Taw qhia
Polylactic acid (PLA), raws li biodegradable yas, tau siv dav hauv kev ntim khoom pov tseg hauv xyoo tas los no. Muab los ntawm cov khoom siv txuas ntxiv dua tshiab xws li pob kws hmoov txhuv nplej siab thiab qab zib bagasse, nws pom zoo biocompatibility thiab biodegradability, decomposing rau carbon dioxide thiab dej nyob rau hauv ob peb lub hlis nyob rau hauv industrial composting tej yam kev mob. Txawm li cas los xij, qis - qhov kub thiab txias ua haujlwm yog qhov kev txwv tseem ceeb rau cov ntawv thov PLA. Nws cov iav hloov pauv kub (Tg) feem ntau yog 55-65℃(tus nqi ib puag ncig 60℃). Hauv qab no qhov kub thiab txias, cov saw hlau molecular txav tau qis zuj zus, thiab cov khoom yuav nyuaj dua thiab nkig, tshwj xeeb tshaj yog nyob ze Tg, cuam tshuam rau nws qhov kev ua haujlwm qis.
Kev tshawb fawb tam sim no ntawm PLA qis- qhov kub thiab txias ua haujlwm feem ntau yog tsom rau kev hloov kho cov khoom siv thiab kev ntsuas theoretical. Cov ntaub ntawv qhia tau hais tias PLA ntshiab yog qhov ua rau embrittlement ntawm qhov kub thiab txias, nrog rau qhov txo qis hauv cov khoom siv kho tshuab. Hauv qab -60 degree, khoov lub zog thiab cuam tshuam lub zog poob qis, thiab qis dua -80 degree, lub zog dabtsi yog khoov txawm mus txog xoom, thaum lub elastic modulus txo qis. Txawm li cas los xij, cov ntaub ntawv xeem tshwj xeeb rau PLA pov tseg zoo tib yamyas ntshiab khobNyob rau hauv feem ntau siv kub tsawg (-20 degree) tseem tsis muaj. Txoj kev tshawb no ua qhov kev sim thiab tshuaj xyuas txog qhov no.
I. Cov yam ntxwv ntawm cov khoom thiab cov qauv kuaj
1.1 Cov yam ntxwv tseem ceeb ntawm cov khoom siv PLA
PLA yog ib nrab -crystalline polymer nrog cov qauv molecular tshwj xeeb thiab lub cev muaj zog. Raws li cov ntaub ntawv, poly-L-lactic acid muaj crystallinity ntawm kwv yees li 37%, Tg ntawm kwv yees li 65 degree, melting point ntawm 180 degree, tensile modulus ntawm 3-4 GPa, thiab khoov modulus ntawm 4-5 GPa. Cov yam ntxwv no txiav txim siab nws qhov kev ua haujlwm kub qis: nyob rau hauv chav tsev kub, nws yog nyob rau hauv lub khob iav, nrog lub melting point ntawm 150-160 degree, tab sis lub sij hawm ntev siv kub yuav tsum tsis txhob ntau tshaj 80 degree, txwv tsis pub nws yog feem ntau softening thiab degradation; ntawm qhov kub thiab txias, molecular saw txav yog txwv, nthuav tawm cov brittleness tseem ceeb, ua kom tsis taus thiab yooj yim tawg hauv qab 0 degree.
1.2 Specifications thiab Yam ntxwv ntawm Standard Disposable PLA yas ntshiab khob
Kev tshawb fawb kev lag luam qhia tau hais tias cov kev qhia tshwj xeeb ntawm tus qauv pov tseg PLAyas ntshiab khobyog raws li nram no:
| Peev xwm (oz / ml) | Sab saum toj Dia (mm) | Hauv qab Dia (mm) | Qhov siab (mm) | Qhov hnyav (g) | Siv |
|---|---|---|---|---|---|
| 5 oz (150 ml) | 74 | 45 | 69 | 4.8 | Cov dej txias |
| 6 ooj (180 ml) | 74 | 45 | 80 | 4.8 | Cov dej txias |
| 8 ooj (240 ml) | 78 | 45 | 86 | 5.2 | Cov dej txias |
| 12oz (360ml) | 89 | 57 | 108 | 8.5-9.3 | Cov dej txias |
| 16oz (480ml) | 89 | 57 | - | 10 | Cov dej txias |
Txoj kev tshawb no tau xaiv ib qho uas muaj 12oz (360ml) PLA pob tshab khob ua cov qauv kuaj. Nws hnyav 8.5-9.3g, yog tsim los ntawm kev txhaj tshuaj molding, thiab muaj cov phab ntsa nyias, raws li tus nqi - txo thiab txuag cov khoom tsim cov yam ntxwv ntawm cov khob yas pov tseg.
