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Colourage, Vol. LXI No. 5, Page No. 33-38 (May 2014)
Fragrance Release and Moth Repellent Activity of Natural Essential Oils
Jayant Udakhe*, Neeraj Shrivastava & Smita Honade
Textile Chemical & Colour Department
Wool Research Association, Thane, 400 607, India
*To whom all the correspondence should be addressed
E-mail: jayantudakhe@gmail.com
Abstract
Eucalyptus, lavender and citronella microcapsules were applied to wool fabric. Chemical
contents of these capsules and fragrance releasing property was tested using Gas chromatography
and subjective evaluation of fragrance release was also carried out. Citronella microcapsule
treated fabric was found to give moth repellent activity compared to other two essential oils. It
was found that fragrance release and moth repellent activity reduces after washing and dry-
cleaning. The fragrance release rate was found to be slower thus making the fragrance release
durable.
Keywords: natural essential oils, micro encapsulations, moth repellent, fragrance release
1. Introduction
The damage to the woollen textile products, wool, hair, feather and fur by wool moth has been a
continuing subject of investigation. Specially with the fact that the woollen material is costly
and is also an export commodity, certain moth proofing specifications have to be met in line with
internationally accepted methods of tests. The damage to the woollen textiles by moth larvae
throughout the world is estimated to cost millions of dollars every year. Without effective moth
proofing this damage would increase enormously and place wool at a disadvantage as a high
quality textile fibre. The insects usually remain undetected until the damage has occurred.
Fabrics, of course, can be damaged by textile pests within a few weeks of initial infestation.
Clark1 and Hartley et al2 have estimated the damage caused by a single larva to be 92.5 pounds
in one year and 100 pounds in 280 days respectively.
Different kinds of finishing treatments are given to the wool product in the industry. Some of the
colourless preparations available are Dieldrin3, Mitin LP4, Eulan WA5 and synthetic pyrethroid
Permethrin6,7. These moth proof chemicals are mostly applied in the dye bath and continuous
discharge from each dye bath provide significant toxic load to each of the affected sewage
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treatment systems and associated down stream river area. If this method of application is to be
acceptable in the future it must involve application of insecticides which have low mammallian
toxicity and are biodegradable with a low hazard to aquatic organisms.
There are natural alternatives available and researched upon as insecticidal components. The
natural pyrethrins, insecticidal esters from Chrysanthemum cinerariaefolium (Compositae), are
superior to many other insecticides in their quick-killing power, low mammalian toxicity,
biodegradability, and relatively low resistance development in insects8,9,10. Most plants contain
compounds that they use in preventing attack from phytophagous (plant eating) insects. These
chemicals fall into several categories, including repellents, feeding deterrents, toxins, and growth
regulators. Most can be grouped into five major chemical categories: e.g. nitrogen compounds
(primarily alkaloids), terpenoids, phenolics, proteinase inhibitors and growth regulators. This
repellency of plant material has been exploited for thousands of years by man, most simply by
hanging bruised plants in houses, a practice that is still in wide use throughout the developing
countries. Plants like eucalyptus, lavender and citronella are well reported to have insect
repellent properties especially mosquito repellent properties11-15.
In this paper we have studied the effect of microencapsulated natural essential oils e.g. citronella,
lavender and eucalyptus oils for their moth proofing and moth repellent activity along with the
release of fragrance.
2. Materials and Methods
2.1 Materials
Microencapsulated citronella, lavender and eucalyptus essential oils were supplied by Tanishka
Products, Mumbai (India). Wool fabric was procured from Bhutti weaver’s co-operative society
Ltd. H.P. (India). Merino wool fabric having 22.5 µm wool, warp and weft count of 2/47 Nm,
2/2 twill weave, 52/40 EPI/PPI was used in the study. Imerol PCJ liquid (wetting agent) was
supplied by Clariant, Mumbai (India). Eulan SPA was supplied by Tanatex Chemicals India Pvt.
Ltd. Thane (India). All other chemicals used were LR grade.
2.2 Fabric scouring
To remove the lubricants and antistatic, fabric was scoured using 0.5% o.w.f. Imerol PCJ liquid
at 60°C for 30 min at M: L of 1:30, hydro extracted, dried at room temperature and used for
further treatments.
