Abstract:Carboxyl-terminated poly(acrylonitrile-co-butadiene) (CTBN)-grafted epoxidized linseed oil (ELO) (CTBN-g-ELO) was synthesized and used as an effective toughener to simultaneously enhance the mechanical properties and fracture toughness of epoxy resin (EP). The ELO was fabricated from linseed oil via epoxidation processing. The characteristics of the ELO and CTBN-g-ELO, such as the average molecular weight and chemical structure, were determined using gel permeation chromatography, proton nuclear magnetic reson… Show more
“…The increase in toughness of epoxy-based composites with the use of fillers is justified by the presence of obstacles (i.e., particle bridging), which alters crack orientation and growth and, consequently, hinders its propagation. 42,43 This effect is more pronounced when the reinforcement shows good anchoring to the matrix, which also modifies the failure pattern. 44…”
Section: Resultsmentioning
confidence: 99%
“…Addition of MCC, modified or not, did not influence dispersion of rubber phase in epoxy. Some spheres on the surface (Figure 5(c), (f), and (h)) represent a heterogeneous epoxy system, 43 characteristic of the liquid rubber/epoxy phase separation. 37,46 Figure 5.SEM micrographs of the crack’s initiation on the surface for neat epoxy (a, b), e/10NBR (c, d), e/10NBR-MCC (e, f), e/10NBR-MCC-Si (g, h).…”
Section: Resultsmentioning
confidence: 99%
“…Addition of MCC, modified or not, did not influence dispersion of rubber phase in epoxy. Some spheres on the surface (Figure 5(c), (f), and (h)) represent a heterogeneous epoxy system, 43 characteristic of the liquid rubber/epoxy phase separation. 37,46 The phase separation of liquid rubber and epoxy resin is characterized by the formation of rubber domains (round shape) dispersed in the matrix 47 and the properties of the resultant epoxy/rubber system depend on the final morphology.…”
Toughening epoxy resins by adding different agents has been employed as a way to reduce brittleness in composites. Some hybridization strategies combining liquid rubbers and rigid fillers can be found in the literature, but the pair cellulose-based reinforcement, such as microcrystalline cellulose (MCC), and liquid acrylonitrile butadiene rubber (NBR) is hardly studied. The aim of this work is to investigate the effect of hybridizing MCC and amino-functionalized MCC (MCCSi) with NBR on the thermal, mechanical, and dynamic-mechanical behavior of epoxy. X-ray microtomography showed a good dispersion of MCCSi fillers in epoxy/NBR compared to the non-treated MCC filler. NBR with MCCSi was found to slightly increase the thermal stability of epoxy. The addition of MCC, regardless of the functionalization, decreased tensile strength and elastic modulus, but improved impact strength and toughness properties (KIC). Also, MCCSi composites displayed better dynamic-mechanical behavior, attributed to the enhanced chemical interaction, with a small effect on glass transition temperature.
