Qhov Tseem Ceeb Qhov Sib Txawv - Roj Hmab vs Yas
Roj hmab thiab yas yog ob qho tib si ua los ntawm cov khoom siv polymerized txawm tias muaj qhov sib txawv ntawm lawv lub cev thiab tshuaj lom neeg. Qhov sib txawv tseem ceeb ntawm Roj Hmab thiab Plastics yog tias Roj Hmab yog cov khoom lag luam polymerized ntawm isoprene whereas Yas yog ua los ntawm ntau cov hluavtaws thiab semi-synthetic organic polymer tebchaw. Ntau yam ntawm cov khoom yog tsim los ntawm cov roj hmab thiab yas nyob ntawm lawv cov yam ntxwv xwm.
Rubber yog dab tsi?
Roj Hmab yog ib yam khoom ntuj tsim, feem ntau yog sau los ntawm cov latex tau los ntawm tsob ntoo roj hmab, Hevea brasiliensis uas yog haiv neeg rau South America. Txawm li cas los xij, tam sim no, ntau hom ntoo roj hmab tau siv los sau cov latex, thiab South Asia yog suav tias yog cov neeg tsim khoom loj. Cov latex yog nplaum heev thiab muaj kuab heev thiab tau sau rau hauv cov hlab ntsha los ntawm txoj kev hu ua 'tapping'. Tom qab ntawd, cov latex sau tau raug xa mus rau kev ua lag luam. Ntawm no, cov roj hmab tau ua tiav rau hauv cov roj hmab qib siab lossis cov ntawv qib roj hmab.
Tshuaj, roj hmab yog ua los ntawm cov polymer ntawm cov organic compound hu ua 'isoprene,' uas yog tsib-carbon tsim nrog qhov hnyav molecular siab kawg vim cov txheej txheem ntawm polymerization. Cov roj hmab ntuj feem ntau yog 'vulcanized', qhov twg nws yog rhuab nrog sulfur txhawm rau txhim kho kev tiv thaiv thiab elasticity. Qhov no tau qhia los ntawm Charles Goodyear hauv xyoo 1839. Cov qib siab ntawm elasticity yog cov khoom tshwj xeeb ntawm cov roj hmab thiab cov kev siv feem ntau ntawm Roj Hmab yog; hoses, siv, floorings, dampeners, mem hluav erasers, log tsheb, khoom ua si, hnab looj tes, bands, thiab lwm yam.
YPlastic yog dab tsi?
Lo lus 'yas' yog los ntawm Greek lo lus 'plastikos' uas txhais tau tias "muaj peev xwm ua tau pwm". Cov yas yog tsim los ntawm ntau yam khoom siv hluavtaws thiab semi-synthetic polymer thiab tau siv dav hauv kev tsim khoom ntawm cov khoom thiab cov txheej txheem. Feem ntau, cov yas tsis tuaj yeem deform yam tsis muaj kev tawg thiab tsis tuaj yeem ua rau dej. Vim lawv qhov zoo tshaj plaws, cov yas tuaj yeem yooj yim molded rau hauv ntau yam duab.
Plastics tuaj yeem muab faib ua pawg raws li kev faib tawm sib txawv. Nyob ntawm cov qauv tshuaj thiab cov saw hlau sab, lawv tuaj yeem muab faib ua acrylics, polyesters, polyurethanes, silicones, thiab halogenated plastics. Lawv tuaj yeem muab faib ua ntau pawg nyob ntawm cov txheej txheem ntawm kev sib txuas. Plastics kuj poob rau hauv ob pawg tseem ceeb raws li lawv txoj kev kam rau siab thiab tus cwj pwm nyob rau hauv qhov kub thiab txias. Ob hom yog thermoplastics thiab thermosetting polymers. Thaum cov thermoplastics tau rhuab, lawv tau txais kev hloov pauv tshuaj thiab tuaj yeem ua pwm dua thiab rov ua dua thaum cov thermosets yaj thiab ua cov duab irreversibly. Thawj cov yas uas yog raws li cov khoom siv hluavtaws ua tiav yog Bakelite. Txog niaj hnub no, feem ntau cov yas yog tsim los ntawm petrochemicals. Txawm li cas los xij, vim muaj kev txhawj xeeb ntawm ib puag ncig, cov khoom siv txuas ntxiv dua tshiab xws li cellulose thiab starch yog siv los tsim bioplastics. Cov yas tau tuaj yeem hloov tau ntau yam khoom siv xws li; ntoo, pob zeb, tawv, iav, hlau, thiab lwm yam.
Qhov txawv ntawm Roj Hmab thiab yas yog dab tsi?
txhais cov roj hmab thiab yas
Roj Hmab: Roj hmab yog cov khoom lag luam polymerized ntawm isoprene
Plastics: Yas yog ua los ntawm ntau cov hluavtaws thiab semi-synthetic organic polymer tebchaw.
yam ntxwv ntawm roj hmab thiab yas
Properties
Roj Hmab: Roj Hmab yog ib yam khoom uas muaj elasticity heev thiab tuaj yeem ua kom tawv thiab tiv taus ntau dua ntawm vulcanization.
Plastic: Yas yog cov khoom siv uas tuaj yeem ua rau cov duab sib txawv vim lawv qhov zoo nkauj thiab tawv thiab dej resistant.
Nature
Rubber: Txawm hais tias cov roj hmab hluavtaws muaj, feem ntau ntawm cov roj hmab siv niaj hnub no muaj lub hauv paus chiv keeb
Plastics: Cov yas yog tsim los ntawm petrochemicals thiab muaj cov khoom siv hluavtaws.
Image Courtesy: "Plastic hlaws 1". Daim ntawv tso cai raws li (CC BY 2.5) ntawm Wikimedia Commons "Rubber bands - Xim - Studio duab 2011" los ntawm Bill Ebbesen - Tus kheej ua haujlwm (CC BY-SA 3.0) ntawm Wikimedia Commons
