Ruey Shan Chen

Highly porous regenerated cellulose hydrogel and aerogel prepared from hydrothermal synthesized cellulose carbamate

Here, a stable derivative of cellulose, called cellulose carbamate (CC), was produced from Kenaf (Hibiscus cannabinus) core pulp (KCP) and urea with the aid of a hydrothermal method. Further investigation was carried out for the amount of nitrogen yielded in CC as different urea concentrations were applied to react with cellulose. The effect of nitrogen concentration of CC on its solubility in a urea-alkaline system was also studied. Regenerated cellulose products (hydrogels and aerogels) were fabricated through the rapid dissolution of CC in a urea-alkaline system. The morphology of the regenerated cellulose products was viewed under Field emission scanning electron microscope (FESEM). The transformation of allomorphs in regenerated cellulose products was examined by X-ray diffraction (XRD). The transparency of regenerated cellulose products was determined by Ultraviolet–visible (UV–Vis) spectrophotometer. The degree of swelling (DS) of regenerated cellulose products was also evaluated. This investigation provides a simple and efficient procedure of CC determination which is useful in producing regenerated CC products.

Mechanical, thermal, and electrical properties of graphene oxide–multiwalled carbon nanotubes-filled thermoplastic elastomer nanocomposite

This article studies the enhancement in the properties of thermoplastic natural rubber (TPNR) reinforced by graphene oxide (GnO) and multiwalled carbon nanotubes (MWCNTs). TPNR is a blend of polypropylene and liquid natural rubber (NR), which is used as a compatibilizer and NR at a percentage of volume ratio 70:10:20, respectively. Using TPNR as the host matrix, a number of TPNR/carbon nanotubes (CNTs), TPNR/GnO, and hybrid TPNR/GnO/CNTs nanocomposites are processed and their mechanical, thermal, and electrical properties are characterized. The results extracted from tensile and impact test showed that tensile strength, Young’s modulus, and storage modulus of TPNR/GnO/MWCNTs hybrid nanocomposite increased as compared with TPNR composite and TPNR/GnO nanocomposite but lower than TPNR/MWCNTs nanocomposite. On the other hand, the elongation at break considerably decreased with increasing the content of both types of nanoparticles. Based on the experimental results, the thermal, electrical conductivity of a 0.5 wt% MWCNTs-reinforced sample increased as compared with a pure TPNR and other MWCNTs/GnO-reinforced composites. The improved dispersion properties of the nanocomposites can be due to altered interparticle interactions. MWCNTs, GnO, and MWCNTs–GnO networks are well combined to generate a synergistic effect that is shown by scanning electron microscopy micrographs. With the existence of this network, the mechanical, thermal, and electrical properties of the nanocomposite were improved significantly.

The Effects of Antioxidants Content on Mechanical Properties and Water Absorption Behaviour of Biocomposites Prepared by Single Screw Extrusion Process

The performance of hybrid fillers between rice husk and sawdust filled recycled high density polyethylene (rHDPE) with the presence of antioxidants (IRGANOX 1010 and IRGAFOS 169, with the ratio of 1 : 1) was investigated. The biocomposites with 30 wt% of matrix and around 70 wt% of hybrid fillers (rice husk and sawdust) and different antioxidants’ contents (0 to 0.7 wt%) were prepared with single screw extruder. Increasing the amount of antioxidants in biocomposites reduced the modulus of elasticity and modulus of rupture on flexural testing. The addition of antioxidants increased the tensile and impact strength of biocomposites. From the study, samples with 0.5 wt% of antioxidants produce the most reasonable strength and elasticity of biocomposites. Furthermore, the effect of antioxidants content on water uptake was minimal. This might be caused by the enhanced interfacial bonding between the polymer matrix and hybrid fillers, as shown from the morphology by using scanning electron microscopy (SEM).

Effect of compatibilizer on impact and morphological analysis of recycled HDPE/PET blends

Blends based on recycled high density polyethylene (rHDPE) and recycled polyethylene terephthalate (rPET) were prepared using a corotating twin screw extruder. PET and HDPE are incompatible polymers and their blends showed poor properties. Compatibilization is a step to obtain blends with good mechanical properties and in this work, ethylene glycidyl methacrylate copolymer (E-GMA) was used as a compatibilizing agent. The effect of blends based on rHDPE and rPET with and without a compatibilizer, E-GMA were examined. From the studies clearly showed that the addition of 5% E-GMA increased the impact strength. SEM analysis of rHDPE/rPET blends confirmed the morphological interaction and improved interfacial bonding between two phases.

Optimization of high filler loading on tensile properties of recycled HDPE/PET blends filled with rice husk

Biocomposites of recycled high density polyethylene / recycled polyethylene terephthalate (rHDPE/rPET) blend incorporated with rice husk flour (RHF) were prepared using a corotating twin screw extruder. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to improve the fibre-matrix interface adhesion. The effect of high filler loadings (50–90 wt%) on morphology and tensile properties of compatibilized rHDPE/rPET blend was investigated. The results of our study shown that composite with 70 wt% exhibited the highest tensile strength and Young’s modulus, which are 22 MPa and 1752 MPa, respectively. The elongation at break decreased with increasing percentage of RHF. SEM micrograph confirmed fillers dispersion, morphological interaction and enhanced interfacial bonding between recycled polymer blends and rice husk. It can be concluded that the optimum RHF content is 70 wt% with maximum tensile strength.

