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1.
Environmentally-friendly SPI/cellulose whisker composites were successfully prepared using a colloidal suspension of cellulose whiskers, to reinforce soy protein isolate (SPI) plastics. The cellulose whiskers, having an average length of 1.2 microm and diameter of 90 nm, respectively, were prepared from cotton linter pulp by hydrolyzing with sulfuric acid aqueous solution. The effects of the whisker content on the morphology and properties of the glycerol-plasticized SPI composites were investigated by scanning electron microscopy, dynamic mechanical thermal analysis, differential scanning calorimetry, ultraviolet-visible spectroscopy, water-resistivity testing and tensile testing. The results indicated that, with the addition of 0 to 30 wt.-% of cellulose whiskers, strong interactions occurred both between the whiskers and between the filler and the SPI matrix, reinforcing the composites and preserving their biodegradability. Both the tensile strength and Young's modulus of the SPI/cellulose whisker composites increased from 5.8 to 8.1 MPa and from 44.7 to 133.2 MPa, respectively, at a relative humidity of 43%, following an increase of the whisker content from 0 to 30 wt.-%. Furthermore, the incorporation of the cellulose whiskers into the SPI matrix led to an improvement in the water resistance for the SPI-based composites. 相似文献
2.
Mehdi Roohani Youssef Habibi Ghanbar Ebrahim Alain Dufresne 《European Polymer Journal》2008,44(8):2489-2498
Nanocomposite materials were prepared from copolymers of polyvinyl alcohol and polyvinyl acetate and a colloidal aqueous suspension of cellulose whiskers prepared from cotton linter. The degree of hydrolysis of the matrix was varied in order to vary the hydrophilic character of the polymer matrix and then the degree of interaction between the filler and the matrix. Nanocomposite films were conditioned at various moisture contents, and the dynamic mechanical and thermal properties were characterized using dynamic mechanical analysis and differential scanning calorimetry, respectively. Tensile tests were performed at room temperature to estimate mechanical properties of the films in the non linear range. All the results show that stronger filler/matrix interactions occur for fully hydrolyzed PVA compared to partially hydrolyzed samples. For moist samples, a water accumulation at the interface was evidenced. The reinforcing effect was found to be all the higher as the degree of hydrolysis of the matrix was high. 相似文献
3.
Thermal
properties of biocomposites 总被引:1,自引:0,他引:1
Ewa Rudnik 《Journal of Thermal Analysis and Calorimetry》2007,88(2):495-498
Thermal properties of new biocomposites prepared from modified starch
matrix reinforced with natural vegetable fibres were studied. DSC and TG methods
were applied to study thermal behaviour of biocomposites. Biocomposites were
obtained in the laboratory twin-screw extruder. Two kinds of natural fibres
were used, i.e. flax and cellulose in the amount of 0–40 mass%. DSC
curves of biocomposites reveal glass transition temperature, attributed to
the amorphous nature of the plasticized starch matrix. In general, incorporating
natural fibres into modified starch matrix leads to an increase in glass transition
temperature.
Thermal degradation of modified starch matrix and
cellulose reinforced biocomposites proceeds in three steps, whereas the degradation
process of flax reinforced biocomposites occurs in two steps. For unreinforced
matrix as well as for all biocomposites, regardless of type and amount of
reinforcement, the major mass loss is observed at the temperature above 300°C.
The increase in thermal stability with introduction of natural fibre is observed
for both flax and cellulose reinforced biocomposites. 相似文献
4.
Structure of cellulose and microcrystalline cellulose from various wood species, cotton and flax studied by X-ray scattering 总被引:2,自引:1,他引:1
Kirsi Leppänen Seppo Andersson Mika Torkkeli Matti Knaapila Nina Kotelnikova Ritva Serimaa 《Cellulose (London, England)》2009,16(6):999-1015
The structure of microcrystalline cellulose (MCC) made by mild acid hydrolysis from cotton linter, flax fibres and sulphite
or kraft cooked wood pulp was studied and compared with the structure of the starting materials. Crystallinities and the length
and the width of the cellulose crystallites were determined by wide-angle X-ray scattering and the packing and the cross-sectional
shape of the microfibrils were determined by small-angle X-ray scattering. The morphological differences were studied by scanning
electron microscopy. A model for the changes in microfibrillar structure between native materials, pulp and MCC samples was
proposed. The results indicated that from softwood or hardwood pulp, flax cellulose and cotton linter MCC with very similar
nanostructures were obtained with small changes in reaction conditions. The crystallinity of MCC samples was 54–65%. The width
and the length of the cellulose crystallites increased when MCC was made. For example, between cotton and cotton MCC the width
increased from 7.1 nm to 8.8 nm and the length increased from 17.7 nm to 30.4 nm. However, the longest crystallites were found
in native spruce wood (35–36 nm). 相似文献
5.
