Toughening, Thermal Stability, Flame Retardancy, and Scratch–Wear Resistance of Polymer–Clay Nanocomposites

2007 ◽  
Vol 60 (7) ◽  
pp. 496 ◽  
Author(s):  
Aravind Dasari ◽  
Szu-Hui Lim ◽  
Zhong-Zhen Yu ◽  
Yiu-Wing Mai
Keyword(s):  
Thermal Stability ◽  
Wear Resistance ◽  
Flame Retardancy ◽  
Interfacial Area ◽  
Barrier Properties ◽  
Clay Nanocomposites ◽  
Positive Effects ◽  
Large Numbers ◽  
Mechanical And Physical Properties ◽  
Wear Response

Addition of a small percent of clay to polymers improves their stiffness, strength, dimensional stability, and thermal, optical, and barrier properties. Improvements are often attributed to the availability of large numbers of clay nanolayers with tremendous interfacial area. Despite the positive effects from the addition of clay, there are unresolved issues, such as embrittlement, thermal stability, flame retardancy, scratch–wear response of the resultant nanocomposites, and/or achieving a balance between different mechanical and physical properties. In this review, we discuss these issues and the approaches that have been adopted in the expectation of resolving and understanding them, with particular emphasis on our recent and current research.

Permeability of Polymer/Clay Nanocomposites

2011 ◽  
Vol 1312 ◽  
Author(s):  
Georgios A. Choudalakis ◽  
Alexandros D. Gotsis
Keyword(s):  
Free Volume ◽  
Diffusion Length ◽  
Volume Fraction ◽  
Interfacial Area ◽  
Barrier Properties ◽  
Polymeric Matrix ◽  
Nanocomposite Coatings ◽  
Clay Nanocomposites ◽  
The Matrix ◽  
Diffusion Mechanisms

ABSTRACTBecause of their large interfacial area, the presence of nanoplatelets in the polymeric matrix decelerates the process of diffusion of gases through the material. The particles are impermeable barriers to the diffusing molecules, forcing them to follow complicated paths, increasing, thus, the diffusion length. The barrier properties of the nanocomposites depend on the properties of the polymeric matrix, the volume fraction of the nanoplatelets, their aspect ratio, their orientation, and their interactions with the matrix. The mobility of the molecules is hindered by the crystallinity but it is facilitated by the free volume within the material. The size and shape of the free volume holes in the polymer affect, thus, the rate of diffusion. Interactions between the nanoparticles and the matrix may lower the barrier properties because they may increase the free volume in the material. The estimation of free volume in the nanocomposite is important for the proper choice of components and the manufacturing of nanocomposite coatings with optimum barrier properties. Detailed information about the diffusion mechanisms at atomic and molecular levels can be obtained using the approach of free volume.

Comparison of silicate impregnation methods to reinforce Chinese fir wood

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ping Li ◽  
Yuan Zhang ◽  
Yingfeng Zuo ◽  
Yiqiang Wu ◽  
Guangming Yuan ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Heat Release ◽  
Flame Retardancy ◽  
Chinese Fir ◽  
Smoke Suppression ◽  
Impregnation Method ◽  
Residual Rate ◽  
Smoke Production ◽  
Human Respiration ◽  
Strengthen Effect

AbstractInorganic impregnation strengthening of Chinese fir wood was carried out to improve the strength, dimensional stability, flame retardancy, and smoke suppression of Chinese fir wood. Sodium silicate was used as reinforcement, a sulfate and phosphate mixtures were used as a curing agent, and Chinese fir wood was reinforced by the respiratory impregnation method (RIM) that imitating human respiration and vacuum progressive impregnation method (VPIM). The weight percentage gain (WPG), density increase rate, distribution of modifier, bending strength (BS), compressive strength (CS), hardness, and water resistance of unreinforced Chinese fir wood from the VPIM and RIM were compared. It was found that RIM could effectively open the aspirated pits in Chinese fir wood, so its impregnation effect, strengthen effect and dimension stabilization effects were the best. RIM-reinforced Chinese fir wood was filled with silicate both horizontally and vertically. At the same time, the transverse permeability of silicate through aspirated pits was significantly improved. The chemical structure, crystalline structure, flame retardancy, smoke suppression, and thermal stability of VPIM- and RIM-reinforced Chinese fir wood were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), cone calorimeter (CONE), and thermogravimetric analysis (TGA). The results indicated that although the crystallinity of RIM-reinforced Chinese fir wood decreased the most, more chemical crosslinking and hydrogen bonding were formed in the wood, and the strengthen effect was still the best. Compared with VPIM-reinforced Chinese fir wood, RIM-reinforced Chinese fir wood had lower heat release rate (HRR), peak-HRR, mean-HRR, total heat release (THR), smoke production rate (SPR), and total smoke production (TSP), higher thermal decomposition temperature and residual rate. It was indicated that RIM-reinforced Chinese fir wood was a better flame retardant, and has a smoke suppression effect, thermal stability, and safety performance in the case of fire.

