Papers by Keyword: Grafting

Abstract: Grafting TiO₂ on PMMA was studied by atom-transfer radical-polymerization (ATRP). Each step in grafting process was monitored by fourier transform infrared spectroscopy (FT-IR), ¹H NMR and ¹³C NMR spectra. The glass temperature of grafted-PMMA film was determined by using differential scanning calorimetry (DSC). The morphology and bulk composition were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The surface composition was characterized by X-ray photoelectron spectroscopy (XPS). As results, a novel method of grafting TiO₂ on PMMA was successfully grafted and confirmed in various techniques. The photocatlytic activity was evaluated under UV and visible light irradiation. The reusability of TiO₂-g-PMMA films was studied in details.

Abstract: A novel hybrid flocculant of acrylamide and cellulose was synthesized by using microwave irradiation method. Cellulose was extracted from kenaf by using TAPPI method. 57.4% of percentage grafting and efficiency has been obtained from the grafting process. There are additional peaks that appeared in FTIR spectroscopy analysis that show PAM was grafted into cellulose backbone. The flocculation behavior was studied by using ethyl orange wastewater. The result shows that hybrid flocculant (cellulose-g-PAM) has potential to be used as flocculant in treating dyes waste water.

Abstract: The interaction of electron-beam with organic materials (e.g. Polymers, organic solvents, organic acids etc.) is known to modify their physico-chemical properties and, in many cases, these electron-beam modified materials are used for variety of societal applications. In this review article, we first describe the various types of accelerators to generate electron-beams of different energies, i.e. low (0.3 – 0.75 MeV), medium (0.75– 5 MeV) and high (5 – 10 MeV) energies, and emphasis is laid on various accelerators developed by Bhabha Atomic Research Center (BARC), Trombay, India. The energetic electrons on interaction with organic materials create free radicals that lead to modifications in material through various mechanisms such as, cross-linking, scissioning, curing and grafting. An overview of these mechanisms is presented by citing appropriate examples. Applications of electron beam-modified organic materials in different areas including bio-medical, textile, environment protection, electrical, radiation dosimetry, etc. are reviewed. The prospects and challenges involved in the electron-beam processing of organic materials are presented.

Abstract: Grafting polymerization by reactive small molecules involves the formation of graft copolymers from a reaction between polymers and monomers. Monomer units can be propagated onto the polymer backbone to form a graft structure. In the polymer processing industry, the internal mixer is the most important piece of machinery. The study used the internal mixer as a reactor to make a reactive process with the interest in residence time,as the residence time is importance in the chemical reaction. By increase the residence time, the optimum degree of grafting may be occurred. The objectives of this study are to increase the knowledge and understanding of the internal mixer process, determine optimum residence time process variables for grafting LLDPE and study the effect of the residence time toward the LLDPE grafting process. Several residence times was choosing for the specified sample, to study the effect of the residence time which were 60 s, 120 s, 180 s, 240 s, 300 s and 600 s. Degree of grafting (DOG) was calculated to determine the grafting of LLDPE grafted copolymers and a series of samples in which degrees of grafting had been determined by chemical titration. Residence time at 300 s produces the optimum DOG of monomer onto polymer. Longer residence time will produce high degree of grafting but will cause other issues such as increasing in gel content and lower the mechanical properties of the grafted polymer.

Abstract: The graft copolymerization was carried out under nitrogen atmosphere using the free radical initiation technique. The blend formulations were first dry blended using a mixer before being milled into sheets on a two-roll mill at 170°C, and then hot pressed into composites specimens at 175°C for 10 min. The objective of this study to investigate the mechanical and thermal properties of PVC blends. The flexural strength and modulus of ungrafted composites increased with increasing filler content from 2 to 10 part per hundred resin (phr) while the grafted composites also increased only from 2 to 6 phr filler content. The flexural modulus of ungrafted was higher compared to the grafted composites whereas the grafted showed good flexural strength than ungrafted composites. The impact strength of both composites decreased with increasing filler content but the ungrafted composites showed good toughness than grafted composites. The thermal stability of both composites increased compared to unfilled PVC.

Abstract: The experimental study of the kinetics of styrene monomer accumulation in polyvinylidene fluoride films with radiation-chemical grafting of styrene monomer is presented. It is proved that the degree of grafting depends on the absorbed dose of helium ions, temperature and composition of the grafting solution.

Abstract: PET material has excellent performance and its modification of biocompatibility had been concerned for researchers. In this paper, graft polymerization of acrylamide on PET fiber by co-irradiation was investigated, and then treated in 5% available chlorine content of NaClO solution, which make the amide groups on the PET fiber surface into amine groups, and provide the reactive groups for further functional modification. The results showed that the moisture absorption of PET fiber increases after the grafting of acrylamide, and its hygroscopicity increases with the increase of grafting yields; after the amide groups converted into the amine groups, the hygroscopicity of PET fibers decreases. The chemical structure and surface morphology of PET fiber and modified products were characterized by ATR-FTIR and SEM, which certified that acrylamide had been successfully grafted on PET fibers and the amide groups on its surface had been converted into the amine groups.

Abstract: In this study, performance of polyacrylamide grafted cellulose flocculant derived from Pandan leaves to treat reactive black 5 (RB5) dye from aqueous solution were investigated. Response surface methodology (RSM) and Box-Behnken design (BBD) of experiment were employed to identify the optimum condition for chemical oxygen demand (COD) reduction in RB5 dye. The optimization was based on three operating variables; initial dye concentration, flocculant dosage and pH. The optimum condition for COD reduction was achieved at initial dye concentration of 0.03 g/l with flocculant dosage of 0.06 g, at pH 11.72. Under this condition, the reduction of COD was achieved up to 54.24%. Linear and quadratic effects of flocculant dosage and pH are the most significant in affecting the degree of flocculation efficiency. The coefficient of determination (R²) of 81.77% for percentage reduction of COD level confirms that the models used in predicting the degree of flocculation efficiency has a very good agreement with the experimental results.

Abstract: The present study utilized the capability of ambient-temperature plasma in modifying the surface properties of materials to activate the polyethylene terephthalate (PET) fiber surfaces. The effects of different plasma treatment parameters (such as plasma power, treatment time) and grafting parameters (such as grafting temperature, acrylic acid monomer concentration, grafting time) on the activation and grafting of the PET fibers were studied. The feasibility of applying ambient-temperature plasma combined with grafting technology for the preparation of ion exchangers in the heavy metal containing wastewater treatment was evaluated.

Abstract: The aim of this research was to modify Poly (lactic acid) (PLA) and Natural Rubber (NR) using maleic anhydride (MA). The preparation was carried out using internal mixer by free radical melt grafting reaction to produce PLA-g-MA and NR-g-MA as a compatibilizer. The effects of concentrations of MA (3-12 phr) were studied in details. The samples structure of copolymers were then characterized using ¹H nuclear magnetic resonance (¹H-NMR) and Fourier transforms infrared spectrometer (FTIR). Quantities of grafted MA (% grafting) were characterized by titration analysis and when increasing the monomer used, the quantities of the grafted MA on PLA and NR molecules also increased. The optimum grafting degree for PLA-g-MA and NR-g-MA was at 9 phr of MA with value of 1.63% and 5.02%, respectively.