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Fabrication and characterisation of novel chitosan-based polymer inclusion membranes and their application in environmental remediation

Sadiq AC, Olasupo A, Rahim NY, Ngah WSW, Hanafiah MAKM, Suah FBM

Int J Biol Macromol, 2023 Jul 31;244:125400.
PMID: 37330084 DOI: 10.1016/j.ijbiomac.2023.125400

Several water and wastewater technologies have been implored for the removal of dyes during wastewater treatments; however; different types have been reportedly found in surface and groundwater systems. Hence, there is a need to investigate other water treatment technologies for the complete remediation of dyes in aquatic environments. In this study, novel chitosan-based polymer inclusion membranes (PIMs) were synthesized for the removal of malachite green dye (MG) which is a recalcitrant of great concern in water. Two types of PIMs were synthesized in this study, the first PIM (PIMs-A) was composed of chitosan, bis-(2-ethylhexyl) phosphate (B2EHP), and dioctyl phthalate (DOP). While, the second PIMs (PIMs-B) were composed of chitosan, Aliquat 336, and DOP. The physico-thermal stability of the PIMs was investigated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), both PIMs demonstrated good stability with a weak intermolecular force of attraction amongst the various components of the membranes. The effects of the initial concentration of MG, pH of the MG solution, stripping solution, and time were investigated. At optimum conditions, both membranes (PIM-A and B) recorded the highest efficiencies of 96 % and 98 % at pH 4 and initial contaminants concentration of 50 mg/L, respectively. Finally, both PIMs were used for the removal of MG in different environmental samples (river water, seawater, and tap water) with an average removal efficiency of 90 %. Thus, the investigated PIMs can be considered a potential suitable technique for the removal of dyes and other contaminants from aquatic matrices.

Matched MeSH terms: Polymers/chemistry
Fulltext Antifungal effects of eugenol on Candida albicans adherence to denture polymers

Zanul Abidin Z, Mohd Salleh N, Himratul-Aznita WH, Ahmad SF, Lim GS, Raja Mohd N, et al.

PeerJ, 2023;11:e15750.
PMID: 37601266 DOI: 10.7717/peerj.15750

BACKGROUND: The study's objective is to assess the adherence of C. albicans in different types of denture polymers and the effectiveness of eugenol and commercialized denture cleansers in the removal of C. albicans. Three types of denture base polymers (Lucitone® 199 (High-Impact PMMA), Impact® (conventional PMMA) and Eclipse® (UDMA)) and two hard denture reline materials (Kooliner® and Tokuyama® Rebase II Fast) were used in this study.
METHODS: Three hundred samples were prepared (6 × 2 mm disc shape) and divided into five groups of denture polymers (n = 60) and further subjected into five treatment groups (Polident®, Steradent, distilled water, eugenol 5-minutes, and eugenol 10-min). Three samples were extracted from each treatment group for baseline data (n = 12). Baseline data were used to calculate the initial number of C. albicans adherence. A 0.5 ml immersion solution from each specimen was cultured on YPD agar and incubated for 48 h at 37 °C. Visible colonies were counted using a colony counter machine (ROCKER Galaxy 230).
RESULTS: The result showed that the denture base polymer significantly affected the initial adherence (p = 0.007). The removal of C. albicans was also considerably affected by the denture base polymers and denture cleansers (p

Matched MeSH terms: Polymers/pharmacology
Natural Polymer-Based Graphene Oxide Bio-nanocomposite Hydrogel Beads: Superstructures with Advanced Potentials for Drug Delivery

Rehman S, Madni A, Jameel QA, Usman F, Raza MR, Ahmad F, et al.

