Papers by Keyword: Grafting

Abstract: This research explored the synthesis of hydrogels from acrylamide-grafted durian rind cellulose using a microwave-assisted method. The objective of this research was to investigate the effect of cellulose preparation and duration of microwave irradiation on the swelling properties of the obtained bead hydrogel. The mixture of cellulose, acrylamide solution, and potassium peroxydisulfate as the initiator agent was irradiated by microwave at 640 W. FTIR analysis showed that acrylamide was grafted into durian rind cellulose successfully. This study found that bead gels from durian rind cellulose, which underwent delignification and bleaching methods, exhibited a greater swelling capacity (855%) after 180 minutes than bead gels from durian rind cellulose without these methods (807%). The optimum microwave irradiation time was found to be 540 s, resulting in a maximum swelling capacity of 676%.

Abstract: The main objective of this work was to produce grafted cellulose from coconut dregs. In this work, cellulose isolated from coconut dregs was grafted with various concentrations of glycidyl methacrylate (GMA). Cellulose-GMA prepared using 20% of ​​GMA produced the highest grafting percentage, where the grafting percentage reached 299.2%. The obtained grafted cellulose was characterized by FT-IR, XRD, and TGA. FT-IR spectra confirmed the formation of cellulose-GMA and XRD data showed a slight decrease in the crystallinity of cellulose after GMA addition from 6.98% to 6.02%, 5.57%, and 5.83% for cellulose-GMA prepared using 15%, 20%, and 25% of GMA, respectively. Cellulose-GMA showed higher thermal stability than cellulose, that potentially used in some applications at higher temperatures.

Abstract: Determination of the optimum composition of chitosan-grafted cellulose/TiO₂ film was performed using the Box-Behnken Design method from Response Surface Methodology (RSM). Apart from being able to determine the best composition for a composite, this method can also determine the influencing factors of the composition on the performance of the composite. This method was conducted by combining factorial group design. This design used three factors and three levels. Adsorption capacity data from the adsorption process and percent removal from the photocatalyst process were used as responses in determining the optimum composition of chitosan-grafted cellulose/TiO₂ films. Based on the results, the counterplot of grafted cellulose vs TiO₂ shows that both variables have the same influence, where the more grafted cellulose and TiO₂ added to the composite, the more adsorption capacity of the chitosan-grafted cellulose/TiO₂ film. The results from determining the composition, obtained the best composition, namely chitosan; grafted cellulose; TiO₂ each of 0.85; 0.2; 0.2 g.

Abstract: Herein, we have synthesized polypyrrole grafted graphene oxide (GO-g-PPy) nanohybrids by a free radical emulsion graft polymerization method. GO was used as the substrate for pyrrole grafting. The parameters of the graft polymerization reaction were optimized. The optimum concentrations of surfactant, monomer and initiator were 0.25 wt. %, 3 vol.%, and 7 wt.%, respectively. The maximum grafting percentage was 989.6% at these optimal reaction parameters. The formation of the grafted nanohybrids was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermal stability studies were carried out by thermogravimetric analysis (TGA). GO-g-PPy naohybrids can be used as functional additives or conductive materials for EMI shielding applications.

Abstract: Hybrids of graphene oxide (GO) are emerged as multifunctional nanomaterials since the realization of their technological potential in EMI shielding, water treatment, sensors, catalysis, and more. They can be formed by combining organic species onto a GO substrate. Recently, the graft polymerization method has been used to develop nanohybrids of GO with varieties of monomers such as aniline, acrylonitrile, glycidyl methacrylate, and 4-vinyl pyridine at PIEAS. Graft polymerization can be done by chemical or radiation methods. This process offers quite a good control to tailor the properties of desired product by optimizing the reaction parameters. If possible chemical modifications of nanohybrids will also open new applications in different research areas. An overview of research recent work carried out at PIEAS on the graft polymerization of monomers on a GO substrate is presented. This work describes the published work on the successful synthesis of the grafted nanohybrids and the importance of optimizing the reaction conditions to obtain good yield of desired product. The practical prospects of the grafted GO nanohybrids in selected applications has also been presented. These polymer grafted GO nanohybrids can be seen as a green materials in many potential applications.

