Displaying publications 61 - 80 of 306 in total

Abstract:
Sort:
  1. UV-VIS spectral evaluation of CR-39 detector exposed with diagnostic dosage
    Nur Sha'dah Z, Iskandar S, Azhar A, Suhaimi M, Nur Lina R, Halimah M
    Sains Malaysiana, 2014;43:953-958.
    The effects of the X-ray irradiation and chemical etching on the physical and optical properties of cR-39 plastic detectors were investigated for different doses of X-ray. cR-39 detectors were etched in the solution of the 3 M of NaOH after irradiation for revelations of the track. The tracks formed on cR-39 either by irradiated X-ray or due to the effect of environment. The changes in the thickness after exposed have significant decrease in 60 kVp and started to increase in the range of 70 kVp up to 100 kVp due to the formation of oxidation layer on surface by free radicals. The optical band gaps before etching and after etching were determined by using Ultraviolet-visible (uv-Vis) spectroscopy. The optical band gap is attributed to the indirect transition due to its amorphous nature which is significantly decline trend energy in increase of the energy fluence of radiation. The Urbach's energy, is defined as the width of the tail localized states in the forbidden band gap which change increment trend as increase in dose delivered due to the distortion structure of the cR-39 in terms of the electron charges in valences electron hence attributes to the induced modification of angle bond between the neighboring atoms.
    Matched MeSH terms: Polyethylene Glycols
  2. Characterization of the feedstock properties of metal injection-molded WC-Co with palm stearin binder system
    Sri Yulis M. Amin, Norhamidi Muhamad, Khairur Rijal Jamaludin, Fayyaz A, Heng SY
    Sains Malaysiana, 2014;43:123-128.
    Feedstock preparation, as well as its characterization, is crucial in the production of highly sintered parts with minimal defect. The hard metal powder - particularly, cemented carbide (wc-co) used in this study was investigated both physically and thermally to determine its properties before the mixing and injection molding stage. Several analyses were conducted, such as scanning electron microscopy, energy dispersive X-ray diffraction, pycnometer density, critical powder volume percentage (cPvP), as well as thermal tests, such as thermogravimetric analysis and differential scanning calorimetry. On the basis of the CPVP value, the feedstock, consisting of wc-co powder, was mixed with 60% palm stearin and 40% polyethylene at an optimal powder loading, within 2 to 5% lower than the CPVP value. The CPVP spotted value was 65%. The feedstock optimal value at 61% showed good rheological properties (pseudoplastic behavior) with an n value lower than 1, considerably low activation energy and high moldability index. These preliminary properties of the feedstock serve as a benchmark in designing the schedule for the next whole steps (i.e. injection, debinding and sintering processes).
    Matched MeSH terms: Polyethylene
  3. Moldability characteristics of 3 mol% Yttria stabilized Zirconia feedstock for micro-powder injection molding process
    Hafizawati Zakaria, Norhamidi Muhamad, Abu Bakar Sulong, Mord Halim Irwan Ibrahim, Farhana Foudzi
    Sains Malaysiana, 2014;43:129-136.
    Micro powder injection molding (vim) is a promising process that may satisfy the demand on miniaturization parts to micro domain in mass production with low manufacturing cost. Three mol% yttria stabilized zirconia (Ysz) with nano-sized powder and binder system consists of polyethylene glycol (PEG), polymethyl methacrylate (PMMA) and stearic acid (sA) were used. Nano-size powders with higher surface area generally require more binder to form a feedstock. As such, determination of the optimum powder loading of the feedstock for 1UPIM process is important. The rheological characteristics of different YSZ feedstocks with powder loading of 52 53 and 54 vol.% were investigated in terms of flow behavior as a function of viscosity and shear rate. Fairly low values of flow behavior exponent ranging from 025 to 0.39 (n<1) resulted in pseudoplastic flow behavior of the examined Yszfeedstock. The 52 vol.% feedstock exhibited the lowest viscosity resulting in highest activation energy and lowest moldability index of 1.862x10-6, while the 54 vol.% feedstock regardless to its high viscosity, yielded a low activation energy of 4.14 kJImol and high moldability index of 4.59x10-6. Based on rheological properties obtained, a powder loading of 54 vol.% has desirable feedstock characteristics for iumm process and exhibited molding ability for micro detail filling. The relationship between the optimum rheological properties obtained and the actual injection process was also determined. The results showed that the green parts were able to be injected without defects such as short shot or flashing.
