Displaying publications 81 - 100 of 173 in total

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  1. Recent advances in thermal properties of hybrid cellulosic fiber reinforced polymer composites
    Krishnasamy S, Thiagamani SMK, Muthu Kumar C, Nagarajan R, R M S, Siengchin S, et al.
    Int J Biol Macromol, 2019 Dec 01;141:1-13.
    PMID: 31472211 DOI: 10.1016/j.ijbiomac.2019.08.231
    Bio-composites are easy to manufacture and environmentally friendly, could reduce the overall cost and provide lightweight due to the low density of the natural fibers. In a bid to compete with the synthetic fiber reinforced composites, a single natural fiber composite may not be a good choice to obtain optimal properties. Hence, hybrid composites are produced by adding two or more natural fibers together to obtain improved properties, such as mechanical, physical, thermal, water absorption, acoustic and dynamic, among others. Regarding thermal stability, the composites showed a significant change by varying the individual fiber compositions, fiber surface treatments, addition of fillers and coupling agents. The glass transition temperature and melting point obtained from the thermomechanical analysis and differential scanning calorimetry are not the same values for several hybrid composites, since the volume variation was not always parallel with the enthalpy change. However, the difference between the temperature calculated from the thermomechanical analysis and differential scanning calorimetry was lower. Significantly, this critical reviewed study has a potential of guiding all composite designers, manufacturers and users on right selection of composite materials for thermal applications, such as engine components (covers), heat shields and brake ducts, among others.
    Matched MeSH terms: Cellulose/chemistry*
  2. Preparation of palm (Elaeis oleifera) pressed fibre cellulose nanocrystals via cation exchange resin: characterisation and evaluation as Pickering emulsifier
    Soo YT, Ng SW, Tang TK, Ab Karim NA, Phuah ET, Lee YY
    J Sci Food Agric, 2021 Aug 15;101(10):4161-4172.
    PMID: 33428211 DOI: 10.1002/jsfa.11054
    BACKGROUND: Palm pressed fibre (PPF) is a cellulose-rich biomass residue produced during palm oil extraction. Its high cellulose content allows the isolation of cellulose nanocrystal (CNC). CNC has attracted scientific interest due to its biodegradability, biocompatibility and low cost. The present study isolated CNC from PPF using a cation exchange resin, which is an environmentally friendly and less harsh hydrolysis method than conventional mineral acid hydrolysis. Isolated CNC was used to stabilise an oil-in-water emulsion and the emulsion stability was evaluated in terms of droplet size, morphology and physical stability.

    RESULTS: PPF was subjected to alkali and bleach treatment prior to hydrolysis, which successfully removed 54% and 75% of non-cellulosic components (hemicellulose and lignin, respectively). Hydrolysis conditions of 5 h, 15:1 (w/w) resin-to-pulp ratio and 50 °C produced CNC particles of 50-100 nm in length. CNC had a crystallinity index of 42% and appeared rod-like morphologically. CNC-stabilised emulsion had better stability when used in combination with soy lecithin (SL), a well-established, commonly used food stabiliser. Emulsion stabilised by the binary mixture of CNC and SL had droplet size, morphology and physical stability comparable to those of emulsion stabilised using SL.

    CONCLUSIONS: CNC was successfully isolated from PPF through a cation exchange resin. This offers an alternative usage for the underutilised PPF to be converted into value-added products. Isolated CNC was also found to have promising potential in the stabilisation of Pickering emulsions. These results provide useful information indicating CNC as a natural and sustainable stabiliser for food, cosmeceutical and pharmaceutical applications. © 2021 Society of Chemical Industry.

    Matched MeSH terms: Cellulose/chemistry*
  3. Solid acid catalysts pretreatment and enzymatic hydrolysis of macroalgae cellulosic residue for the production of bioethanol
    Tan IS, Lee KT
    Carbohydr Polym, 2015 Jun 25;124:311-21.
    PMID: 25839825 DOI: 10.1016/j.carbpol.2015.02.046
    The aim of this study is to investigate the technical feasibility of converting macroalgae cellulosic residue (MCR) into bioethanol. An attempt was made to present a novel, environmental friendly and economical pretreatment process that enhances enzymatic conversion of MCR to sugars using Dowex (TM) Dr-G8 as catalyst. The optimum yield of glucose reached 99.8% under the optimal condition for solid acid pretreatment (10%, w/v biomass loading, 4%, w/v catalyst loading, 30min, 120°C) followed by enzymatic hydrolysis (45FPU/g of cellulase, 52CBU/g of β-glucosidase, 50°C, pH 4.8, 30h). The yield of sugar obtained was found more superior than conventional pretreatment process using H2SO4 and NaOH. Biomass loading for the subsequent simultaneous saccharification and fermentation (SSF) of the pretreated MCR was then optimized, giving an optimum bioethanol yield of 81.5%. The catalyst was separated and reused for six times, with only a slight drop in glucose yield.
