AO-resistant shape memory polyimide/silica composites with excellent thermal stability and mechanical properties

RSC Advances ◽  
2015 ◽  
Vol 5 (89) ◽  
pp. 72971-72980 ◽  
Author(s):  
Zenghui Yang ◽  
Qihua Wang ◽  
Yongkang Bai ◽  
Tingmei Wang
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Shape Memory ◽  
Composite Films ◽  
Excellent Thermal Stability ◽  
Good Thermal Stability ◽  
Silica Composite

Shape memory polyimide/silica composite films show AO-resistant performance, good thermal stability and mechanical properties.

Effect of Long-Term Aging on Microstructure and Mechanical Properties of a Wrought Ni-Base Superalloy

2015 ◽  
Vol 816 ◽  
pp. 546-550
Author(s):  
Chao Yuan ◽  
Huan Wang ◽  
Jian Ting Guo ◽  
He Yong Qin
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Room Temperature ◽  
Excellent Thermal Stability ◽  
Good Thermal Stability ◽  
Increasing Trend ◽  
Size And Morphology ◽  
Strength And Plasticity ◽  
Base Superalloy

During long-term and high temperature service, microstructures of superalloys may change and then have an adverse impact on mechanical properties, so the stabilities of a wrought Ni-base superalloy aging without stress at 650°C were investigated in this paper. The results showed that the size and morphology of γ' precipitates in the alloy were not obviously influenced with the increase of exposure time, and primary MC carbides present excellent thermal stability. Moreover, almost no detrimental phase was found. Tensile strength and plasticity at room temperature after aging remained steady. Under the condition of 650°C/823MPa, the stress ruptures life presented increasing trend overall and plasticity decreases slightly. In conclusion, the experiment alloy presents a good thermal stability at 650°C.

Preparation and Properties of Polyimide/MWNTs-COOH Antistatic Composites

2014 ◽  
Vol 893 ◽  
pp. 241-244
Author(s):  
Yong Hui Lv ◽  
Bao Xiang Deng
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Acid Treatment ◽  
In Situ Polymerization ◽  
Composite Films ◽  
Good Thermal Stability ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The acidified multi-walled carbon nanotubes (MWNTs-COOH) was obtained by nitric acid treatment on multi-walled carbon nanotubes (MWNTs).The PI/MWNTs-COOH composite films were synthesized by in situ polymerization. The thermal stability, resistance and mechanical properties of PI/MWNTs-COOH composite were evaluated. The results showed that: the composites maintained a good thermal stability with the addition of the MWNTs-COOH; the resistance of the composite film dropped at first, and rose up later. While the tensile strength increased at first and then decreased. In conclusion, the PI/MWNTs-COOH composite films exhibited better thermal, antistatic and mechanical properties compared with neat PI.

scholarly journals Preparation and Characterization of Transparent Polyimide–Silica Composite Films Using Polyimide with Carboxylic Acid Groups

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 489 ◽  
Author(s):  
Kwan Moon ◽  
Boknam Chae ◽  
Ki Kim ◽  
Seung Lee ◽  
Young Jung
Keyword(s):  
Thermal Stability ◽  
Carboxylic Acid ◽  
Coefficient Of Thermal Expansion ◽  
Condensation Reaction ◽  
Sol Gel ◽  
Composite Films ◽  
Amic Acid ◽  
Good Thermal Stability ◽  
Silica Composite ◽  
Sol Gel Process

Polyimide (PI) composite films with thicknesses of approximately 100 µm were prepared via a sol–gel reaction of 3-aminopropyltrimethoxysilane (APTMS) with poly(amic acid) (PAA) composite solutions using a thermal imidization process. PAA was synthesized by a conventional condensation reaction of two diamines, 3,5-diaminobenzoic acid (DABA), which has a carboxylic acid side group, and 2,2′-bis(trifluoromethyl)benzidine (TFMB), with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) in N,N-dimethylacetamide (DMAc). The PAA–silica composite solutions were prepared by mixing PAA with carboxylic acid side groups and various amounts of APTMS in a sol–gel process in DMAc using hydrochloric acid as a catalyst. The obtained PI–silica composite films showed relatively good thermal stability, and the thermal stability increased with increasing APTMS content. The optical properties and in-plane coefficient of thermal expansion (CTE) values of the PI–silica composite films were investigated. The CTE of the PI–silica composite films changed from 52.0 to 42.1 ppm/°C as the initial content of APTMS varied. The haze values and yellowness indices of the composite films increased as a function of the APTMS content.

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.

Effect of Heat Treatment on Mechanical Properties of ECAPed 7075 Aluminum Alloy

2013 ◽  
Vol 829 ◽  
pp. 62-66 ◽  
Author(s):  
Alireza Fallahi ◽  
Hossein Hosseini-Toudeshky ◽  
Seyed Mahmoud Ghalehbandi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Alloy ◽  
Solution Treatment ◽  
7075 Aluminum Alloy ◽  
Ecap Processing ◽  
Good Thermal Stability ◽  
7075 Alloy

It is the objective of this study to investigate the effect of ECAP processing and heat treatment on the mechanical properties of the UFG 7075 alloy. Also the effect of post ECAP heat treatment is investigated. The alloy is processed by ECAP after annealing as well as solution treatment to produce an UFG structure. Furthermore mechanical properties and their variations during annealing and aging are investigated. The hardness of the pre-ECAP annealed and the pre-ECAP solutionised 7075 aluminum alloy has increased significantly compared with that of the CG sample. Also hardness of ECAPed specimen has not experienced significant changes in post-ECAP heat treatment and indicated that the alloy had approximately good thermal stability.

