Mechanical Properties Of Chitosan Research Articles

Surface decoration of graphene oxide with tragacanth gum as a promising way to improve the mechanical properties of chitosan nanocomposite; experimental, micromechanical, and simulation study

The interfacial interaction of graphene oxide (GO) with the host polymer is of particular importance in the development of new nanocomposites with ultimate performance. In this perspective, the influence of functionalized GO with the tragacanth gum (TG) polysaccharide on the mechanical characteristic of chitosan (CS) biopolymer was investigated. Spectroscopic and microscopic analysis thoroughly confirmed the TG functionalization process of GO (TG-GO). The understanding of the reinforcement behavior of TG-GO in the host polymer (CS) was constructed by combination of tensile, micro-mechanical/structural testing, as well as molecular dynamic simulation of interfacial interaction. Our finding represented that this functionalization put a remarkable impact on the mechanical properties of CS, which is evident on the microstructure of the fracture surface. The Halpin-Tsai model verified the observed increasing trend in mechanical performance. Simulation results revealed that TG-GO has better interfacial interaction with CS, which is highly in good agreement with the boosted mechanical performance.

Chitosan-Sodium Caseinate Composite Edible Film Incorporated with Probiotic Limosilactobacillus fermentum: Physical Properties, Viability, and Antibacterial Properties.

Single-use synthetic plastics that are used as food packaging is one of the major contributors to environmental pollution. Hence, this study aimed to develop a biodegradable edible film incorporated with Limosilactobacillus fermentum. Investigation of the physical and mechanical properties of chitosan (CS), sodium caseinate (NaCas), and chitosan/sodium caseinate (CS/NaCas) composite films allowed us to determine that CS/NaCas composite films displayed higher opacity (7.40 A/mm), lower water solubility (27.6%), and higher Young's modulus (0.27 MPa) compared with pure CS and NaCas films. Therefore, Lb. fermentum bacteria were only incorporated in CS/NaCas composite films. Comparison of the physical and mechanical properties of CS/NaCas composite films incorporated with bacteria with those of control CS/NaCas composite films allowed us to observe that they were not affected by the addition of probiotics, except for the flexibility of films, which was improved. The Lb. fermentum incorporated composite films had a 0.11 mm thickness, 17.9% moisture content, 30.8% water solubility, 8.69 A/mm opacity, 25 MPa tensile strength, and 88.80% elongation at break. The viability of Lb. fermentum after drying the films and the antibacterial properties of films against Escherichia coli O157:H7 and Staphylococcus aureus ATCC 29213 were also evaluated after the addition of Lb. fermentum in the composite films. Dried Lb. fermentum composite films with 6.65 log10 CFU/g showed an inhibitory effect against E. coli and S. aureus (0.67 mm and 0.80 mm inhibition zone diameters, respectively). This shows that the Lb.-fermentum-incorporated CS/NaCas composite film is a potential bioactive packaging material for perishable food product preservation.

The effect of nanocellulose on mechanical and physical properties of chitosan-based biocomposites

The effect of two types of nanocellulose on the mechanical properties of chitosan (CH) film was examined in terms of elongation, tensile strength, and dynamic-mechanical properties such as tan δ and storage modulus. Chitosan films were reinforced by cellulose nanocrystal (CNC) and cellulose nanofiber (CNF) with different ratios. CH/CNC and CH/CNF nanocomposite films containing 0–7 wt.% nanofibers were produced by solution casting. A comparison between CNC and CNF was made based on their nanostructures and interfacial bonding with the CH matrix. For both CNC and CNF, reinforcing effects in nanocomposite polymer films were presented. The results demonstrated that nanocomposite films can increase mechanical properties; 7 wt.% CNF and CNC had the most increasing effect on the mechanical properties, raising the tensile strength of the chitosan film by 104% and 52%, respectively. Moreover, the values of CH/CNC and CH/CNF films showed higher storage modulus compared to the pure chitosan film. CNF shows higher modulus and strength compared with CNC at the same amount of fiber because of CNFs’ percolation networks and their larger aspect ratio. Morphological studies revealed the dispersion of CNC and CNF is in the contiguous matrix of chitosan with a homogeneous distribution without agglomeration. The results also illustrated that CNC and CNF can improve the water resistance of chitosan films. The mechanical properties of composite films were acceptable to use as artificial skin and wound dressings.