    Matched MeSH terms: Cellulose/chemistry
  4. Fulltext Review of Functional Aspects of Nanocellulose-Based Pickering Emulsifier for Non-Toxic Application and Its Colloid Stabilization Mechanism
    Teo SH, Chee CY, Fahmi MZ, Wibawa Sakti SC, Lee HV
    Molecules, 2022 Oct 23;27(21).
    PMID: 36363998 DOI: 10.3390/molecules27217170
    In the past few years, the research on particle-stabilized emulsion (Pickering emulsion) has mainly focused on the usage of inorganic particles with well-defined shapes, narrow size distributions, and chemical tunability of the surfaces such as silica, alumina, and clay. However, the presence of incompatibility of some inorganic particles that are non-safe to humans and the ecosystem and their poor sustainability has led to a shift towards the development of materials of biological origin. For this reason, nano-dimensional cellulose (nanocellulose) derived from natural plants is suitable for use as a Pickering material for liquid interface stabilization for various non-toxic product formulations (e.g., the food and beverage, cosmetic, personal care, hygiene, pharmaceutical, and biomedical fields). However, the current understanding of nanocellulose-stabilized Pickering emulsion still lacks consistency in terms of the structural, self-assembly, and physio-chemical properties of nanocellulose towards the stabilization between liquid and oil interfaces. Thus, this review aims to provide a comprehensive study of the behavior of nanocellulose-based particles and their ability as a Pickering functionality to stabilize emulsion droplets. Extensive discussion on the characteristics of nanocelluloses, morphology, and preparation methods that can potentially be applied as Pickering emulsifiers in a different range of emulsions is provided. Nanocellulose's surface modification for the purpose of altering its characteristics and provoking multifunctional roles for high-grade non-toxic applications is discussed. Subsequently, the water-oil stabilization mechanism and the criteria for effective emulsion stabilization are summarized in this review. Lastly, we discuss the toxicity profile and risk assessment guidelines for the whole life cycle of nanocellulose from the fresh feedstock to the end-life of the product.
    Matched MeSH terms: Cellulose/chemistry
  5. Revalorization of selected municipal solid wastes as new precursors of "green" nanocellulose via a novel one-pot isolation system: A source perspective
    Chen YW, Lee HV
    Int J Biol Macromol, 2018 Feb;107(Pt A):78-92.
    PMID: 28860064 DOI: 10.1016/j.ijbiomac.2017.08.143
    In the present work, four types of newly chosen municipal solid wastes (Panax ginseng, spent tea residue, waste cotton cloth, and old corrugated cardboard) were studied as the promising sources for nanocellulose, which has efficiently re-engineered the structure of waste products into highly valuable nanocellulose materials. The nanocellulose was produced directly via a facile one-pot oxidative hydrolysis process by using H2O2/Cr(NO3)3 solution as the bleaching agent and hydrolysis medium under acidic condition. The isolated nanocellulose products were well-characterized in terms of chemical composition, product yield, morphological structure and thermal properties. The study has found that the crystallinity index of the obtained nanocellulose products were significantly higher (62.2-83.6%) than that of its starting material due to the successive elimination of lignin, hemicellulose and amorphous regions of cellulose, which were in good agreement with the FTIR analysis. The evidence of the successful production of nanocellulose was given by TEM observation which has revealed the fibril widths were ranging from 15.6 to 46.2nm, with high cellulose content (>90%), depending on the cellulosic origin. The physicochemical properties of processed samples have confirmed that the isolation of high purity nanocellulose materials from different daily spent products is possible. The comparative study can help to provide a deep insight on the possibility of revalorizing the municipal solid wastes into nanocellulose via the simple and versatile one-pot isolation system, which has high potential to be used in commercial applications for sustainable development.
    Matched MeSH terms: Cellulose/chemistry*
  6. Cellulose nanofibril-based aerogel derived from sago pith waste and its application on methylene blue removal
    Beh JH, Lim TH, Lew JH, Lai JC
    Int J Biol Macromol, 2020 Oct 01;160:836-845.
