Electron Beam Irradiated Poly Research Articles

Properties of Slow Release Fertilizer Composites Made from Electron Beam-irradiated Poly(Butylene Succinate) Compounded with Oil Palm Biomass and Fertilizer

Electron beam irradiation at certain absorption doses can affect the chain scission and crosslinking of poly(butylene succinate) (PBS) molecules, as well as their thermal properties. In this study, slow release fertilizer composites were produced by compounding neat PBS with NPK fertilizer and oil palm empty fruit bunch using a twin-screw extrusion method. It was found that granular PBS irradiated with up to 50 kGy remarkably improved the bonding and dispersion of the PBS matrix. The subsequent experiment also showed that the biodegradation of slow release fertilizer composites in soil could be improved via electron beam irradiation.

Optical properties and ionic conductivity studies of an 8 MeV electron beam irradiated poly(vinylidene fluoride-co-hexafluoropropylene)/LiClO4electrolyte film for opto-electronic applications

The influence of 8 MeV energy electron beam (EB) irradiation on optical properties and ionic conductivity of PVDF–HFP/LiClO4 (90 : 10 PHL10) electrolyte film with 40, 80 and 120 kGy doses. The FT-IR results show that C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> O bond stretching at 1654 cm−1 is due to the degradation of polymer chains and the CH2 bond wagging intensity at 1405 cm−1 corresponds to C–H bond scissioning in the 120 kGy dose irradiated film. 1H and 13C NMR spectroscopy was performed and the 13C NMR spectra confirm the effect of EB irradiation of the PHL10 polymer electrolyte by sharpening and splitting the spectral lines with increasing EB dose and revealing a new spectral line at 162.80 ppm with a 120 kGy EB dose. The size and shape of the porous morphology was drastically changed, becoming deeply porous with a visible inner hollow shaped structure, suggesting increased amorphous character upon irradiation. The absorption band of the unirradiated film observed at 202 nm in the ultraviolet region is shifted to 274 nm after irradiation due to inter band transition of electrons from the valence band to the conduction band and the optical band gap decreasing from 3.49 eV in the unirradiated film to 2.64 eV with a 120 kGy EB dose. Segmental motion in the polymer matrix leads to a decrease in the local viscosity by increasing the mobility of ions upon irradiation. Nyquist plots show semicircles at high frequency due to Li-ion migration through the porous surface of the electrolyte film. A maximum ionic conductivity of 8.28 × 10−4 S cm−1 was obtained with a 120 kGy EB dose and the observed cyclic voltammetry of the irradiated polymer electrolyte suggests it is electrochemically stable.

Reduction of the monomer quantities required for the preparation of radiation-grafted alkaline anion-exchange membranes

Alkaline anion-exchange membranes (AAEM) for alkaline polymer electrolyte fuel cells (APEFC) were successfully prepared using electron beam irradiated poly(ethylene-co-tetrafluoroethylene) precursor films grafted with vinylbenzyl chloride (VBC) monomer. The resulting chloromethyl groups were subsequently reacted with trimethylamine to form quaternary ammonium anion-exchange functional head-groups. The concentration of toxic and expensive VBC, that is required to achieve an optimal level of grafting, was reduced from 100%v/v (undiluted) to 20%v/v by dilution with propan-2-ol and the inclusion of a surfactant. Fuel cell tests using hydrogen and oxygen gave the same peak power densities (164±3mWcm−2) for the AAEMs prepared with both 100%v/v VBC and 20%v/v VBC. This highlights the (desirable) lack of any detrimental effect on performance of the resulting APEFC with the reduction in grafting monomer concentration used for the synthesis of the component AAEM.

Kinetic behaviour of graft copolymerisation of nitrogenous heterocyclic monomer onto EB-irradiated ETFE films

Kinetic behaviour of graft copolymerisation of a nitrogenous heterocyclic monomer, 4-vinylpyridine (4-VP), onto electron beam irradiated poly(ethylene-co-tetra- fluoroethylene) (ETFE) films was investigated in correla- tion with reaction parameters (absorbed dose, monomer concentration and reaction temperature). This was estab- lished by determination of initial polymerisation rate (rp0), characteristic radical recombination rate (c) and delay time (t0). The orders of the dependence of the initial rate of grafting on the absorbed dose and monomer concentration were found to be 2.28 and 3.49, respectively. The effect of temperature was investigated in the range of 50-70 C and the activation energy was determined. The incorporation of poly(4-VP) grafts and the accompanied chemical changes in the grafted ETFE films were monitored using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The results of the present study showed that a quantitative kinetic description for grafting of 4-VP onto ETFE can be established and the degree of grafting can be tuned by controlling the reaction parameters.