1.3 Kev sib piv nrog cov khoom siv yas qub
| Hom khoom | Qhov kub thiab txias | Tsawg-Cov yam ntxwv ua haujlwm kub | Tensile zog (MPa) | Elongation ntawm Break (%) | Flexural Modulus (GPa) |
|---|---|---|---|---|---|
| PLA | 45-50 degree | Brittle ntawm qhov kub thiab txias | 48-145 | 2.5-100 | 3.7-3.8 |
| PET | -40℃rau 60-70 degree | Ua nkig ntawm qhov kub thiab txias, Tg≈70 degree | 57 | - | - |
| PP | -40℃rau 100 degree | Khaws zoo toughness ntawm qhov kub thiab txias | 41-100 | 3.0-80 | - |
| CPET | -40℃rau 220 degree | Kev ua haujlwm siab thiab qis -kub zoo heev | - | - | - |
Raws li tuaj yeem pom los ntawm lub rooj, qhov kub tsis kam ntawm PLA yog qhov qis dua li cov khoom siv yas: txawm hais tias PET kuj ua rau qhov kub thiab txias, nws qhov kev ua tau zoo kuj zoo dua ntawm -20℃; PP muaj qhov dav tshaj qhov kub thiab txias, nrog kev ua haujlwm ruaj khov ntawm -40℃txog 100 degree; CPET muaj qhov zoo tshaj plaws kev ua haujlwm siab thiab qis qis. Hais txog cov khoom siv kho tshuab, PLA muaj ntau lub zog tensile, tab sis nws qhov elongation ntawm kev tawg yog qis dua li ntawm PP, qhia tias tsis muaj zog txaus.
II. Test Method Design
2.1 Cov Qauv Ntsuas Cov Qauv Ntsuas
Txoj kev tshawb no nruj me ntsis raws li cov qauv thoob ntiaj teb, feem ntau xa mus:
- ASTM D746-20 "Standard Test Method for Brittleness Temperature of Plastics and Elastomers by Impact": Qhia ib txoj hauv kev los txiav txim siab qhov kub thiab txias ntawm cov yas nyob rau hauv tej yam kev mob tshwj xeeb, txhais qhov kub ntawm 50% ntawm cov qauv yuav ua tsis tau.
- TS EN ISO 974: 2000 "Plastics - Kev txiav txim siab ntawm qhov cuam tshuam brittleness kub": Rau cov yas uas tsis nruj ntawm chav tsev kub, cov txheej txheem txheeb cais tau siv los ntsuas qhov kub ntawm qhov tawg.
- ASTM D618 "Standard Practice for Conditioning Plastics for Testing": Qhia meej txog cov txheej txheem txias thiab cov xwm txheej ntawm cov yas ua ntej kev sim, ua kom ntseeg tau thiab sib piv ntawm cov txiaj ntsig.
-
2.2 Sample Pretreatment thiab Environmental Conditioning
Raws li ASTM D618 tus qauv, cov qauv kuaj yuav tsum tau kho tus qauv ua ntej qis - ntsuas kub:
- Qauv ntxuav:Ntxuav cov qauv saum npoo nrog cov tshuaj ntxuav me me thiab dej deionized kom tshem tawm cov roj stains, plua plav, thiab lwm yam kab mob. Tom qab ntxuav, qhuav qhov chaw nrog ib daim ntaub huv, mos kom ntseeg tau tias nws qhuav thiab huv.