Ashish Guleria Raj K Rana 《International Journal of Polymer Analysis and Characterization》2017,22(7):595-609
In the present paper, starch-based biocomposites have been prepared by reinforcing corn starch matrix with mercerized Abelmoschus esculentus lignocellulosic fibers. The effect of fiber content on mechanical properties of composite was investigated and found that tensile strength, compressive strength, and flexural strength at optimum fiber content were 69.1%, 93.7% and 105.1% increased to that of cross-linked corn starch matrix, respectively. The corn starch matrix and its composites were characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric (TGA) analysis. The fiber reinforced composites were found to be highly thermal stable as compared to natural corn starch and cross-linked corn starch matrix. Further, water uptake and biodegradation studies of matrix and composites have also been studied. 相似文献
6.
T. Senthil Muthu Kumar A. Varada Rajulu Nadir Ayrilmis 《International Journal of Polymer Analysis and Characterization》2019,24(5):439-446
Biocomposites were fabricated using poly(propylene) carbonate as matrix and cellulosic polysaccharide banana (Musa acuminate) peel powder as filler in varying concentrations (5–25?wt.%) and were characterized for their functional properties. Microscopic analysis indicated the uniform distribution and existence of microfibrils in the filler. The thermal stability of the composites was lower than the matrix till 320?°C, beyond which it increased. The visco-elastic and mechanical behavior of the biocomposites was found to be enhanced with the addition of fillers. Thus, with better thermal, visco-elastic, and mechanical properties, the biocomposite films can be a replacement for the non-biodegradable polymers for packaging applications. 相似文献
7.
Smith Sundar Mohini Sain Kristiina Oksman 《Journal of Thermal Analysis and Calorimetry》2011,104(3):841-847
Thermal properties of polylactic acid (PLA) filled with Fe-modified cellulose long fibers (CLF) and microcrystalline cellulose
(MCC) were studied using thermo gravimetric analysis (TG), differential scanning calorimetry, and dynamic mechanical analysis
(DMA). The Fe-modified CLFs and MCCs were compared with unmodified samples to study the effect of modification with Fe on
electrical conductivity. Results from TG showed that the degradation temperature was higher for all composites when compared
to the pure PLA and that the PLA composites filled with unmodified celluloses resulted in the best thermal stability. No comparable
difference was found in glass transition temperature (T
g) and melting temperature (T
m) between pure PLA and Fe-modified and unmodified CLF- and MCC-based PLA biocomposites. DMA results showed that the storage
modulus in glassy state was increased for the biocomposites when compared to pure PLA. The results obtained from a femtostat
showed that electrical conductivity of Fe-modified CLF and MCC samples were higher than that of unmodified samples, thus indicating
that the prepared biocomposites have potential uses where conductive biopolymers are needed. These modified fibers can also
be tailored for fiber orientation in a matrix when subjected to a magnetic field. 相似文献
8.
Sandeep S. Laxmeshwar S. Viveka D. J. Madhu Kumar Dinesha R. F. Bhajanthri G. K. Nagaraja 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):639-647
In this work, cellulose was modified by using 2-(trifluromethyl)benzoylchloride by base catalyzed reaction. Modification of cellulose was confirmed by IR studies. The biodegradable composite films were developed by a film casting method using modified cellulose with poly(vinyl alcohol) and polypyrrolidone in different compositions. Film composites showed good biodegradability. Better barrier and mechanical properties showed by film composites as the percentage of modified cellulose increased. This indicates the importance of modified cellulose as a reinforcing agent. After analyzing these properties of film composites we came to the conclusion that, these biocomposites can be used for membrane and packaging applications. 相似文献
9.
