Researchers have developed polyurethane foam that is more sustainable and recyclable

A research team at the Centre for Polymer Education and Research (CERM) at the University of Liège in Belgium has developed an innovative process that rethinks the manufacture of polyurethane (PU) foam without the use of isocyanates (highly toxic substances), while polyurethane foam can also be recycled
.

Polyurethane (PU) foam is an indispensable product
in our daily life.
For decades, rigid polyurethane foam has played an important role
in energy conservation when used in the construction industry (e.
g.
floor, wall and roof insulation in buildings) or as the most effective insulation board in household items such as refrigerators (four walls and doors).
Flexible polyurethane foam is used as a comfort material for mattresses, sofas, armchairs, car seats, etc.
, and can also be applied to sound insulation and shock
resistance.

Although inexpensive, these materials are prepared from toxic compounds and are difficult to recycle
.
Christophe Detrembleur, research director of FNRS at the Centre for Polymer Education and Research (CERM) at the University of Liège, explains: "Polyurethane foam is prepared from isocyanates, which are highly reactive and toxic chemicals
.
”

Replacing this traditional chemical method with a more environmentally friendly and healthy chemical method, while harnessing an iconic waste (carbon dioxide) as a raw material, has become a priority for the production of more ecological and recyclable porous materials
.

At the same time, the production of polyurethane foams had to change
in the face of regulatory changes restricting the use of isocyanates.
Researchers at the University of Liège have developed a new process, perhaps compatible with existing industrial foaming infrastructure, to prepare isocyanate-free and recyclable polyurethane (NIPU) foam
with a blowing agent with water.

Maxime Bourguignon, a researcher in the lab and first author of the paper, said: "We have successfully imitated the foaming technology of traditional polyurethanes, replacing toxic isocyanates
with readily available cyclic carbonate compounds.
Our technology uses water and a catalyst to convert part of the cyclic carbonate into a gas (carbon dioxide), blowing it into the matrix, while the other part reacts with the amine at the same time to solidify the foam
.
The result is the formation of a solid material
with low density and regular porosity.
Our cyclic carbonate is easily obtained by the chemical conversion of carbon dioxide, which plays a dual role, forming a blowing agent and forming a polyurethane polymer matrix
.
"

Simple, modular and easy to implement, low cost to use and with a very wide range of product applications, this technology provides a new impetus
for the production of the next generation of more sustainable polyurethane foams.