- Kev kho mob:Muab cov qauv tso rau hauv qhov chaw sim ntsuas qhov ntsuas kub ntawm 23 ± 2℃thiab cov av noo ntawm 50 ± 5% tsawg kawg yog 48 teev kom ntseeg tau tias cov qauv mus txog qhov chaw pib ruaj khov.
- Kev ntsuas pib:Tom qab pretreatment, ntsuas qhov loj me xws li txoj kab uas hla ntawm lub khob qhib, txoj kab uas hla ntawm lub khob hauv qab, qhov siab, thiab phab ntsa thickness siv cov cuab yeej precision xws li micrometers thiab calipers, thiab sau cov ntaub ntawv thawj zaug.
2.3 Cov khoom siv kuaj thiab kev tswj ib puag ncig
Cov cuab yeej tseem ceeb siv hauv txoj kev tshawb no yog raws li hauv qab no:
- Tsawg-Lub Freezer Kub: Tus kws tshaj lij -20℃qis-kub cia lub freezer nrog kev tswj qhov kub thiab txias ntawm ± 0.5℃thiab uniformity ntawm ± 2.0℃.
- Temperature Monitoring System: PT100 kub sensors (qhov tseeb ± 0.1 degree) yog siv los saib xyuas cov qauv ntsuas kub hauv lub sijhawm.
- Cov cuab yeej ntsuas: Siab-cov micrometers qhov tseeb (qhov tseeb 0.01mm), vernier calipers (qhov tseeb 0.02mm), thiab qhov sib npaug hluav taws xob (qhov tseeb 0.01g).
- Optical Inspection Equipment: High- daws teeb meem digital microscope thiab lub teeb dawb interferometer rau kev soj ntsuam qhov tawg.
2.4 Test Parameter Chaw
Raws li cov qauv kev xav tau thiab cov kev xav tau tiag tiag ntawm daim ntawv thov, cov ntsuas ntsuas tau teeb tsa raws li hauv qab no:
| Kev kuaj mob | Kev teeb tsa Parameter | Lus hais |
|---|---|---|
| Kev ntsuas kub | -20 ± 1 degree | Lub hom phiaj txias txias |
| Short-Tsev Sij Hawm Xeem | 1h,2 ua | Ob lub sij hawm cov ntsiab lus |
| Ntev - Lub Sij Hawm Xeem | 24 teev, 48 teev, 72 teev | Peb lub sij hawm cov ntsiab lus |
| Qauv Quantity | 10 cov qauv piv txwv rau ib pab pawg | Ua kom muaj kev ntseeg tau zoo |
| Temperature Equilibrium Sijhawm | Tsawg kawg yog 1 teev | Xyuas kom tus qauv ntsuas kub stability |
2.5 Cov txheej txheem xeem tsim
Qhov kev xeem yog ua nyob rau hauv batch, nrog 10 parallel qauv kuaj ntawm txhua lub sij hawm taw tes. Cov kauj ruam tshwj xeeb yog raws li nram no:
Kev Npaj Qauv: Cov qauv ua ntej- cov qauv kho tau muab faib ua 5 pawg (10 tus qauv rau ib pawg). Ib pawg ua haujlwm pab pawg tswj hwm (tsis yog khov), thiab plaub pawg ntxiv yog siv rau 1-teev, 2-teev, 24-teev, thiab 72-teev kev ntsuas khov, feem.
Kev Ntsuas Kev Ua Haujlwm Thaum Ntxov: Cov pab pawg tswj hwm tau kuaj pom qhov pom, ntsuas qhov ntev, ntsuas qhov hnyav, thiab ntsuas qhov nyuaj los tsim cov ntaub ntawv hauv paus.
Freezing Test: Cov qauv kuaj tau muab tso rau hauv lub freezer -20 degree. Tom qab tos tsawg kawg yog 1 teev kom ntseeg tau tias qhov kub thiab txias sib npaug, cov qauv raug tshem tawm ntawm lub sijhawm teem tseg, thiab lawv qhov kev ua tau zoo raug soj ntsuam tam sim ntawd kom tsis txhob muaj qhov kub thiab txias cuam tshuam rau cov txiaj ntsig.
