Displaying publications 1 - 20 of 830 in total

  1. Salleh MH, Glidle A, Sorel M, Reboud J, Cooper JM
    Chem Commun (Camb), 2013 Apr 18;49(30):3095-7.
    PMID: 23396529 DOI: 10.1039/c3cc38228a
    We demonstrate a polymer resonator microfluidic biosensor that overcomes the complex manufacturing procedures required to fabricate traditional devices. In this new format, we show that a gapless light coupling photonic configuration, fabricated in SU8 polymer, can achieve high sensitivity, label-free chemical sensing in solution and high sensitivity biological sensing, at visible wavelengths.
    Matched MeSH terms: Polymers/chemistry*
  2. Chan BQ, Low ZW, Heng SJ, Chan SY, Owh C, Loh XJ
    ACS Appl Mater Interfaces, 2016 04 27;8(16):10070-87.
    PMID: 27018814 DOI: 10.1021/acsami.6b01295
    Shape memory polymers (SMPs) are smart and adaptive materials able to recover their shape through an external stimulus. This functionality, combined with the good biocompatibility of polymers, has garnered much interest for biomedical applications. In this review, we discuss the design considerations critical to the successful integration of SMPs for use in vivo. We also highlight recent work on three classes of SMPs: shape memory polymers and blends, shape memory polymer composites, and shape memory hydrogels. These developments open the possibility of incorporating SMPs into device design, which can lead to vast technological improvements in the biomedical field.
    Matched MeSH terms: Polymers*
  3. Zakaria ND, Yusof NA, Haron J, Abdullah AH
    Int J Mol Sci, 2009 Jan;10(1):354-65.
    PMID: 19333450 DOI: 10.3390/ijms10010354
    Molecular imprinted polymers (MIP) are considered one of the most promising selective and novel separation methods for removal phenolic compound in wastewater treatment. MIP are crosslinked polymeric materials that exhibit high binding capacity and selectivity towards a target molecule (template), purposely present during the synthesis process. In this work MIP were prepared in a bulk polymerization method in acetonitrile using 2,4-dinitrophenol, acrylamide, ethylene glycol dimethacrylate, and benzoyl peroxide as template, functional monomer, cross-linker and initiator, respectively. An adsorption process for removal of nitrophenol using the fabricated MIP was evaluated under various pH and time conditions. The parameters studied for 2,4-dinitrophenol includes adsorption kinetics, adsorption isotherm, and selectivity. The maximum adsorption of nitrophenol by the fabricated MIP was 3.50 mg/g. The adsorption of 2,4-dinitrophenol by the fabricated MIP was found effective at pH 6.0. A kinetics study showed that nitrophenol adsorption follows a second order adsorption rate and the adsorption isotherm data is explained well by the Langmuir model.
    Matched MeSH terms: Polymers/chemical synthesis*; Polymers/chemistry
  4. Shakoor A, Khan AL, Akhter P, Aslam M, Bilad MR, Maafa IM, et al.
    Environ Sci Pollut Res Int, 2021 Mar;28(10):12397-12405.
    PMID: 32651793 DOI: 10.1007/s11356-020-10044-3
    Mixed matrix membranes (MMMs) were fabricated by the hydrothermal synthesis of ordered mesoporous KIT-6 type silica and incorporating in polyimide (P84). KIT-6 and MMMs were characterized to evaluate morphology, thermal stability, surface area, pore volume, and other characteristics. SEM images of synthesized MMMs and permeation data of CO2 suggested homogenous dispersion of mesoporous fillers and their adherence to the polymer matrix. The addition of KIT-6 to polymer matrix improved the permeability of CO2 due to the increase in diffusivity through porous particles. The permeability was 3.2 times higher at 30% loading of filler. However, selectivity showed a slight decrease with the increase in filler loadings. The comparison of gas permeation results of KIT-6 with the well-known MCM-41 revealed that KIT-6 based MMMs showed 14% higher permeability than that of MMMs composed of mesoporous MCM-41. The practical commercial viability of synthesized membranes was examined under different operating temperatures and mixed gas feeds. Mesoporous KIT-6 silica is an attractive additive for gas permeability enhancement without compromising the selectivity of MMMs. Graphical abstract.
