先进材料制备英文版

1、Class-1:1. Introduction,Polymer Polymer history Polymer science,As Early as Life Began: natural polymers BIOMACROMOLECULES Polysaccharides, DNA, RNA, starch, cellulose, chitin, etc.,What are Polymers?,Cellulose,Chitin,What are Polymers?,As Broad as in Daily Life: synthetic polymers,polystyrene,cis-p

2、olyisoprene,poly(vinyl pyrrolidone),What are Polymers?,Polymer polymer is a substance composed of molecules which have long sequence of one or more species of atoms or groups of atoms linked to each other by primary, usually covalent bonds.,Synthetic Polymers-Definition,Macromolecule macromolecules

3、are formed by linking together monomer molecules through chemical reaction (polymerization).,Polymer and Macromolecule used interchangeably.,Focus of This Course SYNTHETIC POLYMER!,Differences between Natural Polymers and Synthetic Polymers,Synthetic Polymers-Definition,Polymer derived from classica

4、l Greek,Autumn 2013,Synthetic Polymers-Definition,MMMMMM Or (M)n,Poly.mers many units,Long-chain-like molecules or macromolecules consisting of many repeating units (monomers) that are covalently linked, instead of physically-associated aggregates.,Molecular weight higher than 10,000 g/mol (differen

5、t from oligomers, which is composed of a few repeating units),An Example-Polyethylene,Some Basic Definitions,POLYMER A large molecule made up of small building blocks MONOMERS The building blocks HOMOPOLYMER What you get if the building blocks are all the same COPOLYMER A polymer made up of differen

6、t monomers BLEND A mixture of different polymers,Exercise 1,Please list the difference of the natural polymers with synthetic polymers (at least 2).,Exercises 2,Consider the following copolymers, which of these is an alternating copolymer? a. AA- - - AA BB - - - - BB b. ( BBB - - - BB ) ( AAA - - -

7、- AA ) ( BB - - - - BBB) 5% 90% 5% c. A B A A B B A A A B A d. A B A B A B A B ,Class-2: 2. Polymer Structure,Nomenclature Classification Polymer structure Isomerism in polymers Molecular weight,Polymers (First Order Structures),Special type: random copolymer,Polymers,Homopolymers: A polymer derived

8、 from one specie of monomer. Conventional: based on source (poly + “monomer”) or structures 2. Commercial trade names,Trade names Alkathene, Lupolen Propathene, Novolen Teflon, Fluon Styron, Hostyren HIPS ABS,2.1 Nomenclature I,Trade names Perspex, Diakon, Lucite, Oroglass, Plexiglas Darvic, Welvic,

9、 Vinoflex, Hostalit,Nomenclature II,Trade names Carbowax Terylene, Dacron, Melinex, Mylar Ultramid 6.10,Nomenclature III,2.2 Classification,Carbon chain polymer,Carbon-Oxygen polymer Carbon-Sulfur polymer Carbon-Nitrogen polymer,C C polyalkylene C C polyalkenylene C C polyalkynylene,C O polyether C

10、S polysulfone C N polyamine,O,O,Autumn 2013,Thermoplastic: Heat moldable or processible, e.g., plastics, fibers - linear or branched polymers. Thermosetting: Heat non-processible, e.g., highly crosslinked polymers. Elastomer: Polymers that can be stretched to high extensions and rapidly recover thei

11、r original dimensions when the stress is released, e.g., lightly crosslinked (chemically vulcanized, physically thermoplastic) polymers.,2.2 Classification,More Examples of Thermoplastics,/wiki/Teflon,Polymer,Autumn 2013,Examples of Thermoplastics,Autumn 2013,Thermoset Material

12、s,Autumn 2013,Thermoset Properties,Autumn 2013,2.3 Polymer Structure,Linear Polymer Branched Polymer Cross-linked and Network,Autumn 2013,Linear and Branched Polymers,Linear,Branched,Which of these is more likely to crystallize?,Autumn 2013,Linear and Branched Polymer,Branched Polymer,Linear Polymer

13、 Crystalline phase,Amorphous phase A degree of crystallinity,Autumn 2013,Linear and Branched Polymer,High density polyethylene (HDPE),Low density polyethylene (LDPE),stronger, stiffer, but less optically clear,greater optical clarity, more flexible, but less strong,Network Formation,Reacting Trifunc

