Displaying publications 1 - 20 of 72 in total

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  1. Biodegradable and antithrombogenic chitosan/elastin blended polyurethane electrospun membrane for vascular tissue integration
    Selvaras T, Alshamrani SA, Gopal R, Jaganathan SK, Sivalingam S, Kadiman S, et al.
    J Biomed Mater Res B Appl Biomater, 2023 Jun;111(6):1171-1181.
    PMID: 36625453 DOI: 10.1002/jbm.b.35223
    Current commercialized vascular membranes to treat coronary heart disease (CHD) such as Dacron and expanded polytetrafluoroethylene (ePTFE) have been associated with biodegradable and thrombogenic issues that limit tissue integration. In this study, biodegradable vascular membranes were fabricated in a structure of electrospun nanofibers composed of polyurethane (PU), chitosan (CS) and elastin (0.5%, 1.0%, and 1.5%). The physicochemical properties of the membranes were analyzed, followed by the conduction of several test analyses. The blending of CS and elastin has increased the fiber diameter, pore size and porosity percentage with the appearance of identical chemical groups. The wettability of PU membranes was enhanced up to 39.6%, demonstrating higher degradation following the incorporation of both natural polymers. The PU/CS/elastin electrospun membranes exhibited a controlled release of CS (Higuchi and first-order mechanisms) and elastin (Higuchi and Korsmeyer-Peppas mechanisms). Delayed blood clotting time was observed through both activated partial thromboplastin time (APTT) and partial thromboplastin time (PT) analyses where significantly delay of 26.8% APTT was recorded on the PU membranes blended with CS and elastin, in comparison with the PU membranes, supporting the membrane's antithrombogenic properties. Besides, these membranes produced a minimum of 2.6 ± 0.1 low hemolytic percentage, projecting its hemocompatibility to be used as vascular membrane.
    Matched MeSH terms: Polyurethanes/chemistry
  2. Development of thermal insulation sandwich panels containing end-of-life vehicle (ELV) headlamp and seat waste
    Wong YC, Mahyuddin N, Aminuddin AMR
    Waste Manag, 2020 Dec;118:402-415.
    PMID: 32947219 DOI: 10.1016/j.wasman.2020.08.036
    Recycling automotive waste has increasingly become an alternative solution towards producing sustainable materials given the rising issue of raw material shortages and waste management challenges at global level. The improper end-of-life vehicle (ELV) waste management poses detrimental impacts on the environment. This paper proposes a novel method to develop thermal insulation sandwich panels using ELV waste, motivated by the critical needs of creating high-performance thermal insulation for buildings. Six sandwich panels (P1-P6) of different weight and ratio of shredded ELV particles were manufactured. The sandwich panels structure was made of three layers: a core, and a glass face sheet bonded to each side. The core structure composed of Polycarbonate (PC) from headlamp lenses and polyurethane (PU) from seat, bonded using resin casting approach. Thermal conductivity of the samples was measured using guarded hot-plate apparatus. Results corroborated that thermal conductivity of ELV-based sandwich panels reduced remarkably compared to panel without ELVs, recorded at 15.51% reduction. Composition gives the best thermal performance was made of mixed ELV core materials of ratio 50%PC:50%PU, it has a thermal conductivity value of 0.1776 W/mK. The transparency data were obtained using Haze-gard plus haze meter. The best luminous transmittance value was exhibited by P2 (100% PC), 67.47%. The best clarity value and haze value were shown by P6 (25% PC: 75% PU), 55.13% and 52.6% respectively. ELV waste can be recycled to develop useful sustainable thermal insulation to improve thermal and optical transparency performance of buildings as a substitute for conventional materials which have a relevance for future façade concepts.
    Matched MeSH terms: Polyurethanes
  3. Bio-based Poly(hydroxy urethane)s: Synthesis and Pre/Post-Functionalization
    Mhd Haniffa MAC, Munawar K, Ching YC, Illias HA, Chuah CH
    Chem Asian J, 2021 Jun 01;16(11):1281-1297.
