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  • 1.
    García Vogel, Andres
    et al.
    Luleå University of Technology. Fiber and Particle Engineering, University of Oulu, Finland.
    Hooshmand, Saleh
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Fiber and Particle Engineering, University of Oulu, Finland.
    All-cellulose composites based on wet-spun cellulose fibers reinforced with cellulose nanocrystals and halloysite nanoclay2017In: ICCM21 Proceedings, ICCM, International Committee on Composite Materials , 2017, article id 3751Conference paper (Refereed)
    Abstract [en]

    The aim of the study was to develop biobased and lightweight composites with unidirectional cellulose fibers without a matrix polymer, so called all-cellulose composites with excellent mechanical properties. Continuous cellulose fibers are currently gaining interest for composite applications and if these fibers can be welded together without using a polymer resin it would result in an environmental friendly composite material. The regenerated fibers were prepared using wet spinning of DMAc/LiCl dissolved cellulose where cellulose nanocrystals (CNC) and halloysitenanotubes (HNT) were used as reinforcements. The loading of the nanomaterials into the dissolved cellulose was between 2 to 20 %. The preliminary results showed that the addition of both CNC and HNT improved the mechanical properties of the regenerated cellulose fibers. It was also seen that low concentration of the nanomaterials was more effective reinforcement than high concentration. Also, the HNT showed slightly better improvement compared to the CNC). The spun nanocomposite fibers were directly wound to a roll after the wet spinning, compression molded to compositesheet and dried. The all-cellulose composites mechanical properties as well as microstructure including nanomaterials orientation in the spun fibers were studied and composites mechanical properties are compared with theoretical models. 

  • 2.
    Hooshmand, Saleh
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Process and properties of continuous fibers based on cellulose nanocrystals and nanofibers2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In recent years, composites made from natural fibers based on cellulose have received increasing attention since they have a low environmental impact and good mechanical properties. However, these fibers are short and discontinuous and the conventional spinning techniques used for these fibers results in continuous yarns with mechanical properties considerably lower than that of the single fibers. The aim of this work was to prepare continuous fibers where nano-sized cellulose crystals and cellulose nanofibers were used to improve the fiber properties. Two different strategies have been used to reach this aim. In the first study, bio-based fibers of cellulose acetate butyrate (CAB) and cellulose nanocrystals (CNC) using triethyl citrate (TEC) as plasticizer were prepared by melt spinning. Two different dispersion techniques were studied. In the first technique, the water content of the CNC suspension was reduced and exchanged to ethanol using centrifugation. In the second, the water in the CNC suspension was completely exchanged to ethanol by a sol-gel process. Results showed that tensile modulus and tensile strength of the nanocomposite fibers produced with the first technique were lower than CAB-TEC fibers, but the fibers produced by the sol-gel process showed an increase in the tensile modulus and had no decrease in the strength. Optical microscopy of the fibers indicated less aggregations in the sol-gel prepared materials. The results indicate that the sol-gel process is enhancing the dispersion of cellulose nanocrystals and can be a suitable way to prepare nanocomposite fibers. The second study is an extension of the first study. Here the effect of weight concentration of CNC and fiber drawing was studied. The microscopy studies showed that the addition of CNC in CAB resulted in defect-free and smooth fiber surfaces. An addition of 10 wt% CNC enhanced the storage modulus and increased the tensile strength and Young’s modulus. Fiber drawing improved the mechanical properties further. In addition, a micromechanical model of the composite material was used to estimate the stiffness and showed that theoretical values were exceeded for the lower concentration of CNC but not reached for the higher concentration. In conclusion, this dispersion technique combined with melt spinning can be used to produce all-cellulose nanocomposites fibers and that both the increase in CNC volume fraction and the fiber drawing increased the mechanical performance. In the third study a different strategy was used. Here low cost and environmentally friendly continuous fibers of native cellulose were prepared by dry spinning an aqueous suspension of cellulose nanofibers (CNF). The CNF were extracted from banana rachis, a bio-residue from banana cultivation in Columbia. The effect of spinning rate and CNF concentration on the mechanical properties of the fibers were investigated. The results showed that there was a relationship between the spinning rate and concentration. The modulus of the fibers was increased from 7.7 to 12.6 GPa and the strength increased from 131 to 222 MPa when the lowest concentration and highest speed was used. This improvement is believed to be due to an increased orientation of the CNF in the fiber. A minimum concentration of 6.5 wt% was required for continuous fiber spinning. However, this relatively high concentration is thought to limit the orientation of the CNF in the fiber. The process used in this last study has a good potential for up-scaling providing a continuous fiber production with well-controlled speed but further work is required to increase the orientation and subsequently the mechanical properties.The results from these three studies shows that it is possible to spin continuous fibers where nanocellulose is used as a reinforcing agent. It is also shown that the dispersion and alignment of the nanocellulose plays a key role in improving the mechanical properties.