AAPS PharmSciTech, 2022 Nov 17;23(8):304.
PMID: 36396831 DOI: 10.1208/s12249-022-02456-w

The current study sought to create graphene oxide-based superstructures for gastrointestinal drug delivery. Graphene oxide has a large surface area that can be used to load anti-cancer drugs via non-covalent methods such as surface adsorption and hydrogen bonding. To enhance the bio-applicability of graphene oxide, nano-hybrids were synthesized by encapsulating the graphene oxide into calcium alginate hydrogel beads through the dripping-extrusion technique. These newly developed bio-nanocomposite hybrid hydrogel beads were evaluated in structural analysis, swelling study, drug release parameters, haemolytic assay, and antibacterial activity. Doxorubicin served as a model drug. The drug entrapment efficiency was determined by UV-spectroscopy analysis and was found to be high at ⁓89% in graphene oxide hybrid hydrogel beads. These fabricated hydrogel beads ensure the drug release from a hybrid polymeric matrix in a more controlled and sustained pattern avoiding the problems associated with a non-hybrid polymeric system. The drug release study of 12 h shows about 83% release at pH 6.8. In vitro drug release kinetics proved that drug release was a Fickian mechanism. The cytotoxic effect of graphene oxide hybrid alginate beads was also determined by evaluating the morphology of bacterial cells and red blood cells after incubation. Additionally, it was determined that the sequential encapsulation of graphene oxide in alginate hydrogel beads hides its uneven edges and lessens the graphene oxide's negative impacts. Also, the antibacterial study and biocompatibility of fabricated hydrogel beads made them potential candidates for gastrointestinal delivery.

Matched MeSH terms: Polymers*
Fulltext Optimisation of Epoxide Ring-Opening Reaction for the Synthesis of Bio-Polyol from Palm Oil Derivative Using Response Surface Methodology

Kamairudin N, Hoong SS, Abdullah LC, Ariffin H, Biak DRA

Molecules, 2021 Jan 27;26(3).
PMID: 33513686 DOI: 10.3390/molecules26030648

The development of bio-polyol from vegetable oil and its derivatives is gaining much interest from polyurethane industries and academia. In view of this, the availability of methyl oleate derived from palm oil, which is aimed at biodiesel production, provides an excellent feedstock to produce bio-polyol for polyurethane applications. In this recent study, response surface methodology (RSM) with a combination of central composite rotatable design (CCRD) was used to optimise the reaction parameters in order to obtain a maximised hydroxyl value (OHV). Three reaction parameters were selected, namely the mole ratio of epoxidised methyl oleate (EMO) to glycerol (1:5-1:10), the amount of catalyst loading (0.15-0.55%) and reaction temperature (90-150 °C) on a response variable as the hydroxyl value (OHV). The analysis of variance (ANOVA) indicated that the quadratic model was significant at 98% confidence level with (p-value > 0.0001) with an insignificant lack of fit and the regression coefficient (R2) was 0.9897. The optimum reaction conditions established by the predicted model were: 1:10 mole ratio of EMO to glycerol, 0.18% of catalyst and 120 °C reaction temperature, giving a hydroxyl value (OHV) of 306.190 mg KOH/g for the experimental value and 301.248 mg KOH/g for the predicted value. This result proves that the RSM model is capable of forecasting the relevant response. FTIR analysis was employed to monitor the changes of functional group for each synthesis and the confirmation of this finding was analysed by NMR analysis. The viscosity and average molecular weight (MW) were 513.48 mPa and 491 Da, respectively.

Matched MeSH terms: Polymers/chemistry*
Poly-(ionic liquid) coated with magnetic nanoparticles for micro solid phase extraction of polycyclic aromatic hydrocarbons in food samples

Muhammad Yunus F, Alias Y, Yahya N, Mohamad Zain NN, Raoov M

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2024 May;41(5):495-512.
PMID: 38466777 DOI: 10.1080/19440049.2024.2326426

