Qhov sib txawv tseem ceeb ntawm cov roj hmab ntuj thiab cov roj hmab vulcanized yog cov roj hmab ntuj yog cov thermoplastic, hos cov roj hmab vulcanized yog cov thermoset.
Natural rubber yog cov khoom siv roj hmab uas peb tau txais los ntawm cov ntoo roj hmab. Cov latex nyoos tsis yog siv ntau vim nws muaj cov khoom tsis zoo. Txhawm rau txhim kho nws cov khoom, peb tuaj yeem vulcanize roj hmab siv sulfur lossis lwm txoj kev tsim nyog. Tom qab ntawd, peb hu nws "vulcanized roj hmab".
Natural Rubber yog dab tsi?
Natural rubber yog cov latex ntawm cov ntoo roj hmab uas muaj kev sib xyaw ntawm cov polymers. Cov latex nyoos yog nplaum thiab yog ib qho mis nyuj uas yog los ntawm kev txiav ntawm cov tawv ntoo ntawm cov ntoo roj hmab. Peb hu cov khoom sau los ntawm cov kua dej uas tau los ntawm cov qhov txhab ntawm cov tawv ntoo ua "tapping".
Natural roj hmab latex muaj cis-1, 4-polyisoprene polymer. Qhov hnyav molecular ntawm cov polymer no txawv ntawm 100,000 txog 1,000,000 D altons. Feem ntau, 5% ntawm qhov qhuav ntawm cov roj hmab latex yog lwm cov ntaub ntawv organic thiab inorganic; cov khoom siv organic muaj xws li cov proteins, fatty acids, resins, thiab lwm yam thaum cov ntaub ntawv inorganic suav nrog ntsev. Txawm li cas los xij, qee qhov lwm qhov chaw ntawm cov roj hmab muaj cov trans-1, 4-polyisoprene, uas yog cov qauv isomer ntawm cis-1, 4-polyisoprene.
Daim duab 01: Tapping
Raws li lawv cov khoom, cov roj hmab ntuj yog elastomer thiab cov khoom siv thermoplastic. Ntxiv mus, cov roj hmab nthuav tawm cov tshuaj lom neeg thiab lub cev muaj zog. Qee yam ntawm cov khoom no muaj raws li hauv qab no:
Properties of Rubber
- Hyperplastic xwm
- Txheej crystallization
- Susceptible to vulcanization
- Sensitive rau ozone tawg
- Dissolves hauv turpentine thiab naphtha
- Ammonia tuaj yeem tiv thaiv cov roj hmab los ntawm coagulation
- pib yaj ntawm 180 °C
Ntxiv mus, cov roj hmab uas tsis tau kho yog qhov tseem ceeb rau cov cement, rau cov ntaub ntawv insulating, kev sib txhuam daim kab xev, thiab lwm yam. Vim cov roj hmab ntuj tsis muaj ntau yam khoom tsim nyog, nws muaj tsawg daim ntawv thov ntau dua li cov roj hmab vulcanized.
Vulcanized Rubber yog dab tsi?
Vulcanized roj hmab yog cov khoom siv tom qab vulcanization ntawm cov roj hmab ntuj. Vulcanization yog ua los txhim kho cov khoom ntawm cov roj hmab ntuj; Yog li, nws muaj ntau yam khoom tsim nyog (nrog rau ntau daim ntawv thov). Vulcanization yog txheej txheem ntawm kev tsim cov crosslinks ntawm polymer chains. Yog li, qhov txheej txheem no hardens cov khoom siv roj hmab.
Daim duab 02: Tus neeg ua haujlwm tso lub log tsheb hauv pwm Ua ntej Vulcanization
Kev lig kev cai, peb xa mus rau kev kho cov roj hmab ntuj nrog sulfur li vulcanization. Tam sim no, muaj ntau txoj hauv kev rau lub hom phiaj no. Peb tuaj yeem hais tias vulcanization yog cov txheej txheem kho elastomers. Nws yog vim hais tias kev kho yog hais txog hardening ntawm cov ntaub ntawv los ntawm kev sib txuas sib txuas. Yog li, cov txheej txheem yuav pab tau kom rigidity thiab durability. Feem ntau, vulcanization yog irreversible.
Cov tshuaj siv los ntawm ntau txoj kev ntawm vulcanization yog raws li hauv qab no:
- Sulfur
- peroxide
- Metallic oxides
- Acetoxysilane
- Urethane crosslinkers
Txawm hais tias siv leej faj yog txoj kev siv ntau tshaj plaws, nws yog txheej txheem qeeb thiab yuav tsum muaj cov sulfur ntau. Ntxiv mus, nws yuav tsum tau kub thiab cua sov rau lub sij hawm ntev. Lub ntsiab tseem ceeb uas peb yuav tsum xav txog thaum lub sij hawm vulcanization yog lub sij hawm dhau mus ua ntej nws pib (scorch lub sij hawm), tus nqi ntawm vulcanization thiab qhov twg ntawm vulcanization.
Qhov txawv ntawm Ntuj Roj Hmab thiab Vulcanized Roj Hmab yog dab tsi?
Natural rubber yog cov latex ntawm tsob ntoo roj hmab uas muaj kev sib xyaw ntawm cov polymers, thaum cov roj hmab vulcanized yog cov khoom siv tom qab vulcanization ntawm cov roj hmab ntuj. Qhov sib txawv tseem ceeb ntawm cov roj hmab ntuj thiab cov roj hmab vulcanized yog nyob rau hauv lawv cov khoom siv kho tshuab. Qhov ntawd yog; Cov roj hmab ntuj yog cov thermoplastic, hos cov roj hmab vulcanized yog cov thermoset. Tsis tas li ntawd, cov roj hmab ntuj tshwm sim raws li cov kua mis colloid thiab yog tsim los ntawm cov ntoo roj hmab raws li nws cov latex hauv cov tawv ntoo. Vulcanized roj hmab yog cov khoom siv tawv tawv uas muaj cov kab sib txuas ntawm cov saw hlau polymer thiab yog tsim los ntawm vulcanization. Yog li, qhov no yog lwm qhov sib txawv ntawm cov roj hmab ntuj thiab cov roj hmab vulcanized.
Nyob hauv qab info-graphic ntawm qhov sib txawv ntawm cov roj hmab ntuj thiab cov roj hmab vulcanized qhia ntau qhov sib piv ib sab.
Summary – Ntuj Roj Hmab vs Vulcanized Rubber
Natural roj hmab yog ib yam khoom uas tshwm sim thaum vulcanized roj hmab yog cov khoom uas tsim tom qab vulcanization ntawm ntuj roj hmab. Qhov sib txawv tseem ceeb ntawm cov roj hmab ntuj thiab cov roj hmab vulcanized yog cov roj hmab ntuj yog cov thermoplastic whereas roj hmab vulcanized yog cov thermoset.
