scholarly journals Mechanical Properties and Structures of Clay-Polyelectrolyte Blend Hydrogels

Gels ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 71 ◽  
Author(s):  
Hiroyuki Takeno ◽  
Shiori Nagai
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Interparticle Distance ◽  
Sodium Polyacrylate ◽  
Inhomogeneous Distribution ◽  
X Ray ◽  
X Ray Scattering ◽  
Local Ordering ◽  
Local Aggregation ◽  
Clay Platelets

Our recent studies have shown that the hydrogels prepared by blending clay, a dispersant of clay, and a polyelectrolyte (sodium polyacrylate (PAAS)) possess excellent mechanical properties. In order to clarify the mechanism of the toughness, we have so far investigated the effects of the composition, molecular mass of the polymer, and kinds of polymers on the mechanical properties. This study has focused upon the mechanical properties and structures of the clay/PAAS gels using three kinds of smectite clay minerals such as synthetic hectorite (laponite XLG), saponite (sumecton-SA), montmorillonite (kunipia-F), whose particle size becomes larger according to the sequence. Laponite/PAAS and sumecton/PAAS gels were quite tough for high compression, whereas kunipia-F/PAAS did not gelate. In comparison between sumecton/PAAS gel and laponite/PAAS gel, the mechanical property of the former gel was poorer than that of the latter gel due to the inhomogeneous distribution of clay platelets in the gel. Synchrotron small-angle X-ray scattering experiments revealed that their clay platelets laid down in the stretching direction under elongation. Furthermore, it was found that sumecton/PAAS gel under elongation was arranged with an interparticle distance of ~6.3 nm in the direction perpendicular to the stretching. Such local ordering under elongation may originate in local aggregation of sumecton platelets in the original state without elongation.

scholarly journals Conformation and mechanical property of rpoS mRNA inhibitory stem studied by optical tweezers and X-ray scattering

PLoS ONE ◽  
2019 ◽  
Vol 14 (9) ◽  
pp. e0222938
Author(s):  
Xinyao Hu ◽  
Xuanling Li ◽  
Lingna Yang ◽  
Yilin Zhu ◽  
Yunyu Shi ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Optical Tweezers ◽  
X Ray ◽  
X Ray Scattering ◽  
Rpos Mrna ◽  
Ray Scattering

Anomalous X-ray Scattering (AXS) Study on the Local Ordering Structure around Ni and Cu in Amorphous Pd40Ni10Cu30P20Alloy

1999 ◽  
Vol 38 (S1) ◽  
pp. 448 ◽  
Author(s):  
Changyong Park ◽  
Masatoshi Saito ◽  
Nobuyuki Nishiyama ◽  
Akihisa Inoue ◽  
Yoshio Waseda
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Local Ordering ◽  
Ray Scattering

Structure Evolution of Thermotropic Polymers by Thermal Annealing. A Light and X-Ray Scattering Study

2015 ◽  
Vol 1765 ◽  
pp. 65-70
Author(s):  
Adriana Reyes-Mayer ◽  
Angel Romo-Uribe ◽  
Michael Jaffe
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Treatment ◽  
Structure Evolution ◽  
Wide Angle ◽  
Extrusion Axis ◽  
X Ray ◽  
X Ray Scattering ◽  
Extruded Films ◽  
Ray Scattering

ABSTRACTSmall-angle light scattering (SALS) and wide-angle X-ray scattering (WAXS) were used to study the influence of heat treatment on the texture and microstructure of extruded films of high-performance thermotropic liquid crystal polymers (LCPs). The microstructure was correlated with tensile mechanical properties. LCPs based on random units of hydroxybenzoic acid (B), hydroxynaphthoic acid (N), terephthalic acid (TA) and biphenol (BP) were supplied by the former Hoechst Celanese Corp. as 50 μm thick extruded films. The LCPs, denoted B-N, COTBP and RD1000, have B and N as common co-monomers and vary the other co-monomers. Thus, this study also enabled the investigation of the influence of monomer composition on microstructure and mechanical properties. Heat treatments were carried out at temperatures close to the solid-to-nematic transition (Ts→n) for periods up to 5 h, under dry air conditions. The thermal treatment produced either two endotherms or a small increase of Ts→n (B-N and RD1000), or Ts→n increased significantly (COTBP). Moreover, when heat treatment was carried out approximately 40°C below the respective Ts→n, the mechanical Young’s modulus, E, along the extrusion axis increased for all LCPs. Strikingly, for COTBP, E increased over 100% relative to the as-extruded film. The results also showed that the optimum treatment time for improving the Young modulus was between 3 and 4 h. Wide-angle X-ray scattering showed a significant sharpening of crystalline reflections and concentration of the 002 meridional reflection as a result of thermal treatment, suggesting the elimination of defects and a better alignment of the molecular chains along the extrusion axis. This would explain the increase in tensile modulus.