Poly(methyl methacrylate-vinyl imidazole bromide) (poly-MMA-IL)-grafted magnetic nanoparticles were successfully developed and applied in the micro-magnetic solid phase extraction (μ-MSPE) for 16 types of polycyclic aromatic hydrocarbons (PAHs) from tea, fried food, and grilled food samples via gas chromatography flame ionization detector (GC-FID). One variable at a time (OVAT) and response surface methodology (RSM) were used for efficient optimization. The validation method showed a good coefficient of determination (R2) ranging from 0.9901 to 0.9982 (n = 3) with linearity of 0.2 μg L-1-500 μg L-1. Detection and quantification limits were 0.06 µg L-1-0.32 µg L-1 and 0.18 µg L-1-0.97 µg L-1. Additionally, satisfactory reproducibility was attained with intra-day and inter-day precisions having RSD ranges of 3.6%-11.1%. The spiked recovery value of 16 PAHs in fried food, grilled food and tea samples obtained from the night market in Malaysia ranged from 80%-12%, respectively.

Matched MeSH terms: Polymers/chemistry
Fulltext All-optical graphene oxide humidity sensors

Lim WH, Yap YK, Chong WY, Ahmad H

Sensors (Basel), 2014;14(12):24329-37.
PMID: 25526358 DOI: 10.3390/s141224329

The optical characteristics of graphene oxide (GO) were explored to design and fabricate a GO-based optical humidity sensor. GO film was coated onto a SU8 polymer channel waveguide using the drop-casting technique. The proposed sensor shows a high TE-mode absorption at 1550 nm. Due to the dependence of the dielectric properties of the GO film on water content, this high TE-mode absorption decreases when the ambient relative humidity increases. The proposed sensor shows a rapid response (<1 s) to periodically interrupted humid air flow. The transmission of the proposed sensor shows a linear response of 0.553 dB/% RH in the range of 60% to 100% RH.

Matched MeSH terms: Polymers
A review of polymer nanofibres by electrospinning and their application in oil-water separation for cleaning up marine oil spills

Sarbatly R, Krishnaiah D, Kamin Z

Mar Pollut Bull, 2016 May 15;106(1-2):8-16.
PMID: 27016959 DOI: 10.1016/j.marpolbul.2016.03.037

The growths of oil and gas exploration and production activities have increased environmental problems, such as oil spillage and the resulting pollution. The study of the methods for cleaning up oil spills is a critical issue to protect the environment. Various techniques are available to contain oil spills, but they are typically time consuming, energy inefficient and create secondary pollution. The use of a sorbent, such as a nanofibre sorbent, is a technique for controlling oil spills because of its good physical and oil sorption properties. This review discusses about the application of nanofibre sorbent for oil removal from water and its current developments. With their unique physical and mechanical properties coupled with their very high surface area and small pore sizes, nanofibre sorbents are alternative materials for cleaning up oil spills.

Matched MeSH terms: Polymers
1,2-Dibenzoylhydrazine

Shanmuga Sundara Raj S, Yamin BM, Boshaala AM, Tarafder MT, Crouse KA, Fun HK

Acta Crystallogr C, 2000 Aug;56 (Pt 8):1011-2.
PMID: 10944308

In the crystal structure of the title compound, C(14)H(12)N(2)O(2), the molecule lies about a twofold axis; two carbonyl groups and the H atoms of the N-N bond are in a trans orientation with respect to each other. In the crystal, each molecule is linked to the other and vice versa by intermolecular N-H.O hydrogen bonds between the amide hydrogen and the O atoms of neighbouring molecules to form two ten-membered rings, each of which has the graph-set motif C4R(2)(2)(10). This extends as a polymeric chain along the c axis.

Matched MeSH terms: Polymers
Immobilization of hydrophobic lipase derivatives on to organic polymer beads

Basri M, Ampon K, Yunus WM, Razak CN, Salleh AB

J Chem Technol Biotechnol, 1994 Jan;59(1):37-44.
PMID: 7764496

A simple and effective method of lipase immobilization is described. Lipase from Candida rugosa was first modified with several hydrophobic modifiers before being adsorbed on to organic polymer beads. The soluble hydrophobic lipase derivatives adsorbed more strongly on to the various polymers as compared with the native lipase. The optimal adsorption temperature of the native and modified lipases on all the polymers was 40 degrees C. The optimal pH of adsorption was between 6 and 7. Lipase immobilized in this manner produced high catalytic recoveries which are affected by the type of modifiers, degree of modification and type of supports used. Monomethoxypolyethylene glycol (1900) activated with p-nitrophenyl chloroformate was found to be the best modifier of the enzyme at 95% modification, for adsorption to the polymers. Increasing the degree of modification of the enzyme increased the activity which was immobilized. Generally, both native and hydrophobic lipase derivatives showed higher specific activities when immobilized on polar polymers compared with non-polar polymers.

