A Degradable Inverse Vulcanized Copolymer as a Coating Material for Urea Produced under Optimized Conditions

Ali Shaan Manzoor Ghumman; Rashid Shamsuddin; Mohamed Mahmoud Nasef; Efrem G Krivoborodov; Sohaira Ahmad; Alexey A Zanin; Yaroslav O Mezhuev; Amin Abbasi

doi:10.3390/polym13224040

A Degradable Inverse Vulcanized Copolymer as a Coating Material for Urea Produced under Optimized Conditions

Polymers (Basel). 2021 Nov 22;13(22):4040. doi: 10.3390/polym13224040.

Authors

Ali Shaan Manzoor Ghumman^{1

2}, Rashid Shamsuddin^{1

2}, Mohamed Mahmoud Nasef³, Efrem G Krivoborodov⁴, Sohaira Ahmad⁵, Alexey A Zanin⁴, Yaroslav O Mezhuev⁴, Amin Abbasi¹

Affiliations

¹ Chemical Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar 32610, Perak Darul Ridzuan, Malaysia.
² HICoE, Centre for Biofuel and Biochemical Research (CBBR), Institute of Sustainable Building, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Perak, Malaysia.
³ Department of Chemical and Environmental Engineering, Malaysia Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, Kuala Lumpur 54100, Malaysia.
⁴ Institute of Chemistry and Sustainable Development, Dmitry Mendeleev University of Chemical Technology of Russia, Miusskaya Sq. 9, 125047 Moscow, Russia.
⁵ Department of Electrical Engineering, Wah Engineering College, University of Wah, Wah Cantt 47040, Punjab, Pakistan.

Abstract

Global enhancement of crop yield is achieved using chemical fertilizers; however, agro-economy is affected due to poor nutrient uptake efficacy (NUE), which also causes environmental pollution. Encapsulating urea granules with hydrophobic material can be one solution. Additionally, the inverse vulcanized copolymer obtained from vegetable oils are a new class of green sulfur-enriched polymer with good biodegradation and better sulfur oxidation potential, but they possess unreacted sulfur, which leads to void generations. In this study, inverse vulcanization reaction conditions to minimize the amount of unreacted sulfur through response surface methodology (RSM) is optimized. The copolymer obtained was then characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). FTIR confirmed the formation of the copolymer, TGA demonstrated that copolymer is thermally stable up to 200 °C temperature, and DSC revealed the sulfur conversion of 82.2% (predicted conversion of 82.37%), which shows the goodness of the model developed to predict the sulfur conversion. To further maximize the sulfur conversion, 5 wt% diisopropenyl benzene (DIB) as a crosslinker is added during synthesis to produce terpolymer. The urea granule is then coated using terpolymer, and the nutrient release longevity of the coated urea is tested in distilled water, which revealed that only 65% of its total nutrient is released after 40 days of incubation. The soil burial of the terpolymer demonstrated its biodegradability, as 26% weight loss happens in 52 days of incubation. Thus, inverse vulcanized terpolymer as a coating material for urea demonstrated far better nutrient release longevity compared with other biopolymers with improved biodegradation; moreover, these copolymers also have potential to improve sulfur oxidation.

Keywords: central composite design; coated urea; dip-coating; inverse vulcanization; response surface methodology; slow-release fertilizers; sulfur polymers; urea.