Development of activated carbon included natural rubber latex pillow
No Thumbnail Available
Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
Uva Wellassa University of Sri Lanka
Abstract
Latex is a milky white liquid tapped from the trunks of rubber trees (Hevea brasiliensis) and then
combined with water to create a thick suspension. In manufacturing natural latex foam rubber,
the latex suspension is whipped to a froth and poured into carousel moulds, onto a conveyor, or
into sheets and then heated to the point of vulcanization (Polyurethane Foam Association, 2000).
Activated carbon(AC) is a non-graphite form of carbon which could be produced from any
carbonaceous material. AC manufactured from coconut shell is considered superior to those
obtained from other sources mainly because of small macro pores structure which renders it
more effective for the adsorption of gas/vapour and for the removal of colour and odour of
compounds (Coconut Development Board, 2013). AC has numerous applications due to its
higher adsorption property. Thus it is capable to adsorbing volatile organic compounds
which are also air pollutant in the atmosphere.
The incorporation of activated carbon into natural rubber latex foam pillow can provi de
volatile organic compounds adsorption property apart from its cushioning effect. Many
volatile organic compounds are toxic, posing a high risk to human health as a result of their
widespread use and occurrence in laboratory, home and also workplace envi ronments
(Magureanu, Mandache, Eloy, Gaigneaux and Parvulescu, 2005).
Therefore natural rubber latex foam pillow currently available in Sri Lankan market can be
successfully value added by incorporating coconut shell based activated carbon to get the
similar cushioning effects together with air purification ability upto a certain level .
Methodology
The current study was carried out at Richard Pieris Natural Foam (RPNF) Ltd, Malwana,
Biyagama. Laboratory tests were done at RPNF, Richard Pieris Company plc and Bureau Veritas
Consumer Product Services Sri Lanka (Pvt) Ltd laboratories. Two experimental trials with
different treatments were conducted during this study. Experimental trial I was carried out to find
out the appropriate activated carbon level suitable for the natural rubber latex foam pillow. It was
compromised with eight treatment levels having 0% to 7% activated carbon levels with other
compounding ingredients as different treatments levels. Each treatment was replicated 3 times.
Experimental trial II was done in order to find the air purification ability with respect to acetone
adsorption capacity. In experiment II, both the control which has 0% activated carbon and 2% of
AC treated pillow were used to investigate the acetone (a VOC) adsorption capacity. Both
treatments were replicated 3 times. Complete Randomized Design (CRD) was conducted and
data obtained from both physical properties tests and acetone adsorption capacity was analyzed
using analysis of variance (ANOVA) procedure of Minitab 16. Mean comparison of treatments
were done using the tukey’s test.
Results and Discussion
According to the physical properties evaluation (Hardness, compression set, density and tensile
strength) the formulation with 2% of activated carbon has given a desirable physical structure
and selected in experiment trial I.
Based on the data analysis of hardness, there is significant difference (P<0.05) between control
(currently manufacturing latex pillow without AC) and the different treatment levels whereas no
significant difference between the Control and 2% of AC treatment. Therefore similar hardness
can be obtained by incorporating 2% AC into the present latex pillow formulation.
According to the results of compression set value, it is been observed that there is no significant
difference between 2%, 3% of AC treatments and control. Whereas more economical benefit
through the lower material cost can be obtained by incorporating 2% AC. As a rubber material is
compressed over time, it loses its ability to return to its original thickness. This loss of resiliency
may reduce the capability of a cushioning pad to perform over a long period of time
(Compression Set of Elastomeric Materials, 2014). Therefore lower compression set value is
better for the cushioning materials.
However density and tensile strength do not show the significant difference in all the treatments.
Generally, acceptable tensile strengths are above 0.006895 MPa depending to some extent on the
final application of the flexible foam. There are some cases where lower tensile strength foams
may be used, but it is generally advisable to use foams that have a tensile strength of at least
0.006895 MPa (Polyurethane Foam Association, 1994). In this study it shows that tensile
strength for all the treatment levels have values which are more than the acceptable value.
In experimental trial II, activated carbon treated pillow was selected due to its high acetone
adsorption capacity.
Description
Keywords
Agriculture, Export Agriculture, Crop Production, Rubber Technology, Rubber Production