    PMID: 33871151 DOI: 10.1002/asia.202100226
    New and emerging demand for polyurethane (PU) continues to rise over the years. The harmful isocyanate binding agents and their integrated PU products are at the height of environmental concerns, in particular PU (macro and micro) pollution and their degradation problems. Non-isocyanate poly(hydroxy urethane)s (NIPUs) are sustainable and green alternatives to conventional PUs. Since the introduction of NIPU in 1957, the market value of NIPU and its hybridized materials has increased exponentially in 2019 and is expected to continue to rise in the coming years. The secondary hydroxyl groups of these NIPU's urethane moiety have revolutionized them by allowing for adequate pre/post functionalization. This minireview highlights different strategies and advances in pre/post-functionalization used in biobased NIPU. We have performed a comprehensive evaluation of the development of new ideas in this field to achieve more efficient synthetic biobased hybridized NIPU processes through selective and kinetic understanding.
    Matched MeSH terms: Polyurethanes/chemical synthesis*; Polyurethanes/chemistry
  4. Fulltext Exploiting the oxygen inhibitory effect on UV curing in microfabrication: a modified lithography technique
    Alvankarian J, Majlis BY
    PLoS One, 2015;10(3):e0119658.
    PMID: 25747514 DOI: 10.1371/journal.pone.0119658
    Rapid prototyping (RP) of microfluidic channels in liquid photopolymers using standard lithography (SL) involves multiple deposition steps and curing by ultraviolet (UV) light for the construction of a microstructure layer. In this work, the conflicting effect of oxygen diffusion and UV curing of liquid polyurethane methacrylate (PUMA) is investigated in microfabrication and utilized to reduce the deposition steps and to obtain a monolithic product. The conventional fabrication process is altered to control for the best use of the oxygen presence in polymerization. A novel and modified lithography technique is introduced in which a single step of PUMA coating and two steps of UV exposure are used to create a microchannel. The first exposure is maskless and incorporates oxygen diffusion into PUMA for inhibition of the polymerization of a thin layer from the top surface while the UV rays penetrate the photopolymer. The second exposure is for transferring the patterns of the microfluidic channels from the contact photomask onto the uncured material. The UV curing of PUMA as the main substrate in the presence of oxygen is characterized analytically and experimentally. A few typical elastomeric microstructures are manufactured. It is demonstrated that the obtained heights of the fabricated structures in PUMA are associated with the oxygen concentration and the UV dose. The proposed technique is promising for the RP of molds and microfluidic channels in terms of shorter processing time, fewer fabrication steps and creation of microstructure layers with higher integrity.
    Matched MeSH terms: Polyurethanes/chemistry*
  5. Recent advances in tissue engineering scaffolds based on polyurethane and modified polyurethane
    Naureen B, Haseeb ASMA, Basirun WJ, Muhamad F
    Mater Sci Eng C Mater Biol Appl, 2021 Jan;118:111228.
    PMID: 33254956 DOI: 10.1016/j.msec.2020.111228
    Organ repair, regeneration, and transplantation are constantly in demand due to various acute, chronic, congenital, and infectious diseases. Apart from traditional remedies, tissue engineering (TE) is among the most effective methods for the repair of damaged tissues via merging the cells, growth factors, and scaffolds. With regards to TE scaffold fabrication technology, polyurethane (PU), a high-performance medical grade synthetic polymer and bioactive material has gained significant attention. PU possesses exclusive biocompatibility, biodegradability, and modifiable chemical, mechanical and thermal properties, owing to its unique structure-properties relationship. During the past few decades, PU TE scaffold bioactive properties have been incorporated or enhanced with biodegradable, electroactive, surface-functionalised, ayurvedic products, ceramics, glass, growth factors, metals, and natural polymers, resulting in the formation of modified polyurethanes (MPUs). This review focuses on the recent advances of PU/MPU scaffolds, especially on the biomedical applications in soft and hard tissue engineering and regenerative medicine. The scientific issues with regards to the PU/MPU scaffolds, such as biodegradation, electroactivity, surface functionalisation, and incorporation of active moieties are also highlighted along with some suggestions for future work.
