This document summarizes a study that used a solvent-swelling method and electron microscopy to visualize the degradation of natural rubber (NR) particle networks in household latex gloves buried in soil for various time periods (3, 12, and 18 months). The study found that the integrity of the rubber particle network degraded more over time for treated gloves compared to untreated gloves. At 18 months, the rubber particle network had completely broken down and dispersed for both treated and untreated gloves. The solvent-swelling method provided clearer images of the degradation of the rubber particle network compared to conventional electron microscopy methods.
Effect of degumming conditions on the deformation behavior of banana (Musa ac...IJERA Editor
The current work investigates the effects of degumming conditions on the deformation behavior of banana (Musa accuminata) pseudo-stem fiber. The sodium hydroxide (NaOH) concentration was varied from 0.75M to 1.5M, treatment temperature from 80°C to 110°C and treatment time from 60 to 180 minutes. The fibers exhibited a continuous strain hardening on loading, the rate of which decreased with increasing NaOH concentration, treatment time and treatment temperature. An increase in NaOH concentration at constant treatment time and temperature had a degrading effect on the fiber’s breaking tenacity and breaking extension. Similarly, an increase in treatment time at a constant NaOH concentration and treatment temperature, reduced fiber’s breaking tenacity and breaking extension. Degumming of banana fibers at a NaOH concentration of 1M at 90°C for 90 minutes gave a good compromise between breaking tenacity and breaking extension.
SYNTHESIS AND CHARACTERIZATION OF A NOVEL MATERIAL FOR HIGH TEMPERATURE RESIS...Soutam Banerjee
Synthesized Lanthanum Zirconate (LZ) powder from solid state sintering and co-precipitation techniques
Carried out the compaction of the powders to form pellets and sintering at 1600 ᴼC
XRD analysis of solid state mixing sintered pellet and the co-precipitated sintered pellet
Micro-hardness and Weibull analysis of surface and cross-section of the co-precipitated sintered pellet
Effect of degumming conditions on the deformation behavior of banana (Musa ac...IJERA Editor
The current work investigates the effects of degumming conditions on the deformation behavior of banana (Musa accuminata) pseudo-stem fiber. The sodium hydroxide (NaOH) concentration was varied from 0.75M to 1.5M, treatment temperature from 80°C to 110°C and treatment time from 60 to 180 minutes. The fibers exhibited a continuous strain hardening on loading, the rate of which decreased with increasing NaOH concentration, treatment time and treatment temperature. An increase in NaOH concentration at constant treatment time and temperature had a degrading effect on the fiber’s breaking tenacity and breaking extension. Similarly, an increase in treatment time at a constant NaOH concentration and treatment temperature, reduced fiber’s breaking tenacity and breaking extension. Degumming of banana fibers at a NaOH concentration of 1M at 90°C for 90 minutes gave a good compromise between breaking tenacity and breaking extension.
SYNTHESIS AND CHARACTERIZATION OF A NOVEL MATERIAL FOR HIGH TEMPERATURE RESIS...Soutam Banerjee
Synthesized Lanthanum Zirconate (LZ) powder from solid state sintering and co-precipitation techniques
Carried out the compaction of the powders to form pellets and sintering at 1600 ᴼC
XRD analysis of solid state mixing sintered pellet and the co-precipitated sintered pellet
Micro-hardness and Weibull analysis of surface and cross-section of the co-precipitated sintered pellet
Purpose
Fluid-bed coating of microparticles using aqueous polymer dispersions is a challenge due to particle agglomeration. Agglomeration is an undesirable phenomenon especially for modified release products resulting in inconsistent and unreliable coating thickness and drug release profile. Due to the small particle size and relatively high coating level, the determination of agglomerated particles is complicated and cannot be performed by common methods such as sieve analysis and observation under light microscope.
The objective of this study was to investigate appropriate methods to determine the internal structure of coated microparticles to support decision making in the formulation and coating process development.
