jlu高分子材料reviewppt课件

1、高分子资料Review20191. Polymer Natural polymer: wool, wood, cotton, silk, cellulose, cheese, etc. Synthetic polymer: rubber, fiber, plastics, coating, adhesive, man-made leather. Differences between polymers and small molecules: molecular size, distribution, melting point, volatilizationClassification(1)

2、 Material PropertyThermoplastics, Thermosets (2) Polymerization MechanismAddition polymersCondensation polymers(3) Main-Chain StructureCarbon-carbonCarbon-oxygenCarbon-sulfurCarbon-nitrogenSilicon-oxygen(4) PerformanceIntelligent (smart) polymerOrganic nanomaterials Please explain the following conc

3、epts. Thermoplastics, Thermosets, Functional polymers, Addition polymers, Condensation polymersQuestions 2. Polymer structureLong-chain molecules composed of a large number of repeating units of identical structure (MW: 103 107). -repeating-unit1-x-repeating-unit2-y-repeating-unit3-z-Y=0, Z=0: PS, P

4、E, PP, PET. Y0, z=0: X Y Z 0: ABSMonomer, repeating unit, structural unit, nomenclature, abbreviation -CH2-CH2-n-CCababCCabab顺式反式CCabCCab顺式反式cdcd顺反异构Configuration构型aaCCaabCCaab不是顺反异构Trans-cis (Geometric) isomerization几何异构几何异构 Configuration:an arrangement of atoms that cannot be altered except by bre

5、aking chemical bonds. Geometric Isomerism立体异构立体异构 Several different isomeric forms are possible, where there are unsaturated sites along a polymer chain. -CH2-CH- H3C-C=CH2 H2C=CH-CCH3=CH2-CH2 CH2- -CH2 H C=C C=C CH3 H CH3 CH2-互为旋光异构，各有不同的旋光性CH2HXCnOptical isomerism 两者互为旋光异构体H2CCH2XHHXCH2H2CCCTactic

6、ity立构规整度立构规整度Isotactic全同立构全同立构: all the R groups lie on the same side of the plane formed by the extended-chain backbone.Syndiotactic: the R groups regularly alternate from one side to the other side. Atactic: the R groups with no preferred placement in the chains.morphology, conformationnmDnmL5 . 0

7、,105 . 24DL4105DLPlymer chainHCHCCCHHHHHHHHHH迭同式顺式构象最不稳定交叉式反式构象最稳定或或0000360,240,120,0000300,180,60Questions1. What is the difference between conformation and configuration? Which type does a helix isotactic PP belong to? If the tacticity of PP is low, can we increase it by rotation of single bond to

8、 change the conformation? Why? 3. Molecular WeightiiiMnW iiiiiwmMmM/iiiMWz iiiZMZzM/Number-averageWeight-averageZ-averageMw/Mn (PDI)Radical: 1.5-2.0High yield: 2-5Self-acceleration: 5-10Anionic: 1.01-1.05Coordination: 8-30Grafting: 20-50Molecular Weight DistributionQuestions1 Consider three samples

9、of polyisobutylene. All molecules in sample A have a molecular weight of 30,000g/mol; all those in B have a molecular weight of 70,000 g/mol; and those in C have a molecular weight of 100,000 g/mol. If 10g of A are mixed with 5 g of B and 1g of C, calculate Mn, Mw, and Mz. (section 2) Give their rel

10、ationship. Draw a curve of MW distribution and mark statistic various MWs on it. Questions 2Nylon-66 can be prepared from the monomers of hexanediamine and adipic acid though Stepwise Polymerizations, if adipic acid is excessive, and the reaction extent (P) is 0.994, the molecular weight is 00, plea

11、se write the chemical equation of the reaction between hexanediamine and adipic acid, please calculate the ratio of the two monomers. (section 3)4. Difference between radical and condensation polymerizationsCondensation polymerization1. Most of reactions are reversible.2. Polymers grow stepwise.3. A