    Matched MeSH terms: Polyurethanes*
  6. Compression and tension behavior of the prosthetic foam materials polyurethane, EVA, Pelite™ and a combination of polyurethane and EVA: a preliminary study
    Lutfi SNN, Abd Razak NA, Ali S, Gholizadeh H
    Biomed Tech (Berl), 2021 Jun 25;66(3):317-322.
    PMID: 34062632 DOI: 10.1515/bmt-2019-0110
    Materials with low-strength and low-impedance properties, such as elastomers and polymeric foams are major contributors to prosthetic liner design. Polyethylene-Light (Pelite™) is a foam liner that is the most frequently used in prosthetics but it does not cater to all amputees' limb and skin conditions. The study aims to investigate the newly modified Foam Liner, a combination of two different types of foams (EVA + PU + EVA) as the newly modified Foam Liner in terms of compressive and tensile properties in comparison to Pelite™, polyurethane (PU) foam, and ethylene-vinyl acetate (EVA) foam. Universal testing machine (AGS-X, Shimadzu, Kyoto, Japan) has been used to measure the tensile and compressive stress. Pelite™ had the highest compressive stress at 566.63 kPa and tensile stress at 1145 kPa. Foam Liner fell between EVA and Pelite™ with 551.83 kPa at compression and 715.40 kPa at tension. PU foam had the lowest compressive stress at 2.80 kPa and tensile stress at 33.93 kPa. Foam Liner has intermediate compressive elasticity but has high tensile elasticity compared to EVA and Pelite™. Pelite™ remains the highest in compressive and tensile stiffness. Although it is good for amputees with bony prominence, constant pressure might result in skin breakdown or ulcer. Foam Liner would be the best for amputees with soft tissues on the residual limbs to accommodate movement.
    Matched MeSH terms: Polyurethanes*
  7. 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: Polyurethanes/chemistry
  8. Fulltext Effects of sintering time on the physical and compositional properties of porous biphasic calcium phosphate foam
    Cik Rohaida, C.H., Idris, B., Rusnah, M., Mohd Reusmaazran, Y., Narimah, A.B.
    Journal of Nuclear and Related Technologies, 2009;2009(1):206-216.
    MyJurnal
    Phase composition of calcium phosphate ceramic is a characteristic directly related to the biological response of implants due to the differences in mechanical and biochemical properties of these compounds. The biodegradation rate of biphasic calcium phosphate (BCP) can be controlled by altering the HA to β-TCP ratios. In this study the crystalline phase evolution of BCP synthesized via precipitation from aqueous solution of (NH4)2PO4 titrated into heated solution of Ca (NO3)2 was evaluated. The resulting powder was fabricated into porous scaffold using polyurethane foam method. Bulk powders were sintered from 700 - 1400°C to determine the most significant sintering temperature to obtain a stable and well crystallize BCP phases. The porous scaffolds were then sintered at selected temperature and the effects of various sintering times from 5,7,9,11,13 and 15 h were investigated. Bulk powders were characterized by dilatometer, IR analysis and XRD and porous scaffolds were analyzed by XRD and SEMEdx. RIR method was performed to show that the HA to β-TCP ratios were increased with increasing of sintering time and reached the maximum HA value at 11h. It is found that, the possibilities to manipulate the HA to β-TCP ratios in BCP porous scaffold by just controlling the sintering time of the scaffold without controlling the starting powder characteristics.
    Matched MeSH terms: Polyurethanes
  9. Effect of phosphite loading on the mechanical and fire properties of palm-based polyurethane
    Khairiah Badri, Amamer Musbah Redwan
    Sains Malaysiana, 2010;39.
    Fire-retarding polyurethane (PU) composite was produced by adding 2,4-ditert-butylphenyl phosphite (FR) to palm-based monoester resin with loading percentage of 0, 2, 4, and 6 wt%. The Shore D hardness index increased marginally with increasing FR content. However, the impact and flexural strengths decreased with increasing FR loading attributed to the weak interfacial bonding between FR and PU matrix. The fire test indicated lowering of burning rate (from 5.30 mm.s-1 to 2.80 mm.s-1) as the loading percentage of FR increased. The combustion enthalpy of the composites also decreased with higher loading percentage of FR.