2.3 Application of permethrin (Eulan SPA)
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Eulan SPA, the commercial moth proofing compound was applied to the fabric using exhaustion
method. Commercially reccommended concetration of 0.25% v/w Eulan SPA, 2.5 gpl Sodium
acetate, 2.5 gpl Acetic acid and 5 gpl Lyogen WSA (levelling agent) was used. Material to liquor
ratio was kept at 1:20. The bath was heated to 1000C and holding time was 60 min. The rate of
rise was kept at 30C/min. Then the sample was washed with cold water and dried at room
temperaure.
2.4 Application of microcapsules
Formulations were prepared using Imerol PCJ liquid 0.5gpl (wetting agent), microencapslated
citronella, lavender and eucalyptus 20 gpl. Material to liquor ratio was kept at 1:20, at pH 4.5.
The wool fabric was soaked in the formualation for 15 min. Wet pick was was adjusted to 80 %.
Sampled were dryed at 1000C followed by curing at 1300C for 2 min.
2.5 Durability to washing and dry cleaning
For testing durability of finish, the wool fabric was washed for three times using Electrolux
Wascator (Model FOM 71 CLS) laboratory washing machine. Washing was carried out using
standard test method TM 31 and the 7A washing programme was used. The finished samples
were dry cleaned for three times using standard test method ISO 3175-2 (1998). Final washed
and dry-cleaned samples were analyzed for essential oil contents using GC-MS and moth proof
testing was also carried out. Table 1 shows the sample codes and different treatments given to
the wool fabrics.
Table 1: Sample code and treatments given
Sample code Treatment given
ET Eucalyptus microcapsule treated wool fabric sample
CT Citronella microcapsule treated wool fabric sample
LT Lavender microcapsule treated wool fabric sample
PT Permethrin treated wool fabric sample
ETW Eucalyptus microcapsule treated wool fabric sample after three washing
CTW Citronella microcapsule treated wool fabric sample after three washing
LTW Lavender microcapsule treated wool fabric sample after three washing
PTW Permethrin treated wool fabric sample after three dry-cleaning
ETD Eucalyptus microcapsule treated wool fabric sample after three dry-cleaning
CTD Citronella microcapsule treated wool fabric sample after three dry-cleaning
4
LTD Lavender microcapsule treated wool fabric sample after three dry-cleaning
PTD Permethrin treated wool fabric sample after three dry-cleaning
3. Testing and characterization
3.1 Particle Size Analysis
Particle size analysis was carried out using Malvern Mastersizer 2000 model with Laser light
scattering principle. Microcapsules of eucalyptus, citronella and lavender were tested in
emulsion state using Hydro 2000S accessory.
3.2 Solid capsule and essential oil contents
Solid capsule content was determined by drying the microcapsules slurry at 600C for 6 hrs and
solid capsules contents were determined from initial and final weight of the capsules.
Quantification of loading of essential oil was carried out using GC-MS system.
3.3 Extraction of essential oils using mixer mill machine
Extraction of essential oils present in the capsules, fabric was carried out using Retsch MM 400
mixer mill machine. The capsules were crushed in hexane medium using 10 mm stainless steel
balls. Frequency of oscillation was kept at 20 cycles/second for 15 min; similar method was used
for extraction of essential oils from as finished, washed and dry-cleaned fabric. The extracts were
then analyzed using GC-MS.
3.4 Gas Chromatography Mass Spectrometry (GC-MS) Analysis
Chemicals present in the eucalyptus, citronella and lavender were analyzed using GC-MS
system. Thermo Scientific Focus GC-DSQ II system was used in the study. The GC conditions
were as follows: helium was used as a carrier gas; injector temperature, 2300 C; initial oven
temperature at 800C for 2 min, increased at 100C/min to 2800C, then held for 10 min at 2800C.
Spit ratio used was 1:20. The analysis was done using MSD detector. Component identification
was carried out by comparing the obtained MS data with those reported in Library. Standards of
citronella, eucalyptus and lavender were tested on the instruments. The amount of essential oils
present in the capsules, as finished fabric, washed, dry-cleaned fabric was estimated against the
standard.
3.5 High performance Liquid Chromatography (HPLC) Analysis
Sensitivity of Permethrin in GC-MS was observed to be lower hence analysis of Permethrin
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content in the finished, washed and dry-cleaned fabric was carried out using HPLC. The
Permethrin treated samples were reflux in methanol for 3 hrs and the extract were analyzed.
