Ethylene Butyl Acrylate Copolymer (EBA) presents several properties, such as flexibility, which make it a very promising material for applications where comfort is required . However, despite of its potential, there is a lack of studies in the literature related to the foamability of EBA.
This work reports for the first time the production and characterization of open cell EBA foams produced by a two-step compression molding process. Based on the cellular structure interconnectivity, two types of open cell materials are presented in this study: low density EBA foams with high tortuosities and low density EBA foams with low tortuosities.
The cellular structure tortuosity is defined as the ratio between the real and the shortest distances that the gas molecules have to cover from one side to the other side of the foamed material . The cell opening in EBA foam is due to the presence of holes on the cell walls. The size and number of holes determine whether the sample is low tortuous (few and smaller holes) or high tortuous (more and larger holes). This cellular structure interconnectivity differs clearly from that of the flexible open cell polyurethane (PU) foams, which typically present only struts without the presence of cell walls .
The main objective of this work is to characterize the mechanical, acoustic and oil absorptive properties of open cell EBA foams to determine the effect of the cellular structure tortuosity on the properties. It has been observed, that this parameter plays a key role on the final properties, being critical depending on the final application of the cellular material.
Finally, with the purpose of framing these materials inside the field of polyolefin foams, the obtained results for open cell EBA foams have been compared with those obtained for ethylene vinyl acetate (EVA) and low density polyethylene (LDPE) foams with low and high tortuosity produced in our facilities. Furthermore, a flexible open cell PU used for comfort applications has been also included in the comparative study. The promising results obtained for open cell EBA foams with low tortuosity indicate that this material can be a potential alternative to open PU foams in comfort, acoustic insulation and in oil absorptive applications.