A quick read on Thermosetting Plastics.
Synthetic resins that do not melt are referred to as Thermosetting Plastics, also called the ‘thermosets’. Thermosetting Plastics retain the same characteristics even in high temperatures. If you know Thermoplastics, then the best way to understand Thermosets is by seeing them as opposites to Thermoplastics. While thermoplastics would melt when heated, Thermosets would hold their shape until it reaches a point when in starts to degrade (and produces smoke).
The chemical structure for the two plastic types are different. Thermoplastics are linear polymers that are semi-crystalline or amorphous glass – in the solid form. The linearity makes the bonds weaker and hence are easily breakable. On the other hand, thermosets are cross linked polymers. This means that unless the covalent bonds between the atoms break, the plastic does not melt.
Here are some examples of Thermosets.
The most common type of thermoset plastic is Silicone (also known as ‘Polysiloxanes’ – pronounced as pol-ee-sill-OK-sane). Silicone is used in manufacturing kitchen utensils, electronic components and for implants. Silicone is highly resistant to heat, does not absorb moisture and has a long life.
A process called vulcanisation helps in cross-linking of polymer and hardens rubber. The rubber so treated is referred to as Vulcanised rubber. Common examples of applications of vulcanised rubber are footwear soles, rubber hoses, tyres, bowling balls, etc.
Another common thermosets are Polyurethane or PU in short. PUs are actually thermoset plastics that are used in producing foam sponges for use in furniture and construction.
Injection moulding process popularly makes use of thermoset plastics. Thermoset injection moulding requires that the liquid synthetic resins are put in a heated mould where the polymer cross-linking occurs. Normally, thermoset plastics are are further strengthened.
Consultiger hosts experts who can extend help to manufacturers in thermosetting. You may sign up on www.consultiger.com and post your requirement.