Displaying publications 101 - 120 of 571 in total

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  1. Fallahiarezoudar E, Ahmadipourroudposht M, Yusof NM, Idris A, Ngadiman NHA
    Polymers (Basel), 2017 Nov 06;9(11).
    PMID: 30965883 DOI: 10.3390/polym9110584
    Valvular dysfunction as the prominent reason of heart failure may causes morbidity and mortality around the world. The inability of human body to regenerate the defected heart valves necessitates the development of the artificial prosthesis to be replaced. Besides, the lack of capacity to grow, repair or remodel of an artificial valves and biological difficulty such as infection or inflammation make the development of tissue engineering heart valve (TEHV) concept. This research presented the use of compound of poly-l-lactic acid (PLLA), thermoplastic polyurethane (TPU) and maghemite nanoparticle (γ-Fe₂O₃) as the potential biomaterials to develop three-dimensional (3D) aortic heart valve scaffold. Electrospinning was used for fabricating the 3D scaffold. The steepest ascent followed by the response surface methodology was used to optimize the electrospinning parameters involved in terms of elastic modulus. The structural and porosity properties of fabricated scaffold were characterized using FE-SEM and liquid displacement technique, respectively. The 3D scaffold was then seeded with aortic smooth muscle cells (AOSMCs) and biological behavior in terms of cell attachment and proliferation during 34 days of incubation was characterized using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and confocal laser microscopy. Furthermore, the mechanical properties in terms of elastic modulus and stiffness were investigated after cell seeding through macro-indentation test. The analysis indicated the formation of ultrafine quality of nanofibers with diameter distribution of 178 ± 45 nm and 90.72% porosity. In terms of cell proliferation, the results exhibited desirable proliferation (109.32 ± 3.22% compared to the control) of cells over the 3D scaffold in 34 days of incubation. The elastic modulus and stiffness index after cell seeding were founded to be 22.78 ± 2.12 MPa and 1490.9 ± 12 Nmm², respectively. Overall, the fabricated 3D scaffold exhibits desirable structural, biological and mechanical properties and has the potential to be used in vivo.
  2. Akbari S, Mahmood SM, Tan IM, Ling OL, Ghaedi H
    Polymers (Basel), 2017 Oct 04;9(10).
    PMID: 30965788 DOI: 10.3390/polym9100480
    The viscosity of four new polymers was investigated for the effect of aging at high temperature, with varying degrees of salinity and hardness. The four sulfonated based polyacrylamide co-polymers were FLOCOMB C7035; AN132 VHM; SUPERPUSHER SAV55; and THERMOASSOCIATIF copolymers. All polymer samples were aged at 80 °C for varying times (from zero to at least 90 days) with and without isobutyl alcohol (IBA) as an antioxidant. To see the effect of divalent ions on the polymer solution viscosity, parallel experiments were performed in a mixture of CaCl₂-NaCl of the same ionic strength as 5 wt % NaCl. The polymers without IBA showed severe viscosity reduction after aging for 90 days in both types of preparation (5 wt % NaCl or CaCl₂-NaCl). In the presence of IBA, viscosity was increased when aging time was increased for 5 wt % NaCl. In CaCl₂-NaCl, on the other hand, a viscosity reduction was observed as aging time was increased. This behavior was observed for all polymers except AN132 VHM.
    Matched MeSH terms: Polymers
  3. Akbari S, Mahmood SM, Tan IM, Ghaedi H, Ling OL
    Polymers (Basel), 2017 Nov 27;9(12).