    Matched MeSH terms: Polyethylene Glycols
  4. Influence of sintering parameters on the compressive yield strength of stainless steel foams produced by the space holder method
    Tan KT, Norhamidi Muhamad, Muchtar A, Abu Bakar Sulong, Neo MC
    Sains Malaysiana, 2016;45:653-658.
    Metallic foams are a new class of materials that have a great potential to be used in various functional and structural applications. Due to their competitive price compared to aluminium, metallic foams are anticipated to become an alternative material for light-weight structures. In this study, stainless steel foams are fabricated using a powder space holder method. The materials used include stainless steel powder, a novel space holder glycine and binders consisting of palm stearin and of polyethylene (PE). The stainless steel foams are sintered at 1100o C, 1200o C and 1300o C with sintering times of 1, 2 and 3 h, respectively, to investigate the effects of the sintering parameters on the compressive yield strength of the stainless steel foams. The results showed that all of the stainless steel foams produced exhibit the general behaviours of metal foams. The sintering time is the most significant parameter that influences the compressive yield strength of stainless steel foams. Increasing the sintering temperature and sintering time will increase the compressive yield strength. The interaction between the sintering temperature and sintering time is found to be not statistically significant.
    Matched MeSH terms: Polyethylene
  5. Generation, characterization and application of atmospheric pressure plasma jet
    Shrestha R, Subedi DP, Gurung JP, Wong CS
    Sains Malaysiana, 2016;45:1689-1696.
    The development of a non-thermal plasma jet with a capillary configuration working at atmospheric pressure is reported
    in this paper. The plasma jet is powered by a power source with frequency of several kilohertz. The working gas is
    argon. The plasma obtained has been characterized by optical emission spectroscopic measurements and electrical
    measurements of the discharge using voltage and current probes. The electron temperature has been estimated by using
    the modified Boltzmann plot method utilizing the Ar 4p-4s transition. The electron temperatures at various positions
    along the plasma jet length have been obtained and it is found that the electron temperature decreases at position further
    from orifice. The electron density has been estimated from current and voltage measurements using the power balance
    method. The effects of gas flow rate, applied voltage and frequency on the characteristics of the plasma jet have also been
    investigated. The applications of the atmospheric pressure plasma jet (APPJ) developed to modify the surface properties
    of Polyethyleneterephthalate (PET) and polycarbonate (PC) have been tested. Our results showed that the atmospheric
    pressure non-thermal plasma jet can be effectively used to enhance the surface wettability and surface energy of the
    PET and PC. The plasma jet has also been tested for inactivation of prokaryotic cells (Escherichia coli, Staphylococcus
    aureus). In the case of E. coli, better than 4 log10 reduction can be achieved. The effect of plasma jet on the pH of cell
    culture medium has suggested that the plasma species, particularly the electrons, are solely responsible for the effect
    of inactivation of living cells.
    Matched MeSH terms: Polyethylene Terephthalates
  6. Linear low density polyethylene/poly (vinyl alcohol)/kenaf composites: effect of natural weathering on functional group, weight loss characteristics, tensile, morphological and thermal properties
    Pang AL, Azhar Abu Bakar, Hanafi Ismail
    Sains Malaysiana, 2018;47:571-580.
