The Effect of Pre-Crosslinked CTBN on the Mechanical Properties and Morphology of Epoxy Resin

2015 ◽  
Vol 1120-1121 ◽  
pp. 568-571
Author(s):  
Xiao Xue Song ◽  
Shiai Xu

A novel kind of rubber toughened epoxy was prepared by in situ pre-crosslinking carboxyl-terminated butadiene-acrylonitrile copolymer (CTBN) in the epoxy matrix. The in situ pre-crosslinking of CTBN was initiated by BPO, followed by the curing reaction of epoxy to form the final pre-crosslinked CTBN/epoxy composites. Mechanical properties of epoxy are further improved by the incorporation of pre-crosslinked CTBN compared with its traditional CTBN/epoxy counterparts due to the improved interfacial strength between rubber and epoxy. SEM shows that the size of phase separated rubber particles of pre-crosslinked CTBN/epoxy decreases significantly.

2011 ◽  
Vol 287-290 ◽  
pp. 197-200
Author(s):  
Hai Qing Hu ◽  
Li Zhao ◽  
Jia Qiang Liu ◽  
Shi Bao Wen ◽  
Yong Jiang Gu ◽  
...  

Carbon fiber powder (CFP) instead of the traditional glass fiber (cloth) was used to reinforce epoxy resin for rapid tooling. There are two obvious advantages: one is to utilize the waste materials, which is good for the protection of the environment; another is to simplify the producing process by cast molding. The filling amount and dispersing process of CFP was studied in this paper. The results show that when the amount of CFP was 10 wt%, and the ultrasonic time is more than 15 min, the CFP can be dispersed in the epoxy matrix uniformly, and the mechanical properties can meet the requirement of epoxy molding.


2018 ◽  
Vol 9 (1) ◽  
pp. 1-22
Author(s):  
C. Karikal Chozhan ◽  
A. Chandramohan ◽  
M. Alagar

The silicon-containing epoxy/clay nanocomposites were developed by incorporating the surface-modified MMT clay upto 7wt% into Si-epoxy resin. The surface of the montmorillonite (MMT) clay was modified with two surface modifiers namely cetyltrimethylammonium bromide (CTAB) and 3-aminopropyltriethoxysilane (γ-APS). The surface modified clay reinforced Si-epoxy composites were developed in the form of castings, and were characterized for their thermal and mechanical properties. Thermal behaviour of the composites was characterized by differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Mechanical properties were studied as per ASTM standards. Data result from the different studies, it is inferred that the surface modified clay reinforced Si-epoxy composites exhibit lower Tg than that of neat epoxy matrix (127°C <165°C). The decomposition temperature for 60% weight loss of clay reinforced Si-epoxy composites is 674–823°C which is higher when compared to that of neat epoxy matrix. For 5wt% clay reinforced Si-epoxy composites, the values of tensile, flexural and impact strength are increased to 26%, 21% and 29% respectively. The storage modulus (E’) is increased from 5932 to 6308 MPa for clay reinforced Si-epoxy resin. XRD analysis confirmed the well-dispersed exfoliated nanocomposites structure.


Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.


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.


2019 ◽  
Vol 36 (1) ◽  
pp. 47-62
Author(s):  
AR Mohammed ◽  
MS Nurul Atiqah ◽  
Deepu A Gopakumar ◽  
MR Fazita ◽  
Samsul Rizal ◽  
...  

Natural fiber-reinforced composites gained considerable interest in the scientific community due to their eco-friendly nature, cost-effective, and excellent mechanical properties. Here, we reported a chemical modification of kenaf fiber using propionic anhydride to enhance the compatibility with the epoxy matrix. The incorporation of the modified woven and nonwoven kenaf fibers into the epoxy matrix resulted in the improvement of the thermal and mechanical properties of the composite. The thermal stability of the epoxy composites was enhanced from 403°C to 677°C by incorporating modified woven kenaf fibers into the epoxy matrix. The modified and unmodified woven kenaf fiber-reinforced epoxy composites had a tensile strength of 64.11 and 58.82 MPa, respectively. The modified woven composites had highest flexural strength, which was 89.4 MPa, whereas, for unmodified composites, it was 86.8 MPa. The modified woven fiber-reinforced epoxy composites showed the highest value of flexural modulus, which was 6.0 GPa compared to unmodified woven composites (5.51 GPa). The impact strength of the epoxy composites was enhanced to 9.43 kJ m−2 by the incarnation of modified woven kenaf fibers into epoxy matrix. This study will be an effective platform to design the chemical modification strategy on natural fibers for enhancing the compatibility toward the hydrophobic polymer matrices.


2011 ◽  
Vol 194-196 ◽  
pp. 1607-1610
Author(s):  
Yan Yan Lu ◽  
Hua Li ◽  
He Zhou Liu

In this study, we prepared the 3-aminopropyltriethoxysilane (APTES) functionalized MWNTs/epoxy composites by electron beam (EB) irradiation process. The modified MWNTs were characterized with SEM-EDS and FTIR. The gel content and conversion rate of epoxide groups of the EB cured pure epoxy resin and the APTES functionalized MWNTs/epoxy composites were measured and discussed. And the mechanical properties of the EB cured composites were also characterized. With addition of 0.25wt% APTES functionalized MWNTs, the Vicker’s hardness of the EB cured composite increased 100.02% compared with pure epoxy.