    PMID: 32485260 DOI: 10.1016/j.ijbiomac.2020.05.227
    Sago pith cellulose nanofibril (SPCNF) aerogel derived from sago pith waste (SPW) was successfully produced through three consecutive steps, namely dewaxing and delignification, ultra-sonication and homogenization and freeze drying. The aerogel was characterized using field emission scanning electron microscopy (FE-SEM), Fourier-transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Results of the analyses collectively showed that lignin & hemicellulose were absent in the SPCNF aerogel product which has a high crystallinity index of 88%. The diameters of individual nanofibril constituents of the SPCNF were between 15 and 30 nm and aspect ratios >1000 were observed. The SPCNF aerogel, with a density measured at 2.1 mg/cm3, was efficient in methylene blue (MB) removal with a maximum MB adsorption of 222.2 mg/g at 20 °C. The adsorption of MB onto the SPCNF aerogel was rapid and found to follow a pseudo-second-order kinetic model with the adsorption isotherm being in congruence with the Langmuir model. The SPCNF aerogel exhibited outstanding MB removal efficacies with 5 mg and 20 mg of SPCNF capable of removing over 90% and almost 99% MB, respectively. The optimized pH value and temperature for MB adsorption were determined as pH 7 and 20 °C.
    Matched MeSH terms: Cellulose/chemistry*
  7. pH-responsive CAP-co-poly(methacrylic acid)-based hydrogel as an efficient platform for controlled gastrointestinal delivery: fabrication, characterization, in vitro and in vivo toxicity evaluation
    Shah SA, Sohail M, Minhas MU, Nisar-Ur-Rehman, Khan S, Hussain Z, et al.
    Drug Deliv Transl Res, 2019 Apr;9(2):555-577.
    PMID: 29450805 DOI: 10.1007/s13346-018-0486-8
    Cellulose acetate phthalate-based pH-responsive hydrogel was synthesized for fabrication of polymeric matrix tablets for gastro-protective delivery of loxoprofen sodium. Cellulose acetate phthalate (CAP) was cross-linked with methacrylic acid (MAA) using free radical polymerization technique. Fourier transform infrared (FTIR) spectra confirmed the formation of cross-linked structure of CAP-co-poly(methacrylic acid). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed the thermal stability of polymeric networks, and scanning electron microscopy (SEM) and energy-dispersive X-ray spectrum (EDS) images unveiled that the prepared formulations were porous in nature and thus the developed formulations had shown better diffusibility. Swelling and in vitro drug release was performed at various pHs and maximum swelling and release was obtained at pH 7.4, while swelling and release rate was very low at pH 1.2 which confirmed the pH-responsive behavior of CAP-co-poly(MAA). CAP-co-poly(MAA) copolymer prevents the release of loxoprofen sodium into the stomach due to reduced swelling at gastric pH while showing significant swelling and drug release in the colon. Cytotoxicity studies revealed higher biocompatibility of fabricated hydrogel. Acute oral toxicity studies were performed for the evaluation and preliminary screening of safety profile of the developed hydrogels. Matrix tablets were evaluated for release behavior at simulated body pH. The investigations performed for analysis of hydrogels and fabricated matrix tablets indicated the controlled drug release and gastro-protective drug delivery of CAP-co-poly(MAA) hydrogels and pH-sensitive matrix tablets for targeted delivery of gastro-sensitive/irritative agents. Graphical abstract.
    Matched MeSH terms: Cellulose/chemistry
  8. Use of artificial neural networks to predict drug dissolution profiles and evaluation of network performance using similarity factor
    Peh KK, Lim CP, Quek SS, Khoh KH
    Pharm Res, 2000 Nov;17(11):1384-8.
    PMID: 11205731
    PURPOSE: To use artificial neural networks for predicting dissolution profiles of matrix-controlled release theophylline pellet preparation, and to evaluate the network performance by comparing the predicted dissolution profiles with those obtained from physical experiments using similarity factor.

    METHODS: The Multi-Layered Perceptron (MLP) neural network was used to predict the dissolution profiles of theophylline pellets containing different ratios of microcrystalline cellulose (MCC) and glyceryl monostearate (GMS). The concepts of leave-one-out as well as a time-point by time-point estimation basis were used to predict the rate of drug release for each matrix ratio. All the data were used for training, except for one set which was selected to compare with the predicted output. The closeness between the predicted and the reference dissolution profiles was investigated using similarity factor (f2).

