Microencapsulation provides an important tool for cosmetic and/or pharmaceutical industry, enabling protection and controlled release of several active agents. The encapsulation of essential oils in core-shell or matrix particles has been investigated for various reasons, e.g., protection from oxidative decomposition and evaporation, odor masking or merely to act as support to ensure controlled release. A large number of microencapsulation methods have been developed in order to be adapted to different types of active agents and shell materials, generating particles with a variable range of sizes, shell thicknesses and permeability, providing a tool to modulate the release rate of the active principle. With this work, an overview regarding properties and applications of essential oils and biodegradable polymers in the cosmetic field, focusing the use of polylactide as the base material to encapsulate thyme oil, as well as of microencapsulation processes with a particular emphasis on the coacervation, will be presented.2

No 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 minifoulard. The success of the polymerization reaction leading to the formation of the polyurethane-urea shell was checked by Fourier transform infrared spectroscopy. Particle size distributions and morphology of the microcapsules were studied using a particle size analyzer (Coulter LS230), optical microscopy, and scanning electron microscopy. The effectiveness of the textiles impregnation and the durability of the impregnation effect were evaluated by scanning electron microscopy and by headspace/GC/FID. Under the present research, a product was developed and its performance, in regard to industrial requirements, was successfully tested.

Microencapsulation reveals numerous advantages over conventional applications of flavors or fragrances. Thus, the goal of this work was to study the release rate of thyme oil through the polylactide (PLA) microcapsules prepared by coacervation. Microcapsules have spherical shape and a mean particle size of 36 μm. The results show that the release of thymol is faster in the first hour and remains almost constant in the next days. Moreover, it was observed that the release of the polar compounds of thyme oil is faster than the apolar ones. The diffusion coefficient in the first hour of release was 1.39 × 10–15 m2/s for thymol and 5.21 × 10–17 m2/s for p-cymene. For a period of 5 days, diffusion coefficients of 3.81 × 10–17 m2/s for thymol and 1.43 × 10–18 m2/s for cymene were determined. The diffusion of thyme oil from the PLA cross-linked membrane was dependent on the microcapsules morphological characteristics.

The evaluation of the performance of new products to be released on the market is essential to measure its acceptability by consumers. In this work, the performance of an added‐value product, microencapsulated perfumes applied on textiles for man suits, was predicted and evaluated. The odor intensity and character of the perfume ingredients was measured by headspace gas chromatography after dry cleaning and abrasion tests on textiles impregnated with microcapsules. The evaporation and diffusion of the fragrances in the encapsulated perfume was assessed. For this type of application, limonene has shown a better performance in the perfume mixture, being the dominant note over time and distance. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1939–1950, 2012

The objective of this work is to prepare microcapsules of polylactide-containing thyme oil by coacervation using a variety of nonionic surfactants with different hydrophilic−lipophilic balance (HLB) values and evaluate the encapsulation efficiency of polar and apolar compounds of oil. Thus, Tween 20, Tween 80, Tergitol 15-S-9, and a combination of Tergitol 15-S-9 with Span 85 have been used. The HLB value was comprised between 11 and 16.5. For all the studied cases, microcapsules are spherical in shape and have bimodal particle size distribution with mean size between 30 and 40 μm. The amount of encapsulated thyme oil reaches a maximum of 65% for Tergitol 15-S-9, a polyglycol ether surfactant with a HLB value of 13.3. The results confirm the dependence of the encapsulation efficiency as result of the hydrophobic properties of the surfactants. Moreover, it was confirmed a preferential encapsulation of apolar compounds of thyme oil in detriment of polar ones.

No abstract

No abstract