3.6 Scanning electron microscopy (SEM)
Wool fibre samples were coated with gold using JEOL JEC-550 twin coater before scanning
electron microscopy. JEOL JSM-5400 scanning electron microscope was used for studying the
surface morphology of untreated, citronella microcapsule as such finished, after three washing
and after three dry-cleaning fabric samples.
3.7 Intensity of fragrance
3.7.1 Qualitative evaluation
To have relative idea about intensity of scent the evaluation was done by the panel of 10 judges.
Evaluation was done for all as such finished, after three washing and after three dry-cleaning
fabric samples. Judges were allowed to take 2-3 whiffs for each samples and asked to rate them
in the prepared rating scale. They were also given a smell of strong coffee in between to
neutralize the smell of previous sample.
3.7.2 Quantitative evaporation
Release rate of fragrance was tested over a period of 15 days at interval of every five days. The
as finished samples were kept in incubator at 370C±20C temperature to simulate the human body
temperature. Then each sample was analyzed qualitatively using above mentioned method. The
same samples after each five day interval were also evaluated by GC-MS to quantify the amount
of essential oils present on the samples. The release rate was then calculated using the following
formula,
Release %
Initial conc. Final conc.
Initial conc. X 100
3.8 Moth repellent activity
Biological assays were done with the larvae of Anthrenus Flavipies (Le Conte) according to
visual observation of the extent of damage and weight loss of the test sample and the larval
condition of the test larvae as per the procedure described by ISO 3998-1977 (E).
The untreated and treated fabric samples were cut into discs of 40 mm diameter and conditioned
at 65%±2% relative humidity at 270C±20C temperature for 24 hrs and weighing was done. For
evaluation of the resistance of these fabric samples to the larvae of Anthrenus Flavipies (Le Conte)
wool insect pest available at Wool Research Association, Thane was used. Eleven weeks old larvae
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of Anthrenus Flavipies (Le Conte) weighing about 0.8 to 1.2 mg were used for the test. The fabric
samples of known weights were placed in contact with 15 larvae in glass Petri dishes for 14 days in
controlled atmosphere of 2720C temperature and 65 2% relative humidity in a dark cabinet.
Samples were weighted after the completion of test. The loss in mass (Δm) of each test specimen
and voracity control, due to insect feeding was determined as follows,
∆
0 3
2 1
Where,
m0 is the mass of the test specimen or voracity control before exposure to larvae;
m1 is the mass of the test specimen or voracity control after exposure to larvae;
m2 is the mean initial mass of appropriate moisture regain controls;
m3 is the mean final mass of appropriate moisture regain controls.
All the samples were assessed for damage by visual observation in terms of extent of cropping and
holes formation. The larvae condition was also accessed in terms of live, dead or pupating.
4. Results & Discussion
Detail chemical composition of the three essential oils used in this research was determined
using the GC-MS system. Table 2 shows the chemical components and the composition of the
respective oils. It was found that; eucalyptol is the major chemical constituent of the eucalyptus
oil and comprises about 82% of the total volume. Citronellal is the major chemical content
present in the citronella oil and it is around 45% of the total chemicals present. Isononyle ester is
the major component of lavender oil and it is 26% of the total volume.
Table 2: Chemical compositions of natural essential oils determined by GC-MS
Compound Name Molecular
Formula Molecular
Weight Composition
(%)
Eucalyptus
oil
Oxirane, 2,2-dimethyl-3-propyl C7H14O 114 2.32
α-Pinene C10H16 136 11.20
Benzene, 1-methyl-2-(1-
methylethyl)
C10H14 134 4.03
Eucalyptol C10H18O 154 82.46
Pentan-2-ol, 4-allyloxy-2-methyl- C9H18O2 158 13.10
3,4-Hexanediol, 2,5-dimethyl C8H18O2 146 6.83
Citronella oil 6-Octen-1-ol, 3,7-Dimethyl C10H18O 154 17.35
6-Octenal, 3,7-Dimethyl C10H20O 156 7.26
2,6-Octadien-1-ol, 3,7-Dimethyl-
(E)
C10H18O 154 44.95
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2,6-Octadienal, 3,7-dimethyl C10H16O 152 6.24
2,6-Octadien-1-ol, 3,7-dimethyl-
acetate
C12H20O2 196 4.25
3-Ethyl-2,2-Dimethyl-Oxirane C6H12O 100 3.90
Lavender oil 3,4-Hexanediol, 2,5-Dimethyl C8H18O2 146 2.11
1R- α -Pinene C10H16 136 14.04
α -Pinene C10H16 136 2.20
1,6-Octadien-3-ol, 3,7-Dimethyl C10H18O 154 14.11
Bicyclo [2.2.1]Heptan-2-one,
1,7,7-Trimethyl, (1S)
C10H16O 152 3.6
Isononyl Ester C11H22O2 186 25.93
(1s,2r,4r)-Beta-Fenchol C10H18O 154 8.29
1,6-Octadien-3-ol, 3,7-Dimethyl-,
2-Aminobenzoate
C17H23NO2 273 10.94
2-Norpinene-2-Ethanol, 6,6-
Dimethyl-, Acetate
C13H20O2 208 14.88
Table 3 shows the average particle size of the microencapsulated essential oils. It was found that
the average particle size in terms of surface weighted mean was in the range of 2-3 µm for all the
microcapsules.