    PMID: 30965947 DOI: 10.3390/polym9120647
    This research aims to test four new polymers for their stability under high salinity/high hardness conditions for their possible use in polymer flooding to improve oil recovery from hydrocarbon reservoirs. The four sulfonated based polyacrylamide co-polymers were FLOCOMB C7035; SUPERPUSHER SAV55; THERMOASSOCIATIF; and AN132 VHM which are basically sulfonated polyacrylamide copolymers of AM (acrylamide) with AMPS (2-Acrylamido-2-Methylpropane Sulfonate). AN132 VHM has a molecular weight of 9⁻11 million Daltons with 32 mol % degree of sulfonation. SUPERPUSHER SAV55 mainly has about 35 mol % sulfonation degree and a molecular weight of 9⁻11 million Daltons. FLOCOMB C7035, in addition, has undergone post-hydrolysis step to increase polydispersity and molecular weight above 18 million Daltons but it has a sulfonation degree much lower than 32 mol %. THERMOASSOCIATIF has a molecular weight lower than 12 million Daltons and a medium sulfonation degree of around 32 mol %, and also contains LCST (lower critical solution temperature) type block, which is responsible for its thermoassociative characteristics. This paper discusses the rheological behavior of these polymers in aqueous solutions (100⁻4500 ppm) with NaCl (0.1⁻10 wt %) measured at 25 °C. The effect of hardness was investigated by preparing a CaCl₂-NaCl solution of same ionic strength as the 5 wt % of NaCl. In summary, it can be concluded that the rheological behavior of the newly modified co-polymers was in general agreement to the existing polymers, except that THERMOASSOCIATIF polymers showed unique behavior, which could possibly make them a better candidate for enhanced oil recovery (EOR) application in high salinity conditions. The other three polymers, on the other hand, are better candidates for EOR applications in reservoirs containing high divalent ions. These results are expected to be helpful in selecting and screening the polymers for an EOR application.
    Matched MeSH terms: Polymers
  4. Abdul Rahman NH, Chieng BW, Ibrahim NA, Abdul Rahman N
    Polymers (Basel), 2017 Nov 07;9(11).
    PMID: 30965890 DOI: 10.3390/polym9110588
    The aim was to explore the utilization of tea leaf waste fibers (TLWF) as a source for the production of cellulose nanocrystals (CNC). TLWF was first treated with alkaline, followed by bleaching before being hydrolyzed with concentrated sulfuric acid. The materials attained after each step of chemical treatments were characterized and their chemical compositions were studied. The structure analysis was examined by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). From FTIR analysis, two peaks at 1716 and 1207 cm-1-which represent C=O stretching and C⁻O stretching, respectively-disappeared in the spectra after the alkaline and bleaching treatments indicated that hemicellulose and lignin were almost entirely discarded from the fiber. The surface morphology of TLWF before and after chemical treatments was investigated by scanning electron microscopy (SEM) while the dimension of CNC was determined by transmission electron microscopy (TEM). The extraction of CNC increased the surface roughness and the crystallinity index of fiber from 41.5% to 83.1%. Morphological characterization from TEM revealed the appearance of needle-like shaped CNCs with average diameter of 7.97 nm. The promising results from all the analyses justify TLWF as a principal source of natural materials which can produce CNC.
  5. Awang N, Jaafar J, Ismail AF
    Polymers (Basel), 2018 Feb 15;10(2).
    PMID: 30966230 DOI: 10.3390/polym10020194
    Void-free electrospun SPEEK/Cloisite15A® densed (SP/e-spunCL) membranes are prepared. Different loadings of Cloisite15A® (0.10, 0.15, 0.20, 0.25 and 0.30 wt %) are incorporated into electrospun fibers. The physico-chemical characteristics (methanol permeability, water uptake and proton conductivity) of the membranes are observed. Thermal stability of all membranes is observed using Thermal Gravimetry Analysis (TGA). The thrree stages of degradation range between 163.1 and 613.1 °C. Differential Scanning Calorimetry (DSC) is used to study the wettability of the membranes. SP/e-spunCL15 shows the lowest freezing bound water of 15.27%, which contributed to the lowest methanol permeability. The non-freezing bound water that proportionally increased with proton conductivity of SP/e-spunCL15 membrane is the highest, 10.60%. It is suggested that the electrospinning as the fabricating method has successfully exfoliated the Cloisite in the membrane surface structure, contributing to the decrease of methanol permeability, while the retained water has led to the enhancement of proton conductivity. This new fabrication method of SP/e-spunCL membrane is said to be a desirable polymer electrolyte membrane for future application in direct methanol fuel cell field.
    Matched MeSH terms: Polymers
  6. Ayu RS, Khalina A, Harmaen AS, Zaman K, Jawaid M, Lee CH
    Polymers (Basel), 2018 Oct 25;10(11).