UV/O3 treatment as a surface modification of rice husk towards preparation of novel biocomposites

The use of rice husks (RH) to reinforce polymers in biocomposites are increasing tremendously. However, the incompatibility between the hydrophilic RH fibers and the hydrophobic thermoplastic matrices leads to unsatisfactory biocomposites. Surface modification of the fiber surface was carried out to improve the adhesion between fiber and matrix. In this study, the effect of surface modification of RH via alkali, acid and ultraviolet-ozonolysis (UV/O3) treatments on the properties of composites recycled high density polyethylene (rHDPE) composites was investigated. The untreated and treated RH were characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The composites containing 30 wt% of RH (treated and untreated) were then prepared via extrusion and followed by compression molding. As compared to untreated RH, all surface treated RH exhibited rougher surface and showed improved adhesion with rHDPE matrix. Tensile strength of UV/O3-treated RH composites showed an optimum result at 18.37 MPa which improved about 5% in comparison to the composites filled with untreated RH. UV/O3 treatment promotes shorter processing time and lesser raw material waste during treatment process where this is beneficial for commercialization in the future developments of wood plastic composites (WPCs). Therefore, UV/O3 treatment can be served as an alternative new method to modify RH surface in order to improve the adhesion between hydrophilic RH fibre and hydrophobic rHDPE polymer matrix.

Tensile and morphology properties of PLA/LNR blends modified with maleic anhydride grafted-polylactic acid and -natural rubber

This research was carried out to investigate the addition of grafted copolymers of maleic anhydride grafted-polylactic acid(PLA-g-MA) and maleic anhydride grafted-natural rubber (NR-g-MA) on the tensile and morphology properties of polylactic acid/ liquid natural rubber (PLA/LNR) blends. Prior to blend preparation, the PLA-g-MA and NR-g-MA was first self-synthesized using maleic anhydride (MA) and dicumyl peroxide (DCP) as initiator together with the PLA and NR respectively. The PLA/LNR, PLA/LNR/PLA-g-MA and PLA/LNR/NR-g-MA blends were prepared via melt-blending method. The loading of PLA-g-MA and NR-g-MA was varied by 5, 10 and 15 wt% respectively. The addition of PLA-g-MA led to increment in tensile strength with 5 and 10 wt% while NR-g-MA gives lower than controlled sample (PLA/LNR blend). Scanning electron microscope (SEM) showed the interaction of the components in the blends. The PLA/LNR compatibilized with PLA-g-MA and NR-g-MA shows greater dispersion and adhesion.

Effect of processing parameters on tensile properties of thermoplastic natural rubber (TPNR) blend with polyaniline

This study was aimed to determine the optimum processing parameter for the fabrication of thermoplastic natural rubber (TPNR), polyaniline (PANI) incorporated with liquid natural rubber (LNR) as a compatibilizer. The TPNR matrix, which comprised of linear low-density polyethylene (LLDPE), natural rubber (NR), and LNR in the ratio of 50:40:10, and TPNR/PANI (90 wt % /10 wt %) blend were prepared via melt blending method using Haake Rheomix internal mixer with various mixing parameter condition. The independent effects of mixing temperature (120 – 150°C), mixing speed of rotation (20-50 rpm) and time of mixing (13, 14, 15 minutes) on the tensile properties were investigated. Tensile results showed that the optimum processing parameter TPNR/PANI blend obtained at 130°C, 30 rpm, and 13 minutes. Compared to TPNR, the presence of PANI in TPNR improved the tensile strength and Young Modulus as compared to the neat TPNR acted as a control sample. The morphology characterization of TPNR and TPNR/PANI was examined ...

Optimization of processing parameter for fabrication of polylactic acid/liquid natural rubber/graphene nanoplatelet by tensile properties

A study on processing parameter of polylactic acid (PLA) and graphene nanoplatelet (GNP) prepared via melt blending method using Haake Rheomix internal mixer. In this study liquid natural rubber (LNR) was used as compatibilizer and at the same time introducing ductile property into the nanocomposite blending. In order to determine the optimal processing parameter, nanocomposites were fabricated from PLA: LNR with ratio of 90:10, and 0.2 wt. % of graphene nanoplatelet with different mixing parameter condition; mixing temperature, rotor speed and mixing time. The optimal processing parameter was determined from the results of tensile testing. An optimum processing parameter of polymer nanocomposite was obtained at 180 °C of mixing temperature, 100 rpm of mixing speed and 14 min of mixing time. The SEM micrographs confirmed the dispersion of GNP in the PLA matrix.

Characterization of Rice Husk Biofibre-Reinforced Recycled Thermoplastic Blend Biocomposite

In this century, the developing country has a high potential towards the growth of green composites, and therefore there is significant achievement in green technology especially in the field of building constructions and automotive because of the environment and sustainability issues. The market for development of advanced biocomposite materials produced from biomass and recyclable post-consumer plastics is increasing. Natural fibre-reinforced biocomposites based on rice husk biofibre (RHB), recycled high-density polyethylene (rHDPE) and recycled polyethylene terephthalate (rPET) were prepared through a two-step extrusion and hot pressing. The influence of thermoplastic blend (TPB) matrix types (uncompatibilized and compatibilized with 5 parts per hundred compound (phc) ethylene-glycidyl methacrylate (E-GMA) copolymer) and high fibre contents of 50, 60, 70 and 80 wt% RHB on the composite properties was studied. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to enhance the interfacial adhesion of the fibre-matrix phases. Results showed that water absorption, thickness swelling (TS) and tensile and flexural properties enhanced tremendously with the increase of rice husk filler loadings. Biocomposites based on compatibilized blend matrix exhibited higher mechanical properties and dimensional stability than those based on uncompatibilized ones. Thermal analysis results from thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated the notable improvement in thermal stability as the added rice husk (RH) fibre content increased. From these results, we can conclude that RHF can work well with rHDPE/rPET thermoplastic blend for manufacturing high loading biocomposite products.