Butyl rubber-IIR

Butyl rubber (IIR), also called isobutylene-isoprene rubber, a synthetic rubber produced by copolymerizing isobutylene with small amounts of isoprene. .

Both isobutylene (C[CH3]2=CH2) and isoprene (CH2=C[CH3]-CH=CH2) are usually obtained by the thermal cracking of natural gas or of the lighter fractions of crude oil. At normal temperature and pressure isobutylene is a gas and isoprene is a volatile liquid. For processing into IIR, isobutylene, refrigerated to very low temperatures (approximately −100 °C [−150 °F]), is diluted with methyl chloride. Low concentrations (1.5 to 4.5 percent) of isoprene are added in the presence of aluminum chloride, which initiates the reaction in which the two compounds copolymerize (i.e., their single-unit molecules link together to form giant, multiple-unit molecules). The polymer repeating units have the following structures:

Because the base polymer, polyisobutylene, is stereoregular (i.e., its pendant groups are arranged in a regular order along the polymer chains) and because the chains crystallize rapidly on stretching, IIR containing only a small amount of isoprene is as strong as natural rubber. In addition, because the copolymer contains few unsaturated groups (represented by the carbon-carbon double bond located in each isoprene repeating unit), IIR is relatively resistant to oxidation—a process by which oxygen in the atmosphere reacts with the double bonds and breaks the polymer chains, thereby degrading the material. Butyl rubber also shows an unusually low rate of molecular motion well above the glass transition temperature (the temperature above which the molecules are no longer frozen in a rigid, glassy state). This lack of motion is reflected in the copolymer’s unusually low permeability to gases as well as in its outstanding resistance to attack by ozone.

 

28 comments

  1. What Is Amoxicillin Is Cephalexin Good Antibiotic For Pneumonia Cytotec For Miscarriage Dosage [url=http://mpphr.com]priligy en suisse[/url] Weight And Propecia Propecia Diccionario Propecia Without A Prescription Viagra [url=http://cialgeneri.com]generic cialis canada[/url] Canada Pharmacy No Script Online Progesterone Ups Worldwide Propecia Online Pharmacy Uk Priligy Experience Forum [url=http://viapill.com]viagra[/url] No Rx Fluoxetine Keflex And Utis Cialis And Bactrim [url=http://banzell.net]viagra online[/url] Clobetasol Want To Buy Medicine Cash Delivery Acheter Cialis Ligne How Long Does Zithromax Stay In The Body [url=http://cdeine.com]viagra[/url] Whisky Amoxicillin Correct Viagra Dosage Prix Alli Xenical

  2. Berichte Uber Levitra [url=http://gaprap.com]viagra[/url] Swollen Lymph Nodes Neck Keflex Acheter Viagra Femme Nolvadex Sans Ordonnance [url=http://ciali40mg.com]canadian cialis[/url] Levitra Otc Viagra Cialis Und Kamagra Erfahrungsbericht Online Drugstore Flagyl Pay By Money Order Seroquel [url=http://aquedan.com]how to find zoloft[/url] Liquid Clomid For Sale Sito Di Vendita Gravi Kamagra Cheapest And Fastest Delivery Of Cialis Ofloxacin Vs Ciprofloxacin Onlinepharmacy.Vom [url=http://viacheap.com]viagra[/url] Bacterial Infection Keflex Buy Valtrex Uk Amoxicillin With Breast Feeding [url=http://sildenafdosage.com]viagra online prescription[/url] Priligy Vendita Online Italia

  3. Can You Buy Ciprofloxacin 500 Mg Online Buy Amoxicillin Elixer Propecia Escuelas [url=http://levitab.com]cialis viagra levitra kaufen rezeptfrei[/url] Cialis Generika Aus Eu Cialis E Effetti Collaterali

  4. Que medicamentos venden sin receta? [url=https://antidepresivoses.wordpress.com/2019/03/05/comprar-lexapro-escitalopram-10-mg-20-mg-5-mg-online-barata/]Comprar Lexapro[/url] Consumo de antidepresivos en Paraguay. Como comprar Risnia (Risperidone) sin receta? Marcas de antidepresivos en en Espana [url=http://www.criandocuervos.com/]Cialis online[/url] Donde comprar sin receta medica Risnia (Risperidone)?. Risnia (Risperidone) cuanto cuesta? Marcas de antidepresivos en en Paraguay [url=https://medium.com/@sat1_59862/farmacias-online-comprar-medicamentos-baratos-412eb2857082]Farmacias online barata[/url] Que tomar para la depresion?.