Matched MeSH terms: Polymers
Fulltext Shear Response of Glass Fibre Reinforced Polymer (GFRP) Built-Up Hollow and Lightweight Concrete Filled Beams: An Experimental and Numerical Study

Kong SY, Wong LS, Paul SC, Miah MJ

Polymers (Basel), 2020 Oct 02;12(10).
PMID: 33023168 DOI: 10.3390/polym12102270

This paper investigated the static behaviour of glass fibre reinforced polymer (GFRP) built-up hollow and concrete filled built-up beams tested under four-point bending with a span-to-depth ratio of 1.67, therefore focusing their shear performance. Two parameters considered for hollow sections were longitudinal web stiffener and strengthening at the web-flange junction. The experimental results indicated that the GFRP hollow beams failed by web crushing at supports; therefore, the longitudinal web stiffener has an insignificant effect on improving the maximum load. Strengthening web-flange junctions using rectangular hollow sections increased the maximum load by 47%. Concrete infill could effectively prevent the web crushing, and it demonstrated the highest load increment of 162%. The concrete filled GFRP composite beam failed by diagonal tension in the lightweight concrete core. The finite element models adopting Hashin damage criteria yielded are in good agreement with the experimental results in terms of maximum load and failure mode. Based on the numerical study, the longitudinal web stiffener could prevent the web buckling of the slender GFRP beam and improved the maximum load by 136%. The maximum load may be further improved by increasing the thickness of the GFRP section and the size of rectangular hollow sections used for strengthening. It was found that the bond-slip at the concrete-GFRP interface affected the shear resistance of concrete-GFRP composite beam.

Matched MeSH terms: Polymers
Fulltext Biodegradable Polymer Composite For Cosmetic Patch

Sarah Amalina Adli, Fathilah Binti Ali, Azlin Suhaida Azmi, Hazleen Anuar, Rosnani Hasham

Biological and Natural Resources Engineering Journal, 2019;2(2):49-64.
MyJurnal

Patches has recently emerged and attracting more attention for its versatility in many areas such as cosmetic, pharmaceutical and medical. Patches can either be used to administer selected drug to skin or deliver some beneficial ingredients for cosmetic purposes. With that, as polymer is used as the matrix for patches, the polymer selected must be non-toxic, have adhesive property and non-irritative to the skin. Currently, synthetic polymer had been used as the matrix. However, as time passes, people are more concern with the environment, therefore biopolymer is chosen over synthetic polymer as they are degradable and also safe to use. Nowadays, as consumers are demanding for a more effective product that is not only good for appearance but also the health of the skin, studies had been done on many kinds of active ingredient that will give the best effect to the skin. Thus in this paper, patches made up of different combinations of polymer and active ingredients, as well as fabrication method currently used to produce patches will be discussed.

Matched MeSH terms: Biopolymers; Polymers
Composite amine mixed matrix membranes for high-pressure CO2-CH4 separation: synthesis, characterization and performance evaluation

Fauzan NAB, Mukhtar H, Nasir R, Mohshim DFB, Arasu N, Man Z, et al.

