Abstract:Phenolic resin/clay composites were prepared by high‐shear mixing of clay suspended in CH3OH solutions of Novolac resin and curing agent. Pure clay Cloisite Na+ and pillared clays Cloisite 10A, 30B, and Na+Cloisite that was pillared by 3‐hexadecyl‐1‐methylimidazolium bromide were studied. After CH3OH evaporation, Novolac was cured at low temperatures. XRD showed that clay gallery d‐spacings decreased upon solvent evaporation and partial curing. Slight d‐spacing increases were sometimes observed from a partiall… Show more
“…Among these polymers, phenolic resins (PRs) play an important role in aerospace application owing to their low cost, dimensional stability, chemical resistance and excellent ablative property . However, the disadvantages of PRs, such as their inherent brittleness, large volumetric shrinkage during curing and low char yield, greatly restrict their application and point to a need for modification . Extensive research has been carried out to improve the properties of PRs such as copolymerization, blending, the use of elastomers, the introduction of functional groups with high carbon content and the addition of heteroatoms and nanocomposites .…”
“…Among these polymers, phenolic resins (PRs) play an important role in aerospace application owing to their low cost, dimensional stability, chemical resistance and excellent ablative property . However, the disadvantages of PRs, such as their inherent brittleness, large volumetric shrinkage during curing and low char yield, greatly restrict their application and point to a need for modification . Extensive research has been carried out to improve the properties of PRs such as copolymerization, blending, the use of elastomers, the introduction of functional groups with high carbon content and the addition of heteroatoms and nanocomposites .…”
“…The distance between the molecules of novolac resin and silica particles is the result of thermodynamic dependence of matrix and silicate layer. 23,24,3 Figure 3.X-ray spectrum of Nano-silica composite with 1% and 3% weight percentage.Figure 4.X-ray spectrum of Nano-clay composite with 1% and 3% weight percentage.…”
The mechanical properties of phenol formaldehyde (phenolic novolac) and short carbon fiber T300 polymer-based nano-composites-reinforced with nano-silica and nano-clay particles have been studied experimentally. By increasing the weight percentage of the short carbon fiber in the phenol formaldehyde, the strength of the composite increases, but its plastic deformation is severely limited. Also, in the case of composite reinforced with nano-silica particles, the tensile and flexural strength of the composite with the increase in the weight percentage of the nano-silica increase by 1% to 3%, whereas with the nano-clay particles, the tensile and flexural strength of the composite decrease by 1% to 3%. It is composite with 1% weight percentage of the nano-clay particle which has the highest strength in comparison to the other samples. Regardless of the type of corrosive solution, the composite strength decreases significantly over 25 days. However, with an increase in the duration from 25 days to 45 days, a slight change has been observed. The outcomes indicate that the corrosion of PF/CF40% composites and the composite reinforced with silica nanoparticles are higher corrosion rate in acid than in salt solution. In contrast, the nano-clay composite has more corrosion in salt solution. Furthermore, the analysis of the fracture surface of samples done by SEM microscopy shows reduction of the porosity in the case of using nanoparticles.
“…Although due to the long alkyl side chains of cardanol, the thermal stability of nanocomposites was rather low, incorporation of nanoclay helps to overcome this problem. Zhang et al prepared novolac phenolic resin/clay composites by high‐shear mixing, which were utilized in high temperature applications. The presence of nanoclay greatly increased high temperature erosion resistance of phenolic resins.…”
Cloisite 30B as a modified kind of nanoclay was utilized for the formation of 3D network based on novolac resin with high thermal stable properties. Two types of phenolic resins including neat novolac (NR) and modified novolac resin were used to create a compatible matrix with nanoclay. For this purpose, NR modified with (3chloropropyl)triethoxysilane (CPTES) to form SiNR. For improvement of thermal behaviors, Cloisite 30B was dispersed in matrix via ultrasonic waves and cured with hexamethylenetetramine (HMTA) to form 3D network. X-ray diffraction (XRD) analysis was used to measure the d-spacing in intercalated systems and results indicated the optimum amount of clay for appropriate thermal properties. Investigation of the thermal properties of the samples by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the presence of Cloisite 30B in matrix resulted in much higher thermal stability and char yield with respect to modification of novolac resin originated from formation of 3D Si-O-Si network. Also, cured modified resin and its nanocomposites showed much higher thermal stability than cured NR and its nanocomposites. Such nanocomposite materials with high thermal stability have potential applications in advanced fields such electronic, industrial molds, coatings, adhesives, and aerospace composites.
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