Biodegradable plastics yog tshaj tawm ua ib qho ntawm kev daws teeb meem rau cov teeb meem yas paug uas ua rau thoob ntiaj teb, tab sis hnub no" compostable" hnab yas, tais diav thiab tais diav yuav tsis yaj thaum lub sij hawm ua kom xau, thiab yuav paug lwm yam khoom coj mus siv. Plastics ua teeb meem rau cov neeg rov coj mus ua dua tshiab. Cov plua tshauv plua plav feem ntau yog ua los ntawm cov polyester hu ua polylactic acid (PLA), uas yog thaum kawg muab pov tseg, thiab nws lub neej ntev li ntev li plastics tas.
Cov kws tshawb fawb hauv University of California, Berkeley tam sim no tau tsim ib txoj hauv kev los ua kom cov av ua txab no ua kom yooj yim dua rau kev xaim. Lawv tuaj yeem decomposed nyob rau hauv ob peb lub lis piam nrog tsuas yog cua sov thiab dej, daws qhov teeb meem uas tau ua rau cov neeg lag luam tsis muaj peev xwm thiab ib puag ncig. Ting Xu, tus xibfwb ntawm lub Department of Material Science thiab Engineering thiab Department of Chemistry ntawm University of California, Berkeley, tau hais tias:" Tib neeg tam sim no npaj hloov mus siv biodegradable polymers los kho cov yas siv ib leeg, tab sis yog tias nws hloov tawm tias nws ua rau muaj teeb meem ntau dua li nws tsim nyog, Tom qab ntawd txoj cai yuav rov qab tsim dua, thiab tam sim no, peb tuaj yeem daws cov teeb meem txuas ntxiv ntawm tsis-biodegradable uas plastics." Xu yog tus kws sau ntawv tshaj xov xwm piav txog cov txheej txheem no, uas yuav tshwm nyob rau hauv phau ntawv Xov Xwm Xwm Xyoo no.
Raws li txoj kev xav, cov thev naus laus zis tshiab no yuav tsum siv tau rau lwm hom polyester yas, thiab tuaj yeem tsim cov ntim yas ntim khoom ntim zom tau. Cov ntim no yog tam sim no ua los ntawm polyethylene, ib qho polyolefin uas tsis cuam tshuam dab tsi. Xu ntseeg hais tias polyolefin plastics tau zoo tshaj plaws hloov mus rau hauv cov khoom lag luam muaj txiaj ntsig ntau dua li sau npe. Nws tab tom kawm paub yuav ua li cas hloov cov khoom qub polyolefin plastics rau hauv kev rov siv dua.
Cov txheej txheem tshiab suav nrog kev cog qoob loo polyester-noj cov enzymes hauv cov yas txheej txheem tsim khoom. Cov enzymes no yog tiv thaiv los ntawm cov txheej polymer yooj yim los tiv thaiv cov enzymes los ntawm kev ua lub siab tsis zoo thiab coj mus siv tsis tau. Thaum raug rau tshav kub thiab dej, qhov enzyme tau tshem ntawm nws cov pob polymer thiab pib ua kom cov yas polymer ua rau nws cov ntu feem. Yog tias muaj cov kua qaub polylactic, nws raug txo kom lactic acid, uas tuaj yeem yog cov av microorganisms hauv cov lwg. Muab cov khoom noj khoom haus. Cov ntawv txheej polymer tseem yuav ua rau xeb.
Txoj kev no tshem tawm cov kab mob me me, uas yog cov khoom lag luam ntawm ntau cov txheej txheem tshuaj lom neeg thiab lawv tus kheej muaj kuab paug. Txog li 98% ntawm cov yas uas siv los siv Xu' s thev naus laus zis yuav hloov mus ua cov roj me me. Ib qho ntawm cov sib koom ua ke ntawm txoj kev tshawb no, Aaron Hall, ib tug qub PhD kawm ntawm University of California, Berkeley, tau tsim ib lub tuam txhab los txuas ntxiv txhim kho cov plhom biodegradable plastics.
Plastics yog tsim los kom tsis decomposed thaum siv, tab sis qhov no kuj txhais tau tias lawv yuav tsis decomposed tom qab tau muab pov tseg. Lub hnab yas khov kho tshaj plaws muaj cov qauv tsim qauv uas yuav luag zoo li crystal. Cov polymer ua raws txheej txheem nruj kom dej tsis tuaj yeem nkag rau lawv, tsis txhob hais txog cov kab mob me me uas yuav tua cov polymer, uas yog cov txheej txheem organic.
Cov enzymes xws li lipase (pob ntsuab) tuaj yeem thuam cov yas polymers los ntawm qhov chaw. Tab sis lawv txiav lub polymer cov saw ntawm yuav, tawm tom qab microplastics. Ib pab pawg ntawm University of California, Berkeley kos cov enzymes thoob plaws cov yas, tiv thaiv los ntawm nanoclusters. Cov roj ntsha enzyme tsau nyob ze rau qhov kawg ntawm cov xov txuas polymer thiab degrades polymer cov pa roj los ntawm qhov kawg hauv qab qhov ua kom kub thiab noo noo. Cov thev naus laus zis no khaws lub siab ntawm cov yas thaum siv, tab sis thaum tus neeg siv depolymerization, cov yas yuav ib txwm ua cov roj me me uas rov ua dua tshiab los ntawm cov khoom lag luam.