R Soc Open Sci, 2020 Sep;7(9):200795.
PMID: 33047043 DOI: 10.1098/rsos.200795

The key challenge in the synthesis of composite mixed matrix membrane (MMMs) is the incompatible membrane fabrication using porous support in the dry-wet phase inversion technique. The key objective of this research is to synthesize thin composite ternary (amine) mixed matrix membranes on microporous support by incorporating 10 wt% of carbon molecular sieve (CMS) and 5-15 wt% of diethanolamine (DEA) in polyethersulfone (PES) dope solution for the separation of carbon dioxide (CO2) from methane (CH4) at high-pressure applications. The developed membranes were evaluated for their morphological structure, thermal and mechanical stabilities, functional groups, as well as for CO2-CH4 separation performance at high pressure (10-30 bar). The results showed that the developed membranes have asymmetric structure, and they are mechanically strong at 30 bar. This new class of PES/CMS/DEA composite MMMs exhibited improved gas permeance compared to pure PES composite polymeric membrane. CO2-CH4 perm-selectivity enhanced from 8.15 to 16.04 at 15 wt% of DEA at 30 bar pressure. The performance of amine composite MMMs is theoretically predicted using a modified Maxwell model. The predictions were in good agreement with experimental data after applying the optimized values with AARE % = ∼less than 2% and R2 = 0.99.

Matched MeSH terms: Polymers
Fulltext Development of Laser Drilling Strategy for Thick Carbon Fibre Reinforced Polymer Composites (CFRP)

Ahmad Sobri S, Heinemann R, Whitehead D

Polymers (Basel), 2020 Nov 12;12(11).
PMID: 33198377 DOI: 10.3390/polym12112674

Composites from carbon fibre reinforced polymers (CFRPs) play a significant role in modern manufacturing. They are typically used in aerospace and other industries that require high strength-to-weight ratios. Composite machining, however, remains a challenging job and sometimes is hampered by poor efficiency. Despite considerable research being conducted over the past few years on the machining of composite materials, the material nevertheless suffers from delamination, fibre loss, and imperfect finishing of the fuselage. Laser technology is becoming increasingly popular as an alternative approach to cutting and drilling composites. Experiments have been conducted with a CFRP thickness of 25.4 mm using fibre laser to test the effect of the machining parameters on the primary performance measurements. In this study, different machining criteria are used to assess the fibre laser ability of thick CFRP composites for drilling operation. The experimental findings revealed that a fibre laser is capable of penetrating a thick CFRP to a depth of 22 mm by using a novel drilling procedure.

Matched MeSH terms: Polymers
Fulltext Emerging Two-Dimensional Crystallization of Cucurbit[8]uril Complexes: From Supramolecular Polymers to Nanofibers

Barrio JD, Liu J, Brady RA, Tan CSY, Chiodini S, Ricci M, et al.

J Am Chem Soc, 2019 09 11;141(36):14021-14025.
PMID: 31422657 DOI: 10.1021/jacs.9b07506

The binding of imidazolium salts to cucurbit[8]uril, CB[8], triggers a stepwise self-assembly process with semiflexible polymer chains and crystalline nanostructures as early- and late-stage species, respectively. In such a process, which involves the crystallization of the host-guest complexes, the guest plays a critical role in directing self-assembly toward desirable morphologies. These include platelet-like aggregates and two-dimensional (2D) fibers, which, moreover, exhibit viscoelastic and lyotropic properties. Our observations provide a deeper understanding of the self-assembly of CB[8] complexes, with fundamental implications in the design of functional 2D systems and crystalline materials.

Matched MeSH terms: Polymers
Effects of thermal radiation on mixed convection flow over a permeable vertical shrinking flat plate in an oldroyd-b fluid

Kohilavani Naganthran, Roslinda Nazar, Ioan Pop

Sains Malaysiana, 2018;47:1069-1076.

This study offers the numerical solutions for the problem of mixed convection stagnation-point flow along a permeable
vertical flat plate in an Oldroyd-B fluid. The present investigation considers the effects of thermal radiation and heat
generation/absorption in the fluid flow. The similarity transformation simplifies the complex model and the bvp4c function
generates the numerical solutions according to the variations in the governing parameters. A higher degree of shrinking
hastens flow separations. The dual solutions are visible in the range of buoyancy opposing flow. The results from this study
may be useful for the scientist to understand the behaviour of the dilute polymer solutions in the industrial applications,
for example, the drag reduction in pipe flows.