Synthesis of new dental nanocomposite with glass nanoparticles Article 7, Vol...Nanomedicine Journal (NMJ)
Objective(s):
The aim of this study was to synthesis new dental nanocomposites reinforced with fabricated glass nanoparticles and compare two methods for fabrication and investigate the effect of this filler on mechanical properties.
Materials and Methods: The glass nanoparticles were produced by wet milling process. The particle size and shape was achieved using PSA and SEM. Glass nanoparticles surface was modified with MPTMS silane. The composite was prepared by mixing these silane-treated nanoparticles with monomers. The resin composition was UDMA /TEGDMA (70/30 weight ratio). Three composites were developed with 5, 7.5 and 10 wt% glass fillers in each group. Two preparation methods were used, in dispersion in solvent method (group D) glass nanoparticles were sonically dispersed in acetone and the solution was added to resin, then acetone was evaporated. In non-dispersion in solvent method (group N) the glass nanoparticles were directly added to resin. Mechanical properties were investigated included flexural strength, flexural modulus and Vickers hardness.
Results:
Higher volume of glass nanoparticles improves mechanical properties of composite. Group D has batter mechanical properties than group N. Flexural strength of composite with 10%w filler of group D was 75Mpa against 59 Mpa of the composite with the same filler content of group N. The flexural modulus and hardness of group D is more than group N.
Conclusion:
It can be concluded that dispersion in solvent method is the best way to fabricate nanocomposites and glass nanoparticles is a significant filler to improve mechanical properties of dental nanocomposite.
Accelerated ageing of newsprint paper: Changes in swelling ability, WRV and e...Michal Jablonsky
The present paper deals with the effect of accelerated ageing on the ability of fibres to undergo saturation with water and the corresponding swelling kinetics. Changes in the surface charge of aged paper fibres were also investigated. Accelerated ageing was performed with newsprint paper at 98 °C and 50% RH during 0, 3, 5,7, 10, 15, 20 and 30 days. The rate and maximum swelling of accelerated aged paper in water were obtained with a modified monitoring unit measuring wood swelling ability. Since paper swells extremely fast in water, even at 30 °C, this apparatus made it possible for the first time to obtain accurate kinetic data on aged paper swelling in water. The polyelectrolyte titration technique was used to investigate changes in the surface charge on fibres from accelerated aged paper.
Presented in the 15th NCB International Seminar held from 05.12.- to 08.12.2017, the Indian organization for research and technological development under the administrative control of the Ministry of Commerce and Industry of the Government of India held the 15th edition of the NCB International Seminar, which again took place at the Manekshaw Centre in New Delhi.Was the 1st presenter in the Technical session:'Other Building Materials & Binders' held in Ashoka Convention Hall.Due to other important commitments Mr. Suresh Prabhu, Minister of Commerce and Industry, Government of India, was unable to attend the NCB International Seminar personally. Nevertheless he was able to welcome the delegates and to hold his inaugural address via video live stream. Regarding the technological development of the cement industry, one of the main challenges for the future perspective will be the limited materials. To help cope with the future challenges he confirmed the support of the Ministry of Commerce and Industry.
In this work, we synthesized and characterized mesoporous thin fims
of SiO 2 and NiTiO3 structured by a surfactant called Brij58. These fims
were fabricated by the method of dip coating and the best conditions for
well-structured thin fims were investigated as a function of surfactant
concentration and diffrent types of substrates. These fims have been
characterized by X-ray reflctivity which was calculated using the matrix
formalism. We demonstrated that the silicon substrate had a great effct
on the structure and porosity of the fabricated fims for both SiO2 and
NiTiO3. Furthermore, we found that mesoporosity has been increased
as a function of the surfactant concentration in the solution. This experimental procedure allows also to produce NiTiO3 powders which have
been characterized by X-ray diffaction. The XRD coupled to the crystallographic software “Maud”shows that the samples are constituted by 98,
2% NiTiO 3 powders.