“…The increase in toughness of epoxy-based composites with the use of fillers is justified by the presence of obstacles (i.e., particle bridging), which alters crack orientation and growth and, consequently, hinders its propagation. 42,43 This effect is more pronounced when the reinforcement shows good anchoring to the matrix, which also modifies the failure pattern. 44…”
Section: Resultsmentioning
confidence: 99%
“…Addition of MCC, modified or not, did not influence dispersion of rubber phase in epoxy. Some spheres on the surface (Figure 5(c), (f), and (h)) represent a heterogeneous epoxy system, 43 characteristic of the liquid rubber/epoxy phase separation. 37,46 Figure 5.SEM micrographs of the crack’s initiation on the surface for neat epoxy (a, b), e/10NBR (c, d), e/10NBR-MCC (e, f), e/10NBR-MCC-Si (g, h).…”
Section: Resultsmentioning
confidence: 99%
“…Addition of MCC, modified or not, did not influence dispersion of rubber phase in epoxy. Some spheres on the surface (Figure 5(c), (f), and (h)) represent a heterogeneous epoxy system, 43 characteristic of the liquid rubber/epoxy phase separation. 37,46 The phase separation of liquid rubber and epoxy resin is characterized by the formation of rubber domains (round shape) dispersed in the matrix 47 and the properties of the resultant epoxy/rubber system depend on the final morphology.…”
Toughening epoxy resins by adding different agents has been employed as a way to reduce brittleness in composites. Some hybridization strategies combining liquid rubbers and rigid fillers can be found in the literature, but the pair cellulose-based reinforcement, such as microcrystalline cellulose (MCC), and liquid acrylonitrile butadiene rubber (NBR) is hardly studied. The aim of this work is to investigate the effect of hybridizing MCC and amino-functionalized MCC (MCCSi) with NBR on the thermal, mechanical, and dynamic-mechanical behavior of epoxy. X-ray microtomography showed a good dispersion of MCCSi fillers in epoxy/NBR compared to the non-treated MCC filler. NBR with MCCSi was found to slightly increase the thermal stability of epoxy. The addition of MCC, regardless of the functionalization, decreased tensile strength and elastic modulus, but improved impact strength and toughness properties (KIC). Also, MCCSi composites displayed better dynamic-mechanical behavior, attributed to the enhanced chemical interaction, with a small effect on glass transition temperature.
“…Despite significant advances achieved in the exploration of BFRPs and their composites by far, the major bottleneck for the large-scale utilization of BFRPs lies in their poor stability in alkaline corrosive environments. , Debonding and degradation occur at the matrix and the interface between the fiber and the matrix, resulting in a significant decrease in mechanical properties. The pursuit of high-performance matrixes is of paramount significance to realize FRPs with superior mechanical properties and long-term stabiliy. , In this respect, massive efforts have been devoted to incorporating organic/inorganic fillers into polymer matrixes. − …”
Fiber-reinforced polymer (FRP) composites have emerged as promising next-generation materials for advanced structures in civil engineering. Notwithstanding the recent progress, the unsatisfactory mechanical properties and problematic long-term stability in the alkali environment remain daunting challenges toward their large-scale practicability. In this study, we address such limitations by a dual modification method, in which first ethyl cellulose (EC) is incorporated into the matrix and then the FRP composite is dipped in a dilute poly(dimethylsiloxane) (PDMS) solution. The FRP composite exhibited enhanced flexural strength by 23.4% and increased flexural modulus by 23.5% compared to those of the pristine basalt fiber-reinforced polymer (BFRP). Such an eminent performance is mainly attributed to the bridging effect of EC. As confirmed by the DMA characterization, the incorporation of EC greatly increased the cross-linking density and improved the thermal stability. Additionally, the FRP composite had a stable performance in the alkali environment tests. Tuning the amount of ethyl cellulose was found to have a profound effect on the mechanical performance and aging behavior in the alkali solution. This study establishes a practical approach to fabricating FRP composites with long-term stability in alkali environments.
“…[13][14][15][16][17][18][19][20] In addition, the high flammability of EP is the main drawback limiting its application in high-performance areas. 21,22 For this reason, improvement of the flame retardancy of EP is needed. Many researchers have attempted to enhance the flame retardancy of EP.…”
The combined effects of phosphorous-jointed epoxidized soybean oil and rice husk–based silica on the flammability and mechanical properties of epoxy resin were examined in detail. The chemical structures of the epoxidized soybean oil, phosphorous-jointed epoxidized soybean oil, and rice husk–based silica were confirmed using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Many characteristics of the obtained composite materials were examined, such as the tensile properties, impact strength, flexural strength, critical stress intensity factor (KIC), dynamic mechanical analysis, and flammability. The incorporation of both 10 phr phosphorous-jointed epoxidized soybean oil and 20 phr rice husk–based silica into the epoxy resin yielded the optimum values of the flexural strength, tensile strength, impact strength, and KIC, with increases of 87.78%, 67.23%, 109.34%, and 111.32%, respectively, compared with pristine samples. The limiting oxygen index increased from 23.1% to 29.3%, the peak heat-release rate decreased by up to 37.2%, and the sample satisfied the UL94 V-0 rating.
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