Abstract:
|
It is well known the relevance given to the study of heat transfer in polymer foams,
as one of the main applications is as lightweight thermal insulating elements. Alongside
some of the possible strategies for improving the thermal insulating characteristics of
polymer foams, there is also a tremendous interest in further extending the applications of
these materials, mainly focusing on improving their poor mechanical properties.
Although there is a great deal of interest in preparing and studying polypropylene
foams, largely due to their good balance of properties and reduced cost, there is still lack
of information regarding their mechanical and thermal conduction characterizations. With
that in mind, this chapter considers the preparation, structure and properties of different
polypropylene and polypropylene-based nanocomposite foams, focusing on the
importance of the foam’s cellular structure and microstructure characteristics and/or
filler’s orientation and dispersion in the mechanical and mainly thermal conduction
properties, with the main objective of developing new multifunctional thermal insulating
lightweight materials for diverse applications.
A great deal of importance is given to some of the different strategies used towards
the development of rigid polypropylene-based foams to be used as structural elements
with improved thermal insulation characteristics. Particularly, we have focused on
reducing the value of thermal conductivity via cellular structure control, as it is known to
strongly depend on cellular structure characteristics such as cell size, cell density and cell
anisotropy. First of all we have addressed the importance of the foaming process and
foaming parameters in establishing a certain cellular structure, and secondly in the possibilities of adding high aspect ratio nano-sized fillers, that act as cell nucleating sites,
promoting the formation of finer closed-cell foams. |