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Transcript of chemistry project
-an elastomer (a polymer that can regain its shape after being deformed)
-resistant to chemicals/weathering
-made mostly of Isoprene monomers. Hevea Brasiliensis (Rubber Tree) How are erasers made? Discovery / Science Channel's "How It's Made" Before erasers, people used rolled up pieces of white bread to erase graphite. The story is that in 1770, Edward Naime grabbed a piece of rubber instead of the bread on accident, and realized its capabilities! What IS rubber? Rubber is often defined as a solid substance that after vulcanization becomes elastic, including natural rubber (caoutchouc) and synthetic rubber. What does it cost to make rubber? The Chemistry of Erasers Rubber's composition Natural Rubber Sketches Rubber
Synthetic vs Natural In 1858, Hymen Lipman patented erasers on the end of pencils. It was later revoked because it combined 2 things instead of inventing a new thing Presentation by:
Claire Parkinson made from monomers of petroleum,coal, oil, natural gas, and acetylene made from latex inside Hevea Brasiliensis tree, or other shrubs/trees with latex resistant to chemicals/extreme temperatures the switch from natural to synthetic 1960's to 1990's Reasons
to prevent latex allergies in students
didn't have to depend on South East Asia where rubber trees grew
cheaper, and made rubber better suited for industrial use double bonds Vulcanization Charles Goodyear invented the process of vulcanization in the late 1830's Rubber is treated with sulphur and high temperatures durable
unaffected by temperature
good insulator Rubber without vulcanization Vulcanized Rubber Rubber molecule's sticky when warm
brittle when cold possible additives:
iron oxide (red color)
vegetable oil (softness), pumice (to make abrasive) also called caoutchouc April 15th is National Rubber Eraser Day! [CH2C(CH3)=CHCH2]n Allowed rubber to be widely used in different industries mainly polyvinyl chloride The United States was cut off from almost all of its sources of natural rubber in the Pacific during World War II, so it launched the synthetic rubber industry only moderate resistance to light, heat etc. can stand chipping, cutting or tearing has tack (can adhere to other materials) natural rubber crops only grow in tropical climates better resistance to abrasion, heat and aging. many types are flame-resistant (used as insulation for electrical devices) flexible at low temperatures resistant to grease and oil. common synthetic rubbers: ex) rubber for a car tire needs different properties then rubber for an eraser can be made with specific properties for specific uses changing the composition of rubber by adding different monomers easier to produce for some countries * BR (butadiene rubber)
* SBR (Styrene-butadiene rubber)
* IIR (Butyl rubber -- or halo-butyl rubber) Structural Formula Can rubber be dangerous? -"Rubber compounds generally do not pose a health hazard unless heated. Under normal conditions of processing and use, exposure to the chemical constituents in this product is unlikely. All ingredients are tightly bound in a polymeric matrix that has a negligible vapor pressure so there is a low potential for inhalation or ingestion of ingredients."-Gravitational Systems MATERIAL SAFETY DATA SHEET on Ethylene Propylene Diene Monomer (EPDM) Rubber 'Final'
-Latex Allergies Natural Rubber Synthetic Rubber Since most rubber is synthetic now,
the price of rubber fluctuates depending on the price of oil, not on the growth and trade of rubber trees. produces chemical links between the loosely coiled polymeric chains; elasticity occurs because the chains can be stretched and the crosslinks cause them to spring back when the stress is released Tire industry, conveyor belts, seals, technical rubber products like erasers Tires, conveyor belts, clutches, engine bearings, technical products of all types, erasers, drinking water seals Automotive hoses, tire inner liners, seals, membranes, rubberized fabrics, steam hoses, cable insulation soluble in a number of hydrocarbons, including benzene, toluene, gasoline, and lubricating oils Rubber got its name because it can RUB out mistakes! creates disulfide crosslinks so rubber molecule chains won't slide over eachother Isoprene:
88.2% Carbon, 11.8% Hydrogen
molar mass= 68.12 g/mol Chemical Reactions: The people Central and South America were the first to realize rubber's unique properties. Christopher Columbus watched them play a game called "Tlachtlic," a mix between basketball and football, with the goal of getting a rubber ball through a stone ring. Rubber trees require a hot, damp climate, they grow only in the "Rubber Belt," an equatorial zone that stretches around the world. When a tree is six or seven years old, an incision in the tree can be cut and latex is collected, This doesn't affect tree's health and the tree wound heals itself later. properties dictated by temperature always returns to original shape Approximately 70% of all rubber used is synthetic today. E Helmenstine, Anne Marie. "How Do Pencil Erasers Work?" About.com Chemistry. About.com, n.d. Web. 02 Dec. 2012. <http://chemistry.about.com/od/chemistryfaqs/f/eraser.htm>.