    PMID: 30961112 DOI: 10.3390/polym10111187
    In this study, polybutylene succinate (PBS) was blended with five types of modified tapioca starch to investigate the effect of modified tapioca starch in PBS blends for food packaging by identifying its properties. Tensile and flexural properties of blends found deteriorated for insertion of starch. This is due to poor interface, higher void contents and hydrolytic degradation of hydrophilic starch. FTIR results show all starch/PBS blends are found with footprints of starch except OH stretching vibration which is absent in B40 blends. Besides, Broad O⁻H absorption in all specimens show that these are hydrogen bonded molecules and no free O⁻H bonding was found. SEM testing shows good interfacial bonding between PBS and starch except E40 blends. Therefore, poor results of E40 blends was expected. In TGA, a slightly weight loss found between 80 to 100 °C due to free water removal. Apart from this, insertion of all types of starch reduces thermal stability of blend. However, high crystallinity of starch/PBS blend observed better thermal stability but lower char yield. Starch A and B blends are suggested to be used as food wrap and food container materials while starch D blend is suitable for grocery plastic bags according to observed results.
    Matched MeSH terms: Polymers
  7. Rizal S, Ikramullah, Gopakumar DA, Thalib S, Huzni S, Abdul Khalil HPS
    Polymers (Basel), 2018 Nov 28;10(12).
    PMID: 30961241 DOI: 10.3390/polym10121316
    Natural fiber composites have been widely used for various applications such as automotive components, aircraft components and sports equipment. Among the natural fibers Typha spp have gained considerable attention to replace synthetic fibers due to their unique nature. The untreated and alkali-treated fibers treated in different durations were dried under the sun for 4 h prior to the fabrication of Typha fiber reinforced epoxy composites. The chemical structure and crystallinity index of composites were examined via FT-IR and XRD respectively. The tensile, flexural and impact tests were conducted to investigate the effect of the alkali treated Typha fibers on the epoxy composite. From the microscopy analysis, it was observed that the fracture mechanism of the composite was due to the fiber and matrix debonding, fiber pull out from the matrix, and fiber damage. The tensile, flexural and impact strength of the Typha fiber reinforced epoxy composite were increased after 5% alkaline immersion compared to untreated Typha fiber composite. From these results, it can be concluded that the alkali treatment on Typha fiber could improve the interfacial compatibility between epoxy resin and Typha fiber, which resulted in the better mechanical properties and made the composite more hydrophobic. So far there is no comprehensive report about Typha fiber reinforcing epoxy composite, investigating the effect of the alkali treatment duration on the interfacial compatibility, and their effect on chemical and mechanical of Typha fiber reinforced composite, which plays a vital role to provide the overall mechanical performance to the composite.
  8. Ibrahim S, Othman N, Sreekantan S, Tan KS, Mohd Nor Z, Ismail H
    Polymers (Basel), 2018 Nov 01;10(11).
    PMID: 30961141 DOI: 10.3390/polym10111216
    Natural rubber is one of the most important renewable biopolymers used in many applications due to its special properties that cannot be easily mimicked by synthetic polymers. To sustain the existence of natural rubber in industries, modifications have been made to its chemical structure from time to time in order to obtain new properties and to enable it to be employed in new applications. The chemical structure of natural rubber can be modified by exposure to ultraviolet light to reduce its molecular weight. Under controlled conditions, the natural rubber chains will be broken by photodegradation to yield low-molecular-weight natural rubber. The aim of this work was to obtain what is known as liquid natural rubber via photodegradation, with titanium dioxide nanocrystals as the catalyst. Titanium dioxide, which was firstly synthesized using the sol⁻gel method, was confirmed to be in the form of an anatase, with a size of about 10 nm. In this work, the photodegradation was carried out in latex state and yielded low-molecular-weight natural rubber latex of less than 10,000 g/mol. The presence of hydroxyl and carbonyl groups on the liquid natural rubber (LNR) chains was observed, resulting from the breaking of the chains. Scanning electron microscopy of the NR latex particles showed that titanium dioxide nanocrystals were embedded on the latex surface, but then detached during the degradation reaction.
  9. Nirmal U
    Polymers (Basel), 2018 Sep 25;10(10).