    Matched MeSH terms: Polymers*
  5. Yana J, Chiangraeng N, Nimmanpipug P, Lee VS
    J Mol Graph Model, 2021 09;107:107946.
    PMID: 34119952 DOI: 10.1016/j.jmgm.2021.107946
    Conformational search for the most stable geometry connection of 16 sets of polydopamine (PDA) tetramer subunits has been systematically investigated using density functional theory (DFT) calculations. Our results indicated that the more planar subunits are, the more stable they are. This finding is in good agreement with recent experimental observations, which have suggested that PDA are composed of the nearly planar subunits that appear to be stacked together via the π-π interactions to form graphite-like layered aggregates associated with the balance of the intramolecular hydrogen bonds and steric effects from the indole and catechol moieties. Molecular dynamics (MD) simulations of 16 spherical clusters of the tetramer subunits of PDA in the gas and aqueous phase were performed at 298 K and confirmed the stability of supramolecular tetramer aggregates. The complex formation and binding energy of all 16 clusters are very strong although the shapes of the clusters in aqueous solution are not spherical and are very much different from those in the gas phase. The aggregations of all 16 clusters in aqueous solution were also confirmed from the profiles of the Kratky plot and the radius of gyration of all clusters. Our MD results in both gas phase and aqueous solution pointed out that there are high possibilities of aggregations of the 16 kinds of tetramer subunits although the conformations of each tetramer subunit are not flat. In summary, this work brings an insight into the controversial structure of PDA tetramer units and explains some of the important structural features found in the aqueous phase in comparison to the gas phase.
    Matched MeSH terms: Polymers*
  6. Ramachandran H, Iqbal NM, Sipaut CS, Abdullah AA
    Appl Biochem Biotechnol, 2011 Jul;164(6):867-77.
    PMID: 21302147 DOI: 10.1007/s12010-011-9180-8
    Poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-3HV-co-4HB)] terpolymer was produced using Cupriavidus sp. USMAA2-4 via one-step cultivation process through combination of various carbon sources such as 1,4-butanediol or γ-butyrolactone with either 1-pentanol, valeric acid, or 1-propanol. Oleic acid was added to increase the biomass production. The composition of 3HV and 4HB monomers were greatly affected by the concentration of 1,4-butanediol and 1-pentanol. Terpolymers with 3HV and 4HB molar fractions ranging from 2 to 41 mol.% and 5 to 31 mol.%, respectively, were produced by varying the concentration of carbon precursors. The thermal and mechanical properties of the terpolymers containing different proportions of the constituent monomers were characterized using gel permeation chromatography (GPC), DSC, and tensile machine. GPC analysis showed that the molecular weights (M (w)) of the terpolymer produced were within the range of 346 to 1,710 kDa. The monomer compositions of 3HV and 4HB were also found to have great influences on the thermal and mechanical properties of the terpolymer P(3HB-co-3HV-co-4HB) produced.
    Matched MeSH terms: Polymers/metabolism*; Polymers/chemistry*
  7. Abd Rashid MY, Abu Bakar A, Mohd Asri MT, Iskandar SM
    Med J Malaysia, 2004 May;59 Suppl B:135-6.
    PMID: 15468855
    Poly (p-phenylene vinylene) (PPV) was synthesized from p-xylylene bis(tetrahydrothiophenium chloride) using the Wessling route and characterized by Fourier Transform Infra-Red (FTIR) and UV-visible (UV-VIS) spectroscopic techniques. The significance of thermal treatment along with evolution of precursor polymer to polymer PPV was also studied through these spectroscopic techniques. Thermally Stimulated Current (TSC) measurements indicated the presence of crystallization, sulphonium group which occurred through the evolution from precursor polymer to polymer PPV during thermal treatment.