Purpose
Fluid-bed coating of microparticles using aqueous polymer dispersions is a challenge due to particle agglomeration. Agglomeration is an undesirable phenomenon especially for modified release products resulting in inconsistent and unreliable coating thickness and drug release profile. Due to the small particle size and relatively high coating level, the determination of agglomerated particles is complicated and cannot be performed by common methods such as sieve analysis and observation under light microscope.
The objective of this study was to investigate appropriate methods to determine the internal structure of coated microparticles to support decision making in the formulation and coating process development.
Synthesis of new dental nanocomposite with glass nanoparticles Article 7, Vol...Nanomedicine Journal (NMJ)
Objective(s):
The aim of this study was to synthesis new dental nanocomposites reinforced with fabricated glass nanoparticles and compare two methods for fabrication and investigate the effect of this filler on mechanical properties.
Materials and Methods: The glass nanoparticles were produced by wet milling process. The particle size and shape was achieved using PSA and SEM. Glass nanoparticles surface was modified with MPTMS silane. The composite was prepared by mixing these silane-treated nanoparticles with monomers. The resin composition was UDMA /TEGDMA (70/30 weight ratio). Three composites were developed with 5, 7.5 and 10 wt% glass fillers in each group. Two preparation methods were used, in dispersion in solvent method (group D) glass nanoparticles were sonically dispersed in acetone and the solution was added to resin, then acetone was evaporated. In non-dispersion in solvent method (group N) the glass nanoparticles were directly added to resin. Mechanical properties were investigated included flexural strength, flexural modulus and Vickers hardness.
Results:
Higher volume of glass nanoparticles improves mechanical properties of composite. Group D has batter mechanical properties than group N. Flexural strength of composite with 10%w filler of group D was 75Mpa against 59 Mpa of the composite with the same filler content of group N. The flexural modulus and hardness of group D is more than group N.
Conclusion:
It can be concluded that dispersion in solvent method is the best way to fabricate nanocomposites and glass nanoparticles is a significant filler to improve mechanical properties of dental nanocomposite.
Accelerated ageing of newsprint paper: Changes in swelling ability, WRV and e...Michal Jablonsky
The present paper deals with the effect of accelerated ageing on the ability of fibres to undergo saturation with water and the corresponding swelling kinetics. Changes in the surface charge of aged paper fibres were also investigated. Accelerated ageing was performed with newsprint paper at 98 °C and 50% RH during 0, 3, 5,7, 10, 15, 20 and 30 days. The rate and maximum swelling of accelerated aged paper in water were obtained with a modified monitoring unit measuring wood swelling ability. Since paper swells extremely fast in water, even at 30 °C, this apparatus made it possible for the first time to obtain accurate kinetic data on aged paper swelling in water. The polyelectrolyte titration technique was used to investigate changes in the surface charge on fibres from accelerated aged paper.
Presented in the 15th NCB International Seminar held from 05.12.- to 08.12.2017, the Indian organization for research and technological development under the administrative control of the Ministry of Commerce and Industry of the Government of India held the 15th edition of the NCB International Seminar, which again took place at the Manekshaw Centre in New Delhi.Was the 1st presenter in the Technical session:'Other Building Materials & Binders' held in Ashoka Convention Hall.Due to other important commitments Mr. Suresh Prabhu, Minister of Commerce and Industry, Government of India, was unable to attend the NCB International Seminar personally. Nevertheless he was able to welcome the delegates and to hold his inaugural address via video live stream. Regarding the technological development of the cement industry, one of the main challenges for the future perspective will be the limited materials. To help cope with the future challenges he confirmed the support of the Ministry of Commerce and Industry.
