Displaying publications 81 - 100 of 317 in total

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  1. Bacterial cellulose film coating as drug delivery system: physicochemical, thermal and drug release properties
    Mohd Cairul Iqbal Mohd Amin, Abadi Gumah Abadi, Naveed Ahmad, Haliza Katas, Jamia Azdina Jamal
    Sains Malaysiana, 2012;41:561-568.
    There has been an increasing interest in the use of natural materials as drug delivery vehicles due to their biodegradability, biocompatibility and ready availability. These properties make bacterial cellulose (BC), from nata de coco, a promising biopolymer for drug delivery applications. The aim of this study was to investigate the film-coating and drug release properties of this biopolymer. Physicochemical, morphological and thermal properties of BC films were studied. Model tablets were film coated with BC, using a spray coating technique, and in vitro drug release studies of these tablets were investigated. It was found that BC exhibited excellent ability to form soft, flexible and foldable films without the addition
    of any plasticizer. They were comparable to Aquacoat ECD (with plasticizer) in tensile strength, percentage elongation and elasticity modulus. Differential scanning calorimetry (DSC) BC showed a high Tg value indicating thermally stability of films. These results suggest that BC can be used as novel aqueous film-coating agent with lower cost and better film forming properties than existing film-coating agents.
    Matched MeSH terms: Tensile Strength
  2. Pull-out and tensile strength properties of two selected tropical trees
    Normaniza Osman, Mohamad Nordin Abdullah, Che Hassandi Abdullah
    Sains Malaysiana, 2011;40:1123-1127.
    A bioengineering technique is gradually being used as an alternative for slope stabilisation design. The effect of vegetation on soil strength, particularly in terms of root reinforcement aspects has therefore become a major interest. However, there is a lack of documentation on the root mechanical properties available especially in Malaysia. In this study, both pull-out and tensile strength of two tropical trees namely Leucaena leucocephala and Acacia mangium were investigated on different stem sizes. L. leucocephala performs the higher pullout strength than A. mangium. The results also show that pullout resistance is much affected by the root than the shoot profiles. In terms of tensile strength, the tensile strength decreases with increasing root diameter, implying the finer root diameter contribute to the higher tensile strength. In both parameters, L. leucocephala exhibits the highest value. The study suggests that L. leucocephala has an added value as a good potential slope plant for slope stabilization work as it exhibits outstanding root mechanical properties. Interestingly, the results also showed that the pullout force was much affected by the tensile strength. It can be concluded that some root and shoot properties do have a great impact on root mechanical properties such as tensile and pullout strengths.
    Matched MeSH terms: Tensile Strength
  3. Effect of different drying methods on the morphology, crystallinity, swelling ability and tensile properties of nata de coco
    Norhayati Pa'e, Nur Idayu Abd Hamid, Norzieana Khairuddin, Khairul Azly Zahan, Kok FS, Bazlul Mobin Siddique, et al.
    Sains Malaysiana, 2014;43:767-773.
    Nata de coco or bacterial cellulose produced by Acetobacter xylinum is a unique type of biocellulose. It contains more than 90% of water. Dried nata was preferred compared to wet form since it is more convenient and portable with stable properties. Therefore, drying process is necessary in order to produce dried nata de coco. Drying method is a key factor that influenced the properties of dried nata de coco produced. The aim of this study was to investigate the effect of different drying methods on morphology, crystallinity, swelling ability and tensile strength of dried nata de coco. Nata de coco samples were dried using three physical drying methods such as oven, tray dryer or freeze dryer until it achieved 3-5% moisture content. Obviously, the three drying techniques produced web-like structured nata de coco and quite similar crystallinity which was in range between 87 and 89%. Freeze dried sample showed the largest swelling capacity and tensile strength which was found to be 148 MPa. Different drying method gave different properties of nata de coco. Therefore, the present work proposed the most suitable drying method can be utilized based on the properties of end product needed.
