Time-Temperature Dependences of Fracture Toughnesses of Epoxy Resin and Silica Particulate-Filled Epoxy Composite

2003 ◽  
Vol 426-432 ◽  
pp. 1985-1990 ◽  
Author(s):  
Wakako Araki ◽  
Tadaharu Adachi ◽  
Akihiko Yamaji
Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2451
Author(s):  
Jianwen Zhang ◽  
Dongwei Wang ◽  
Lujia Wang ◽  
Wanwan Zuo ◽  
Lijun Zhou ◽  
...  

To study the effect of hyperbranched polyester with different kinds of terminal groups on the thermomechanical and dielectric properties of silica–epoxy resin composite, a molecular dynamics simulation method was utilized. Pure epoxy resin and four groups of silica–epoxy resin composites were established, where the silica surface was hydrogenated, grafted with silane coupling agents, and grafted with hyperbranched polyester with terminal carboxyl and terminal hydroxyl, respectively. Then the thermal conductivity, glass transition temperature, elastic modulus, dielectric constant, free volume fraction, mean square displacement, hydrogen bonds, and binding energy of the five models were calculated. The results showed that the hyperbranched polyester significantly improved the thermomechanical and dielectric properties of the silica–epoxy composites compared with other surface treatments, and the terminal groups had an obvious effect on the enhancement effect. Among them, epoxy composite modified by the hyperbranched polyester with terminal carboxy exhibited the best thermomechanical properties and lowest dielectric constant. Our analysis of the microstructure found that the two systems grafted with hyperbranched polyester had a smaller free volume fraction (FFV) and mean square displacement (MSD), and the larger number of hydrogen bonds and greater binding energy, indicating that weaker strength of molecular segments motion and stronger interfacial bonding between silica and epoxy resin matrix were the reasons for the enhancement of the thermomechanical and dielectric properties.


2007 ◽  
Vol 546-549 ◽  
pp. 1581-1584 ◽  
Author(s):  
Jiu Peng Zhao ◽  
Deng Teng Ge ◽  
Sai Lei Zhang ◽  
Xi Long Wei

Silica aerogel/epoxy composite, a kind of efficient thermal insulation material, was prepared by doping silica aerogel of different sizes into epoxy resin through thermocuring process. The results of thermal experiments showed that silica aerogel/epoxy composite had a lower thermal conductivity (0.105W/(m·k) at 60 wt% silica aerogel) and higher serviceability temperature (Martens heat distortion temperature: 160°C at 20 wt% silica aerogel). In addition, the composite doping larger size (0.2-2mm) of silica aerogel particle had lower thermal conductivity and higher Martens heat distortion temperature. Based on the results of SEM and FT-IR, the thermal transfer model was established. Thermal transfer mechanism and the reasons of higher Martens heat distortion temperature have been discussed respectively.


2020 ◽  
Vol 15 (4) ◽  
Author(s):  
Durgaprasad Kollipara ◽  
Prabhakar Gope VNB ◽  
Raja Loya

Composites have tremendous applicability due to their excellent capabilities. The performance of composites mainly depends on the reinforcing material applied. A Graphene nanoparticle (GNP) is successful as an efficient reinforcing material due to its versatile as well as superior properties. Even at very low content, graphene can dramatically improve the properties of polymer and metal matrix composites. In this paper the effects of GNP on composites based on epoxy resin were analyzed. Different contents of GNP (0 – 4.5 vol. %) were added to the epoxy resin. The GNP/epoxy composite was fabricated under room temperature. Mechanical tests result such as tensile, flexural and hardness test show enhancements of the mechanical properties of the GNP/epoxy composite. The experimental results clearly show an improvement in Young’s modulus, tensile strength, and hardness as compared to pure epoxy. The results of this research are strong evidence for GNP/epoxy composites being a potential candidate for use in a variety of industrial applications, especially for automobile parts, aircraft components, and electronic parts such as super capacitors, transistors, etc.