    Risnia (Risperidone) generico en Ecuador
    Marcas de antidepresivos en en Colombia
    Los Antidepresivos en Ecuador
    Antidepresivos naturales Ecuador
    Risnia (Risperidone) precio Quatemala

  5. Comprar Wellbutrin (Bupropion) Generico Online Sin Receta [url=https://antidepresivoses.wordpress.com/2019/03/04/risperdal-risperidone-comprar-barato-sin-receta/]Risperdal sin receta[/url] Los antidepresivos Ecuador. Comprar Wellbutrin Bupropion 150 mg en linea [url=https://antidepresivoses.wordpress.com/2019/03/05/comprar-geodon-ziprasidone-40-mg-80-mg-20-mg-sin-receta/]Comprar Ziprasidone[/url] Los antidepresivos en Bolivia. Wellbutrin (Bupropion) cuanto tarda en hacer efecto? Wellbutrin (Bupropion) precio Mexico [url=https://antidepresivoses.wordpress.com/2019/03/05/comprar-remeron-mirtazapine-15-mg-30-mg-sin-receta/]Comprar Mirtazapine[/url] Comprar Wellbutrin (Bupropion) online barata .

    Wellbutrin (Bupropion) Chile precio
    Ventas de antidepresivos en Chile
    Precios de los antidepresivos en Chile
    Marcas de antidepresivos en en Espana
    Antidepresivos en Chile

  6. Cuanto cuesta el Zyprexa (Olanzapine) sin una receta? [url=https://antidepresivoses.wordpress.com/2019/03/05/comprar-tofranil-imipramine-25-mg-50-mg-75-mg-sin-receta/]Comprar Imipramine[/url] Ventas de antidepresivos en Espana. Comprar Zyprexa Olanzapine 5 mg, 7,5 mg, 10 mg, 20 mg online Antidepresivos marcas Costa Rica [url=https://antidepresivoses.wordpress.com/2019/03/05/cymbalta-duloxetine-20-mg-30-mg-40-mg-de-venta-libre-en-farmacias/]Duloxetine 20 mg venta libre[/url] Que pastillas sin receta para dormirse rapido?. Que pastillas sin receta para dormirse rapido? Zyprexa (Olanzapine) generico en Chile [url=https://antidepresivoses.wordpress.com/]Antidepresivos sin receta[/url] Zyprexa (Olanzapine) como funciona? .

    Zyprexa (Olanzapine) comprar en Costa Rica
    Zyprexa (Olanzapine) Argentina precio
    Marcas de antidepresivos en en Mexico
    Ventas de antidepresivos en Espana
    Consumo de antidepresivos en Colombia

  7. Cialis en vente libre [url=http://cialis20mg.hexat.com/index]Cialis[/url] au Canada. Pharmacie en ligne fiable [url=http://cialispourfemme.bravesites.com/]Cialis[/url]

  8. Achat medicaments livraison gratuite pharmacie en ligne

  9. India Cialis Sales Online [url=http://asacdz.com]cialis online[/url] Canadian Cialis Pharmacy Zithromax Antybiotyk Cheapest Anxiety Meds No Prescription

  10. [url=http://www.bojanas.info/sixtyone/forum/upload/member.php?u=871275]Coupon for Cialis[/url] Ordering Coupon for Cialis side effects penis size. [url=https://cialiscoupon.wordpress.com/price/]Cialis Coupon[/url] Generic drug for Cialis Coupon cost. Order Cialis Coupon side effects body building forum. [url=http://cialiscoupon.bravesites.com/cialiscoupon]Cialis Coupon[/url] Low dose Cialis Coupon side effects? [url=http://btc-f.org/forum/profile.php?id=165084]Cialis Coupon[/url]

  11. [url=http://theblissfoundationus.com/forums/users/bioram/]Cialis Coupon[/url] Reviews for ordering generic Coupon for Cialis from pharmacy. [url=https://medium.com/@cialiscoupon/free-cialis-coupon-new-2019-59f8eeb43676]Coupon for Cialis[/url] Order Cialis Coupon side effects percentage. Side effects of Cialis Coupon drug side effects. [url=https://cialis-coupon.jimdosite.com/]Cialis Coupon[/url] Information on the medication Cialis Coupon online canadian pharmacy reviews. [url=http://uniton.by/users/Bioflien]Coupon for Cialis[/url]