Kev ntsuas kev ua tau zoo: Qhov no suav nrog kev tshuaj xyuas qhov muag (kev tawg, deformation), ntsuas qhov ntev (hloov qhov loj me), ntsuas qhov hnyav, ntsuas qhov tawv, thiab kuaj pom tawg (microscopic soj ntsuam ntawm qhov tawg ntev, qhov tob, thiab kev faib tawm).
Kev Ntsuam Xyuas Cov Ntaub Ntawv: Kev txheeb xyuas txheeb cais yog ua los ntawm cov ntaub ntawv xeem, suav cov ntsuas xws li qhov nruab nrab thiab tus qauv sib txawv los ntsuas qhov kev ntseeg tau ntawm cov txiaj ntsig.
III. Kev Ntsuam Xyuas Kev Ua Haujlwm
3.1 Brittleness Kev Ntsuas Cov Qauv
3.1.1 Crack Length Classification Standards
| Crack Level | Ntev Ntau | Qhov hnyav | Kev Txiav Txim Siab |
|---|---|---|---|
| Me Crack | Tsawg dua los yog sib npaug li 2 hli | Me ntsis | Tsis cuam tshuam rau kev ua haujlwm |
| Luv Crack | 2-5 hli | Nruab nrab | Muaj feem xyuam rau kev zoo nkauj tab sis tsis ua haujlwm |
| Nruab nrab Crack | 5-10 hli | Mob hnyav | Muaj feem xyuam rau kev ua haujlwm |
| Ntev Crack | >10 hli | Hnyav heev | Ua rau kev ua tsis tiav |
3.1.2 Kev ntsuam xyuas qhov ntom ntom ntom ntom
Crack ceev=Tag nrho qhov tawg ntev / Sample deg cheeb tsam. Cracking branching ntom thiab faib cov yam ntxwv kuj tau sau tseg thiab soj ntsuam raws li GB / T13298-2015 tus qauv.
3.1.3 Kev ntsuas kub ntawm brittleness
Raws li ASTM D746 thiab ISO 974 tus qauv, lub brittleness kub yog hais txog qhov kub thiab txias ntawm 50% ntawm cov qauv ua rau tawg tawg nyob rau hauv tej yam kev mob. Txawm hais tias txoj kev tshawb fawb no tsom mus rau -20 degree, kev sim ntxiv tau ua los txiav txim siab qhov kub thiab txias ntawm PLA cov khob dej ntshiab..
3.2 Kev Ntsuas Kev Ntsuas Cov Qauv
3.2.1 Linear Dimension Hloov Tus Nqi
Kev hloov pauv tus nqi (%)=(Dimension tom qab kho - Initial dimension) / Initial dimension × 100%. Cov kev ntsuas tseem ceeb suav nrog kev hloov pauv ntawm lub khob lub qhov taub, lub khob hauv qab txoj kab uas hla, qhov siab, thiab phab ntsa thickness.
3.2.2 Cov duab Deformation Coefficient
Warpage: Ntsuas qhov flatness sib txawv ntawm lub khob qhov ncauj thiab hauv qab. Qhov siab tshaj plaws tso cai sib txawv yog 0.5 hli, nrog rau kev siv dav hlau flatness yuam kev ntawm<0.05 mm.
Roundness deviation: Ntsuas qhov hloov pauv ntawm lub khob ntawm qhov siab sib txawv uas siv lub ntsuas ntsuas qhov sib npaug.
Perpendicularity sib txawv: Ntsuas qhov kev hloov ntawm perpendicularity ntawm lub khob axis thiab hauv qab nto.
3.2.3 Volume Change Rate
Volume hloov pauv tus nqi (%)=(Ntau tom qab kev kho mob - Lub ntim pib) / Initial ntim × 100%. Volume yog ntsuas los ntawm cov dej filling txoj kev, siv lub precision ntsuas lub tog raj kheej los ntsuas qhov ntim ntawm cov dej ntim..
