“…This might be due to the poor dispersion of cellulose nanofillers into the polymer matrix and formation of larger agglomerates. 19,24 Figure 10.Tensile testing results of PMMA, in situ PMMA/cellulose nanocomposite (IPC) and ex situ PMMA/cellulose nanocomposite (EPC) films: (a) tensile strength graph and (b) Young’s modulus graph.…”
Section: Resultsmentioning
confidence: 99%
“…From Figure 5(a), it is seen that CNPs were homogeneously dispersed within the polymer matrix and a network structure was formed. 19 Some partially dissolved granules were seen in Figure 5(a). But no such network was formed in case of EPC.…”
Section: Tem Analysismentioning
confidence: 98%
“…This might be due to the poor dispersion of cellulose nanofillers into the polymer matrix and formation of larger agglomerates. 19,24…”
Polymethylmethacrylate/cellulose nanocomposites were prepared by in situ polymerization and ex situ dispersion techniques with 10 wt% loading of cellulose nanoparticles. Cellulose nanoparticles were prepared from jute fibers by acid hydrolysis. The suspension polymerization of methylmethacrylate was carried out in presence of cellulose nanoparticles, which were dispersed in water medium and in situ polymethylmethacrylate/cellulose nanocomposite granules were formed. These granules were dissolved in chloroform, sonicated and films were prepared by solution casting method (IPC). Polymethylmethacrylate granules were prepared by similar suspension polymerization process and made into films by solution casting method. Another set of polymethylmethacrylate/cellulose nanocomposite films were prepared by dispersing nanocellulose powder (10 wt%) in polymethylmethacrylate solution and casting into films (EPC). The unreinforced polymethylmethacrylate and polymethylmethacrylate extracted from IPC films were subjected to size exclusion chromatography and nuclear magnetic resonance study. The average molecular weights of neat polymethylmethacrylate and polymethylmethacrylate from IPC were quite close, but the ‘dispersity’ was slightly higher in IPC than that in neat polymethylmethacrylate. Fourier transform infrared spectroscopy revealed some shifts in EPC. X-ray diffraction study showed a similar nature of X-ray diffraction curves in all the samples. Transmission electron microscopy of IPC and EPC showed a better dispersion of fillers and formation of a network structure in IPC, whereas in EPC, the fillers were agglomerated. Surface morphology of the films was examined by field emission scanning electron microscopy and atomic force microscopy. IPC exhibited a much smoother surface compared to that of EPC indicating a more homogeneous dispersion of fillers. IPC showed a higher modulus of elasticity compared to PMMA and EPC. Differential scanning calorimetry showed a shift of glass transition temperature to a higher one (125°C) in IPC compared to that of polymethylmethacrylate (118°C). Thermogravimetric analysis was done to study the thermal degradation behavior of the composites.
