Preparation and Characterization of Cassava Starch-Chitosan/Montmorillonite Nanocomposites

2011 ◽  
Vol 194-196 ◽  
pp. 484-487 ◽  
Author(s):  
Xian Zhong Mo ◽  
Chen Mo ◽  
Xiang Qi ◽  
Ren Huan Li

Biopolymer cassava starch(ST)-chitosan(CS)/montmorillonite(MMT) nanocomposites were prepared in which MMT was used as nanofiller and diluted acetic acid was used as solvent for dissolving and dispersing cassava starch, chitosan and MMT. XRD and TEM results indicated the formation of an exfoliated nanostructure of ST-CS/MMT nanocomposites. Mechanical properties testing revealed that at the range of the MMT content from 1wt% to 5wt%, tensile strength of the composites increased from 30MPa to 37.5MPa. But the elongation at break fall from 28% to 22% with the increasing of MMT. Obviously, MMT had an enforced effect to the composites. TGA results showed that the nano-dispersed MMT improved the thermal stability of the matrix systematically with the increasing of MMT.

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.


2014 ◽  
Vol 960-961 ◽  
pp. 262-269
Author(s):  
Ke Chen ◽  
Rui Wang

The natural rubber/polyvinyl alcohol (NR/PVA) blends containing various compatilizers grafted from NR were prepared using latex compounding techniques. The effects of various compatilizers on the morphology, mechanical properties and thermal behaviors were studied. The interface compatible performance of the blends were greatly improved with the presence of the compatilizers, and the phase dispertion of the blends achieved the best effect under the action of epoxidized natural rubber (ENR). The onset temperature of the thermal decomposition of ENR and graft copolymerization of methyl methacrylate (MMA) onto NR (NR-g-PMMA) increased obviously, but the maleic anhydride grafted onto NR (NR-g-MAH) drop obviously comparing to that of NR. The thermal stability of the blends were inferior to NR. With the presence of ENR, the tensile strength and elongation at break obtained great value which was ascribed the presence of the best phase dispertion, while the tear strength and shore A hardness obtained great value due to the addition of MAH-g-NR.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yongfang Qian ◽  
Zhen Zhang ◽  
Laijiu Zheng ◽  
Ruoyuan Song ◽  
Yuping Zhao

Design and fabrication of nanofibrous scaffolds should mimic the native extracellular matrix. This study is aimed at investigating electrospinning of polycaprolactone (PCL) blended with chitosan-gelatin complex. The morphologies were observed from scanning electron microscope. As-spun blended mats had thinner fibers than pure PCL. X-ray diffraction was used to analyze the degree of crystallinity. The intensity at two peaks at 2θof 21° and 23.5° gradually decreased with the percentage of chitosan-gelatin complex increasing. Moreover, incorporation of the complex could obviously improve the hydrophilicity of as-spun blended mats. Mechanical properties of as-spun nanofibrous mats were also tested. The elongation at break of fibrous mats increased with the PCL content increasing and the ultimate tensile strength varied with different weight ratios. The as-spun mats had higher tensile strength when the weight ratio of PCL to CS-Gel was 75/25 compared to pure PCL. Both as-spun PCL scaffolds and PCL/CS-Gel scaffolds supported the proliferation of porcine iliac endothelial cells, and PCL/CS-Gel had better cell viability than pure PCL. Therefore, electrospun PCL/Chitosan-gelatin nanofibrous mats with weight ratio of 75/25 have better hydrophilicity mechanical properties, and cell proliferation and thus would be a promising candidate for tissue engineering scaffolds.


2013 ◽  
Vol 681 ◽  
pp. 256-259
Author(s):  
Xiu Qi Liu ◽  
He Qin Xing ◽  
Li Li Zhao ◽  
Dan Wang

In our study, a new kind of foam composite was prepared by melt blending with PVC as the matrix and carbon black (CB) as the filler, the standard-spline was made in the dumbbell system prototype. Tensile strength and elongation at break were measured at 25°C。When the CB was added greater than 2.0%, with the increase of CB added, the determination of sample mechanical index began to decline, when the CB content was greater than 9%, tensile strength and elongation at break of the composites remained basically unchanged.


Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3236
Author(s):  
Peng Yin ◽  
Wen Zhou ◽  
Xin Zhang ◽  
Bin Guo ◽  
Panxin Li

In order to improve the mechanical properties and water resistance of thermoplastic starch (TPS), a novel reinforcement of dialdehyde lignocellulose (DLC) was prepared via the oxidation of lignocellulose (LC) using sodium periodate. Then, the DLC-reinforced TPS composites were prepared by an extrusion and injection process using glycerol as a plasticizer. The DLC and LC were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the effects of DLC content on the properties of the DLC/TPS composites were investigated via the evaluation of SEM images, mechanical properties, thermal stability, and contact angles. XRD showed that the crystallinity of the DLC decreased due to oxidation damage to the LC. SEM showed good dispersion of the DLC in the continuous TPS phase at low amounts of DLC, which related to good mechanical properties. The tensile strength of the DLC/TPS composite reached a maximum at a DLC content of 3 wt.%, while the elongation at break of the DLC/TPS composites increased with increasing DLC content. The DLC/TPS composites had better thermal stability than the neat TPS. As the DLC content increased, the water resistance first increased, then decreased. The highest tensile strength and elongation at break reached 5.26 MPa and 111.25%, respectively, and the highest contact angle was about 90.7°.


