1、Living Polymerization 1 Introduction 1.1 Definitionchain polymerization without chain transfer and termination, but with chain initiation and propagation only.elementary reaction:I R*R* + M I-M* (initial active species)P* + M P* 1.2 Characteristics 1) MW vs conversion curve straight line through the
2、 original point,i i+1,2) the relationship between and the quantities of initiator and monomer consumedwhere f = no. of chain initiated by a molecule of initiator,3) molecular weight distribution (MWD)case 1 Ri RpMWD: Poisson distributionnumber distribution function,weight distribution functionwhere
3、j= no. of monomeric unit per a macromoleculex= kinetic chain length = j-1 thereforei.e. MWD is function of MW of polymer formed case 2 Ri RpMWD becomes broader or distribution index higher 4) kinetics,1.3 Experimental criteria 1) continue to polymerize during adding monomer further 2) linear curve o
4、f vs conversion through original point 3) constant no. of macromolecule independent of conversion 4) narrower MWD 5) MW may be calculated or controlled stoichiometry 6) block copolymer may be produced by subsequent addition of monomer 7) the end of macromolecule may be functionalized2 Living anionic
5、 polymerization,2.1 Anionic polymerizationA+B- + M MB-A+ BM-A+ monomer: electron-withdrawing group (AN)- conjugation (St) initiator: alkali metal (Li, Na, K)alkyl metal (RLi.) kinetic features: rapid initiationslow propagationno termination 2.2 Brief review1936, K. Ziegler, butadiene - Na, living po
6、lymer1943, Flory, EO - RONa - butanol (chain transfer agent),(nucleophilic reagent),no feature of living anionic polymerization 1956, Szwarc, St - naphthalene - Na - THFtypical living anionic polymerization,A,B,C,D,10 mL St,50 mL THF + 10 mL St,sodium naphthalene dissolved in 50 mL THF,greenish,cher
7、ry-reddish,milestone,5 secadd D50 sec (0.5 g/mL) D (isoprene) dissolved in toluenecould not be precipitated by isooctane,mechanism+ Na -Na+ greenishinitiation CH2=CH,.,.,.,+ CH-CH2 CH-CH2 -Na+ cherry-reddish,.,.,Na+- CH-CH2-CH2 -CH -Na+,propagation (n+m) CH2=CH,Na+- CH-CH2 ( CH-CH2 )(CH2-CH ) CH2 -C
8、H -Na+,n m,cherry-reddish color remains for several days or weeks killing technology:terminated by reagents to introduce functional groups, CH2CHCH2CH-Na+ + H2O CH2CHCH2CH2 + NaOH,+ CH3OH CH2CHCH2CH2 + NaOCH3,+ CO2 CH2CHCH2CHCOO-Na+,+ O2 CH2CHCH2CHOO-Na+,telechelic polymer / macromonomer (102 104),2
9、.3 Living anionic polymerization of polar monomerM: methyl methacrylate, vinyl methyl ketone, acrylonitrileI: nucleophilic reagent (R-Li+.) anionic polymerization takes place. living ? side reactions: (MMA),1) addition of CO to initiator,CH2=C-C=O,CH3,OCH3,+ R-Li+,CH2=C-C-OLi,CH3,OCH3,+ -,R,CH2=C-C=
10、O + LiOCH3,CH3,R,less active,2) metallization, CH2-C:-Li+,CH3,C=O,OCH3,+ CH2=C,CH3,C=O,OCH3, CH2-C C-C=CH2 + LiOCH3,CH3,C=O,OCH3,CH3,O,3) cyclization, CH2-C-,CH3,C=O,OCH3,CH2-C-Li+,CH3,C=O,OCH3, CH2-C C,CH2,O=C,CH3,CH3,CH2,C,COOCH3,COOCH3,+ LiOCH3,difficult to prepare living polymer for a long time
