Coefficient of thermal and moisture expansion and moisture absorption for dimensionally stable quasi-isotropic high-modulus graphite fiber/epoxy composites

Author(s):  
Christopher Blair ◽  
Jerry Zakrzewski
2021 ◽  
Author(s):  
Johannes Essmeister ◽  
M. Josef Taublaender ◽  
Thomas Koch ◽  
D. Alonso Cerrón-Infantes ◽  
Miriam M. Unterlass ◽  
...  

A novel class of fully organic composite materials with well-balanced mechanical properties and improved thermal stability was developed by incorporating highly crystalline, hydrothermally synthesized polyimide microparticles into an epoxy matrix.


2011 ◽  
Vol 217-218 ◽  
pp. 728-733 ◽  
Author(s):  
Yan Hong Tian ◽  
Zhan Qing Liu ◽  
Su Mei Kang ◽  
Xue Jun Zhang

With toluene 2, 4-diisocyanate (TDI), polyethylene glycol (PEG) and 2,3-Epoxy-1-prop -anol (glycidol) used as the raw materials, two epoxy terminated polyurethanes (EPU) was synthesized by prepolymerization and closed end. Moreover, EPU with high toughhess is chosen as a coating agent for carbon fiber with three ethylene tetramine (TETA) as curing agen. The influence of the content of crosslinking agent in the coating layer on properties of composites and the mechanism of interface toughness are investigated. The chemical structure and thermal property of the EPU were studied with FTIR, 1HNMR and TGA, respectively. It proves that the thermal stability of EPU is more stable than epoxy coating. The interlaminar shear strength (ILSS) of the sized high modulus carbon fiber/epoxy composites is improved to 71MPa, which increased by 19.4% compared with the composites reinforced by unsized high modulus carbon fiber, and DMTA show that using EPU as a new kind of polymer coating for carbon fiber is a feasible method to improve the interfacial performance of high modulus carbon fiber/epoxy composites.


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2162
Author(s):  
King Jye Wong ◽  
Mahzan Johar ◽  
Seyed Saeid Rahimian Koloor ◽  
Michal Petrů ◽  
Mohd Nasir Tamin

It is necessary to consider the influence of moisture damage on the interlaminar fracture toughness for composite structures that are used for outdoor applications. However, the studies on the progressive variation of the fracture toughness as a function of moisture content M (%) is rather limited. In this regard, this study focuses on the characterization of mode II delamination of carbon/epoxy composites conditioned at 70 °C/85% relative humidity (RH). End-notched flexure test is conducted for specimens aged at various moisture absorption levels. Experimental results reveal that mode II fracture toughness degrades with the moisture content, with a maximum of 23% decrement. A residual property model is used to predict the variation of the fracture toughness with the moisture content. Through numerical simulations, it is found that the approaches used to estimate the lamina and cohesive properties are suitable to obtain reliable simulation results. In addition, the damage initiation is noticed during the early loading stage; however, the complete damage is only observed when the numerical peak load is achieved. Results from the present research could serve as guidelines to predict the residual properties and simulate the mode II delamination behavior under moisture attack.


2017 ◽  
Vol 51 (28) ◽  
pp. 3909-3922 ◽  
Author(s):  
Priyadarshi Tapas Ranjan Swain ◽  
Sandhyarani Biswas

The present paper discovers the effect of ceramic filler inclusion on physico-mechanical and water absorption behaviour of untreated and chemically treated (alkali and benzoyl chloride treated) bi-directional jute natural-fiber-reinforced epoxy composites. In practice, the major drawbacks of using natural fibers are their high degree of moisture absorption and poor dimensional stability. Currently, chemical treatments are able to induce fiber modifications that increase their resistance when utilized in composite products. Jute fibers were subjected to various chemical modifications to improve the interfacial bonding with the matrix. In this study, an analysis has been carried out to make pre-treated jute fiber (10, 20, 30 and 40 wt.%) and different filler content (5 and 10 wt.%) with epoxy-based composites. A comparative study of all the untreated jute/aluminium oxide based hybrid composites with chemically treated jute/aluminium oxide based hybrid composites was carried out. The investigational result reveals that chemically treated composites considerably improved the mechanical properties of the composite. The maximum water absorption resistance and strength properties were found with benzoyl chloride-treated fiber-reinforced composite. Lastly, the surface morphology of fractured surfaces after tensile and flexural testing is studied using scanning electron microscope.


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