2009 ◽  
Vol 79-82 ◽  
pp. 553-556 ◽  
Author(s):  
Ling Fei Shi ◽  
Gang Li ◽  
Gang Sui ◽  
Xiao Ping Yang

The increasing proliferation and application of advanced polymer composites requires higher and broader performance resin matrices. Poly(oxypropylene) with –NH2 end-groups has been widely used to toughen epoxy resins, but the strength of resin matrix may be reduced due to the addition of flexible segments in the crosslinking network. Carbon nanotubes (CNTs) have been paid more and more attention in recent years because of their superior thermal and mechanical properties. In this paper, CNTs grafted with Jeffamines T403 were used to simultaneously improve the reinforcement and toughening of an epoxy resin. The untreated multi-walled carbon nanotubes (u-MWNTs) were functionalized with amine groups according to three steps: carboxylation, acylation, and amidation. The f-MWNTs were characterized by Fourier transform infra-red (FTIR) and X-ray photoelectron spectroscopy (XPS). The experimental results indicated that the T403 was grafted to the surface of MWCNTs. The mechanical and thermal properties of epoxy with f-MWNTs were investigated. The tensile and flexural strength increased by 7.77 % and 7.03 % after adding 0.5wt% f-MWCNTs without sacrificing the impact toughness. At the same time, dynamic mechanical thermal analysis (DMTA) showed that the glass transition temperature (Tg) of epoxy with f-MWNTs were increased. The fracture surface of epoxy with f-MWNTs was observed by scanning electron microscopy (SEM) to understand the dispersion of f-MWNTs in epoxy matrix and interfacial adhesion between f-MWNTs and epoxy matrix, which can be attributed to the strong interfacial bonding between f-MWNTs and epoxy resin.


2020 ◽  
Vol 4 (3) ◽  
pp. 110
Author(s):  
Sujan Debnath ◽  
Tan Ke Khieng ◽  
Mahmood Anwar ◽  
Animesh Kumar Basak ◽  
Alokesh Pramanik

Viscoelastic materials, such as natural fibre-reinforced polymer composites, are strain rate sensitive. In the present investigation, the low strain rate sensitivity (0.00028 s−1, 0.00085 s−1 and 0.0017 s−1) of different sized bagasse particle-reinforced (212 µm and 300 µm) epoxy composites was examined using the Weibull analysis method. The filler loading content was optimized at 2 wt.% to achieve better mechanical properties. Based on the experimental results, it was observed that composites with 212 µm filler particles had higher characteristic strengths, more consistent failure strengths and higher energy absorption properties with higher loading speeds, compared to that of 300 µm filler particles. Based on the mathematical models for particle–matrix interactions, improvements in mechanical properties are attributed to proper filler dispersion and a better fibre–matrix interfacial strength.


2016 ◽  
Vol 217 (9) ◽  
pp. 1065-1073 ◽  
Author(s):  
Jiaotong Sun ◽  
Hui Li ◽  
Cun Wang ◽  
Du Yuan ◽  
Ludger P. Stubbs ◽  
...  

2015 ◽  
Vol 44 (1) ◽  
pp. 19-25
Author(s):  
T. Maity ◽  
B.C. Samanta

Purpose – The purpose of this paper was to check effectiveness of amine functional chloroaniline acetaldehyde condensate (AFCAC) as a new curing agent for diglycidyl ether of bisphenol A (DGEBA) resin. For this purpose, first AFCAC was synthesised, characterised and then curing reaction was carried out. Design/methodology/approach – Equimolecular mixture of AFCAC and DGEBA was subjected to curing reaction, and the reaction was followed by differential scanning calorimetry (DSC) analysis. The kinetic studies of this curing reaction were also carried out from those DSC exotherms. The mechanical properties, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) of cured epoxy were also reported. Findings – DSC results reflected the effective first order curing reaction of AFCAC with epoxy resin. Mechanical properties reflected appreciable rigidity of AFCAC cured epoxy matrix and TGA showed that the cured epoxy networks were thermally stable up to around 297°C. Research limitations/implications – The curing agent AFCAC was synthesised by using chloroaniline and acetaldehyde in acid medium. There are some limitations for this procedure. The synthetic procedure is pH dependent. So reaction cannot be done at any pH value. The reaction must also be carried out at room temperature without any heating. To obtain low molecular weight curing agent, chloroaniline and acetaldehyde cannot be taken in equimolecular ratio because the equimolecular mixture of them produces high molecular weight condensate. This was shown in our previous publication. Some implications are also there. By changing amine and aldehyde other curing agents could be synthesised and the curing efficiency of those for epoxy resin could also be studied. Originality/value – Experimental results revealed the greater suitability of AFCAC as curing agent for DGEBA resin and novelty of AFCAC cured matrix in the field of protective coating, casting, adhesives, etc.


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