ORGANIC CHEMSTRY II
ORGANIC CHEMSTRY II CHEM 332
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This 5 page Class Notes was uploaded by Columbus Torphy on Sunday September 27, 2015. The Class Notes belongs to CHEM 332 at Iowa State University taught by Staff in Fall. Since its upload, it has received 4 views. For similar materials see /class/214548/chem-332-iowa-state-university in Chemistry at Iowa State University.
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Date Created: 09/27/15
Polymers Unique features of polymers Chem 332 Chapter 31 Last updated 41301 Large MW or size strength high temperature resistance solvent resistance ame retardants Polymerization The joining together of monomers in order to make large molecules or polymers Chan Growth Polymers Produced by chain reactions Very fast reactions Require initiators Individual steps initiation propagation and termination All monomers are Vinyl 7 contain at least one CC Types a Free Radicals G I G Ill T nCH2 CH fCHz CHa Ini 7 usually peroxides 0 0 II N C 0 o C Types of monomers n CH2 CH2 gt fCHz CHza Ethylene Polyethylene II Q CHCH2 gt fCHz CH1 Styrene Polystyrene C1 C1 l gt I n CH2 CH fCHz CH5 Vinyl chloride PVC OCH3 CH30 O c0 C PK l n cc fCHz Clh H CH3 CH3 Methyl methacrylate Page 1 Chem 332 Chapter 31 Last updated 41301 CH3 CH3 I gt n CH2 CH CCH fCHz CHC CH31 Isoprene Polyisoprene Mechanism Initiation Peroxide A 2R39 hv R39CHgt H gt R CHz GH G G Propagation R CHz GH CHgt H gt R CHz CH CHz GH G G Termination Combination G G G G l R CHz CH CHz CH CH CHZ CH CH2 R E CF 3quot Cf R f CHz CHa cm CH CH CHzf CH CHz hR Disproportionation When G is a bulky group CF 3quot 1 3quot R f CHz CH ECHz CH CH C CH CHzLR l H G G CHG G R f CHz CH ECHz CH gHf CH CHza R b Cationic l YV CH gt Y CHz JFCH CHZ CH gt yf CHZ CH T1 G G G Initiation Propagation Many termination types 7 makes for poor products Y is a lewis acid G Page2 Chem 332 Chapter 31 Last updated 41301 Monomers 7 G needs to be electron donating CH 3 CH2C CH2 C CH3 OR Isobutene Vinyl ether c Anionic G E A E Nu39 CHz CH gt Nu CHz CH CHz oH gt NquHrCHa G Initiation Propagation Nu 7 eg Butyl lithium Monomers 7 b group needs to be electron withdrawing O H 3 C O CH2C PK Q CH CH2 CC CEN H Anionic monomers cannot be used for cationic chain polymerizations Cationic monomers cannot be used for anionic chain polymerizations Both cationic and anionic monomers can be used for free radical chain polymerizations Copolymers Two or more types of monomers Allows for some control on the properties of the products Types Random AABABABBAABABBBAA Alternating ABABABABABABABABA Block AAAAAAAAABBBBBBBB Graft AAAAAAAAAAAAAAAA l B B B B B B B Examples 1 StyreneAcrylonitrile 7 Random 7 e g Samsonite luggage 2 25Styrene75Butadiene 7 Random SBR 3 Butadiene Styrene 7 Graft 7 eg computer casing 4 20Vinyl chloride80Vinylidine chloride 7 Random Suran 5 EthyleneMethyl methacrylate 7 Random 6 IsobutyleneIsopropene 7 Random 7 Butyl rubber Step growth polymers No free radical or ionic initiation species Typically involve more than one functional group Page3 Chem 332 Chapter 31 Last updated 41301 Typically grow in both directions a a 21 21 b b gt a AB b gt b BA AB BA a V b b Examples 1 Polyamides Kevlar 7 bullet proof vests NH NH WM 2 2 1 c1 c1 H H O O C I II C II N N C C II NomeX 7 ame retardant O NH NH Ck C f 1 C1 C1 H H I 0 0 H H N N C GC n Nylon 0 0 f CH24 C HzN CHz5 NH2 C1 C1 H l ll ll N CH25 N C CH24 C Page 4 Chem 332 Chapter 31 Last updated 41301 2 Polycarbonates 0 CH3 II I O C O H0 OH l CH3 0 CH3 H I CO 0 H0 CH3 II 3 Polyethers FQEQF woC CM 1 CH3 W Q PAEK ICH3 C l CH3 n 4 Polyurathanes diisocyanate diol The unit in between the isocyanates can be benzenes or CHz s HO CH2n OH OCN NCO l CH3 0 CHZquotquot0 E T H O H H O n Urathan linkage Major39 cSEHESHEHquot3F 1 th x Page 5