Kev loj hlob thiab kev siv biodegradable polymer plastics, biodegradable plastics yog ib hom tshiab nrog kev ua haujlwm ntawm degradation ntawm cov ntaub ntawv polymer, hauv kev siv cov txheej txheem, nws yuav tsum ua nrog tib hom yas nrog rau kev noj qab haus huv thiab kev ua haujlwm ntawm daim ntawv thov, thiab Tom qab nws ua tiav kev ua haujlwm, cov khoom tuaj yeem degraded sai heev nyob rau hauv tej yam ntuj tso ib puag ncig tej yam kev mob ua ib qho yooj yim muab ib puag ncig fragments los yog crushed, thiab nrog rau lub sij hawm dhau mus degradation yuav nws thiaj li oxidation khoom (CO2 thiab dej), rov qab mus rau xwm.
Kev tsim kho thiab siv biodegradablecov khoom siv polymer, biodegradable plastics yog ib hom tshiab nrog kev ua haujlwm ntawm degradation ntawm cov ntaub ntawv polymer, hauv kev siv cov txheej txheem, nws yuav tsum ua nrog tib hom yas nrog rau kev noj qab haus huv thiab kev ua haujlwm ntawm daim ntawv thov, thiab tom qab nws ua tiav, cov khoom siv. tuaj yeem degraded sai heev nyob rau hauv tej yam ntuj tso tej yam kev mob los ua ib qho yooj yim muab ib puag ncig fragments los yog crushed, thiab nrog rau lub sij hawm dhau mus degradation ua nws thiaj li oxidation khoom (CO2 thiab dej), rov qab mus rau xwm.
Raws li ib puag ncig muaj kuab paug los ntawm cov pov tseg yas, nrog rau qhov kev thov ntawm kev tiv thaiv ib puag ncig thiab tib neeg kev xav tau, nws tseem ceeb heev los kawm cov ntaub ntawv polymer degradable.Nyob rau hauv ib lub sij hawm tshwj xeeb thiab nyob rau hauv tej yam kev mob ib puag ncig, cov qauv tshuaj ntawm biodegradable plastics yuav hloov.Raws li cov laj thawj rau kev hloov pauv hauv nws cov qauv tshuaj, biodegradable plastics tuaj yeem muab faib ua ob pawg: biodegradable plastics thiab photodegradable plastics.
1. Cov txheej txheem degradation ntawm cov yas degradable
Feem ntau hais lus, cov yas degradable yog hais txog ib hom yas uas tuaj yeem decomposed rau hauv me me molecules los ntawm kev ua ntawm cov kab mob hauv cov av lossis hnub ci hluav taws xob.Nws yuav tsum ua kom tau raws li qhov yuav tsum tau ua ntawm kev siv cov khoom thiab kev ua haujlwm yooj yim ntawm lub hauv paus. biodegradable zog.Qhov xwm txheej ntawm lub hnub ci ntawm cov ntaub ntawv polymer yog cov txiaj ntsig ntawm ultraviolet lub teeb nyob rau hauv tshav ntuj thiab oxygen hauv huab cua, yog li nws tseem hu ua photooxidation degradation.Siv polyolefin ua piv txwv los piav txog cov txheej txheem ntawm photooxidation degradation.Hauv cov ntsiab lus, photooxidation ua rau cov saw hlau tawg lossis kev sib txuas ntawm cov polymers, thiab qee cov pab pawg ua haujlwm oxygen, xws li carboxylic acids, peroxides, ketones thiab cawv, yog tsim nyob rau hauv cov txheej txheem no.Catalyst residues nyob rau hauv polymers thiab pib ntawm peroxide thiab carboxyl pawg qhia thaum lub sij hawm ua yog lub ntsiab ntawm degradation.
Nyob rau hauv qhov kev txiav txim ntawm cov kab mob (feem ntau yog fungi, kab mob los yog algae, thiab lwm yam), polymers tuaj yeem eroded los yog metabolized los ua kom muaj kev hloov hauv lawv cov qauv tshuaj thiab txo qhov hnyav molecular.Lub mechanism ntawm kev txiav txim feem ntau yuav muab faib ua ob yam:
(1) biophysical ua.Ntawd yog, tom qab kev yaig ntawm cov khoom yas los ntawm cov kab mob, cov kab mob lom, txhawb cov decomposition ntawm polymers, ionization los yog proton, qhov kev ua ntawm lub cev ntawm cov polymer ua rau cov neeg kho tshuab puas tsuaj, siab molecular hnyav ntawm cov polymer rau hauv oligomer fragments, thiaj li. ua tiav lub hom phiaj ntawm lub cev degradation.