11、improvements: to depress the side reactionsless nucleophilic initiatorlower polymerization temperaturepolar solvent,MMA,CH3,steric effect: 1,1-diphenyl hexyl lithium 1,1-diphenyl 3-methylpentyl lithiumno side reaction 1) and 2), so as to become living anionic polymerization ex. Belgium, Liege Univer
12、sity, Teyssiet-butyl methacrylate - secbutyl Li - LiClsteric effect,CH3(CH2)4CLi,CH3CH2CHCH2CLi,CH3,3 Living cationic polymerization 3.1 Characteristics of cationic polymerization ex. BF3 + H2O H+(BF3OH)-CH3 CH3CH2=C + H+(BF3OH)- CH3-C+(BF3OH)- CH3 CH3long living ?termination by 1) chain transfer to
13、 monomerHMnM+(CR)- + M Mn+1 + HM+(CR)- 2) by self terminationHMnM+(CR)- Mn+1 + H+(CR)-,M,shorter life 3.2 Quasi-living cationic polymerization1979, Kennedy (Akron University)BCl3 / H2O / -MeSt(added dropwisely), 56 system results:conversionMWD index 2block copolymer when adding another monomer CH2-C
14、+BCl4 CH2-C-Cl + BCl3,-,CH3,CH3,low concentration of monomer, then add monomer slowly to depress chain transfer and termination 1980, Kennedy, “quasi-living cationic polymerization”compare with living cationic polymerization (Rt=0 and Rtr=0), Rt 0 and Rtr 0 when monomer is added slowly3.3 Living cat
15、ionic polymerizationIBVE / (I2/HI) / C6H14 / -15CH2=CH-O-i-C4H9 1976, Johnson and Young, IBVE / I2, add monomer, continue to polymerizeliving ?,1984, 东村延敏, IBVE/I2propagation speciesMW x N* new initiationMWD=1.41.6 (RiRp)Ri living?,dissociated undissociated (, Rp),M + I2 MI2 (charge-transfer complex
16、) fast MI2 + I2 I(M)I + I2 slowICH2CHORI3,+,-,co-ions effect (dissociation constant of HI that of I2),IBVE / (I2/HI=1/1) / C6H14 / -15I2initiator I2/HIHIx tMW xN* xMWD x,I2/HI I2 x t no induction period induction period straight line not straight line fast slow MWD 1.07 1.4 1.6 Mn x straight line st
17、raight linethrough original point not through original point N* x remain constant increase HI only, very slow rate (only 70% conversion after a month),initiation mechanism: I H CH2=CH + HI CH3-CH CH3-C II2OR OR OR gegen ionother system: 东村延敏, IBVE/diphenyl phosphate /zinc iodidePolymer Bulletin, 198
18、8, 20: 407-412 Kennedy J P, isobutylene/ter-ester acetate/BCl3Polymer Bulletin, 1986, 15: 317-323 东村延敏, IBVE/dioxane /AlEtCl2Macromolecules, 1989, 22: 1009-1013,I2,+ -,gegen ion C+ stability,nucleophilicity distance,4 Living coordination polymerization东京工业大学, Doi propylene / toluene / -78 V(acetylac
19、etonate)3 / AlEt2Cl soluble Ziegler-Natta initiatorCH3 H CH3 meta-positionC C O OO O CH3-C-CH2-C-CH3V1/3syndiotactic PP MWD = 1.19 0.05 most narrowNo. of macromolecular chain remains constant during 15 h polymerization,b,for V (acetylacetonate)3 / AlEtCl2 or Al2Et3Cl3No. of chain increases with conv
20、ersion because of the presence of chain transfer reaction a b c MWD t 1.56 1.98 1.19 0.05 1.53 2.07 Mn t not straight line straight line not straight line N t constant ,c a,Doi, mechanism: 1) propylene coordinates with activated V* 2) activated propylene inserts into V*Et-Al-Cl and then into V*CH-CH