    Matched MeSH terms: Polyurethanes
  10. Fulltext Polyurethane Elastomer Layered Nanocomposite Material for Sports Grounds and the Preparation Method Thereof
    Ren C, Su Z, Su Y, Wang L
    Biomed Res Int, 2022;2022:5152911.
    PMID: 36093408 DOI: 10.1155/2022/5152911
    Polyurethane, as a rubber material, can relieve the load on the ground and provide seismic design for the venue, which is of great significance for sports venues. In order to improve the seismic resistance and abrasion resistance of materials for sports fields and reduce accidents in sports, this article has carried out research on the polyurethane elastomer layered nanocomposites for sports fields and their preparation. Today's world is a challenging era of science and technology. The fields of biotechnology, information, medicine, energy, environment, and national defense and security are closely related to the development of high tech, and the requirements for materials are becoming increasingly diversified. Polymer nanocomposite coating has the dual characteristics of organic and inorganic components. It not only retains the advantages of a polymer but also endows it with versatility. It meets the current application needs. It is a hot spot in today's research. Among them, there are two major problems in the composite process of nanomaterials and polymers: dispersion and compatibility. How to improve the dispersion of nanoparticles and enhance the compatibility between nanoparticles and polymers is an urgent problem to be solved. In the method part, this article introduces a small amount of polyurethane and polyurethane elastomers formed after polyurethane modification and introduces layered compounds and nanocomposites and introduces several models involved in nanomaterials in terms of algorithms. In the analysis part, this paper conducts a comprehensive analysis of the hard segment mass fraction, mechanical properties, thermal decomposition behavior, degradation mechanism, and dynamic mechanical properties. With the increase of GO content, the tensile strength increases significantly and the elongation at break becomes smaller and smaller. When the GO content increases from 0% to 2%, the tensile properties of the WPU film increase from 2.6 MPa to 7.9 MPa and the fracture of the elongation decreased from 201.7% to 62.8%. This shows that the increase in GO content will make the composite material harder and brittle. It can be seen from the experimental results that the preparation of the polyurethane elastomer layered nanocomposite material designed in this paper has a good application effect on sports venues.
    Matched MeSH terms: Polyurethanes
  11. Comparison of linear-linear and hyperbranched-linear dental composite
    Darmawati MY, Ismarul N, Fuad Y, Fazan F
    Med J Malaysia, 2004 May;59 Suppl B:27-8.
    PMID: 15468802
    Linear polymers have been commonly used as dental composite. However the aim of this work is to use hyperbranched polymer in an attempt to produce dental composite. The reason is because the dendritic molecules have shown low viscosity at higher molecular weight compared to the linear counterparts. Therefore, this work attempts to substitute the linear polymer with as much of hyperbranched polymer in the dental composite that would pass the required ISO 4049:1998(E) "Dentistry - Resin-based filling material". Several formulations of dental composites were used, i.e. combinations of linear-linear and linear-hyperbranched polymers for comparison. Following this, physical and mechanical characterisation were conducted based on the ISO standards such as water sorption and water solubility. Other characterisation such as polymerisation shrinkage and Vickers hardness were also evaluated. It was found that different types of resins give different physical and mechanical properties. The maximum achievable hyperbranched polymer, which passes the required ISO standard, that can be incorporated in the linear polymer to form dental composite is 43% wt.
    Matched MeSH terms: Polyurethanes/standards*
  12. Bio-based polyurethane reinforced with cellulose nanofibers: a comprehensive investigation on the effect of interface
    Benhamou K, Kaddami H, Magnin A, Dufresne A, Ahmad A
    Carbohydr Polym, 2015 May 20;122:202-11.