  • 3.
    Hooshmand, Saleh
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Processing of continuous fibers based on nanocellulose: Influence of dispersion and orientation on mechanical properties2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of the work was to prepare continuous bio-based fibers where nano-sized cellulose was used to improve the mechanical properties. Two different strategies were used to reach this aim, melt-spinning of thermoplastic fibers reinforced with nanocellulose and dry-spinning of cellulose nanofibers without solvent or chemicals. In the first strategy, melt-spun fibers were reinforced with cellulose nanocrystals. First, nanocomposite fibers of cellulose acetate butyrate (CAB) reinforced with cellulose nanocrystals (CNC) and plasticized with triethyl citrate (TEC) were prepared. Two different techniques for dispersing CNC were compared: a process of solvent exchange of the aqueous CNC suspension to ethanol by centrifugation and sol-gel process. The mechanical properties and microscopy results indicated that the sol-gel process enhanced the dispersion. Subsequently the effect of CNC concentration and solid-state drawing (SSD) was studied. The results were defect-free and smooth fiber surfaces, in which an addition of 10 wt% CNC and drawing increased the tensile strength and Young’s modulus by 43% and 134% compared to the as-spun unreinforced fibers. This melt spinning process was also used to process melt-spun nanocomposite fibers of polylactic acid (PLA) and CNC. In this study the effect of surface modification of the CNC as well as the melt draw ratio (MDR) was investigated. The results showed that the increased MDR together with the surface modification resulted in better mechanical properties. In the second strategy, continuous fibers of native cellulose nanofibers (CNF) were prepared by dry-spinning. First, the effect of the spinning rate and the CNF concentration on the mechanical properties were investigated. The highest orientation and mechanical properties were achieved by combining a low CNF concentration with a high spin rate. The modulus of the fibers increased from 7.7 to 12.6 GPa and the strength form 131 to 222 MPa. After this, to further improve the orientation of the CNF, a small amount of hydroxyethylene cellulose (HEC) was used as a binder and the fibers were cold drawn after the spinning. The results showed that the addition of the binder and cold drawing increased the modulus and strength by 76% and 73% being 15 GPa and 260 MPa respectively. The results also confirmed that dry-spinning has potential for up-scaling, providing a continuous fiber production with well-controlled speed.These studies demonstrated that the dispersion and alignment of nanocellulose in spun fibers play key roles in improving the mechanical properties of these continuous bio-based fibers.

  • 4.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Aitomäki, Yvonne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Berglund, Linn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Enhanced alignment and mechanical properties through the use of hydroxyethyl cellulose in solvent-free native cellulose spun filaments2017In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 150, p. 79-86Article in journal (Refereed)
    Abstract [en]

    In this study, the addition of hydroxyethyl cellulose (HEC) in cellulose nanofiber filaments is shown to improve the solvent-free processing and mechanical properties of these biobased fibers as well as their compatibility with epoxy. An aqueous dope of cellulose nanofiber (CNF) with HEC was spun and the resulting filaments cold-drawn. The HEC increased the wet strength of the dope allowing stable spinning of low concentrations of CNF. These lower concentrations promote nanofiber alignment which is further improved by cold-drawing. Alignment improves the modulus and strength and an increase of over 70% compared to the as-spun CNF only filaments was achieved. HEC also decreases hydrophilicity thus increasing slightly the interfacial shear strength of the filaments with epoxy resin. The result is continuous biobased fibers with improved epoxy compatibility that can be prepared in an upscalable and environmentally friendly way. Further optimization is expected to increase draw ratio and consequently mechanical properties.