    Matched MeSH terms: Tensile Strength
  4. Effects of silica on the formation of epoxidised natural rubber/polyvinyl chloride membrane
    Nazwa Jon, Ibrahim Abdullah, Rizafizah Othaman
    Sains Malaysiana, 2013;42:469-473.
    The presence of pores plays an important role for many membrane processes especially in ultrafiltration and microfiltration. Epoxidised natural rubber (ENR)/polyvinyl chloride (PVC) membranes filled with two types of silica fillers were prepared via simultaneous solvent exchange and evaporation of solvent technique. Two types of silica, i.e. microsilica (microcrystalline
    silica powder) and nanosilica (generated from tetraethoxysilane (TEOS)) were used. The chemical composition, morphology and mechanical stability of the membranes were studied. Both types of silica showed good interaction with the membrane matrix. The formation of pores depended on the size of silica particles added. Microsilica produced large pores while insitu generated nanosilica produced nanosized pores. The mechanical properties of membrane improved with the addition
    of silica. The tensile strength increased from 10.6 MPa to 17.8 MPa and 14.5 MPa for nanosilica and microsilica filled membrane while the tensile modulus increased from 1.6 MPa to 3.8 MPa and 3.4 MPa, respectively. Thus, both types of silica acted as a filler as well as pore forming agent for the ENR/PVC membrane.
    Matched MeSH terms: Tensile Strength
  5. Fulltext Effect of Preparation Methods on the Tensile, Morphology and Solar Energy Conversion Efficiency of RGO/PMMA Nanocomposites
    Kee SY, Munusamy Y, Ong KS, Lai KC
    Polymers (Basel), 2017 Jun 18;9(6).
    PMID: 30970908 DOI: 10.3390/polym9060230
    In this study, reduced graphene oxide (RGO)/polymethyl methacrylate (PMMA) nanocomposites were prepared by employing in situ polymerization and solution blending methods. In terms of mechanical properties, RGO loading increased the Young's modulus but decreased the elongation at break for RGO/PMMA nanocomposites. Tensile strength for solution blended RGO/PMMA nanocomposites increased after adding 0.5 wt % RGO, which was attributed to the good dispersion of RGO in the nanocomposites as evidenced from SEM and TEM. Solar energy conversion efficiency measurement results showed that the optimum concentration of RGO in the RGO/PMMA nanocomposites was found to be 1.0 wt % in order to achieve the maximum solar energy conversion efficiency of 25%. In the present study, the solution blended nanocomposites exhibited better overall properties than in situ polymerized nanocomposites owing to the better dispersion of RGO in solution blending. These findings would contribute to future work in search of higher conversion efficiency using nanocomposites.
    Matched MeSH terms: Tensile Strength
  6. Mechanical, thermal and chemical resistance of epoxidized natural rubber toughened polylactic acid blends
    Mat Uzir Wahi, Azman Hassan, Akos Noel Ibrahim, Nurhayati Ahmad Zawawi, Kunasegeran K
    Sains Malaysiana, 2015;44:1615-1623.
    Polylactic acid (PLA)/Epoxidized natural rubber (ENR-50) blends were prepared by melt extrusion followed by injection
    molding to fabricate the test samples. The effect of ENR-50 loadings on the morphological, mechanical, chemical
    resistance and water absorption properties of the blends were studied using standard methods. The toughness of the
    blend improved with ENR loading up to 20 wt. % but flexural and tensile strength decreased. The balanced mechanical
    properties were obtained at 20 wt. % ENR-50 loading. SEM showed good distribution and increased ENR particle size
    as ENR content increased from 10 to 30 wt. %. The differential scanning calorimeter (DSC) showed a steady drop in
    crystallization temperature (Tc
    ) as ENR content increases while the glass transition temperature (Tg
    ) remained unchanged.
    Water absorption was observed to increase with ENR loadings. Increase in ENR content was also observed to reduce the
    chemical resistance of the blends.
