scholarly journals Ionic liquid-plasticised composites of chitosan and hybrid 1D and 2D nanofillers

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Pei Chen ◽  
Fengwei Xie ◽  
Fengzai Tang ◽  
Tony McNally

AbstractThe focus of this research was to study the effect of combining nanofillers with different geometry and surface chemistry on the structure and properties of biopolymers as an alternative to traditional plastics. How the inclusion of 2D graphene oxide (GO) or reduced GO (rGO) combined with 1D sepiolite (SPT) or cellulose nanocrystals (CNCs) affect the structure and properties of chitosan and chitosan/carboxymethyl cellulose (CMC) materials was investigated. A 3D interconnected microstructure formed, composed of GO and SPT due to the strong interactions between these hydrophilic nanofillers. The chitosan/CMC/GO/SPT composite had the highest tensile strength (77.5 ± 1.2 MPa) and Young’s modulus (1925.9 ± 120.7 MPa). For the un-plasticised matrices, hydrophobic rGO nanosheets generally hindered the interaction of SPT or CNCs with the polysaccharides (chitosan and CMC) and consequently, composite properties were mainly determined by the rGO. However, for the chitosan matrix plasticised by 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), rGO + CNCs or rGO + SPT disrupted polymer chain interactions more effectively than the nanofillers when added alone and resulted in the chitosan being more plasticised, as shown by increased chain mobility, ductility, and surface hydrophilicity. For the [C2mim][OAc]-plasticised chitosan/CMC matrix, the advantages of including hybrid fillers, rGO + CNCs or rGO + SPT, were also obtained, resulting in higher thermal stability and surface hydrophobicity. Graphical Abstract

2012 ◽  
Vol 499 ◽  
pp. 80-84
Author(s):  
Huai Fang Wang ◽  
Wei Han Huang ◽  
Zhi Kai Wang

A series of blend films of cellulose and chitosan were prepared from 1-ethyl-3-methyl imidazole acetate ([Emim] Ac) by coagulating with ethanol. Structure, mechanical properties, thermal stability and antibacterial properties were investigated. The results showed that there were strong interactions and good compatibility between cellulose and chitosan in blend films. The blend films possess good mechanical properties and thermal stability, and the existence of chitosan endows blend films with antimicrobial property.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 571
Author(s):  
Pei Chen ◽  
Fengwei Xie ◽  
Fengzai Tang ◽  
Tony McNally

Cellulose nanocrystals (CNCs) and/or sepiolite (SPT) were thermomechanically mixed with un-plasticised chitosan and chitosan/carboxymethyl cellulose (CMC) blends plasticised with 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]). Examination of the morphology of these materials indicates that SPT aggregates were reduced when CNCs or [C2mim][OAc] were present. Inclusion of CNCs and/or SPT had a greater effect on material properties when the matrices were un-plasticised. Addition of SPT or CNCs altered the crystalline structure of the un-plasticised chitosan matrix. Moreover, a combination of SPT and CNCs was more effective at suppressing re-crystallisation. Nonetheless, the mechanical properties and surface hydrophobicity were more related to CNC/SPT–biopolymer interactions. The un-plasticised bionanocomposites generally showed increased relaxation temperatures, enhanced tensile strength, and reduced surface wettability. For the [C2mim][OAc] plasticised matrices, the ionic liquid (IL) dominates the interactions with the biopolymers such that the effect of the nanofillers is diminished. However, for the [C2mim][OAc] plasticised chitosan/CMC matrix, CNCs and SPT acted synergistically suppressing re-crystallisation but resulting in increased tensile strength.