In this work, we synthesized and characterized mesoporous thin fims
of SiO 2 and NiTiO3 structured by a surfactant called Brij58. These fims
were fabricated by the method of dip coating and the best conditions for
well-structured thin fims were investigated as a function of surfactant
concentration and diffrent types of substrates. These fims have been
characterized by X-ray reflctivity which was calculated using the matrix
formalism. We demonstrated that the silicon substrate had a great effct
on the structure and porosity of the fabricated fims for both SiO2 and
NiTiO3. Furthermore, we found that mesoporosity has been increased
as a function of the surfactant concentration in the solution. This experimental procedure allows also to produce NiTiO3 powders which have
been characterized by X-ray diffaction. The XRD coupled to the crystallographic software “Maud”shows that the samples are constituted by 98,
2% NiTiO 3 powders.
Developments of nano clay particle reinforced plastics are of growing interest towards the
emergence of new materials which enhance optimal utilization of natural resources and particularly of
renewable resources. The effects of nano clay as filler in Basalt–epoxy composite systems on the
tribological properties have been discussed in this article. Basalt fiber reinforced epoxy (BE) composite
finds widespread application in erosive environment due to its several advantages like high wear
resistance, high strength-to-weight ratio and low cost. Experiments were carried out to study the effects
of impingement angle, particle velocity and filler material on the solid particle erosive wear behavior of
BE composite. The erosive wear is evaluated at different impingement angles from 30° to 90° at three
different velocities of 23, 42, & 60 m/s. The erodent used is silica sand with the size range (150 – 280 µm)
of irregular shape. The result shows semi-ductile behavior with maximum erosion rate at 60°
impingement angle. It is observed that wear rate increases with increasing particle velocity and
decreases with increases of filler percentage. The morphology of the eroded surfaces was examined by
using Scanning electron microscopy (SEM).
Viscoelastic response of polymeric solids in sliding contactspadmanabhankrishnan4
Abstract: The viscoelastic response of polymeric solids to sliding contact conditions
is observed and analyzed with respect to the sliding speed, material composition,
and geometry. It was discovered that polymeric solids produced their own distinct
viscoelastic signatures that cause resonance at certain sliding speeds which can be
explained with resonance conditions for electromagnetic waves. The observed viscolelastic phenomenon is characterized with respect to the relaxation and recovery
times for rigid polymeric solids. It is confirmatory as a demonstration of proof of
existence of viscoelasticity and self-organization in these materials under sliding contact conditions. Viscoelastic observations are also made on the aged specimens in
sliding contact.
Fabrication and Mechanical Charecterization of Cnt NanocompositesIOSR Journals
The effects of Amine, Epoxide functionalization of multi-wall carbon nanotubes on properties of CNT/epoxy nanocomposites are investigated in this work. Adding CNTs to the matrix is expected to improve the stiffness, toughness, interlaminar shear strength of and many other properties of composites. Functionalization with different amino and epoxide groups of multi-walled carbon nanotubes was achieved and nanotube-reinforced epoxy nanocomposites were prepared by mixing amino, epoxide-functionalized multi-walled carbon nanotubes with epoxy resin. The reinforcement mechanism of amino-functionalized multi-walled carbon nanotubes in epoxy resin was discussed. Interlaminar shear strength (ILSS), Three point bending test and Re-bound hardness tests were used to investigate the mechanical properties of the nanocomposites and functionalization groupings are investigated by Fourier transform spectroscopy (FTIR). Then the results of amine, epoxide group are compared with No-CNT nanocomposite. The results showed that different percentage of amino, epoxide -functionalized multi-walled carbon nanotubes would have different effects on the mechanical properties of the nanocomposites. The amine functionalizes CNT composites are giving good results compare to another samples
Role of Natural and Synthetic Fillers on Erosive Wear Behavior of Basalt -Epo...IJRES Journal
An investigation was made to evaluate the effect of the incorporation of bio-based jatropha oil cake (JOC), Titanium dioxide (TiO2) and Clay on the erosive wear behavior of Basalt-epoxy (BE) hybrid composites. A Vacuum-Assisted Resin Infusion (VARI) technique was employed to obtain a filled and unfilled B-E composites. The effect of different impact velocities (20 and 40 m/s) and angle of impingement from 300 to 900 on the performance of the wear resistance of the composites were measured. The results of erosive wear losses, angle of impingement, and impact velocity and erosion rate of 3% of TiO2 and JOC filled and unfilled B-E composites are analyzed and discussed. The worn surface features of unfilled and filled B-E composites were examined using Scanning Electron Microscopy (SEM).