Stefan Oprea Violeta Otilia Potolinca Petronela Gradinariu Aurora Joga Veronica Oprea 《Cellulose (London, England)》2016,23(4):2515-2526
Different contents of bonded cellulose were dispersed in a matrix of castor-oil-based polyurethane to produce composites with high susceptibility to fungal attack. We chose to bond the cellulose filler with free diisocyanate, to increase the crosslinking density. Measurements indicated physical and chemical interactions between the polyurethane matrix and cellulose filler. The cellulose network significantly enhanced the interfacial adhesion and thus improved the thermal stability and Young’s modulus of the composites. The influences of the amount of cellulose on the surface chemical structure, surface morphology, and mechanical properties after fungal attack were also investigated. The tensile strength and elongation at break of these composites substantially decreased after exposure to fungus. These composites with high content of renewable raw materials present an optimal balance of physical properties and biodegradability, with potential applications as ecofriendly biomaterials. 相似文献
10.
Karol Leluk Stanisaw Frckowiak Joanna Ludwiczak Tomasz Rydzkowski Vijay Kumar Thakur 《Molecules (Basel, Switzerland)》2021,26(1)
Recently, biocomposites have emerged as materials of great interest to the scientists and industry around the globe. Among various polymers, polylactic acid (PLA) is a popular matrix material with high potential for advanced applications. Various particulate materials and nanoparticles have been used as the filler in PLA based matrix. One of the extensively studied filler is cellulose. However, cellulose fibres, due to their hydrophilic nature, are difficult to blend with a hydrophobic polymer matrix. This leads to agglomeration and creates voids, reducing the mechanical strength of the resulting composite. Moreover, the role of the various forms of pure cellulose and its particle shape factors has not been analyzed in most of the current literature. Therefore, in this work, materials of various shapes and shape factors were selected as fillers for the production of polymer composites using Polylactic acid as a matrix to fill this knowledge gap. In particular, pure cellulose fibres (three types with different elongation coefficient) and two mineral nanocomponents: precipitated calcium carbonate and montmorillonite were used. The composites were prepared by a melt blending process using two different levels of fillers: 5% and 30%. Then, the analysis of their thermomechanical and physico-chemical properties was carried out. The obtained results were presented graphically and discussed in terms of their shape and degree of filling. 相似文献
11.
The meta kaolin (MK) clay particulate filler with different weight ratios viz., 0, 5, 10, 20 and 30 wt% were incorporated into castable polyurethane (PU)/polystyrene (PS) (90/10) interpenetrating polymer network (IPN). The effects of MK particulate filler loading on the mechanical and thermal properties of PU/PS (90/10) IPN composites have been studied. From the tensile behavior, it was noticed that a significant improvement in tensile strength and tensile modulus as an increase in MK filler content. Thermogravimetric analysis (TGA) data reveals the marginal improvement in thermal stability after incorporation of MK filler. TGA studies of the IPN composites have been performed in order to establish the thermal stability and their mode of thermal degradation. It was found that degradation of all composites takes place in two steps. Degradation kinetic parameters were obtained for the composites using three mathematical models. Tensile fractured composite specimens were used to analyze the morphology of the composites by scanning electron microscopic (SEM) technique. 相似文献
12.
Dong Cheng Xingye An Junhua Zhang Xiaofei Tian Zhibin He Yangbing Wen Yonghao Ni 《Cellulose (London, England)》2017,24(4):1631-1639
Regenerated cellulose (RC) film is an important cellulose-based product with a wide range of applications in the packaging industry and drug delivery. In this study, RC film was prepared using an organic electrolyte solution (OES)/ionic liquid (IL) system consisting of 1-ethyl-3-methylimidazolium acetate (EmimAc) and dimethyl sulfoxide (DMSO) to dissolve cotton linter at room temperature. Results showed that OES with EmimAc molar fraction in the range from 0.2 to 0.4 could rapidly dissolve cotton linter at room temperature, in contrast to 80 °C for EmimAc solution (control). The cellulose degradation was therefore much less than for the control, resulting in significant improvement in the mechanical properties and thermal stability of the RC film. In addition, the presence of DMSO significantly decreased the viscosity of the cellulose/OES system, being advantageous for casting of the RC film. 相似文献
13.