An empirical study into the effect of long term storage (−36±2 °C) of electron-beamed ETFE on the properties of radiation-grafted alkaline anion-exchange membranes

The application of alkaline anion-exchange membranes (AAEM) in solid alkaline fuel cells is growing in prominence mainly due to enhanced tolerance to carbon dioxide, compared to alkaline fuel cells containing aqueous electrolytes, and the potential for using non precious metal catalysts. Radiation grafting is a common methodology for the production of functional polymers and membranes. This statistical study examines the synthesis of radiation grafted AAEMs that are formed from electron beam irradiated poly(ethylene-co-tetrafluoroethylene), EB-ETFE. It is shown that EB-ETFE can be cold stored for at least 16 months and still be used to produce ionically conductive AAEMs. The limitations of routine measurements of properties, such as dimensional increases, ion-exchange capacity, water uptakes and ionic conductivities, are also highlighted.

Preparation and characterization of phosphoric acid composite membrane by radiation induced grafting of 4‐vinylpyridine onto poly(ethylene‐co‐tetrafluoroethylene) followed by phosphoric acid doping

AbstractPreparation of phosphoric acid composite membranes by radiation induced grafting of 4‐vinylpyridine (4‐VP) onto electron beam irradiated poly(ethylene‐co‐tetrafluoroethylene) film followed by phosphoric acid doping was investigated. The effect of grafting parameters (monomer concentration, absorbed dose, reaction time, and temperature) on the degree of grafting (G%) in the membrane precursor and its relation with the amount of acid doped was studied. The proton conductivity of the obtained membranes was evaluated in correlation with G% and temperature using ac impedance. Fourier transform infrared, thermal gravimetric analysis, X‐ray diffraction, and universal mechanical tester were used to investigate chemical composition, thermal resistance, structure, and mechanical properties of the membranes, respectively. The membranes of 34 and 49% recorded high proton conductivity in the magnitude of 10‐2 S cm‐1 without humidification. The membranes were also found to have reasonable mechanical integrity together with thermal stability up to 160°C. The obtained membranes are suggested to be less‐water dependent and have potential for testing in high temperature polymer electrolyte membrane fuel cell. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Kinetic investigations of graft copolymerization of sodium styrene sulfonate onto electron beam irradiated poly(vinylidene fluoride) films

Graft copolymerization of sodium styrene sulfonate (SSS) onto electron beam (EB) irradiated poly(vinylidene fluoride) (PVDF) films was investigated to find out a simple preparation process for sulfonic acid proton exchange membranes with respect to monomer concentration, absorbed dose, temperature, film thickness and storage time. The reaction order of the monomer concentration and absorbed dose of grafting was found to be 2.84 and 1.20, respectively. The overall activation energy for graft copolymerization reaction was calculated to be 11.36 kJ/mol. The initial rate of grafting was found to decrease with an increase in the film thickness. The trapped radicals in the irradiated PVDF films remained effective in initiating the reaction without considerable loss in grafting level up to 180 days, when stored under −60 °C. The presence and distribution of polystyrene sulfonate grafts in the obtained membranes were observed by Fourier transform infrared (FTIR) spectroscopic analysis, scanning optical microscope and scanning transmission electron microscopy (STEM) coupled with X-ray energy dispersive (EDX), respectively.

Acid-synergized grafting of sodium styrene sulfonate onto electron beam irradiated-poly(vinylidene fluoride) films for preparation of fuel cell membrane

The role of acid addition in synergizing radiation induced grafting of sodium styrene sulfonate (SSS) onto electron beam-irradiated poly(vinylidene fluoride) (PVDF) films as a single-step route for preparation of proton exchange membranes containing sulfonic acid groups was systematically investigated. The grafting reaction, known for its poor kinetics, was studied using SSS diluted in various solvents and solvent/acid solutions of different concentrations and volumes. The addition of acid solution was found to marvelously synergize the grafting reaction from very low values (e.g., 0.5%) to achieve high degrees (e.g., 65%) of grafting and such synergetic effect depends on the type, concentration and volume of the added acid. The degree of grafting was also found to be function of the monomer concentration and the irradiation dose at constant acid concentration and volume. The obtained membranes were investigated with Fourier transform infrared spectroscopy (FTIR), scanning transmission electron microscopy (STEM), and X-ray diffractometry (XRD). The results of present study reveal that grafting of SSS to levels suitable for fuel cell application onto PVDF film is only possible by adding aqueous acids solution. Moreover, the addition of acid makes this shorter single-step method more economical route for preparation of proton exchange membranes for fuel cells. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Single-step radiation induced grafting for preparation of proton exchange membranes for fuel cell

A single-step method for preparation of sulfonic acid proton exchange membranes (PVDF- g-PSSA) by grafting of sodium styrene sulfonate (SSS) onto electron beam irradiated poly(vinylidene fluoride) (PVDF) was studied. The microstructure of the obtained membranes was characterized using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The properties of the membranes such as water uptake, ionic conductivity and the degree of crystallinity were investigated as a function of ion exchange capacity (IEC). The new method showed to be promising in improving the properties of the membranes and reducing their cost of fabrication.

