Tổng quan về Polymer

POLYMER SCIENCE AND TECHNOLOGY Mai Anh Tuan, HUST CHAPTER ONE 1. Historical Development 2. Basic concept and definition 3. Classification Historical Development • Beginning of time, polymer form the very basis (building blocks) of life (animals, plants) • We began to understand the true nature of polymer in mid 20 th century. • First man-made polymer: plastic – First discovery: nitrocellulose or cellulose nitrate, first proposed by Alexander Parkes but patent filed by John Wesley Hyatt in 1868 Historical Development • Phenol–formaldehyde plastics (phenolics), reported by Dr. Leo Hendrick Baekeland in 1909 , was the 1 st man-made polymer Historical Development Historical Development Historical Development REMARK • Empirical synthesis • Chemical composition with virtually no attention paid to structure for 1 st generation of polymer. • 1 st half of the 20th century, extensive organic and physical developments led to the 1 st understanding of the structural concept of polymers-long chains or a network of covalently bonded molecules. Historical Development • Hermann Staudinger: PolyOxyMethylene (a.k.a PolyAcetal), Rubber • Nobel Prize in Chemistry in 1953 Historical Development • W. T. Carothers: Nylon [...]... oligomers and polymers Basic Concept & Definition • The degree of polymerization represents one way of quantifying the molecular length or size of a polymer • This can also be done by use of the term MW MW (Polymer) =DP × MW(Repeat Unit) • Your Turn: calculate the MW – Polystyrene, DP= 8 – Commercial Polystyrene: DP = 1000 • What is the molecular weight of polypropylene (PP), with a degree of polymerization... its polydispersity? – Note that Xn and n(DP) defines the same quantity for two slightly different entities The degree of polymerization for a single molecule is n But a polymer mass is composed of millions of molecules, each of which has a certain degree of polymerization Xn is the average of these Basic Concept & Definition CLASSIFICATION OF POLYMER A NATURAL VS SYNTHETIC • Naturally synthetic All the... other hand, are examples of polymers of plant origin and have relatively simpler structures than those of enzymes or proteins CLASSIFICATION OF POLYMER A NATURAL VS SYNTHETIC • There are a large number of synthetic (man-made) polymers consisting of various families: fibers, elastomers, plastics, adhesives, etc Each family itself has subgroups CLASSIFICATION OF POLYMER B POLYMER STRUCTURE 1 Linear,... CLASSIFICATION OF POLYMER 1 Linear, Branched or Cross-linked, Ladder vs Functionality CLASSIFICATION OF POLYMER 1 Linear, Branched or Cross-linked, Ladder vs Functionality - The presence of these branch points ultimately leads to a cross-linked infusible and insoluble polymer with structures such as (20) YOUR TURN • Show the polymer formed by the reaction of the following monomers Is the resulting polymer linear... Basic Concept & Definition • Almost all synthetic polymers irrespective of the method of polymerization (formation), length of a polymer chain determined by purely random events Basic Concept & Definition • Number-average MW represented by M w and M nthe weight-average molecular weight • Nylon 11 has the following structure • If the number-average degree of polymerization, Xn, for nylon is 100 and M w=... molecule(s) must be at least bifunctional CLASSIFICATION OF POLYMER 1 Linear, Branched or Cross-linked, Ladder vs Functionality CLASSIFICATION OF POLYMER 1 Linear, Branched or Cross-linked, Ladder vs Functionality The transformation of this viscous liquid into a hard, cross-linked three-dimensional molecular network involves the reaction of the prepolymer with reagents such as amines or Lewis acids This... involves a rearrangement of electrons Basic Concept & Definition • Structural unit - residue from the monomer • Degree of Polymerization (DP), n, specifies length of polymer molecules • Reaction can form dimer, trimer Then, they can mix together Basic Concept & Definition • Low-MW polymerization products as dimers, trimers,, etc., are referred to as oligomers, generally possess undesirable thermal and... single functional group Besides, even though the interlinking capacity of a monomer is ordinarily apparent from its structure, functionality as used in polymerization reactions is specific for a given reactionse monomers bifunctional CLASSIFICATION OF POLYMER 1 Linear, Branched or Cross-linked, Ladder vs Functionality • Ex.: A diamine like hexamethylenediamine has a functionality of 2 in amide-forming... butadiene would be expected to prescribe a functionality of 4 for this molecule CLASSIFICATION OF POLYMER 1 Linear, Branched or Cross-linked, Ladder vs Functionality • Butadiene may indeed be tetrafunctional, but it can also have a functionality of 2 depending on the reaction conditions CLASSIFICATION OF POLYMER • Reaction between two monofunctional monomers such as in an esterification • Reactive groups... bifunctional molecules react? CLASSIFICATION OF POLYMER • The ester resulting from this reaction is itself bifunctional, being terminated on either side by groups that are capable of further reaction • In other words, this process can be repeated almost indefinitely The same argument holds for polyfunctional molecules It is thus obvious that the generation of a polymer through the repetition of one or a