scholarly journals Silk/Natural Rubber (NR) and 3,4-Dihydroxyphenylalanine (DOPA)-Modified Silk/NR Composites: Synthesis, Secondary Structure, and Mechanical Properties

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 235
Author(s):  
Hiromitsu Sogawa ◽  
Treratanakulwongs Korawit ◽  
Hiroyasu Masunaga ◽  
Keiji Numata
Keyword(s):  
Mechanical Properties ◽  
Secondary Structure ◽  
Natural Rubber ◽  
Chemical Structure ◽  
Attenuated Total Reflection ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superior Mechanical Properties ◽  
Effective Reinforcement ◽  
Β Sheet

Silk composites with natural rubber (NR) were prepared by mixing degummed silk and NR latex solutions. A significant enhancement of the mechanical properties was confirmed for silk/NR composites compared to a NR-only product, indicating that silk can be applied as an effective reinforcement for rubber materials. Attenuated total reflection Fourier transform infrared (ATR-FTIR) and wide-angle X-ray diffraction (WAXD) analysis revealed that a β-sheet structure was formed in the NR matrix by increasing the silk content above 20 wt%. Then, 3,4-dihydroxyphenylalanine (DOPA)-modified silk was also blended with NR to give a DOPA-silk/NR composite, which showed superior mechanical properties to those of the unmodified silk-based composite. Not only the chemical structure but also the dominant secondary structure of silk in the composite was changed after DOPA modification. It was concluded that both the efficient adhesion property of DOPA residue and the secondary structure change improved the compatibility of silk and NR, resulting in the enhanced mechanical properties of the formed composite. The knowledge obtained herein should contribute to the development of the fabrication of novel silk-based elastic materials.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HYPEREUTECTIC Al-Si/AlNp COMPOSITE

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1377-1382 ◽  
Author(s):  
SEULKI PARK ◽  
JINMYUNG CHOI ◽  
BONGGYU PARK ◽  
IKMIN PARK ◽  
YONGHO PARK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Dispersive Spectrometer ◽  
Microstructural Characterization ◽  
Weight Fraction ◽  
Reinforcement Particle ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superior Mechanical Properties ◽  
Phase Evaluation

Hypereutectic Al - Si alloys with fine and evenly distributed Si precipitates have superior mechanical properties In this study, hypereutectic Al - Si alloy powders which contained 15 and 20wt% Si were prepared by a gas atomization process. 1, 3 and 5wt% AlN particles were blended with the Al - Si alloy powders using turbular mixer. The mixture was consolidated by Hot Press at 550°C for 1h under 60MPa. Relative density of the sintered samples was about 98% of theoretical density. This study was investigated by two ways. One is the effect of reinforcement weight fraction and the other is the effect of Silicon contents on the mechanical properties of the composite. Microstructural characterization and phase evaluation were carried out using X-ray Diffraction, Scanning Electron Microscopy equipped with Energy Dispersive Spectrometer. The results showed that the smaller the reinforcement particle size was and the better its distribution was, the higher ultimate tensile strength and hardness were.

scholarly journals Novel Bovine Serum Albumin Protein Backbone Reassembly Study: Strongly Twisted β-Sheet Structure Promotion upon Interaction with GO-PAMAM

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2603
Author(s):  
Andra Mihaela Onaș ◽  
Iuliana Elena Bîru ◽  
Sorina Alexandra Gârea ◽  
Horia Iovu
Keyword(s):  
Secondary Structure ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Protein Backbone ◽  
Raman Spectrometry ◽  
X Ray ◽  
Β Sheet

This study investigates the formation of a graphene oxide-polyamidoamine dendrimer complex (GO-PAMAM) and its association and interaction with bovine serum albumin (BSA). Fourier-transform infrared spectrometry and X-ray photoelectron spectrometry indicated the formation of covalent linkage between the GO surface and PAMAM with 7.22% nitrogen content in the GO-PAMAM sample, and various interactions between BSA and GO-PAMAM, including π-π* interactions at 291.5 eV for the binding energy value. Thermogravimetric analysis highlighted the increasing thermal stability throughout the modification process, from 151 to 192 °C for the 10% weight loss temperature. Raman spectrometry and X-ray diffraction analysis were used in order to examine the complexes’ assembly, showing a prominent (0 0 2) lattice in GO-PAMAM. Dynamic light scattering tests proved the formation of stable graphenic and graphenic-protein aggregates. The secondary structure rearrangement of BSA after interaction with GO-PAMAM was investigated using circular dichroism spectroscopy. We have observed a shift from 10.9% β-sheet composition in native BSA to 64.9% β-sheet composition after the interaction with GO-PAMAM. This interaction promoted the rearrangement of the protein backbone, leading to strongly twisted β-sheet secondary structure architecture.