  • 5.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Aitomäki, Yvonne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Dry-spinning of continuous cellulose fibers using only nanofibers from a bio-residue2014Conference paper (Refereed)
    Abstract [en]

    IntroductionFibers are widely used in polymer composites and the highest mechanical properties are achieved when fibers are continuous and aligned in the direction of the applied load. For this reason continuous glass fiber composites are commonly used in structural applications. These glass fibers have high stiffness (70 GPa) and strength (3400 MPa) but have a high environmental impact. An alternative is to use natural fibers since they have a low environmental impact and good mechanical properties, e.g. flax fibers have a stiffness of 70 GPa and strength of 900 MPa. However, natural fibers are short and discontinuous and conventional spinning results in highly twisted yarns, which negatively impact the mechanical properties of the composites1. One solution to overcome these limitations is to prepare continuous biobased man-made fibers from cellulose. Thermoplastic cellulose-based biopolymers such as cellulose acetate butyrate (CAB) can be melt-spun but the low mechanical properties of these fibers make them unsuitable for use in structural composites. Nanoreinforcing as well as aligning the polymer chains and nanoreinforcements were investigated but the improvements in the final properties of CAB nanocomposites fibers were still far below the desired values2,3. Regenerated cellulosic fibers are another type of continuous cellulosic man-made fibers but again their mechanical properties are lower than that of native cellulose, e.g. Lyocell has a stiffness of 16 GPa and strength of 660 MPa. Therefore, of interest is the manufacture of aligned continuous native cellulose fibers. Cellulosic fibers have been prepared by simply wet spinning tempo-mediated oxidized cellulose nanofibers (CNF) through a syringe into an organic liquid 4, 5. Though, high mechanical properties of the fibers have been reported, tempo-mediated oxidation and using solvents for precipitation does not make the process economical. In the current study, low-cost continuous cellulose fibers from a bio-residue CNF without additional chemicals and solvents were prepared. The effect of spinning rates as well as the effect of CNF concentration on the mechanical properties of the fibers was investigated.ExperimentalCellulose nanofibers were extracted from bleached banana rachis waste using ultra-fine grinder (Masuko Sangyo Co., Saitama, Japan). The bleached fibers were supplied by ECLIPSE project. A suspension of 2wt% was concentrated to different concentrations (8, 10 and 12 wt%) using centrifugation. Dry spinning of the fibers were carried out at three spinning rates (72, 144 and 216 mm/s) using a Rheo-tester 1000 (Göttfert, Buchen, Germany) equipped with a 1 mm single hole die with length of 20 mm. The spun fibers were then collected and mounted on glass sheets before being dried at room temperature followed by oven drying to remove any remaining moisture (Fig. 1). For comparison a nanopaper from the CNF was also made by vacuum filtration and drying.References1. Goutianos et al.: Appl Compos Mater, 2006, 13 199-215.2. Hooshmand et al.: Plast Rubber Compos, 2014, 43 (1) 15-24.3. Hooshmand et al.: Cellulose, 2014 accepted.4. Walter et al.: Adv Mater, 2011, 23 2924-2928.5. Iwamoto et al.: Biomacromolecules, 2011, 12 831-836.AcknowledgementsThe authors thank Bio4Energy for financial support of this project as well as ECLIPSE project (grant agreement nº: 280786) for the banana nanofibers.

  • 6.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Aitomäki, Yvonne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Exploiting the self-assembly of cellulose nanofibers in wet and dry spun fibers2014Conference paper (Refereed)
    Abstract [en]

    In the current study, self-assembled cellulose fibers were prepared by wet spinning and dry spinning of the cellulose nanofibers (CNF). The CNF were prepared using a low-cost and energy efficient procedure from a bio-residue source without using any additional chemical treatments. Different concentrations of CNF in water were simply wet spun into an acetone coagulation bath as well as dry spun into the air. These different spinning conditions as well as the effect of concentration and shear force on the orientation of the CNF in the spun fibres and mechanical properties of these fibers were investigated. Using viscosity measurements, the theoretical shear forces are calculated and related to orientation and the mechanical properties. It is this shearing during the loosely bound suspension state of the CNF that is thought to allow an increase in orientation of the CNF in the spun fibre. This orientation is then maintained by the presence of the hydroxyl group on the surface of the CNF resulting in hydrogen bonds between the CNF. This self-assembly of the more orientated CNF as the fibres dry provided high stiffness and low ductility to the resulting fiber. These characteristics and the fact that they are continuous fibres make them very suitable to use in the structural composites. The fibers were further characterized regarding viscoelasticity behavior and thermal properties as well as crystallinity and microstructure.