    PMID: 30960991 DOI: 10.3390/polym10101066
    The current work is an attempt to reduce friction coefficient of the treated betelnut fibre reinforced polyester (T-BFRP) composites by aging them in twelve different solutions with different kinematic viscosities. The test will be performed on a pin on disc (POD) wear test rig using different applied loads (5⁻30 N), different sliding distances (0⁻6.72 km) at sliding speed of 2.8 m/s subjected to a smooth stainless steel counterface (AISI-304). Different orientations of the fibre mats such as anti-parallel (AP) and parallel (P) orientations subjected to the rotating counterface will be considered. The worn surfaces were examined through optical microscopy imaging and it was found that the aged specimens had significantly lower damages as compared to neat polyester (NP) and the unaged samples. Besides, P-O samples revealed lower friction coefficients as compared to AP-O, i.e., reduction was about 24.71%. Interestingly, aging solutions with lower kinematic viscosities revealed lower friction coefficients of the aged T-BFRP composites when compared to the ones aged in higher kinematic viscosities.
  10. Teo KT, Hassan A, Gan SN
    Polymers (Basel), 2018 Dec 11;10(12).
    PMID: 30961299 DOI: 10.3390/polym10121374
    Palm fatty acid distillate (PFAD), is a by-product of the crude palm oil refining process. It comprises mainly of free fatty acids-around 45% palmitic and 33% oleic acids-as the major components. Ultra-violet (UV) curable urethane acrylate (UA) oligomers could be synthesized from PFAD, by the following procedure. A hydroxyl terminated macromer was first prepared by reacting PFAD with a mixture of isophthalic acid, phthalic anhydride, neopentagylcol (NPG), and pentaerythritol. The macromer was then reacted with 2-hydroxylethylacrylate (2HEA) and toluene diisocynate (TDI) to generate a resin, containing acrylate side chains for UV curable application. A series of UA resins were prepared by using 15, 25, 45, 55, and 70% of PFAD, respectively. The UA resin has Mw in the range of 3,200 to 27,000. They could be cured by UV irradiation at an intensity of 225 mW/cm². Glass transition temperature (Tg) of the cured film was measured by differential scanning calorimeter (DSC), and hardness of the film was determined by a pendulum hardness tester, according to American Society for Testing and Materials (ASTM)4366. The resins were used in a wood-coating application. All of the cured films showed good adhesion, hardness, and chemical resistance except for the one using the 70% PFAD, which did not cure properly.
  11. Rani E, Mohshim SA, Ahmad MZ, Goodacre R, Alang Ahmad SA, Wong LS
    Polymers (Basel), 2019 Mar 25;11(3).
    PMID: 30960545 DOI: 10.3390/polym11030561
    There is an increasing demand for lithography methods to enable the fabrication of diagnostic devices for the biomedical and agri-food sectors. In this regard, scanning probe lithography methods have emerged as a possible approach for this purpose, as they are not only convenient, robust and accessible, but also enable the deposition of "soft" materials such as complex organic molecules and biomolecules. In this report, the use of polymer pen lithography for the fabrication of DNA oligonucleotide arrays is described, together with the application of the arrays for the sensitive and selective detection of Ganoderma boninense, a fungal pathogen of the oil palm. When used in a sandwich assay format with DNA-conjugated gold nanoparticles, this system is able to generate a visually observable result in the presence of the target DNA. This assay is able to detect as little as 30 ng of Ganoderma-derived DNA without any pre-amplification and without the need for specialist laboratory equipment or training.
    Matched MeSH terms: Polymers
  12. Challabi AJH, Chieng BW, Ibrahim NA, Ariffin H, Zainuddin N
    Polymers (Basel), 2019 Mar 13;11(3).