Biodegradable Nanocomposites of Poly(hydroxybutyrate-co-hydroxyvalerate): The Effect of Nanoparticles

2008 ◽  
Vol 8 (4) ◽  
pp. 1858-1866 ◽  
Author(s):  
Pralay Maiti ◽  
Jaya P. Prakash Yadav
Keyword(s):  
Mechanical Properties ◽  
Layered Silicate ◽  
Layered Silicates ◽  
Thermal And Mechanical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicate Nanocomposites ◽  
Transmission Electron ◽  
Superior Mechanical Properties ◽  
Biodegradable Nanocomposites

Copolymer of hydroxybutyrate and hydroxyvalerate, P(HB-HV)/layered silicate or hydroxyapatite nanocomposites were prepared via melt extrusion. The nanostructure, as observed from wide-angle X-ray diffraction and transmission electron microscopy, indicate intercalated hybrids for layered silicates. Hydroxyapatite of nanometer dimension is uniformly distributed in matrix copolymer. The nanohybrids show significant improvement in thermal and mechanical properties of the copolymer as compared to the neat copolymer. The layered silicate nanocomposites exhibit superior mechanical properties as compared to hydroxyapatite nanohybrid. The thermal expansion coefficient is significantly reduced in nanohybrids. The biodegradability of pure copolymer and its nanocomposites were studied at room temperatures under controlled conditions in compost media. The rate of biodegradation of copolymer is enhanced dramatically in the nanohybrids. Hydroxyapatite hybrid shows highest rate of biodegradation. The change in biodegradation is streamlined in terms of nature of nanoparticles used to prepare hybrids.

Effect of Processing Conditions on Properties of KMnO4-Treated PAN Fibers

2013 ◽  
Vol 821-822 ◽  
pp. 23-27
Author(s):  
Xiang Li ◽  
Chun Yi Liu ◽  
Ai Wen Qin ◽  
Xin Zhen Zhao ◽  
Chun Ju He
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Structure ◽  
Suitable Condition ◽  
Wide Angle ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron ◽  
Pan Fibers

Plasticized polyacrylonitrile(PAN) fibers have been chemically impregnated with aqueous solution of KMnO4under varying conditions of temperature and time. The effect of modification conditions on the chemical structure and the mechanical properties of precursor fibers are characterized by wide-angle X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscope. The experimental results show that KMnO4can be used not only as catalyst for cyclization reaction, but also as plasticizer. The chemical modification between KMnO4and PAN can not occur below70°C, the most suitable condition for modification is performed at 80°C for 5 min.

SYNERGISTIC REINFORCEMENT OF ORGANOCLAY AND DOUBLE NETWORKING IN NATURAL RUBBER

2013 ◽  
Vol 86 (2) ◽  
pp. 205-217 ◽  
Author(s):  
Hedayatollah Sadeghi Ghari ◽  
Zahra Shakouri
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Natural Rubber ◽  
Physical And Mechanical Properties ◽  
X Ray Diffraction ◽  
Double Network ◽  
X Ray ◽  
Extension Ratio ◽  
Curing Characteristics ◽  
Scanning Electron

ABSTRACT Research was undertaken on natural rubber (NR) nanocomposites with organoclays. A double-network (DN) structure is formed when a partially cross-linked elastomer is further cross-linked during a state of strain. Two methods were used in the preparation of NR/organoclay nanocomposites: the ordinary method (single-network NR nanocomposite) and double-networked NR (DN-NR) nanocomposites. The single-networked NR nanocomposites were used for comparison. The effects of organoclay (5 phr) with a different extension ratio on curing characteristics, mechanical properties, hardness, swelling behavior, and morphology of single- and double-networked NR nanocomposites were studied. The results showed that double-networked NR nanocomposites exhibited higher physical and mechanical properties. The tensile strength of DN-NR nanocomposites increased up to 33 MPa (more than four times greater than that of pure NR) and then decreased with an increasing extension ratio. Modulus and hardness continuously increased with an increased extension ratio. The microstructure of the NR/organoclay systems was studied by X-ray diffraction and field emission scanning electron microscopy. The effects of different extension ratios on the dispersion of organoclay layers in the nanocomposites were investigated. Generally, results showed that the optimized extension ratio in DN nanocomposites was equal (or about or around) to α= 2.

scholarly journals Preparation and properties of natural rubber/organo-montmorillonite: from lab samples to bulk material

2014 ◽  
Vol 33 (2) ◽  
pp. 249 ◽  
Author(s):  
Aleksandra Ivanoska-Dacikj ◽  
Gordana Bogoeva-Gaceva ◽  
Aleksandra Buzarovska ◽  
Igor Gjorgjiev ◽  
Luljeta Raka
Keyword(s):  
Natural Rubber ◽  
Dynamic Testing ◽  
Bulk Material ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Elongation At Break ◽  
X Ray ◽  
Roll Mill ◽  
Two Phases ◽  
Effective Reinforcement