    The development of natural fiber polymer composites is increasing worldwide and in some applications, these composites
    are used at outdoor rendering them exposed to ultra-violet (UV) radiation. The paper investigates the degradation behavior
    of linear low density polyethylene/poly (vinyl alcohol)/kenaf (LLDPE/PVOH/KNF) composites after exposure to different
    natural weathering durations. The composites with KNF loadings of 10, 20 and 40 parts per hundred resin (phr) were
    exposed to natural weathering for 3 months and 6 months, respectively. The weathered composites were characterized by
    Fourier transform infrared (FTIR) spectroscopy, universal testing machine, field emission scanning electron microscopy
    (FESEM) and differential scanning calorimetry (DSC). The FTIR analysis showed an obvious carbonyl peak in composites
    after weathering as an evidence of oxidation. The weight loss percentage of composites increased with respect to exposure
    duration due to higher absorption of UV irradiation. The tensile properties of weathered composites were lower than
    that of control composites and these properties also decreased with increasing exposure duration. FESEM micrographs
    illustrated that composites with longer exposure duration suffered more surface damaged. The crystallinity percentage
    was found to increase with increasing exposure duration.
    Matched MeSH terms: Polyethylene
  7. Effect of permeation enhancers in the mucoadhesive buccal patches of salbutamol sulphate for unidirectional buccal drug delivery
    Prasanth VV, Puratchikody A, Mathew ST, Ashok KB
    Res Pharm Sci, 2014 Jul-Aug;9(4):259-68.
    PMID: 25657797
    The purpose of this work was to study the effect of various permeation enhancers on the permeation of salbutamol sulphate (SS) buccal patches through buccal mucosa in order to improve the bioavailability by avoiding the first pass metabolism in the liver and possibly in the gut wall and also achieve a better therapeutic effect. The influence of various permeation enhancers, such as dimethyl sulfoxide (DMSO), linoleic acid (LA), isopropyl myristate (IPM) and oleic acid (OA) on the buccal absorption of SS from buccal patches containing different polymeric combinations such as hydroxypropyl methyl cellulose (HPMC), carbopol, polyvinyl alcohol (PVA), polyvinyl pyrollidone (PVP), sodium carboxymethyl cellulose (NaCMC), acid and water soluble chitosan (CHAS and CHWS) and Eudragit-L100 (EU-L100) was investigated. OA was the most efficient permeation enhancer increasing the flux greater than 8-fold compared with patches without permeation enhancer in HPMC based buccal patches when PEG-400 was used as the plasticizer. LA also exhibited a better permeation enhancing effect of over 4-fold in PVA and HPMC based buccal patches. In PVA based patches, both OA and LA were almost equally effective in improving the SS permeation irrespective of the plasticizer used. DMSO was more effective as a permeation enhancer in HPMC based patches when PG was the plasticizer. IPM showed maximum permeation enhancement of greater than 2-fold when PG was the plasticizer in HPMC based buccal patches.
    Matched MeSH terms: Polyethylene Glycols
  8. Safety against nephrotoxicity in paclitaxel treatment: Oral nanocarrier as an effective tool in preclinical evaluation with marked in vivo antitumor activity
    Choudhury H, Gorain B, Tekade RK, Pandey M, Karmakar S, Pal TK
    Regul Toxicol Pharmacol, 2017 Dec;91:179-189.
    PMID: 29080846 DOI: 10.1016/j.yrtph.2017.10.023
    Oral paclitaxel (PTXL) formulations freed from cremophor® EL (CrEL) is always in utmost demand by the cancerous patients due to toxicities associated with the currently marketed formulation. In our previous investigation [Int. J. Pharm. 2014; 460:131], we have developed an oral oil based nanocarrier for the lipophilic drug, PTXL to target bioavailability issue and patient compliance. Here, we report in vivo antitumor activity and 28-day sub-chronic toxicity of the developed PTXL nanoemulsion. It was observed that the apoptotic potential of oral PTXL nanoemulsion significantly inhibited the growth of solid tumor (59.2 ± 7.17%; p 
    Matched MeSH terms: Polyethylene Glycols/chemistry
  9. Characterization and solubility study of norfloxacin-polyethylene glycol, polyvinylpyrrolidone and carbopol 974p solid dispersions
    Gorajana A, Kit WW, Dua K
    Recent Pat Drug Deliv Formul, 2015;9(2):167-82.
