Zunaida Zakaria
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Preferred name
Zunaida Zakaria
Official Name
Zunaida, Zakaria
Alternative Name
Zakaria, Zunaida
Zunaida, Z.
Zakaria, Z.
Main Affiliation
Scopus Author ID
57217205824
Researcher ID
M-6958-2019

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Development of porous epoxy micro-beads using ammonium bicarbonate through a single epoxy droplet in corn oil

2021-01-01 , Leemsuthep A. , Zunaida Zakaria , Tanrattanakul V. , Ramarad S. , Muniyadi M. , Jaruga T. , Munusamy Y. , Wnuk I. , Pietrusiewicz P.

This paper explored the effects of ammonium bicarbonate and different ratios of epoxy to polyamide on the formation of porous epoxy micro-beads through a single epoxy droplet. A single drop of a mixture, consisting of epoxy, polyamide, and ammonium bicarbonate, was dropped into heated corn oil at a temperature of 100 °C. An epoxy droplet was formed due to the immiscibility of the epoxy mixture and corn oil. The ammonium bicarbonate within this droplet underwent a decomposition reaction, while the epoxy and polyamide underwent a curing reaction, to form porous epoxy micro-beads. The result showed that the higher ammonium bicarbonate content in the porous, epoxy micro-beads increased the decomposition rate up to 11.52 × 10−3 cm3/s. In addition, a higher total volume of gas was generated when a higher ammonium bicarbonate content was de-composed. This led to the formation of porous epoxy micro-beads with a smaller particle size, lower specific gravity, and better thermal stability. At an epoxy to polyamide ratio of 10:6, many smaller micro-beads, with particle sizes ranging from 201 to 400 μm, were obtained at an ammonium bicar-bonate content of 10 phr. Moreover, the porous epoxy micro-beads with open pores were shown to have a low specific gravity of about 0.93 and high thermal stability at a high ammonium bicarbonate content. Based on the findings, it was concluded that porous epoxy micro-beads were successfully produced using a single epoxy droplet in heated corn oil, where their shape and particle size de-pended on the content of ammonium bicarbonate and the ratio of epoxy to polyamide used.

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Effect of sulphur vulcanization system on physical, morphological and thermal properties of natural rubber latex foam

2022-05-18 , Mohammad Syahrin Smail , Zunaida Zakaria , Hakimah Osman , Syarifah Nuraqmar Syed Mahamud , Munusamy Y.

Recently, several research studies have been implemented using sodium bicarbonate (NaHCO3) as a blowing agent on rubber foams, yet none has been found in natural rubber latex foam (NRLF). The use of NaHCO3 as a blowing agent in NRLF prepared by the Dunlop process can potentially develop greener foaming processes and more environmentally friendly foam in the industry of latex foam. This novel method is designed to manage the reduction of harmful waste disposal associated typically in producing the NRLF product which is useful for industry purposes. Hence, this research is presented to investigate the physical properties of NRLF such as relative foam density, crosslink density, average cell diameter, and thermogravimetric analysis (TGA) based on the influences of different sulphur vulcanization systems via conventional vulcanization (CV) system and efficient vulcanization (EV) system. The relative density and crosslink density were increased with an increase in NaHCO3 concentration with the CV system exhibiting higher value than the EV system. For average cell diameter, the results showed a decrease in both systems with the EV system having higher value than the CV system. Thermal stability from the TGA results was also improved at higher NaHCO3 concentration and for the use of the CV system as a foaming approach, the CV system has higher thermal stability than the EV system.

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Recycled polyethylene blends and composites: Current trend, technology, and challenges

2023-09-23 , Munusamy Y. , Zunaida Zakaria , Ismail H. , Nor Azura Abdul Rahim

Thermoplastics being a modern material had provided significant contribution to human civilization. Polyethylene (PE) being the highest consumed thermoplastic is gaining more momentum in production for application in the field of automotive, electrical, and food packaging. Environmental issues with single-usage trend of PE products had catalyzed various initiative to recycle PE specially to produce recycle PE blends and composites. Even though various laboratory-based development been successfully carried out to produce recycled PE blends and composites but its commercialization is still at infancy. Thus, in this chapter the current PE recycling methods, products, and its applications are being discussed and the challenges faced by industry for full-scale adaption of findings in laboratories are highlighted. Critical analysis on the production and products of recycled PE blends and composites are reported to provide the reader with future trends for practical approach in PE recycling at industrial scale. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.

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Melt behavior of polypropylene-co-ethylene composites filled with dual component of sago and kenaf natural filler

2022-02-10 , Nor Azura Abdul Rahim , Xian Loo Yu , Munusamy Y. , Zunaida Zakaria , Ramarad S.

A dual component natural filler system featuring discrete function appears to be suitable for modulating smooth flow of pseudo-plastic into formulated biodegradable polymer composite. Polypropylene-co-ethylene (PPcoE) filled with sago starch and different kenaf powder loadings were compounded using co-rotating twin-screw extruder to produce dual component polymer composite. The flow characteristics of the composites were measured using capillary rheometer and Bagley corrections were performed to achieve the true rheological data. In addition, data collected from the twin-screw extruder were used to calculate the composite apparent rheological value. The flow properties of PPcoE filled with sago starch (PPcoE/sago) exhibited deviation from the common non-Newtonian thermoplastic flow paths at high shear rates. Interestingly, the addition of kenaf powder into the PPcoE/sago starch blend stabilized the melted composite flow stream. The calculation of interfacial tension revealed that the flow corrections were related to the phase selective localization of kenaf particle, which preferably embedded between the sago particles rather than in the surrounding PPcoE phase thus reducing the effect of sago clustering. At higher extrusion temperature, the extruded composite indicated sign of flow instability due to factors of high amount of kenaf powder loading and the degradation of sago starch and PPcoE chains.

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Recycled polyethylene terephthalate blends and composites: Impact of pet waste, engineering design, and their applications

2023-09-23 , Zunaida Zakaria , Hakimah Osman , Nor Azura Abdul Rahim , Munusamy Y. , Ismail H.

Polyethylene terephthalate (PET) is one of the major polymers produced and has been widely used in downstream industries, such as the production of textile fibers, packaging bottles, and films. The increased use of PET is associated with its excellent properties, which include thermal resistance, lightweight, high transparency, good impact, and relatively low cost. This indirectly contributes to a large amount of PET solid waste, which is detrimental to human life and exacerbates environmental issues. As a result, conversion to new PET blends and composites is an efficient method to recycle PET and reduce waste. While research in this area is ongoing and improving with the development of new materials for various applications, its commercialization has yet to begin. This chapter focuses on the designation of recycled PET and its performance as new blends and composites. Among the other topics discussed are PET waste sources, recycling methods, and applications, as well as the challenges of recycling PET and converting this solid waste into value-added products. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.

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