  • 7.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Aitomäki, Yvonne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Influence of Matrix and Cold-drawing on Dry Spun Filaments of Cellulose Nanofibers2015Conference paper (Refereed)
    Abstract [en]

    In this study, two different types of single filament fibers were prepared by dry-spinning an aqueous suspension of cellulose nanofibers (CNF) as well as CNF and water-soluble hydroxyethyl cellulose (HEC) suspension. The filaments were prepared using a capillary rheometer with a single-hole die. Based on our previous study1, the lowest spinnable concentration was used to increase the CNF orientation induced by the shear force in the die. To further increase the orientation of the CNF in the fibers and subsequently increase their mechanical properties, the semi-dried fibers were cold-drawn to ≈4%. The effect of drawing on both CNF-only and CNF-HEC nanocomposite fibers was investigated. The addition of HEC improved the processability of the fibers and allowed a lower spinnable concentration (≈4.5wt%) to be used compared to the CNF-only fiber (≈7wt%). The HEC improved the modulus, strength and the strain of the non-drawn CNF-HEC fiber compared to the CNF-only fiber. The higher modulus and strength of the CNF-HEC fiber is thought to be due to an increase in orientation of CNF in the fiber because of the lower concentration of the suspension. The drawn CNF-HEC fiber showed further improved in the mechanical properties, with a modulus of 15 GPa and strength of 260 MPa, an increase of 76% and 72 % respectively, compared to undrawn CNF-only fiber. The continuous nature of these nanocomposites fibers and their characteristics mean they have potential for use in fiber-reinforced composites.

  • 8.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Aitomäki, Yvonne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Norberg, Nicholas
    PANalytical.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Dry-Spun Single-Filament Fibers Comprising Solely Cellulose Nanofibers from Bioresidue2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 23, p. 13022-13028Article in journal (Refereed)
    Abstract [en]

    We demonstrated that low-cost and environmentally friendly filaments of native cellulose can be prepared by dry spinning an aqueous suspension of cellulose nanofibers (CNF). The CNF were extracted from banana rachis, a bioresidue from banana cultivation. The relationship between spinning rate, CNF concentration, and the mechanical properties of the filaments were investigated and the results showed that the modulus of the filaments was increased from 7.8 to 12.6 GPa and the strength increased from 131 to 222 MPa when the lowest concentration and highest speed was used. This improvement is believed to be due to an increased orientation of the CNF in the filament. A minimum concentration of 6.5 wt % was required for continuous filament spinning using the current setup. However, this relatively high concentration is thought to limit the orientation of the CNF in the filament. The process used in this study has a good potential for upscaling providing a continuous filament production with well-controlled speed, but further work is required to increase the orientation and subsequently the mechanical properties.

  • 9.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Aitomäki, Yvonne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Skrifvars, Mikael
    School of Engineering, University of Borås.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    All-cellulose nanocomposite fibers produced by melt spinning cellulose acetate butyrate and cellulose nanocrystals2014In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, no 4, p. 2665-2678Article in journal (Refereed)
    Abstract [en]

    Bio-based continuous fibers were prepared by melt spinning cellulose acetate butyrate (CAB), cellulose nanocrystals (CNC) and triethyl citrate. A CNC organo-gel dispersion technique was used and the prepared materials (2 and 10 wt% CNC) were melt spun using a twin-screw micro-compounder and drawn to a ratio of 1.5. The microscopy studies showed that the addition of CNC in CAB resulted in defect-free and smooth fiber surfaces. An addition of 10 wt% CNC enhanced the storage modulus and increased the tensile strength and Young's modulus. Fiber drawing improved the mechanical properties further. In addition, a micromechanical model of the composite material was used to estimate the stiffness and showed that theoretical values were exceeded for the lower concentration of CNC but not reached for the higher concentration. In conclusion, this dispersion technique combined with melt spinning can be used to produce all-cellulose nanocomposites fibers and that both the increase in CNC volume fraction and the fiber drawing increased the mechanical performance

