Page 70 - Plastics News Issue November - 2024
P. 70
IN THE NEWS
Challenges in Recycling Thermoset Plastics 4. Environmental Impact: On the other hand,
recycling of thermoset plastics is slightly
1. Irreversible Bonding Structure: One major more complex and at some times can be
difficulty about recycling thermoset plas- very cumbersome and requires energy and
tics is in their form, chemically. Thermosets chemicals to handle the material. This is usu-
solidify during curing through the formation ally costly and time consuming, hence it is
of covalent bonds which make the material usually unprofitable for many organizations
very fragile. We have already noted that the to undertake. In addition, the material that is
thermosets, unlike the thermoplastics, can- recycled may not possess the same charac-
not be reprocessed by heating the mass, teristic as the thermoset; as such the use of
in other words, they cannot be remoulded. the material is less preferable and thus re-
The structure of cross linking won’t allow the stricted.
common techniques of recycling applica-
tions so when thermosets have been used 5. Complex Composition of Thermosets: Ther-
up they are usually dumped or chucked moset plastics are thus normally processed
away to the landfill. together with other material to improve its
characteristic property and these are more
2. Limited Infrastructure for Recycling: Recy- difficult when it comes to recycling. For ex-
cling structures deployed internationally ample, thermosets applied in wind turbine,
are primarily intended for recycling thermo- vehicle, etc. are typically reinforced or filled
plastic materials. Thermosets cannot be re- composites of polymers. These material
cycled in the conventional ways since they cannot be separated easily and they need
have crossed their recycling threshold; there special tools for that, and these factors add
is limited capacity for handling them. Even complexity to the recycling process.
in places where there are good recycling
plants, there is usually emphasis on easy to Innovations in Recyclable Thermoset Plastics
recycle products like PET, HDPE, LDPE. Due
to their lack of proper infrastructure, thermo- Nevertheless, there has been a number of in-
sets end up in the following resource cycle: teresting developments in the use of recyclable
Resource wastage, environmental pollution thermoset plastics as presented below. Some of
through landfilling or incineration. the new approaches exercised by the research-
ers and engineers for developing recyclable
3. High Energy and Financial Costs: Recycling thermosest are in the pipeline like designing a
of thermoset plastics is a more challenging reversible bond and bio based material.
process and at times quite energy-intensive
as well as chemically intensive to manage the 1. Reversible Thermoset Polymers: Another
material. This is normally expensive and time relatively recent work in the sphere of recy-
consuming thus making it uneconomical for clable thermoset plastics is so-called vitrim-
many organizations to pursue. Further, the ers. Vitrimers are thermoset plastics that can
material that is recycled may not have the be reformed and recycled by the use of heat
same properties as the thermoset, making or chemicals only. They are capable of being
its use less preferable and its usage limited. processed when their covalent bonds can be
temporarily severed to ‘reset’ the material
70 PLASTICS NEWS November 2024