Table 3: Particle size analysis of microencapsulated natural essential oils
Microcapsules Surface weighted
mean (µm)
Volume weighted
mean (µm)
Specific surface area
m2/g
Eucalyptus oil 3.453 5.556 1.74
Lavender oil 2.646 3.560 2.27
Citronella oil 2.984 3.762 2.01
Based on the formulation, it was found that the solid content ranges from 34-37 % for all the
microcapsules used in this research. Loading of essential oil inside the microcapsule was studied
using GC-MS instrument. It can be seen from the table 4 that, loading of essential oil ranges
from 24-41% on the basis of capsule slurry.
Table 4: Chemical contents on the fabric samples
Sr. No. Microcapsules Solid polymer content
in formulation %
Essential oil content
in formulation %
1. Eucalyptus 34.45 24.50
2. Citronella 37.39 41.05
3. Lavender 36.95 36.00
It can be seen from the table 5 that, citronella content on the as finished fabric was found to be
higher compared to the other two. The capsules were not durable for washing as the essential oil
content was not detected. Dry-cleaning treatment was found to reduce the chemical content on
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the fabric. Loss of finish due to washing is greater than that of dry-cleaning, as the washing
treatment is far more severe than that of dry-cleaning. SEM images (Figure 1) of citronella
capsules treated fabric shows uniform distribution of capsules on the fibre surface. After three
washings most of the capsules gets removed and few capsules can be seen on the fabric surface.
After three dry-cleaning the capsule content was found to reduce but small chunks were formed
on the fabric surface. This indicates that the capsules content reduces drastically after washing
and dry-cleaning treatments.
Figure 1: SEM images of a) untreated c) citronella capsules treated d) citronella capsules treated
after three washing e) citronella capsules treated after three dry-cleaning fabric samples
a
c
b
d
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Table 5: Chemical content in % and ratings for smell
Samples As finished After three washing After three dry-cleaning
content
%
ratings content
%
ratings release % content
%
ratings release
%
ET 0.1944 very
strong
Traces very
faint
100 0.0211 moderate 89
CT 0.3659 very
strong
Traces very
faint
100 0.0489 moderate 87
LT 0.4683 very
strong
Traces very
faint
100 0.0329 moderate 93
PT 0.0187 -- 0.0104 -- 44 0.0080 -- 57
It is observed that fragrance release is better in case of as fished fabrics. All the judges have rated
these samples to be very strong. All the samples after three washing have shown very faint
fragrance. The samples with three dry-cleaning were found to give moderate intensity of
fragrance. Release of fragrance was studied over a prolonged period at 370 C, it was found that
the release is stable and prolonged due to microencapsulation. Over a period of 15 days around
17-24% essential oil comes out indicating the prolonged release. The ratings also show that the
sample fragrance is very strong.
Table 6: Chemical content in % and ratings for smell for prolong period
Samples after 5 days after 10 days after 15 days
content
%
ratings release
%
content
%
ratings release
%
content
%
ratings release
%
ET 0.1868 very
strong
4 0.1730 very
strong
11 0.1615 very
strong
17
CT 0.3443 very
strong
6 0.3041 very
strong
17 0.2781 very
strong
24
LT 0.4487 very
strong
4 0.4441 very
strong
5 0.3854 very
strong
18
Table 7 shows the moth proofing properties of treated and untreated fabric samples. It was found
that weight loss for untreated samples is 49.73 mg and several large holes were observed. It can
be seen from figure 2 that surface of the fabric is severely damaged. Among all the fabrics
citronella microcapsule treated sample has shown some kind of resistance and the weight loss
was found to be 23.60 mg and the surface damage was also less compared to the other samples.
