Publication: Thermal, mechanical and biodegradation characteristics of poly(butylene adipate-co-terephthalate) composite for mulch film application
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Date
2024-08-01
Authors
Maisara Azad, Mat Akhir
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Abstract
The extensive use of polyethylene (PE) mulch film has negatively impacted
the environment due to carbon dioxide emissions and its slow degradation property.
Research indicates that PE takes about 100 years to fully decompose.
Biodegradable polymer mulch films, designed for in situ biodegradation, have
garnered global attention as a solution to this environmental issue. The present
study aims to develop biodegradable polymeric mulch films based on Poly(butylene
adipate-co-terephthalate) (PBAT) biocomposites for crop protection. PBAT
blended with 10 to 50 wt% thermoplastic starch (TPS) was prepared via melt
blending technique and characterized for mechanical, thermal, and water barrier
properties suitable for mulching. Sugarcane bagasse (SB) fibers (5 to 20 wt%),
untreated and treated with (3-Glycidyloxypropyl)trimethoxysilane (GPTMS) and
alkaline were incorporated into the PBAT/TPS(90/10) optimized blend. Results
obtained from the study were compared with the soil biodegradable mulch films
standard, EN17033. Next, the protective additives, including hindered amine light
stabilizer (HALS), carbon black (CB), and anti-hydrolysis agent (AH), 0 to 2wt%
were incorporated into the formulation to mitigate photodegradation and
biodegradation. Lastly, the formulations were optimized using the design of
experiment (DOE), fabricated for mulching films, and applied in the pak choy
cultivation plant pots. The temperature change, crops’ yield, and film
biodegradation were evaluated. From the findings, the optimal composition for the PBAT/TPS blend is PBAT/TPS(90/10), exhibiting high tensile strength (23.87
MPa) and elongation at break (1135.69%). In the second part of the study, the
results showed that 5% of treated SB in PBAT/TPS(90/10) showed adequate tensile
strength (13.5 MPa), elongation (739.5%), thermal stability (up to 280 °C), good
water barrier property (less than 9% water absorption after 76 hrs), and is having
hydrophobic property compared to the EN17033. Surface treatments increased SB
biocomposite's tensile strength and flexibility by 6 to 15%. DOE analysis indicated
that all additives preserved tensile properties and reduced degradation, with AH
showing the highest contribution which is more than 32.8% contribution under
natural weathering, more than 57.3% under soil burial, and more than 26.9% under
artificial accelerated weathering conditions. Lastly, the applied formulated
mulching films increased up to 0 – 2℃ soil temperature at a depth of 10 cm than
no mulch, maintained 35 to 38% higher soil moisture levels than PE mulch,
excellent weed control, and comparable crop yields to PE and commercialized
biodegradable mulch. Additives added in the formulation protected the films,
ensuring durability and self-biodegradation throughout the cultivation season.
Overall, this study demonstrates the successful fabrication of biodegradable
mulching film based on PBAT for crop protection.