    PMID: 25817660 DOI: 10.1016/j.carbpol.2014.12.081
    Novel bio-based polyurethane (PU) nanocomposites composed of cellulose nanofiller extracted from the rachis of date palm tree and polycaprolactone (PCL) diol based PU were prepared by casting/evaporation. Two types of nanofiber were used: cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs). The mechanical and thermal properties of the nanocomposite films were studied by DMA, DSC, and tensile tests and the morphology was investigated by SEM. Bionanocomposites presented good mechanical properties in comparison to neat PU. While comparing both nanofillers, the improvement in mechanical and thermal properties was more pronounced for the nanocomposites based on CNF which could be explained, not only by the higher aspect ratio of CNF, but also by their better dispersion in the PU matrix. Calculation of the solubility parameters of the nanofiller surface polymers and of the PU segments portend a better interfacial adhesion for CNF based nanocomposites compared to CNC.
    Matched MeSH terms: Polyurethanes/chemistry*
  13. Venous leg ulcers managed using polyurethane foam with a micropore dressing: two case reports
    Nair HKR
    J Wound Care, 2018 Sep 01;27(Sup9a):S37-S40.
    PMID: 30207848 DOI: 10.12968/jowc.2018.27.Sup9a.S37
    BACKGROUND: Cases of venous leg ulcers (VLU) are expected to rise due to the rapidly ageing population in Malaysia. Central to the management of these wounds is compression therapy together with an appropriate wound dressing. Pain and discomfort during dressing changes are common in these patients. Polyurethane foam dressings with SMARTPORE technology (micropore dressing; Mundipharma) facilitate vertical absorption of exudate to reduce risks of wound and periwound area maceration. They support easy dressing removal with less pain and trauma to the wound bed. Thus, the micropore dressing was chosen as a viable treatment option in these cases.

    CASES: Case 1, a 74-year-old diabetic female was treated for bilateral VLUs with micropore dressing for several months, which she noted to be painless and convenient. Case 2, a 49-year-old housewife with a solitary VLU was treated with micropore dressing, leading to good treatment results and high satisfaction.

    CONCLUSION: VLUs managed by the micropore dressing resulted in reduced pain and ease of use during dressing changes, as well as noticeable reduction in wound and periwound area maceration. The use of this type of dressing in these cases shows encouraging results and provides a desirable management option. More robust clinical studies are necessary to establish this.

    Matched MeSH terms: Polyurethanes*
  14. Fulltext Surface, thermal and hemocompatible properties of novel single stage electrospun nanocomposites comprising polyurethane blended with bio oilTM
    Ayyar M, Mani MP, Jaganathan SK, Rathinasamy R, Khudzari AZ, Krishnasamy NP
    An Acad Bras Cienc, 2017;89(3 Suppl):2411-2422.
    PMID: 29091109 DOI: 10.1590/0001-3765201720170230
    In this work, the physicochemical and blood compatibility properties of prepared PU/Bio oil nanocomposites were investigated. Scanning electron microscope (SEM) studies revealed the reduction of mean fiber diameter (709 ± 211 nm) compared to the pristine PU (969 nm ± 217 nm). Fourier transform infrared spectroscopy (FTIR) analysis exposed the characteristic peaks of pristine PU. Composite peak intensities were decreased insinuating the interaction of the bio oilTM with the PU. Contact angle analysis portrayed the hydrophobic nature of the fabricated patch compared to pristine PU. Thermal gravimetric analysis (TGA) depicted the better thermal stability of the novel nanocomposite patch and its different thermal behavior in contrast with the pristine PU. Atomic force microscopy (AFM) analysis revealed the increase in the surface roughness of the composite patch. Activated partial thromboplastin time (APTT) and prothrombin time (PT) signified the novel nanocomposite patch ability in reducing the thrombogenicity and promoting the anticoagulant nature. Finally the hemolytic percentage of the fabricated composite was in the acceptable range revealing its safety and compatibility with the red blood cells. To reinstate, the fabricated patch renders promising physicochemical and blood compatible nature making it a new putative candidate for wound healing application.
    Matched MeSH terms: Polyurethanes/chemistry*
  15. Alternative solid carbon source from dried attached-growth biomass for nitrogen removal enhancement in intermittently aerated moving bed sequencing batch reactor
    Lim JW, Lim PE, Seng CE, Adnan R
    Environ Sci Pollut Res Int, 2014 Jan;21(1):485-94.