Abstract: Silica nanocapsules (SiNC) utilization as adsorbent in pollution control have gained much attraction as SiNC are highly porous, have high surface area, excellent thermal and mechanical stability and a tuneable physicochemical property. In this study, microemulsion technique was used to synthesized SiNC. Effect of stirring rate as well as the effect of different method of amine functionalization i.e. grafting, wet impregnation, co-condensation, on the physicochemical properties of SiNC were studied. The stirring rate have significant effect on the physical properties of the SiNC. As the stirring speed increased from 200 rpm to 600 rpm, the particle diameter and the surface area decreases, 695 to 600 nm and 773 to 654 m²/g, respectively. The SEM and TEM analysis shows higher stirring rate produced surface with extensive damage while lower stirring rate produced a smoother surface. Different functionalization method affected the amount of amine groups incorporated into the SiNC. The FTIR spectra shows that the impregnation method incorporates higher amount of amine as indicated by the higher peak transmissions in the region 3450 – 3250 cm^-1. However, amine functionalization of SiNC resulted in decrease of surface area as surface pore of the SiNC were occupied by the amine moieties’ molecules. The optimum condition for synthesizing amine functionalized SiNC were determined to be at stirring rate of 450 rpm through wet impregnation method as the SiNC produced were of spherical shape with smooth surface, and a relatively high surface area of 695 m2/g and pore diameter of 601 nm. These physicochemical characteristics shows the synthesized amine functionalized SiNC have promising qualities for application as adsorbents.

Abstract: Unreported peroxymonosulfate/mandelic acid as a redox pair initiation system has been used to graft copolymerizes acrylonitrile onto our previously prepared starch nanoparticle (SNPs) in aqueous medium under nitrogen atmosphere. Optimization of the grafting conditions was studied and the grafting parameters were expressed in terms of graft yield %, graft reaction efficiency % and homopolymer %. Fourier transformer infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and thermal gravimetric analysis (TGA) techniques confirmed the synthesis of the precursor’s materials and the success of the grafting onto starch nanoparticle. The resultant copolymer was found to be more thermally stable and more resistance to biodegradability than the starch nanoparticle counterparts. Besides, the optimum conditions were obtained when using 1 g starch nanoparticle, 2 ml of AN (based on weight of substrate), 30 m mol/l potassium peroxymonosulphate, 8 m mol/l mandelic acid, 2 hours reaction time and 45°C of temperature.

Abstract: This study aims to explore modification of polyaniline nanofiber through grafting polymerization to increase its solubility and processability for application in aqueous environment. Grafting via electron beam radiation procedure is extremely productive in terms of time consumption and environmental friendliness. In this work, acrylic acid was grafted on to polyaniline nanofiber using electron beam irradiation. The influence of altering the electron beam power from 2-3 MeV, radiation dosage from 5-25 kGy, acrylic acid concentration from 10-100% and soaking time from 2-24 hours during graft polymerization were studied over the grafting percentage (%G). Grafting parameter was determined by weight changes before and after grafting procedure. Grafted polyaniline is characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA). Formation of new peak at 1700 cm-1 for FTIR spectroscopy analysis of grafted polyaniline confirmed grafting has taken place during irradiation.

Abstract: In this study, the certain chloromethylated polysulfone ultrafiltration membrane (CMPSF) was prepared via nonsolvent-induced phase separation (NIPS) method. Then the hydrophilic monomer was grafted on the CMPSF membrane through quaternary amination reaction. The structure of membrane was characterized by Fourier transform infrared and the properties were measured by pore size, contact angle and membrane water flux. The contact angle test results show that the hydrophilic performance of the membrane is improved due to the grafting modification. Meanwhile, water flux has a tendency to decrease with the increase of the reaction time due to the decrease in pore size. This indicates the rejection of membrane will be improved.

Abstract: The grafted materials of silaned-graphene oxide-mordenite (s-GO-MOR) were synthesized by grafting graphene oxide (GO) sheets to acid-treated mordenite and followed by functionalization with silane. GO sheets were prepared according to the modified Hummers method. 3-mercaptopropyltriethoxysilane (MPTES) was used as a silane coupling agent. The products were characterized by a Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy and thermogravimetric analysis. The results confirmed the success of s-GO-MOR and showed excellent thermal stability.