Mechanical Properties of Herbal Patches from Chitosan-Based Polymer Blends for Medical Applications

2018 ◽  
Vol 917 ◽  
pp. 52-56
Author(s):  
Jirapornchai Suksaeree

Recently, Thai herbs are widely used as medicine to treat some illnesses. Zingiber cassumunar Roxb., known by the Thai name “Plai”, is a popular anti-inflammatory, antispasmodic herbal body and muscle treatment. This research aimed to prepare herbal patches that incorporated the 3 g of crude Z. cassumunar oil. The herbal patches made from different polymer blends were 2 g of 3.5%w/v chitosan and 5 g of 20%w/v hydroxypropyl methylcellulose (HPMC), or 2 g of 3.5%w/v chitosan and 5 g of 20%w/v polyvinyl alcohol (PVA) using 2 g of glycerin as a plasticizer. They were prepared by mixing all ingredients in a beaker and produced by solvent casting method in hot air oven at 70±2oC. The completed herbal patches were evaluated for their mechanical properties including Young’s modulus, ultimate tensile strength, elongation at break, T-peel strength, and tack adhesion. The thickness of blank and herbal patches was 0.263-0.282 mm and 0.269-0.275 mm, respectively. Young’s modulus, ultimate tensile strength, elongation at break, T-peel strength, and tack adhesion were 104.73-142.71 MPa, 87.92-93.28 MPa, 154.39-174.98 %, 3.43-4.88 MPa, and 5.29-7.02 MPa, respectively, for blank patches, and 116.83-147.28 MPa, 89.49-100.47 MPa, 133.78-159.27 %, 2.01-3.98 MPa, and 4.03-5.19 MPa, respectively, for herbal patches. We prepared herbal blended patches made from chitosan/PVA or chitosan/HPMC polymer matrix blends incorporating the crude Z. cassumunar oil. They had good mechanical properties that might be developed for herbal medicinal application.

2012 ◽  
Vol 3 (1) ◽  
pp. 13-26
Author(s):  
Myrtha Karina ◽  
Lucia Indrarti ◽  
Rike Yudianti ◽  
Indriyati

The effect of castor oil on the physical and mechanical properties of bacterial cellulose is described. Bacterial cellulose (BC) was impregnated with 0.5–2% (w/v) castor oil (CO) in acetone–water, providing BCCO films. Scanning electron micrographs revealed that the castor oil penetrated the pores of the bacterial cellulose, resulting in a smoother morphology and enhanced hydrophilicity. Castor oil caused a slight change in crystallinity indices and resulted in reduced tensile strength and Young's modulus but increased elongation at break. A significant reduction in tensile strength and Young's modulus was achieved in BCCO films with 2% castor oil, and there was an improvement in elongation at break and hydrophilicity. Impregnation with castor oil, a biodegradable and safe plasticiser, resulted in less rigid and more ductile composites.


1981 ◽  
Vol 12 ◽  
Author(s):  
J. Bevk ◽  
W. A. Sunder ◽  
G. Dublon ◽  
David E. Cohen

ABSTRACTElastic and plastic properties of in situ Cu-based composites with Nb, V, and Fe filaments are reviewed. The evidence is presented for a pronounced size dependence of both the ultimate tensile strength and the Young's moduli. In composites with the smallest filaments (d∼50–200Å) and filament densities as high as 1010/cm2 dislocation density reaches values of 1013 cm/cm3. The yield stress of these samples increases dramatically over the predictions based on the “rule of mixtures” and their ultimate tensile strength approaches the estimated theoretical strength of the material (∼2.7GPa). The observed decrease of Young's modulus as a function of inverse wire diameter in the as-drawn composites is attributed to lattice softening due to high density of extended lattice defects. Upon annealing, Young's modulus increases by as much as 100% and exceeds the maximum values calculated from bulk elastic constants. Possible mechanisms leading to modulus enhancement and to related changes in magnetic and superconducting behavior of in situ composites are discussed.


