HOW MICROSCOPY CAN IMPROVE RESEARCH ABOUT

MICROCAPSULES APPLIED ON TEXTILES E. Bou; L. Capablanca; P. Monllor; M. Bonet; P. Diaz

Universitat Politécnica de Valencia, Alcoy (Alicante), SPAIN, maboar@txp.upv.es

EXPERIMENTAL

Materials Denim fabrics used were 100% cotton. Microcapsules were prepared at laboratory which contained fragrances such as lavander or mint as the active part. Microcapsules application on fabrics Commercial microcapsules were applied to the surface of the fabrics by padding in a laboratory plant. A polyacrylate resin was used as a binder. Bath treatment was composed of resin, microcapsules and water. Samples were thermally fixed at 110ºC.

REFERENCES

1.  Nelson G., 2001. Microencapsulates in textile finishing Rev. Prog. Color. 31.57-64. 2.  M.Bonet, L. Capablanca, P. Monllor, P. Díaz, I. Montava. Studying bath exhaustion as a method to apply microcapsules on fabrics, Journal of the Textile Institute, DOI:10.1080/00405000.2011.596665

3.  P. Monllor, M. Bonet, L. Sanchez F. Cases. Thermal behaviour of microencapsulated flavours when applied to cellulosic fabrics. Textile research journal, 79.4. 365-380 (2009)

4.  Monllor, P., Bonet, M., Cases F. (2007). Characterization of the behavior of flavour microcapsules in cotton fabrics. European Polymer Journal, Vol. 43 (2007), pp 2481-2490, ISSN 00143057.

5.  Monllor, P., Capablanca L., Gisbert, J., Díaz P., Bonet, M.A. (2009). Improvement of Microcapsule adhesion to fabrics, Textile Research Journal, Vol. 80 (7), pp 631-635 DOI: 10.1177/0040517509346444.

Aknowledgements The authors want to thank the Spanish Ministry of Science and Innovation for the financial supported to the project ref. MAT 2009-14210-C02-01. We are also grateful to the Spanish Ministry of Education to award a FPU fellowship to Lucia Capablanca.

RESULTS AND DISCUSSION MICROCAPSULES CHARACTERIZATION When microcapsules are produced some images can be obtained in order to see if microcapsules have really been produced or it is only a mass of polymer. Figire 1 Shows apparently two samples of microcapsules. Figure 1a and 1b show apparently no important differences except the size.

Figure 1: SEM of microcapsules Figure 2: TEM from microcapsules from laboratory. (a) Correct. (b) Incorrect from laboratory a) fragrance b) polymer Because of TEM analysis it can be appreciated that despite the fact that figure 1 shows spheres in both images, figure 2 b does not belong to any microcapsule it is full of polymer. Moreover, TEM in figure 2a allows to measure the shell When samples shown in figure 1 are analysed by TEM (see figure 2), it can be observed a great difference. The ones from figure 1b show no fragrance inside but only shell polymer. In fact, they are microballs of polymers which are not full of oil fragrances as the ones from figure 1 a but of shell polymer. MICROCAPSULES APPLIED ON TEXTILES SURFACES Resin presence is necessary to bind microcapsules to fibres and it can be observed in SEM micrographs. Figure 3 shows the influence of resin presence. Figure 3: Influence of resin presence. Rubbing effect Washing effect

CONCLUSIONS Either SEM and TEM are some available techniques to determine analysis of microcapsules on fabrics after some experiences were conducted. They allowed to determine the process conditions and substantial quantities of products to be used in order to ensuring the stability and durability of microencapsulated fragrances on fabrics. TEM demonstrated if microcapsules on fabric do not smell it is not because of the microcapsule size but, because it is not full of fragrance. This technique also can help to analyse the sell thickness. If it is extremely soft it will show no resistnace. SEM is useful to determine the presence of microcapsules on fibres and determine the influence of different common agents such as rubbing or washing.

INTRODUCTION

This work is focused on determining the importance of Electron Microscopy to study studying microcapsules on cotton fabrics. It has been long ago since it is known microcapsules can be applied on textiles[1]. Some works have been focused in evaluating the influence of the the system to apply microcapsules [doi], thermal behavior [3], their behaviour during laundering [4] or the inluence of binder [5] Two experimental techniques, scanning electron microscopy (SEM) and Transmision electron microscopy (TEM) have been used to determine the microcapsules behavior on fabrics in different aspects such as microcapsules characterization, their presence on textiles and their behavior when rubbing or after laundering the fabrics. SEM: has been performed with a scanning electron microscope (SEM) Phenom microscope (FEI Company) was used. Each sample was fixed on a standard sample holder and sputter coated with a gold –platinum mixture. Samples were then examined with suitable accelerating voltage and magnification. Moreover, a JEOL JSM-6300 scanning electron microscope (SEM) was used. TEM: Transmission electron microscopy (TEM) was performed with a JEOL JEM-2010 model provided with a EDS system OXFORD instruments INCA Energy TEM100.

a) b)

0 g/L 5 g/L

10 g/L 15 g/L

It can be appreciated that when resin is not applied the microcapsules size is lower than the ones adhered with resin. Moreover, if the binder concentration increases up to 15 g/L it acts as an iglu effect and does not allow the oil to be spred easily.

0 g/L

5 g/L 10 g/L

Figure 5 shows SEM micrographs of cotton fabrics after 20 washing cycles. It can be observed that o n l y f e w s m a l l s i z e d microcapsules remain on fabrics after the application of 20 washing cycles and if binder was used.

Figure 5: SEM micrographs of cotton fabrics after 20 laundry cycles of Standard Iso 105 C10

Figure 4 shows SEM images from cotton rubbed in wet conditions. It shows how some microcapsules remain on fabric while some fibres are degradated.

Figure 4: SEM micrographs of cotton fabrics rubbed as Standard ISO 105 X11

MICROCAPSULES PREPARATION Sometimes baths are prepared and reused in other processes with the same composition or otherwise it must be thrown. When bath was prepared previously the yield was reduced, the fragrance smell decreased if compared with the samples treated with the baths just immediately it had been prepared. SEM demonstrated that microcapsules shouldn´t be prepared in advance. Some of them were deflated because of the contact with water what means the fragrance has been lost in water and would not remain on fabric. Figure 1a shows microcapsules in cotton fibres treated immediately the bath had been prepared whereas figure 1b shows microcapsules on cotton with a bath which had been prepared in advance.

Figure 1a: Microcapsules from bath just prepared.

Figure 1b: Microcapsules from bath prepared in advance.