Water Absorption, Thickness Swelling and Rheological Properties of Agro Fiber...iosrjce
IOSR Journal of Polymer and Textile Engineering (IOSR-JPTE) is ambitious to disseminate information and experience in education, practice and investigation between polimer, fibric and all the sciences involved in textile.
Investigation on The Mechanical Properties of Banana Fiber Reinforced Polyest...IJERA Editor
the interest in natural fiber-reinforced polymer composite materials is rapidly growing both in terms of their industrial applications and fundamental research. The natural fiber composites are more environmentally friendly, and their availability, renewability, low density, and price as well as satisfactory mechanical properties make them an attractive ecological alternative to glass, carbon and man-made fibers used for the manufacturing of composites. The main objective of this project is to investigate the effect of NaOH solution on the mechanical properties of Banana fiber in polyester composites. The composites have been made by with and without treatment of NaOH solution using polymer matrix using Banana fiber. Mechanical properties such as tensile, impact and bending strengths were Studied by Carrying out respective tests with varying weights of fiber (0.5, 1, 1.5 and 2 gm’s). The tensile, impact and bending Strength of Banana fiber reinforced composites with NaOH solution was found to be increased when compared with without NaOH solution by varying fiber content. The concentrated of NaOH solution (5%) to water (for 1lit).
Rear Bumper Laminated In Jute Fiber With Polyester Resin.IJERA Editor
Today, a growing interest exists in the use of natural of fibers (sisal, coconut, banana, and jute), as
reinforcement in composites. The aim of the present study is shows the use of jute fiber agglutinated with
polyester resin in the automobile industry in the production of a rear bumper of hatch vehicle. A simplified
mathematical model was used for evaluation of the flaw on trunk center cover submitted to dynamic loads. The
traverse section of the referred bumper is simplified by a channel formation. This study shows that a rear
bumper made using jute fiber agglutinated with polyester resin will be possible. The molded part obtained good
visual characteristics, good geometric construction and surface without bubbles and imperfections in the fiber
and resin composite. The mathematical model to failure criterion showed that the rear bumper in jute fiber will
not resist to an impact equivalent at 4.0 km/h.
A STUDY ON TENSILE AND COMPRESSIVE STRENGTH OF HYBRID POLYMER COMPOSITE MATER...IAEME Publication
Hybrid composite Materials have extensive engineering application where strength to weight ratio, low cost and ease of fabrication are required. Hybrid composites provide combination of properties such as tensile modulus, compressive strength and impact strength which cannot be
realized in composite materials.
Similar to A solvent swelling method to visualize rubber particles network in biodegraded household natural (20)
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A solvent swelling method to visualize rubber particles network in biodegraded household natural
1. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.3, 2014
1
A Solvent-swelling method to visualize rubber particles network
in biodegraded household Natural Rubber (NR) latex gloves
Shamsul Bahri A.R.
