Page 70 - Demo

68 Eyl%u00fcl - September / Ekim - October 2024 limerize eden) ve bunlar%u0131 yeni PUR %u00fcr%u00fcnlerinde hammadde olarak yeniden kullanmak amac%u0131yla k%u00fc%u00e7%u00fck ama b%u00fcy%u00fcyen bir end%u00fcstrinin varl%u0131%u011f%u0131 s%u00f6z konusudur.Yine de, %u00e7%u0131kt%u0131lar%u0131n%u0131n %u201ci%u015flenmemi%u015f%u201d malzemelerle ger%u00e7ekten rekabet edebilmesi i%u00e7in gidilmesi gereken uzun bir yol var. %u0130stenen elementleri ay%u0131rmak ve safla%u015ft%u0131rmak maliyetlidir.Tek seferde par%u00e7alama ve ay%u0131rma%u0130%u015fte bu noktada Aarhus %u00dcniversitesi'nden bir ara%u015ft%u0131rma ekibi ak%u0131ll%u0131ca bir fikirle devreye giriyor. Y%u00f6ntemlerini, s%u00f6z konusu %u015firketlerin halihaz%u0131rda kulland%u0131%u011f%u0131, PUR k%u00f6p%u00fc%u011f%u00fcn%u00fc asitle par%u00e7alama (asidoliz) y%u00f6ntemine dayand%u0131r%u0131yorlar.Ancak %u015firketler par%u00e7alanan PUR'u poliol ve izosiyanat olarak ay%u0131rmamaktad%u0131r. Bu da do%u011frudan geri d%u00f6n%u00fc%u015ft%u00fcr%u00fclemeyen ancak m%u00fc%u015fterilerinin yeni tarifler kullanmas%u0131n%u0131 gerektiren bir kar%u0131%u015f%u0131m%u0131n olu%u015fmas%u0131na neden olmaktad%u0131r.AU ara%u015ft%u0131rmac%u0131lar%u0131 sadece PUR'u par%u00e7alay%u0131p iki ana bile%u015feni ay%u0131rmakla kalm%u0131yor, bunu tek seferde yapabiliyorlar. Esnek PUR k%u00f6p%u00fc%u011f%u00fcn%u00fc bir miktar s%u00fcksinik asit i%u00e7eren bir reakt%u00f6rde 220%u00b0C'ye kadar %u0131s%u0131t%u0131yorlar (bilgi kutusuna bak%u0131n%u0131z). Daha sonra, bir malzemeyi yakalayan ve di%u011ferinin ge%u00e7mesini sa%u011flayan bir filtre kullan%u0131yorlar.Filtreden ge%u00e7en poliollerdir ve bunu i%u015flenmemi%u015f poliollerle kar%u015f%u0131la%u015ft%u0131r%u0131labilir bir kalitede yaparak yeni poli%u00fcretan %u00fcretiminde kullan%u0131lmalar%u0131n%u0131 m%u00fcmk%u00fcn k%u0131larlar. Filtrelenen %u00fcr%u00fcn kar%u0131%u015f%u0131m%u0131n%u0131n kat%u0131 k%u0131sm%u0131, basit bir hidroliz i%u015flemiyle diamin olarak adland%u0131r%u0131lan ve izosiyanatlar%u0131n ve dolay%u0131s%u0131yla PUR'un %u00fcretiminde kullan%u0131lan bir maddeye d%u00f6n%u00fc%u015ft%u00fcr%u00fcl%u00fcr.Bu %u015fekilde ara%u015ft%u0131rmac%u0131lar, diamin ve poliollerin iki ayr%u0131 fraksiyonu olarak yataklarda kullan%u0131lan esnek PUR k%u00f6p%u00fckten orijinal malzemenin a%u011f%u0131rl%u0131k%u00e7a y%u00fczde 82'sine kadar%u0131n%u0131 geri kazanabiliyorlar. Ara%u015ft%u0131rmac%u0131lar bulgular%u0131n%u0131 k%u0131sa s%u00fcre %u00f6nce Green Chemistry dergisinde yay%u0131nlad%u0131.Ara%u015ft%u0131rmac%u0131lar %u015fu an yeni teknolojiyi di%u011fer poli%u00fcretan malzemeler %u00fczerinde test ederek bunlar%u0131n nas%u0131l geri d%u00f6n%u00fc%u015ft%u00fcr%u00fclebilece%u011fini ara%u015ft%u0131r%u0131yor. Ayr%u0131ca prosesin bir par%u00e7as%u0131 olan dikarboksilik asidin nas%u0131l yeniden kullan%u0131labilece%u011fi %u00fczerinde de %u00e7al%u0131%u015f%u0131yorlar. Bunun d%u0131%u015f%u0131nda teknolojinin ger%u00e7ekten d%u00f6ng%u00fcsel bir ekonomi yaratabilece%u011fini g%u00f6stermek i%u00e7in geri d%u00f6n%u00fc%u015ft%u00fcr%u00fclm%u00fc%u015f malzemeleri yeni %u00fcr%u00fcnler olu%u015fturmak %u00fczere test edecekler.Still, there is a long way to go before their output can actually compete with \separate and purify the desired elements.Breaking down and separating in one goThis is where a research team from Aarhus University comes in with a smart idea. They base their method on what the companies in question already use, namely breaking down PUR foam with acid (acidolysis).But the companies do not separate the broken-down PUR into polyol and isocyanate. This results in a mixture that cannot be directly recycled but requires their customers to use new recipes.The AU researchers are not only able to break down PUR and separate the two main components%u2014they can do it in one go. They heat flexible PUR foam to 220%u00b0C in a reactor with a bit of succinic acid (see fact box). Afterwards, they use a filter that catches one material and lets the other pass through.It is the polyols that pass through, and they do so in a quality comparable to virgin polyol, making it possible to use them in new production of polyurethane. The solid part of the product mixture that is filtered out is transformed into a so-called diamine in a simple hydrolysis process, which is used in the production of isocyanates and thus PUR.In this way, the researchers are able to recover up to 82 weight percent of the original material from flexible PUR foam%u2014used in mattresses%u2014as two separate fractions of diamines and polyols. The researchers have recently published their findings in the journal Green Chemistry.Right now, the researchers are testing the new technology on other polyurethane materials to see how these can be recycled. They are also investigating how the dicarboxylic acid, which is part of the process, can be reused. Additionally, they will test the recycled materials to create new products to show that the technology can truly create a circular economy.Journal Reference: Thomas B. Bech et al, Chemical separation of polyurethane via acidolysis %u2013 combining acidolysis with hydrolysis for valorisation of aromatic amines, Green Chemistry (2024). DOI: 10.1039/D4GC00819GBilimsel / ScientificKaynak / Source: https://phys.org/news/2024-08-smarter-recycle-polyurethane.html