    PMID: 30960466 DOI: 10.3390/polym11030482
    The effectiveness of superheated steam (SHS) as an alternative, eco-friendly treatment method to modify the surface of pineapple leaf fiber (PALF) for biocomposite applications was investigated. The aim of this treatment was to improve the interfacial adhesion between the fiber and the polymer. The treatment was carried out in an SHS oven for different temperatures (190⁻230 °C) and times (30⁻120 min). Biocomposites fabricated from SHS-treated PALFs and polylactic acid (PLA) at a weight ratio of 30:70 were prepared via melt-blending techniques. The mechanical properties, dimensional stability, scanning electron microscopy (SEM), and X-ray diffraction (XRD) for the biocomposites were evaluated. Results showed that treatment at temperature of 220 °C for 60 min gave the optimum tensile properties compared to other treatment temperatures. The tensile, flexural, and impact properties as well as the dimensional stability of the biocomposites were enhanced by the presence of SHS-treated PALF. The SEM analysis showed improvement in the interfacial adhesion between PLA and SHS-treated PALF. XRD analysis showed an increase in the crystallinity with the addition of SHS-PALF. The results suggest that SHS can be used as an environmentally friendly treatment method for the modification of PALF in biocomposite production.
    Matched MeSH terms: Polymers
  13. Jaganathan SK, Mani MP, Khudzari AZM
    Polymers (Basel), 2019 Apr 01;11(4).
    PMID: 30960571 DOI: 10.3390/polym11040586
    The ultimate goal in tissue engineering is to fabricate a scaffold which could mimic the native tissue structure. In this work, the physicochemical and biocompatibility properties of electrospun composites based on polyurethane (PU) with added pepper mint (PM) oil and copper sulphate (CuSO₄) were investigated. Field Emission Electron microscope (FESEM) study depicted the increase in mean fiber diameter for PU/PM and decrease in fiber diameter for PU/PM/CuSO₄ compared to the pristine PU. Fourier transform infrared spectroscopy (FTIR) analysis revealed the formation of a hydrogen bond for the fabricated composites as identified by an alteration in PU peak intensity. Contact angle analysis presented the hydrophobic nature of pristine PU and PU/PM while the PU/PM/CuSO₄ showed hydrophilic behavior. Atomic force microscopy (AFM) analysis revealed the increase in the surface roughness for the PU/PM while PU/PM/CuSO₄ showed a decrease in surface roughness compared to the pristine PU. Blood compatibility studies showed improved blood clotting time and less toxic behavior for the developed composites than the pristine PU. Finally, the cell viability of the fabricated composite was higher than the pristine PU as indicated in the MTS assay. Hence, the fabricated wound dressing composite based on PU with added PM and CuSO₄ rendered a better physicochemical and biocompatible nature, making it suitable for wound healing applications.
  14. Kamaruzzaman NF, Pina MF, Chivu A, Good L
    Polymers (Basel), 2018 May 12;10(5).
    PMID: 30966555 DOI: 10.3390/polym10050521
    The treatment of skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge, partly due to localization of the bacteria inside the host's cells, where antimicrobial penetration and efficacy is limited. We formulated the cationic polymer polyhexamethylene biguanide (PHMB) with the topical antibiotic nadifloxacin and tested the activities against intracellular MRSA in infected keratinocytes. The PHMB/nadifloxacin nanoparticles displayed a size of 291.3 ± 89.6 nm, polydispersity index of 0.35 ± 0.04, zeta potential of +20.2 ± 4.8 mV, and drug encapsulation efficiency of 58.25 ± 3.4%. The nanoparticles killed intracellular MRSA, and relative to free polymer or drugs used separately or together, the nanoparticles displayed reduced toxicity and improved host cell recovery. Together, these findings show that PHMB/nadifloxacin nanoparticles are effective against intracellular bacteria and could be further developed for the treatment of skin and soft tissue infections.
    Matched MeSH terms: Polymers
  15. Gaaz TS, Kadhum AAH, Michael PKA, Al-Amiery AA, Sulong AB, Nassir MH, et al.
    Polymers (Basel), 2017 Jun 06;9(6).