    Matched MeSH terms: Tensile Strength
  7. Mechanical properties of alumina trihydrate filled polypropylene/ethylene propylene diene monomer composites for cable applications
    Reza Hashemi Farzad, Azman Hassan, M. Jawaid, M.A.M. Piah
    Sains Malaysiana, 2013;42:801-810.
    Polymeric materials such as polypropylene (PP), polyethylene (PE) and ethylene propylene diene monomer (EPDM) are widely used as insulators for cable applications. We investigated the effect of alumina trihydrate (ATH) loading on the mechanical properties of PP/EPDM blend. Preliminary study showed that PP/EPDM (60:40) was the optimum composition. ATH filled PP/EPDM composites was prepared by using twin screw extruder. In this study, the tensile properties and hardness of the composites were evaluated. The tensile modulus and hardness increased while elongation at break and tensile strength decreased with increasing ATH content. Scanning electron microscope was used to study the morphology of ATH in PP/EPDM blend.
    Matched MeSH terms: Tensile Strength
  8. The effects of maleic anhydride grafted PP (MAPP) on the mechanical properties of injection moulded kenaf/cnts/pp composites
    Zakaria Razak, Abu Bakar Sulong, Norhamidi Muhamad, Che Hassan Che Haron, Mohd Khairol Fadzly Md Radzi, Dulina Tholibon, et al.
    Sains Malaysiana, 2018;47:1285-1291.
    Composite materials have increasingly become crucial in manufacturing engineering products and producing commodity
    materials in the major industries including; automotive, aerospace, marine, construction, agriculture and health science.
    However, several improvements regarding the strength, dimensional stability and the cost of production are required.
    In this study, composite of Kenaf, multi-wall carbon nanotube (MWCNT) and polypropylene (PP) with maleic anhydridegrafted
    polypropylene (MAPP) are examined. The results highlight that increasing MAPP loading, in turn, increases the
    value of the mechanical properties. The composites are produced by blending kenaf/MWCNT/PP using a Sigma blade
    mixer and injection moulding. Injection moulding is a significant operation used to produce plastic products. In the
    study, Kenaf core fibre was mixed with MWCNT and polypropylene, in addition to MAPP. The MAPP is added by applying
    different percentage (1, 2, 3 and 4 wt. %) during the blending process. The main objective of the study was to analyse the
    effects of MAPP concentrations on the mechanical properties of the Kenaf/MWCNT/PP composite. The results of the study
    established that MAPP 3 wt. % concentration with MWCNT 3 wt. % loading and Kenaf 30 wt. % filler provide optimum
    results for the composites. There was approximately, a 21% enhance in tensile strength of Kenaf 30 wt. %/MWCNT, 3 wt.
    %/MAPP, 3 wt. %/PP observed compared to the (without) MAPP composite. The composites with coupling agent stimulate
    better filler dispersion between Kenaf, MWCNT and PP observed using a scanning electron microscope (SEM) and fieldemission
    scanning electron microscope (FESEM).
    Matched MeSH terms: Tensile Strength
  9. Effects of debinding and sintering atmosphere on properties and corrosion resistance of powder injection molded 316 L - stainless steel
    Raza MR, Sherazi I, Muhammad Aslam, Ahmad F, Abu Bakar Sulong, Muhamad Norhamidi, et al.
    Sains Malaysiana, 2017;46:285-293.
    316L stainless steel is a common biomedical material. Currently, biomedical parts are produced through powder injection molding (PIM). Carbon control is the most critical in PIM. Improper debinding can significantly change the properties of the final product. In this work, thermal debinding and sintering were performed in two different furnaces (i.e. laboratory and commercially available furnaces) to study the mechanical properties and corrosion resistance. Debounded samples were sintered in different atmospheres. The samples sintered in inert gas showed enhanced mechanical properties compared with wrought 316L stainless steel and higher corrosion rate than those sintered in the vacuum furnace. The densification and tensile strength of the hydrogen sintered samples increased up to 3% and 51%, respectively, compared with those of the vacuum-sintered samples. However, the samples sintered in inert gas also exhibited reduced ductility and corrosion resistance. This finding is attributed to the presence of residual carbon in debonded samples during debinding.