Microscopy Research group,
Faculty of Agro-technology and Food Science,
Universiti Malaysia Terengganu,
21030, K. Terengganu,
Terengganu, Malaysia
E-mail: shamsul@umt.edu.my
Abstract
The environmental degradation of household NR latex gloves buried in soil was examined using Transmission
and Scanning electron microscope. Gloves pieces were treated with acetone to remove the autooxidation
formulation prior to soil burial and compared with the untreated gloves. All gloves had been allowed to degrade
for various time periods (3, 12, and 18 months). Degradation degree of the samples was evaluated on the
integrity of rubber network of the latex particles within the samples using electron microscope. Prior to
observation under microscope, samples were prepared using a solvent-swelling method. There were marked
differences between network densities of latex particles for treated and untreated samples as early as 3 month
treatment. Latex particles in treated samples showed a very coarse and loose rubber network that occasionally
surrounded by a network of higher density latex particles, though a few remnants of latex particles can still be
seen. Whereas the untreated samples showed some distinguished latex particles membrane and the integrity of
rubber network was still intact. The disintegration of rubber network became more apparent in 12 and 18
months of burial. Rubber particles network in 18 months samples disintegrated totally, and the network
coalesced into free polymeric strands. Solvent-swelling method gives a clearer picture on rubber particle
network.
Key words: solvent-swelling method, latex biodegradation, rubber particle network, household NR latex.
Introduction
Generally the environmental degradation of carbon-chain polymers uses both abiotic and biotic chemistry to
return the products of oxo-degradation to the biological carbon cycle (Scott, 1997, 2000, 2002; Billingham et al.,
2002). Although natural rubber (NR) is a polymer “made in nature” with environmental advantages, thick latex
film products appear to be bio-resistant because they take longer time to break down naturally after being
discarded in waste management infrastructures. Conversely, thin latex products such as examination and
surgical gloves are capable to degrade within a realistic time scale. Bacteria, fungi and the mycelium-forming
actinomycetes degrade vulcanised NR products but microbial rubber degradation alone can be a very slow
process (Rose and Steinbuchel, 2005; Shah et. al., 2013; Imai et. al. 2011).
The application of electron microscopy to study degradation process of NR latex is preferred for its high
resolution and resolving power. Conventional transmission electron microscopy (TEM) is an imaging technique
whereby a beam of electrons is transmitted through a thin specimen, then an image is formed, magnified and
directed to appear either on a fluorescent screen or on layer of photographic film for viewing or to be detected by
a sensor such as CCD camera for image capturing and digital archiving. Ultrathin section of polymer samples
(up to 130µm in thickness) is normally required in order for the beam to penetrate and formed the image.
Routine in-house method to visualize polymer ultrastructure using a TEM requires samples to be cryosectioned
with a cryo-ultramictrotome, contrasted with heavy metals and visualized the sections using a TEM. However,
this technique provide limited information on the interaction between the matrixes (i.e. rubber) with other
components (i.e. fillers) A solvent-swelling method by mixing and polymerized styrene with NR latex films
offers an alternative toward visualizing the rubber particle network and its inter-relation with other components.
This paper describes initial work using the solvent-swelling procedure on degraded NR latex gloves and
visualized using a TEM in an attempt to have a better understanding on the microstructure of degrading rubber
particles in NR latex films.
2. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.3, 2014
2
Materials and Methods
Polymer swelling procedure
The film pieces were retrieved from soils at 3, 6, 12 and 18 months after burial, and four replicates of each
treatment were sampled at each sampling time. All polymer samples were styrene-swelled using the protocol as
follows. Small pieces of degraded NR latex gloves were cut into small pieces (1x5 cm) and wrapped with lenses
tissue. The samples were then put in a Soxhlet extraction apparatus and extracted in a refluxing acetone
overnight. This was to get rid of any impurities (primarily sulphur or antioxidant) that could hinder
polymerization process later on. After the extraction was completed, the samples were allowed to dry off to
remove residual solvent. The samples were then immersed in a styrene solution (1 wt. % Benzoyl Peroxide, 2 wt.
% Dibutyl Phthalate plasticizer) and allowed to swell in the solution for 1 – 2 days. The swollen latex strips were
then cut into smaller pieces of 10 x 2 mm strips and transfer into gelatin capsule and top up the capsules with
fresh styrene solution. The capsule caps were pressed firmly and labeled accordingly. The capsules were put in a
sample holder and heated at 68°C in an oil bath and leaved the styrene to polymerize at least overnight. When
the styrene has hardened fully, the harden block were proceed to the next step which was sectioning using an
ultramicrotome.