    PMID: 30970887 DOI: 10.3390/polym9060207
    A halloysite nanotubes⁻polyvinyl alcohol⁻polyvinylpyrrolidone (HNTs⁻PVA⁻PVP) composite has been investigated for a quite long time aiming at improving the physico⁻chemical characterization of HNTs. In this work, HNTs⁻PVA⁻PVP composite were prepared based on a unique procedure characterized by crosslinking two polymers with HNTs. The composite of two polymers were modified by treating HNTs with phosphoric acid (H₃PO₄) and by using malonic acid (MA) as a crosslinker. The composite was also treated by adding the dispersion agent sodium dodecyl sulfate (SDS). The HNTs⁻PVA⁻PVP composite shows better characteristics regarding agglomeration when HNTs is treated in advance by H₃PO₄. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), brunauer⁻emmett⁻teller (BET), size distribution, and atomic force microscopy (AFM) are used to characterize the physio-chemical properties of the composite. FTIR shows additional peaks at 2924.29, 1455.7, and 682.4 cm-1 compared to the neat HNTs due to adding MA. Despite that, the XRD spectra do not show a significant difference, the decrease in peak intensity could be attributed to the addition of semi-crystalline PVA and the amorphous PVP. The images taken by TEM and FESEM show the possible effects of MA on the morphology and internal feature of HNTs⁻PVA⁻PVP composite treated by MA by showing the deformation of the matrix. The BET surface area increased to 121.1 m²/g compared to the neat HNTs at 59.1 m²/g. This result, the second highest recorded result, is considered a breakthrough in enhancing the properties of HNTs⁻PVA⁻PVP composite, and treatment by MA crosslinking may attribute to the size and the number of the pores. The results from these techniques clearly showed that a significant change has occurred for treated HNTs⁻PVA⁻PVP composite where MA was added. The characterization of HNTs⁻PVA⁻PVP composite with and without treating HNTs and using crosslinker may lead to a better understanding of this new composites as a precursor to possible applications in the dentistry field.
    Matched MeSH terms: Polymers
  16. Chieng BW, Ibrahim NA, Then YY, Loo YY
    Polymers (Basel), 2017 Jun 02;9(6).
    PMID: 30970882 DOI: 10.3390/polym9060204
    A renewable resource, epoxidized jatropha oil (EJO), was used as a green plasticizer and added to poly(lactic acid) (PLA). EJO was compounded into PLA at different contents. The addition of 3 wt % EJO to the PLA demonstrates significant improvement in flexibility, which leads to a percentage increase of about 7000% in elongation at break. This tensile result was confirmed by surface morphology analysis with clear proof of plastic deformation in EJO-plasticized PLA. EJO imparts a good heat stabilization effect. Thermal stability of PLA was enhanced upon addition of EJO, which is due to their good interaction and plasticizer dispersion within the PLA matrix. This EJO-plasticized PLA has wide applications in various industries, such as packaging of food and non-food products.
  17. Haniffa MACM, Ching YC, Chuah CH, Kuan YC, Liu DS, Liou NS
    Polymers (Basel), 2017 May 01;9(5).
    PMID: 30970841 DOI: 10.3390/polym9050162
    Non-isocyanate polyurethane (NIPU) was prepared from Jatropha curcas oil (JCO) and its alkyd resin via curing with different diamines. The isocyanate-free approach is a green chemistry route, wherein carbon dioxide conversion plays a major role in NIPU preparation. Catalytic carbon dioxide fixation can be achieved through carbonation of epoxidized derivatives of JCO. In this study, 1,3-diaminopropane (DM) and isophorone diamine (IPDA) were used as curing agents separately. Cyclic carbonate conversion was catalyzed by tetrabutylammonium bromide. After epoxy conversion, carbonated JCO (CJCO) and carbonated alkyd resin (CC-AR) with carbonate contents of 24.9 and 20.2 wt %, respectively, were obtained. The molecular weight of CJCO and CC-AR were determined by gel permeation chromatography. JCO carbonates were cured with different amine contents. CJCO was blended with different weight ratios of CC-AR to improve its characteristics. The cured NIPU film was characterized by spectroscopic techniques, differential scanning calorimetry, and a universal testing machine. Field emission scanning electron microscopy was used to analyze the morphology of the NIPU film before and after solvent treatment. The solvent effects on the NIPU film interfacial surface were investigated with water, 30% ethanol, methyl ethyl ketone, 10% HCl, 10% NaCl, and 5% NaOH. NIPU based on CCJO and CC-AR (ratio of 1:3) with IPDA crosslink exhibits high glass transition temperature (44 °C), better solvent and chemical resistance, and Young's modulus (680 MPa) compared with the blend crosslinked with DM. Thus, this study showed that the presence of CC-AR in CJCO-based NIPU can improve the thermomechanical and chemical resistance performance of the NIPU film via a green technology approach.