14、tional Molecules (Y shaped),Reacting Tetrafunctional Molecules (X shaped),Branching can lead to the formation of densely connected networks. Network can be formed by reacting multifunctional molecules.,Autumn 2013,Network Formation,An example of forming a network from a trifunctional molecule is the

15、 reaction of phenol with formaldehyde.,PF Oligomer,PF Network,Autumn 2013,Networks - Summary,We can make networks by;,Linking together small multi-functional monomers Cross - linking already formed chains,Note; you can change properties dramatically by changing the cross-link density,Cross-linking i

16、s crucial in making elastomers with useful properties.,Autumn 2013,Configuration Polymer molecular weight is related to monomer/ initiator; Linear molecular weight conversion relationship; Narrow molecular weight range; Stabilization of the living end groups allowing the formation of telechelics, ma

17、cromers, block copolymers, and star polymers.,Living Polymerization,Ep0, Rp increases as T is increased.,Temperature,T has no effect on Xn.,Increased T will promote the chain-transfer reaction. T cationic T anionic T free,The complex parameters affect anionic polym. Polarisity , solvation, propertie

18、s of counter ions, temperature etc.,Anionic Polymerization,Mechanisms of ionic polymerization are less well understoodthan for free radical polymerization.,Summary for Chain Polymerization,3.2 Step-Growth Polymerization,Step-growth polymerization: a type of polymerization mechanism in which bi-funct

19、ional or multifunctional monomersreact to form first dimers, thentrimers, longeroligomersand eventually long chainpolymers. Polycondensation Step addition reaction Ring open polymerization,Firstly, the diol and the diacid monomer reacts to form dimer.,Then the dimer reacts with itself to form tetram

20、er or with unreacted monomer to yield trimer.,aAa: dihydric alcohol(diol); bBb: diacid,Step Polymerization,Most of the Polycondensation reactions are the typical Step-Growth Polymerization.,Step a polymer and a molecule with a low molecular weight (condensation).,Key of Polycondensation Functionalit

21、y,Functional group：an atomic group in the monomer which participates in reaction in an indicated way. e.g.： COOH，OH，NH2，Cl，NCO，COOR ， CHO ，SO3H f: the number of functional groups in the molecule which take part in the reaction (monomer, oligomer).,Type 1: Condensation Reaction,Acetic Acid,Ethanol,Re

22、versible Reaction!,Ethyl Acetate,Ester linkage,No free functional group to continue the reaction Systems with f 1,1；1,2；1,3can condense，but cannot polycondense. No macromolecule forms.,f =1, 1,Dimer,Monomer,Monomer,Type 2： System of f = 2，2,Trimer,Dimer,Monomer,Condensation Polymerization,In step-gr

23、owth polymerization, the chain is not built up one monomer at a time. The central feature of step-growth polymerization is the slow building of chains in a stepwise fashion.,Condensation Polymerization,Type 3 Systems of f = 2,n HORCOOH ORCOn + (n1)H2O n H2NRCOOH NHRCOn + (n1)H2O,General reaction： na

24、Rb Rn + (n1)ab,One monomer has both types of functional groups.,Type 4 Systems of f = 2,3；2,4；3,3,Systems of f = 2,3；2,4；3,3 can produce cross linking Polymers.,The viscosity will be suddenly increased as reaction goes to the certain degree, forming the gel -gelation. This critical point is called t

25、he gel point.,The key of cross-linking polycondensation is to control the gel point.,Dimer,adipic acid,hexamethylene diamine,+,+,Nylon,Autumn 2013,Nylon 6,6,Summary,Monomers f 2； Changeable factors : functional groups (OH,COOH,COOR, Cl,NH2，) f (linear or cross linking polycondensation); The polycond

26、ensation polymers are usually the heterochain polymers with N, O, S, P in the backbone and the functional groups in the end;,Summary,The conversion of monomer does not increase with the reaction time in the polycondensation reactions. Industrially, polycondensation can be divided into many types acc

27、ording to the group in the polymer chain. polyester, polyamide, polyether reaction Monomer concentration drops rapidly to zero early in the reaction. Polymer molar mass rises steadily during reaction. Long reaction times increase molar mass and are essential to obtain very high molar masses.,Comparison of Free-radical and Condensation Polymerizations,3.3 Polymerization Techniques,SINGLE PHASE Bulk / Melt Polymerization Solution Polymerization,MULTI - PHASE Gas / Solid Liquid / Solid Suspension Emulsion Etc.,Bulk Polymerization,The simplest method of polymer