21、2Et-Al-Cl EtCH3 Et AlR2Clabilityof formation of syndotactic PPAlEt2Cl Al(n-C3H7)2Cl Al(i-C4H9)2Cl AlEt2Br bimetallic structureNMR: second carbon inserts into -CH2-CHV*CH3 active centre connects with second carbon,N/Nr 0.05 Doi, highly active solution V(III) Ziegler-Natta initiatorN/Nr 1.02-methyl-1,
22、3-dibutanone V(III)CH3 ortho-position CH3 C H CH3C C H3C-C-C-C-HO O O H OV1/3RpN/Nr = 1.0,other systems 1) Teyssie (Lieye University, Belgium)Bd / bis(-allyl)(trifluoroactate)nickel 2) 东村延敏(大阪大学)ClC=C-R / MoCl5-n-Bu4Sn-EtOH5 Living free radical polymerization 5.1 Features of free radical polymerizat
23、ionslow initiation kd=10-4 10-6 S-1rapid propagation kp=102 104 L/molSvery fast termination kt=106 108 L/molS,problems for living free radical polymerization: 1) kt/kp 104, termination of free radical can not be avoided 2) slow initiation, new free radical will be produced after hours, and broader M
24、WDhow to preserve the activity of free radical?isolation to prevent or retard the encounter of two radicals? 5.2 Prevent the collision of free radical to bring about a “living” free radical polymerization 1) through “viscosity effect”UCCC, Kabanov, BMA+ZnCl2, -196 , -ray -196 , ESR, CH3-C-COOCH2-CH2
25、-CH2-CH3, constantCH3,*,complex, ZnCl2, ,-100, solid,-145 , ESR, CH2-C-COOCH2-CH2-CH2-CH3, constantCH3 -130 , free radical concentration , termination 2) through emulsion polymerization平井英史, s-PP peroxide powder, styrene,*,B,A,C,D,E,F,G,A: s-PP peroxide powder F and D: vacuum and N2 C: styrene + sur
26、factant + H2O E: after 30 min, turn 180, N2, separate the s-PP peroxide powder B: continue to polymerize G: styrene or methyl methacrylate,add MMA again, block copolymer (90%) add t-butyl styrene and styrene, triblock copolymer (University of Massachuseete, Brgdeli, Lenz and Oster),3) through plasma
27、 initiated polymerizationSimionescu, MMA, gas phase radical, concentrationMWMWD = 1.2 1.3,4) through temple polymerization T - T - T - T - T T - T - T - T - T M M M M M M -M -M -M -M T - T - T - T - T T - T - T - T - T M -M -M* M -M -M -M* 5) through precipitation polymerizationTFE PTFE50, =1000 sec
28、40, =2000 sec, R*=10-5 mol/L(10-2100, 10-710-9)5.3 Through iniferterinitiator-transfer-terminater,-N=N-C3 * + *C3 + N2 phenyl zao triphenyl methyl (PAT) ini terEt2N-C-S-S-C-NEt2 2Et2N-C-S*S S S tetra ethyl thiuram disulfide(TD) ini, fer, ter-N=N-S * + *S + N2 phenyl zao triophenyl ini fer 1956, Taka
29、yuki Otsu, St/TD/h 1981, Takayuki Otsu, mechanism different from that of initiated by AIBN results: 1) conversion, MW2) continue to polymerize during adding monomer further,h,3) block copolymer 3-C-C-3 2*C3 CH2-CHX-B CH2-CHX + B mechanism:AB A* + B*slow decomposition A* + CH2=CHX ACH2-CHX initiation
30、mMA ( CH2-CHX ) CH2-CHX propagationB*,*,*,*,m,A ( CH2-CHX ) CH2-CHXB rapid terminationA ( CH2-CHX ) CH2-CHX + B* redecompositionnM A ( CH2-CHX )( CH2-CHX ) CH2-CHX repropagationB* A ( CH2-CHX )( CH2-CHX ) CH2-CHXB reterminationpseudo-living polymerization, not typical living polymerizationstatistic