    Matched MeSH terms: Polymers/analysis; Polymers/chemical synthesis*
  8. Kyaw Oo M, Mandal UK, Chatterjee B
    Pharm Dev Technol, 2017 Feb;22(1):2-12.
    PMID: 26616399 DOI: 10.3109/10837450.2015.1116568
    High melting point polymeric carrier without plasticizer is unacceptable for solid dispersion (SD) by melting method. Combined polymer-plasticizer carrier significantly affects drug solubility and tableting property of SD.
    Matched MeSH terms: Polymers
  9. Khaledi H, Olmstead MM, Fukuda T, Ali HM
    Inorg Chem, 2014 Nov 3;53(21):11348-50.
    PMID: 25320842 DOI: 10.1021/ic5019828
    Three isomeric 2[Pd(II)-Ni(II)] metal complexes, derived from indoleninyl meso-substituted dibenzotetraaza[14]annulene, were synthesized. The resulting dimers feature Ni···Ni or, alternatively, Ni···π interactions in staggered or slipped cofacial structures. A remarkable insertion of palladium into two different C-H bonds yielded a 4[Pd(II)-Ni(II)] rectangular complex with dimensions of 8.73 × 10.38 Å.
    Matched MeSH terms: Polymers
  10. Low KS, Muniandy S, Naumov P, Shanmuga Sundara Raj S, Fun HK, Razak IA, et al.
    Acta Crystallogr C, 2000 Mar 15;56(Pt 3):E113-4.
    PMID: 15263222
    Bis(N,N-dimethylthiocarbamoylthio)acetic acid, [(CH(3))(2)NC(=S)S](2)CHC(=O)OH or C(8)H(14)N(2)O(2)S(4), exists as a centrosymmetric hydrogen-bonded dimer [O.O 2.661 (3) A].
    Matched MeSH terms: Polymers
  11. Rahim M, Mas Haris MRH, Saqib NU
    Biophys Rev, 2020 Oct;12(5):1223-1231.
    PMID: 32901426 DOI: 10.1007/s12551-020-00750-0
    In recent years, controlled drug delivery has become an important area of research. Nano-biocomposites can fulfil the necessary requirements of a targeted drug delivery device. This review describes use of polymeric nano-biocomposites in controlled drug delivery devices. Selection of suitable biopolymer and methods of preparation are discussed.
    Matched MeSH terms: Biopolymers; Polymers
  12. Arman HD, Poplaukhin P, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2017 Apr 01;73(Pt 4):488-492.
    PMID: 28435704 DOI: 10.1107/S2056989017003516
    The title compound, {[Cd(C9H11N2S2)2]·C6H7N} n , features two μ2-κ(3)-di-thio-carbamate ligands each of which chelates one Cd(II) atom, via the S atoms, while simultaneously bridging to another via the pyridyl-N atom. The result is a two-dimensional coordination polymer extending parallel to the ab plane with square channels along the b axis. The Cd(II) atom geometry is based on a distorted cis-N2S4 octa-hedron. The 3-methyl-pyridine mol-ecules reside in the channels aligned along the b axis, being held in place by methyl-ene-C-H⋯N(3-methyl-pyridine) and (3-methyl-pyridine)-C-H⋯π(pyrid-yl) inter-actions. Pyridyl-C-H⋯S and di-thio-carbamate-methyl-C-H⋯π(pyrid-yl) inter-actions provide connections between layers along the c axis.
    Matched MeSH terms: Polymers
  13. Wu Y, Liang Y, Mei C, Cai L, Nadda A, Le QV, et al.
    Chemosphere, 2022 Jan;286(Pt 3):131891.