Thermal and mechanical properties of electron beam irradiated poly(vinyl chloride)/polystyrene blends

AbstractThe effect of electron beam irradiation on the thermal and mechanical properties of poly(vinyl chloride)/polystyrene (PVC/PS) blends and PVC/PS blends containing epoxidized natural rubber (ENR) was studied. The thermogravimetric analysis study showed that the thermal decomposition of the plasticized PVC individual polymer goes through two stages, whereas PS decomposes through one stage. However, the temperature of the maximum rate of reaction (Tmax) of PS is much higher than that for PVC and their blends. Meanwhile, the Tmax was found to increase with increasing PS ratios in the blend. The thermal stability of PVC/PS blends was greatly increased after electron beam irradiation in comparison with unirradiated blends. Moreover, the addition of ENR to PVC/PS increased the thermal stability. On the other hand, the mechanical properties in terms of tensile strength and elongation at break of PVC/PS blends are lower than pure PVC polymer because of the immiscibility. However, the addition of ENR to the PVC/PS (80/20) blend increased the elongation at break from 114 to 321% associated with a small effect on the tensile properties. These behaviors were supported by structure morphology studies observations, which indicate an improvement in the interfacial adhesion between the phases. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers

Physical properties of electron beam irradiated poly(vinyl butyral) composites with carbamate, imidazole, and tetrazolium dye

AbstractFilms of poly(vinyl butyral) composites with triphenyl tetrazolium chloride dye (TTC) and the antioxidant nickel dibutyl dithiocarbamate (NBC) or 2‐mercaptobenzimidazole (MBI) were prepared by the solution casting method using butyl alcohol as a solvent. The effect of various doses of electron beam irradiation (50–200 kGy) on color response, thermal, and mechanical properties were investigated. The color measurements showed that the films of the different composites possessed a high sensitivity to electron beam irradiation, in which the nearly colorless films were changed to deep red color, which can be easily detected by visual observations. In addition, the change in color depends on irradiation dose and the contents of the TTC dye. Moreover, the presence of the antioxidants NBC or MBI has no effect on the development of color. However, PVB/TTC and PVB/TTC/MBI composites showed high regular change in color as a function of irradiation dose. The thermogravimetric analysis used to study the thermal stability indicated that PVB/TTC composites either before or after electron beam irradiation are thermally more stable than neat PVB polymer. The presence of the antioxidants NBC or MBI offered protection to PVB/TTC composites against decomposition or oxidative degradation resulted from irradiation. Blending unirradiated PVB with TTC dye, mixture of TTC and NBC, and mixture of TTC and MBI reduced the tensile strength by 4, 20, and 17% upon blending, respectively. However, the reduction in tensile strength of the entire composite films (∼7% based on the initial value) upon exposure to a dose of 50 kGy is acceptable for practical applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4358–4365, 2006

Formula omitted] NMR characterization of electron beam irradiated vinylidene fluoride–trifluoroethylene copolymers

Electron beam irradiated poly(vinylidene fluoride–trifluoroethylene) [P(VDF–TrFE)] copolymers have been recently shown to exhibit “giant” electrostrictive stains. In this work, 19 F nuclear magnetic resonance (NMR) spectroscopy was used to probe structure of P(VDF–TrFE) copolymers before and after irradiation in order to elucidate the chemistry associated with the development of outstanding electroactive properties. The two-dimensional solution-state 19 F NMR of as-synthesized copolymers reveals strong (∼300 Hz) geminal indirect coupling ( 2J ) and the resulting assignments have some differences from the previous literature. The most frequently occurring sequence containing TrFE is CH 2CF 2CHFCF 2CH 2, followed by CF 2CH 2CHFCF 2CF 2. This reveals a strong preference for the TrFE units to be isolated and a slight preference for the head-to-tail addition. Both sequences contain VDF polymerized in the same direction around the central TrFE monomer unit. Resolution of bonding environments in the insoluble irradiated P(VDF–TrFE) required the use of fast (25 kHz) magic angle spinning (MAS) solid-state 19 F NMR at elevated temperature. Of the resolved peaks formed by irradiation, the side group CF 3CH<, was present in the highest concentration. Such CF 3 pendant groups are likely to reduce crystallinity and thus impact electroactive properties. Also observed was significant formation of CF 3CF 2, which can be either a pendant group or a side group. Several types of CF 3 end groups were observed: CF 3CHF, CF 3CH 2, and CF 3CH. The latter, indicates the formation of some unsaturated bonds upon irradiation. Small concentrations of CHF 2 and CF 2H were also found. Cross-linking is indirectly evidenced by broadening of the NMR spectra of the irradiated material. In the unirradiated copolymer, two conformation; of sequence CH 2CF 2CHFCF 2CH 2 are observed in the solid-state. In the solution-state in the post-irradiated solid-state, only one of these conformations exists.