3D printed artificial cornea for corneal stromal transplantation

The aim of this study is to understand the optical, biocompatible, and mechanical properties of chitosan (CS) and polyvinyl-alcohol (PVA) based corneal stroma constructs using 3D printing process. Corneal stroma is tested for biocompatibility with human adipose tissue-derived mesenchymal stem cells (hASCs). Physico-chemical and chemical characterization of the construct was performed using scanning electron microscopy (SEM), fourier transforms infrared spectroscopy (FTIR). Optical transmittance was analyzed using UV-Spectrophotometer. Results showed fabricated constructs have required shape and size. SEM images showed construct has thickness of 400 µm. The FTIR spectra demonstrated the presence of various predicted peaks. The swelling and degradation studies of 13%(wt)PVA and 13%(wt)PVA/(1, 3, 5)%(wt)CS showed to have high swelling ratios of 7 days and degradation times of 30 days, respectively. The light transmittance values of the fabricated cornea constructs decreased with CS addition slightly. Tensile strength values decreased with increasing CS ratio, but we found to support intraocular pressure (IOP) which ranges from 12 to 22 mm-Hg. Preliminary biostability studies showed that composite constructs were compatible with hASCs even after 30 days’ of degradation, showing potential for these cells to be differentiated to stroma layer in future. This study has implications for the rapid and custom fabrication of various cornea constructs for clinical applications.

Sorption, diffusivity, permeability and mechanical properties of chitosan, potassium sorbate, or nisin incorporated active polymer films.

The active multilayer packaging films were formed from low-density polyethylene (LDPE) and polyamide containing a 2% antimicrobial agent in one of the LDPE sides of the film (LDPE/polyamide/LDPE-2% antimicrobial agent). The antimicrobial agents used were potassium sorbate (PS-film), nisin (N-film), or chitosan (CTS-film). The effects of antimicrobial incorporation on water vapor permeability (P), diffusivity (D eff ), and solubility (S o and S H ) of the active and control films (LDPE/polyamide/LDPE) were investigated. A dynamic vapor sorption analyzer (DVS) was used to estimate the sorption isotherms of the films at 25°C. Peleg was found to be the best equation to describe sorption behaviors. The addition of PS and nisin into the film matrix resulted in a lower P than that of the control film. The D eff values of the active films were lower than those of control films, except for the CTS-film. The high water-holding capacity of PS and nisin might limit the D eff of the respective films. It was found that Henry's law was applicable to relate P, D eff , and S o and S H values of the multilayer film [correlation coefficient (r) = 0.909-0.971]. The mechanical and thermal properties of the active films were not significantly affected by the incorporation of PS and nisin (p > 0.05). However, the impact of stress and elongation (transverse direction) on the CTS-film was lower than on other films, which indicated that chitosan improved the mechanical properties of the film.

Study the effect of TiO2 nanoparticles on Physical properties of Biopolymer blend

Chitosan (CH) / Poly (1-vinylpyrrolidone-co-vinyl acetate) (PVP-co-VAc) (7:3) blend [CH/(PVP-co-VAc)] reinforced with two types of nanoparticle of titanium oxide TiO2 (type I & II) were prepared by solution casting method. The nanocomposites prepared with different concentrations (1, 2, 3.5, 5, 7.5, and 10) wt%. The tests carried out were AFM, FTIR, Tensile strength, Thermal conductivity measurement, and Weight gain. The results of the AFM test showed that the roughness of the surface decreased with the addition of a small amount of nanoparticles (1 wt.%) to the CH/(PVP-co-VAc) blend. FTIR results for blend film indicates a significant degree of composition between (PVP-co-VAc) and CH molecules. Nanocomposite films indicate that the composition among polymer blends and Nano are associated with changes in intensity, shape, and position of modes. The mechanical properties of chitosan were enhanced by the addition of TiO2 nanoparticle with significant increases in tensile strength (from 47.87 MPa to 64.95 ~ 70 MPa). Because interfacial bonding and homogenous distribution between the nanoparticles and the blend were supportive of markedly improved mechanical strength. The results of thermal conductivity and water absorption showed that the highest values were achieved in the polymer blend (CH/[PVP-co-VAc]), whereas its decrease with the increase of the nanoparticle incorporation.

