Polydimethylsiloxane (PDMS) is one of the best known elastomers and has been used in
several areas of activity, due to its excellent characteristics and properties, such as biocompatibility,
flexibility, optical transparency and chemical stability. Furthermore, PDMS modified with other
materials promotes the desired changes to broaden its range of applications in various fields of
science. However, the heating, mixing and degassing steps of the manufacturing process have
not received much attention in recent years when it comes to blending with solid materials. For
instance, PDMS has been extensively studied in combination with waxes, which are frequently in
a solid state at room temperature and as a result the interaction and manufacturing process are
extremely complex and can compromise the desired material. Thus, in this work it is proposed a
multifunctional vacuum chamber (MVC) with the aim to improve and accelerate the manufacturing
process of PDMS composites combined with additives, blends and different kinds of solid materials.
The MVC developed in this work allows to control the mixing speed parameters, temperature control
and internal pressure. In addition, it is a low cost equipment and can be used for other possible
modifications with different materials and processes with the ability to control those parameters. As
a result, samples fabricated by using the MVC can achieve a time improvement over 133% at the
heating and mixing step and approximately 200% at the last degassing step. Regarding the complete
manufacturing process, it is possible to achieve an improvement over 150%, when compared with
the conventional manufacturing process. When compared to maximum tensile strength, specimens
manufactured using the MVC have shown a 39% and 65% improvement in maximum strain. The
samples have also shown a 9% improvement in transparency at room temperature and 12% at
a temperature of about 75 C. It should be noted that the proposed MVC can be used for other
blends and manufacturing processes where it is desirable to control the temperature, agitation speed
and pressure.
This research was partially funded by Portuguese national funds of FCT/MCTES (PIDDAC)
through the base funding from the following research units: UIDB/00690/2020 (CIMO)
and UIDB/04077/2020 (MEtRICs). The authors are grateful for the funding of ANI, FCT and
CIMO through the projects POCI-01-02B7-FEDER-069844, and EXPL2021CIMO_01, respectively.
The authors are also grateful for the partial funding of FCT through the projects EXPL/EMEEME/
0732/2021, NORTE-01-0145-FEDER-030171 (PTDC/EMD-EMD/30171/2017) funded by COMPETE2020,
NORTE2020, PORTUGAL2020, and FEDER.