    PMID: 25714525
    OBJECTIVE: Norfloxacin has a low aqueous solubility which leads to poor dissolution. Keeping this fact in mind the purpose of the present study is to formulate and evaluate norfloxacin solid dispersion.

    METHODS: Solid dispersions were prepared using hydrophilic carriers like polyethylene glycol (PEG) 4000, polyvinylpyrrolidone (PVP) k30 and carbopol 974pNF (CP) in various ratios using solvent evaporation technique. These formulations were evaluated using solubility studies, dissolution studies; Fourier transmitted infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetery (DSC). The influence of polymer type and drug to polymer ratio on the solubility and dissolution rate of norfloxacin was also evaluated.

    RESULTS: FTIR analysis showed no interaction of all three polymers with norfloxacin. The results from XRD and DSC analyses of the solid dispersion preparations showed that norfloxacin existsin its amorphous form. Among the Norfloxacin: PEG solid dispersions, Norfloxacin: PEG 1:14 ratio showed the highest dissolution rate at pH 6.8. For norfloxacin: PVP solid dispersions, norfloxacin: PVP 1:10 ratio showed the highest dissolution rate at pH 6.8. For Norfloxacin: CP solid dispersions, norfloxacin: P 1:2 ratio showed the highest dissolution rate at pH 6.8.

    CONCLUSION: The solid dispersion of norfloxacin with polyethylene glycol (PEG) 4000, polyvinylpyrrolidone (PVP) k30 and carbopol 974p NF (CP), lends an ample credence for better therapeutic efficacy.

    Matched MeSH terms: Polyethylene Glycols/pharmacokinetics; Polyethylene Glycols/chemistry*
  10. Fulltext Effects of different tube potentials and iodine concentrations on image enhancement, contrast-to-noise ratio and noise in micro-CT images: a phantom study
    Abdul Razak HR, Shaffiq Said Rahmat SM, Md Saad WM
    Quant Imaging Med Surg, 2013 Oct;3(5):256-61.
    PMID: 24273743 DOI: 10.3978/j.issn.2223-4292.2013.10.04
    The study aimed to investigate the effects of different tube potentials and concentrations of iodinated contrast media (CM) on the image enhancement, contrast-to-noise ratio (CNR) and noise in micro-computed tomography (µCT) images. A phantom containing of five polyethylene tube was filled with 2 mL of deionized water and iodinated CM (Omnipaque 300 mgI/mL) at four different concentrations: 5, 10, 15, and 20 mol/L, respectively. The phantom was scanned with a µCT machine (SkyScan 1176) using various tube potentials: 40, 50, 60, 70, 80, and 90 kVp, a fixed tube current; 100 µA, and filtration of 0.2 mm aluminum (Al). The percentage difference of image enhancement, CNR and noise of all images, acquired at different kVps and concentrations, were calculated. The image enhancement, CNR and noise curves with respect to tube potential and concentration were plotted and analysed. The highest image enhancement was found at the lowest tube potential of 40 kVp. At this kVp setting, the percentage difference of image enhancement [Hounsfield Unit (HU) of 20 mol/L iodine concentration over HU of deionized water] was 43%. By increasing the tube potential, it resulted with the reduction of HU, where only 17.5% different were noticed for 90 kVp. Across all iodine concentrations (5-20 M), CNR peaked at 80 kVp and then these values showed a slight decreasing pattern, which might be due insufficient tube current compensation. The percentage difference of image noise obtained at 40 and 90 kVp was 72.4%. Lower tube potential setting results in higher image enhancement (HU) in conjunction with increasing concentration of iodinated CM. Overall, the tube potential increment will substantially improve CNR and reduce image noise.
    Matched MeSH terms: Polyethylene
  11. Surface profile of laminated transfemoral socket fabricated with different types of reinforcement materials
    Nik Zainuddin NAM, Abd Razak NA, Ab Karim MS
    Proc Inst Mech Eng H, 2023 Jun;237(6):741-748.