Han-Seung Yang Douglas J. Gardner Jacques W. Nader 《Journal of Thermal Analysis and Calorimetry》2011,103(3):1007-1015
Microcrystalline cellulose-filled polypropylene (PP) composites and cellulose nanofiber-filled composites were prepared by
melt blending. The compounded material was used to evaluate dispersion of cellulose fillers in the polypropylene matrix. Thermogravimetric
analysis (TG) and mechanical testing were conducted on composites blended multiple times and the results were compared with
single batch melt blended composites. The residual mass, tensile strength, and coefficient of variance values were used to
evaluate dispersion of the microcrystalline cellulose fillers in the PP matrix. The potential of using TG to evaluate cellulose
nanofiber-filled thermoplastic polymers was also investigated and it was found that the value and variability of residual
mass after TG measurements can be a criterion for describing filler dispersion. A probabilistic approach is presented to evaluate
the residual mass and tensile strength distribution, and the correlation between those two properties. Both the multiple melt
blending and single batch composites manufactured with increased blending times showed improved filler dispersion in terms
of variation and reliability of mechanical properties. The relationship between cellulose nanofiber loading and residual mass
was in good agreement with the rule of mixtures. In this article, the authors propose to use a novel method for dispersion
evaluation of natural fillers in a polymer matrix using TG residual mass analysis. This method can be used along with other
techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD)
for filler dispersion evaluation in thermoplastic composites. 相似文献
14.
Guangmei Xia V. Sadanand B. Ashok K. Obi Reddy Jun Zhang 《International Journal of Polymer Analysis and Characterization》2015,20(8):693-703
The aim of the present work was to utilize waste leather buff (WLB) as filler in cellulose and make biocomposites for packaging applications such as wrappers. Cellulose was dissolved in the environmentally friendly ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). To this solution, WLB was added in amounts of 5 to 25 wt.% of cellulose. The cellulose and cellulose/WLB composite films were prepared by regenerating the corresponding cast solutions in a water coagulation bath followed by washing and drying. These films were tested for their tensile properties, thermal stability, and morphology. The tensile modulus and strength of the composite films were lower than those of the matrix. The lowering of the tensile modulus and strength with increasing WLB loading was attributed to the random orientation of the leather fibers of WLB in the composites. However, the % elongation at break of the composite films was found to be higher than that of the matrix and increased with increasing WLB content. The possible interaction between the matrix and WLB filler was probed using FT-IR analysis. The thermal stability of the composite films was higher than that of the matrix. The increase in thermal stability of the composite films was attributed to cross-linked collagen protein leather fibers in WLB. The fractographs of the composite films indicated good interfacial bonding between cellulose and leather fibers of WLB. These composite films may be considered for packaging and wrapping applications. 相似文献
15.
Yude Zhang Qian Zhang Qinfu Liu Hongfei Cheng Ray L. Frost 《Journal of Thermal Analysis and Calorimetry》2014,115(2):1013-1020
Styrene butadiene rubber (SBR) composites filled with fillers, such as modified kaolinite (MK), precipitated silica (PS), and the hybrid fillers containing MK and PS, were prepared by melt blending. The kaolinite sheets were finely dispersed in the SBR matrix around 20–80 nm in thickness and reached the nano-scale. The SBR composites with fillers exhibited excellent thermal stability compared to the pure SBR. The thermal stability of SBR composites was improved with the increasing of MK mass fraction. When MK hybridized with PS, kaolinite sheets were covered by the fine silica particles and the interface between filler particles and rubber matrix became more indistinct. SBR composite filled by hybrid fillers containing 40 phr MK and 10 phr PS became more difficult in decomposition and was better than that of 50 phr PS/SBR and 50 phr MK/SBR in thermal stability. Therefore, the hybridization of the fine silica particles with the kaolinite particles can effectively improve the thermal stability of SBR composites. 相似文献
16.
I. P. Dobrovol’skaya V. E. Yudin N. F. Drozdova V. E. Smirnova I. V. Gofman E. N. Popova A. M. Bochek N. M. Zabivalova I. V. Plugar’ E. F. Panarin 《Polymer Science Series A》2011,53(2):166-171
The structure of film composites based on methyl cellulose and fillers, such as montmorillonite and silver nanoparticles stabilized
by poly(vinylpyrrolidone) (Poviargol), is studied by X-ray diffraction. In the composite, montmorillonite nanoparticles exist
in the exfoliated state; when the content of the nanoparticles is below 7 wt %, the crystallinity of methyl cellulose increases.
