scholarly journals Electrospun Magnetic Nanocellulose–Polyethersulfone-Conjugated Aspergillus oryzae Lipase for Synthesis of Ethyl Valerate

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 972
Author(s):  
Nurul Hidayah Hussin ◽  
Roswanira Abdul Wahab ◽  
Nursyafiqah Elias ◽  
Adikwu Gowon Jacob ◽  
Mohamad Hamdi Zainal-Abidin ◽  
...  
Keyword(s):  
Aspergillus Oryzae ◽  
Covalent Immobilization ◽  
Attenuated Total Reflection ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Viable Option ◽  
Electrospinning Technique ◽  
X Ray ◽  
Pes Membrane ◽  
Thermal Stability Of

A novel greener MNC/PES membrane was developed through an electrospinning technique for lipase immobilization to catalyze the synthesis of ethyl valerate (EV). In this study, the covalent immobilization of Aspergillus oryzae lipase (AOL) onto an electrospun nanofibrous membrane consisting of magnetic nanocellulose (MNC) and polyethersulfone (PES) to produce EV was statistically optimized. Raman spectroscopy, Fourier-transform infrared spectroscopy: attenuated total reflection, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, thermal gravimetric analysis (TGA), and differential thermal gravimetric (DTG) of MNC/PES-AOL demonstrated that AOL was successfully immobilized onto the fibers. The Taguchi design-assisted immobilization of AOL onto MNC/PES fibers identified that 1.10 mg/mL protein loading, 4 mL reaction volume, 250 rpm stirring rate, and 50 °C were optimal to yield 72.09% of EV in 24 h. The thermal stability of MNC/PES-AOL was improved by ≈20% over the free AOL, with reusability for up to five consecutive esterification cycles while demonstrating an exceptional half-life of 120 h. Briefly, the electrospun MNC/PES fibers that immobilized AOL showed promising applicability in yielding relatively good EV levels. This study suggests that using MNC as fillers in a PES to improve AOL activity and durability for a longer catalytic process could be a viable option.

The Utilization of Recycled Newspaper in the Production of Cellulose Microfiber

2016 ◽  
Vol 1133 ◽  
pp. 644-648 ◽  
Author(s):  
Mohamad Azuwa Mohamed ◽  
Wan Norharyati Wan Salleh ◽  
Juhana Jaafar ◽  
Ahmad Fauzi Ismail
Keyword(s):  
Electron Microscopy ◽  
Cost Effective ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reinforcement Material ◽  
Cellulose Microfibers ◽  
Thermal Stability Of ◽  
Scanning Electron

Cellulose microfibers (CMF) were produced by utilizing recycled newspaper paper (RNP) as starting material. This approach is considered as green since recycling newspaper leads to the environment preservation and also cost-effective. The effect on the structural properties of cellulose produced at different stage of pretreatment were investigated by using Fourier transform infrared (FTIR), Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Thermal gravimetric analysis (TGA). The FTIR and SEM demonstrate that the hemicellulose and lignin was successfully removed from the structure of the CMF. XRD and TGA results revealed that the different step of pretreatment was increased the crystallinity and thermal stability of CMF increased gradually. The improvement in CMF crystallinity has improved its thermal properties which is important in the field of reinforcement material.

Synthesis, Structure, and Characterization of La1−xBax (0 ≤ x ≤ 1)

1992 ◽  
Vol 271 ◽  
Author(s):  
Joseph E. Sunstrom ◽  
Susan M. Kauzlarich
Keyword(s):  
Magnetic Susceptibility ◽  
Powder Diffraction ◽  
Single Phase ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Temperature Dependent ◽  
X Ray ◽  
Early Transition Metal ◽  
Arc Melting

ABSTRACTThe compounds La1−xBaxTiO3 (0 ≤ × ≤ 1) have been prepared by arc melting stoichiometric amounts of LaTiO3 and BaTiO3. Single phase samples can be made for the entire stoichiometry range. The polycrystalline samples have been characterized by thermal gravimetric analysis, X-ray powder diffraction, and temperature dependent magnetic susceptibility. This series of compounds has been studied as a possible candidate for an early transition metal superconductor.

scholarly journals The Thermal Properties of Polyurethane/Neoprene Blends on Prosthetic Foot

2020 ◽  
Vol 990 ◽  
pp. 106-110
Author(s):  
Mohd Zulkifli Mohamad Noor ◽  
Mohamad Anas Mohd Azmi ◽  
Mohd Shaiful Zaidi Mad Desa ◽  
Mohd Bijarimi Mat Piah ◽  
Azizan Ramli
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Low Cost ◽  
Decomposition Temperature ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Prosthetic Foot ◽  
Reinforced Polymer ◽  
New Material ◽  
Thermal Stability Of