Nano Futures ◽  
2021 ◽  
Author(s):  
Bowen Zheng ◽  
Zeyu Zheng ◽  
Grace Gu

Abstract Graphene aerogels, a special class of 3D graphene assemblies, are well known for their exceptional combination of high strength, lightweightness, and high porosity. However, due to microstructural randomness, the mechanical properties of graphene aerogels are also highly stochastic, an issue that has been observed but insufficiently addressed. In this work, we develop Gaussian process metamodels to not only predict important mechanical properties of graphene aerogels but also quantify their uncertainties. Using the molecular dynamics simulation technique, graphene aerogels are assembled from randomly distributed graphene flakes and spherical inclusions, and are subsequently subject to a quasi-static uniaxial tensile load to deduce mechanical properties. Results show that given the same density, mechanical properties such as the Young’s modulus and the ultimate tensile strength can vary substantially. Treating density, Young’s modulus, and ultimate tensile strength as functions of the inclusion size, and using the simulated graphene aerogel results as training data, we build Gaussian process metamodels that can efficiently predict the properties of unseen graphene aerogels. In addition, statistically valid confidence intervals centered around the predictions are established. This metamodel approach is particularly beneficial when the data acquisition requires expensive experiments or computation, which is the case for graphene aerogel simulations. The present research quantifies the uncertain mechanical properties of graphene aerogels, which may shed light on the statistical analysis of novel nanomaterials of a broad variety.


2020 ◽  
Vol 859 ◽  
pp. 9-14
Author(s):  
Thaniya Wunnakup ◽  
Chaowalit Monton ◽  
Laksana Charoenchai ◽  
Duangdeun Meksuriyen

The objective of this study was to apply rice bran protein hydrolysates (RBH) as bioactive additives of gelatin/Eudragit® NE 30D film and characterize the physicochemical and mechanical properties of its. The RBH was obtained by extraction with 2% sodium chloride (RBH-NaCl) and 0.1 N sodium hydroxide (RBH-NaOH) followed by digestion with Alcalase®. Then, RBH was incorporated in gelatin/Eudragit® NE 30D film. Effect of RBHs on film thickness, moisture content, pH, Young's modulus, tensile strength and the elongation at break were investigated. The RBH-NaCl enriched film showed non-homogeneous mixture and reduced moisture content, tensile strength and the elongation at break (1.8 – 2 folds). However, the RBH-NaOH enriched film exhibited a few non-homogeneous mixture and the Young's modulus was slightly decreased. The pH value was increased in the range of 6.77 – 6.88. Our results provide insight for the potential to develop RBH containing films as topical products.


Author(s):  
Mousa Younesi ◽  
Mohammad Ebrahim Bahrololoom ◽  
Hamidreza Fooladfar

This paper focuses on the effects of pressure and temperature in hot press molding on the mechanical properties of polypropylene-hydroxyapatite composites with two different types of silanated and unsilanated hydroxyapatite. Density, crystallinity, ultimate tensile strength, Young’s modulus and impact resistance were evaluated for the two types of composites. Increasing pressure caused enhancement of density, crystallinity, MFI, ultimate tensile strength and Young’s modulus. Increases in temperature increased MFI, ultimate tensile strength and Young’s modulus whilst decreased impact resistance of composites. Effects of increasing pressure and temperature on the mechanical properties of polypropylene-silanated hydroxyapatite were less than their effects on the mechanical properties of polypropylene-unsilanated hydroxyapatite. Micrographs showed changes in fracture mode from ductile to brittle with increasing pressure and temperature during hot press molding.


2006 ◽  
Vol 312 ◽  
pp. 233-236 ◽  
Author(s):  
Ke Wang ◽  
Pascal Ogier ◽  
Chauhari Wuiwui Tjiu ◽  
Chaobin He

Alumina nano-crystals were dispersed in epoxy resin via different approaches. The effects of filler dispersion on the mechanical properties of the epoxy/alumina nanocomposites were studied. The fracture mechanisms are investigated using SEM. The results show that the Young’s modulus, tensile strength, elongation at break and fracture toughness of epoxy were improved dramatically with the incorporation of well-dispersed alumina nano-crystals. The poorly-dispersed nano-crystals, however, showed little effects on the mechanical properties.


Composites films with higher mechanical properties from naturally occurring degradable materials are of present demand to achieve goals of sustainable development. Interaction within composite constituents during drying controls mechanical properties. Here, bio-nanocomposites films were first prepared from cellulose nanocrystals synthesized from jute fibres and extracted potato starch with the same chemical formulations. The filler, nanocrystals consist of nanorod-like cellulose particles obtained as an aqueous suspension by sulfuric acid (H2SO4) hydrolysis of jute fibres and the matrix was prepared by plasticization of potato starch after disruption of starch granules with water and glycerin. Nanocomposite films were obtained by casting the homogeneous aqueous suspension at 95oC and followed by natural drying (atmospheric drying, 25oC) and oven drying at 40oC. The thickness of the bio-nanocomposites film about 250 μm was controlled by using a 2 mm thick structural glass frame. It is revealed that with increasing the percentage of cellulose nanocrystals in composite films, mechanical properties corresponding to tensile strength and Young’s modulus were increased significantly. The film containing the highest quantity of cellulose nanocrystals (20% w/w of starch) revealed better properties in case of natural drying (tensile strength 84.2 MPa, Young’s modulus 0.563 GPa, elongation at break 27%) than the film properties (tensile strength 35.2 MPa, Young’s modulus 0.423 GPa, elongation at break 20%) of oven drying.