    PMID: 34416587 DOI: 10.1016/j.chemosphere.2021.131891
    Nanocellulose based gas barrier materials have become an increasingly important subject, since it is a widespread environmentally friendly natural polymer. Previous studies have shown that super-high gas barrier can be achieved with pure and hierarchical nanocellulose films fabricated through simple suspension or layer-by-layer technique either by itself or incorporating with other polymers or nanoparticles. Improved gas barrier properties were observed for nanocellulose-reinforced composites, where nanocellulose partially impermeable nanoparticles decreased gas permeability effectively. However, for nanocellulose-based materials, the higher gas barrier performance is jeopardized by water absorption and shape deformation under high humidity conditions which is a challenge for maintaining properties in material applications. Thus, numerous investigations have been done to solve the problem of water absorption in nanocellulose-based materials. In this literature review, gas barrier properties of pure, layer-by-layer and composite nanocellulose films are investigated. The possible theoretical gas barrier mechanisms are described, and the prospects for nanocellulose-based materials are discussed.
    Matched MeSH terms: Polymers
  14. Jamaludin FA, Ab-Kadir MZA, Izadi M, Azis N, Jasni J, Abd-Rahman MS
    PLoS One, 2017;12(11):e0187892.
    PMID: 29136025 DOI: 10.1371/journal.pone.0187892
    Located near the equator, Malaysia is a country with one of the highest lightning densities in the world. Lightning contributes to 70% of the power outages in Malaysia and affects power equipment, automated network systems, causes data losses and monetary losses in the nation. Therefore, consideration of insulator evaluation under lightning impulses can be crucial to evaluate and attempt to overcome this issue. This paper presents a new approach to increase the electrical performance of polymer insulators using a Room Temperature Vulcanisation (RTV) coating. The evaluation involves three different settings of polymer insulator, namely uncoated, RTV type 1, and RTV type 2 upper surface coatings. All the insulators were tested under three different conditions as dry, clean wet and salty under different impulse polarities using the even-rising test method. The voltage breakdown for each test was recorded. From the experiment, it was found that the effectiveness of the RTV coating application became apparent when tested under salty or polluted conditions. It increased the voltage withstand capabilities of the polymer insulator up to 50% from the basic uncoated insulator. Under dry and clean conditions, the RTV coating provided just a slight increase of the breakdown voltage. The increase in voltage breakdown capability decreased the probability of surface discharge and dry band arcing that could cause degradation of the polymeric material housing. The RTV type 1 coating was found to be more effective when performing under a lightning impulse. The findings might help the utility companies improve the performance of their insulators in order to increase power system reliability.
    Matched MeSH terms: Polymers/chemistry*
  15. Kamruzzaman M, Jumaat MZ, Sulong NH, Islam AB
    ScientificWorldJournal, 2014;2014:702537.
    PMID: 25243221 DOI: 10.1155/2014/702537
    In recent decades, the application of fibre-reinforced polymer (FRP) composites for strengthening structural elements has become an efficient option to meet the increased cyclic loads or repair due to corrosion or fatigue cracking. Hence, the objective of this study is to explore the existing FRP reinforcing techniques to care for fatigue damaged structural steel elements. This study covers the surface treatment techniques, adhesive curing, and support conditions under cyclic loading including fatigue performance, crack propagation, and failure modes with finite element (FE) simulation of the steel bridge girders and structural elements. FRP strengthening composites delay initial cracking, reduce the crack growth rate, extend the fatigue life, and decrease the stiffness decay with residual deflection. Prestressed carbon fibre-reinforced polymer (CFRP) is the best strengthening option. End anchorage prevents debonding of the CRRP strips at the beam ends by reducing the local interfacial shear and peel stresses. Hybrid-joint, nanoadhesive, and carbon-flex can also be attractive for strengthening systems.
    Matched MeSH terms: Polymers/standards*; Polymers/chemistry
  16. Izzati WA, Arief YZ, Adzis Z, Shafanizam M
    ScientificWorldJournal, 2014;2014:735070.
    PMID: 24558326 DOI: 10.1155/2014/735070
    Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends.
    Matched MeSH terms: Polymers/analysis; Polymers/chemistry*
  17. Meka VS, Sing MKG, Pichika MR, Nali SR, Kolapalli VRM, Kesharwani P
    Drug Discov Today, 2017 11;22(11):1697-1706.