    RESULTS: The f2 values were all above 60, indicating that the predicted dissolution profiles were closely similar to the dissolution profiles obtained from physical experiments.

    CONCLUSION: The MLP network could be used as a model for predicting the dissolution profiles of matrix-controlled release theophylline pellet preparation in product development.

    Matched MeSH terms: Cellulose/chemistry
  9. Insights into chitosan-based cellulose nanowhiskers reinforced nanocomposite material via deep eutectic solvent in green chemistry
    Chang XX, Mubarak NM, Karri RR, Tan YH, Khalid M, Dehghani MH, et al.
    Environ Res, 2023 Feb 15;219:115089.
    PMID: 36529332 DOI: 10.1016/j.envres.2022.115089
    In the present work, the synthesis of cellulose nanowhiskers (CNW)/chitosan nanocomposite films via deep eutectic solvents (DES) changing the chemical structures were carried out. It was observed that a pure chitosan film has broadband at 3180-3400 cm-1, indicating amide and hydroxyl groups. Upon CNW incorporation, the peak gets sharper and stronger and shifts to a greater wavelength. Further, the addition of DES infuses more elements of amide into the nanocomposite films. Moreover, the mechanical properties incorporating CNW filler into a chitosan matrix show an enhancement in tensile strength (TS), Young's modulus (YM), and elongation at break. The TS and YM increase while the elongation decrease as the CNW concentration increases. The YM of biocomposite films is increased to 723 MPa at 25% CNW into chitosan films. Besides, the TS has enhanced to 11.48 MPa at 15% CNW concentration in the biocomposite films. The elongation at break has decreased to 11.7% at 25% CNW concentration. Hence, incorporating CNW into the chitosan matrix via DES can still improve the mechanical properties of the nanocomposite films. Therefore, the application of DES results in a lower YM and TS as the films are hygroscopic. In conclusion, DES can be considered the new green solvent media for synthesizing materials. It has the potential to replace ionic liquids due to its biodegradability and non-toxic properties while preserving the character of low-vapour pressure. Besides that, chitosan can be used as potential material for applications in process industries, such as the biomedical and pharmaceutical industries. Thus, DES can be used as a green solvent and aim to reduce the toxic effect of chemicals on the environment during chemical production.
    Matched MeSH terms: Cellulose/chemistry
  10. Morphological, chemical and thermal analysis of cellulose nanocrystals extracted from bamboo fibre
    Rasheed M, Jawaid M, Parveez B, Zuriyati A, Khan A
    Int J Biol Macromol, 2020 Oct 01;160:183-191.
    PMID: 32454108 DOI: 10.1016/j.ijbiomac.2020.05.170
    This work investigates the extraction of cellulose nanocrystals (CNC) from bamboo fibre as an alternative approach to utilize the waste bamboo fibre. In this study, bamboo fibre was subjected to acid hydrolysis for efficient isolation of CNC from bamboo fibre. The extracted CNC's were morphologically, characterized via Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). The energy Dispersive X-rays (EDX) provided the elemental composition of the prepared CNC's and X-ray diffractometer (XRD) exhibited their crystallinity. The physiochemical analysis was done via Fourier Transform Infrared (FTIR); and their thermal analysis was revealed by Thermogravimetric Analysis (TGA) and Differential scanning calorimetry (DSC). As from their morphological investigations, rod like structures of CNC's were observed under SEM analysis with higher carbon content as demonstrated by EDX, while needle shaped CNC's were observed from TEM and AFM studies. Acid hydrolysis for 45 min resulted into higher degree of crystallinity and higher yield of CNC's about 86.96% and 22% respectively. Owing to higher quality of CNC's obtained as a result of efficient and modified techniques, these can find potential usage in nanocomposites for biomedical and food packaging application.
    Matched MeSH terms: Cellulose/chemistry*
  11. Purification, characterization and comparative studies of spray-dried bacterial cellulose microparticles
    Amin MC, Abadi AG, Katas H
    Carbohydr Polym, 2014 Jan;99:180-9.
