Studies on the Degradation of Polyethylene /Banyan Dry Leaves

Studies on the Degradation of Polyethylene /Banyan Dry Leaves

Article Type: Article

Authors: A. U. Santhos Kumar and N. Jaya Chitra

Abstract: The banyan dry leaves powder in the present research were incorporated into LDPE, LDPE in about 5 wt% subsequently processed to produce films of 50μ thickness. The bio-based additive such as Banyan  dry leaves powder were successfully mixed and their performance on the photo and biodegradability of polyethylene films were studied under the influence of accelerated UV/sunlight.  The percentage of biodegradation of the photodegraded film was analyzed by ASTMD 5338-98. The photodegraded film was subjected to biodegradation is 30%.

Address: Department of Chemical Engineering, Dr. MGR Educational Research Institute University, Chennai-95   Corresponding author Email: santhosannauniv@gmail.com

Keywords: LDPE; Biodegradation; Photooxidation; Banyan dry leaves powder

Introduction

Plastics waste management remains a major environmental issue due to over population and rapid economic development. The complete degradation of plastics mainly polyethylene remains a challenge and the current work is focused on enhancing the biodegradation of polyethylene.  The photo degradation followed by biodegradation of PE could be enhanced by the use of bio-based additives [1-26].

Experiment

Material and methods

General purpose film grade LDPE has been used to prepare films. Banyan dry leaves powder were used

Blending and film preparation of LDPE

The Banyan dry leaves powder was melt blended with LDPE at three different formulations 1, 3 & 5% respectively in (Haake, Rheomex OS, PTW16, Thermo scientific, Germany) Modular Torque Rheometer.  The Modular Torque Rheometer blending was carried out at temperature range of   100-190 °C (from die to hopper) & a screw speed of 100 rpm.  Subsequently, the pellets are dried in a dehumidifier at 70°C for two hours to remove moisture.  The pellets produced were subsequently dried & subjected to film cast process to produce films of 50 µ thicknesses.

Photodegradation

All blended samples were subjected to photodegradation studies using QUV UV Weather-o-meter.

Titration method of CO2 determined test (ASTM D 5338)

The details of the biodegradation experiment are summarized below;

Sample detail

Before and after brittle fragmented photodegraded LDPE -Banyan dry leave powder

Conditions of reaction mixtures

Origin of compost                                     : Municipal and vegetable waste

Reaction Temperature                                 : 58o C

Dry Solid (%)                                                : 52%

Volatile Solid (%)                                        : 20

Air flow rate                                                  : 100 ml/min

Test duration (day)                                      : 90 days

PH                                                               : 7.4

Reference material                                      : Cellulose

Volume of reaction vessel                          : 3000 ml

The preparation and ageing of the compost for biodegradation of film samples was carried out as per the standard. The PH value for all the samples, control and blank was maintained. Barium Hydroxide solution (0.024 N) was prepared by dissolving 4.0 g of anhydrous barium hydroxide in 1000ml of distilled water. The solution was filtered and the normality was determined by titrating against standard acid solution and stored in a sealed container as a clear solution to prevent absorption of CO2 from air. About 5-20 L of 0.024 N barium hydroxide solutions was prepared at a time for running a series of tests. However, care was taken that a film of BaCO3 does not form on the surface of the solution in the glass vessels, which would inhibit CO2 diffusion into the absorbing medium.

Procedure

The composting vessels were incubated in diffuse light minimum for a period of 90 days & the temperature of the system was maintained at 58±2 °C. The CO2 & O2 concentrations were checked in the outgoing air daily with a minimum time interval of 6 hrs after the first week. The air flow was adjusted to maintain a CO2 concentration of at least 2% volume to allow accurate determination of CO2 level in the exhaust air. Composting vessels were shaken weekly to prevent extensive channeling which could provide uniform attack of microbes on test specimen and provide an even distribution of moisture. The incubation time was fixed for 90 days.

Fig. 1 The percentage of biodegradation of LDPE with 5% ADGN additives as per ASTM D 5338  

Figure 1: The percentage of biodegradation of LDPE with 5% ADGN  additives as per ASTM D 5338

 

Carbon dioxide analysis

The carbon dioxide (CO2) produced in each vessel reacted with Ba(OH)2 and was precipitated as barium carbonate (BaCO3).  The amount of carbon dioxide produced was determined by titrating the remaining barium hydroxide with 0.05 N hydrochloric acid to a phenolphthalein end point. Because of the static incubation, the barium carbonate built up on the surface of the liquid was broken up periodically by shaking the vessel gently to

ensure continued absorption of the evolved carbon dioxide. The hydroxide traps were removed and titrated before their capacity exceed. At the time of removal of the traps, the vessel was weighed to monitor moisture loss from the soil and allowed to sit open so that the air was refreshed before replacing fresh barium hydroxide and releasing the vessel. The carbon dioxide evolution rate reaches a plateau when all of the accessible carbon is oxidized. The test was terminated at this point. At the conclusion of the test, the pH and moisture and ash content of the soil is measured and recorded.

Result and Discussion

Biodegradation of the LDPE with Banyan dry leave powder

As shown in Figure 1 conditions of reaction mixtures: Organ of compost; livestock excrement, municipal and Vegetable waste used the method used for the determination of the biodegradability of the LDPE was based on the International Standard (ASTM D 5338-98) that measures the evolved CO2 amount from both the blank vessel without a sample and the sample vessel including a 10 g LDPE –Banyan dry leaves powder samples.  According to ASTM D 5338 test procedure. Fragments occur progressively in the biodegradation of the photodegradaded films. Moreover, the biodegradation test results reveals that the LDPE-Banyan dry leaves powder additives shows 30% of biodegradation on photo degraded LDPE films when observed at the end of 90 days.

Conclusion

LDPE- Banyan dry leave powder shows improvement in photodegradation rates.  After the photo degradation subjected to biodegradation, the percentage of biodegradation was 30% at the end of 90 days as per ASTM D 5338.

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