science is working to address some of the most pressing challenges of our time.<\/p>\n","protected":false},"excerpt":{"rendered":"

OAK RIDGE, Tenn., March 22, 2016\u2014Your car\u2019s bumper is probably made of a moldable thermoplastic polymer called ABS, shorthand for its acrylonitrile, butadiene and styrene components. Light, strong and tough, it is also the stuff of ventilation pipes, protective headgear, kitchen appliances, Lego bricks and many other consumer products. Useful as it is, one of […]<\/p>\n","protected":false},"author":59,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","nova_meta_subtitle":"","footnotes":""},"categories":[5572],"tags":[5838,5847,11828],"supplier":[12078,2437,4116,10515],"class_list":["post-33959","post","type-post","status-publish","format-standard","hentry","category-bio-based","tag-bioeconomy","tag-bioplastics","tag-lignin","supplier-advanced-functional-materials","supplier-oak-ridge-national-laboratory","supplier-us-doe-office-of-science-sc","supplier-ut-battelle"],"_links":{"self":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/33959","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/users\/59"}],"replies":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/comments?post=33959"}],"version-history":[{"count":0,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/33959\/revisions"}],"wp:attachment":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media?parent=33959"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/categories?post=33959"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/tags?post=33959"},{"taxonomy":"supplier","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/supplier?post=33959"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}