Table 7: Mothproofing properties of fabrics
Sample
Code
Weight loss
(mg)
Visual observations Rating
Surface cropping Surface holes Larval condition Remark
UT 49.73 4. very heavy D. several large all alive 4D/inadequately
10
cropping holes resistant
ET 35.27 4. very heavy
cropping
D. several large
holes
all alive 4D/inadequately
resistant
LT 26.11 4. very heavy
cropping
D. several large
holes
two dead 4D/inadequately
resistant
CT 23.60 4. very heavy
cropping
D. several large
holes
all alive 4D/inadequately
resistant
PT 3.75 1. No detectable
damage
A. No detectable
damage
two dead 1A/satisfactorily
resistant
ETW 42.02 4. very heavy
cropping
D. several large
holes
all alive 4D/inadequately
resistant
LTW 43.56 4. very heavy
cropping
D. several large
holes
all alive 4D/inadequately
resistant
CTW 36.41 4. very heavy
cropping
D. several large
holes
all alive 4D/inadequately
resistant
PTW 11.33 4. very heavy
cropping
D. several large
holes
two dead 1A/satisfactorily
resistant
ETD 38.33 4. very heavy
cropping
D. several large
holes
all alive 4D/inadequately
resistant
LTD 32.36 4. very heavy
cropping
D. several large
holes
all alive 4D/inadequately
resistant
CTD 25.52 4. very heavy
cropping
D. several large
holes
all alive 4D/inadequately
resistant
PTD 13.45 1. No detectable
damage
A. No detectable
damage
one dead 1A/satisfactorily
resistant
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Figure 2: Resistance to moth after 14 days test a) control b) untreated c) citronella d) lavender e)
eucalyptus f) permethrin treated fabric samples
5. Conclusion
The microcapsules of citronella, lavender and eucalyptus essential oils were applied onto wool
fabric. As finished fabric samples gives pleasant fragrance and also found to be durable over a
prolonged period. These microcapsules contents were found to reduce after washing or dry-
cleaning treatments. Citronella microcapsule treated samples were found to give moth resistance
property but the activity was found to be very less compared to commercial mothproofing agent
like permethrin.
6. References
1. C.O. Clark, Journal of Textile Institute, 19, 295 (1928)
2. R.S. Hartley, F.F. Elsworth & J. Barrit, Journal of Society of Dyers and Colourists, 59, 266
(1943)
3. M. Lipson & J. R., McPhee, Textile Research Journal, 28, 679 (1958)
4. R. J. Mayfield, Textile progress, 11(4)1(1982)
5. D. E. Wells & S.J. Johnstone, Journal of Chromatographic Science, 19, 137 (1981)
a b c
d e f
12
6. P. A. Duffield, Pesticide Science, 8(3) 279 (1977)
7. S.W. Carter, & P. A. Duffield, Journal of Textile Institute, 67(3) 77 (1976)
8. R. D. O’Brien, Insecticides, Action and Metabolism, Academic Press, New York, (1967)
9. I. Yamamoto, in R. D. O’Brien, and I. Yamamoto, Biochemical Toxicology of Insecticides,
Academic Press, New York, 193, (1970)
10. W. F. Barthel, Toxicity of pyrethrum and its constituents to mammals, In J. E. Casida (ed.),
Pyrethrum, the natural insecticides, Academic Press, Inc., New York, 123 (1973)
11. M. F. Maia and S. J. Moore, Malaria Journal, 10 (Suppl 1): S11 (2011)
12. E K. Patel, A. Gupta and R. J. Oswal, International Journal of Pharmaceutical, Chemical
and Biological Sciences, 2(3) 310 (2012)
13. N. Rani, A. Wany, A. S. Vidyarthi and D. M. Pandey, Current Research in Microbiology and
Biotechnology, 1(3) 98 (2013)
14. D. R. Barnard & R. Xue, Journal of Medical Entomology, 41(4) 726 (2004)
15. M. Arancibia, A. Rabossi, P. A. Bochicchio, S. Moreno, M. Elvira, L. Caballero, M. Carmen
G. Guillen & P. Montero, Journal of Agriculture and Food Technology, 3(3)1 (2013)