    PMID: 24274495 DOI: 10.1016/j.carbpol.2013.08.041
    Bacterial cellulose (BC) is a biopolymer with significant potential for the development of novel materials. This work aimed to prepare and characterize BC powders from nata de coco, and assess the possible enhancement of the powder properties by spray drying. Therefore, BC powders prepared by acid treatment and mechanical processing were spray-dried, and characterized according to their morphology, flowability, thermal stability, water retention capacity, and compared with commercial microcrystalline cellulose (MCC). The powders redispersibility and suspensions rheology were also evaluated. SEM showed that spray-dried BC microparticles exhibited semispherical shape and had flow rate of 4.23 g s(-1) compared with 0.52 g s(-1) for MCC. Particle size analysis demonstrated that spray-dried BC microparticles could be redispersed. TGA showed that BC samples had higher thermal stability than MCC. Water retention capacities of BC samples were greater than MCC. These findings provide new insight on the potential applications of spray-dried BC as a promising pharmaceutical excipient.
    Matched MeSH terms: Cellulose/chemistry*
  12. Poly(lactic acid)/poly(butylene succinate) dual-layer membranes with cellulose nanowhisker for heavy metal ion separation
    Kian LK, Jawaid M, Nasef MM, Fouad H, Karim Z
    Int J Biol Macromol, 2021 Dec 01;192:654-664.
    PMID: 34655581 DOI: 10.1016/j.ijbiomac.2021.10.042
    In this study, poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) dual-layer membranes filled with 0-3 wt% cellulose nanowhisker (CNWs) were fabricated with aim to remove metal ions from wastewater. An integrated method was employed in the membrane fabrication process by combining water vapor-induced and crystallization-induced phase inversions. The membrane thickness was measured in between 11 and 13 μm, which did not pose significant flux deviation during filtration process. The 3% CNW filled membrane showed prominent and well-laminated two layers structure. Meanwhile, the increase in CNWs from 0 to 3% loadings could improve the membrane porosity (43-74%) but reducing pore size (2.45-0.54 μm). The heat resistance of neat membrane enhanced by 1% CNW but decreased with loadings of 2-3% CNWs due to flaming behavior of sulphated nanocellulose. Membrane with 3% CNW displayed the tensile strength (23.5 MPa), elongation at break (7.1%), and Young's modulus (0.75 GPa) as compared to other samples. For wastewater filtration performance, the continuous operation test showed that 3% CNW filled membrane exhibited the highest removal efficiency for both cobalt and nickel metal ions reaching to 83% and 84%, respectively. We concluded that CNWs filled dual-layer membranes have potential for future development in the removal of heavy metal ions from wastewater streams.
    Matched MeSH terms: Cellulose/chemistry*
  13. Isolation and characterization of nanocrystalline cellulose from roselle-derived microcrystalline cellulose
    Kian LK, Jawaid M, Ariffin H, Karim Z
    Int J Biol Macromol, 2018 Jul 15;114:54-63.
    PMID: 29551511 DOI: 10.1016/j.ijbiomac.2018.03.065
    Roselle fiber is a renewable and sustainable agricultural waste enriched with cellulose polysaccharides. The isolation of Nanocrystalline cellulose (NCC) from roselle-derived microcrystalline cellulose (MCC) is an alternative approach to recover the agricultural roselle plant residue. In the present study, acid hydrolysis with different reaction time was carried out to degrade the roselle-derived MCC to form NCC. The characterizations of isolated NCC were conducted through Fourier Transform Infrared Ray (FTIR), Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). As evaluated from the performed morphological investigations, the needle-like shape NCC nanostructures were observed under TEM and AFM microscopy studies, while irregular rod-like shape of NCC was observed under FESEM analysis. With 60min hydrolysis time, XRD analysis demonstrated the highest NCC crystallinity degree with 79.5%. In thermal analysis by TGA and DSC, the shorter hydrolysis time tended to produce NCC with higher thermal stability. Thus, the isolated NCC from roselle-derived MCC has high potential to be used in application of pharmaceutical and biomedical fields for nanocomposite fabrication.
    Matched MeSH terms: Cellulose/chemistry*
  14. Fulltext Highly porous regenerated cellulose hydrogel and aerogel prepared from hydrothermal synthesized cellulose carbamate
    Gan S, Zakaria S, Chia CH, Chen RS, Ellis AV, Kaco H
    PLoS One, 2017;12(3):e0173743.