(2) biochemical kev txiav txim - ncaj qha kev txiav txim ntawm enzymes.Qhov xwm txheej no yog tshwm sim los ntawm kev yaig ntawm cov enzymes secreted los ntawm cov kab mob los yog cov kab mob, uas ua rau kev sib cais los yog oxidative disintegration ntawm cov yas, thiab ua rau lub splitting los yog oxidative degradation ntawm insoluble polymers rau hauv dej-soluble fragments, tsim tshiab me me molecular compounds (CH4, CO2 thiab H2O) kom txog thaum kawg decomposition.
Feem ntau muaj ob lub tswv yim hais txog cov txheej txheem ntawm biodegradation ntawm cov ntaub ntawv polymer uas ua rau biodegradation.Lwm qhov yog kev txiav tawm ntawm qhov kawg ntawm cov saw hlau.Yog li ntawd, cov yam ntxwv ntawm cov ntaub ntawv, xws li muaj pes tsawg leeg, lub ntsiab thiab sab saw qauv, qhov loj ntawm cov pab pawg neeg kawg, thiab muaj los yog tsis muaj spatial steric resistance, yog cov tseem ceeb uas cuam tshuam rau lawv degradation kev ua tau zoo.Ntawm lawv, cov khoom tseem ceeb ntawm cov saw hlau muaj kev cuam tshuam ntau dua.Yog tias cov saw tseem ceeb ntawm cov polymer muaj cov ntawv cog lus uas yooj yim hydrolyzed, nws yuav yooj yim biodegraded.Qhov thib ob, yog tias cov pob txha hloov tau yooj yim, qhov degradation tus nqi yuav ceev heev, hos yog hais tias lub nraub qaum yog nruj thiab zoo, tus nqi degradation yuav qeeb.
Lub biodegradability ntawm cov ntaub ntawv polymer yog txo los ntawm branching thiab crosslinking.Piv txwv li, kev qhia txog cov pab pawg hydrophobic thaum kawg ntawm polylactic acid (PLA) molecular saw tuaj yeem txo qhov kev yaig ntawm qhov pib ntawm kev degradation.Qhov no yog vim hais tias nyob rau hauv thawj cov txheej txheem degradation, PLA qhov kev yaig feem ntau yog nyob ntawm cov qauv ntawm cov saw hlau molecular kawg, thiab qhov sib ntxiv ntawm pawg hydrophobic ua rau poob ntawm nws qhov kev yaig.Tsis tas li ntawd, qee cov kws tshawb fawb tau kawm txog cov qauv tshuaj ntawm cov polymers thiab cov txheeb ze molecular hnyav ntawm cov ntaub ntawv uas ua lub luag haujlwm tseem ceeb hauv lawv cov degradation.
2. Kev loj hlob ntawm biodegradable plastics
Txoj kev loj hlob ntawm biodegradable plastics yav tom ntej tuaj yeem ua raws li hauv qab no:
(1) biodegradable plastics tau npaj los ntawm kev kawm txog biodegradation mechanism ntawm degradable polymers, thiab block copolymerization ntawm biodegradable plastics nrog cov polymers uas twb muaj lawm, microbial polymers thiab natural polymers tau kawm thiab tsim.
(2) txhawm rau tshawb nrhiav cov kab mob uas tuaj yeem tsim cov khoom siv polymer, tshawb xyuas cov polymers tshiab, tshuaj xyuas lawv cov txheej txheem synthesis kom ntxaws, txhim kho lawv cov khoom tsim tau los ntawm cov txheej txheem uas twb muaj lawm thiab cov txheej txheem kev tsim cov noob caj noob ces, thiab kawm txog cov txheej txheem ntawm kev cog cov kab mob.
(3) xyuam xim rau kev tswj tus nqi degradation, txhim kho kev txhawb nqa degradation thiab stabilizers los txhim kho biodegradation kev ua tau zoo ntawm cov yas degradable, txo lawv cov nqi, thiab nthuav dav daim ntawv thov kev lag luam.
(4) Kev tshawb fawb thiab tsim kom muaj kev sib koom ua ke ntawm cov yas degradable, txhawb nqa thiab txhim kho txoj kev ntsuam xyuas ntawm biodegradation, thiab nkag siab ntxiv txog cov txheej txheem degradation.
Post lub sij hawm: Aug-13-2019