Alexium International Group Ltd. announced in April that it had developed an "innovative thermal analytical testing methodology" to measure the cooling capacity of PCM-enhanced products used in pillows, sheets and mattresses.
Alexium, based in Greer, S.C., and Perth, Australia, makes flame-retardant and PCM-enhanced fabric treatments. Dr. Robert Brookins, Alexium’s executive vice president of research and development and newly appointed interim CEO, responded to questions about the new protocol this week.
A: "At this point, the protocol has been openly shared with people in the industry, and Alexium has educated them on how to use this method. This work has been in conjunction with our customers. For more general usage, Alexium is working to introduce this as a formal test method through a standards organization."
Q: What retail pillows were evaluated (by type, if not by brand)? Do they contain microencapsulated phase change materials?
A: "All of the pillows were purchased from general retail stores and were all based on the application of the PCM to a textile component. Based on the marketing included with the pillows and the apparent method of application, microencapsulated phase change materials were used on all of these. To clarify, none of the products specifically stated that PCMs were used."
Q: What is the MPCM load in each of the four Alexium-treated pillows shown in the chart?
A: "We supply the analytical data as a testament to performance, but do not provide public information about the specific MPCM loading for products treated with our products."
Q: Are the four Alexium-treated pillows commercially available, as tested?
A: "These products represent four models that have gone into full production for commercialization by our customers."
Q: How do the results you obtained compare to other known methods used for quantifying cooling capacity, such as ASTM Standard D7984?
A: "We have used D7984 to test fabrics treated with different levels of PCM and found that MTPS provides no meaningful data. For this reason, Alexium undertook the work to develop this new test method. Based on our research, ASTM D7984 is effective for thermal effusivity and by our assessment provides insight related to sensible heat transfer; however, due to the test protocol for D7984, the thermal properties due to latent heat (i.e., PCM) are not effectively tested by that method. For our work, established DSC protocols were used as the starting place for the new method, because DSC has proven very effective at studying PCM-based materials."
Q: Do you use the DSC to measure the treated fabric’s thermal conductivity and specific heat capacity, so you can calculate the thermal effusivity?
A: "Our method is used to measure the latent heat absorbed by the PCM-treated fabric. This is important because this is the basis of the cooling effects provided by the PCM. The critical advance made with this test method is adapting established DSC methods so that they can be used reliably with PCM-treated textiles. We believe that building on an established test method is critical for the wide spread acceptance of this method."