According to the latest American Chemical Society (ACS) Weekly PressPac, Portuguese researchers have developed a new type of microcapsule filled with perfume and embedded in fabric for production of scented suits, socks, undergarments and other clothing. Here is a link to this PressPac, from which you'll be able to read a very short note titled 'Toward perfumed-clothing: Fabric-friendly microcapsules hide unpleasant body odors.' This has been done before with microcapsules made with formaldehyde, which is toxic and known as a carcinogen. The Portuguese team is instead using polyurethane-urea, an environmentally friendly plastic and compatible with fabric to make their microcapsules which will be filled with limonene, a scent found in lemons. But read more...
You can see above several scanning electron microscopy (SEM) photos of these lemon-filled microcapsules. (Credit: Alirio E. Rodrigues and his colleagues) Here is a comment from the research team about these SEM photos. "SEM micrographs confirmed that the adhesion between textile fibber and microcapsules was effective, as can be observed in [the figure above.] Also in this figure, surface morphologies of the microcapsules can be of two types: (i) microcapsules with a soft and smooth surface and (ii) microcapsules with rough surface. These differences on surface morphology of the microcapsules wall are favorable to the release of fragrance on the textile substrate, thus increasing the durability of fragrant textiles."
The research work has been done by Alirio E. Rodrigues and his colleagues at the Laboratory of Separation and Reaction Engineering (LSRE) which belongs to Department of Chemical Engineering of the University of Porto.
Here are some details provided by the ACS. The researchers "point out that microcapsules, or submicroscopic shells, have been used for years to deliver fragrances in commercial products ranging from scratch-and-sniff stickers to the peel-apart fragrance samples found in magazine inserts. But current microcapsules are made using formaldehyde, a known cancer-causing agent that is also an environmental hazard. Safer, more effective materials are needed to extend this scented technology to textiles, the researchers say."
This research work has been published in a recent issue of the bi-weekly journal Industrial & Engineering Chemistry Research under the title "Microencapsulation of Limonene for Textile Application" (Vol. 47, No. 12, Pages 4142–4147, June 18, 2008).
Here is a link to the abstract. "Polyurethane-urea microcapsules with limonene oil as the active agent were produced by interfacial polymerization, and their suitability for textile applications was studied. Experimental conditions for the textile substrates impregnation were based on industrial requirements and set up at laboratory scale using a mini-foulard. The success of the polymerization reaction leading to the formation of the polyurethane-urea shell was checked by Fourier transform infrared spectroscopy. [...] Under the present research, a product was developed and its performance, in regard to industrial requirements, was successfully tested."
The full paper is available online, both in an HTML version and as
a PDF file (6 pages, 939 KB). The above figure and its caption were extracted from this document.
And here are some excerpts from the conclusions of this scientific paper. "In the present study we have successfully produced polyurethane-urea microcapsules by using the interfacial polymerization technique, with limonene as the active agent for textile applications. [...] The particle size distribution of microcapsules measured using a laser dispersion technique was of bimodal size distribution in volume, with a mean particle size of 10 μm. The observation of microcapsules by optical microscopy confirmed the spherical shape, the different sizes of the microcapsules with a bimodal distribution, and more importantly, the absence of agglomerates. SEM micrographs have shown an effective adhesion between microcapsules and textile fibers and also confirmed the spherical morphology and size."
Sources: American Chemical Society's Weekly PressPac, June 25, 2008; and various websites
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