“…This might be due to the poor dispersion of cellulose nanofillers into the polymer matrix and formation of larger agglomerates. 19,24 Figure 10.Tensile testing results of PMMA, in situ PMMA/cellulose nanocomposite (IPC) and ex situ PMMA/cellulose nanocomposite (EPC) films: (a) tensile strength graph and (b) Young’s modulus graph.…”
Section: Resultsmentioning
confidence: 99%
“…From Figure 5(a), it is seen that CNPs were homogeneously dispersed within the polymer matrix and a network structure was formed. 19 Some partially dissolved granules were seen in Figure 5(a). But no such network was formed in case of EPC.…”
Section: Tem Analysismentioning
confidence: 98%
“…This might be due to the poor dispersion of cellulose nanofillers into the polymer matrix and formation of larger agglomerates. 19,24…”
Polymethylmethacrylate/cellulose nanocomposites were prepared by in situ polymerization and ex situ dispersion techniques with 10 wt% loading of cellulose nanoparticles. Cellulose nanoparticles were prepared from jute fibers by acid hydrolysis. The suspension polymerization of methylmethacrylate was carried out in presence of cellulose nanoparticles, which were dispersed in water medium and in situ polymethylmethacrylate/cellulose nanocomposite granules were formed. These granules were dissolved in chloroform, sonicated and films were prepared by solution casting method (IPC). Polymethylmethacrylate granules were prepared by similar suspension polymerization process and made into films by solution casting method. Another set of polymethylmethacrylate/cellulose nanocomposite films were prepared by dispersing nanocellulose powder (10 wt%) in polymethylmethacrylate solution and casting into films (EPC). The unreinforced polymethylmethacrylate and polymethylmethacrylate extracted from IPC films were subjected to size exclusion chromatography and nuclear magnetic resonance study. The average molecular weights of neat polymethylmethacrylate and polymethylmethacrylate from IPC were quite close, but the ‘dispersity’ was slightly higher in IPC than that in neat polymethylmethacrylate. Fourier transform infrared spectroscopy revealed some shifts in EPC. X-ray diffraction study showed a similar nature of X-ray diffraction curves in all the samples. Transmission electron microscopy of IPC and EPC showed a better dispersion of fillers and formation of a network structure in IPC, whereas in EPC, the fillers were agglomerated. Surface morphology of the films was examined by field emission scanning electron microscopy and atomic force microscopy. IPC exhibited a much smoother surface compared to that of EPC indicating a more homogeneous dispersion of fillers. IPC showed a higher modulus of elasticity compared to PMMA and EPC. Differential scanning calorimetry showed a shift of glass transition temperature to a higher one (125°C) in IPC compared to that of polymethylmethacrylate (118°C). Thermogravimetric analysis was done to study the thermal degradation behavior of the composites.
“…The sample was stained with uranyl acetate (around 5 wt%) for 3 min (Zimmermann et al 2006). TEM graphs were acquired with Philips CM-12 at 60 kV (Philips, Eindhoven, The Netherlands).…”
Section: Transmission Electron Microscopy (Tem) Graphsmentioning
Nanocrystalline cellulose (NCC) was prepared by sulfuric acid hydrolysis of microcrystalline cellulose. A differential centrifugation technique was studied to obtain NCC whiskers with a narrow size distribution. It was shown that the volume of NCC in different fractions had an inverse relationship with relative centrifugal force (RCF). The length of NCC whiskers was also fractionized by differential RCF. The aspect ratio of NCC in different fractions had a relatively narrow range. This technique provides an easy way of producing NCC whiskers with a narrow size distribution.
“…1 In view of this exceptional property, their high aspect ratio and their large specific surface area, cellulose nanofibres have significant potential for the preparation of polymer composites. To this end, it has previously been established that cellulose nanofibres can give significant reinforcing effects in a range of polymers, including polyvinyl alcohol, [2][3][4] polylactic acid, 5 cellulose acetate butyrate, 6 hydroxypropyl cellulose, 7 starch 8 and polysulfone. 9 However, there are currently particular difficulties associated with effectively dispersing these nanoreinforcements into thermoplastics by melt mixing, due to their tendency to reagglomerate and their inherent thermal instability.…”
A procedure is described for preparing polyamide-6 (PA-6) reinforced with cellulose nanofibres. The cellulose nanofibres were obtained from flax and microcrystalline cellulose (MCC) using combinations of acid hydrolysis, ball milling and ultrasound, then characterised by transmission electron microscopy (TEM) in order to determine their size and geometry. The nanofibres produced from the different feedstock sources were of a similar order with lengths ranging from 21 to 300 nm and diameters between 2 and 22 nm. PA-6 nanocomposite films were subsequently prepared from these nanofibres using a solution casting technique. Their chemical and physical structure was analysed using Fourier transform infrared analysis (FTIR) and TEM. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were also applied to compare their thermal properties with unfilled polymer. Dynamic mechanical thermal analysis and tensile measurements demonstrated a significant enhancement in mechanical properties was possible with a low addition of cellulose nanofibres to the polymer matrix.
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