Biomimetics and Biomimicry in Engineering

Highlighted article in prestigious IOP collection

In Publications on 2010/05/25 at 5:09 pm

My article “Porosity tailoring mechanisms in sonicated polymeric foams”, published in September 2009 (2009 Smart Mater. Struct. 18 104001; doi: 10.1088/0964-1726/18/10/104001) has been included in the collection of highlight articles published in 2009 in Smart Materials and Structures, an IOP Journal.

The importance of engineering functionally graded cellular microstructures and the motivation behind the creation of a flexible manufacturing process are the main topics of this article.  In particular, this paper reports how the manufacture of polymeric foams with a variable porosity distribution can be achieved by ultrasound irradiation during the ‘sensitive’ stages of the polymerization reaction. The energy and mass balances were studied for each of the five distinctive stages of polymerization (i.e. cream, rising, packing, gelation and solidification) in order to determine the underlying mechanisms that ultrasound employs to affect the reaction. It was concluded that controlled ultrasonic irradiation affects convective mass transfer during foaming, especially during ‘rising’ and ‘packing’ stages, and enhances the diffusion of the blowing agent (i.e. CO2(g)) from bubble to bubble in the ‘packing’ and ‘gelation’ stages. The mechanical work put into the system by ultrasound assists both the convection and diffusion by increasing the rate of mass flux. The paper concludes with experimental results that support the above hypotheses.

These findings are of great importance for the optimisation of manufacturing processes of functionally tailored materials for ‘ad-hoc’ applications, such as biomaterials, orthopaedics, medical devices or high-tech structures (e.g. aerospace, automobile).

The full collection can be found here: of 2009

My featured article here (SmartMatStruct_09_Mechanism_porosity_tailoring_Torres-Sanchez) and here:

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