Anyone who uses products made of plastic. The new recyclable plastic could be a good alternative to many nonrecyclable plastics in use today.
All plastics — from water bottles to automobile parts — are made up of large molecules called polymers, which are composed of repeating units of shorter carbon-containing compounds called monomers. During processing at recycling plants, plastics with different chemical compositions are mixed together and ground into bits. When chopped-up plastic is melted to make a new material, it’s hard to predict which properties it will inherit from the original plastics. This has prevented plastic from becoming a “circular” material whose original monomers can be recovered for reuse for as long as possible, or “upcycled” to make a new, higher-quality product. The new plastic, called poly(diketoenamine), or PDK, can be disassembled into its constituent parts at the molecular level and then reassembled into a different shape, texture, and color again and again without loss of performance or quality. With PDKs, the bonds of conventional plastics are replaced with reversible bonds that allow the plastic to be recycled more effectively. Unlike conventional plastics, the monomers of PDK plastic could be recovered and freed from any compounded additives simply by dunking the material in a highly acidic solution. The acid helps to break the bonds between the monomers and separate them from the chemical additives that give plastic its look and feel.
Lawrence Berkeley National Laboratory, Berkeley, CA
Very few plastics can be recycled without loss in performance or aesthetics. Even the most recyclable plastic, poly(ethylene terephthalate), or PET, is only recycled at a rate of 20 to 30%, with the rest typically going to incinerators or landfills where the carbon-rich material takes centuries to decompose.
The researchers plan to develop PDK plastics with a wide range of thermal and mechanical properties for applications as diverse as textiles, 3D printing, and foams. In addition, they are looking to expand the formulations by incorporating plant-based materials and other sustainable sources. The technology is available for licensing and collaboration.
Mtu yeyote anayetumia bidhaa zilizotengenezwa kwa plastiki. Plastiki hiyo mpya inayoweza kutumiwa tena inaweza kuwa mbadala mzuri wa plastiki nyingi zisizoweza kutumiwa tena zinazotumiwa leo. Plastiki zote, kuanzia chupa za maji hadi sehemu za magari, zimetengenezwa kwa molekuli kubwa zinazoitwa polima, ambazo zinaunganishwa na vipande vya mara kwa mara vya viungo vifupi vyenye kaboni vinavyoitwa monomeri. Wakati wa usindikaji katika viwanda vya kuchakata, plastiki zenye muundo tofauti wa kemikali huchanganywa pamoja na kusaga vipande-vipande. Wakati plastiki iliyokatwa-katwa inapochemshwa ili kutengeneza nyenzo mpya, ni vigumu kutabiri ni mali zipi zitazorithi kutoka kwa plastiki za awali. Hii imezuia plastiki kuwa nyenzo ya mviringo ambayo monomers ya awali inaweza kurudishwa kwa matumizi ya muda mrefu iwezekanavyo, au upcycled kutengeneza bidhaa mpya, ya ubora wa juu. Plastiki hiyo mpya, inayoitwa polydiethylamine (PDK), inaweza kugawanywa katika sehemu zake za msingi katika kiwango cha molekuli na kisha kuunganishwa tena katika umbo, muundo, na rangi tofauti tena na tena bila kupoteza utendaji au ubora. Kwa PDK, vifungo vya plastiki za kawaida huchukuliwa na vifungo vinavyoweza kubadilishwa ambavyo huruhusu plastiki kurejeshwa kwa ufanisi zaidi. Tofauti na plastiki za kawaida, monomers ya plastiki ya PDK inaweza kupatikana na kuachiliwa kutoka kwa nyongeza yoyote ya mchanganyiko kwa kuingiza nyenzo katika suluhisho la asidi sana. Asidi hiyo husaidia kuvunja vifungo kati ya monomeri na kuzitenganisha na viambatisho vya kemikali vinavyotoa plastiki kuonekana na kuhisi. Maabara ya Taifa ya Lawrence Berkeley, Berkeley, CA, ni plastiki chache sana zinazoweza kutumiwa tena bila kupoteza utendaji au urembo. Hata plastiki inayoweza kuyarudishwa, polyethylene terephthalate (PET) ni asilimia 20 hadi 30 tu ya plastiki inayorudishwa, na sehemu iliyobaki kwa kawaida huenda kwenye makaa ya kuchoma au mahali pa kuondoa taka ambapo vifaa vyenye kaboni huchukua karne kuharibika. Kwa hivyo, watafiti wanapanga kuunda plastiki ya PDK na sifa nyingi za joto na mitambo kwa matumizi tofauti kama vile nguo, uchapishaji wa 3D, na povu. Kwa kuongezea, wanaangalia kupanua maandishi kwa kuingiza vifaa vya mimea na vyanzo vingine vya kudumu. Teknolojia inapatikana kwa ajili ya leseni na ushirikiano.