    Matched MeSH terms: Tensile Strength
  10. Fulltext Properties and Characterization of a PLA-Chitin-Starch Biodegradable Polymer Composite
    Olaiya NG, Surya I, Oke PK, Rizal S, Sadiku ER, Ray SS, et al.
    Polymers (Basel), 2019 Oct 11;11(10).
    PMID: 31614623 DOI: 10.3390/polym11101656
    This paper presents a comparison on the effects of blending chitin and/or starch with poly(lactic acid) (PLA). Three sets of composites (PLA-chitin, PLA-starch and PLA-chitin-starch) with 92%, 94%, 96% and 98% PLA by weight were prepared. The percentage weight (wt.%) amount of the chitin and starch incorporated ranges from 2% to 8%. The mechanical, dynamic mechanical, thermal and microstructural properties were analyzed. The results from the tensile strength, yield strength, Young's modulus, and impact showed that the PLA-chitin-starch blend has the best mechanical properties compared to PLA-chitin and PLA-starch blends. The dynamic mechanical analysis result shows a better damping property for PLA-chitin than PLA-chitin-starch and PLA-starch. On the other hand, the thermal property analysis from thermogravimetry analysis (TGA) shows no significant improvement in a specific order, but the glass transition temperature of the composite increased compared to that of neat PLA. However, the degradation process was found to start with PLA-chitin for all composites, which suggests an improvement in PLA degradation. Significantly, the morphological analysis revealed a uniform mix with an obvious blend network in the three composites. Interestingly, the network was more significant in the PLA-chitin-starch blend, which may be responsible for its significantly enhanced mechanical properties compared with PLA-chitin and PLA-starch samples.
    Matched MeSH terms: Tensile Strength
  11. Fulltext Effects of Modified Metakaolin Using Nano-Silica on the Mechanical Properties and Durability of Concrete
    Shafiq N, Kumar R, Zahid M, Tufail RF
    Materials (Basel), 2019 Jul 17;12(14).
    PMID: 31319615 DOI: 10.3390/ma12142291
    This paper discussed the effects of modified metakaolin (MK) with nano-silica (NS) on the mechanical properties and durability of concrete. In the first phase, trial mixes of concrete were prepared for achieving the desired value of the 28 days compressive strength, and the charge passed in rapid chloride permeability test (RCPT). In the second phase, statistical analysis was performed on the experimental results using the response surface method (RSM). The RSM was applied for optimizing the mix proportions for the required performance by exploiting the relationship between the mix characteristics and the corresponding test results. A blend of 10% MK + 1% NS as part of cement replacement exhibited the highest mechanical properties and durability characteristics of concrete; concrete mix showed that the 28-days compressive strength (CS) was 103 MPa, which was 15% greater than the CS of the control mix without MK or NS. The same mix showed more than 40% higher flexural and split-tensile strength than the control mix; also it resulted in a reduction of 73% in the rapid chloride permeability value. ANOVA technique was used for optimizing the nano-silica and metakaolin content for achieving maximum compressive strength and minimum RCPT value. Statistical analysis using ANOVA technique showed that the maximum compressive strength and lowest RCPT value could be achieved with a blend of 10% MK and 1.55% NS.
    Matched MeSH terms: Tensile Strength
  12. Fulltext Improving Performance of Electrospun Nylon 6,6 Nanofiber Membrane for Produced Water Filtration via Solvent Vapor Treatment
    Abd Halim NS, Wirzal MDH, Bilad MR, Md Nordin NAH, Adi Putra Z, Sambudi NS, et al.
    Polymers (Basel), 2019 Dec 17;11(12).
