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In this research, eutectic-based ionic liquid specifically choline chloride/glycerol was prepared at a 1:2 mole ratio. The choline chloride/glycerol was added with the different content of surfactant (hexadecyltrimethylammonium bromide). The choline chloride/glycerol-hexadecyltrimethylammonium bromide was introduced into high-density polyethylene/agar biocomposites through melt mixing. The mechanical testing results indicated that the impact strength and tensile extension of the biocomposites increased with the introduction of the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The scanning electron microscope, differential scanning calorimetry and thermal gravimetric analysis results exhibited that significant decrease in the number of agar fillers pull-out, melting point and thermal decomposition temperatures of the biocomposites are also due to the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The Fourier transform infrared spectra and X-ray diffractometer patterns of the biocomposites introduced with the choline chloride/glycerol-hexadecyltrimethylammonium bromide demonstrate the presence of physical interactions, which contributes to the increase of compatibility between both high-density polyethylene and agar. In conclusion, high-density polyethylene/agar biocomposites could be compatibilized with eutectic-based ionic liquid containing surfactant, choline chloride/glycerol-hexadecyltrimethylammonium bromide.

Agarose films were formed with the addition of 30 to 70 wt% choline chloride/urea eutectic-based ionic liquid (ChCl/Urea). The ChCl/Urea was prepared through complexation at a 1:2 mole ratio. The films were prepared by dissolving ChCl/Urea in distilled water followed by dispersion of the agarose at 95 °C. The solution was gelled at room temperature, and the formed gel was dried in an oven overnight at 70 °C. Mechanical testing indicated that the agarose film containing 60 wt% ChCl/Urea had higher tensile extension and tensile strain at break compared to the pristine agarose film. The addition of ChCl/Urea also reduced the glass transition temperature (T g ) of agarose films. Crosssection SEM images of the agarose films showed that surface roughness disappeared with the incorporation of ChCl/Urea. FTIR spectra confirmed the presence of intermolecular hydrogen bonding between agarose and ChCl/Urea. XRD patterns demonstrated that an amorphous phase was obtained when ChCl/Urea was added. Agarose films containing more ChCl/Urea exhibited higher transparency, as measured by a UV-Vis spectrometer. In summary, the physicochemical properties of agarose films were evidently affected by the incorporation of the ChCl/Urea as a plasticizing agent.

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An ionic liquid, 1-n-butyl-3-methylimidazolium chloride (BmimCl) was blended with urea at 1:1 mole ratio to create a BmimCl/Urea mixture. The agarose/talc composite films containing the BmimCl/Urea mixture were then acquired through a gelation method. The weight ratio of agarose and talc was fixed at 4:1, while the content of BmimCl/Urea was varied from 0 to 10 wt % relative to the overall weight of the composite films. The tensile stress and modulus results showed the optimum BmimCl/Urea content in the composite film lies at 8 wt %. The talc particles are embedded in the agarose matrix and there are no pullouts for the composite films containing BmimCl/Urea as demonstrated by SEM micrographs. The addition of BmimCl/Urea increased the glass transition temperature of the composite films, however, the thermal decomposition temperature decreased drastically. FTIR and FT-Raman spectra indicated the existence of interaction between agarose and talc, which improves their interfacial adhesion. As a conclusion, a BmimCl/Urea mixture can be utilized as a coupling agent for agarose/talc composite films.

In this study, lignin was isolated from rubber wood by means of ionic liquid (1,3-dimethylimidazolium methylsulfate). The optimum parameters to isolate lignin were investigated which include the concentrations of ionic liquid (0.1, 0.2, 0.3, 0.4, 0.5 moles), isolation durations (30, 60, 90, 120, 150 minutes), and isolation temperatures (25, 40, 60, 80, 100°C). The optimum parameters for lignin isolation are 0.5 moles concentration, 120 minutes and 100ºC. Lignin could be isolated from rubber wood up to 13.03wt.% by ionic liquid however, in comparison with acid and alkaline isolation, they give better yields than ionic liquid which 22.15wt.% and 18.56wt.% of lignin, respectively. Lignin preliminary structures isolated by ionic liquid have been confirmed based on Fourier transform infrared (FTIR) results. From these results, isolated lignin by ionic liquid provides lignin without other related isolative. Apart from that, ionic liquid also could be recycled up to three times compared to acid and alkaline isolation methods.

The recent growth of nanotechnology consciousness has enhanced the attention of researchers on the utilization of polymer nanocomposites. Nanocomposite have widely been made by using synthetic, natural, biosynthetic, and synthetic biodegradable polymers with nanofillers. Nanofillers are normally modified with surfactants for increasing the mechanico-thermal properties of the nanocomposites. In this short review, two types of polymer nanocomposites modified by surfactants are classified, specifically surfactant-modified inorganic nanofiller/polymer nanocomposites and surfactant-modified organic nanofiller/polymer nanocomposites. Moreover, three types of surfactants, specifically non-ionic, anionic, and cationic surfactants that are frequently used to modify the nanofillers of polymer nanocomposites are also described. The effect of surfactants on mechanico-thermal properties of the nanocomposites is shortly reviewed. This review will capture the interest of polymer composite researchers and encourage the further enhancement of new theories in this research field.

Three types of surfactants, specifically cationic, anionic, and nonionic, at different weight percentages were added into high-density polyethylene/low-density polyethylene/cellulose (HDPE/LDPE/cellulose) biocomposites via melt mixing. The cationic and anionic surfactants which are hexadecyltrimethylammonium bromide (HTAB) and sodium stearate (SS), respectively, were added from 4 to 20 wt%, whereas the nonionic surfactant which is sorbitan monostearate (SM) was added from 1 to 5 wt%. The mechanical testing results exhibited that the addition of HTAB increased tensile strength and tensile modulus, while SS deteriorated mechanical properties, while SM increased impact strength and tensile extension of the biocomposites. Based on the mechanical properties results, optimum weight percentages of HTAB and SM were 12 wt% and 4 wt%, respectively. The scanning electron microscopic micrographs displayed that the amount of cellulose fillers pullout decreased with the addition of HTAB, followed by SM, but it increased with SS. Fourier transform infrared spectra, X-ray diffractometer patterns, thermogravimetric analysis results, and differential scanning calorimetry thermograms have confirmed the presence of physical interactions only with the addition of HTAB and SM. Based on the results, compatibilizing effect was found in HTAB, whereas SM has not showed compatibilizing effect but instead plasticizing effect. However, neither compatibilizing nor plasticizing effect was exhibited by SS.