    PMID: 37131337 DOI: 10.1177/09544119231171787
    Composite materials used in the prosthetic and orthotic fields have helped improve the fabrication of sockets. Laminated sockets proved to be stronger than conventional thermoplastic sockets. The internal surface of a laminated socket plays an important role in patient comfort and is influenced by the material used to fabricate the socket. This study analyzes the internal surface profile of five different materials, that is, Dacron felt, fiberglass, Perlon stockinette, polyester stockinette, and elastic stockinette. All sockets were fabricated using an acrylic resin mix with hardener powder at a ratio of 100:3. The internal surface of the sockets was tested using the Mitutoyo SurfTest SJ-210 series for 20 trials. The overall Ra values were 2.318, 2.380, 2.682, 2.722, and 3.750 µm for fiberglass, polyester, Perlon, elastic stockinette, and Dacron felt. Dacron felt yielded the lowest Ra value, thus, producing the smoothest internal surface but requiring high skill and the correct technique during the fabrication of a laminated socket. Fiberglass is considered the best material for the internal surface despite not producing the lowest value individually but overall is the lowest and most consistent, indicating that it is easy to use to laminate prosthetic sockets.
    Matched MeSH terms: Polyethylene Terephthalates*
  12. Degree of conversion and physicomechanical properties of newly developed flowable composite derived from rice husk using urethane dimethacrylate monomer
    Azlisham NAF, Johari Y, Mohamad D, Yhaya MF, Mahmood Z
    Proc Inst Mech Eng H, 2023 Dec;237(12):1339-1347.
    PMID: 38014749 DOI: 10.1177/09544119231208222
    This study evaluated the use of urethane dimethacrylate (UDMA) as a base monomer to prepare the newly developed flowable composite (FC) using nanohybrid silica derived from rice husk in comparison to bisphenol A-glycidyl methacrylate (Bis-GMA) on the degree of conversion and physicomechanical properties. The different loadings of base monomer to diluent monomer were used at the ratio of 40:60, 50:50, and 60:40. The bonding analysis confirmed the presence of nanohybrid silica in the newly developed FC. Independent t-test revealed a statistically significant increase in the degree of conversion, depth of cure and Vickers hardness of the UDMA-based FC, while surface roughness showed comparable results between the two base monomers. In conclusion, UDMA-based FC demonstrated superior performance with 60%-65% conversions, a significantly higher depth of cure exceeding 1 mm which complies with the Internal Standard of Organization 4049 (ISO 4049), and a substantial increase in Vickers hardness numbers compared to Bis-GMA-based FC, making UDMA a suitable alternative to Bis-GMA as a base monomer in the formulation of this newly developed FC derived from rice husk.
    Matched MeSH terms: Polyethylene Glycols
  13. Bioseparation of phycocyanin from Phormidium tergestinum using an aqueous two-phase system
    Tan JS, Abbasiliasi S, Lalung J, Tam YJ, Murugan P, Lee CK
    Prep Biochem Biotechnol, 2021;51(3):260-266.
    PMID: 32876520 DOI: 10.1080/10826068.2020.1808793
    This study aimed at purification of phycocyanin (PC) from Phormidium tergestinum using an aqueous two-phase system (ATPS) comprised of polyethylene glycol (PEG) and salts. The partitioning efficiency of PC in ATPS and the effect of phase composition, pH, crude loading, and neutral salts on purification factor and yield were investigated. Results showed that PC was selectively partitioned toward bottom phase of the system containing potassium phosphate. Under optimum conditions of 20% (w/w) PEG 4000, 10% (w/w) potassium phosphate, 20% (v/v) crude load at pH 7, with addition of 0.5% (w/w) NaCl, PC from P. tergestinum was partially purified up to 5.34-fold with a yield of 87.8%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the molecular weight of PC was ∼19 kDa. Results from this study demonstrated ATPS could be used as a potential approach for the purification of PC from P. tergestinum.