  • 10.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    cho, Sung-woo
    University of Borås.
    Skrifvars, Mikael
    University of Borås.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Melt spinning of cellulose acetate butyrate (CAB) nanocomposite fibers reinforced by cellulose nanowhiskers (CNW)2013Conference paper (Refereed)
    Abstract [en]

    Bio-based continuous fibers were processed by melt spinning of cellulose acetate butyrate (CAB) and cellulose nanowhiskers (CNW) as well as environmental friendly plasticizer, triethyl citrate (TEC). Homogeneous dispersion of the CNW in CAB was achieved by solvent exchange to ethanol using sol-gel process. The appropriate amounts of well dispersed CNW organo-gel (2 and 10 wt%) as well as 15 wt% TEC were compounded with the dissolved CAB in ethanol followed by magnetic string, solution casting and grinding. Melt spinning of compounded CAB/TEC and CAB/TEC/CNW were carried out using a twin-screw micro extruder in continuous mode to decrease the residence time of materials and avoid thermal degradation. Afterwards, the fibers were solid-state drawn to enhance the mechanical properties. The addition of the CNW restricted the drawability of the fibers to a factor of 1.5. The tensile test data showed that 2 wt% CNW had no noticeable effect on modulus and tensile strength of the fibers while 10 wt% CNW increased the modulus and tensile strength by 58% and 36% respectively. Drawing, in general, provided greater stiffness and strength but sacrificed the ductility of the fibers. The microscopy studies showed that the fiber diameters were in the range of 350-450 μm for as-spun fibers and 300-350 μm for drawn fibers and no defect and increased surface roughness could be detected on the surface of the both as-spun and drawn composite fibers. Furthermore, The thermal properties, viscoelastic behavior as well as crystallinity properties of the fibers were characterized by TGA, DMTA and XRD.

  • 11.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Cho, Sung-Woo
    University of Borås.
    Skrifvars, Mikael
    University of Borås.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Melt spun cellulose nanocomposite fibres: comparison of two dispersion techniques2014In: Plastics, rubber and composites, ISSN 1465-8011, E-ISSN 1743-2898, Vol. 43, no 1, p. 15-24Article in journal (Refereed)
    Abstract [en]

    Bio-based continuous fibers were processed by melt spinning of cellulose acetate butyrate (CAB) and cellulose nanowhiskers (CNW) as well as environmental friendly plasticizer, triethyl citrate (TEC). Homogeneous dispersion of the CNW in CAB was achieved by solvent exchange to ethanol using sol-gel process. The appropriate amounts of well dispersed CNW organo-gel (2 and 10 wt%) as well as 15 wt% TEC were compounded with the dissolved CAB in ethanol followed by magnetic string, solution casting and grinding. Melt spinning of compounded CAB/TEC and CAB/TEC/CNW were carried out using a twin-screw micro extruder in continuous mode to decrease the residence time of materials and avoid thermal degradation. Afterwards, the fibers were solid-state drawn to enhance the mechanical properties. The addition of the CNW restricted the drawability of the fibers to a factor of 1.5. The tensile test data showed that 2 wt% CNW had no noticeable effect on modulus and tensile strength of the fibers while 10 wt% CNW increased the modulus and tensile strength by 58% and 36% respectively. Drawing, in general, provided greater stiffness and strength but sacrificed the ductility of the fibers. The microscopy studies showed that the fiber diameters were in the range of 350-450 μm for as-spun fibers and 300-350 μm for drawn fibers and no defect and increased surface roughness could be detected on the surface of the both as-spun and drawn composite fibers. Furthermore, The thermal properties, viscoelastic behavior as well as crystallinity properties of the fibers were characterized by TGA, DMTA and XRD.