    PMID: 31861059 DOI: 10.3390/polym11122117
    Electrospun nanofiber membrane (NFM) has a high potential to be applied as a filter for produced water treatment due to its highly porous structure and great permeability. However, it faces fouling issues and has low mechanical properties, which reduces the performance and lifespan of the membrane. NFM has a low integrity and the fine mat easily detaches from the sheet. In this study, nylon 6,6 was selected as the polymer since it offers great hydrophilicity. In order to increase mechanical strength and separation performance of NFM, solvent vapor treatment was implemented where the vapor induces the fusion of fibers. The fabricated nylon 6,6 NFMs were treated with different exposure times of formic acid vapor. Results show that solvent vapor treatment helps to induce the fusion of overlapping fibers. The optimum exposure time for solvent vapor is 5 h to offer full retention of dispersed oil (100% of oil rejection), has 62% higher in tensile strength (1950 MPa) compared to untreated nylon 6,6 NFM (738 MPa), and has the final permeability closest to the untreated nylon 6,6 NFM (733 L/m2.h.bar). It also took more time to get fouled (220 min) compared to untreated NFM (160 min).
    Matched MeSH terms: Tensile Strength
  13. Fulltext Polypropylene/Graphene Nanocomposites: Effects of GNP Loading and Compatibilizers on the Mechanical and Thermal Properties
    Al-Saleh MA, Yussuf AA, Al-Enezi S, Kazemi R, Wahit MU, Al-Shammari T, et al.
    Materials (Basel), 2019 Nov 27;12(23).
    PMID: 31783544 DOI: 10.3390/ma12233924
    In this research work, graphene nanoplatelets (GNP) were selected as alternative reinforcing nanofillers to enhance the properties of polypropylene (PP) using different compatibilizers called polypropylene grafted maleic anhydride (PP-g-MA) and ethylene-octene elastomer grafted maleic anhydride (POE-g-MA). A twin screw extruder was used to compound PP, GNP, and either the PP-g-MA or POE-g-MA compatibilizer. The effect of GNP loading on mechanical and thermal properties of neat PP was investigated. Furthermore, the influence and performance of different compatibilizers on the final properties, such as mechanical and thermal, were discussed and reported. Tensile, flexural, impact, melting temperature, crystallization temperature, and thermal stability were evaluated by using a universal testing system, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). For mechanical properties, it was found that increasing GNP content from 1 wt.% to 5 wt.% increased tensile strength of the neat PP up to 4 MPa. The influence of compatibilizers on the mechanical properties had been discussed and reported. For instance, the addition of PP-g-MA compatibilizer improved tensile strength of neat PP with GNP loading. However, the addition of compatibilizer POE-g-MA slightly decreased the tensile strength of neat PP. A similar trend of behavior was observed for flexural strength. For thermal properties, it was found that both GNP loading and compatibilizers have no significant influence on both crystallization and melting temperature of neat PP. For thermal stability, however, it was found that increasing the GNP loading had a significant influence on improving the thermal behavior of neat PP. Furthermore, the addition of compatibilizers into the PP/GNP nanocomposite had slightly improved the thermal stability of neat PP.
    Matched MeSH terms: Tensile Strength
  14. Fulltext Carbon Nanotubes (CNTs)-Reinforced Magnesium-Based Matrix Composites: A Comprehensive Review
    Abazari S, Shamsipur A, Bakhsheshi-Rad HR, Ismail AF, Sharif S, Razzaghi M, et al.
    Materials (Basel), 2020 Oct 04;13(19).
