Skip to main content

Thermosetting resins.

Thermosetting resins

  • Thermosetting resins are the materials that undergoes irreversible changes under the influence of heat from a fusible and soluble materials into infusible and insoluble materials through the formation of covalently cross-linked, thermally stable networks.
  • The main characteristic of thermosets is that they require curing.
  • Thermosets are generally used in liquid state and solidify and harden on curing.
  • Some resins can be part cure and hold on to what is called B stage for completely curing at latter time.
  • Some examples of thermosets include epoxies, polyesters and formaldehyde based resins.
  • The formaldehyde based resins is classified into two classes, the condensation products obtained on reacting formaldehyde with phenol (or resorcinol) called phenolic resins or phenoplasts and the products obtained on reacting formaldehyde with urea (or melamine) called amino resins or amino plastics.
  • Thermosetting resins have excellent resistance to solvents and corrosives.
  • They have high resistance to heat and high temperature.
  • They have excellent adhesion.
  • Thermosetting resins are resins that do not soften on heating. They are used when resistance to heat is important (eg kettles, plugs, laptop chargers etc). 
    Uses of Thermosetting resins
    Uses of thermosets.
  • Thermosets may also be used as an adhesives.
  • Shoe soles, foams and car tires are also made of thermosets. NEXT
    Uses of Thermosetting resins.

Comments

Post a Comment

Popular posts from this blog

Polylactic acid/PLA.

Polylactic acid/PLA. Polylactic acid is a biodegradable thermoplastic polymer . Polylactic acid is obtained from lactic acid monomer. Polylactic acid. Polylactic acid is stable to UV radiation. Polylactic acid has good resistance to moisture. Polylactic acid has good elasticity. Polylactic acid is an aliphatic polyester . It can be used as a food packaging polymer. Polylactic acid is suitable for textile fibre applications such as shirts, carpets, sportswear etc. Polylactic acid is used in implants and medical devices (screws, sutures etc). Polylactic acid is suitable for use in floor mats. Uses of Polylactic acid. Questions on Polylactic acid/PLA; Q1) What is Polylactic acid? Ans) Polylactic acid is a biodegradable thermoplastic polymer. Q2) What is the monomer of Polylactic acid? Ans) Polylactic acid is obtained from lactic acid monomer. Q3) Write some properties of Polylactic acid? Ans) Some properties of Polylactic acid are given below; ...
Post a Comment
Read more

Determination of molecular weight by osmotic pressure method

Determination of molecular weight by osmotic pressure method. Osmotic pressure method is also called membrane osmometry. This method is widely used to determine the number average molecular weight of polymers. This method is based on the phenomenon of osmosis. If a pure solvent is separated from a solution through a semipermeable membrane, due to concentration (chemical potential) difference between the solvent and solution, the solvent will flow into the solution through semipermeable membrane. The pressure applied on the solution to completely stop the flow of solvent into it through semipermeable membrane is called osmotic pressure. The theory of osmotic pressure also applies to a solution of polymers. Ordinary solution obeys Van't Hoff equation i.e π=cRT/M Where π is osmotic pressure, c  is concentration in mass per unit volume, R is gas constant, T is temperature and M is molar mass. The polymer solution are non ideal. Taking into account their deviation and us...
Post a Comment
Read more

Natural rubber (Polyisoprene).

Natural rubber (Polyisoprene) Polyisoprene (polymer of isoprene) is the primary chemical constituent of natural rubber. Thus isoprene is a monomer of natural rubber. Polyisoprene. Natural rubber is soft and sticky. It has elasticity. It can be used over a narrow range of temperature (from 10°C to 60°C). Natural rubbers are sensitive to heat. Natural rubbers are easily oxidised by air. It is insoluble in water. It is soluble in solvents like ether, carbon tetrachloride, petrol etc. Natural rubbers are used to make rubber bands. They are also used to make shoe soles and rubber tubes. They are used to make gloves, erasers, mats etc. Next Uses of natural rubber. Questions on polyisoprene; Q1) What is polyisoprene? Ans) Polyisoprene (polymer of isoprene) is the primary chemical constituent of natural rubber. Q2) What is the monomer of polyisoprene? Ans) Isoprene is the monomer of polyisoprene. Q3) Write some properties of polyisoprene? Ans) Some properti...
Post a Comment
Read more