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									    INTERNATIONAL JOURNAL OF ADVANCED RESEARCH 0976
International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN IN –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 6, September – October (2013), © IAEME
               ENGINEERING AND TECHNOLOGY (IJARET)

ISSN 0976 - 6480 (Print)
                                                                          IJARET
ISSN 0976 - 6499 (Online)
Volume 4, Issue 6, September – October 2013, pp. 50-56
© IAEME: www.iaeme.com/ijaret.asp                                         ©IAEME
Journal Impact Factor (2013): 5.8376 (Calculated by GISI)
www.jifactor.com




    STUDY OF DEGRADATION OF SYNTHETIC POLYMER NYLON 6 BY
                    COMPOSTING METHOD

             Chonde Sonal G1, Pawar Nilambari R1, Chonde Sachin G2, Raut P. D1
        Department of Environmental Science, Shivaji University, Kolhapur- 416 004. INDIA,
                                   AMGOI, Vathar, Kolhapur



ABSTRACT

         Nylon is a generic designation for a family of synthetic polymers known as polyamides. This
tends to give polymers useful properties such as flexibility and elasticity. Because of durability and
visibility of polyamides hazards of discarding polyamides is called as ‘White Pollution’. Present
study has examined the feasibility of composting for actively degrading Synthetic Polymer Nylon 6.
For present experiment, Nylon 6 sheets were submerged in semi natural environment carried in
Borosil glass for specific duration of 3 months to observe degradation. Physiochemical Analysis of
compost was carried out for concentration of organic carbon, Potassium, Phosphorous and Electrical
conductivity. Nylon 6 sheets were analyzed for degradation study which was monitor by weight
reduction, thickness reduction; chemical analysis etc. composting conditions degrade the polymer
which is confirmed by 10% weight loss, 13% thickness reduction and weakening in amide bond in
polymer.

Keywords: biodegradation, composting study, Nylon 6

INTRODUCTION

        Plastics are made up of long chain molecules called polymers. Polymers are made when
naturally occurring substances such as coal, natural gas and oil are transformed into other substances
with completely different properties. Polyamide is a polymer, which contains recurring amide groups
(R-CO-NH-R') as integral part of the main polymer chain. Synthetic polyamides are produced by a
condensation reaction between monomers, in which the linkage of the molecules occurs through the
formation of the amide groups [1]. Biodegradation of polyamides is chemical changes by changes in
bands like stretching, weakening etc., by microorganisms. Polymeric materials are not easily
biodegraded. Efforts have been directed to develop mild physicochemical procedures, which

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International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 6, September – October (2013), © IAEME

includes thermal and radiation pre-treatments to enhance the biodegradation process [2]. Degradation
is the process in which a product is capable of being chemically degraded, changing its mechanical
and chemical properties. A product is degradable when it can change its properties in a time scale
due to the action of heat, light or mechanical stress. Any physical or chemical change in polymer as a
result of environmental factors, such as light, heat, moisture, chemical conditions or biological
activity is termed as degradation of plastics.
        Polymeric materials are not easily biodegraded. Efforts have been directed to develop mild
physico-chemical procedures which include thermal and radiation pretreatments to enhance the
biodegradation process (Albertson et al., 1987). The degradation of plastics in nature is a very slow
process which is first initiated by environmental factors followed by wild micro-organisms. The
environmental factors include temperature, humidity, pH and UV. Biodegradation is the ability of
micro-organism to influence abiotic degradation through physical, chemical or enzymatic action [2]
[3] [4] [5]. Interplay between biodegradation and different factors in the biotic and abiotic
environments are very important. The micro-organism reported for the biodegradation of the
polyethylene include fungi (Aspergillus niger, Aspergillus flavus, Aspergillus oryzae, Chaetomium
globusum, Penicillium funiculosum, Pullularia pullulan), bacteria (Pseudomonas aeruginosa,
Bacillus cereus, Coryneformes bacterium, Bacillus sp., Mycobacterium, Nocardia, Corynebacterium,
Candida and Pseudomonas) and Actinomycetales, Streptomycetaceae. Their activity on the polymer
was studied by growth tests on solid agar medium for a definite period of time. The changes in
molecular weight, structure, crystalinity, density, weight loss, mechanical, optical or dielectric
properties, etc., were also measured [6] [7] [8] [9] [10]. Unlike polypropylene, more research articles
are published on studies relating to biodegradation of polyethylene. Fungi that include A. niger,
Penicillium funiculosum, Fusarium redolens and A. vesicolor, and soil microorganisms (mixed
culture as well as Rhodococcus rhodochorus, Cladosporium cladosporoides) have been reported to
degrade polyethylene [2].
        Plastics are biodegraded aerobically in wild nature, anaerobically in sediments and landfills
and partly aerobically and partly anaerobically in compost and soil. Carbon dioxide and water are
produced during aerobic biodegradation and carbon dioxide, water and methane are produced during
anaerobic biodegradation. Some basic composting methods which have been developed for
degradation of plastic.

