Qee qhov nrov ntawm kev paub txog cov khoom siv roj hmab
Muaj ntau ntau yam khoom siv raw hauv cov khoom siv roj hmab, tab sis lawv txhua tus poob rau hauv ob pawg dav:
Cov roj hmab ntuj (cov kua txiv hmab txiv ntoo) thiab cov roj hmab hluavtaws (tsim nyob rau hauv cov chaw tsim tshuaj lom neeg lossis chaw soj nstuam).
Kev lag luam, cov roj hmab hluavtaws tseem ceeb tshaj plaws yog styrene butadiene (SBR), polyacrylic thiab polyvinyl acetate (PVA);
Lwm hom muaj xws li polyvinyl chloride (PVC), polychloroprene (feem ntau hu ua neoprene), thiab ntau hom polyurethane.
Thaum cov roj hmab ntuj thiab cov roj hmab hluavtaws zoo sib xws hauv qee qhov kev hwm, lawv tau tsim los ntawm cov txheej txheem sib txawv thiab muaj cov tshuaj sib txawv kiag li.
Kub kub sealing nplhaib
natural rubber
Cov roj hmab ntuj yog tsim los ntawm cov kua dej ntws tawm, hu ua latex uas oozes tawm ntawm qee cov nroj tsuag thaum koj txiav rau hauv lawv.
Piv txwv li dandelions, tsim latex; Yog hais tias koj snap tawm lawv stems, koj yuav pom latex dripping tawm lawv.
In theory, there is no reason why we can't make rubber by growing dandelions, although there are more than 200 kinds of plants in the world that can be used to produce latex, more than 99 percent of the natural rubber in the world is produced by a tree called Hevea brasiliensis Made of latex made from tree species.
Cov latex yog hais txog ib qho - dej thib peb, thiab ib qho - peb cov roj hmab, nyob rau hauv daim ntawv hu ua colloidal suspension. Ntuj roj hmab yog ib tug polymer ntawm isoprene (tseem hu ua 2-methyl-1,3-butadiene) thiab muaj cov tshuaj formula (C5H8)n.
Ntau yooj yim dua, nws muaj ntau txhiab tus C5H8 theem pib (isoprene monomers) xoob txuas rau daim ntawv ntev, tangled chains.
These molecular chains can be pulled apart fairly easily, but if you release them, they just snap back - that's what makes the rubber elastic.
synthetic rubber
Synthetic roj hmab yog refined siv petrochemicals hauv tshuaj nroj tsuag.
Thawj, thiab nto moo tshaj plaws, yog: Neoprene (lub npe lag luam rau polychloroprene), uas yog tsim los ntawm reacting acetylene thiab hydrochloric acid.
Another synthetic rubber: Emulsion Styrene Butadiene Rubber (E-SBR) is widely used in the manufacture of vehicle tires.
This article focuses on natural rubber.
Roj hmab shock pad
How is rubber made?
Kev tsim cov khoom siv roj hmab los ntawm cov roj hmab ntuj yuav tsum muaj ntau yam sib txawv.
1. First, latex must be collected from rubber trees using a traditional process called rubber tapping.
This involves making wide V-shaped cuts in the bark of the tree. As the latex drips out, it is collected in a cup.
2. Cov latex los ntawm ntau tsob ntoo yog tom qab ntawd lim, ntxuav thiab ua rau cov kua qaub ua rau cov khoom siv roj hmab coagulate (kaw ua ke).
Cov roj hmab ua rau hauv txoj kev no yog nias rau hauv cov ntawv tuab lossis cov ntawv nyias nyias thiab tom qab ntawd qhuav hauv kev npaj rau theem tom ntej ntawm kev tsim khoom.
Plus, when it gets cold, it tends to get cold, smelly, sticky, sticky.
Kev ua haujlwm ntxiv tom qab ntawd tig nws mus rau hauv cov khoom siv ntau yam.
3. A mechanical process first known as a "chewing machine" that uses mechanical rollers and pressure to "chew" raw rubber to make it softer, easier to handle, and stickier.
Tom qab cov roj hmab tau masticated, cov tshuaj ntxiv tau muab sib xyaw rau hauv kev txhim kho nws cov khoom (piv txwv li, ua kom nws hnav ntau dua- tiv taus).
4. Tom ntej no, cov roj hmab yog flattened los ntawm rollers (ib txoj kev hu ua calendering), los yog extruded los ntawm tshwj xeeb zoo li lub qhov los ua ib tug hollow raj (ib txoj kev hu ua extrusion).
5. Finally, the rubber is vulcanized (cooked): sulfur is added and the rubber is heated to about 140 degree (280 degree F) in an autoclave (an industrial pressure cooker).
shock absorbing cover
Roj hmab tuaj qhov twg?
Cov ntoo roj hmab Hevea brasiliensis, raws li nws lub npe qhia, keeb kwm tuaj ntawm Brazil, tab sis tau qhia rau cov tebchaws nyob rau sab hnub tuaj xws li Malaysia, Indonesia, Myanmar, Cambodia, Tuam Tshoj thiab Nyab Laj.
During World War II, when the military demand was huge, the supply of natural rubber to these countries was cut off, which accelerated the development of synthetic rubber, especially in Germany and the United States.
Today, most natural rubber still comes from the Far East, while Russia and its former Soviet states, France, Germany and the United States are the world's leading producers of synthetic rubber.