  • 12.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Cho, Sung-Woo
    University of Borås.
    Skrifvars, Mikael
    University of Borås.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Preparation of bio-composite fibers by melt spinning of cellulose acetate butyrate (CAB) and cellulose nanowhiskers (CNW)2012Conference paper (Other academic)
  • 13.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Manufacturing and characterization of melt spun and wet spun bionanocomposite fibers2012Conference paper (Other academic)
  • 14.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nordin, Jan
    Luleå University of Technology, External.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Development of Ceramic Foams Containing Platinum Nanoparticles as the Catalyst2019Conference paper (Refereed)
    Abstract [en]

    The exhaust gases contribute significantly to global warming, but without a catalytic converter, exhaust gases would be even more polluting. Therefore, having a catalytic metal such as platinum nanoparticles on the surface of the pore walls in ceramic foams is a practical way to remove particulate matters and to have an effective catalytic converter in one. The porous structure of the foam filters the particulate matters and the high specific surface area of the Pt nanoparticles in the pores speed up the reactions. The role of platinum is to oxidize carbon monoxide (CO) and hydrocarbons (HC) to form carbon dioxide (CO2) and water vapor (H2O). In this study, The Pt nanoparticles were coated on the surface of the thermally expandable microspheres (Expancel). The Energy-dispersive X-ray spectroscopy (EDS) and Ultraviolet-visible spectroscopy (UV-Vis) confirmed the successful adsorption of Pt on the Expancel surface. In the next step, alumina foams prepared by the gel-casting technique using Pt-coated Expancels as the sacrificial template. The EDS confirmed the successful transfer of the Pt nanoparticles to the pore walls of the foam. The morphology and the porosity of the foams were studied using SEM and X-ray microtomography. Moreover, the compressive strength of the prepared sample in form of the green body, debinded and sintered was measured.  The results showed a promising way to design ceramic-based bi-functional foams for eliminating dust and converting harmful gases to nontoxic gases simultaneously.

  • 15.
    Hooshmand, Saleh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nordin, Jan
    Akzo Nobel Pulp and Performance Chemicals AB, Expancel, Sundsvall, Sweden.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Porous alumina ceramics by gel casting: Effect of type of sacrificial template on the properties2019In: International Journal of Ceramic Engineering & Science, ISSN 2578-3270Article in journal (Refereed)
    Abstract [en]

    The effect of type of sacrificial template on the processing and properties of porous alumina ceramics was investigated. Two templates, (a) hollow pre‐expanded polymer spheres (Expancel) and (b) dense glassy carbon, were used to prepare porous alumina ceramics by gel casting. The results showed that the burnout of sacrificial expandable polymer microspheres from alumina ceramics was 10 times faster than glassy carbon without compromising the compressive strength. Moreover, the effect of the size of the porous ceramic component during the burnout showed that the template decomposition and the escape of the formed gases took a longer time for the thicker specimens than the thinner one and it was significant in case of glassy carbon. It was found that the burnout of expandable microspheres could happen at a faster rate, and the time of the burnout cycle could be reduced significantly to save energy while keeping the mechanical strength twice as high than porous alumina ceramics after burnout of glassy carbon. Furthermore, the CO2 emissions during the burnout of sacrificial templates and the microstructure of the prepared porous alumina were compared for these two types of sacrificial templates. The prepared foams with pre‐expanded microspheres showed potential for being used in industrial applications, where the decreasing of the released gases is critical for saving time and energy for the fabrication of large ceramic parts.

  • 16. Hooshmand, Saleh
    et al.
    Soroudi, Azadeh
    University of Borås.
    Skrifvars, Mikael
    University of Borås.
    Electro-conductive composite fibers by melt spinning of polypropylene/polyamide/carbon nanotubes2011In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 161, no 15-16Article in journal (Refereed)
    Abstract [en]

    In this study, the blends of polypropylene/polyamide with carbon nanotubes (CNTs) have been prepared and melt spun to as-spun and drawn fibers. Thermal analysis showed that increasing the polyamide content, decreased the degree of crystallinity in the blends. Characterization of fibers showed that both conductivity and tensile strength have been improved by increasing the amount of polyamide in the blends as well as the melt blending temperature; furthermore, the morphology, electrical and mechanical properties of the blends were significantly influenced by adding 1 phr compatibilizer to the blend. The comparison between as-spun fibers and drawn fibers proved that although mechanical properties were improved after drawing, the electrical conductivity was decreased from the order of E−02 to E−06 (S/cm), due to applied draw-ratio of three.

