The effect of chemical modification of wood in ionic liquids on the supermolecular structure and mechanical properties of wood/polypropylene composites
Abstract:Effects of chemical modification of wood with innovative ionic liquid on the supermolecular and morphology of wood/polypropylene composites were investigated using X-ray diffraction, hot stage optical microscopy, and differential scanning calorimetry. For the first time the chemical treatment of wood was conducted solely with newly synthesized ionic liquid, didecyldimethylammonium bis(trifluoromethylsulfonyl)imide. The modification was found to be responsible for significant changes in nucleating abilities of … Show more
“…Composites with the filler modified using the bifunctional system (EPP/silanes) are characterised by considerable amounts of the β-PP form, which is particularly evident for the PP + EPP-TEOS/OTEOS system. Literature sources [ 6 , 71 , 72 ] reported that this polymorphic form of polypropylene exhibits greater elasticity and increased impact strength compared to the α-PP form. Summing up, treatment of wood using the novel modification system generates the β-PP polymorphic form, which considerably influences values of strain and impact strength of the produced composite materials.…”
Section: Resultsmentioning
confidence: 99%
“…For this reason, it is essential to introduce certain modifications in order to improve interface interactions in the composite system. Various methods are used to enhance compatibility between lignocellulose fillers and polymer matrices, e.g., chemical modification [ 4 , 5 , 6 ], surface grafting of polymers onto fillers [ 7 ], introduction of compatibilisers such as maleated polymer [ 8 ], and treatment with coupling agents [ 9 , 10 , 11 , 12 ].…”
The article presents characteristics of wood/polypropylene composites, where the wood was treated with propolis extract (EEP) and innovative propolis-silane formulations. Special interest in propolis for wood impregnation is due to its antimicrobial properties. One propolis-silane formulation (EEP-TEOS/VTMOS) consisted of EEP, tetraethyl orthosilicate (TEOS), and vinyltrimethoxysilane (VTMOS), while the other (EEP-TEOS/OTEOS) contained EEP, tetraethyl orthosilicate (TEOS), and octyltriethoxysilane (OTEOS). The treated wood fillers were characterized by Fourier transform infrared spectroscopy (FTIR), atomic absorption spectrometry (AAS), and X-ray diffraction (XRD), while the composites were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), and optical microscopy. The wood treated with EEP and propolis-silane formulations showed resistance against moulds, including Aspergillus niger, Chaetomium globosum, and Trichoderma viride. The chemical analyses confirmed presence of silanes and constituents of propolis in wood structure. In addition, treatment of wood with the propolis-silane formulations produced significant changes in nucleating abilities of wood in the polypropylene matrix, which was confirmed by an increase in crystallization temperature and crystal conversion, as well as a decrease in half-time of crystallization parameters compared to the untreated polymer matrix. In all the composites, the formation of a transcrystalline layer was observed, with the greatest rate recorded for the composite with the filler treated with EEP-TEOS/OTEOS. Moreover, impregnation of wood with propolis-silane formulations resulted in a considerable improvement of strength properties in the produced composites. A dependence was found between changes in the polymorphic structures of the polypropylene matrix and strength properties of composite materials. It needs to be stressed that to date literature sources have not reported on treatment of wood fillers using bifunctional modifiers providing a simultaneous effect of compatibility in the polymer-filler system or any protective effect against fungi.
“…Composites with the filler modified using the bifunctional system (EPP/silanes) are characterised by considerable amounts of the β-PP form, which is particularly evident for the PP + EPP-TEOS/OTEOS system. Literature sources [ 6 , 71 , 72 ] reported that this polymorphic form of polypropylene exhibits greater elasticity and increased impact strength compared to the α-PP form. Summing up, treatment of wood using the novel modification system generates the β-PP polymorphic form, which considerably influences values of strain and impact strength of the produced composite materials.…”
Section: Resultsmentioning
confidence: 99%
“…For this reason, it is essential to introduce certain modifications in order to improve interface interactions in the composite system. Various methods are used to enhance compatibility between lignocellulose fillers and polymer matrices, e.g., chemical modification [ 4 , 5 , 6 ], surface grafting of polymers onto fillers [ 7 ], introduction of compatibilisers such as maleated polymer [ 8 ], and treatment with coupling agents [ 9 , 10 , 11 , 12 ].…”
The article presents characteristics of wood/polypropylene composites, where the wood was treated with propolis extract (EEP) and innovative propolis-silane formulations. Special interest in propolis for wood impregnation is due to its antimicrobial properties. One propolis-silane formulation (EEP-TEOS/VTMOS) consisted of EEP, tetraethyl orthosilicate (TEOS), and vinyltrimethoxysilane (VTMOS), while the other (EEP-TEOS/OTEOS) contained EEP, tetraethyl orthosilicate (TEOS), and octyltriethoxysilane (OTEOS). The treated wood fillers were characterized by Fourier transform infrared spectroscopy (FTIR), atomic absorption spectrometry (AAS), and X-ray diffraction (XRD), while the composites were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), and optical microscopy. The wood treated with EEP and propolis-silane formulations showed resistance against moulds, including Aspergillus niger, Chaetomium globosum, and Trichoderma viride. The chemical analyses confirmed presence of silanes and constituents of propolis in wood structure. In addition, treatment of wood with the propolis-silane formulations produced significant changes in nucleating abilities of wood in the polypropylene matrix, which was confirmed by an increase in crystallization temperature and crystal conversion, as well as a decrease in half-time of crystallization parameters compared to the untreated polymer matrix. In all the composites, the formation of a transcrystalline layer was observed, with the greatest rate recorded for the composite with the filler treated with EEP-TEOS/OTEOS. Moreover, impregnation of wood with propolis-silane formulations resulted in a considerable improvement of strength properties in the produced composites. A dependence was found between changes in the polymorphic structures of the polypropylene matrix and strength properties of composite materials. It needs to be stressed that to date literature sources have not reported on treatment of wood fillers using bifunctional modifiers providing a simultaneous effect of compatibility in the polymer-filler system or any protective effect against fungi.