    PMID: 28296977 DOI: 10.1371/journal.pone.0173743
    Here, a stable derivative of cellulose, called cellulose carbamate (CC), was produced from Kenaf (Hibiscus cannabinus) core pulp (KCP) and urea with the aid of a hydrothermal method. Further investigation was carried out for the amount of nitrogen yielded in CC as different urea concentrations were applied to react with cellulose. The effect of nitrogen concentration of CC on its solubility in a urea-alkaline system was also studied. Regenerated cellulose products (hydrogels and aerogels) were fabricated through the rapid dissolution of CC in a urea-alkaline system. The morphology of the regenerated cellulose products was viewed under Field emission scanning electron microscope (FESEM). The transformation of allomorphs in regenerated cellulose products was examined by X-ray diffraction (XRD). The transparency of regenerated cellulose products was determined by Ultraviolet-visible (UV-Vis) spectrophotometer. The degree of swelling (DS) of regenerated cellulose products was also evaluated. This investigation provides a simple and efficient procedure of CC determination which is useful in producing regenerated CC products.
    Matched MeSH terms: Cellulose/chemistry*
  15. Superabsorbent hydrogel from oil palm empty fruit bunch cellulose and sodium carboxymethylcellulose
    Salleh KM, Zakaria S, Sajab MS, Gan S, Kaco H
    Int J Biol Macromol, 2019 Jun 15;131:50-59.
    PMID: 30844455 DOI: 10.1016/j.ijbiomac.2019.03.028
    A green regenerated superabsorbent hydrogel was fabricated with mixtures of dissolved oil palm empty fruit bunch (EFB) cellulose and sodium carboxymethylcellulose (NaCMC) in NaOH/urea system. The formation of hydrogel was aided with epichlorohydrin (ECH) as a crosslinker. The resultant regenerated hydrogel was able to swell >80,000% depending on the NaCMC concentrations. The hydrogel absorbed water rapidly upon exposure to water up to 48 h and gradually declined after 72 h. The crosslinked of covalent bond of COC between dissolved EFB cellulose (EFBC) with NaCMC was confirmed with Attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy. Crystallinity and thermal stability of the hydrogel samples were depended on the concentrations of NaCMC, crosslinking, and swelling process. The strength and stability of crosslinked network was studied by examining the gel fraction of hydrogel. This study explored the swelling ability and probable influenced factors towards physical and chemical properties of hydrogel.
    Matched MeSH terms: Cellulose/chemistry*
  16. Performance of cellulose acetate - polyethersulphone blend membrane prepared using microwave heating for palm oil mill effluent treatment
    Idris A, Ahmed I, Jye HW
    Water Sci Technol, 2007;56(8):169-77.
    PMID: 17978445
    The objective of this research is to investigate the performance of blend cellulose acetate (CA)-polyethersulphone (PES) membranes prepared using microwave heating (MWH) techniques and then compare it with blend CA-PES membranes prepared using conventional heating (CH) methods using bovine serum albumin solution. The superior membranes were then used in the treatment of palm oil mill effluent (POME). Various blends of CA-PES have been blended with PES in the range of 1-5 wt%. This distinctive series of dope formulations of blend CA/PES and pure CA was prepared using N, N-dimethylformamide (DMF) as solvent. The dope solution was prepared by MW heating for 5 min at a high pulse and the membranes were prepared by phase inversion method. The performances of these membranes were evaluated in terms of pure water and permeate flux, percentage removal of total suspended solids (TSS), chemical oxygen demand (COD) and biochemical oxygen demand (BOD). The results indicate that blend membranes prepared using the microwave technique is far more superior compared to that prepared using CH. Blend membranes with 19% CA, 1-3% PES and 80% of DMF solvent were found to be the best membrane formulation.
    Matched MeSH terms: Cellulose/chemistry
  17. Stimuli-responsive bacterial cellulose-g-poly(acrylic acid-co-acrylamide) hydrogels for oral controlled release drug delivery
    Mohd Amin MC, Ahmad N, Pandey M, Jue Xin C
    Drug Dev Ind Pharm, 2014 Oct;40(10):1340-9.
    PMID: 23875787 DOI: 10.3109/03639045.2013.819882
    This study evaluated the potential of stimuli-responsive bacterial cellulose-g-poly(acrylic acid-co-acrylamide) hydrogels as oral controlled-release drug delivery carriers. Hydrogels were synthesized by graft copolymerization of the monomers onto bacterial cellulose (BC) fibers by using a microwave irradiation technique. The hydrogels were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). FT-IR spectroscopy confirmed the grafting. XRD showed that the crystallinity of BC was reduced by grafting, whereas an increase in the thermal stability profile was observed in TGA. SEM showed that the hydrogels exhibited a highly porous morphology, which is suitable for drug loading. The hydrogels demonstrated a pH-responsive swelling behavior, with decreased swelling in acidic media, which increased with increase in pH of the media, reaching maximum swelling at pH 7. The release profile of the hydrogels was investigated in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The hydrogels showed lesser release in SGF than in SIF, suggesting that hydrogels may be suitable drug carriers for oral controlled release of drug delivery in the lower gastrointestinal tract.
