Further documentation is available here. Once hardened a thermoset resin polyimides fundamentals and applications pdf be reheated and melted to be shaped differently.
Epoxy functional resins can be homo-polymerized with anionic or cationic catalysts and heat, or copolymerised through nucleophilic addition reactions with multifunctional crosslinking agents which are also known as curing agents or hardeners. Thermoset elastomers, which are soft and springy or rubbery and can be deformed and revert to their original shape on loading release, also decompose before melting. There are developments however involving thermoset epoxy resins which on controlled and contained heating form crosslinked networks that can be repeatedly reshaped like silica glass by reversible covalent bond exchange reactions on reheating above the glass transition temperature. There are also thermoset polyurethanes shown to have transient properties and which can thus be reprocessed or recycled.
Thermosetting polymer mixtures based on thermosetting resin monomers and pre-polymers can be formulated and applied and processed in a variety of ways to create distinctive cured properties that cannot be achieved with thermoplastic polymers or inorganic materials. The higher the crosslink density and aromatic content of a thermoset polymer, the higher the resistance to heat degradation and chemical attack. Mechanical strength and hardness also improve with crosslink density, although at the expense of brittleness. Bakelite used for making car parts. Epoxy novolac resins used for printed circuit boards, electrical encapsulation, adhesives and coatings for metal. IUPAC Compendium of Chemical Terminology. Chemistry and Technology of Epoxy Resins, ed.
Mechanically Activated, Catalyst-Free Polyhydroxyurethane Vitrimers”. Journal of the American Chemical Society. Concise Encyclopedia of Polymer Science and Engineering, ed. Handbook of Thermoset Plastics, ed. ISO 24817 Composite Repairs for Pipework: Qualification and Design, Installation, Testing and Inspection, 2015, ICS: 75. Crosslinking and thermal stability of thermosets based on novolak and melamine”. T Malaba, J Wang, Journal of Composites, vol.
2015, Article ID 707151, 8 pages, 2015. This page was last edited on 6 January 2018, at 10:26. Looking for books on Polymer Chemistry? Check our section of free e-books and guides on Polymer Chemistry now! This section contains free e-books and guides on Polymer Chemistry, some of the resources in this section can be viewed online and some of them can be downloaded.