scholarly journals Preparation of Xylan-g-/P(AA-co-AM)/GO Nanocomposite Hydrogel and its Adsorption for Heavy Metal Ions

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 621 ◽  
Author(s):  
Weiqing Kong ◽  
Minmin Chang ◽  
Chunhui Zhang ◽  
Xinxin Liu ◽  
Bei He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Adsorption Capacity ◽  
Heavy Metal Ions ◽  
Raw Materials ◽  
Ammonium Persulfate ◽  
Maximum Adsorption Capacity ◽  
Nanocomposite Hydrogel ◽  
X Ray ◽  
Nanocomposite Hydrogels

Xylan-g-/P(AA-co-AM)/Graphene oxide (GO) hydrogels were prepared and used in the removal of heavy mental ions. Acrylamide (AM), acrylic acid (AA), and xylan were used as the raw materials to prepare the hydrogels with ammonium persulfate (APS) as the initiator. The prepared hydrogels were characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and energy dispersive X-ray (EDX). Some important properties of nanocomposite hydrogels such as swelling behavior, mechanical property, and adsorption capacity were also examined as well as the regeneration of the hydrogels. The results showed that the prepared hydrogels reached the equilibrium state of swelling after 12 h, and the compressive strength of the hydrogel with 30 mg of GO could reach up to 203 kPa. Compared with traditional hydrogel, the mechanical properties of the hydrogels with GO were obviously improved. The maximum adsorption capacity of hydrogels for Pb2+, Cd2+, and Zn2+ could reach up to 683 mg/g, 281 mg/g, and 135 mg/g, respectively. After five cycles of adsorption and desorption, the recovery rate of the hydrogels on Pb2+, Cd2+, and Zn2+ was still up to 87%, 80%, and 80%, respectively—all above 80%.

Comparative Studies on Photoelasticity of Elastomers and Plastomers

1948 ◽  
Vol 21 (4) ◽  
pp. 790-798
Author(s):  
Wilfried Heller ◽  
Hans Oppenheimer
Keyword(s):  
Mechanical Properties ◽  
Film Structure ◽  
Polymer Chains ◽  
X Ray Diffraction ◽  
Photoelastic Method ◽  
Double Refraction ◽  
X Ray ◽  
Transparent Films ◽  
X Ray Scattering

Abstract Transparent films of elastomers and plastomers were found to differ sufficiently in their photoelastic behavior to make stress double refraction a useful criterion of the prospective mechanical properties of a given material. The stress double refraction in such films is mostly an effect of deformation, of orientation, or of both deformation and orientation of polymer chains. In such polymers, however, which crystallize under stress, a large part of the optical effect may be due to oriented crystallization. In addition to its practical value as a testing method for polymers, the photoelastic method offers, therefore, particularly in combination with simultaneous investigations of mechanical properties, the prospect of correlating mechanical properties of a polymer film with its internal structure, and of correlating changes in both qualities on exposure of the film to different degrees of stress. Although results obtained on such films, by means of x-ray diffraction or x-ray scattering and electron-diffraction, are, in general, easier to interpret, the photoelastic method has the considerable advantage of making possible a quantitative follow-up of rapid changes in film structure, e.g., of relaxations.

scholarly journals Preparation and Characterization of HPMC/PVP Blend Films Plasticized with Sorbitol

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
H. Somashekarappa ◽  
Y. Prakash ◽  
K. Hemalatha ◽  
T. Demappa ◽  
R. Somashekar
Keyword(s):  
Mechanical Properties ◽  
Hydroxypropyl Methylcellulose ◽  
Solution Casting ◽  
Casting Method ◽  
Elongation At Break ◽  
X Ray ◽  
Blend Films ◽  
X Ray Scattering ◽  
Solution Casting Method

The aim of this present work is to investigate the effect of plasticizers like Sorbitol on microstructural and mechanical properties of hydroxypropyl methylcellulose (HPMC) and Polyvinylpyrrolidone (PVP) blend films. The pure blend and plasticized blend films were prepared by solution casting method and investigated using wide angle X-ray scattering (WAXS) method. WAXS analysis confirms that the plasticizers can enter into macromolecular blend structure and destroy the crystallinity of the films. FTIR spectra show that there are a shift and decrease in the intensity of the peaks confirming the interaction of plasticizer with the blend. Mechanical properties like tensile strength and Young’s Modulus decrease up to 0.6% of Sorbitol content in the films. Percentage of elongation at break increases suggesting that the plasticized films are more flexible than pure blend films. These films are suitable to be used as environmental friendly and biodegradable packaging films.

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