    PMID: 23807562 DOI: 10.1007/s11356-013-1933-1
    The feasibility of using dried attached-growth biomass from the polyurethane (PU) foam cubes as a solid carbon source to enhance the denitrification process in the intermittently aerated moving bed sequencing batch reactor (IA-MBSBR) during the treatment of low COD/N containing wastewater was investigated. By packing the IA-MBSBR with 8% (v/v) of 8-mL PU foam cubes saturated with dried attached-growth biomass, total nitrogen removal efficiency of 80% could be achieved for 10 consecutive cycles of operation when the intermittent aeration strategy of consecutive 1 h of aeration followed by 2 h of non-aeration period during the REACT period of the IA-MBSBR was adopted. Negligible release of ammonium nitrogen (NH4(+)-N) and slow-release of COD from the dried biomass would ensure that the use of this solid carbon source would not further burden the treatment system. The slow-releasing COD was found to have no effect in promoting the assimilation process and would also allow the carbon source to be used for many cycles of operation. The 'carbon-spent' PU foam cubes could be reused by merely drying at 60 °C at the end of the operational mode. Thus, the dried attached-growth biomass formed on the PU foam cubes could be exploited as an alternative solid carbon source for the enhancement of denitrification process in the IA-MBSBR.
    Matched MeSH terms: Polyurethanes/chemistry
  16. Fulltext Evaluation of the Compatibility of Organosolv Lignin-Graphene Nanoplatelets with Photo-Curable Polyurethane in Stereolithography 3D Printing
    Ibrahim F, Mohan D, Sajab MS, Bakarudin SB, Kaco H
    Polymers (Basel), 2019 Sep 23;11(10).
    PMID: 31547544 DOI: 10.3390/polym11101544
    In this study, lignin has been extracted from oil palm empty fruit bunch (EFB) fibers via an organosolv process. The organosolv lignin obtained was defined by the presence of hydroxyl-containing molecules, such as guaiacyl and syringyl, and by the presence of phenolic molecules in lignin. Subsequently, the extracted organosolv lignin and graphene nanoplatelets (GNP) were utilized as filler and reinforcement in photo-curable polyurethane (PU), which is used in stereolithography 3D printing. The compatibility as well as the characteristic and structural changes of the composite were identified through the mechanical properties of the 3D-printed composites. Furthermore, the tensile strength of the composited lignin and graphene shows significant improvement as high as 27%. The hardness of the photo-curable PU composites measured by nanoindentation exhibited an enormous improvement for 0.6% of lignin-graphene at 92.49 MPa with 238% increment when compared with unmodified PU.
    Matched MeSH terms: Polyurethanes
  17. Fulltext Green Flexible Polyurethane Foam as a Potent Support for Fe-Si Adsorbent
    Ahmad A, Jamil SNAM, Shean Yaw Choong T, Abdullah AH, Mastuli MS, Othman N, et al.
    Polymers (Basel), 2019 Dec 04;11(12).
    PMID: 31817283 DOI: 10.3390/polym11122011
    This paper describes the preparation, characterisation, and potential application of flexible palm oil-based polyurethane foam (PUF) as a support for iron-silica (Fe-Si) adsorbent. Fe-Si/polyurethane composite (Fe-Si/PUC) was prepared by impregnating Fe-Si adsorbent onto the surface of PUF by using a novel immersion-drying method. Morphological analysis of Fe-Si/PUC proved that Fe-Si was successfully impregnated onto the surface of PUF. Compression test and thermogravimetric analysis were carried out to determine the flexibility and thermal stability of Fe-Si/PUC, respectively. The Fe-Si/PUC removed 90.0% of 10 ppm methylene blue (MB) from aqueous solution in 60 min. The reusability study showed that Fe-Si/PUC removed 55.9% of MB on the seventh cycle. Hence, the synthesis of Fe-Si/PUC opens up a new path of implementing palm oil-based PUF to assist in the recovery of an adsorbent for environmental clean-up. The mechanism of physical interaction during the impregnation of Fe-Si adsorbent onto PUF was proposed in this paper.