12、ny two molecular species can react.4. Monomers disappear in the early stage of reaction.5. Molecular weight of polymer rises steadily throughout reaction.6. At any stage all molecular species are present in a calculable distribution.Radical polymerization1. Most of reactions are irreversible.2. Poly

13、mers grow chain-reacting.3. Only growth reaction adds one repeating unit at a time to the chain.4. Monomer concentration decreases steadily throughout reaction.5. High polymer is formed at once, polymer molecular weight changes little throughout reaction.6. Long reaction times give high yields but a

14、ffect molecular weight little.7. Reaction mixture contains only monomer and high polymer.Stepwise PolymerizationPolymerization characteristicsFunction degree, Relationship of reaction extent (P) with polymerization degree (Xn) and ratio of monomers ( r)Control of Molecular WeightPolymerization Techn

15、iquesNon-linear PolymerizationChain-Growth PolymerizationBasic reaction: Initiation; Propagation; Termination; Chain-transfer2. A. Initiator initiation; B. Heat initiation; C. Photoinitiation; D. Radiation initiation.3. Polymerization Techniques5. Glass transition temperature TgConceptChemical struc

16、tureMain-chainSide-group: size,Tg; flexibility,Tg ; symmetry,Tg ;, space order ,TgEffect of crosslinking structure on TgPS 87C; 0.6% bivinyl-benzene, 89.5C; 1% 94C;Tg of copolymerTg = V1Tg1 + V2Tg2; 1/Tg = w1/Tg1 + w2/Tg2 V volume portion; W: mass portion Plasticizer: PVC 81C, 45% P -30CQuestion Wha

17、t is Glass Transition TemperatureTg? Is Tg increased all the time with the molecular weight of a polymer increasing from low to ultra-high one? Point out the effect of these factors to Tg: Plasticizer, crosslinking, side-group size, side-group flexibility, side-group symmetry, side-group space order

18、. 6. Radical polym. mechanism1. Initiation (1) I-I 2I (2) I + M IM 2. Propagation IM + M IMM3. Chain-transfera. Monomer Mn + M MnH + M1 b. Solvent IMx-1M + SH IMx-1MH + S c. Macromolecules Mn + Mx-CHX-My MnH + Mx- CX-My 4. Termination a. Combination: IMx-1M + MMy-1I IMx-1MMMy-1Ib. Disproportionation

19、 IMx-1M + MMy-1I IMx + MyI I-I: initiator; I.: radical; M: monomre; SH: solventQuestion : Write the set of elementary reactions that comprise the free radical chain polymerization of vinyl acetate and methyl methacrylate, when the process is initiated by azobisisobutyronitrile. If carbon tetrachlori

20、de is added to the systems, describe the effects of chain transfer with carbon tetrachloride on the polymer composition and average molecular weight.H3CCCH3CNNNCCH3CNCH3H3CCCH3CNNN+2H3CCCH3CNH2CCHOOCCH3H3CCCH3CNH2CCHOOCCH3+H3CCCH3CNH2CCHOOCCH3H2CCHOOCCH3+H3CCCH3CNH2CHCOOCCH3H2CCHOOCCH3H2CCHOOCCH3(n-

21、1)H3CCCH3CNH2CHCOOCCH3H2CCHOOCCH3n链引发Chain Initiation：链增长Chain Propagation：vinyl acetateH3CCCH3CNH2CHCOOCCH3H2CCHOOCHCH2nCH3CCH3CNH2CHCOOCCH3H2CHCOOCCH3m+H3CCCH3CNH2CHCOOCCH3CHCHOOCCH3nCH3CCH3CNH2CHCOOCCH3H2CH2COOCCH3mH3CCCH3CNH2CHCOOCCH3H2CCHOOCCH3nCCl4H3CCCH3CNH2CHCOOCCH3H2CCHOOCCH3nCl+CCl3链终止Chai

22、n Termination：当参与四氯化碳carbon tetrachloride时：这样会导致聚合度下降,因此分子量会下降。7. Tensile strengthTensile strength measures how difficult it is to break a substance when stress is applied to pull it apart. Y- Stress at the yield point1- Elongation at the yield point2- Stress at Fracture2- Elongation at Fracture The

