Posts tagged as polymers

Leaving Cert. Engineering Revision Notes – Index

Polymers Condensation & Addition Polymerization General definitions Thermoplastics vs. Thermosetting plastics Joining Mig & Tig Welding Manual Metal Arc welding Oxy Acetylene welding Submerged Arc & Resistance seam welding Material Testing Material Properties General Definitions & Properties Non-Destructive Testing Destructive Testing Internal Structures of Materials Bonding Structure Defects Cooling Curves… Continue Reading →

Polymers – Differences between Thermoplastics and Thermosetting plastics

Thermosetting Plastics Bonding Bonding by Covalent bonds. Primary bonds held together by strong cross links. Process: Condensation Polymerisation Forms strong primary bonds between chains. Two monomers react to form a new molecule with water or alcohol emitted as a bi-product. The polymer cannot be resoftened. E.g. Phenol Formaldehyde Properties High melting… Continue Reading →

Polymers – General definitions

Co-Polymer: Two unlike monomers joined together in a polymer chain. E.g. Poly Vinyl Acetate Elastomer: A group of polymers consisting of linear chains that are coiled, entangled and are subject to cross linking. This allows these materials to be very elastic at room temperature. Lubricants: Make the polymer easier to mould. Various types of waxes… Continue Reading →

Polymers – Condensation & Addition Polymerization

Monomer: A monomer is a molecule of a compound which reacts with other monomers to form a polymer. Mer: A mer is a repetitive unit in a polymer.  Addition Polymerisation of Ethylene (Thermoplastics) Ethylene consists of 4 hydrogen atoms and 2 carbon atoms joined together by a double bond. (Primary and secondary… Continue Reading →