    Matched MeSH terms: Polyurethanes
  18. Loading effect of aluminum hydroxide onto them mechanical, thermal conductivity, acoustical and burning properties of the palm-based polyurethane composites
    Nor Rabbi’atul ‘Adawiyah Norzali, Khairiah Badri, Mohd Zaki Nuawi
    Sains Malaysiana, 2011;40:1179-1186.
    Effects of aluminium hydroxide (ATH) addition on the properties of palm-based polyurethane composites were investigated. The hybrid composites were prepared by mixing 10 wt% of oil palm empty fruit bunch fiber (EFB) with ATH at varying amount of 2, 4 and 6 wt% of the overall mass of the resin. The compression stress and modulus gave the highest values of 575 and 2301 kPa, respectively at 2 wt% loading of ATH. The compression stress and modulus decreased drastically at 4 wt% (431 kPa and 1659 kPa, respectively) and further decreased at 6 wt% ATH (339 and 1468 kPa, respectively). However, the burning rate is inversely proportional to the loading percentage where the highest burning rate was observed at 2 wt% ATH. Sound absorption analysis indicated a large absorption coefficient at high frequency (4000 Hz) for all samples. The highest absorption coefficient was obtained from PU-EFB/ATH with 4 wt% ATH.
    Matched MeSH terms: Polyurethanes
  19. Evaluating the toxicity of polyurethane during marine clay stabilisation
    Saleh S, Ahmad K, Mohd Yunus NZ, Hezmi MA
    Environ Sci Pollut Res Int, 2020 Jun;27(17):21252-21259.
    PMID: 32266626 DOI: 10.1007/s11356-020-08549-y
    In civil engineering, many geotechnical and forensic projects employ polyurethane (PU) for ground improvement, and the results have shown to be effective in terms of time and cost savings. However, similar to many other chemical stabilisers, the use of PU for soil stabilisation may have environmental repercussions. Therefore, this paper utilised a toxicity characteristic leaching procedure (TCLP) to investigate the potential for ground contamination resulting from the application of PU for the stabilisation of marine clay. Furthermore, the hazardousness of PU during the stabilisation of marine clay was investigated by testing its reactivity, ignitability, corrosivity and physical properties. The results reveal that the quantity of heavy metals present in PU is far below the regulatory limits. The results further confirm that PU is odourless and non-corrosive and that it is non-cyanide and non-sulphide-bearing. However, PU is capable of igniting. Overall, the potential application of PU for ground improvement is promising due to its environmental friendliness.
    Matched MeSH terms: Polyurethanes
  20. Structure-property studies of thermoplastic and thermosetting polyurethanes using palm and soya oils-based polyols
    Mohammed IA, Al-Mulla EA, Kadar NK, Ibrahim M
    J Oleo Sci, 2013;62(12):1059-72.
    PMID: 24292358
    Palm and soya oils were converted to monoglycerides via transesterification of triglycerides with glycerol by one step process to produce renewable polyols. Thermoplastic polyurethanes (TPPUs) were prepared from the reaction of the monoglycerides which act as polyol with 4,4'-methylenediphenyldiisocyanate (MDI) whereas, thermosetting polyurethanes (TSPUs) were prepared from the reaction of glycerol, MDI and monoglycerides in one pot. Characterization of the polyurethanes was carried out by FT-IR, (1)H NMR, and iodine value and sol-gel fraction. The TSPUs showed good thermal properties compared to TPPUs as well as TSPUs exhibits good properties in pencil hardness and adhesion, however poorer in flexural and impact strength compared to TPPUs. The higher percentage of cross linked fraction, the higher degree of cross linking occurred, which is due to the higher number of double bond presents in the TSPUs. These were reflected in iodine value test as the highest iodine value of the soya-based thermosetting polyurethanes confirmed the highest degree of cross linking. Polyurethanes based on soya oil showed better properties compared to palm oil. This study is a breakthrough development of polyurethane resins using palm and soya oils as one of the raw materials.
    Matched MeSH terms: Polyurethanes/chemical synthesis*; Polyurethanes/chemistry
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