Study on thermal and mechanical properties of cis- and trans-polyisoprene blends implanted by carbon ions (original) (raw)
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Analysis of cellulose based nanocomposites & potential applications
Materials Today: Proceedings, 2021
Cellulose based nanocomposites have achieved a lot more attraction in recent years owing to its renewability, good mechanical strength and durability. The cellulose based nanocomposite development process typically involves extraction of cellulose from source materials such as wood, agricultural residue etc., isolation of nanocellulose from the cellulose and reinforcement of nanocellulose in polymers. This review outlines the various chemo-mechanical methods used for extraction of cellulose and for isolation nanocellulose. Also, the different methods used for fabrication of cellulose nanocomposites are discussed in details. Finally, the potential applications of nanocellulose composites different industries such as food and packaging, structural, bio- medical and electronics are also presented.
This article addresses the effect of nanocrystalline cellulose (NCC) on the mechanical and thermal properties of polypropylene (PP). A new approach was adopted to produce mechanically improved and thermally stable PP-NCC nanocomposite. This approach involved producing optimized PP-NCC nanocomposite by adding NCC nanoparticles to PP matrix at different concentrations by means of injection molding process. The aim of this work was to find the optimum NCC concentration to enhance the mechanical and thermal properties of the PP matrix. The mechanical and thermal behavior of PP-NCC nanocomposite was studied by performing three-point bend, nanoindentation, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Fourier transform infrared (FTIR) spectroscopy tests. The results showed that the mechanical properties of strength, modulus, and hardness of the nanocomposites increased with the addition of NCC by 6.5%, 19%, and 150%, respectively. DSC results showed that the addition of NCC to PP does not affect the thermal stability (melting temperature). However, TGA showed that upon inclusion of NCC nanoparticles, the thermal stability of the samples improved compared to pure PP except for the 5% added NCC. This is attributed to the presence of NCC rod-like particles that dissipated heat by generating tortuous paths, as depicted in the SEM results and verified by FTIR results.
Polymer Journal, 2011
A bio-based fibrous film intended to be used as a food-packaging component was electrospun from blend solutions of cellulose acetate (CA) in neat acetic acid and poly(ethylene oxide) (PEO) in 90% ethanol. The CA/PEO blend ratios were varied to determine the effects of PEO on the morphology, moisture-adsorption and tensile properties of the blended fibrous films. Zinc oxide nanoparticles (ZnO NPs) incorporated (2-20 wt% of PEO) into the blended fibers were tested for their effect on tensile and thermal properties of the nanocomposite films. The results indicated that the addition of PEO at 9 wt% improved tensile strength, elongation and elasticity (Po0.05) of the CA-based fibrous films. The energy-dispersive spectrometer-scanning electron microscopy results suggested that zinc elements were well dispersed in the CA-PEO-blend fiber matrix. The addition of ZnO NPs at 20 wt% of PEO led to a significant improvement in the elongation and tensile strength of the CA-PEO-blend fibrous film (Po0.05). This improvement was attributed to the association between ZnO NPs and the semi-crystalline structures of the PEO, as evidenced by differential scanning calorimetry thermograms and X-ray diffraction spectra.
Effect of organoclay content and molecular weight on cellulose acetate nanocomposites properties
Polymer Degradation and Stability, 2012
Nanocomposites based on cellulose acetate (CA), a commercial organoclay (Cloisite30B) and triethyl citrate (TEC) were obtained using a solution casting method. Different nanocomposites were prepared according to different organoclay contents (2.5, 5.0, 7.5 and 10.0 wt.%) and molecular weight of cellulose acetate (Mn 30,000 and 50,000). The properties of the nanocomposites were evaluated by means of opacity index, X-ray diffraction (XRD), differential scanning calorimetry (DSC), mechanical (modulus of elasticity, tensile strength and elongation at break), scanning electron microscopy (SEM) and oxygen transmission rate (OTR) measurements. All obtained nanocomposites showed the intercalation of polymer inside the clay structure which was slightly favored for nanocomposites with CA 30,000. Important changes on the opacity index, mechanical properties, glass transition and melting temperatures, crystalline fraction, oxygen permeability and fracture morphology of nanocomposite films were observed according to the increase of organoclay content. On the other hand, intercalation level and oxygen permeability showed some differences with the molecular weight of cellulose acetate.