The effect of the crosslinking agent on physical and mechanical properties of Chitosan / Banana flour sheet

The effect of the crosslinking agent on physical and mechanical properties of Chitosan / Banana flour sheet

The effect of fullerene soot on the mechanical properties of chitosan

The effect of fullerene soot on the mechanical properties of chitosan

Preparation of Chitosan/Collagen Blend Membranes for Wound Dressing: A Study on FTIR Spectroscopy and Mechanical Properties

The effect of different gamma-ray irradiations on the functional groups and the mechanical properties of chitosan, collagen, and chitosan/collagen blend have been studied. Commercially available chitosan and extract of collagen from bovine tendon by acid dissolution method were employed. Chitosan, collagen and chitosan/collagen blend membranes were prepared using the solvent evaporation method. The dried membranes were subjected to gamma-ray irradiation using 0, 15, and 25 kGy. The membranes then characterized by Infrared spectroscopy and measured in tensile and elongation at break. The irradiated chitosan membranes displayed reduced intensity of -OH, -CH, -NH and -C-O-C groups, whereas, the collagen membranes revealed amide I, II and III groups. The irradiated chitosan/collagen (50/50%) blend membranes demonstrated the decreased intensities in the –OH and amide groups. The application of gamma-ray irradiation had produced chitosan/collagen blend membranes with a tensile strength and elongation at break between the chitosan and collagen membranes. It was further determined that the decrease in the mechanical properties of the membranes was likely to be due to some changes of the functional groups.

The properties of chitosan and gelatin films incorporated with ethanolic red grape seed extract and Ziziphora clinopodioides essential oil as biodegradable materials for active food packaging

The aim of this study was to improve different characteristics including antibacterial, antioxidant, physical and mechanical properties of chitosan (Ch) and gelatin (Ge) films by incorporating Ziziphora clinopodioides essential oil (ZEO; 0 and 1% v/w) and ethanolic grape seed extract (GSE; 0 and 1% v/w). The main compounds of the ZEO were carvacrol (65.22%) and thymol (19.51%). According to our findings, addition of aforementioned materials could improve total phenolic content, antibacterial and antioxidant activities, thickness and also water vapor barrier property. ZEO and GSE reduces swelling index, tensile strength, puncture force and puncture deformation of Ch and Ge films. Pure Ch and Ge films had slightly yellow and white appearances, respectively, while films incorporated with GSE in combination with ZEO had grey appearances. This study indicated the some benefits of addition of ZEO and GSE into Ch and Ge films and their potentials for application as biodegradable active packaging.

Physical characteristics of chitosan-silica composite of rice husk ash

Some previous studies showed that the characteristics of chitosan membranes have a very rigid and non-porous structure so that its utilization is not maximized, particularly in the filtration process. Hence, it needs modification to improve the quality of the chitosan membranes. Adding the silica into the chitosan membranes is one of the offered solutions to overcome the problems of physical and mechanical properties of chitosan. This study aims to investigate the effect of variations in the silica composition to the physical characteristics of the chitosan-silica membranes of rice husk ash that were synthesized. The chitosan used is derived from the chitin of Vannamei shrimps’ shell with 82% degree of de-acetylation, while the silica was synthesized from rice husk ash with rendering of silica (SiO2) by 5% and the results of XRD analysis showed an amorphous phase. Membrane synthesis was performed using the phase inversion method with chitosan-silica mass ratios of rice husk ash, which were 1:0.0; 1:0.5; 1:1.0; 1:1.5 and 1:2.0. The results showed that the addition of silica increases the swelling index and the membrane permeability. The results of the analysis, FTIR spectra, obtained a new functional group after the addition of silica, they are Si-OH, Si-O-Si, and CO- NH2. The morphology test using CCD Microscope MS-804 results in the very tight chitosan membranes without the silica surface, it has no pores, smooth and homogeneous, while the chitosan-silica composite membrane of rice husk ash obviously has cracks and small cavities that seemed to spread out.

