Adhesives and Adhesion Part 2

Polymerization

Faculty of Polymer Eng. Sahand University of Tech. Polymerization Polymer = Monomers Polymer (Poly +Mer) 5/10/2019 Faculty of Polymer Eng. Sahand University of Tech.

Polymerization Addition Polymerization Condensation Copolymerization Radical Cationic Anionic Condensation Copolymerization Crosslinking

Polymerization Addition

Addition Polymerization + (CH2-CH2)n n CH2=CH2 Ethylene Polyethylene 5/10/2019

Types of Polymerization Reactions Radical Chain Polymerization Cationic Chain Polymerization Anionic Chain Polymerization 5/10/2019

Types of Radical Initiation: Thermal Redox Photochemical Ionizing radiations Electroinitiation Plasma 5/10/2019

Thermal Initiators 5/10/2019

Redox Initiators 5/10/2019

soluble in polar solvents only Initiation: Solubility: soluble in polar solvents only ( such as: ether)

(3) Organometallic compounds Alkyl metal compound: RLi Metal amides: NaNH2, KNH2 Grignard reagent: RMgX a. Species b. Initiation c. Solubility Initiation: Solubility: Soluble in nonpolar solvents

A pair of isolated electrons on the heteroatoms (4) Nucleophilic initiator A pair of isolated electrons on the heteroatoms For example: initiator

Polymerization Finial Conclusion: Three Steps

Polymerization: Condensation

Faculty of Polymer Eng. Sahand University of Tech. Types of Polymerization Reactions Condensation + + n HO-R-OH + n ( HOOC-R’-COOH) H-(-O-R-OCO-R’-CO-)n-OH + (2n-1) H2O A Polyester + + n (H2N-R-COOH) H(-HN-R-CO-NH-R-CO-)nOH +(n-1) H2O Nylon (a Polyamide) 5/10/2019 Faculty of Polymer Eng. Sahand University of Tech.

Overall Reaction Scheme monomer + monomer  dimer dimer + monomer  trimer dimer + dimer  teramer dimer + trimer  pentamer trimer + monomer  tetramer tetramer +pentamer heptamer n-mer + m-mer  (n+m)mer 5/10/2019 Sahand University of Technology

Sahand University of Technology Types of Monomers 5/10/2019 Sahand University of Technology

Polymerization Condensation

Sahand University of Technology 5/10/2019 Sahand University of Technology

Sahand University of Technology Alkyd Resins 5/10/2019 Sahand University of Technology

Sahand University of Technology 2- Phenolic Polymers, a) Resol 5/10/2019 Sahand University of Technology

Sahand University of Technology Curing of Resol Phenolic 5/10/2019 Sahand University of Technology

Sahand University of Technology b) Novalac Phenolics 5/10/2019 Sahand University of Technology

Sahand University of Technology Curing and Applications of Phenolics 5/10/2019 Sahand University of Technology

Sahand University of Technology 3- Amino Plastics 5/10/2019 Sahand University of Technology

Sahand University of Technology 5/10/2019 Sahand University of Technology

Sahand University of Technology 5/10/2019 Sahand University of Technology

Sahand University of Technology 4- Epoxy Resins 5/10/2019 Sahand University of Technology

Sahand University of Technology 5/10/2019 Sahand University of Technology

Sahand University of Technology 5- Polyurethanes 5/10/2019 Sahand University of Technology

Sahand University of Technology 5/10/2019 Sahand University of Technology

Sahand University of Technology 6- Polysiloxanes 5/10/2019 Sahand University of Technology

Sahand University of Technology 7- Polysulfides 5/10/2019 Sahand University of Technology

Glass Transition Temperature Transition between “rubbery” and “brittle/glassy” behavior Tg should not fall between Min and Max projected use temperatures for high stress applications A function of adhesive formulation and cure temperature