Nanofibrillated cellulose/nano SiO2/poly(vinyl alcohol) composite films: Evaluation of properties
BioResources, 2021
Effects of nanofibrillated cellulose (NFC) and nano-silicon dioxide on dynamic mechanical thermal analysis and physical properties of nanocomposites films made of poly (vinyl alcohol) (PVOH) were investigated. For this purpose, the nanoparticles were mixed with PVOH at 0%, 5%, and 10% weight. Water absorption, dynamic mechanical thermal, transparency, and wettability properties were evaluated according to corresponding standard test methods. The morphology of nanocomposites was explored by using a field emission scanning electron microscope technique. The films became increasingly opaque with increasing nanoparticles contents, although the composites also retained moderate transparency. According to the results of the tests, the dynamic mechanical thermal (DMTA) properties of PVOH composite films were significantly improved with the increase of NFC and silica nanoparticles loading. The samples containing 20 wt% of nano-SiO2 exhibited higher hydrophobicity compared with that of 20 wt...
Morphological and Thermal Properties of Cellulose Nanofibrils Reinforced Epoxy Nanocomposites
Drvna industrija, 2015
Epoxy resins have gained attention as important adhesives because they are structurally stable, inert to most chemicals, and highly resistant to oxidation. Different particles can be added to adhesives to improve their properties. In this study, cellulose nanofi brils (CNFs), which have superior mechanical properties, were used as the reinforcing agent. Cellulose nanofi brils were added to epoxy in quantities of 1 %, 2 % and 3 % by weight to prepare nanocomposites. Morphological characterization of the composites was done with scanning electron microscopy (SEM). Thermal properties of the nanocomposites were investigated with Thermogravimetric Analyzer (TGA/DTG) and Differential Scanning Calorimeter (DSC). SEM images showed that the cellulose nanofi brils were dispersed partially homogenous throughout the epoxy matrix for 1 % CNF. However, it was observed that the cellulose nanofi brils were aggregated (especially for 2 and 3 % CNFs) in some parts of the SEM images, and the ratios of the aggregated parts increased as the loading rate of the cellulose nanofi brils increased. The TGA curve showed that DTG and decomposition temperature of pure epoxy was higher than that of the nanocomposites. The DSC curve showed that the glass transition temperature (T g ) value of pure epoxy was found to be similar with Tg of the nanocomposites.
Kenaf cellulose whiskers reinforced nanocomposites manufactured by solution casting. Different kenaf cellulose whiskers percentage was used as reinforcement into cellulose acetate butyrate (CAB) matrix. The percentages of reinforcement used in this study are 2.5, 5, 7.5, and 10%. Resulted nanocomposite characterized by fourier transforms infrared (FT-IR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). FTIR analysis showed no intermolecular hydrogen bonding between CAB and whiskers. Thermal analysis found that whiskers reinforcement did not affect the decomposition temperature of nanocomposite. However, single decomposition temperature indicated well miscibility of nanocomposite. DSC curves revealed that melting temperature and CAB recrystallization did not show any changes during heat-cool-heat measurement. In addition, glass transition was unchanged as kenaf whiskers content increased. It indicated that kenaf cellu...
PREPARATION AND CHARACTERIZATION OF NANOFIBRILLATED CELLULOSE/POLY (VINYL ALCOHOL) COMPOSITE FILMS
Poly (vinyl alcohol) based composite films with different loadings of cellulose nanofibrils were prepared using a solvent casting method and their tensile, optical and wettability properties were tested. The morphology of both neat poly (vinyl alcohol) and nanocomposites was explored by using a field emission scanning electron microscope technique. Results indicated that the tensile strength and Young's modulus of poly (vinyl alcohol) composite films were significantly improved with the increase of cellulose nanofibrils loading. However, the percentage of elongation at break decreased with increasing of cellulose nanofibrils. The films became increasingly opaque with increasing cellulose nanofibrils contents, although the composites also retained moderate transparency. The samples containing cellulose nanofibrils exhibited higher hydrophobicity compared with that of neat poly (vinyl alcohol). Field emission scanning electron microscope micrographs revealed that the cellulose nanofibrils were homogeneously dispersed in the poly (vinyl alcohol) matrix.
This research was aimed to use ball milling method to extract cellulose nanofibers (CNFs) from a bio-waste (i.e. wheat straw), and also to use the extracted cellulose nanofibers as reinforcing materials in polyvinyl alcohol (PVA) thin film. To study the effect of cellulose nanofibers (CNFs) on mechanical and thermal properties of polyvinyl alcohol (PVA) nano-composite films, thin film nano-composites were loaded with different loading of cellulose nanofibers (CNFs) by weight percent (i.e. 1,3,5 and 7% loading). As a result of the research, we found that the tensile and thermal properties of PVA thin composite increased up to 5% loading of cellulose nanofibers (CNFs). In contrast, the tensile as well as thermal properties of PVA nano -composite film degraded because of poor dispersion and agglomeration of CNFs