Zeta Potential and Environmental Scanning Electron Microscopy Analysis in Deproteinisation of Natural Rubber Latex

Abstract

This paper describes the effect of protein denaturants namely, urea and sodium dodecyl sulphate (SDS) in the deproteinisation of high ammonia natural rubber latex (HA-NRL). It had been shown that latex proteins were reduced more in the presence of urea alone (48%) than in the presence of SDS (18%). The synergistic effect when both urea and SDS were used in the latex deproteinisation attributed to the higher protein removal efficacy (55%). Higher zeta potential value was observed when only SDS was used, suggesting higher colloidal stability. Environmental Scanning Electron Microscopy (ESEM) revealed that without SDS, the use of urea single-handedly in the deproteinisation process promoted aggregation of latex particles, possibly due to the dismissal of latex proteins which helped to stabilise latex colloidal. Thus, it is most likely that urea serves as a protein unfolding agent during latex deproteinisation process, while SDS functions as a latex stabiliser with no significant effects on latex proteins discharge.Keywords: urea, sodium dodecyl sulphate, deproteinisation, zeta potential, environmental scanning electron microscopy Abstrak Kertas kerja ini menghuraikan kesan bahan-bahan pengubah sifat protein iaitu urea dan natrium dodekil sulfat (NDS) dalam penyahprotein lateks getah asli tinggi ammonia (HA-NRL). Ia telah menunjukkan bahawa protein lateks lebih banyak dikurangkan dengan kehadiran urea sahaja (48%) berbanding dengan kehadiran NDS sahaja (18%). Keberkesanan penyingkiran protein yang lebih tinggi (55%) mungkin telah disebabkan oleh kesan sinergi apabila kedua-dua urea dan NDS digunakan di dalam penyahprotein lateks. Nilai keupayaan zeta yang tinggi diperhatikan apabila hanya NDS digunakan, menunjukkan kestabilan koloid yang lebih tinggi. Pengimbas Persekitaran Mikroskopi Elektron (ESEM) menunjukkan bahawa tanpa NDS, penggunaan hanya urea dalam proses penyahprotein menyumbang kepada kesan pengagregatan zarah lateks, kemungkinan disebabkan oleh penyingkiran protein lateks yang membantu dalam kestabilan koloid lateks. Oleh yang demikian, besar kemungkinan fungsi utama urea semasa proses penyahprotein lateks adalah sebagai ejen pembuka protein manakala NDS berfungsi sebagai penstabil lateks tanpa kesan ketara pada penyingkiran protein lateks.

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“…On the other hand, Ariyawiriyanan [ 56 ] suggests that the zeta potential has an incidence on the particle sizes of the DPNR, finding that at lower zeta potentials the particle size decreases. Therefore, it is inferred that possibly the smallest particle sizes were obtained from the system PEG6000 L. The zeta potential of Colombian NRFL shows similar values as reports of other countries [ 44 , 59 , 60 ].…”

A facile approach to fabricate room temperature intrinsic self-healing fabrics

“…This could be explained by the phospholipids, carbohydrates, proteins and other non-rubber ingredients contributing charge species to HANRL, resulting in significant negative zeta potential values. 36 The highest negative zeta potential for the HANRL with 30 phr zinc thiolate showed that the colloidal particles were stabilised, which thus inhibited particle aggregation, unlike with lower zeta potential values. Moreover, the presence of potassium oleate acted as a colloid stabiliser, preventing rubber particle coalescence in the controlled sample.…”