MATERIALS AND METHODS

Materials
      Polymer Nylon 6 was purchased from Sigma Aldrich Company. Sheets of Nylon 6 are
exposed for composting conditions. For Compost preparation kitchen waste, cow dung, are used.

Disinfection of the sample
       The sample sheets were sterilized before they were inoculated into the composting condition.
The nylon 6 sheets were dipped in 1 % hypochlorite for a few hours. Washed with distilled water
thoroughly in order to remove all the hypochlorite and later dried. No physical or chemical changes
were observed in the sample after hypochlorite treatment.

Biodegradation of Nylon 6 sheet under Semi-Natural Environment Composting
       Biodegradation of Nylon 6 was carried out by keeping the sheets under semi- natural
conditions of environment that is composting. Semi- natural is word used to describe the laboratory
conditions. Its in-vitro composting method for degradation of polyamides. But in this semi-natural
method composting was carried in Borosil glass tray. Composition of composting in which

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International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 6, September – October (2013), © IAEME

concentration of manure and soil as 1:3 ratios. Green and brown leaves, waste as carbon source,
moisture condition moderately maintained. In semi-natural composting, special type of tray is used
which is made up of Borosil (glass) named as “Square Cake Dish” (small). Usually, for composting,
plastic large trays are used but in semi-natural composting, glass trays are used which is kept in
laboratory under aerobic conditions. Sheets of polyamide under composting condition were kept for
about 3 months for completion of compost. Different composting parameters are checked as pH,
organic carbon, Phosphorous, potassium, electrical conductivity etc. nylon 6 sheets are observed for
biodegradation for weight reduction, thickness reduction, chemical analysis by I. R. Spectroscopy.
Morphological changes were monitor by inverted microscope. Also thermal analysis of plastic was
checked by TGA analysis.

RESULTS AND DISCUSSION

       Degradation of Nylon 6 sheets in semi natural composting condition was observed for 90
days. Results presented in the following sections were obtained from two independent sets of
degradation experiments.

             Table no.1 Compost parameters observed during 90 days for Nylon 6.
 Sr. Inoculated      pH Temperature        organic    phosphorus     potassium       electrical
 No. with Nylon                            carbon        oxide                      conductivity
          6                                                                           (µm/cm)

  1      Before      7.7       250C         0.678       256.655        1572.48          0.92
       composting

  2      After       8.2       290C         1.002       211.876        1451.52          1.08
       composting



 Table no. 2Percentage (%) Weight loss observed in Nylon 6 sheets during composting study

                       Sr. Time Duration % Weigh reduction of sheets
                       No.                of nylon 6 in composting
                                                  condition

                           1     0 Days                      0

                           2     1 month                     2

                           3     2 month                     6

                           4     3 month                    10




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International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 6, September – October (2013), © IAEME

 Graph no. 2Percentage (%) Weight loss observed in Nylon 6 sheets during composting study

                             % Weigh reduction of sheets of
                             nylon 6 in composting condition
                   12
                   10
                    8
                    6                                              % Weigh reduction of
                                                                   sheets of nylon 6 in
                    4
                                                                   composting condition
                    2
                    0
                                0 Days 1 month 2 month 3 month




Table No. 3 Percentage (%) thickness reduction observed in Nylon 6 sheets during composting
                                           study