Matched MeSH terms: Polymers
Antifouling and antibacterial evaluation of ZnO/MWCNT dual nanofiller polyethersulfone mixed matrix membrane

Pang WY, Ahmad AL, Zaulkiflee ND

J Environ Manage, 2019 Nov 01;249:109358.
PMID: 31450197 DOI: 10.1016/j.jenvman.2019.109358

The aim of this study is to evaluate the performance and antifouling properties of polyethersulfone (PES) membrane incorporated with dual nanofiller, zinc oxide (ZnO) and multi-walled carbon nanotube (MWCNT). The synergistic effect of the these nanofillers in PES membrane is studied by blending different ratio of ZnO/MWCNT nanofiller into the PES membrane. The fabricated membranes were characterized in terms of cross-section and surface morphology, surface hydrophilicity, pore size and porosity. The filtration performance of the membranes was tested using 50 mg/L humic acid (HA) solution as model solution. SEM image and gravimetric evaluation reported that the incorporation of both MWCNT and ZnO into the PES membrane improved porosity significantly up to 46.02%. Lower water contact angle of PES membrane incorporated with equal ratio of MWCNT and ZnO (PES 3) revealed that it has neat PES membrane properties and more hydrophilic membrane surface than single filler. PES 3 outperform other membranes with excellent HA permeate flux of 40.00 L/m2.h and rejection of 88.51%. Due to hydrophilic membrane surface, PES 3 membrane demonstrate efficient antifouling properties with lower relative flux reduction (RFR) and higher flux recovery ratio (FRR). PES 3 also showed notable antibacterial properties with less bacterial attached to the membrane compared to neat PES membrane (PES 0).

Matched MeSH terms: Polymers
Fulltext Conceptual design of natural composite grating platform

Ahmad Fuad Ab Ghani, Mohamad Kamarul Anwar Sahar, Muhammad Ridzuan Husyairi Azmi, Nurul Izzati Medon, Muhammad Syazwan Samsuri, Muhammad Syurabil Abdani

Malaysian Journal of Applied Sciences, 2018;1(2):62-70.
MyJurnal

There are several types of grating, such as platform, bridge decks and filters. In design process, there
are several important terms that have to be prioritised; engineering design, strength to weight ratio, cost,
maintainability, reparability etcetera. Advanced materials, such as composite materials offer great
strength to weight ratio and high mechanical properties for grating fabrication. Furthermore the
reparability and maintenance problems could be solved as it is anti corrosion and the long service life
attribute of composite makes it a great design material for replacement of conventional steel or
aluminium. Bio composites, such as bamboo and coir fiber yield advantage in terms of less cost and
abundance availability compared to commercial unidirectional composite materials, such as glass fiber
reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP) which is considerably
expensive yet possess higher mechanical properties. This papers presents a conceptual design of
grating design utilizing bamboo composite as material. Pugh method has been chosen as design criteria
selection matrix in finalizing the design of industrial grating for scaffolding (Pugh, 1991).

Matched MeSH terms: Polymers
Fulltext Sensing and Self-Sensing Actuation Methods for Ionic Polymer-Metal Composite (IPMC): A Review