Neoprene reinforced polymer has become an attraction in current research and development of new material blend. In this invention, neoprene was chosen to be enhance to polyurethane because of their superior properties that possess extraordinary mechanical, electrical, optical and thermal properties on prosthetic foot. In this research, polyurethane was chosen due to good rigidity, easy processing and low cost. The reinforcement polyurethane with neoprene is expected to improve the properties of polyurethane. The objective of this research was conducted to investigate the effect of neoprene contents on thermal properties of polyurethane reinforced neoprene on prosthetic foot. The effect of neoprene on thermal properties neoprene reinforced polyurethane was analysed in term of its thermal stability by thermal gravimetric analysis (TGA). Moreover, the visual of small topographic details on the surface of polyurethane/neoprene blends will be examined by scanning electron microscope (SEM). Based on result, the thermal properties show the great enhancement at high neoprene contents which is 1.0wt%. The thermal stability of polyurethane reinforced neoprene improves when the temperature where decomposition starts to occurs are higher than decomposition temperature of pure polyurethane. Then, thermal conductivity of polyurethane shows the great improvement after the addition of neoprene. Lastly, the smooth surface and visible of sheets pattern on surface represent the present of neoprene disperse into polymer that enhance brittleness. Thus, the presence of neoprene has clearly enhanced the thermal stability of the polyurethane. Table 1 shows formulation of neoprene and polyurethane.

scholarly journals Recovery of cutting oil from wastewater by pervaporation process using natural clay modified PVA membrane

2019 ◽  
Vol 80 (12) ◽  
pp. 2404-2411
Author(s):  
D. Unlu
Keyword(s):  
Morphological Analysis ◽  
Poly Vinyl Alcohol ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Natural Clay ◽  
Feed Mixture ◽  
Feed Concentration ◽  
Feed Temperature ◽  
Thermal Stability Of ◽  
Clay Kaolin

Abstract In this study, the pervaporative dehydration of the cutting oil ‘diethylene glycol’ (DEG) through a hydrophilic PVA membrane was investigated at various operation temperatures in the range of 333–363 K with a feed mixture containing 0.5–2.0 wt% water. The pervaporation (PV) performance of poly(vinyl alcohol) (PVA) is enhanced by the addition of natural clay kaolin into the pristine membrane. The thermal stability of the membranes was analyzed by thermal gravimetric analysis (TGA). The morphological analysis of the membranes was performed by scanning electron microscope (SEM). Separation success was determined by calculation of flux, selectivity, and PSI. These values were investigated as functions of the clay amount, feed concentration and feed temperature. The obtained results show that PV is an effective method for recycling waste cutting oil from wastewater.

Synthesis and characterization of diaminomaleonitrile-functionalized polystyrene grafts for application in pervaporation separation

2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Hamada Abdel-Razik
Keyword(s):  
Chemical Structure ◽  
Thermal Characteristics ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Optimum Conditions ◽  
Scanning Calorimetry ◽  
Phenol Water ◽  
Pervaporation Separation ◽  
Thermal Stability Of

AbstractSynthesis, characterization and application of diaminomaleonitrile (DAMN)-functionalized polystyrene grafts were studied. Dibenzoyle peroxide (BP) was used as an initiator. Optimum conditions for grafting were found to be c(DAMN) = 0.5 M, c(BP) = 0.016 M, θ = 85 °C and t = 4 h. Water uptake of the polystyrene graft membranes was found to increase with the increase of the grafting yield. The chemical structure, thermal characteristics and thermal stability of the obtained membranes were investigated by means of FTIR spectroscopy, differential scanning calorimetry, and thermal gravimetric analysis. Polystyrene graft membrane with the degree of grafting of up to 96 % was found to be useful for the pervaporation separation of phenol/water mixtures.