    PMID: 33020427 DOI: 10.3390/ma13194421
    In recent years considerable attention has been attracted to magnesium because of its light weight, high specific strength, and ease of recycling. Because of the growing demand for lightweight materials in aerospace, medical and automotive industries, magnesium-based metal matrix nanocomposites (MMNCs) reinforced with ceramic nanometer-sized particles, graphene nanoplatelets (GNPs) or carbon nanotubes (CNTs) were developed. CNTs have excellent material characteristics like low density, high tensile strength, high ratio of surface-to-volume, and high thermal conductivity that makes them attractive to use as reinforcements to fabricate high-performance, and high-strength metal-matrix composites (MMCs). Reinforcing magnesium (Mg) using small amounts of CNTs can improve the mechanical and physical properties in the fabricated lightweight and high-performance nanocomposite. Nevertheless, the incorporation of CNTs into a Mg-based matrix faces some challenges, and a uniform distribution is dependent on the parameters of the fabricating process. The characteristics of a CNTs reinforced composite are related to the uniform distribution, weight percent, and length of the CNTs, as well as the interfacial bonding and alignment between CNTs reinforcement and the Mg-based matrix. In this review article, the recent findings in the fabricating methods, characterization of the composite's properties, and application of Mg-based composites reinforced with CNTs are studied. These include the strategies of fabricating CNT-reinforced Mg-based composites, mechanical responses, and corrosion behaviors. The present review aims to investigate and conclude the most relevant studies conducted in the field of Mg/CNTs composites. Strategies to conquer complicated challenges are suggested and potential fields of Mg/CNTs composites as upcoming structural material regarding functional requirements in aerospace, medical and automotive industries are particularly presented.
    Matched MeSH terms: Tensile Strength
  15. New antimicrobial and collagen crosslinking formulated dentin adhesive with improved bond durability
    Daood U, Omar H, Qasim S, Nogueira LP, Pichika MR, Mak KK, et al.
    J Mech Behav Biomed Mater, 2020 10;110:103927.
    PMID: 32957222 DOI: 10.1016/j.jmbbm.2020.103927
    OBJECTIVE: Here we describe a novel formulation, based on quaternary ammonium (QA) and riboflavin (RF), which combines antimicrobial activities and protease inhibitory properties with collagen crosslinking without interference to bonding capabilities, was investigated.

    METHODS: Experimental adhesives modified with different fractions of dioctadecyldimethyl ammonium bromide quaternary ammonium and riboflavin (QARF) were formulated. Dentine specimens were bonded to resincomposites with control or the experimental adhesives to be evaluated for bond strength, interfacial morphology, micro-Raman analysis, nano-CT and nano-leakage expression. In addition, the antibacterial and biocompatibilities of the experimental adhesives were investigated. The endogenous proteases activities and their molecular binding-sites were studied.

    RESULTS: Modifying the experimental adhesives with QARF did not adversely affect micro-tensile bond strength or the degree of conversion along with the demonstration of anti-proteases and antibacterial abilities with acceptable biocompatibilities. In general, all experimental adhesives demonstrated favourable bond strength with increased and improved values in 1% QARF adhesive at 24 h (39.2 ± 3.0 MPa) and following thermocycling (34.8 ± 4.3 MPa).

    SIGNIFICANCE: It is possible to conclude that the use of QARF with defined concentration can maintain bond strength values when an appropriate protocol is used and have contributed in ensuring a significant decrease in microbial growth of biofilms. Incorporation of 1% QARF in the experimental adhesive lead to simultaneous antimicrobial and anti-proteolytic effects with low cytotoxic effects, acceptable bond strength and interfacial morphology.

    Matched MeSH terms: Tensile Strength
  16. Fulltext Pseudo-Ductility, Morphology and Fractography Resulting from the Synergistic Effect of CaCO3 and Bentonite in HDPE Polymer Nano Composite
    Ahmed T, Ya HH, Khan R, Hidayat Syah Lubis AM, Mahadzir S
    Materials (Basel), 2020 Jul 27;13(15).