                    Sr.        Time Duration            % thickness reduction of
                    No.                                    Nylon 6 sheets in
                                                         composting condition

                         1         0 Days                             0

                         2        1 month                             6

                         3        2 month                            10

                         4        3 month                            13

Graph No. 3 Percentage (%) thickness reduction observed in Nylon 6 sheets during composting
                                          study

                             % thickness reduction of Nylon 6
                              sheets in composting condition
                    14
                    12
                    10
                     8
                                                                 % thickness reduction of
                     6                                           Nylon 6 sheets in
                     4                                           composting condition
                     2
                     0
                               0 Days 1 month 2 month 3 month




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International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 6, September – October (2013), © IAEME

Chemical study of Nylon 6 sheet

Fourier Transformed Spectroscopy Study of Nylon 6

                              FTIR Spectra of Nylon 6 sheet (Control)




                FTIR Spectra of Nylon 6 sheet (expose to composting conditions)




       Table No. 4 Thermo gravimetric study of Nylon 6 sheet treated with composting
             Sample                     Temperature oC Corresponding to weight loss

                                  10% 20% 30% 40% 50% 60% 70% 80% 90%

        Nylon 6 (Control)         413    437    448    457    461       469   476   482   -

      Nylon 6 treated with        412    435    445    456    459       467   474   480   -
      composting condition




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International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 6, September – October (2013), © IAEME

Morphological changes observed in Nylon 6 Sheet




                                        Nylon 6 (Control)




                        Nylon 6 sheet treated with composting condition


RESULTS AND DISCUSSION

Composting parameters observed
        The compost which was prepared from kitchen waste material shows increase in some
parameters as Temperature, pH, organic carbon, electrical conductivity etc. the compost prepared
was show high nutrient content due to organic carbon. As the carbon content was increase up to 1.02
mg/l. the conductivity was also found to be increased up to 1.08 µm/cm. (Table no 1).

Degradation of nylon 6 sheets
        Present study was related with the study of biodegradation of nylon 6 under composting
conditions. The study was carried out under composting conditions. In case of nylon 6, the physical
parameter such as weight and thickness was observed to be reduced to some extent. It was observed
that the weight loss was observed up to 10% (Graph 1) and thickness of sheets was reduced up to
13%.(Graph 2). Chemical analysis by using FTIR shows the weakening in the amide bonds. The
strength of characteristic bands of C (O) NH occurring around 3300, 1640, 1550 and 1018 cm-1
decreased after composting. There may be formation of new groups like CH3, CONH2, CHO and
COOH, may be formed due to hydrolysis and oxidation [11]. The thermo gravimetric results explain
the thermal stability of nylon polymer. At control condition the polymer was found to be stable and
show 80% degradation at 482oC, while the nylon 6 sheets treated at composting condition shows
30% weight loss at 445oC, 60% weight loss at 467oC and 80% weight loss at 480oC temperature.
(Table no.4) This indicates the decrease in temperature for the degradation, which indicates the
degradation of polymer. The morphological study shows change in colour of nylon 6 sheet as it
changes to brown color and smoothness of sheets are changes to rough surface area of sheet.



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International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 4, Issue 6, September – October (2013), © IAEME

CONCLUSION

       Present study was related with the biodegradation of nylon 6 polymers at composting
condition. The study concludes that the polymer nylon 6 which is found to be hard for degradation
degraded partially in composting process. The microorganisms which are present in compost play
important role in degradation of polymer.as the degradation was observed by 10% weight loss and
13% thickness reduction. Chemical characterization also explains the weakening in amide bond
while the TGA study shows that the polymer has lost thermal stability due to degradation.
Composting is found to be very good method for biodegradation of polymer. It takes more time to
degrade the polymer as it is combined action of microorganisms.

ACKNOWLEDGMENT

       Authors are thankful to authorities of Shivaji University, Kolhapur and Department of
Environmental Science, Shivaji University, Kolhapur and Department of CFC Shivaji University,
Kolhapur for providing facilities to carry out work. Authors are also thankful to Sigma Aldrich for
providing Nylon 6 polymer.

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