    Matched MeSH terms: Cellulose/chemistry*
  18. Production and modification of nanofibrillated cellulose using various mechanical processes: a review
    Abdul Khalil HP, Davoudpour Y, Islam MN, Mustapha A, Sudesh K, Dungani R, et al.
    Carbohydr Polym, 2014 Jan;99:649-65.
    PMID: 24274556 DOI: 10.1016/j.carbpol.2013.08.069
    Nanofibrillated cellulose from biomass has recently gained attention owing to their biodegradable nature, low density, high mechanical properties, economic value and renewability. Although they still suffer from two major drawbacks. The first challenge is the exploration of raw materials and its application in nanocomposites production. Second one is high energy consumption regarding the mechanical fibrillation. However, pretreatments before mechanical isolation can overcome this problem. Hydrophilic nature of nano-size cellulose fibers restricts good dispersion of these materials in hydrophobic polymers and therefore, leads to lower mechanical properties. Surface modification before or after mechanical defibrillation could be a solution for this problem. Additionally, drying affects the size of nanofibers and its properties which needs to study further. This review focuses on recent developments in pretreatments, nanofibrillated cellulose production and its application in nanopaper applications, coating additives, security papers, food packaging, and surface modifications and also for first time its drying.
    Matched MeSH terms: Cellulose/chemistry*
  19. Properties of polylactic acid composites reinforced with oil palm biomass microcrystalline cellulose
    Haafiz MK, Hassan A, Zakaria Z, Inuwa IM, Islam MS, Jawaid M
    Carbohydr Polym, 2013 Oct 15;98(1):139-45.
    PMID: 23987327 DOI: 10.1016/j.carbpol.2013.05.069
    In this work, polylactic acid (PLA) composites filled with microcrystalline cellulose (MCC) from oil palm biomass were successfully prepared through solution casting. Fourier transform infrared (FT-IR) spectroscopy indicates that there are no significant changes in the peak positions, suggesting that incorporation of MCC in PLA did not result in any significant change in chemical structure of PLA. Thermogravimetric analysis was conducted on the samples. The T50 decomposition temperature improved with addition of MCC, showing increase in thermal stability of the composites. The synthesized composites were characterized in terms of tensile properties. The Young's modulus increased by about 30%, while the tensile strength and elongation at break for composites decreased with addition of MCC. Scanning electron microscopy (SEM) of the composites fractured surface shows that the MCC remained as aggregates of crystalline cellulose. Atomic force microscopy (AFM) topographic image of the composite surfaces show clustering of MCC with uneven distribution.
    Matched MeSH terms: Cellulose/chemistry*
  20. Isolation and characterization of microcrystalline cellulose from oil palm biomass residue
    Mohamad Haafiz MK, Eichhorn SJ, Hassan A, Jawaid M
    Carbohydr Polym, 2013 Apr 2;93(2):628-34.
    PMID: 23499105 DOI: 10.1016/j.carbpol.2013.01.035
    In this work, we successfully isolated microcrystalline cellulose (MCC) from oil palm empty fruit bunch (OPEFB) fiber-total chlorine free (TCF) pulp using acid hydrolysis method. TCF pulp bleaching carried out using an oxygen-ozone-hydrogen peroxide bleaching sequence. Fourier transform infrared (FT-IR) spectroscopy indicates that acid hydrolysis does not affect the chemical structure of the cellulosic fragments. The morphology of the hydrolyzed MCC was investigated using scanning electron microscopy (SEM), showing a compact structure and a rough surface. Furthermore, atomic force microscopy (AFM) image of the surface indicates the presence of spherical features. X-ray diffraction (XRD) shows that the MCC produced is a cellulose-I polymorph, with 87% crystallinity. The MCC obtained from OPEFB-pulp is shown to have a good thermal stability. The potential for a range of applications such as green nano biocomposites reinforced with this form of MCC and pharmaceutical tableting material is discussed.
    Matched MeSH terms: Cellulose/chemistry*
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