    PMID: 32726965 DOI: 10.3390/ma13153333
    Polymeric materials such as High density polyethylene(HDPE) are ductile in nature, having very low strength. In order to improve strength by non-treated rigid fillers, polymeric materials become extremely brittle. Therefore, this work focuses on achieving pseudo-ductility (high strength and ductility) by using a combination of rigid filler particles (CaCO3 and bentonite) instead of a single non-treated rigid filler particle. The results of all tensile-tested (D638 type i) samples signify that the microstructural features and surface properties of rigid nano fillers can render the required pseudo-ductility. The maximum value of tensile strength achieved is 120% of the virgin HDPE, and the value of elongation is retained by 100%. Furthermore, the morphological and fractographic analysis revealed that surfactants are not always going to obtain polymer-filler bonding, but the synergistic effect of filler particles can carry out sufficient bonding for stress transfer. Moreover, pseudo-ductility was achieved by a combination of rigid fillers (bentonite and CaCO3) when the content of bentonite dominated as compared to CaCO3. Thus, the achievement of pseudo-ductility by the synergistic effect of rigid particles is the significance of this study. Secondly, this combination of filler particles acted as an alternative for the application of surfactant and compatibilizer so that adverse effect on mechanical properties can be avoided.
    Matched MeSH terms: Tensile Strength
  17. Fulltext Characterization and Performance Evaluation of Cellulose Acetate-Polyurethane Film for Lead II Ion Removal
    Iqhrammullah M, Marlina M, Khalil HPSA, Kurniawan KH, Suyanto H, Hedwig R, et al.
    Polymers (Basel), 2020 Jun 09;12(6).
    PMID: 32526903 DOI: 10.3390/polym12061317
    Global pollution from toxic metal waste has resulted in increased research on toxic metal adsorption. A cellulose acetate-polyurethane (CA-PU) film adsorbent was successfully prepared in this research. The cellulose acetate-polyurethane film adsorbent was prepared with a polycondensation reaction between cellulose acetate and methylene diphenyl diisocyanate. The CA-PU bond formation was confirmed by functional group analysis obtained from Fourier transform infrared (FTIR) spectroscopy. The obtained film was characterized for improved tensile and thermal properties with the addition of methylene diphenyl diisocyanate (MDI). The adsorption ability of the obtained film was evaluated with laser-induced breakdown spectroscopy (LIBS). The best film adsorbent from the LIBS was selected and studied for adsorption isotherm. The FTIR analysis confirmed the formation of the CA-PU bond from the polycondensation between cellulose acetate and the methylene diphenyl diisocyanate. The result showed that the addition of methylene diphenyl diisocyanate (MDI) resulted in the urethane network's growth. The characterization result showed an improvement in the morphology, thermal stability, and tensile strength of the film. The LIBS studies showed improvement in the adsorption of Pb2+ with CA-PU compared with the neat CA. The isotherm studies revealed that Pb2+ adsorption by cellulose acetate-polyurethane film adsorbent was heterogeneously dependent on the Freundlich isotherm model (R2 = 0.97044). Overall, the polycondensation method proposed by this study enhanced the Pb2+ removal, and was comparable to those reported in previous studies.
    Matched MeSH terms: Tensile Strength
  18. Fulltext Mercerization Optimization of Bamboo (Bambusa vulgaris) Fiber-Reinforced Epoxy Composite Structures Using a Box-Behnken Design
    Hassan MZ, Roslan SA, Sapuan SM, Rasid ZA, Mohd Nor AF, Md Daud MY, et al.
    Polymers (Basel), 2020 Jun 17;12(6).
    PMID: 32560539 DOI: 10.3390/polym12061367
    The objective of this research is to optimize the alkaline treatment variables, including sodium hydroxide (NaOH) concentration, soaking, and drying time, that influence the mechanical behavior of bamboo fiber-reinforced epoxy composites. In this study, a Box-Behnken design (BBD) of the response surface methodology (RSM) was employed to design an experiment to investigate the mercerization effect of bamboo fiber-reinforced epoxy composites. The evaluation of predicted tensile strength as a variable parameter of bamboo fiber (Bambusa vulgaris) reinforced epoxy composite structures was determined using analysis of variance (ANOVA) of the quadratic model. In this study, a total of 17 experiment runs were measured and a significant regression for the coefficient between the variables was obtained. Further, the triangular and square core structures made of treated and untreated bamboo fiber-reinforced epoxy composites were tested under compressive loading. It was found that the optimum mercerization condition lies at 5.81 wt.% of the NaOH, after a soaking time of 3.99 h and a drying time of 72 h. This optimum alkaline treatment once again had a great effect on the structures whereby all the treated composite cores with square and triangular structures impressively outperformed the untreated bamboo structures. The treated triangular core of bamboo reinforced composites gave an outstanding performance compared to the treated and untreated square core composite structures for compressive loading and specific energy absorbing capability.
