Structural investigations of poly(ethylene terephthalate)- graft-polystyrene copolymer films

Structural investigations of poly(ethylene terephthalate)-graft-polystyrene (PET-g-PS) films prepared by radiation-induced grafting of styrene onto commercial poly- (ethylene terephthalate) (PET) films were carried out by FTIR, X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The variation in the degree of crystallinity and the thermal characteristics of PETfilms was correlated withthe amount of polystyrene grafted therein (i.e., the degree of grafting). The heat of melting was found to be a function of PET crystalline fraction in the grafted films. The grafting is found to take place by incorporation of amorphous polystyrene grafts in the entire noncrystalline (amorphous) region of the PET films and at the surface of the crystallites. This results in a decrease in the degree of crystallinity with the increase in the degree of grafting, attributed to the dilution of PET crystalline structure with the amorphous polystyrene, without almost any disruption in the inherent crystallinity

Gamma radiation-induced graft copolymerization of styrene onto poly(ethyleneTerephthalate) films

Gamma radiation-induced graft copolymerization of styrene onto poly(ethylene terephthalate) (PET) films was studied using simultaneous irradiation technique. The effects of grafting conditions on the degree of grafting were investigated. The grafting conditions include monomer concentration, irradiation dose, dose rate, and the type of solvent. Moreover, the effect of the addition of crosslinking agents [i.e., divinylbenzene (DVB) and triallyl cyanurate (TAC)] having various concentrations were also investigated. The degree of grafting was found to be greatly dependent on the grafting conditions. Of the three diluents employed, methylene chloride was found to drastically enhance the degree of grafting. The order of dependence of the initial rate of grafting on the monomer concentration was found to be 2.2. The grafted PET films were identified by FTIR spectroscopy and characterized by X-ray diffraction (XRD)

Water and charge transport models in proton exchange membranes: An overview

Recently, the significant role of water management in affecting the performance and durability of proton exchange membrane fuel cell (PEMFC) has been subjective to an intensive research to understand water transport phenomena which is marked by two processes: water adsorption and water diffusion. Various mathematical models have been developed to address both processes on a different basis. This article briefly reviews various water transport models in a comparative manner to have a better understanding on the role of water hydration with respect to membrane structure and transport mechanism, in affecting the proton transport in the membranes. A discussion on the validity and reliability of the models for describing the water management is also presented. The limitations that are required to be overcome to design new materials meeting the new trends of membranes development for fuel cell are also highlighted

Preparation of proton exchange membrane by radiation-induced grafting method : Grafting of styrene onto poly(ethylene tetrafluoroethylene) copolymer films

Radiation induced grafting of styrene onto poly(ethylene-tetrafluoroethylene) (ETFE) copolymer film was carried out to prepare graft copolymer (ETFE-g-polystyrene) that can host sulfonic acid groups and form proton exchange membrane for polymer electrolyte fuel cell (PEFC). The effect of monomer concentration and type of solvent on the degree of grafting was investigated. The formation of graft copolymer film was confirmed by FTIR spectrum analysis

The preparation and characterization of chitosan/poly (vinyl alcohol) blended films : mechanical, thermal and surface investigations

In this study, blends of chitosan (CS) and polyvinyl alcohol (PVA) (CS/PVA) having various proportions were prepared and characterized by universal mechanical tester, the differential scanning calorimetry (DSC) and contact angle measurements. Studying the mechanical properties of the films showed that blending improved the tensile strength, which increased with increasing PVA content up to 40% while the elongation% at break of the blends was decreased compared to that of the pure components. The obtained results of DSC suggested that some interaction between chitosan and PVA mostly took place. Static water contact angle measurements showed an improvement in the wettability of the obtained films

Optimization of batch conditions for the removal of boron by Amberlite IR743

This study is aimed at optimizing the treatment parameters in boron adsorption using a commercial resin, Amberlite IRA 743, via response surface methodology (RSM). The effect of adsorbent dosage, pH and initial boric acid concentration were optimized using RSM in order to obtain high removal efficiencies at low adsorbent dosage and pH levels and high concentrations. The central composite design (CCD) was used to generate the experimental design. The experiments were conducted in a batch process according to the experimental design obtained. The analysis of variance (ANOVA) was performed to obtain a statistical validation of regression models and to study the interaction between treatment parameters. The optimum conditions recommended by the developed model for 100% removal efficiency, was at adsorbent dosage, pH and initial boron concentration of 51g/L, pH 7 and 40mg/L