31、rule, broader MWD (56)5.4 Through radical complex,m,m,*,*,m,n,m,n,retard Rt by electron repulsion or steric effectA+ R*+ABC R*BC 1977, Lee Cr2+ + BPO sealed,R*,10, DMF initiator -78 , N2 30 1 h aging solution +MMA polymerization,results: 1)2) 3) AN, block copolymer real free radical polymerization i
32、f without aging or polymerization at 40 after agingaging and temperature why?,mechanism: chromous chromic at 30 , the coordinated free radical is unstablewithout aging, the coordinated free radical is not found,O O,.,.,.,.,MMA inserts the space between benzoyl radical and Cr3+ C6H5C * Cr3+ -OOCC6H5
33、+ MMAC6H5COOM* Cr3+ -OOCC6H5 CH3C6H5COO-CH2-C* Cr3+ -OOCC6H5H3CO-C-Oatom transfer radical polymerization (ATRP) 5.5 Through ATRP 5.5.1 Mechanism,O O,.,.,.,.,.,.,.,.,initiation:R-X + Mtn R* + Mtn+1-XM ki MR-M-X + Mtn R-M* + Mtn+1-X,propagation:R-Mn-X + Mtn R-Mn* + Mtn+1-XM kp MR-Mn+1-X + Mtn R-Mn-M*
34、+ Mtn+1-X 5.5.2 Initiator / catalyst system 1) R-I / AIBN or BPOSt, MA low level controlled free radical polymerization,2) AIBN / CuCl2-2,2-bispyridineSt controlled free radical polymerization 3) R-X(Cl, Br) / CuX-2,2-bispyridineSt, MA controlled free radical polymerization(bulk, solution, emulaion)
35、 5.5.3 Problems 1) large quantity of catalyst 2) can not controlled the polymerization of ethylene, vinyl acetate, vinyl chloride5.5.4 Application 1) polymer with narrow MWD,R-X / CuX / 2,2-bispyridine, St or MMA, MWD=1.1 1.2heterogeneous system living anionic or cationic polymer, MWD1.1, why?homoge
36、neous systemoil soluble group (n-butyl, i-butyl)homogeneous systemMWD=1.04(the smallest MWD of PS by free radical polymerization ) ex. Br / CuBr / =0.084 / 0.084 / 0.175mol/L H13C6 C6H13,N,N,R,N,N,St0 / Br0=100, T=110x% Mn MWD30 2900 1.0539 3700 1.0458 6400 1.0480 8800 1.05 2) polymer with functiona
37、l end group (macromonomer) i) R-XR-X + nM R X-NH2, -COOH50% functional end group ii) Z-R-X,ATRP,Z-R-X + nM Z XZ: -OH, -COOH, -R-CH=CH2100% functional end groupO ex. CH2=CH-O-C-CH2-Cl / CuCl / 2,2 -bpy, 130 , StO Cl CH2=CH-O-C-CH2 ( CH2-CH ) CH2-CH3) random or gradient copolymerliving anionic or cati
38、onic polymerizationblock copolymer random copolymer,ATRP,R- or R+ attacks the monomer with higher activity only St, MMA block St- + MMA MMA- + Strandomliving free radical polymerizationrandom copolymer gradient copolymerideal gradient copolymertactic gradient copolymerstatistical gradient copolymert
39、apered copolymer,i) rArB or rBrA A + B + initiators tapered copolymer ii) rA rB stepwisecontinuous ex. CH2BrCOOC2H5 / CuBr / 2,2 -bpy, 90 , MA/StMA 1.5 mmol/min ,4) block copolymerSBS i) macromonomer method Z X + Z -X ex. PS-PMA-PS ii) stepwise methodX X X ex. PMA-PS-PMA 5) star-type polymercorearm,
40、T ,No. of arm XCH2- -CH2X 2 Cl3C-CN 346,CH2X,CH2X,CH2X,CH2X,CH2X,CH2X,CH2X,CH2X,CH2X,CH2X,core,X,X,X,X,X,X,arm,functional end group,6) graft or comb (co)polymer i) macromonomerXii) macro-initiator+ nM7) hyperbranched polymer,X X X X,X,X,X,X,X,X,X,X,CH2X,CuX/bpy 100,CH2*,CH2X,CH2X,CH2-CH2-CH*,CH2X,CH2-CH2-CHX,CH2*,CH2-CH2-CH-CH2-CH*,CH2-CH2-CH*,CH2X,CH2X,CH2X,CH2-CH2-CH-CH2-CH-CH2-CH*,CH2-CH2-CH-CH2-CH*,CH2-CH2-CH*,CH2-CH2-CH*,CH2X,CH2X,CH2X,CH2X,