2014 ◽  
Vol 1046 ◽  
pp. 13-17 ◽  
Author(s):  
Xiao Zhu ◽  
Yi Hong Wang ◽  
Xiao Yi Wei ◽  
Ji Hua Li ◽  
Fei Wang

In this study, the pineapple leaf cellulose membrane was prepared after being dissolved in ionic liquid (1-butyl-3-methylimidazolium chloride ([Bmim]Cl)) and high pressure microfluidization process. The chemical morphology and structure of cellulose membrane were measured by scanning electron microscope (SEM), fourier transformed infrared spectra (FT-IR), extension test and thermogravimetric analysis (TGA). Resules indicated that after microfluidizer, the surface of membrane became smoother, however the tensile strength and thermal stability of cellulose membrane was decreased due to the shearing action of microfluidizer. This would broad the application of cellulose membrane widely.


2021 ◽  
Vol 55 (2) ◽  
pp. 331-349
Author(s):  
Hannes Orelma ◽  
Atsushi Tanaka ◽  
Maija Vuoriluoto ◽  
Alexey Khakalo ◽  
Antti Korpela

AbstractTraditional particle board can generate harmful indoor air emissions due to the volatile resin-based compounds present. This study investigated the preparation of sawdust particle board using the novel ionic liquid based fusion approach with [EMIM]OAc. The dissolution parameters were investigated using the thermal optical microscopy technique. The particle board sheets were prepared by hot pressing sawdust in the presence of ionic liquid (IL) ([EMIM]OAc) and subsequently purifying the fusion sawdust matrix from the IL with methanol. The fusion process of the sawdust particles was analysed with SEM and mechanical testing. The raw materials and the produced materials were investigated with elemental analysis, FTIR, and 13C-SS-NMR. IL fusion of the sawdust required a temperature above 150 °C, similar to the glass transition temperature (tg) of lignin. At lower temperatures, strong particle fusion was not obtained. It was observed that the sawdust/IL weight ratio was an important parameter of the fusion process, and a 1:3 weight ratio resulted in the strongest particle boards with a tensile strength of up to 10 MPa, similar to commercial particle boards. The particle fusion process was also studied with a twin-screw extruder. The extrusion enhanced the fusion of the sawdust particles by increasing dissolution of the sawdust particles, which was subsequently seen in elevated tensile strength (20 MPa). The study provides a practical view of how sawdust-based particle board can be manufactured using ionic liquid-based fusion.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2084
Author(s):  
Mingkun Li ◽  
Heping Li ◽  
Hongli Liu ◽  
Zhiming Zou ◽  
Chaoyu Xie

The development of natural biomass materials with excellent properties is an attractive way to improve the application range of natural polysaccharides. Bagasse Xylan (BX) is a natural polysaccharide with various biological activities, such as antitumor, antioxidant, etc. Its physic-chemical and biological properties can be improved by functionalization. For this purpose, a novel glycidyl metharcylate/phytic acid based on a BX composite derivative was synthesized by a free radical polymerization technique with glycidyl metharcylate (GMA; GMABX) and further esterification with phytic acid (PA; GMABX-PA) in ionic liquid. The effects of the reaction conditions (i.e., temperature, time, initiator concentration, catalyst concentration, GMA concentration, PA concentration, mass of ionic liquid) on grafting rate(G), conversion rate(C) and degree of substitution(DS) are discussed. The structure of the composite material structure was confirmed by FTIR, 1H NMR and XRD. SEM confirmed the particle morphology of the composite derivative. The thermal stability of GMABX-PA was determined by TG-DTG. Molecular docking was further performed to study the combination mode of the GMABX-PA into the active site of two lung cancer proteins (5XNV, 2EB2) and a blood cancer protein (2M6N). In addition, tumor cell proliferation inhibition assays for BX, GMABX-PA were carried out using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetraz -olium bromide (MTT) method. The results showed that various reaction conditions exhibited favorable gradient curves, and that a maximum G of 56% for the graft copolymerization and a maximum DS of 0.267 can be achieved. The thermal stability was significantly improved, as demonstrated by the fact that there was still 60% residual at 800 °C. The molecular docking software generated satisfactory results with regard to the evaluated binding energy and combining sites. The inhibition ratio of GMABX-PA on NCI-H460 (lung cancer cells) reached 29.68% ± 4.45%, which is five times higher than that of BX. Therefore, the material was shown to be a potential candidate for biomedical applications as well as for use as a heat resistant material.


Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 31
Author(s):  
Hongxin Liao ◽  
Taekyung Lee ◽  
Jiangfeng Song ◽  
Jonghyun Kim ◽  
Fusheng Pan

The microstructures and mechanical properties of the Mg88.5Zn5Y6.5-XREX (RE = Yb and Ce, X = 0, 1.5, 3.0, and 4.5) (wt.%) alloys were investigated in the present study. Mg88.5Zn5Y6.5 is composed of three phases, namely, α-Mg, long-period stacking ordered (LPSO) phases, and intermetallic compounds. The content of the LPSO phases decreased with the addition of Ce and Yb, and no LPSO phases were detected in Mg88.5Zn5Y2.0Yb4.5. The alloys containing the LPSO phases possessed a stratified microstructure and exhibited excellent mechanical properties. Mg88.5Zn5Y5.0Ce1.5 exhibited the highest creep resistance and mechanical strength at both room temperature and 200 °C, owing to its suitable microstructure and high thermal stability. The yield strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature was 358 MPa. The ultimate tensile strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature and 200 °C was 453 MPa and 360 MPa, respectively.


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1064
Author(s):  
Mohd Nor Faiz Norrrahim ◽  
Hidayah Ariffin ◽  
Tengku Arisyah Tengku Yasim-Anuar ◽  
Mohd Ali Hassan ◽  
Nor Azowa Ibrahim ◽  
...  

Residual hemicellulose could enhance cellulose nanofiber (CNF) processing as it impedes the agglomeration of the nanocellulose fibrils and contributes to complete nanofibrillation within a shorter period of time. Its effect on CNF performance as a reinforcement material is unclear, and hence this study seeks to evaluate the performance of CNF in the presence of amorphous hemicellulose as a reinforcement material in a polypropylene (PP) nanocomposite. Two types of CNF were prepared: SHS-CNF, which contained about 11% hemicellulose, and KOH-CNF, with complete hemicellulose removal. Mechanical properties of the PP/SHS-CNF and PP/KOH-CNF showed an almost similar increment in tensile strength (31% and 32%) and flexural strength (28% and 29%) when 3 wt.% of CNF was incorporated in PP, indicating that hemicellulose in SHS-CNF did not affect the mechanical properties of the PP nanocomposite. The crystallinity of both PP/SHS-CNF and PP/KOH-CNF nanocomposites showed an almost similar value at 55–56%. A slight decrement in thermal stability was seen, whereby the decomposition temperature at 10% weight loss (Td10%) of PP/SHS-CNF was 6 °C lower at 381 °C compared to 387 °C for PP/KOH-CNF, which can be explained by the degradation of thermally unstable hemicellulose. The results from this study showed that the presence of some portion of hemicellulose in CNF did not affect the CNF properties, suggesting that complete hemicellulose removal may not be necessary for the preparation of CNF to be used as a reinforcement material in nanocomposites. This will lead to less harsh pretreatment for CNF preparation and, hence, a more sustainable nanocomposite can be produced.


Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 183 ◽  
Author(s):  
Marcelo Rodríguez ◽  
Luís Ayala ◽  
Pedro Robles ◽  
Rossana Sepúlveda ◽  
David Torres ◽  
...  

The unique properties of ionic liquids (ILs) drive the growing number of novel applications in different industries. The main features of ILs are high thermal stability, recyclability, low flash point, and low vapor pressure. This study investigated pure chalcopyrite dissolution in the presence of the ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate, [BMIm]HSO4, and a bromide-like complexing agent. The proposed system was compared with acid leaching in sulfate media with the addition of chloride and bromide ions. The results demonstrated that the use of ionic liquid and bromide ions improved the chalcopyrite leaching performance. The best operational conditions were at a temperature of 90 °C, with an ionic liquid concentration of 20% and 100 g/L of bromide.


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