Thermo-Oxidative Degradation of Thick-Walled Rubber Materials Studied by IR-Technique and Computed X-Ray Tomography Scanning

1990 ◽  
Vol 63 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Bengt Mattson ◽  
Bengt Stenberg ◽  
Sture Persson ◽  
Erik Östman
Keyword(s):  
Oxidative Degradation ◽  
Attenuated Total Reflection ◽  
Low Permeability ◽  
Conventional System ◽  
X Ray ◽  
Oxidative Aging ◽  
Aging Properties ◽  
Thermal Stability Of ◽  
Tomography Scanning ◽  
Thermo Oxidative Degradation

Abstract Natural rubber cylinders vulcanized with two different systems, TMTD, which is an efficient vulcanizing system (EV system) and S/CBS, which is a conventional system, have been studied with respect to thermo-oxidative aging gradients, by the ATR-IR-technique (attenuated total-reflection infrared spectroscopy), computed x-ray tomography scanning and swelling. Observed aging processes are dominated by the formation of an oxidized layer whose low permeability to oxygen protects the interior of the material from oxidative aging processes as long as it is intact. The time to the formation of the oxidized layer is the major reason for the differences in the aging gradients. The oxidized layer is formed rapidly in the conventional system, whereas the formation is inhibited by dithiocarbamates in the EV system. Oxygen therefore diffuses into the EV materials, giving deeper oxidative aging than in the conventional materials at the same temperature. The conclusion drawn from the results of this study is that an earlier formation of an oxidized layer is advantageous with respect to thermo-oxidative aging of the bulk. Although it must be stated that, due to the better thermal stability of an EV system and to the poor mechanical properties of an oxidized layer, no objection is here raised to the accepted view that an EV system has superior aging properties.

Preparation and Properties of Silane-Terminated Poly(urethane-Imide)

2013 ◽  
Vol 690-693 ◽  
pp. 1577-1580
Author(s):  
Xiao Xi Hu ◽  
Yun Wang
Keyword(s):  
Thermal Stability ◽  
Water Resistance ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Silane Coupling ◽  
Ft Ir ◽  
And Storage ◽  
Thermal Stability Of

A serious of silane-terminated poly (urethane-imide) (Si-PUI) was synthesized via prepolymer method using polycarbonatediols (PCDL), 2,4-tolylene diisocyanate (TDI), 4,4'-Oxydiphthalic Anhydride (ODPA) and silane coupling agent KH-550. The structure of the products was characterized by FT-IR. The thermal properties were measured by thermal gravimetric analysis (TGA). The thermal mechanical behavior was investigated by dynamic mechanical analysis (DMA).The mechanical characteristic was measured by tensile tests. The water absorption (Wa) was also been tested. With the imide content increasing, the thermal stability, tensile strength and storage modulus of poly (urethane-imide) improve significantly, and the glass transition temperature rises. The introduction of silanes improves the water resistance and further enhances the thermal stability of poly (urethane-imide).

Synthesis of Novel Carbon Spheres and Study on Graphitization Process

2013 ◽  
Vol 634-638 ◽  
pp. 2293-2296
Author(s):  
Ai Li Ma ◽  
Cheng Qian Li ◽  
Wu Qing Du ◽  
Jie Chang
Keyword(s):  
High Temperature ◽  
Microwave Plasma ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Carbon Spheres ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cvd Method ◽  
Graphitization Degree ◽  
Scanning Electron

In this paper, carbon spheres were synthesized by CVD method. These carbon spheres exhibit diameters of about 200 nm. Thermal gravimetric analysis indicated the good stability in high temperature of the carbon spheres. The products were treated by microwave plasma and high temperature vacuum heat treatments respectively. The products were characterized by X-ray diffraction, Raman spectroscopy and Field Emission Scanning Electron Microscope. The study indicated that the original products, with perfect morphology and low graphitization degree, were converted to crystal. The different techniques were considered for the influence on the graphitization degree.

Study on the Preparation and Properties of EVA-G-PU/OMMT Nanocomposites

2010 ◽  
Vol 123-125 ◽  
pp. 247-250
Author(s):  
Yu Qing Zhang ◽  
Yu Xin He ◽  
Li Zhang ◽  
Jun Xian Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Clay Nanocomposites ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
Thermal Stabilities ◽  
X Ray ◽  
Transmission Electron ◽  
New Type

A new type of EVA-g-PU/OMMT nanocomposites was synthesized through the method of chemical modification and melt intercalation. FTIR testing showed that the PU prepolymer was grafted on EVA main chains successfully. The structures of EVA-g-PU/OMMT nanocomposites were characterized by X-ray diffraction (XRD) and by high-resolution transmission electron microscopy (HRTEM). The enhanced storage modulus of EVA-g-PU/OMMT nanocomposites was characterized by dynamic mechanical analysis (DMA). The thermal stabilities of EVA/clay nanocomposites were also studied by thermal gravimetric analysis (TGA). Mechanical testing showed that the tensile strength and tear strength of EVA-g-PU/OMMT nanocomposites were far superior to pure EVA.

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