  18. Udenni Gunathilake TMS, Ching YC, Ching KY, Chuah CH, Abdullah LC
    Polymers (Basel), 2017 Apr 29;9(5).
    PMID: 30970839 DOI: 10.3390/polym9050160
    Extensive employment of biomaterials in the areas of biomedical and microbiological applications is considered to be of prime importance. As expected, oil based polymer materials were gradually replaced by natural or synthetic biopolymers due to their well-known intrinsic characteristics such as biodegradability, non-toxicity and biocompatibility. Literature on this subject was found to be expanding, especially in the areas of biomedical and microbiological applications. Introduction of porosity into a biomaterial broadens the scope of applications. In addition, increased porosity can have a beneficial effect for the applications which exploit their exceptional ability of loading, retaining and releasing of fluids. Different applications require a unique set of pore characteristics in the biopolymer matrix. Various pore morphologies have different characteristics and contribute different performances to the biopolymer matrix. Fabrication methods for bio-based porous materials more related to the choice of material. By choosing the appropriate combination of fabrication technique and biomaterial employment, one can obtain tunable pore characteristic to fulfill the requirements of desired application. In our previous review, we described the literature related to biopolymers and fabrication techniques of porous materials. This paper we will focus on the biomedical and microbiological applications of bio-based porous materials.
    Matched MeSH terms: Biopolymers; Polymers
  19. Hosen MA, Alengaram UJ, Jumaat MZ, Sulong NHR, Darain KMU
    Polymers (Basel), 2017 May 19;9(5).
    PMID: 30970858 DOI: 10.3390/polym9050180
    Reinforced concrete (RC) structures require strengthening for numerous factors, such as increased load, modification of the structural systems, structural upgrade or errors in the design and construction stages. The side near-surface mounted (SNSM) strengthening technique with glass fiber-reinforced polymer (GFRP) bars is a relatively new emerging technique for enhancing the flexural capacities of existing RC elements. Nine RC rectangular beams were flexurally strengthened with this technique and tested under four-point bending loads until failure. The main goal of this study is to optimize the structural capacity of the RC beams by varying the amount of strengthening reinforcement and bond length. The experimental test results showed that strengthening with SNSM GFRP bars significantly enhanced the flexural responses of the specimens compared with the control specimen. The first cracking and ultimate loads, energy absorption capacities, ductility and stiffness were remarkably enhanced by the SNSM technique. It was also confirmed that the bond length of the strengthened reinforcement greatly influences the energy absorption capacities, ductility and stiffness. The effect of the bond length on these properties is more significant compared to the amount of strengthening reinforcement.
    Matched MeSH terms: Polymers
  20. Jaganathan SK, Mani MP, Ismail AF, Ayyar M
    Polymers (Basel), 2017 May 04;9(5).
    PMID: 30970842 DOI: 10.3390/polym9050163
    The objective of this work is to characterize and investigate the blood compatibility of polyurethane (PU)/mustard oil composites fabricated using electrospinning technique. The fabricated scaffold was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and contact angle measurements. The activated partial thromboplastin time (APPT), prothrombin time (PT) and the hemolytic assay were done to investigate the blood compatibility of the developed composites. The SEM results revealed that the fiber diameter of the composites (761 ± 123 nm) was reduced compared to pristine PU control. The interaction between PU and mustard oil was confirmed by FTIR as evident through the shifting of peaks. The fabricated composites depicted hydrophobic behavior as insinuated by the increase in contact angle measurements. PU/mustard composites displayed improved crystallinity as confirmed by TGA. Atomic force micrographs suggested that developed PU/mustard oil composites showed an increase in the surface roughness (Ra) compared to pure PU. The Ra of pure PU was observed to be 723 nm but for the fabricated PU/mustard oil composite the Ra was found to be 1298 nm (Ra). The hemolytic index value for pure PU and fabricated composites was observed to be 2.73% and 1.15% indicating that developed composites showed a non-hemolytic behavior signifying the safety of the composites with red blood cells. Hence the newly developed composites with improved physicochemical and blood compatibility properties may be considered as a potential candidate for fabricating cardiac patches and grafts.
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