Semi-bio-based aromatic polyamides from 2,5-furandicarboxylic acid: toward high-performance polymers from renewable resources

RSC Advances ◽  
2016 ◽  
Vol 6 (90) ◽  
pp. 87013-87020 ◽  
Author(s):  
Kaiju Luo ◽  
Yan Wang ◽  
Junrong Yu ◽  
Jing Zhu ◽  
Zuming Hu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Renewable Resources ◽  
High Performance ◽  
Good Thermal Stability ◽  
Aromatic Polyamides ◽  
High Performance Polymers ◽  
Furandicarboxylic Acid

Aromatic furanic polyamides with relatively high molecular weight were synthesized, and good thermal stability and mechanical properties were demonstrated.

Thermal Stability of Solid Aluminum Electrolytic Capacitors with Conductive Polyaniline Counter Electrode

2012 ◽  
Vol 512-515 ◽  
pp. 1018-1021
Author(s):  
Xu Fei Zhu ◽  
Long Fei Jiang ◽  
Wei Xing Qi ◽  
Chao Lu ◽  
Ye Song
Keyword(s):  
Thermal Stability ◽  
Counter Electrode ◽  
Electrolytic Capacitor ◽  
Aluminum Electrolytic Capacitor ◽  
Dodecylbenzenesulfonic Acid ◽  
Excellent Thermal Stability ◽  
High Frequencies ◽  
Solid Aluminum ◽  
Good Thermal Stability ◽  
Thermal Stability Of

To overcome the risk of electrolyte leakage and the shortcoming of higher impedance at high frequencies for the conventional aluminum electrolytic capacitor impregnated with electrolyte solutions, solid aluminum electrolytic capacitor employing conducting polyaniline (PANI) as a counter electrode was developed. The as-fabricated solid capacitors have very low impedances at high frequencies and excellent thermal stability. The superior performances can be ascribed to high conductivity and good thermal stability of the camphorsulfonic acid (CSA)-dodecylbenzenesulfonic acid (DBSA) co-doped PANI.

scholarly journals Phase Formation, Thermal Stability and Mechanical Properties of a Cu-Al-Ni-Mn Shape Memory Alloy Prepared by Selective Laser Melting

2015 ◽  
Vol 18 (suppl 2) ◽  
pp. 35-38 ◽  
Author(s):  
Piter Gargarella ◽  
Cláudio Shyinti Kiminami ◽  
Eric Marchezini Mazzer ◽  
Régis Daniel Cava ◽  
Leonardo Albuquerque Basilio ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Phase Formation ◽  
Laser Melting

Fabrication of Composite Films Based on Chitosan and Vegetable-Tanned Collagen Fibers Crosslinked with Genipin

2021 ◽  
Vol 116 (10) ◽  
Author(s):  
Jie Liu ◽  
Yanchun Liu ◽  
Eleanor M. Brown ◽  
Zhengxin Ma ◽  
Cheng-Kung Liu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Water Vapor ◽  
Composite Film ◽  
Composite Films ◽  
Value Added ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Leather Industry ◽  
Compact Structure

The leather industry generates considerable amounts of solid waste and raises many environmental concerns during its disposal. The presence of collagen in these wastes provides a potential protein source for the fabrication of bio-based value-added products. Herein, a novel composite film was fabricated by incorporating vegetable-tanned collagen fiber (VCF), a mechanically ground powder-like leather waste, into a chitosan matrix and crosslinked with genipin. The obtained composite film showed a compact structure and the hydrogen bonding interactions were confirmed by FTIR analysis, indicating a good compatibility between chitosan and VCF. The optical properties, water absorption capacity, thermal stability, water vapor permeability and mechanical properties of the composite films were characterized. The incorporation of VCF into chitosan led to significant decreases in opacity and solubility of the films. At the same time, the mechanical properties, water vapor permeability and thermal stability of the films were improved. The composite film exhibited antibacterial activity against food-borne pathogens. Results from this research indicated the potential of the genipin-crosslinked chitosan/VCF composites for applications in antimicrobial packaging. 

Design and development of HMS@ZIF-8/fluorinated polybenzoxazole composite films with excellent low-k performance, mechanical properties and thermal stability

2020 ◽  
Vol 8 (22) ◽  
pp. 7476-7484 ◽  
Author(s):  
Xudong Zhou ◽  
Xiaoyun Liu ◽  
Zhongkai Cui ◽  
Jinlou Gu ◽  
Shaoliang Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Composite Film ◽  
Composite Films ◽  
Design And Development ◽  
Hollow Silica ◽  
New Type ◽  
Low K

A new-type of hollow silica@ZIF-8 (HMS@ZIF-8) particle was successfully designed, fabricated and introduced into the fluorinated polybenzoxazole (6FPBO) matrix to prepare the HMS@ZIF-8/6FPBO composite film.

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