  • 17.
    Mujica-Garcia, Alicia
    et al.
    Dipartimento di Ingegneria Civile e Ambientale, Università di Perugia , Instituto de Ciencia y Tecnología de Polímeros, ICTP-CSIC, Spain.
    Hooshmand, Saleh
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Skrifvars, Mikael
    School of Engineering, University of Borås.
    Kenny, Jose M.
    Dipartimento di Ingegneria Civile e Ambientale, Università di Perugia , Instituto de Ciencia y Tecnología de Polímeros, ICTP-CSIC, Spain.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Peponi, Laura
    Instituto de Ciencia y Tecnología de Polímeros, ICTP-CSIC, Spain.
    Poly(lactic acid) melt-spun fibers reinforced with functionalized cellulose nanocrystals2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 11, p. 9221-9231Article in journal (Refereed)
    Abstract [en]

    Poly(lactic acid)-cellulose nanocrystals (PLA/CNC) nanocomposite fibers with 1% weight fraction of nanocrystals were prepared by melt-spinning. In order to improve the compatibility between the PLA and the CNC, PLLA chains were grafted onto the CNC surface using a “grafting from” reaction. For comparison, melt-spun PLA fibers and nanocomposites with unmodified CNC were also prepared. The morphology, thermal and mechanical properties of the fibers with different draw ratios were evaluated. The results of this research show that the surface modification together with drawing resulted in improved fiber properties, which is expected to depend on the alignment of the CNC and of the PLA molecular chains. The modification is also expected to lead to a flexible interface which also leads to more stretchable fibers. The main conclusion is that PLLA grafting is a very promising way to improve the dispersion of CNC in PLA, creating an interfacial adhesion between the phases and making possible to spun fibers which can be drawn with improved mechanical performance.

  • 18.
    Oksman, Kristiina
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Aitomäki, Yvonne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Siquiera, Gilberto
    Applied Wood Materials Laboratory, Swiss Federal Laboratories for Materials Science and Technology (EMPA), CH-8600 Dübendorf.
    Zhou, Qi
    School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm.
    Butylina, Svetlana
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Tanpichai, Supachok
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Zhou, Xiaojian
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hooshmand, Saleh
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Review of the recent developments in cellulose nanocomposite processing2016In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 83, p. 2-18Article in journal (Refereed)
    Abstract [en]

    This review addresses the recent developments of the processing of cellulose nanocomposites, focusing on the most used techniques, including solution casting, melt-processing of thermoplastic cellulose nanocomposites and resin impregnation of cellulose nanopapers using thermoset resins. Important techniques, such as partially dissolved cellulose nanocomposites, nanocomposite foams reinforced with nanocellulose, as well as long continuous fibers or filaments, are also addressed. It is shown how the research on cellulose nanocomposites has rapidly increased during the last 10 years, and manufacturing techniques have been developed from simple casting to these more sophisticated methods. To produce cellulose nanocomposites for commercial use, the processing of these materials must be developed from laboratory to industrially viable methods.

  • 19.
    Vargas, Natalia Herrera
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hooshmand, Saleh
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mathew, Aji P.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Spinning of continuous biofibers reinforced with cellulose nanocrystals2013In: Production and Applications of Cellulose Nanomaterials, TAPPI Press, 2013, p. 115-118Chapter in book (Refereed)
    Abstract [en]

    Our aim has been to produce continuous biofibers and use nanocrystals to improve the properties. Cellulose nanocomposite fibers were prepared by melt spinning of cellulose acetate butyrate (CAB), cellulose nanocrystals (CNCs) and triethyl citrate (TEC) as well as electro spinning of cellulose acetate (CA) and CNCs. Different characterization techniques such as tensile testing, DMA, TGA, SEM and AFM were used to study the properties of the obtained nanocompiste fibers. The results showed that sol-gel technique successfully dispersed CNCs in the CAB matrix, therefore; an improvement in the mechanical properties of the melt spun bionanocomposite fibers were achieved. Likewise, the addition of CNCs into CA matrix generated an improvement in the storage modulus of the random oriented electrospun fibers. Aligned CA- fibers and nanocomposite fibers were successfully electrospun. A tendency to decrease the fiber diameter with the addition of CNCs was found for the both types of electrospun nanocomposite fibers.

1 - 19 of 19
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