MohdIsa W, Hunt A, HosseinNia SH

Sensors (Basel), 2019 Sep 14;19(18).
PMID: 31540032 DOI: 10.3390/s19183967

Ionic polymer-metal composites (IPMC) are smart material transducers that bend in response to low-voltage stimuli and generate voltage in response to bending. IPMCs are mechanically compliant, simple in construction, and easy to cut into desired shape. This allows the designing of novel sensing and actuation systems, e.g., for soft and bio-inspired robotics. IPMC sensing can be implemented in multiple ways, resulting in significantly different sensing characteristics. This paper will review the methods and research efforts to use IPMCs as deformation sensors. We will address efforts to model the IPMC sensing phenomenon, and implementation and characteristics of different IPMC sensing methods. Proposed sensing methods are divided into active sensing, passive sensing, and self-sensing actuation (SSA), whereas the active sensing methods measure one of IPMC-generated voltage, charge, or current; passive methods measure variations in IPMC impedances, or use it in capacitive sensor element circuit, and SSA methods implement simultaneous sensing and actuation on the same IPMC sample. Frequency ranges for reliable sensing vary among the methods, and no single method has been demonstrated to be effective for sensing in the full spectrum of IPMC actuation capabilities, i.e., from DC to ∼100 Hz. However, this limitation can be overcome by combining several sensing methods.

Matched MeSH terms: Polymers
Fulltext Utilization of Bracing Arms as Additional Reinforcement in Pultruded Glass Fiber-Reinforced Polymer Composite Cross-Arms: Creep Experimental and Numerical Analyses

Asyraf MRM, Ishak MR, Sapuan SM, Yidris N

Polymers (Basel), 2021 Feb 19;13(4).
PMID: 33669491 DOI: 10.3390/polym13040620

The application of pultruded glass fiber-reinforced polymer composites (PGFRPCs) as a replacement for conventional wooden cross-arms in transmission towers is relatively new. Although numerous studies have conducted creep tests on coupon-scale PGFRPC cross-arms, none had performed creep analyses on full-scale PGFRPC cross-arms under actual working load conditions. Thus, this work proposed to study the influence of an additional bracing system on the creep responses of PGFRPC cross-arms in a 132 kV transmission tower. The creep behaviors and responses of the main members in current and braced PGFRPC cross-arm designs were compared and evaluated in a transmission tower under actual working conditions. These PGFRPC cross-arms were subjected to actual working loads mimicking the actual weight of electrical cables and insulators for a duration of 1000 h. The cross-arms were installed on a custom test rig in an open area to simulate the actual environment of tropical climate conditions. Further creep analysis was performed by using Findley and Burger models on the basis of experimental data to link instantaneous and extended (transient and viscoelastic) creep strains. The addition of braced arms to the structure reduced the total strain of a cross-arm's main member beams and improved elastic and viscous moduli. The addition of bracing arms improved the structural integrity and stiffness of the cross-arm structure. The findings of this study suggested that the use of a bracing system in cross-arm structures could prolong the structures' service life and subsequently reduce maintenance effort and cost for long-term applications in transmission towers.

Matched MeSH terms: Polymers
Fulltext Warpage Optimisation Using Recycled Polycar-bonates (PC) on Front Panel Housing

Tamizi NAMA, Rahim SZA, Abdellah AE, Abdullah MMAB, Nabiałek M, Wysłocki JJ, et al.

Materials (Basel), 2021 Mar 15;14(6).
PMID: 33804036 DOI: 10.3390/ma14061416

Many studies have been done using recycled waste materials to minimise environmental problems. It is a great opportunity to explore mechanical recycling and the use of recycled and virgin blend as a material to produce new products with minimum defects. In this study, appropriate processing parameters were considered to mould the front panel housing part using R0% (virgin), R30% (30% virgin: 70% recycled), R40% (40% virgin: 60% recycled) and R50% (50% virgin: 50% recycled) of Polycarbonate (PC). The manufacturing ability and quality during preliminary stage can be predicted through simulation analysis using Autodesk Moldflow Insight 2012 software. The recommended processing parameters and values of warpage in x and y directions can also be obtained using this software. No value of warpage was obtained from simulation studies for x direction on the front panel housing. Therefore, this study only focused on reducing the warpage in the y direction. Response Surface Methodology (RSM) and Genetic Algorithm (GA) optimisation methods were used to find the optimal processing parameters. As the results, the optimal ratio of recycled PC material was found to be R30%, followed by R40% and R50% materials using RSM and GA methods as compared to the average value of warpage on the moulded part using R0%. The most influential processing parameter that contributed to warpage defect was packing pressure for all materials used in this study.

Matched MeSH terms: Polymers

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