3.2.4 Phab ntsa Thickness Uniformity Hloov
Ntsuas phab ntsa tuab ntawm lub khob qhov ncauj, nruab nrab ntawm lub khob lub cev, thiab hauv qab (4 cov lus qhia ntawm txhua qhov chaw) siv lub micrometer. Xam cov qauv sib txawv thiab coefficient ntawm kev sib txawv los ntsuas qhov sib txawv ntawm qhov sib txawv.
3.3 Cov qhab nia ntsuam xyuas kev ua tau zoo
| Qib | Qib Brittleness | Qib deformation | Kev pom zoo siv |
|---|---|---|---|
| Zoo heev | Tsis muaj kab nrib pleb | Deformation<1% | Haum rau kev siv ib txwm |
| Zoo | Me ntsis tawg (<2mm) | Deformation 1-3% | Siv ceev faj |
| Ncaj ncees | Cov kab nrib pleb luv (2-5mm) | Deformation 3-5% | Tsis pom zoo rau kev siv sijhawm ntev - |
| pluag | Medium-long cracks (>5 hli) | Deformation >5% | Tsis tsim nyog siv |
| Neeg pluag heev | Kev tawg hnyav | Kev deformation hnyav | Ua tsis tiav |
IV. Kev Xeem thiab Kev Ntsuam Xyuas
4.1 Luv luv-Lub Sijhawm Tsis Muaj Kev Xeem Xeem (1-2 teev)
Kev sim luv luv -lub sij hawm kuaj pom tau tias PLA cov khob yas ntshiab pom qhov tseem ceeb qis- qhov kub thiab txias ntawm -20℃. Cov ntaub ntawv tshwj xeeb yog raws li nram no:
| Lub Sijhawm Xeem | Qauv nab npawb | Cracking mob | Qhov siab tshaj plaws Crack Length (mm) | Qhov nruab nrab Crack ceev (mm / cm²) | Khob Qhov Ncauj Hloov (%) | Qhov siab hloov (%) |
|---|---|---|---|---|---|---|
| 1 hnu | 1-5 | Me ntsis tawg | 1.2-1.6 | 0.15-0.20 | -0.6 - 0.9 | -0.3 - 0.6 |
| 1-teev nruab nrab | - | Me ntsis tawg | 1.4±0.1 | 0.17±0.02 | -0.76±0.1 | -0.46±0.1 |
| 2 teev | 6-10 | Cov kab nrib pleb luv / me ntsis tawg | 1.8-2.4 | 0.22-0.30 | -1.0 rau -1.3 | -0.6 - 0.9 |
| 2-teev nruab nrab | - | Cov kab nrib pleb luv luv | 2.2±0.2 | 0.28±0.03 | -1.16±0.1 | -0.76±0.1 |
Tom qab 1 teev ntawm khov, me me tawg tshwm nyob rau hauv tag nrho cov qauv. Cov kab nrib pleb no feem ntau tau muab faib rau ntawm ntug ntawm lub khob, hauv qhov chaw muaj kev ntxhov siab ntawm lub khob lub cev, thiab ntawm qhov sib txuas ntawm lub hauv qab thiab sab phab ntsa, nrog rau kev faib tawm. Tom qab 2 teev ntawm kev khov, cov kab nrib pleb zuj zus, nrog cov kab nrib pleb luv tshwm hauv 4 ntawm 5 cov qauv. Qhov nruab nrab tawg qhov ntev thiab qhov ntom ntom tau nce ntxiv, qhia tias lub sijhawm khov khov ntev ntev ua rau cov pob txha tawg.
Hais txog deformation, tom qab 1 teev, qhov nruab nrab txoj kab uas hla ntawm lub khob qhib tau cog lus los ntawm -0.76±0.1%, thiab qhov siab cog lus los ntawm -0.46±0.1%; Tom qab 2 teev, qhov contraction tseem ceeb dua, nrog rau lub khob qhib txoj kab uas hla cog lus los ntawm -1.16 ± 0.1% thiab qhov siab los ntawm -0.76 ± 0.1%. Lub deformation yog raws li qhov kub thiab txias thermal shrinkage yam ntxwv ntawm PLA.