2017 ◽  
Vol 26 (5) ◽  
pp. 096369351702600 ◽  
Author(s):  
Wenjing Xia ◽  
Nianqing Zhu ◽  
Zhongbin Ni ◽  
Mingqing Chen

Biodegradable composites from poly (butylene succinate-co-butylene adipate) (PBSA) and Taihu Lake (Wuxi, China) blue algae were prepared by melt blending. The property and structure of biocomposites were investigated. By adding extra amount of water to blue algae, the formulated blue algae acted as a plastic in the composites during blending, and exhibited a reinforcing effect on the PBSA matrix. With increasing blue algae content, the thermal stability of the composites decreased; the tensile strength at break and elongation at break of the composites reduced, but the Young's modulus of the composites increased. However, the composite with 30% blue algae loading still exhibited good mechanical performance (tensile strength at break of 21.3 MPa, elongation at break of 180%). The fabrication of value-added PBSA/algae composites appeared as an effective approach to reduce the secondary environmental pollution of Taihu blue algae.


2019 ◽  
Vol 947 ◽  
pp. 77-81
Author(s):  
Natsuda Palawat ◽  
Phasawat Chaiwutthinan ◽  
Sarintorn Limpanart ◽  
Amnouy Larpkasemsuk ◽  
Anyaporn Boonmahitthisud

The aim of this study is to improve the physical properties of poly(lactic acid) (PLA) by incorporating thermoplastic polyurethane (TPU), organo-montmorillonite (OMMT) and/or nanosilica (nSiO2). PLA was first melt mixed with five loadings of TPU (10–50 wt%) on a twin-screw extruder, followed by injection molding. The addition of TPU was found to increase the impact strength, elongation at break and thermal stability of the blends, but decrease the tensile strength and Young’s modulus. Based on a better combination of the mechanical properties, the 70/30 (w/w) PLA/TPU blend was selected for preparing both single and hybrid nanocomposites with a fix total nanofiller content of 5 parts per hundred of resin (phr), and the OMMT/nSiO2 weight ratios were 5/0, 2/3, 3/2 and 0/5 (phr/phr). The Young’s modulus and thermal stability of the nanocomposites were all higher than those of the neat 70/30 PLA/TPU blend, but at the expense of reducing the tensile strength, elongation at break and impact strength. However, all the nanocomposites exhibited higher impact strength and Young’s modulus than the neat PLA. Among the four nanocomposites, a single-filler nanocomposite containing 5 phr nSiO2 exhibited the highest impact strength and thermal stability, indicating that there was no synergistic effect of the two nanofillers on the investigated physical properties. However, the hybrid nanocomposite containing 2/3 (phr/phr) OMMT/nSiO2 possessed a compromise in the tensile properties.


2008 ◽  
Vol 584-586 ◽  
pp. 960-965 ◽  
Author(s):  
Tamara Kravchenko ◽  
Alexander Korshunov ◽  
Natalia Zhdanova ◽  
Lev Polyakov ◽  
Irina Kaganova

Annealed oxygen-free and tough-pitch copper samples have been processed by equalchannel angular pressing (ECAP) by route BC. The samples included 8 x 8 mm section pieces and a 40 mm diameter bar. Thermal stability was assessed based on the changes in the standard mechanical properties (conventional yield strength, tensile strength, elongation, proportional elongation and contraction) after annealing at different temperatures for 1 hour. Thermal stability of the same grade of material has been found to be different for different batches and to depend on the structural conditions of deformed material. The zone of thermal stability for copper of the two grades of interest does not depend on the material’s chemical composition.


2012 ◽  
Vol 727-728 ◽  
pp. 609-613
Author(s):  
P.C.F. Menezes ◽  
Taciana Regina de Gouveia Silva ◽  
Ana Cristina Figueiredo de Melo Costa ◽  
Edcleide Maria Araújo

The research in composites attempt to predict the physico-chemical and mechanical a given mixture of materials. In this work, a composite was produced using as the polyamide 6 matrix and how the burden of nickel ferrite was incorporated as powders calcined at 1200°C and concentration of 50 wt.%. This mixture was compacted in a hydraulic press with heating and characterized by XRD, SEM and TG. XRD results showed the characteristic peaks of polyamide 6 and ferrite. SEM results showed a good dispersion of nickel ferrite loading in the matrix, the presence of larger clusters and evenly distributed load for the composite calcined at 1200 ° C. TG curves showed that the addition of loading of calcined nickel ferrite promoted an increase in thermal stability of the composite compared to pure polyamide.


2011 ◽  
Vol 380 ◽  
pp. 290-293
Author(s):  
Bing Tao Wang ◽  
Ping Zhang ◽  
De Gao

In situ melt copolycondensation was proposed to prepare biodegradable copolyester nanocomposites based on degradable components poly(L-lactic acid) (PLA), rigid segments poly(butylene terephthalate) (PBT), and nanoparticles polyhedral oligomeric silsesquioxanes (POSS). The morphologies and dispersions of two POSS nanoparticles (POSS-NH2 and POSS-PEG) in the copolyester PLABT matrix and their effects on the mechanical properties were investigated. The results demonstrated that the morphologies and dispersions of POSS-NH2 and POSS-PEG showed quite different characteristics. POSS-PEG took better dispersion in the PLABT, while POSS-NH2 had poor dispersions and formed crystalline microaggregates. Due to the good dispersion and strong interfacial adhesion of POSS-PEG with the matrix, the tensile strength and Young’s modulus were greatly improved from 6.4 and 9.6 MPa for neat PLABT up to 11.2 and 70.7 MPa for PLABT/POSS-PEG nanocomposite. Moreover, the incorporation of POSS-PEG could impart macromolecular chains good flexibility and improve the mobility of the chains, so the the elongation at break of PLABT/POSS-PEG nanocomposite dramatically increased from 190 to 350 % compared with neat PLABT.


Sign in / Sign up

Export Citation Format

Share Document