Removal of boron using glucamine containing nano and micro fibrous ion-exchange materials

Fibrous lon-exchangers me rather promising with regard to their good sorption capacity mainly because of their large surface area to volume ratio. This study is aimed at establishing a comparison between nano- and micro- fibrous materials for boron removal. The materials chosen for this study were prepared via radiation induced grafting to attach an epoxy containing monomer group and subsequently functionalized with N-methylghicamine. The performances of the nano- and micro ion-exchangers were compared on a batch basis to determine the boron removal percentage The parameters investigated were adsorbent dosage, time. pH and initial boric acid concentration. Based on the results obtained nano-fibrous ion-exchangers were found to perform better than micro-fibrous 1011- exchangers

Enterprise architecture “As-Is” analysis for competitive advantage

In the telecommunication market, it is essential to ensure that the infrastructure and resources of the internet service provider can adapt and grow. In contrast, provide the best quality of data services and offering the best packages for their customers. It is essential to ensure that an internet service provider company remain competitive and agile so that it can provide better products and services promptly to the market. At iiNET, raising awareness of how having an enterprise-wide understanding and view of how the business processes run and all the existing technology within the organisation is vital in ensuring their adaptability and growth in the telecom industry. This paper discusses the challenges which IINET is currently facing and how an enterprise architecture solution is proposed to provide iiNET with the strategic advantage it needs to overcome those challenges. The existing EA frameworks are discussed and analysed to select the best fit for iiNET's EA solution. Finally, the "As-Is" architecture at iiNET is explained as the findings for this EA implementation phase

Immobilization of candida rugosa lipase on aminated polyvinyl benzyl chloride-grafted nylon-6 microfibers

This paper demonstrates a simplified procedure for the preparation of a nylon-6 microfibers based support for the immobilization of Candida rugosa lipase via covalent attachment to enhance the stability and reusability of lipase. The preparation of the support was done by radiation induced graft copolymerization (RIGC) of vinyl benzyl chloride (VBC) onto nylon-6 microfibers followed by amination with ethanolamine to facilitate the immobilization of lipase. Fourier transfer infra red (FTIR) and scanning electron microscope (SEM) were used to study the chemical and physical changes following grafting, amination and immobilization. Response surface methodology (RSM) was applied for the optimization of lipase immobilization on the aminated microfibers. The optimization parameters were incubation time, pH, and lipase concentration. Moreover, this study investigated the effect of temperature, pH, and storage stability and reusability on the lipase in its immobilized and free forms. The developed model from RSM showed an R2 value of 0.9823 and P-value < 0.001 indicating that the model is significant. The optimum temperatures for both immobilized and free lipases were 45 °C, whereas the best pH values for lipase activity were at pH 8 and pH 7, respectively. This study also identifies values for KM and Vmax for both immobilized and free lipase accordingly. Based on the results, immobilized lipase had significantly improved the stability and reusability of lipase compared to that in free forms

Strong improvement of permeability and rejection performance of graphene oxide membrane by engineered interlayer spacing

Advanced membranes fabricated from multilayer/laminated graphene oxide (GO) are promising in water treatment applications as they provide very high flux and excellent rejection of various water pollutants. However, these membranes have limited viability, and suffer from instabilities and swelling due to the hydrophilic nature of GO. In this work, the permeability and rejection performance of laminated GO membranes were improved via functionalization with ethylenediamine (EDA) and polyethyleneimine (PEI). The membranes are fabricated via the pressure-assembly stacking technique, and their structure is well characterized. The performance, rejection, and stability of the fabricated functionalized GO membranes were evaluated. Pillaring the GO layers using diamine and polyamine resulted in exceptionally high water permeability of 113 L/m2h (LMH) compared to only 28 LMH for the pristine GO membrane while simultaneously satisfying high rejection of multivalent salts of 79.4, 35.4, and 19.6 % for Na2SO4, MgCl2, and NaCl, respectively. The results obtained indicate that proper functionalization of GO provides a roadmap for the potential commercialization of such advanced membranes in water treatment applications.</p