4.2 Ntev-Cov Kev Xeem Ua Si Lub Sij Hawm (24 teev lossis ntau dua)
Kev sim ntev - tau pom tias muaj kev puas tsuaj ntxiv ntawm PLA cov khob yas ntshiab, nrog rau kev puas tsuaj loj heev. Cov ntaub ntawv yog raws li nram no:
| Lub Sijhawm Xeem | Qauv nab npawb | Cov xwm txheej tawg | Qhov siab tshaj plaws Crack Length (mm) | Qhov nruab nrab Crack ceev (mm / cm²) | Khob Qhov Ncauj Hloov (%) | Qhov siab hloov (%) | Qhov hnyav hloov (g) |
|---|---|---|---|---|---|---|---|
| 24 teev | 11-15 | Nruab nrab / Ntev Cracks | 6.5-12.5 | 0.79-1.52 | -2.1 rau -2.5 | -1.6 rau -2.0 | -0.2 rau -0.3 |
| 48 hnu | 16-20 | Ntev Cracking / Loj Cracking | 14.6-25.2 | 1.78-3.04 | -2.9 rau 3.3 | -2.3 rau -2.7 | -0.3 - 0.5 |
| 72h ua | 21-25 | Cracking hnyav | 28.7-32.5 | 3.52-3.98 | -3.5 - 3.8 | -2.9 rau -3.2 | -0.5-0.6 |
4.3 Kev ntsuas kub thiab txias txias ntsuas
Lub sij hawm ntsuas kub sib npaug: Nws yuav siv li 30-40 feeb rau cov qauv kom txias los ntawm chav tsev kub (23 degree) txog -20 degree, thiab tsawg kawg yog 1 teev kom ncav cuag qhov kub thiab txias sib npaug, uas cuam tshuam rau cov qauv phab ntsa thickness, ntim, thiab lub peev xwm txias ntawm lub freezer.
Qhov kub ntawm qhov sib txawv: Hauv -20℃ib puag ncig, qhov kub sib txawv ntawm qhov sib txawv ntawm cov qauv yog nyob rau hauv ± 0.5 degree, thiab qhov kub ntawm lub khob qhov ncauj, lub cev, thiab hauv qab yog zoo ib yam, ua tau raws li qhov yuav tsum tau ua.
Thermal shrinkage yam ntxwv: Thaum lub khob PLA txias los ntawm chav tsev kub mus rau -20 degree, tus linear shrinkage tus nqi yog kwv yees li 0.3-0.5%. Qhov no shrinkage tsim kev ntxhov siab nyob rau hauv lub khob phab ntsa, uas yog ib qho tseem ceeb ua rau tawg tsim.
4.4 Kev sib piv nrog cov khoom siv yas
Txhawm rau kom paub meej qhov tsis txaus ntawm PLA cov khob yas ntshiab ntawm qhov kub thiab txias, lawv tau sim thiab muab piv nrog PET thiab PP yas ntshiab khob ntawm -20 degree. Cov txiaj ntsig yog raws li nram no:
| Hom khoom | Lub Sijhawm Xeem | Cracking mob | Qhov siab tshaj plaws Crack Length (mm) | Qhov nruab nrab Crack ceev (mm / cm²) | Khob Qhov Ncauj Hloov (%) |
|---|---|---|---|---|---|
| PLA | 2 teev | Cov kab nrib pleb luv luv | 2.2±0.2 | 0.28±0.03 | -1.16±0.1 |
| PET | 2 teev | Tsis muaj kab nrib pleb | 0 | 0 | -0.3±0.05 |
| PP | 2 teev | Tsis muaj kab nrib pleb | 0 | 0 | -0.2±0.03 |
Nws tuaj yeem pom tias qhov qis- qhov kub thiab txias ua haujlwm ntawm PET thiab PP yog qhov zoo dua li ntawm PLA: PET tsis muaj qhov tawg tom qab 2 teev ntawm qhov khov, thiab tsuas yog me me tawg tom qab 24 teev; PP tsis pom muaj kab nrib pleb thoob plaws hauv qhov kev sim, thiab nws qhov loj me me kuj yog qhov tsawg tshaj plaws. Qhov kev ua tau zoo sib txawv no tshwm sim los ntawm cov yam ntxwv ntawm cov khoom siv-PET muaj Tg ntawm kwv yees li 70 degree, thiab PP muaj Tg ntawm kwv yees li -10℃txog 0 degree, tuav lub zog ntawm -20℃; thaum PLA muaj Tg ntawm kwv yees li 60 degree, deb tshaj qhov ntsuas kub, nthuav tawm cov iav nkig.