    Matched MeSH terms: Polyethylene Glycols/chemistry
  14. Purification of lipase from Burkholderia metallica fermentation broth in a column chromatography using polymer impregnated resins
    Ng ZJ, Abbasiliasi S, Yew Joon T, Ng HS, Phapugrangkul P, Tan JS
    Prep Biochem Biotechnol, 2023;53(7):872-879.
    PMID: 36594706 DOI: 10.1080/10826068.2022.2158468
    In this work, porous glass beads grafted with polyethylene glycol (PEG) were used as an adsorbent to purify lipase from Burkholderia metallica in column chromatography. The purification parameters viz. salt stability, types and concentrations of PEG and salt, pH of the binding solution, and flow rate were studied to determine the performance of the purification system in an XK16/20 column. The crude lipase was mixed with different types and concentrations of salts 1-5% (w/w) (sodium citrate, potassium citrate, and sodium acetate) and subjected to the column containing the polymeric glass bead. One-variable-at-a-time experimentation revealed that 20% (w/w) PEG 6000 g/mol impregnated glass beads with a binding solution of 5% sodium citrate at pH 7.7, a flow rate of 1.0 mL/min and extraction time of 10 min resulted in the highest purification factor and recovery yield at 3.67 and 88%, respectively. The purified lipase has 55 ∼ 60 kDa molecular mass. The outcome of the study showed PEG could be applied to modify the inert glass beads into polymeric form, providing a biocompatible and mild separation condition for lipase. Thus, PEG could be successfully applied for the purification of lipase from B. metallica fermentation broth using column chromatography.
    Matched MeSH terms: Polyethylene Glycols/chemistry
  15. Fulltext Development of Polysulfone Membrane via Vapor-Induced Phase Separation for Oil/Water Emulsion Filtration
    Barambu NU, Bilad MR, Bustam MA, Huda N, Jaafar J, Narkkun T, et al.
    Polymers (Basel), 2020 Oct 29;12(11).
    PMID: 33137888 DOI: 10.3390/polym12112519
    The discharge of improperly treated oil/water emulsion by industries imposes detrimental effects on human health and the environment. The membrane process is a promising technology for oil/water emulsion treatment. However, it faces the challenge of being maintaining due to membrane fouling. It occurs as a result of the strong interaction between the hydrophobic oil droplets and the hydrophobic membrane surface. This issue has attracted research interest in developing the membrane material that possesses high hydraulic and fouling resistance performances. This research explores the vapor-induced phase separation (VIPS) method for the fabrication of a hydrophilic polysulfone (PSF) membrane with the presence of polyethylene glycol (PEG) as the additive for the treatment of oil/water emulsion. Results show that the slow nonsolvent intake in VIPS greatly influences the resulting membrane structure that allows the higher retention of the additive within the membrane matrix. By extending the exposure time of the cast film under humid air, both surface chemistry and morphology of the resulting membrane can be enhanced. By extending the exposure time from 0 to 60 s, the water contact angle decreases from 70.28 ± 0.61° to 57.72 ± 0.61°, and the clean water permeability increases from 328.70 ± 8.27 to 501.89 ± 8.92 (L·m-2·h-1·bar-1). Moreover, the oil rejection also improves from 85.06 ± 1.6 to 98.48 ± 1.2%. The membrane structure was transformed from a porous top layer with a finger-like macrovoid sub-structure to a relatively thick top layer with a sponge-like macrovoid-free sub-structure. Overall results demonstrate the potential of the VIPS process to enhance both surface chemistry and morphology of the PSF membrane.
    Matched MeSH terms: Polyethylene Glycols
  16. Fulltext An Optimum Fatigue Design of Polymer Composite Compressed Natural Gas Tank Using Hybrid Finite Element-Response Surface Methods
    Kashyzadeh KR, Rahimian Koloor SS, Omidi Bidgoli M, Petrů M, Amiri Asfarjani A
    Polymers (Basel), 2021 Feb 03;13(4).