  12. [url=http://www.oryantiringciyiz.com/member.php?action=profile&uid=198]Cialis[/url] Order Cialis Coupon and alcohol dangerous. [url=п»їhttps://medium.com/@tadalafil/april-may-2019-cialis-coupons-9473945fcc37]Coupon for Cialis[/url] Best company to buy Cialis online reviews. Mail Order Cialis Coupon generic. [url=https://cialiscoupon.hatenablog.com/entry/2019/04/16/214830]Coupon for Cialis[/url] Online generic Coupon for Cialis without prescription reviews. [url=http://www.mama-krasnodara.ru/user/Eneldceddut/]Cialis Coupon[/url]

  13. [url=https://vw88yes.com/forum/profile.php?id=293803]Cialis[/url] How many people report Cialis Generic side effects? [url=п»їhttps://medium.com/@tadalafil/april-may-2019-cialis-coupons-9473945fcc37]Cialis Coupon[/url] Best place to buy generic Coupon for Cialis online reviews. How long do sexual side effects of Coupon for Cialis last? [url=https://medium.com/@cialiscoupon/april-may-2019-cialis-coupons-7e5a024c685b]Cialis Coupon[/url] Best place buy Cialis Coupon online reviews. [url=http://bongdapluz.com/bongdaso/profile.php?id=88813]Cialis Coupon[/url]

  14. Howdy! I could have sworn I’ve been to this website before but after looking at a few of the posts I realized it’s new to me. Anyways, I’m certainly pleased I stumbled upon it and I’ll be book-marking it and checking back frequently!

    https://twitter.com/cybertechnews3/status/1108122489375330309

  15. [url=http://uniton.by/users/Bioflien]Cialis Coupon[/url] Get free samples now Cialis reviews. [url=https://cia142.wixsite.com/cialis-coupon]Cialis Coupon[/url] Customer reviews of canadian Coupon for Cialis no prescription. Generic drug for Coupon for Cialis price. [url=https://medium.com/@tadalafil]Coupon for Cialis[/url] Best place buy Cialis Coupon online reviews. [url=http://ymygl.com.cn/bbs/home.php?mod=space&uid=106525]Coupon for Cialis[/url]

  16. For more information about Viagra and alcohol, you can see our blog post ‘Viagra & Alcohol’. can you buy viagra over the counter Except that he’s dressed in this athletic gear, you know, a jogging suit, one of those matching top and bottom get-ups with a zipper down the front.

  17. Pilule du desir pour femme Pharmacie en ligne. Assurance maladie pour l’Europe, Acheter Cialis 20 mg Paypal maladie

  18. Cialis pas cher en ligne Card Vital en France. Les services medicaux en France, Tadalafil 5mg sans ordonnance maladie

  19. This is how erection normally occurs in your body, and you will manage to maintain it with the help of healthy male Viagra. viagra online Pierce, Assistant Professor, Department of Military History, U.S.

  20. Acheter Cialis en ligne forum Assurance maladie pour l’Europe. Les services medicaux en France, Canadian pharmacy maladie

  21. Achat Tadalafil 5mg Canada Pharmacie en ligne. Les services medicaux en France, Cialis professionnel maladie

  22. Whats up this is kinda of off topic but I was wanting to know if blogs use WYSIWYG editors or if you have to manually code with HTML. I’m starting a blog soon but have no coding skills so I wanted to get advice from someone with experience. Any help would be enormously appreciated!

  23. If a drug kills, say, one person in 150,000, that side effect is unlikely to show up during pre-approval trials. viagra generic name As my doctor explained it was the constant stress but also 17 years of marriage that spread to my sex relationships with all my loved ones.

  24. This is the job description http://9taxi.in.net/ 9 taxi Ciaran’s step-mother also took to the family’s Facebook page ‘Missing Ciaran Sweeney’ to say: ‘As Ciaran’s step mother and on behalf of the family id like 2 thank u all 4 ur kind words xx Anyone wishing 2 leave flowers may do so on melbourne court xx’

  25. I’m sorry, I’m not interested http://xnxx.promo/ xnxxw A few years ago Unique Home Stays suffered a power supply failure. The next day, a Dell engineer visited its Cornwall headquarters and made the required fixes before the problems were a cost to the business.

  26. very best job http://xnxx.in.net/ xnxx tube The enrollment period for small business is 12 months, and officials said small businesses would be able to shop for coverage, fill out paper insurance applications or discuss their options with call center staff beginning next week.

  27. Pretty! This was a really wonderful post. Thank you for providing this information.

    https://twitter.com/katekdesigns/status/984992233328906240

  28. I believe this site contains some real excellent information for everyone : D.

    http://www.oprolevorter.com/

Leave a comment