4.5 Failure Mechanism Analysis
Raws li kev soj ntsuam microscopic, qhov ua tsis tiav ntawm PLAyas ntshiab khobntawm -20℃stems los ntawm kev sib xyaw ntawm ntau yam:
Tsawg-kub pob txha tawg: Ntawm -20 degree, kev txav ntawm PLA molecular chains raug txwv, ua rau tsis muaj zog, ua rau lawv muaj kev cuam tshuam rau cov pob txha tawg nyob rau sab hauv lossis sab nraud.
Thermal stress concentration: PLA muaj cov coefficient tsawg ntawm thermal expansion, ua rau thermal stress thaum txias. Cov kab nrib pleb pib thiab nthuav tawm hauv thaj chaw muaj kev ntxhov siab xws li lub khob ntug, lub cev, thiab kev sib koom ua ke ntawm hauv qab thiab phab ntsa;
Kev hloov pauv crystallinity: Lub sijhawm ntev ntawm qhov kub qis tuaj yeem ua rau txias crystallization hauv PLA, ntxiv rau cov khoom siv brittleness.
Cov txiaj ntsig kev ntxhov siab: Thaum qhov kub qis, qhov kev ntxhov siab ntawm PLA txo qis, ua rau nws nyuaj rau kev ntxhov siab sab hauv kom tso tawm, ua kom nrawm nrawm nrawm.
V. Kev sib tham thiab cov lus pom zoo
5.1 Daim ntawv thov tseem ceeb ntawm cov txiaj ntsig kev xeem
Cov kev ntsuam xyuas qhia tau hais tias ib qho yooj yim pov tseg pob tshab PLA yas ntshiab khob muaj kev txwv tseem ceeb ntawm -20℃: pom cov kab nrib pleb tshwm tom qab luv luv -lub sij hawm (1-}2 teev) khov, thiab ntev (24 teev lossis ntau dua) khov ua rau cov txheej txheem tawg. Qhov no txhais tau hais tias PLA yas ntshiab khob tsis haum rau lub sijhawm ntev cia ntawm -20 degree. Yog tias tsim nyog siv qhov kub thiab txias, nws raug nquahu kom ua qhov tseem ceeb ntawm cov khoom siv PET lossis PP; Yog tias yuav tsum tau siv PLA, kev ntsuas xws li nce phab ntsa tuab thiab ntxiv lub tes tsho tiv thaiv yuav tsum tau coj los txo kev puas tsuaj.
5.2 Yam tseem ceeb cuam tshuam rau cov txiaj ntsig kev xeem
Cov khoom tseem ceeb: Tg, qhov hnyav molecular faib, crystallinity, thiab cov ntsiab lus plasticizer ntawm PLA tag nrho cuam tshuam rau nws qhov kev ua haujlwm kub tsawg. Ntxiv cov yas yas xws li dioctyl adipate (DOA) thiab dibutyl sebacate (DBS) tuaj yeem txhim kho qhov tawv.
Cov qauv tsim qauv: Cov phab ntsa tuab thiab tsim ntawm qhov chaw muaj kev ntxhov siab ntawm lub khob cuam tshuam rau kev tawg. Ua kom cov phab ntsa tuab tuaj yeem txhim kho kev ua haujlwm, tab sis nws yuav ua rau cov nqi nce ntxiv.
Ib puag ncig thiab txheej txheem txheej txheem: Tus nqi khov thiab qhov kub thiab txias tuaj yeem ua rau cov khoom laus dua; cov txheej txheem tsim khoom, xws li kev txhaj tshuaj molding tsis thiab qhov ntsuas cua txias, cuam tshuam rau thawj qhov zoo ntawm cov khoom.