“…Nowadays, ionic liquids are used mainly to dissolve or modify biomass and cellulose (Brandt et al 2013;Ghasemi et al 2017;Borysiak et al 2018), but there is also a growing interest in the use of ionic liquids for the direct production of nanometric cellulose. Swatloski et al (2002) proved that cellulose can be dissolved, without any previous activation of pretreatment, in e.g.…”
In this paper three newly synthesized imidazolium ionic liquids with different structures of cations were used for hydrolysis of cellulose. It was found that type of the cation has a great influence on particle size and dispersity of produced cellulosic materials. The use of an ionic liquid with a cation with an aliphatic substituent resulted in filler characterized with wide dispersity range and some particles larger than 2 lm. Introduction of methyl group into imidazolium ring was responsible for production of particles below 350 nm. Such particles were obtained also during hydrolysis of cellulose with ionic liquid containing a benzyl substituent with that difference that in this case particles had definitely narrower dispersity range. Moreover, type of the ionic liquid used affected crystallinity degree of the produced Electronic supplementary material The online version of this article (
“…It is well known that the stronger interphase interactions resulting from modification of wood with ILs are responsible for the increase of water stability in such composites. 26 Besides, synergic with the improved interfacial adhesion between the components, the presence of the hydrophobic ILs could act as a supplementary barrier for water penetration into the structure of the material. 25 The importance of this synergic mechanism is sustained by the fact that the IL-SCN can promote higher moisture stabilization for the WPCs in comparison with IL-Cl, probably due to its more pronounced hydrophobic character.…”
Section: Resultsmentioning
confidence: 99%
“…It can be stated that chemical modification of wood not only enhanced the adhesion between polymer matrix and filler but also limited the amount of voids present in the composites and thus had an effect on its dimensional stability. 25,26 Figure 7.Thickness swelling of untreated and IL-treated composite boards.…”
In this investigation, the effect of ionic liquids (ILs) pretreatment on the interfacial behavior, physical, and thermal properties of compression-molded composite boards produced from wood flour and high-density polyethylene was studied. Firstly, wood flour was pretreated with with two types of synthesized ILs, namely 1-(3-trimethoxysilylpropyl)-3-methylimidazolium chloride (IL-Cl) and 1-(3-trimethoxysilylpropyl)-3-methylimidazolium thiocyanate (IL-SCN). Thereafter, the interfacial strength, weight loss, water absorption, and thickness swelling of the specimens prepared from untreated and ILs-treated were evaluated. Further, the chemical treatment of wood flour with ILs was tracked by Fourier transform infrared spectroscopy. The morphological aspects of the specimens were characterized using Field Emission Scanning Electron Microscope (FESEM). Results demonstrated that the strong interaction between the wood flour and high-density polyethylene occurred in the presence of ILs pretreatment, which corresponded with the minimum amounts of adhesion factor. The tan δ peak was shifted to higher temperature for the modified samples than unmodified ones. It was noted that thermal stability of the composite boards improved as a result of ILs pretreatment. The residual weight in temperature of 600℃ was increased to 21.09% and 17.28% for the composite panels made from IL-SCN- and IL-Cl-treated wood, respectively, as compared to a residual mass of 16.35% for the composite based on untreated wood. Furthermore, physical testing revealed that the specimens produced from ILs-treated wood exhibited superior water resistance and dimensional stability compared to that of untreated ones.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