Owing to the presence of the filler and structural ordering of the matrix, elastic characteristics improve and the degradation
temperature of the composites increases. The X-ray structural data show that the Ag particles in the methyl cellulose-Poviargol
composite are 30 nm in size. The introduction of up to 20 wt % Poviargol assists the crystallization of methyl cellulose.
The strength and strain characteristics of the film composites based on methyl cellulose and Poviargol make it possible to
use these composites in medicine and agriculture. 相似文献
17.
Microfibrillated cellulose (MFC), which consists of a web‐like array of cellulose fibrils having a diameter in the range of 10–100 nm, was incorporated into a cellulose acetate (CA) matrix to form a totally biobased structural composite. Untreated and a 3‐aminopropyltriethoxysilane (APS) surface treated MFC was combined with a CA matrix by film casting from an acetone suspension. The effectiveness of the surface treatment was determined by infrared spectroscopy and X‐ray photoelectron spectroscopy. The Young's moduli of APS treated MFC composite films increase with increasing MFC content from 1.9 GPa for the CA to 4.1 GPa at 7.5 wt % of MFC, which is more than doubled. The tensile strength of the composite film increases to a maximum of 63.5 MPa at 2.5 wt % compared to the CA which has a value of 38 MPa. The thermal stability of composites with treated MFC is also better than the untreated MFC. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 153–161, 2010 相似文献
18.
Bio‐based nanocomposite films were successfully developed using cellulose whiskers as the reinforcing phase and chitosan as the matrix. Cellulose whiskers, with the lengths of 400 ± 92 nm and diameters of 24 ± 7.5 nm on average, were prepared by hydrolyzing cotton linter with sulfuric acid solution. The effects of whisker content on the structure, morphology and properties of the nanocomposite films were characterized by SEM, XRD, FTIR, UV‐vis spectroscopy, DMA, TG, tensile testing, and swelling experiment. The results indicated that the nanocomposites exhibited good miscibility, and strong interactions occurred between the whiskers and the matrix. With increasing whisker content from 0 to 15–20 wt %, the tensile strength of the composite films in dry and wet states increased from 85 to 120 MPa and 9.9 to 17.3 MPa, respectively. Furthermore, the nanocomposite films displayed excellent thermal stability and water resistance with the incorporation of cellulose whiskers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1069–1077, 2009 相似文献
19.
Seawater ageing of flax/poly(lactic acid) biocomposites 总被引:1,自引:0,他引:1
Natural fibre reinforced biopolymer composites, or biocomposites, are an alternative to the glass fibre reinforced thermoset composites widely used today in marine applications. Biocomposites offer good mechanical properties and total biodegradability, but if they are to be adopted for marine structures their durability in a seawater environment must be demonstrated. In the present study unreinforced PLLA (Poly(l-Lactic acid)), injected and film stacked flax composites with the same PLLA matrix have been examined. All the samples were aged in natural seawater at different temperatures in order to accelerate hygrothermal ageing. Changes to physico-chemical and mechanical behaviour have been followed by weight measurements, thermal and gel permeation chromatography (GPC) analyses, and tensile testing, completed by acoustic emission recording and scanning electron microscopy (SEM) examination. The matrix tensile stiffness is hardly affected by seawater at temperatures to 40 °C but the composite loses stiffness and strength. Fibre/matrix interface weakening is the main damage mechanism induced by wet ageing, but both matrix and fibre cracks also appear at longer periods. 相似文献
20.
Environmentally friendly biocomposites were prepared by blending wheat gluten(WG)as a matrix, hydroxyethyl cellulose(HEC)as a filler,and glycerol as a plasticizer,followed by thermo-molding of the mixture at 120°C for crosslinking the matrix.Moisture absorption,tensile properties,dynamic mechanical analysis,and dynamic rheology were evaluated in relation to the glycerol content.Tensile strength and modulus drop dramatically with increasing glycerol content,which is accompanied by significant depression in the glass transition temperature and improvement in the extensibility of the biocomposites. 相似文献