2012 ◽  
Vol 488-489 ◽  
pp. 691-695
Author(s):  
Saowaroj Chuayjuljit ◽  
Thitima Rupunt

The focus of this study is to investigate the influences of ethylene octene copolymer (EOC) and carbon nanotubes (CNTs) on the mechanical properties (tensile and flexural properties) and thermal stability of polypropylene (PP)-based thermoplastic elastomer nanocomposites. The PP/EOC blends were prepared at two different weight ratios, 80/20 and 70/30 (w/w) PP/EOC, and each blend was compounded with a very low loading of CNTs (0.5-2 parts by weight per hundred of the PP/EOC resin). Both PP/EOC blends exhibited a higher elongation at break but a lower tensile strength, Young’s modulus and flexural strength as compared with those of the neat PP. However, the addition of CNTs caused a slightly change in the tensile strength and flexural strength but a more significant change in the Young’s modulus and elongation at break. The Young’s modulus and elongation at break of the PP/EOC blends were improved by filling with the appropriate loading of the CNTs. Thus, the combined use of EOC and CNTs can provide the balanced mechanical properties to the PP. Moreover, thermogravimetric analysis showed an improvement in the thermal stability of PP by the presence of both EOC and CNTs.


2018 ◽  
Vol 33 (3) ◽  
pp. 289-304 ◽  
Author(s):  
Kuhananthan Nanthakumar ◽  
Chan Ming Yeng ◽  
Koay Seong Chun

This research covers the preparation of poly(lactic acid) (PLA)/sugarcane leaves fibre (SLF) biofilms via a solvent-casting method. The results showed that the tensile strength and Young’s modulus of PLA/SLF biofilms increased with the increasing of SLF content. Nevertheless, the elongation at break showed an opposite trend as compared to tensile strength and Young’s modulus of biofilms. Moreover, water absorption properties of PLA/SLF biofilms increased with the increasing of SLF content. In contrast, the tensile strength and Young’s modulus of biofilms were enhanced after bleaching treatment with hydrogen peroxide on SLF, but the elongation at break and water absorption properties of bleached biofilms were reduced due to the improvement of filler–matrix adhesion in biofilms. The tensile and water properties were further discussed using B-factor and Fick’s law, respectively. Furthermore, the functional groups of unbleached and bleached SLF were characterized by Fourier transform infrared analysis.


2021 ◽  
Author(s):  
Yanhong Jin ◽  
Yuanyuan Jing ◽  
Wenxin Hu ◽  
Jiaxian Lin ◽  
Yu Cheng ◽  
...  

Abstract Lignin has been used as a sustainable and eco-friendly filler in composite fibers. However, lignin aggregation occurred at high lignin content, which significantly hindered the further enhancement of fiber performance. The incorporation of graphene oxide (GO) enhanced the mechanical properties of the lignin/poly(vinyl alcohol) (PVA) fibers and affected their structure. With the GO content increasing from 0 to 0.2%, the tensile strength of 5% lignin/PVA fibers increased from 491 MPa to 631 MPa, and Young's modulus increased from 5.91 GPa to 6.61 GPa. GO reinforced 30% lignin/PVA fibers also showed the same trend. The tensile strength increased from 455 MPa to 553 MPa, and Young's modulus increased from 5.39 GPa to 7 GPa. The best mechanical performance was observed in PVA fibers containing 5% lignin and 0.2% GO, which had an average tensile strength of 631 MPa and a Young’s modulus of 6.61 GPa. The toughness values of these fibers are between 9.9-15.6 J/g, and the fibrillar and ductile fracture microstructure were observed. Structure analysis of fibers showed that GO reinforced 5% lignin/PVA fibers had higher crystallinity, and evidence of hydrogen bonding among GO, lignin, and PVA in the gel fibers was revealed. Further, water resistance and swelling behavior of composite PVA fibers were studied to further evidence the structure change of composite fibers.


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