    Matched MeSH terms: Tensile Strength
  19. Fulltext Mechanical Strength, Thermal Conductivity and Electrical Breakdown of Kenaf Core Fiber/Lignin/Polypropylene Biocomposite
    Ahmad Saffian H, Talib MA, Lee SH, Md Tahir P, Lee CH, Ariffin H, et al.
    Polymers (Basel), 2020 Aug 15;12(8).
    PMID: 32824275 DOI: 10.3390/polym12081833
    Mechanical strength, thermal conductivity and electrical breakdown of polypropylene/lignin/kenaf core fiber (PP/L/KCF) composite were studied. PP/L, PP/KCF and PP/L/KCF composites with different fiber and lignin loading was prepared using a compounding process. Pure PP was served as control. The results revealed that tensile and flexural properties of the PP/L/KCF was retained after addition of lignin and kenaf core fibers. Thermal stability of the PP composites improved compared to pure PP polymer. As for thermal conductivity, no significant difference was observed between PP composites and pure PP. However, PP/L/KCF composite has higher thermal diffusivity. All the PP composites produced are good insulating materials that are suitable for building. All PP composites passed withstand voltage test in air and oil state as stipulated in IEC 60641-3 except PP/L in oil state. SEM micrograph showed that better interaction and adhesion between polymer matrix, lignin and kenaf core fibers was observed and reflected on the better tensile strength recorded in PP/L/KCF composite. This study has successfully filled the gap of knowledge on using lignin and kenaf fibers as PP insulator composite materials. Therefore, it can be concluded that PP/Lignin/KCF has high potential as an insulating material.
    Matched MeSH terms: Tensile Strength
  20. Fulltext Effects of Accelerated Weathering on Degradation Behavior of Basalt Fiber Reinforced Polymer Nanocomposites
    Hashim UR, Jumahat A, Jawaid M, Dungani R, Alamery S
    Polymers (Basel), 2020 Nov 06;12(11).
    PMID: 33172162 DOI: 10.3390/polym12112621
    This work aims to give insight on the effect of accelerated weathering, i.e., the combination of ultraviolet (UV) exposure and water spraying, on the visual and mechanical properties of basalt fiber reinforced polymer (BFRP) composites. The solvent exchange method, sonication and high shear milling technique were used to prepare the nanocomposite laminates. Three types of laminates were fabricated, i.e., unmodified BFRP, nanosilica modified BFRP and graphene nanoplatelet (GNP) modified BFRP composites with the total fiber loading of 45 wt.%. Glass fiber reinforced polymer (GFRP) laminate was also prepared for performance comparison purposes between the natural and synthetic fibers. The laminates were exposed to UV with a total weathering condition of 504 h using a Quantum-UV accelerated weathering tester. The weathering condition cycle was set at 8 h 60 °C UV exposure and 4 h 50 °C condensation. The discoloration visual inspection on the tested specimen was observed under the optical microscope. The obtained results showed that the UV exposure and water absorption caused severe discoloration of the laminates due to photo-oxidation reaction. The effect of weathering conditions on tensile and flexural properties of unmodified BFRP composites indicated that the UV exposure and water absorption caused reduction by 12% in tensile strength and by 7% in flexural strength. It is also found that the reduction in tensile and flexural properties of nanomodified BFRP composites was smaller than the unmodified system. It concluded from this work, that the mineral based composites (i.e., BFRP) has high potential for structural applications owing to its better properties than synthetic based composites (i.e., GFRP).
    Matched MeSH terms: Tensile Strength
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