1. Chemistry of Synthesis
A. Condensation Polymerization (functionality ≥ 2)
diol
diacid
polyester
diamine
diacid
polyamide
x : degree of polymerization (DP)
No No－ N
Xn = = (P = , extent of reaction)
N － P No
1 + P
Xw = (most probable distribution)
1－ P
Weight-fraction distribution for linear step-growth polymers
ex) PET (polyethylene terephthalate)
Nylon 6
caprolactam

2. B. Addition Polymerization
· Initiation
ex) Free radical polymerization
benzoylperoxide
· Propagation
· Termination
recombination
disproportionation
* ΔH ?
= breaking first kJ (흡수)
- new C-C bond －365kJ (방출)
ΔH = －105 kJ/mol
→ autoacceleration and gel effect (Tromsdorff effect)
ex) vinyl polymer
X = －H polyethylene (PE)
－Ph polystyrene (PS)
－Cl polyvinylchloride (PVC)
－CH3 polypropylene (PP)
－CN polyacrylonitrile (PAN)

3. Molecular Structure of Polymers
A. Linear, Branched, Cross-linked or Network
linear
branched
crosslinked
* A scale model of a typical linear polymer molecule
→ 0.5㎛ diameter and 3m long clothesline
B. Copolymers
random
alternating
graft
block

4. Industrial Polymerization Methods
A. Bulk, Solution, Suspension, Emulsion Polymerization
bulk
solution
suspension
emulsion
structure in emulsion polymerization

5. B. Gas-phase Olefin Polymerization
(fluidized-bed reactor : Union Carbide 100℃, 10기압 미만)
C. Tubular Low Density Polyethylene Process
(plug-flow reactor)
(LDPE : 1000∼3400기압, 150 ∼300℃)

6. Crosslinked or Network Polymer
Thermosets (열경화성 수지)
Crosslinked or Network Polymer
ex) FRP (fiber reinforced unsaturated polyester)
prepolymer x=8∼10 y x
unsaturated
linear chains
styrene
· Phenolics
phenol + formaldehyde → plastic bakelite
· Epoxy resin
epoxy + diamine or diacid → cross-linked
· Amino resin
urea
+ formaldehyde → cross-linked
melamine

7. Thermoplastics (열가소성 수지)
Soften upon heating and reversible regain their solid nature
A. Amorphous (無定形)
· Polymethylmethacrylate (PMMA)
· Polystyrene (PS)
· Polycarbonate (PC)
· Styrene Acrylonitrile (SAN)
B. Crystalline (結晶性)
· Polyethylene (PE), Vinyl polymers, Nylon, PET …
* Commodity plastics and Engineering plastics :
Acetal, Poltamide, Polysulfone, Polyetherimide … …
Specific volume
Temperature Tm Tg E D F C B A
A : 액체
B : 고점도 액체
C : 과냉각 액체
D : 유리성 고체
E : 과냉각 액체기지에서의
고체 결정영역
F : 유리성 기지에서
비결정성과 부분적으로 결정성인 열가소성 수지의 냉각과 응고시
온도에 따른 비체적의 변화

8. Molecular Weight (Mw) and Molecular Weight Distribution (MwD)
Mw = x M0
M0 : the molar mass of the repeat unit
x : the degree of polymerization Mn
amount of polymer Mw Mw
∑ ni Mi
Mn = ; number-average Mw
∑ ni
∑ wi Mi
Mn = ; weight-average Mw
∑ wi Mn
; polydispersity or heterogeneity index

9. What is a Polymer? A. Natural polymers and Synthetic polymers
The word polymer ; many parts
(from the Greek, polus : many and meros : parts, segments)
* monomer (monos; single)
* repeat unit
ex)
A. Natural polymers and Synthetic polymers
· Natural fibers or man-made fibers
· Natural rubbers or synthetic rubbers
· Biological polymers : protein, polysaccharide, collagen, etc
· Inorganic polymers : inorganic glasses
B. Classification of Polymers
Thermoplastics
Elastomers
Thermosets
Coating &
Adhesives
Crystalline
Amorphous
Polymers