Browsing by Author "Ng, Zhi Chien"

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Citation - WoS: 8
Citation - Scopus: 10
Development of Surface Modified Pu Foam With Improved Oil Absorption and Reusability Via an Environmentally Friendly and Rapid Pathway
(Elsevier Sci Ltd, 2022) Seah, Mei Qun; Ng, Zhi Chien; Lau, Woei Jye; Gürsoy, Mehmet; Karaman, Mustafa; Wong, Tuck-Whye; Ismail, Ahmad Fauzi
Although the commercial polyurethane (PU) foams are hydrophobic in nature, they generally show low degree of reusability for oil and organic solvent absorption. In this work, we proposed a solvent-free and rapid surface functionalization approach based on chemical vapor deposition (CVD) process to improve the surface characteristics of PU foam, increasing not only its reusability but also its absorption capacity. Among the monomers used to functionalize the surface of foam, our results showed that only hexamethyldisiloxane (HMDSO) and 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) were promising to increase the absorption performance of the control PU foam, owing to the enhanced foam's surface hydrophobicity (with contact angle increased from similar to 106 degrees to 120-135 degrees) without altering the foam's porosity. These promising features are attributed to the formation of ultrathin highly hydrophobic yet uniform layer on the foam surface. Further investigation indicated that the modified foams outperformed the control foam for the multicycle cyclohexane and crude oil absorption (up to 10 cycles) by showing significantly higher absorption capacity. The reusability of the modified foams could be further improved when ethanol was employed to rinse the saturated foam after each absorption cycle. Such solvent rinsing help in maintaining the foam absorption capacity. In conclusion, the proposed greener surface modification method clearly demonstrated its effectiveness in functionalizing the PU foam, leading to higher absorption capacity against cyclohexane and crude oil as well as higher degree of reusability.
Citation - WoS: 22
Citation - Scopus: 23
A Green Approach To Modify Surface Properties of Polyurethane Foam for Enhanced Oil Absorption
(MDPI, 2020) Ng, Zhi Chien; Roslan, Rosyiela Azwa; Lau, Woei Jye; Gürsoy, Mehmet; Karaman, Mustafa; Jullok, Nora; Ismail, Ahmad Fauzi
The non-selective property of conventional polyurethane (PU) foam tends to lower its oil absorption efficiency. To address this issue, we modified the surface properties of PU foam using a rapid solvent-free surface functionalization approach based on the chemical vapor deposition (CVD) method to establish an extremely thin yet uniform coating layer to improve foam performance. The PU foam was respectively functionalized using different monomers, i.e., perfluorodecyl acrylate (PFDA), 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA), and hexamethyldisiloxane (HMDSO), and the effect of deposition times (1, 5 and 10 min) on the properties of foam was investigated. The results showed that all the modified foams demonstrated a much higher water contact angle (i.e., greater hydrophobicity) and greater absorption capacities compared to the control PU foam. This is due to the presence of specific functional groups, e.g., fluorine (F) and silane (Si) in the modified PU foams. Of all, the PU/PHFBA(i)foam exhibited the highest absorption capacities, recording 66.68, 58.15, 53.70, and 58.38 g/g for chloroform, acetone, cyclohexane, and edible oil, respectively. These values were 39.19-119.31% higher than that of control foam. The promising performance of the PU/PHFBA(i)foam is due to the improved surface hydrophobicity attributed to the original perfluoroalkyl moieties of the HFBA monomer. The PU/PHFBA(i)foam also demonstrated a much more stable absorption performance compared to the control foam when both samples were reused for up to 10 cycles. This clearly indicates the positive impact of the proposed functionalization method in improving PU properties for oil absorption processes.