Papers by Keyword: Radiation Grafting

Abstract: This paper studied the alternative method for determination of percentage of grafted content in the grafted low density polyethylene (LDPE) film with black seed oil (BSO). BSO was grafted onto LDPE by pre-irradiation grafting method and the grafted samples were evaluated using FTIR qualitative and quantitative analysis. The grafting yield was calculated quantitatively from absorbance peak of two difference peak (1464cm^-1 and 1746cm^-1). Control LDPE film shows no absorbance peak at wavenumber of 1746cm^-1 while, a peak appears for grafted film at the same wavenumber. Therefore, it is possible to consider the peak area in this wavenumber as the grafting extension of BSO in LDPE film. Meanwhile, concerning the infrared (IR) fingerprint of LDPE film, consistent peak characteristic bands of LDPE are also present for all grafted sample at 1464cm^-1. Thus, the grafting yield is computed by using these peaks. Then, further confirmation grafting of BSO onto LDPE film was supported by the XPS spectroscopy. The atomic composition of C decreased 13% after LDPE film was grafted with BSO. While, the O content increases from values of 6.9% to 19.2% after grafting reaction. The increment percentage of O1s after grafting reaction mainly caused by the incorporation of oxygen content of a new polar functional groups of BSO on the surface of LDPE films. These results are in good agreement with FTIR analysis.

Abstract: Glycidyl methacrylate (GMA) was grafted onto the surface of HDPE particles by radiation grafting and emulsion graft copolymerization. And subsequent ring-opening reaction of expoxy groups in poly-GMA graft chains with N-methylglucamine (NMG) was conducted to synthesis the boron adsorbent. The synthesis condition (radiation dose and NMG concentration) was optimized and characterized by IR and SEM. Adsorption behaviors of the boron adsorbent for boron removal presented that adsorption kinetics was well described by pseudo-second-order kinetic mode. The adsorption isothermal was well fitted with both Langmuir and Freundlich isotherm models. The adsorption capacity for boron reached 15.63 mg/g at optimal pH 8. Dynamic experiment revealed that boron could be efficiently adsorbed by the boron adsorbent and fully desorbed using 13 BV of 1 mol/L HCl.

Abstract: In this work we represent the results for the development of proton conductive membranes by radiochemical modification of thin PVDF films with their subsequent sulfonation. Radiation source were ⁴He ions with energy of 27 MeV produced by cyclotron R-7M the FTI TPU. The results of IR-spectroscopy, gravimetric analysis and microscopy are represented to evaluate changes in membranes properties. It was shown that the deepness of modificated gel can be controlled by radiation.

Abstract: The kinetic behavior of a new adsorbent prepared by radiation induced grafting of vinyl benzyl chloride (VBC) onto nylon-6 fibers followed by functionalization with N-methyl-D-glucamine was investigated using pseudo second-order kinetic model. The linear method and non-linear regression methods were compared to determine the best fitting for the kinetic model describing the adsorption of boron by the new adsorbent. Four pseudo second-order kinetic linear equations were presented. A type-1 pseudo second-order linear method was found to fit best the experimental data. Non-linear regression method was found to be more appropriate to describe the boron adsorption by the fibrous adsorbent which has also shown fast kinetics.

Abstract: As the demand for radiation grafted Proton Exchange Membranes (PEMs) is intensifying, interest in new materials for preparing PEM is rapidly increasing. This study aims to develop sustainable low-cost highly conductive PEM. In our work we have prepared linear low density polyethylene (LLDPE) based PEM and investigated the membrane characteristics. Simultaneous radiation grafting technique has been applied to introduce the styrene monomer onto the LLDPE films by UV radiation under atmospheric circumstances. It has been observed that grafting yield gradually changes depending on the irradiation time and monomer molar ratio. We have performed experiments to assess certain membrane properties, such as water uptake, ion exchange capacity with respect to their applicability in fuel cells. Our experimental results demonstrate the effectiveness of LLDPE based PEM as a cation exchange membrane.

Abstract: Poly(ethylenetarepthalate) (PET)-based polymer electrolyte membranes (PEMs) for fuel cells were successfully prepared by grafting of allyl methacrylate (AMA) and allyl acetate separately onto PET films under UV- radiation. A consequent selective sulfonation of the grafted films was performed by chlorosulfonic acid (ClSO¬3H) under milder condition. The sulfonation reaction proceeded at the grafted chains, as a result the grafted films successfully transformed to a PEM. It has been confirmed by titrimetric and gravimetric analyses as well as FTIR spectroscopy. The ion exchanges capacities (IECs) of the PEMs were studied by changing the degree of grafting and sulfonation. IECs of the PEMs prepared by grafting of allylmethacrylate (AMA) and allyl acetate onto PET were found in the ranges of 0.013-0.035 mmol/g and 0.03114-0.04125 mmol/g respectively. Water uptake, acid and hydrogen peroxide tolerance, tensile strength and proton transfer rate of the PEMs were studied. Electrical properties such as resistance, dielectric loss, and capacitance of the PEMs were also studied using impedance analyzer.

Abstract: Positron annihilation lifetime spectroscopy (PALS) measurements were performed on polymer electrolyte membranes (PEMs) synthesized by radiation-induced graft polymerization of styrene into crosslinked-polytetrafluoroethylene (cPTFE) films and subsequent sulfonation. The base cPTFE and polystyrene grafted films were also measured as references. The cPTFE based PEM was found to have free-volume holes with different radius of 0.28-0.30 nm and 0.44-0.45 nm. The larger holes may be located in PTFE amorphous regions, while the smaller ones are considered to exist in both PTFE crystallites and poly(styrene sulfonic acid) grafts containing no water.

Abstract: This paper focuses on an effective way to improve the thermostability of poly-β-hydroxybutyrate (PHB). Maleic anhydride (MA) is grafted onto PHB by 60Co γ of radiation. The spectra of both 1HNMR and 13CNMR were investigated following the radiation-induced polymerization. The results are consistent with successful grafting of the MA monomer onto the PHB, with a low graft degree. The graft degree and viscosity-average molecular weight Mηof the radiated samples were also investigated. The results observed through TGA demonstrate that thermostability has been measurably improved with the introduction of MA groups. These significant results suggest that wide commercial application of PHB may be possible.