23、 stress-strain curves of two polymers are as follows. Please show their differences based on polymer structures.8. High performance plastics Question: Give an example of high performance plastics that is able to withstand temperature above 350C and explain why. PEEK: molecular structure, monomer, po

24、lymerization type, and property.OOCOnHOOHCOFF分子构造：单体：逐渐聚合9. Polymer processingExtrusion: A continuous process to produce thermoplastics in forms of band.Compression and heat molding Molding is mainly for the processing of thermosets. Liquid or melted materials are poured into a mold and there “harde

25、ned, i.e., polycondensed or polymerized. Phenol and epoxy resins are processed in this manner, as are styrene, acrylate et al.Injection: A reciprocating screw is used to melt a measured volume of feed. And the melt is rammed into a mold under high pressure by a hydraulically driven thrust of the scr

26、ew (thermosets).Blow molding: A gas is used to expand a hot preform, against the form of a mold cavity to produce a hollow object. Two process are used for blow molding - injection and extrusion (thermoplastics). Calendering: Molten polymer is compressed in the small gap between two heated cylinders

27、 rotating in opposite directions to produce sheets.Coating: Solutions, melts or dispersions are applied to a base. The base may be the polymer, itself, or may consist of different materials. It can remain bound to the polymer used after the process, or it may be removed.Spinning: dry-spinning, wet-s

28、pinning, electrospinningQuestion : Which processes are used for fabrication of the following matters: rubber gloves, plastic film, bottle, isolation sheet for cable, man-made leather, polyester fiber, air balloon, computer shell, throw-away cup, car bumper, coating, and nanofibers ?10. Electrospinni

29、ngQuestion: Please decribe the mechanism of the elelctrospinning process. Is it possible to produce nanotubes, nanocables, nanocomposites by electrospinning? How? 在静电纺丝过程中,将聚合物熔体或溶液加上几千至几万伏的高压静电,从而在毛细管和接地的接纳安装间产生一个强大的电场力。由于电场力和外表张力共同作用下，液滴将被拉伸成圆锥状Taylor锥。当电场力大于外表张力时，聚合物熔体或溶液经过喷丝板的孔眼后，在电场中被拉伸,最终在接纳安装

30、上构成纳米纤维。11. Universal Polymer MaterialsPlastics RubberFibersAdhesive Coatings1) additives 1. Plastics一一 Typeslubricant, thermal stabilizer: beneficial for processing；fillers, reinforcing agent, impact modifier, plasticizer:flame retardant: improve flame retardancy stabilizer: improve aging resistanc

31、e2) Universal plasticPolyolefin plastic: PE, PP, PS (ABS, ACS)Polyamide: nylon 6, nylon 66, nylon 610, nylon 1010.Polycarbonate:Polyoxymethylene:PolysulfoneP(ether ether ketone)2. RubberClassification:Nature rubber聚丁二烯橡胶聚丁二烯橡胶聚异戊二烯橡胶聚异戊二烯橡胶丁苯橡胶丁苯橡胶丁腈橡胶丁腈橡胶氯丁橡胶氯丁橡胶丁基橡胶丁基橡胶Processing:What is rubber su

32、lphuration? Please describe the main process of the rubber sulphuration. 12. Conducting polymer Proton doping Polyacetylene: Conductivity is increased to 105 S/cm Polyaniline: 103 S/cm Doping characterization Reversibility: doping-dedoping charge-dischargeQuestionsGive three kinds of polymers which

33、are conductive after doping. Describe the chemical equation for the reaction between aniline and (NH4)2S2O8 in the presence of hydrochloric acid. Give the molecular structures of three forms of polyaniline (oxidative state, reduce form, and EB state). Why are the conductivity of polyaniline differen

34、t with change in pH values ? 12. Nanopolymers Nanoparticles (0D) micro-emulsion electrospray Nanofiber (1D) electrospinning template seed technique Nanofilm (2D) layer-by-layer L-B film self-assemblyNanocomposites (Organic/inorganic hybrid materials)Nano/macroPrepare colloids in polymer solutionBlend colloids with polymer s