scholarly journals Fabrication and characterization of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with nano-montmorillonite biocomposite

e-Polymers ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 038-046
Author(s):  
Xu Yan ◽  
Wanru Zhou ◽  
Xiaojun Ma ◽  
Binqing Sun
Keyword(s):  
Thermal Stability ◽  
Oxygen Permeability ◽  
Water Vapor Permeability ◽  
Barrier Properties ◽  
Nucleating Agent ◽  
Vapor Permeability ◽  
Casting Method ◽  
Increasing Trend ◽  
Solution Casting Method

Abstract In this study, a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with nano-montmorillonite biocomposite (MMT/PHBH) was fabricated by solution-casting method. The results showed that the addition of MMT increased the crystallinity and the number of spherulites, which indicated that MMT was an effective nucleating agent for PHBH. The maximum decomposition peak of the biocomposites moved to a high temperature and residue presented an increasing trend. The biocomposites showed the best thermal stability at 1 wt% MMT. Compared with PHBH, 182.5% and 111.2% improvement in elastic modulus and tensile strength were obtained, respectively. Moreover, the oxygen permeability coefficient and the water vapor permeability of MMT/PHBH biocomposites decreased by 43.9% and 6.9%, respectively. It was also found that the simultaneous enhancements on the crystallizing, thermal stability, mechanical, and barrier properties of biocomposites were mainly caused by the formation of intercalated structure between PHBH and MMT.

Expanded vermiculite-filled flexible polymer composites

2021 ◽  
pp. 009524432110290
Author(s):  
Mukaddes Sevval Cetin ◽  
Ozan Toprakci ◽  
Omer Suat Taskin ◽  
Abdullah Aksu ◽  
Hatice Aylin Karahan Toprakci
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Contact Angle ◽  
Polymer Composites ◽  
Flame Retardancy ◽  
Composite Films ◽  
Filler Concentration ◽  
High Shear ◽  
Flexible Polymer ◽  
Shear Mixing

This study focuses on the fabrication and characterization of vermiculite-filled flexible polymer composites. Exfoliated vermiculite was incorporated into triblock thermoplastic elastomer copolymer, styrene- b-(ethylene- co-butylene)- b-styrene (SEBS), at various levels from 1 to 15 wt% by a high shear mixer. The composite films were obtained by the combination of solvent casting and compression molding. The morphological, structural, thermal, and mechanical properties and contact angle of the composites were determined. Some micro-morphological differences were observed between the samples and the difference was assumed to be caused by high shear mixing and filler concentration. High shear mixing was found effective in terms of the detachment of vermiculite layers at all concentrations. However, at low filler loading, that behavior was more obvious. At 1 wt% filler concentration, mechanical properties increased that was probably caused by good filler-matrix interaction stemmed from smaller particle size. At higher vermiculite concentrations, fillers found to show agglomerations that led to a decrease in mechanical strength and strain at break. Elastic and secant modulus showed an increasing trend. Contact angle measurements were carried out to determine the oleophilic character of the samples. An increase in the vermiculite content resulted in higher oleophilic character and the lowest contact angle was obtained at 15 wt% VMT loading. In addition to these, thermal stability, thermal dimensional stability and flame retardancy were improved by the incorporation of VMT. 15 wt% vermiculite-filled sample showed the best performance in terms of thermal stability and flame retardancy.

scholarly journals Synthesis, thermal stability, and flame retardancy of PA66, treated with dichlorophenylphsophine derivatives

2016 ◽  
Vol 19 (5) ◽  
pp. 420-428 ◽  
Author(s):  
Wenyan Lyu ◽  
Yihua Cui ◽  
Xujie Zhang ◽  
Jingyao Yuan ◽  
Wei Zhang
Keyword(s):  
Thermal Stability ◽  
Flame Retardancy
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