    PMID: 33546387 DOI: 10.3390/polym13040483
    The main purpose of this research is to design a high-fatigue performance hoop wrapped compressed natural gas (CNG) composite cylinder. To this end, an optimization algorithm was presented as a combination of finite element simulation (FES) and response surface analysis (RSA). The geometrical model was prepared as a variable wall-thickness following the experimental measurements. Next, transient dynamic analysis was performed subjected to the refueling process, including the minimum and maximum internal pressures of 20 and 200 bar, respectively. The time histories of stress tensor components were extracted in the critical region. Furthermore, RSA was utilized to investigate the interaction effects of various polymer composite shell manufacturing process parameters (thickness and fiber angle) on the fatigue life of polymer composite CNG pressure tank (type-4). In the optimization procedure, four parameters including wall-thickness of the composite shell in three different sections of the CNG tank and fiber angle were considered as input variables. In addition, the maximum principal stress of the component was considered as the objective function. Eventually, the fatigue life of the polymer composite tank was calculated using stress-based failure criterion. The results indicated that the proposed new design (applying optimal parameters) leads to improve the fatigue life of the polymer composite tank with polyethylene liner about 2.4 times in comparison with the initial design.
    Matched MeSH terms: Polyethylene
  17. Fulltext Effects on the Properties after Addition of Lithium Salt in Poly(ethylene oxide)/Poly(methyl acrylate) Blends
    Abdul Halim SI, Chan CH, Kressler J
    Polymers (Basel), 2020 Dec 11;12(12).
    PMID: 33322501 DOI: 10.3390/polym12122963
    The studies of phase behavior, dielectric relaxation, and other properties of poly(ethylene oxide) (PEO)/poly(methyl acrylate) (PMA) blends with the addition of lithium perchlorate (LiClO4) were done for different blend compositions. Samples were prepared by a solution casting technique. The binary PEO/PMA blends exhibit a single and compositional-dependent glass transition temperature (Tg), which is also true for ternary mixtures of PEO/PMA/LiClO4 when PEO was in excess with low content of salt. These may indicate miscibility of the constituents for the molten systems and amorphous domains of the systems at room temperature from the macroscopic point of view. Subsequently, the morphology of PEO/PMA blends with or without salt are correlated to the phase behavior of the systems. Phase morphology and molecular interaction of polymer chains by salt ions of the systems may rule the dielectric or electric relaxation at room temperature, which was estimated using electrochemical impedance spectroscopy (EIS). The frequency-dependent impedance spectra are of interest for the elucidation of polarization and relaxation of the charged entities for the systems. Relaxation can be noted only when a sufficient amount of salt is added into the systems.
    Matched MeSH terms: Polyethylene Glycols
  18. Fulltext Thixotropic Supramolecular Pectin-Poly(Ethylene Glycol) Methacrylate (PEGMA) Hydrogels
    Chan SY, Choo WS, Young DJ, Loh XJ
    Polymers (Basel), 2016 Nov 18;8(11).
    PMID: 30974681 DOI: 10.3390/polym8110404
    Pectin is an anionic, water-soluble polymer predominantly consisting of covalently 1,4-linked α-d-galacturonic acid units. This naturally occurring, renewable and biodegradable polymer is underutilized in polymer science due to its insolubility in organic solvents, which renders conventional polymerization methods impractical. To circumvent this problem, cerium-initiated radical polymerization was utilized to graft methoxy-poly(ethylene glycol) methacrylate (mPEGMA) onto pectin in water. The copolymers were characterized by ¹H nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA), and used in the formation of supramolecular hydrogels through the addition of α-cyclodextrin (α-CD) to induce crosslinking. These hydrogels possessed thixotropic properties; shear-thinning to liquid upon agitation but settling into gels at rest. In contrast to most of the other hydrogels produced through the use of poly(ethylene glycol) (PEG)-grafted polymers, the pectin-PEGMA/α-CD hydrogels were unaffected by temperature changes.
