Optimization of Epoxy Resin: An Investigation of Eggshell as a Synergic Filler

Abstract

Epoxy resin based on bisphenol A diglycidyl ether/anhydride methyl tetrahydrophthalic/2,4,6-tris(dimethylaminomethyl)phenol (DGEBA/MTHPA/DEH 35) was produced by magnetic stirring; chicken eggshell (ES) was added as cure improver. Thermal stability, cure parameters, mechanical properties, and fracture surface were investigated by thermogravimetry (TGA), differential scanning calorimetry (DSC), tensile experiments, and scanning electron microscopy (SEM). In general, the addition of ES slightly decreased the thermal stability, being T0.05 5% lower than that of the reference sample. The cure rate increased with the heating rates, while best results were obtained upon addition of neat membrane (M) from ES. Surprisingly, the mechanical properties were significantly improved with ES as well as with M, being the Young’s modulus 18% higher, the tensile strength 50% higher, and the deformation 35% higher than those of epoxy resin. SEM images showed that the synthetic compounds presented a smooth fracture surface, while the compounds with ES and M had a rougher surface with multiplane fractures, suggesting a fracture with higher energy absorption. In conclusion, epoxy/ES composites with better performance were produced, and effective tools are provided to control and attain in the future even better properties with ecological features.

Degradation kinetics of epoxidized soybean oil

“…The deconvolution of ESO 87:10 DTG peaks heated at 10°C/min presented three main events, in the temperature ranges T E1 0.01 = 91°C and T E1 0.99 = 416°C, T E2 0.01 = 304°C and T E2 0.99 = 434°C and T E3 0.01 = 398°C and T E3 0.99 = 462°C, respectively. The first event (E1) is characteristic of the decomposition of unreacted DEH 35, MTHPA, and ESO raw materials, and lighter crosslinked network 24 . The second event (E2) with greater intensity is characteristic of the material degradation with wide crosslinking density; it is assumed that structures with networks of different sizes (lighter to densely reticulated) are degraded in this temperature range 25 .…”

“…For a better understanding and justification of the observed events in the plots of Figure 3 24 The second event (E2) with greater intensity is characteristic of the material degradation with wide crosslinking density; it is assumed that structures with networks of different sizes (lighter to densely reticulated) are degraded in this temperature range. 25 The third event (E3) is assumed to be associated with carbon decomposition, initiating degradation at approximately 400 C. 26 In the deconvolutions presented in the Supplementary Material, some compositions displayed four degradation events while in other five events were observed.…”

Tailoring sustainable compounds using eggshell membrane as biobased epoxy catalyst

“…Processing of membrane (M) was performed as an adapted methodology elsewhere proposed [22] . Eggshell was washed in sodium hypochlorite (NaClO) and afterwards immersed in water for 2 h to remove the membrane.…”

Phosphorous-jointed epoxidized soybean oil and rice husk-based silica as the novel additives for improvement mechanical and flame retardant of epoxy resin

“…The morphology was examined using field-emission scanning electron microscopy (SEM) (S-4800, Hitachi, Japan) in which the fracture surfaces were coated with thin gold layer. Differential scanning calorimetry (DSC, PerkinElmer, USA) was used to examine the curing reaction of the uncured EP system at various heating rates (5,10,15, and 20°C/min) in a nitrogen environment. Approximately 6.5 g of the epoxy sample was sealed in an aluminum cup before heating from 25°C to 180°C.…”

“…Thermosetting epoxy resins (EPs) have been widely used as matrices in the fabrication of fiber-filled polymer-based composites owing to their good mechanical properties, high chemical resistance, compatibility with most fibers, processability, and low cost. [5][6][7][8][9][10] However, EPs have a low fracture energy as result of their high crosslinking density after curing. 11,12 This disadvantage limits their application in high-technology areas.…”