Kev hloov khoom siv: Txo Tg ntawm PLA los ntawm copolymerization / kev sib xyaw, ntxiv qis -cov yas yas kub, thiab tswj cov crystallinity nrog nucleating agents;
Kev ua kom zoo ntawm cov qauv: Thicken qhov tseem ceeb xws li lub khob ntug thiab hauv qab, ua kom zoo dua qhov tsim kom txo tau kev ntxhov siab, thiab txais yuav PLA / PE cov qauv sib xyaw.
Kev siv thiab cov qauv: Zam kom tsis txhob ntev - lub sij hawm cia ntawm PLA yas ntshiab khob ntawm -20 degree, tswj tus nqi ntawm qhov kub thiab txias hloov; txhawb kev tsim PLA kev ua haujlwm ntawm qhov kub thiab txias thiab cov txheej txheem kev siv.
5.3 Cov lus qhia txog kev txhim kho
Kev hloov khoom siv:Txo Tg ntawm PLA los ntawm copolymerization / blending, ntxiv qis -cov plasticizers kub, thiab tswj crystallinity nrog nucleating agents;
Structural Optimization:Thicken qhov tseem ceeb xws li lub khob ntug thiab hauv qab, thiab txhim kho qhov tsim kom txo tau kev ntxhov siab.
Kev siv thiab cov qauv:Tsis txhob ntev - lub sij hawm cia ntawm PLA yas ntshiab khob ntawm -20℃, thiab tswj tus nqi ntawm kub hloov.
5.4 Kev Tshawb Fawb Kev Txwv thiab Outlook
- Txoj kev tshawb no tsuas yog sim 12oz PLA yas ntshiab khob ntawm ib qho kub ntawm -20℃thiab nyob rau hauv 72 teev, thiab tsis npog lwm yam specifications, kub, thiab av noo yam. Cov kev tshawb fawb yav tom ntej yuav tsum tau nthuav dav qhov kev sim, txhim kho qis -kub hloov pauv hloov PLA cov ntaub ntawv, txhim kho cov kev ntsuam xyuas, thiab txhawb kev siv PLA kom muaj nuj nqis hauv cov ntim qis.
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VI. Cov ntsiab lus
Txoj kev tshawb no tau soj ntsuam xyuas qhov khov khov ntawm cov khoom siv pov tseg zoo tib yam PLA yas ntshiab khob ntawm -20℃los ntawm kev ntsuas tus qauv, nrog rau cov kev tshawb pom tseem ceeb hauv qab no:
Brittle Fracture Performance: Short-lub sij hawm khov (1-2 teev) ua rau me ntsis tawg tawg, thaum lub sij hawm ntev khov (72 teev) ua rau qhov nruab nrab tawg ntev ntawm 30.5 hli, ua rau ua tiav cov txheej txheem tsis ua haujlwm;
Kev ua tau zoo deformation: Kev khov ua rau lub khob ntim yas kom qis, nrog qhov siab tshaj plaws shrinkage ntawm -3.7% hauv khob ntug kab thiab -3.1% hauv qhov siab; deformation intensified lub sij hawm;
Kev sib piv ntawm cov khoom: Qhov qis- qhov kub thiab txias ntawm PLA yog qhov qis dua ntawm PET thiab PP, uas tswj kev ncaj ncees zoo thaum lub sijhawm sim;
Kev Ua Haujlwm Tsis Ua Haujlwm: Tsawg-kub brittleness, thermal stress concentration, hloov crystallinity, thiab kev ntxhov siab so ua ke ua rau PLA tsis ua haujlwm;
Cov lus pom zoo siv: Ordinary pob tshab PLA yas ntshiab khob tsis haum rau ntev - siv sijhawm ntawm -20℃; luv- siv sij hawm yuav tsum tau ceev faj; muab qhov tseem ceeb ntawm cov khoom siv uas tsis tshua muaj kub hloov tau xws li PET thiab PP.