Greatly improved mechanical and thermal properties of chitosan by carboxyl-functionalized MoS2 nanosheets

In this work, molybdenum disulfide (MoS2) nanosheets were employed to enhance the mechanical and thermal properties of chitosan (CS), which was one of the most promising biomaterials. In order to promote a homogeneous dispersion of MoS2 and improved interface interactions between CS and fillers, carboxyl functionalization was subjected to the exfoliated MoS2 nanosheets by chemical conjugation with thioglycolic acid before compositing with CS. Afterward, the CS/MoS2–g–COOH composite films were prepared by a simple solution blending method. Micromorphology characterizations showed that MoS2–g–COOH nanosheets dispersed much better than unmodified MoS2 nanosheets, which was considered to be quite beneficial for the enhanced properties of CS nanocomposites. DMA results indicated that the mechanical properties of CS were improved by incorporating with MoS2–g–COOH nanosheets compared with neat CS and unmodified MoS2-filled CS. The thermal stability of CS/MoS2–g–COOH was also improved. This work demonstrated a promising route to prepare MoS2-based polymer nanocomposites with excellent performances.

Vertically aligned multi-layered structures to enhance mechanical properties of chitosan–carbon nanotube films

Pure chitosan and carbon nanotube (CNT)/chitosan nanocomposite films were fabricated via a sublimation-drying process at −196 °C, during which polymeric repulsion generates unique pores with multi-layered structures. The films were then transformed into multi-layered and vertically aligned multi-layered (VAM) structures by compression. Due to the cross-linking between layers, the films prepared at −196 °C showed significantly better mechanical properties than the films prepared at −78 and −20 °C. Furthermore, a peculiar phenomenon was observed in that pure chitosan which exhibited better mechanical properties than the nanocomposites. To explain these results, we suggest a model in which the VAM structure supports more load than the CNT fillers.

Effect of tributyl citrate on chitosan scaffold: chemical, physical properties, pro/anti inflammation cytokines

Scaffold design is one of the main issues for tissue engineering studies. Plasticizers are generally used to improve chemical, physical properties, and processing parameters of polymers, as well. Chitosan (CS) is one of the most studied biopolymer and commonly used in various areas, but for tissue engineering applications, the mechanical properties of CS are limited. The aim of this study was to overcome this shortcoming by using tributyl citrate (TBC) as a plasticizer and investigate the effects of CS scaffold. For this purpose, CS and TBC (3, 10 and 30 % w/w) blend sponge scaffolds were formed and chemical, mechanical and physical properties of formed scaffolds were characterized. Cytotoxicity of the scaffolds on mouse fibroblast (L929) and human monocytic cell line (THP-1) cells were investigated. Monocytes have critical role in host reaction. Therefore, to evaluate pro/anti-inflammatory properties of the material, TNF-α and IL-10 levels of macrophage cultured with scaffolds were measured. It was observed that, CS-3 blend scaffold has more tensile straight value and swelling degree than the other sample groups, 3 % TBC concentrations has no cytotoxic effect and slightly increased the pro/anti inflammation cytokines levels.

Chitosan and chitosan composites reinforced with carbon nanostructures

Chitosan is a naturally-occurring polymer that can be derived from chitin through a deacetylation process from shells of crustaceans. Chitosan is abundant, easily collected as waste and repurposed for industrial and biomedical applications. This work demonstrates that the mechanical properties of chitosan can be improved by thermomechanical processing (milling and sintering) and through reinforcement with carbon nanostructures (CNS) to form mechanically tunable composites. Thermal analysis was used to optimize the sintering conditions for chitosan and chitosan–CNS preventing unwelcome degradation. The crystallinity index (CI%), ratio among crystalline (β) and amorphous (α) phases, decreases from 57 to 18 depending on milling and sintering conditions. Although, the crystalline structure is affected during processing, Raman results demonstrated that the chitosan bonding is preserved and the added CNS percolate the chitosan. Pressing chitosan at room temperature does not guarantee consolidation, while chitosan sintered at 180°C can reach a hardness of up to 15±0.7μHV. Addition of CNS and sintering at 220°C demonstrate further benefits on hardness (26.1±0.1μHV) this hardness improvement is attributed to a grain boundary reduction and improved cohesion among chitosan and CNS. The nanohardness testing shows a unique elastic phenomenon resulting from the presence of graphene or graphitic carbon in the CNS.