    Matched MeSH terms: Polyethylene Glycols
  19. Fulltext Selectivity of Copper by Amine-Based Ion Recognition Polymer Adsorbent with Different Aliphatic Amines
    Othman NAF, Selambakkannu S, Abdullah TAT, Hoshina H, Sattayaporn S, Seko N
    Polymers (Basel), 2019 Dec 02;11(12).
    PMID: 31810361 DOI: 10.3390/polym11121994
    This paper investigates the selectivity of GMA-based-non-woven fabrics adsorbent towards copper ion (Cu) functionalized with several aliphatic amines. The aliphatic amines used in this study were ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA). The non-woven polyethylene/polypropylene fabrics (NWF) were grafted with glycidyl methacrylate (GMA) via pre-radiation grafting technique, followed by chemical functionalization with the aliphatic amine. To prepare the ion recognition polymer (IRP), the functionalized amine GMA-grafted-NWF sample was subjected to radiation crosslinking process along with the crosslinking agent, divinylbenzene (DVB), in the presence of Cu ion as a template in the matrix of the adsorbent. Functionalization with different aliphatic amine was carried out at different amine concentrations, grafting yield, reaction temperature, and reaction time to study the effect of different aliphatic amine onto amine density yield. At a concentration of 50% of amine and 50% of isopropanol, EDA, DETA, TETA, and TEPA had attained amine density around 5.12, 4.06, 3.04, and 2.56 mmol/g-ad, respectively. The amine density yield decreases further as the aliphatic amine chain grows longer. The experimental condition for amine functionalization process was fixed at 70% amine, 30% isopropanol, 60 °C for grafting temperature, and 2 h of grafting time for attaining 100% of grafting yield (Dg). The prepared adsorbents were characterized comprehensively in terms of structural and morphology with multiple analytical tools. An adsorptive removal and selectivity of Cu ion by the prepared adsorbent was investigated in a binary metal ion system. The IRP samples with a functional precursor of EDA, the smallest aliphatic amine had given the higher adsorption capacity and selectivity towards Cu ion. The selectivity of IRP samples reduces as the aliphatic amine chain grows longer, EDA to TEPA. However, IRP samples still exhibited remarkably higher selectivity in comparison to the amine immobilized GMA-g-NWF at similar adsorption experimental conditions. This observation indicates that IRP samples possess higher selectivity after incorporation of the ion recognition imprint technique via the radiation crosslinking process.
    Matched MeSH terms: Polyethylene
  20. Fulltext Well-Dispersed Cellulose Nanofiber in Low Density Polyethylene Nanocomposite by Liquid-Assisted Extrusion
    Yasim-Anuar TAT, Ariffin H, Norrrahim MNF, Hassan MA, Andou Y, Tsukegi T, et al.
    Polymers (Basel), 2020 Apr 17;12(4).
    PMID: 32316664 DOI: 10.3390/polym12040927
    Two different liquid assisted processing methods: internal melt-blending (IMB) and twin-screw extrusion (TWS) were performed to fabricate polyethylene (PE)/cellulose nanofiber (CNF) nanocomposites. The nanocomposites consisted maleic anhydride-grafted PE (PEgMA) as a compatibilizer, with PE/PEgMA/CNF ratio of 97/3/0.5-5 (wt./wt./wt.), respectively. Morphological analysis exhibited that CNF was well-dispersed in nanocomposites prepared by liquid-assisted TWS. Meanwhile, a randomly oriented and agglomerated CNF was observed in the nanocomposites prepared by liquid-assisted IMB. The nanocomposites obtained from liquid-assisted TWS exhibited the best mechanical properties at 3 wt.% CNF addition with an increment in flexural strength by almost 139%, higher than that of liquid-assisted IMB. Results from this study indicated that liquid feeding of CNF assisted the homogenous dispersion of CNF in PE matrix, and the mechanical properties of the nanocomposites were affected by compounding method due to the CNF dispersion and alignment.
    Matched MeSH terms: Polyethylene
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links