RSC Advances ◽  
2020 ◽  
Vol 10 (55) ◽  
pp. 33576-33584
Author(s):  
Xuefeng Yan ◽  
Leilei Wu ◽  
Shanshan Jin ◽  
Wei Zhao ◽  
Haijian Cao ◽  
...  

Inorganic powders, SiO2 and Al2O3, were used as reinforcements and thermosetting epoxy resin was utilized as a matrix to manufacture IP/epoxy preform, which was coated on the surfaces of 2/1 twill woven polyethylene terephthalate fabrics before the final curing process.


2010 ◽  
Vol 447-448 ◽  
pp. 614-618 ◽  
Author(s):  
Hendra Suherman ◽  
Jaafar Sahari ◽  
Abu Bakar Sulong

This study investigates the electrical conductivity and micro hardness of synthetic and natural graphite epoxy composite. Graphite used on this study is synthetic graphite (SG) and natural graphite (NG) with particle size 44m and 30m, respectively. Different graphite concentrations (50 ~ 80 wt.%) were added into the epoxy resin. The dispersion of graphite in epoxy resin was conducted by high speed mixer through mechanical shearing mechanism, its graphite epoxy suspension was poured into the mold and compression molding was conducted for fabrication of graphite epoxy composites. Electrical conductivity was measured by the four point probe. Microscopic analyses conducted on fracture surface use scanning electron microscopic. Results reveal that non conductive epoxy polymer becomes conductor as addition of graphite. Electrical conductivity of NG higher than SG at the same weight percentage (Wt. %) of conducting filler loading. The highest loading concentration, it exhibited values 12.6 S/cm and 7 S/cm at (80 Wt. %). Hardness property of epoxy composites of both type of graphite increase continuously and reached peak at 60 wt% for NG and 70 wt % for SG, while more addition decreased it.


1990 ◽  
Vol 5 (5) ◽  
pp. 913-915 ◽  
Author(s):  
Manfred Weller ◽  
Hassel Ledbetter

Using a computer-controlled inverted torsion pendulum at frequencies near 1 Hz, we determined the mechanical losses in a uniaxially fiber-reinforced composite. The composite comprised glass fibers in an epoxy-resin matrix. We studied three fiber contents: 0,41, and 49 vol.%. Three mechanical-loss peaks appeared: above 300 K, near 200 K, and near 130 K. They correspond closely to α, β, and γ peaks found previously in many polymers. We failed to see a mechanical-loss peak for either the glass or the glass-resin interface. Between 300 and 4 K, the torsion modulus increased in the resin by a factor of 3.30 and in the 0.49 glass-epoxy by a factor of 2.37.


Fibers ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 4 ◽  
Author(s):  
Widayani Sutrisno ◽  
Mitra Rahayu ◽  
Damar Rastri Adhika

The aim of this study is to analyze the thermal properties of sago fiber-epoxy composite. The sago fiber-based composite has been prepared using epoxy resin as the matrix, via a simple mixing followed by compression. The compression process includes hot compression (100 °C/10 kgf cm−2) and cold compression (ambient/10 kgf cm−2). The composite series was prepared with 9%, 13%, 17%, 20%, and 23% (w/w) of epoxy resin. Microstructures of all materials used were observed using an SEM (scanning electron microscope) instrument. The thermal properties of the composite and its components were examined through TG/DTA characterization. The samples were heated using the heating rate of 10 °C/min from room temperature to 400 °C, except for epoxy resin, which was heated to 530 °C. TG/DTA results depict three stages of thermal processes of sago fiber-epoxy composite: evaporation of water molecules at below 100 °C with the peak point within the range of 51.3 and 57.3 °C, the damage of sago fiber within the range of 275 and 370 °C with the peak point within the range of 333.3 and 341.3 °C and the damage of epoxy resin at above 350 °C with the peak point at 376.2 °C.


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