Sectioning of polymer with cryoultramicrotomy
The styrene blocks were sectioned using a cryo-ultramicrotome (LKB MT-7000 ultramicrotome and CR-21
cryo-unit), with the temperature set at -110°C for the chamber, knives and the specimen. Ultrathin sections
(100nm thickness, cutting speed 2mm/s) were deposited onto an uncoated copper grid (applied slightly with
propanol to relax the sections and to ease the manipulation of the cryosections) in a cryo-chamber. The grids
were then stained with osmium tetroxide for 1 hr in a fume cupboard. The sections were then viewed with a
TEM (Philips CM12) and micrographs were recorded.
Results and Discussion
Polymer microscopy has evolved so much recently in sample preparation especially for Transmission electron
microscopy (TEM) observation. The current TEM setup which was routinely used for examining blend
morphology and phase structure, swollen networks, thin films, replicas and particles has endless capability in
adapting with the changes on the sample preparation methodology. Our routine in-house polymer methodology
required the sample to be subjected to sub-frozen condition during sectioning and viewing the thawed sections
with the TEM. This method however offered limited information on the interaction between polymer matrixes.
As an example, there was hardly anything resembling a rubber particle that can be seen from the micrograph
(Figure 1a) . Rubber phase was observed as gray background (unstained) and electron dense sheet and dark
agglomerates were the filler. In contrast with the same sample that was styrene swelled, the demarcation of
rubber particles and its network was very obvious (contrasted with osmium tetroxide) (figure 1b).
Figure 1: TEM micrographs of PVA latex with montmorillonite (MMT). Unswollen samples (a), styrene-
swelled sample (b). Arrows indicate the fillers (MMT)
3. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.3, 2014
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This technique was then applied to the degraded NR latex gloves to see the degree of rubber particles
disintegration, the effect that was reported caused by the soil microfloras (Ikram et al., 2001; Scott, 1997; Ismail
et. al., 2013). In styrene-swelled samples, rubber particles which has been stained with osmium tetroxide
appeared electron dense as compared to the clear and lighter (unstained) area which are mainly polystyrene.
This observation was due to a polystyrene phase that was created which was immiscible with the rubber during
polymerization. Thus a phase separation occurs in which rubber chains were forced together between the
growing domains of polystyrene, resulting in a mesh structure of rubber threads that was visible under the
electron microscope 3
.
Figure 2 showed NR gloves that were buried in the soil for 3 months. The micrographs of degraded glove
(untreated samples) showed latex particles as a homogenous network structure, entangled with each other. There
were areas where the latex particles stained darker than the others. It was probably due to the difference in
particle density or different level at which the particles was sliced during sectioning. If the section was close to
the rubber membrane, which normally comprised of lipid bi-layer, that area will stain more with osmium.
Treated degraded glove (T – 3 month) showed a less prominent shape and disorganized mesh structure of rubber
particles, with rubber network loosely orientated (figure 2b). Voids or polystyrene areas were more prominent as
compared to the untreated samples. This inhomogeneous nature of the rubber crosslinking in treated glove,
probably could be explained by the dissolution or rubber chain breakdown by microbial activities.
Figure 2 : TEM micrographs of 3 months-degraded NR gloves. Darker area is a matrix of rubber particle in a
polystyrene background (grayish colour). Rubber particles are still intact in untreated sample with clear
demarcation of individual particles (a). Small degree of rubber particle breakdown can be seen in treated sample
(b).
The rubber network between the three and twelve months-untreated sample was quite similar and not much
difference in their particle integrity as shown in figure 1a and 2a. However it was very clear the disintegration of
rubber particles were more apparent in the treated NR gloves. It was hardly any delineation of any individual
rubber particles observed. The rubber particles appeared as a mass of entangled network, interweaving with each
other in the gray matrix of polystyrene (figure 3b).
4. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.3, 2014
4
Figure 3: TEM micrographs of 12 months-degraded NR latex glove. Untreated NR latex glove shows extended
degree of rubber particle disintegration. Some particles appear darker than the others, especially the smaller
particles. Total dissolution of rubber particles in treated gloves is evidence at this stage (b). Some inclusion of
microorganism can be seen in the rubber mass (arrows).
Figure 4: TEM micrographs of 18months-degraded NR latex gloves. A complete breakdown of rubber particles
for both untreated (a) and treated (b) NR gloves.
Figure 4 of 18months-degraded gloves showed a total breakdown of rubber particles. Rubber networks became
sparse in intensity and loose rubber strands mixed and blend with the polystyrene with the later has a higher
concentration ratio especially in the treated sample (figure 4b). There was hardly any remnant of microorganism
inclusion in the rubber matrixes as compared to the unswollen sample (Figure 5 & 6). This probably due to the
rigorous process particularly during extraction steps, which removed some traces of microorganism in the rubber
matrixes.
5. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.3, 2014
5
Figure 5: TEM micrographs of 12 months-degraded NR latex gloves. Unswollen sample. Dark inclusions in the
gray rubber matrix are remnant of fungi bodies that penetrate into the interior of the NR latex film (arrows).
These observations are very prominent in unswollen sample as compared to the styrene-swelled samples.
Figure 6: A Scanning Electron microscopy (SEM) image of microflora that resides on the surface of the
degraded NR latex Gloves (arrows). A crack on the surface of the glove is also an evidence of degradation in
process.
Conclusion
Rubber particle’s network in degraded NR latex films was clearly demonstrated using this styrene-swelling
method. Rubber network disintegrated and clearly broke down when kept longer in the soil. The surface
colonizing microorganisms may not reflect the true population densities associated with the degrading material,
since much of it could have penetrated into the decaying pieces and were not liberated into the extraction media
unless the pieces were blended
6. Journal of Natural Sciences Research www.iiste.org
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.4, No.3, 2014
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Acknowledgements
The author thanks staffs at Material Characterizatin Unit of Tun Abdul Razak Research Center, Brickendonbury,
UK for capable research assistance and Dr. S. Cook for suggestions in the preparation of this manuscript. The
author also acknowledges contribution by Dr. Ahmad Ikram from the Rubber Research Institute of Malaysia for
supplying the latex samples. This research was funded by Fundamental Research Grant Scheme
(FRGS/1/2013/ST03/UMT/02/01)
References
Ikram, A., Shamsul Bahri, A.R., Fauzi, M.S. and Napi, N. (2001) Effects of added Nitrogen and Phosphorus on
the Biodegradation of NR gloves in soil. Journal of Rubber Research, 4. 102 – 117.
Ikram, A., Ma’azam, M.S., Amir Hashim, M.Y., Fauzi, M.S., Shamsul Bahri, A.R. and Kamaruzaman, S.
(2005) Effect of Antioxidants and Latex Vulcanising Agents on the Environmental Degradation of Latex Films.
Journal of Rubber Research. 8(4), 220-240.
Imai, S., Ichikawa, K., Muramatsu, Y., Kasai. D., Masai, E. and Fukuda, M. (2011) Isolation and
characterization of Streptomyces, Actinoplanes, and Methulibium strains that are involved in degradation of
natural rubber and synthetic poly(cis1,4-isoprene). Enzyme and Microbial Technology 49. 562-531.
Ismail M.A., Mohamed H.N and Soreit A.A.M (2013) Degradation of Ficus elastica rubber latex by Aspergillus
terreus, Aspergillus flavus and Myceliopthora thermophile. International Biodeterioration & Biodegradation 78.
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