Galiano, Rich. "Scuba Diving - New Jersey & Long Island New York." Scuba Diving. Scuba Diving, 28 Apr. 2009. Web. 25 Nov. 2012. <http://njscuba.net/artifacts/matl_polymers.html>.
Gregorius, Roberto. "Eraser Composition and Function." Eraser Composition and Function. NEWTON Ask a Scientist, 15 Apr. 2005. Web. 25 Nov. 2012. <http://www.newton.dep.anl.gov/askasci/mats05/mats05011.htm>.
"How Products Are Made." How Eraser Is Made. Made How, n.d. Web. 02 Dec. 2012. <http://www.madehow.com/Volume-5/Eraser.html>.
"Isoprene." ChemSpider. RSC: Advancing Chemical Sciences, 21 May 2012. Web. 03 Dec. 2012. <http://www.chemspider.com/Chemical-Structure.6309.html>.
Kauffman, George B. "Chemistry Explained." Rubber. Chemistry Explained, n.d. Web. 02 Dec. 2012. <http://www.chemistryexplained.com/Ru-Sp/Rubber.html>.
Labbe, Michelle. "Properties of Natural & Synthetic Rubber." EHow. Demand Media, 24 Dec. 2010. Web. 03 Dec. 2012. <http://www.ehow.com/list_7686133_properties-natural-synthetic-rubber.html>.
McNeil, Anne J. "A String of Monomers: That's How Tires, Erasers, Shoe Soles Are Made." CCMR. Cornell Center for Materials Research, 4 Jan. 2006. Web. 02 Dec. 2012. <http://www.ccmr.cornell.edu/education/ask/index.html?quid=950>.
Ritter, Steve. "C&EN: WHAT'S THAT STUFF? - ERASERS." C&EN: WHAT'S THAT STUFF? - ERASERS. Chemical and Engineering News, 16 Dec. 2002. Web. 02 Dec. 2012. <http://pubs.acs.org/cen/whatstuff/stuff/8050erasers.html>.
"RMA: Rubber FAQs." RMA: Rubber FAQs. Rubber Manufacturers Association, n.d. Web. 03 Dec. 2012. <http://www.rma.org/about_rma/rubber_faqs/>.
"Rubber." FactMonster.com. Pearson Education, n.d. Web. 03 Dec. 2012. <http://www.factmonster.com/encyclopedia/science/rubber-synthetic-rubber.html>.
"Synthetic Rubber." Synthetic Rubber. German Insurance Association, n.d. Web. 03 Dec. 2012. <http://www.tis-gdv.de/tis_e/ware/kautschuk/synthesekautschuk/synthesekautschuk.htm>. How do pencil erasers work? Pencil erasers are made out of tiny globes of rubber loosely punched together.
The graphite fills up the eraser, then the eraser shaves off until it is a new clean surface to erase with. Altough I'm far from the point.. I don't make mistakes.. I fix yours... what am I? Pencils could be made with erasers on both ends, but that would be pointless. What did the pencil say to the eraser?
I'm feeling all write, my friend. Trivia:
What percent of rubber is synthetic today in the US?
What element is used in crosslinking during vulcanization?