<p>Focusing on application aspects of the rubber nanocomposites and the production and testing of industrial-sized samples, this study was performed in two phases. First, natural rubber (NR)/organo-montmorillonite (OMMT) nanocomposites containing 2–14 phr OMMT were prepared on a laboratory-sized two-roll mill. The vulcanization behavior and mechanical properties of NR/OMMT composites were compared with a referent NR compound containing 60 phr carbon black (N330) as a reinforcing filler. The x-ray diffraction (XRD) analyses showed a predominant intercalated structure for all OMMT nanocomposites. As a result, the organoclay behaved as an effective reinforcement for NR, even at loadings as low as 2 phr. This nanocomposite exhibited an improvement in tensile strength of 29% and in elongation at break of 61% in comparison with the referent NR/N330 compound. With the estimated optimal filler content, in the second phase, bulk NR/OMMT-5/steel samples were successfully produced for dynamic testing. The dynamic moduli were investigated by the method of forced vibrations. Compared to the NR/N 330 samples, NR/OMMT-5 samples showed improved hysteresis, with very low dissipating energy per cycle and significantly reduced Mullins effect.</p>

Effect of Modified Natural Rubber on Morphology, Chemical Structure, and Crystallinity of Electrospun Polyvinylidene Difluoride Nanofibers

2019 ◽  
Vol 950 ◽  
pp. 128-132
Author(s):  
Jean Raynell S. Bello ◽  
Bryan B. Pajarito ◽  
Jem Valerie D. Perez
Keyword(s):  
Natural Rubber ◽  
Chemical Structure ◽  
Fiber Diameter ◽  
Natural Rubber Latex ◽  
X Ray Diffraction ◽  
Rubber Latex ◽  
Polyvinylidene Difluoride ◽  
X Ray ◽  
Chemically Modified ◽  
Enzymatic Deproteinization

Natural rubber latex was chemically modified by enzymatic deproteinization, degradation, and epoxidation to produce deproteinized liquid epoxidized natural rubber (DP-LENR). Polyvinylidene difluoride (PVDF) was blended with DP-LENR and then electrospun to produce nanofibers. Scanning electron microscopy shows reduction in the fiber diameter and beading formation with increasing concentration of DP-LENR. Smooth surface of nanofibers suggests miscibility and chemical compatibility of PVDF with low concentration of DP-LENR. Infrared spectroscopy and X-ray diffraction analysis show the addition of DP-LENR has no effect on chemical structure and crystallinity of electrospun PVDF.

Study of Microstructure and Mechanical Properties of Sintered Aluminum Alloy Composite Reinforced with Al2O3 Nanoparticles

2013 ◽  
Vol 849 ◽  
pp. 62-68 ◽  
Author(s):  
R. Senthilkumar ◽  
N. Arunkumar ◽  
M. Manzoor Hussian ◽  
R. Vijayaraj
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Powder Metallurgy Method ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Optimum Amount ◽  
X Ray ◽  
Sintered Aluminum ◽  
Superior Mechanical Properties ◽  
Composite Samples

In this research, aluminum alloy AA2014 matrix composites reinforced with micron (10% wt 5% wt) and nanoparticles (1% wt 5% wt) of Al2O3were fabricated through powder metallurgy method. Optimum amount of reinforcement were determined by evaluating mechanical properties like micro-hardness and compressive strength of composites. The composite samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results reveal that the composites containing 2% wt of nanoAl2O3and 8 % micro Al2O3reinforcement has homogenous microstructure as well as superior mechanical properties.

Study on Aging of Zinc Oxide/Poly(butylene succinate) Composite

2013 ◽  
Vol 457-458 ◽  
pp. 108-111
Author(s):  
Chun Na Cui ◽  
Ji Tao Huang
Keyword(s):  
Mechanical Properties ◽  
Zinc Oxide ◽  
Chemical Structure ◽  
X Ray Diffraction ◽  
Characteristic Functional ◽  
Butylene Succinate ◽  
X Ray ◽  
Aging Test ◽  
Aging Properties ◽  
Properties Of Materials

Zinc oxide/poly (butylene succinate) composite (ZnO/PBS) were performed by aging test of 1008h. The chemical structure and crystallinity of the materials were characterized by fourier transform infrared spectroscopy and X-ray diffraction, and the aging properties of composite were studied by mechanical properties. The results showed that: the scale of characteristic functional groups had some change. And any of the reciprocal actions or effects, that can occur in composite molecule. The crystallinity of composite had reduced from 26.13% to 15.56% after aging. Mechanical properties of materials reduced gradually in aging, and reduced extent of ZnO/PBS composite was less than that of PBS.

scholarly journals STRUCTURES AND PROPERTIES OF NATURAL RUBBER/ORGANOCLAY NANOCOMPOSITES

2011 ◽  
Vol 14 (1) ◽  
pp. 30-38
Author(s):  
Hien Quang Pham ◽  
Son Thanh Thanh Do ◽  
Nieu Huu Nguyen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Abrasion Resistance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structures And Properties ◽  
Scanning Electron

Natural rubber (NR), 30% epoxidized natural rubber (ENR30) and organoclays (Nanomer I28E and I30E) are blended in Brabender. Dispersions of the organoclay in NR are investigated by X – ray diffraction (XRD) and scanning electron microscopy (SEM). The results revealed the increase of dispersion efficiency by the addition of ENR30 as a compatibilizer. The existence of organoclay I28E reduces the vulcanization time, while torque value increases slightly and mechanical properties (abrasion resistance, modulus M100, modulus M300, tensile strength, tear strength) are improved considerably.

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