PLA yog dab tsi?
Polylactic acid, tseem hu ua PLA (Polylactic Acid), yog ib qho thermoplastic monomer tau los ntawm cov khoom siv txuas ntxiv dua tshiab xws li pob kws hmoov txhuv nplej siab lossis qab zib los yog beet pulp.
Txawm hais tias nws yog tib yam li yav dhau los plastics, nws cov khoom tau dhau los ua cov peev txheej txuas ntxiv, ua rau nws muaj lwm txoj hauv kev rau fossil fuels.
PLA tseem yog cov pa roj carbon nruab nrab, noj tau, thiab biodegradable, uas txhais tau hais tias nws tuaj yeem decompose tag nrho nyob rau hauv ib puag ncig tsim nyog es tsis txhob tawg mus rau hauv microplastics teeb meem.
Vim nws muaj peev xwm decompose, nws feem ntau yog siv los ua cov khoom ntim rau biodegradable hnab yas, straws, khob, phaj, thiab tableware.
Degradation mechanism ntawm PLA
PLA ua rau tsis muaj roj ntsha tsis zoo los ntawm peb lub tshuab:
Hydrolysis: Cov ester pawg hauv cov saw tseem ceeb tau tawg, ua rau txo qis hauv molecular hnyav.
Thermal decomposition: ib tug complex tshwm sim uas tshwm sim nyob rau hauv lub tsim ntawm sib txawv tebchaw, xws li sib zog molecules, linear thiab cyclic oligomers nrog txawv molecular luj, thiab lactide.
Photodegradation: Ultraviolet hluav taws xob tuaj yeem ua rau degradation. Qhov no yog qhov tseem ceeb tshaj plaws uas nthuav tawm polylactic acid rau lub hnub ci hauv cov yas, ntim ntim, thiab daim ntawv thov zaj duab xis.
Cov tshuaj tiv thaiv hydrolysis yog:
-COO- + H 2 O → -COOH + -OH
Tus nqi degradation qeeb heev ntawm ambient kub. Ib txoj kev tshawb fawb xyoo 2017 tau pom tias PLA tsis muaj kev poob zoo hauv ib xyoos hauv dej hiav txwv ntawm 25 ° C (77 ° F), tab sis txoj kev tshawb no tsis ntsuas qhov decomposition lossis dej nqus ntawm cov saw hlau polymer.
Dab tsi yog thaj chaw thov ntawm PLA?
1. Cov khoom siv
PLA yog siv rau hauv ntau yam khoom siv, xws li cov khoom siv pov tseg, cov hnab ntim khoom hauv tsev loj, cov khoom siv hauv chav ua noj, nrog rau cov laptops thiab cov khoom siv tes.
2. Kev ua liaj ua teb
PLA yog siv rau hauv daim ntawv fiber ntau rau ib kab nuv ntses fiber ntau thiab nets rau cov nroj tsuag thiab nroj tsuag. Siv rau sandbags, paj lauj kaub, khi hlua, thiab hlua.
3. Kev kho mob
PLA tuaj yeem degraded rau hauv tsis muaj teeb meem lactic acid, ua rau nws tsim nyog siv los ua cov cuab yeej kho mob hauv daim ntawv ntawm cov thauj tog rau nkoj, ntsia hlau, phaj, pins, rods, thiab nets.
Plaub qhov xwm txheej feem ntau ua tau scrapping
1. Recycling:
Nws tuaj yeem yog chemical recycling lossis mechanical recycling. Hauv Belgium, Galaxy tau tshaj tawm thawj cov nroj tsuag rau kev rov ua dua tshiab ntawm PLA (Loopla). Tsis zoo li cov khoom siv rov ua dua tshiab, pov tseg yuav muaj ntau yam kuab paug. Polylactic acid tuaj yeem raug tshuaj zoo li monomers los ntawm thermal polymerization lossis hydrolysis. Tom qab ua kom huv si, cov monomers tuaj yeem siv los tsim PLA raw khoom yam tsis tau poob lawv cov khoom qub.
2. Composting:
PLA tuaj yeem ua rau biodegraded nyob rau hauv industrial composting tej yam kev mob, ua ntej los ntawm tshuaj hydrolysis, ces los ntawm microbial digestion, thiab thaum kawg degraded. Nyob rau hauv kev lag luam composting tej yam kev mob (58 ° C (136 ° F)), PLA tuaj yeem ib nrab (kwv yees ib nrab) decompose rau hauv dej thiab carbon dioxide nyob rau hauv 60 hnub, nrog rau qhov seem decomposing qeeb qeeb tom qab ntawd, nyob ntawm qhov crystallinity ntawm cov khoom. Nyob rau hauv ib puag ncig yam tsis muaj qhov tsim nyog, decomposition yuav qeeb heev, zoo ib yam li cov yas tsis muaj roj ntsha, uas yuav tsis ua kom tiav rau ntau pua lossis ntau txhiab xyoo.
3. Kub:
PLA tuaj yeem raug hlawv yam tsis muaj cov tshuaj chlorine uas muaj cov tshuaj lossis cov hlau hnyav, vim nws tsuas muaj cov pa roj carbon, oxygen, thiab hydrogen atoms. Hlawv scrapped PLA yuav tsim 19.5 MJ / kg (8368 btu / lb) ntawm lub zog yam tsis muaj qhov seem seem. Qhov txiaj ntsig no, nrog rau lwm qhov kev tshawb pom, qhia tias kev siv hluav taws xob yog ib txoj hauv kev zoo rau kev kho cov khib nyiab polylactic acid.
4. Pem hauv ntej:
Txawm hais tias PLA tuaj yeem nkag mus rau hauv qhov chaw pov tseg, nws yog qhov kev xaiv zoo tshaj plaws rau ib puag ncig vim tias cov khoom degrades maj mam ntawm qhov kub thiab txias, feem ntau maj mam li lwm cov yas tsis degradable.
Post lub sij hawm: Nov-20-2024