The world's largest single source of latex rubber is the Harbel Rubber Plantation near Monrovia, Liberia, established by the Firestone Tire Company in the 1920s and 1930s.
cav intake pipe
Roj hmab ua tau dab tsi?
The physical and chemical properties of a material determine its use. Even if you don't know anything about the real purpose of rubber, you can make some good guesses.
Piv txwv li, txhua tus paub tias roj hmab muaj zog, ncab, ruaj thiab tsis muaj dej, yog li nws yog qhov xav tias nws tuaj yeem siv rau hauv cov khaub ncaws tsis muaj dej.
There are many products made of rubber, but the most important use of rubber is in car tires; about half of the world's rubber ends up wound up on the wheels of cars, bicycles, and trucks!
Txij li thaum nws yog impermeable heev rau gases, lub log tsheb yuav nyob twj ywm inflated rau lub sij hawm ntev.
Roj hmab tuaj yeem ua tsis tau tsuas yog muag muag, tab sis kuj nyuaj, thiab nws yog cov khoom zoo uas ua rau muaj ntau yam uas nws tuaj yeem siv tau.
Mos thiab stretchy latex yog siv nyob rau hauv txhua yam ntawm erasers, balloons, tiv thaiv cov hnab looj tes, adhesives rau cov xim.
Cov roj hmab tawv tuaj yeem siv rau kev poob siab- nqus cov cushions thiab lub nkoj ua pa.
Vim tias cov roj hmab muaj zog, hloov tau, thiab tsis zoo thermal thiab hluav taws xob conductivity, nws kuj yog siv los ua ib lub cable.
Ntxiv rau qhov ntawd, nws muaj ntau yam kev siv: los ntawm lub siab lub ntsws mus rau cov dej tsis zoo rau lub qhov rooj ntxhua khaub ncaws, koj yuav pom nws hauv txhua daim ntawv thov!
Neoprene yog qhov zoo dua -paub txog txhua yam roj hmab, tab sis nws muaj cov ntawv thov ntau tshaj qhov uas tib neeg feem ntau paub txog, tsis yog nws feem ntau siv hauv kev kho mob, tab sis nws kuj tau siv dav hauv cov roj hmab vim nws yooj yim. thiab dej tsis kam. Cov khoom siv hauv tsev xws li lub ru tsev thiab hauv pem teb sealants.
Roj hmab Diaphragm
Thaum lub ntiaj teb muaj kev xav tau loj rau cov roj hmab tshiab, peb kuj tsim cov roj hmab pov tseg ntau, tshwj xeeb tshaj yog cov log tsheb pov tseg.
Raws li lub koom haum Rubber Manufacturers, ze li ntawm 270 lab cov khoom siv roj hmab tsheb log tsheb tau tsim nyob hauv Tebchaws Meskas hauv xyoo 2011 ib leeg, suav txog li ib -feem peb ntawm kev siv log tsheb thoob ntiaj teb.
While some of it is used to make floors like children's playgrounds, more than half of it is wasted (whether burned as fuel or buried in landfills).
Ntawm no tus editor ceeb toom txhua tus neeg tias txawm tias roj hmab zoo, ua tib zoo saib xyuas kev tiv thaiv ib puag ncig
Lub Cev Roj Hmab Seals
Keeb kwm luv luv ntawm Roj Hmab
1492: Long before Columbus discovered the Americas, Indians living in Central and South America had learned how to make waterproof clothing and shoes from the latex of the rubber tree. They called the rubber tree "cahuchu" (crying wood), which is why French rubber is still called natural rubber today (pronounced "cow-chew").
1731: Thaum lub sijhawm taug kev mus rau South America, Fabkis tus kws tshawb nrhiav Charles Marie de La Condamine xa cov qauv roj hmab rov qab mus rau Tebchaws Europe, ua rau muaj kev txaus siab rau kev tshawb fawb.
1770: The discoverer of oxygen, British scientist Joseph Priestley, discovers that he can use a rubber sheet to erase pencil marks on paper. In England, erasers are still widely known today as "rubber".
1791: Tus txiv neej Askiv Samuel Peal tsim ib txoj hauv kev ua cov ntaub tsis muaj dej los ntawm cov tshuaj roj hmab.
1818: Cov tub ntxhais kawm kho mob Scottish James Syme siv roj hmab-coated daim ntaub los ua cov tsho tiv nag.
1839: Tus neeg tsim khoom Asmeskas Charles Goodyear tau pom tias yuav ua li cas rau vulcanize roj hmab tom qab pov cov khoom (kho nrog leej faj) mus rau qhov cub kub.
1876: British explorer Sir Henry Wickham smuggled thousands of seeds from Brazil's rubber tree, Hevea brasiliensis, and returned to England.
The British planted the seeds at Kew Gardens outside London and exported them to various countries in Asia, establishing the giant plantations that now supply most of the world's rubber.
1877: Asmeskas cov chaw tsim khoom roj hmab Chapman Mitchell tsim thawj cov txheej txheem rau rov ua cov roj hmab.
1882: John Boyd Dunlop tau tsim lub log tsheb pneumatic (pneumatic) roj hmab, tom qab ntawd qhov kev thov rau roj hmab pib tawg.
1930: Ib pab neeg ntawm DuPont American chemists coj los ntawm Wallace Carothers tau tsim cov roj hmab revolutionary hluavtaws hu ua polychloroprene thiab muag nws li neoprene. (Tsis ntev tom qab, tib pab pawg tau tsim cov khoom siv ntau dua: nylon)
Automotive condenser foob