Physico-functional and mechanical properties of chitosan and calcium salts incorporated fish gelatin scaffolds

Four types of fish gelatin scaffolds viz. gelatin (G), gelatin–chitosan (GC), gelatin–calcium acetate (GCA) and gelatin–chitosan–calcium acetate (GCCA) prepared were investigated for their functional properties, biomechanical strength, microstructural changes in relation to biodegradation. GC scaffold was superior with pH 3.15 and viscosity 9.40cP. Chitosan and calcium acetate improved tensile strength (TS) and Young's modulus (YM), but lowered elongation at break (EAB). GCCA scaffold possessed moderate TS of 19.6MPa, EAB of 4.76% and YM of 185MPa. Foaming ability ratio of GC scaffold was high (3.41). GCA and GCCA scaffolds remained for 4 days before complete in vitro biodegradation. GC scaffold had larger cavities (180–300μm) that were responsible for low swelling ratios and shrinkage factor. GCCA scaffold with moderate swelling rates, mechanical, functional properties and lowered biodegradation rate were found more suitable for biomedical applications.

Reinforced Materials Based on Chitosan, TiO2 and Ag Composites

This study investigates the mechanical reinforcement of chitosan with TiO2 and Ag nanoparticles, as well as their water vapour transmission rates and water resistance behaviour. The mechanical properties of chitosan were improved by addition of TiO2 or Ag, with significant increases in Young’s modulus (from 25 MPa to ~300 MPa), tensile strength (from 6 MPa to 18–35 MPa) and toughness (from 1.3 J g−1 to 7–8 J g−1). The water vapour transmission rates (368–413 g m−2 d−1) were found to be similar for both materials. Inclusion of Ag reduced the water resistance (from 823% to 1,000%), while inclusion of TiO2 yielded significant improvement in water resistance (from 823% to 100%).

Preparation and Evaulation of Degradable Poly(lactic acid) Composite Dressings

Chitosan and sodium alginate are two prominent biomaterials because they have some unique properties such as good biocompatible and biodegradable. In this study, sodium alginate was as swelling and moisture retention layer; Chitosan was antibacterial layer.Polylactic acid (PLA) blended in different weight ratios with low melting point polylactic acid (LMPLA) to fabricate nonwoven fabric which reinforced by needle punching and hot pressing. Afterward, chitosan/ sodium alginate compound solution were treated by UV light in order to form cross-linking. Then chitosan/ sodium alginate compound solution coated on the PLA nonwoven fabric to make PLA composite dressings. The mechanical properties of chitosan/ sodium alginate membrane and dressing were measured. The optimum parameters of chitosan/sodium alginate composite membrane was treated by UV light for five minutes and the volume ratio of chitosan (3 wt %) and sodium alginate (1 wt %) solution was 8:2. After we coated chitosan/sodium alginate solution on PLA nonwoven fabric, the Tensile strength, and tear strength were upgraded by 80 % and 98 %; its air permeability and flexibility length, however, dropped by 18 % and 60 %, respectively.

Mucoadhesive and Elastic Films Based on Blends of Chitosan and Hydroxyethylcellulose

Mucoadhesive polymeric films have been prepared based on blends of chitosan and hydroxyethylcellulose. The blends have been characterized by IR spectroscopy, DSC, WAXD, TGA, SEM, and mechanical testing. It is demonstrated that the mechanical properties of chitosan are improved significantly upon blending with hydroxyethylcellulose. An increase in hydroxyethylcellulose content in the blends makes the materials more elastic. The thermal treatment of the blends at 100 degrees C leads to partial cross-linking of the polymers and formation of water-insoluble but swellable materials. The adhesion of the films towards porcine buccal mucosa decreases with increasing hydroxyethylcellulose content in the blends.

Structure and Mechanical Properties of Chitosan/Poly(Vinyl Alcohol) Blend Films

AbstractSummary: The origins of the thermal and mechanical properties of chitosan and poly(vinyl alcohol) (PVA) with inter‐ and intra‐hydrogen bonds were investigated systematically by using X‐ray, DSC, positron annihilation and viscoelastic measurements. Based on their individual properties, the characteristics of the blend films were estimated in relation to their morphology and mechanical properties as a function of chitosan content. The characteristics of the blend films were also analyzed in terms of the deviation from a simple additive rule of chitosan and PVA content. These results suggested that the miscibility of chitosan and PVA could be ensured by entanglement of the amorphous chain segments of chitosan and PVA. Further detailed analysis revealed that the chitosan content on the film surface is higher than that of the admixture content of chitosan after elongation, although the chitosan and PVA chains were crystallized independently. The elongation could be achieved for the blend films whose PVA content was higher than 50% and the drawn blend films were transparent. Thus, it may be expected that sufficiently entangled meshes formed between chitosan and PVA amorphous chains within the film, the PVA content being higher than 50%, were maintained under the elongation process.