大连理工大学：《高分子化学》课程教学资源（PPT课件讲稿）第三章 自由基共聚合 Free Radical Copolymerization（主讲：李扬）

Chapter 3 Free Radical Copolymerization

1 Chapter 3 Free Radical Copolymerization

1 Introduction

2 1 Introduction

1.1 Concept Homopolymerization polymerization of one kind of monomer Copolymerization(addition polymerization polymerization of more than one kind of monomer New kinds of copolymer can be synthesized by copolymerization of different combination of various monomers Copolymer generated from same monomers can have different compositions and topologies

• Homopolymerization —— polymerization of one kind of monomer; • Copolymerization (addition polymerization) —— polymerization of more than one kind of monomer; 1.1 Concept New kinds of copolymer can be synthesized by copolymerization of different combination of various monomers. Copolymer generated from same monomers can have different compositions and topologies

Examples Styrene PS Brittle, transparent, p nt, poor solvent toleration Styrene+ Acrylonitrile SAn High impact, good solvent toleration Styrene Butadiene sBr High elasticity Styrene Acrylonitrile-+ Butadiene ABS Engineering plastics Maleic anhydride No polymer Styrene maleic anhydride SMA

4 Examples Styrene Styrene + Acrylonitrile Styrene + Butadiene Styrene + Acrylonitrile+ Butadiene PS SAN SBR ABS Brittle, transparent, poor solvent toleration High impact, good solvent toleration High elasticity Engineering plastics Maleic anhydride Styrene + maleic anhydride No polymer SMA O O O

1.2 Type of copolymer - A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B-A-B A/ternating copolymer -A-A-A-A-A-A-A-A-B-B-B-B-B-B-B-B- Block copolymer also obtained by -A-A-B-A-B-B-A-A-A-B-A-B-B-B-B-A other methods 尺 andom copo/ymer A-A-A-A-A-A-A-A-A-A-A-A-A- A-A-A- ly prepare by other methods 中∞中 Grai copolyme

1.2 Type of copolymer also obtained by other methods Normally prepared by other methods

1. 3 Nomenclature of copolymer poly(ethylene-CO-propylene) 乙烯-丙烯共聚物 poly(ethylene-y-propylene 乙烯-丙烯无规共聚物 poly(ethylene-b-propylene) 乙烯-丙烯嵌段共聚物 poly(ethylene-g-propylene) 乙烯-丙烯接枝共聚物 poly(ethylene-a-styrene) 乙烯-苯乙烯交替共聚物

poly(ethylene-co-propylene) 乙烯-丙烯共聚物 poly(ethylene-r-propylene) 乙烯-丙烯无规共聚物 poly(ethylene-b-propylene) 乙烯-丙烯嵌段共聚物 poly(ethylene-g-propylene) 乙烯-丙烯接枝共聚物 poly(ethylene-a-styrene) 乙烯-苯乙烯交替共聚物 1.3 Nomenclature of copolymer

Key topics in copolymerization ABABBAABAbBAAAbaBA Composition distribution Sequence distribution the relative amounts of each the way in which these monomer monomer unit incorporated into units are arranged within a the copolymer, A%or B% polymer chain; AA or AB

Key topics in copolymerization -ABABBAABABBAAABABA￾Composition distribution the relative amounts of each monomer unit incorporated into the copolymer, A% or B% Sequence distribution the way in which these monomer units are arranged within a polymer chain; AA or AB

2. Copolymer composition

8 2. Copolymer composition

Essential point The composition of a copolymer does not necessarily match the composition of the comonomers used in the reaction feed ratio投料比) Ethylene-vinyl acetate copolymer vinyl acetate % property 10~20 plastic 30~40 adhesive 50 rubber

9 Essential Point The composition of a copolymer does not necessarily match the composition of the comonomers used in the reaction ( feed ratio 投料比). Ethylene-vinyl acetate copolymer vinyl acetate % property 10 ~ 20 plastic 30 ~ 40 adhesive 50 rubber

Possible propagation sequences in free-radical copolymerization I-M MI I-M-M2+1 l-M2-M1+ N I一M I-M2-M2+

10 Possible propagation sequences in free-radical copolymerization