    PMID: 28683256 DOI: 10.1016/j.drudis.2017.06.008
    Global research on polyelectrolytes at a fundamental and applied level is intensifying because the advantages of sustainability are being accepted in academia and industrial research settings. During recent decades, polyelectrolytes became one of the most attractive subjects of scientific research owing to their great potential in the areas of advanced technologies. Polyelectrolytes are a type of polymer that have multitudinous ionizable functional groups. Ionized polyelectrolytes in solution can form a complex with oppositely charged polyelectrolytes - a polyelectrolyte complex (PEC). The present article provides a comprehensive review on PECs and their classification, theory and characterization, as well as a critical analysis of the current research.
    Matched MeSH terms: Polymers/classification; Polymers/chemistry*
  18. Yousif E, Ahmed DS, Ahmed AA, Hameed AS, Muhamed SH, Yusop RM, et al.
    Environ Sci Pollut Res Int, 2019 Apr;26(10):9945-9954.
    PMID: 30739295 DOI: 10.1007/s11356-019-04323-x
    Although plastic induces environmental damages, almost the consumption of poly(vinyl chloride) never stops increasing. Therefore, this work abstracted by two parts, first, synthesis of Schiff bases 1-4 compounds through the reaction of amino group with appropriate aromatic aldehyde, reaction of PVC with Schiff bases compounds 1-4 in THF to form a new modified PVC-1, PVC-2, PVC-3, and PVC-4. The structures of Schiff bases 1-4 and the modified PVC-1, PVC-2, PVC-3, and PVC-4 have been characterized by different spectroscopic analyses. Second, the influence of introducing 4-amino-1,2,4-triazole as a pendent groups into PVC chain investigated on photostability rules of tests. The modified polymers photostability investigated by observing indices (ICO, Ipo, and IOH), weight loss, UV and morphological studies, and all results obtained indicated that PVC-1, PVC-2, PVC-3 and PVC-4 gave lower growth rate of ICO, IPO, and IOH through UV exposure time. The photostability are given as PVC-4 
    Matched MeSH terms: Polymers/radiation effects*; Polymers/chemistry
  19. Tripathy A, Pramanik S, Cho J, Santhosh J, Osman NA
    Sensors (Basel), 2014;14(9):16343-422.
    PMID: 25256110 DOI: 10.3390/s140916343
    The humidity sensing characteristics of different sensing materials are important properties in order to monitor different products or events in a wide range of industrial sectors, research and development laboratories as well as daily life. The primary aim of this study is to compare the sensing characteristics, including impedance or resistance, capacitance, hysteresis, recovery and response times, and stability with respect to relative humidity, frequency, and temperature, of different materials. Various materials, including ceramics, semiconductors, and polymers, used for sensing relative humidity have been reviewed. Correlations of the different electrical characteristics of different doped sensor materials as the most unique feature of a material have been noted. The electrical properties of different sensor materials are found to change significantly with the morphological changes, doping concentration of different materials and film thickness of the substrate. Various applications and scopes are pointed out in the review article. We extensively reviewed almost all main kinds of relative humidity sensors and how their electrical characteristics vary with different doping concentrations, film thickness and basic sensing materials. Based on statistical tests, the zinc oxide-based sensing material is best for humidity sensor design since it shows extremely low hysteresis loss, minimum response and recovery times and excellent stability.
    Matched MeSH terms: Polymers/chemistry*
  20. Hoque ME, Zainal NH, Syarif J
    Med J Malaysia, 2008 Jul;63 Suppl A:91-2.
    PMID: 19024999
    This study aims at investigating the mechanical properties of the contemporary metallic bone plates determining the effect of their length, width and thickness on the properties and compares with the composite bone plates. Three-points bending test was performed over the stainless steel plates of different length, width and thickness. The test results showed that different plates had different mechanical properties. However, the properties are still much higher than that of particular bones intended to be treated. Therefore, the reported findings strongly encourage developing composite bone plates with biocompatible polymers/fibers that would have modulated properties according to the requirements.
    Matched MeSH terms: Polymers/chemistry
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