Phenolic foams toughened with crosslinked poly (n‐butyl acrylate)/silica core‐shell nanocomposite particles

Abstract

A new type of crosslinked poly (n‐butyl acrylate) (PBA)/silica core‐shell nanocomposite particles was adopted as toughening agent to improve the mechanical properties of phenolic foams. The effects of the nanocomposite particles on the structures and properties of lightweight phenolic foams were investigated. SEM result showed that the addition of a small quantity of the nanocomposite particles can significantly enhance the structural homogeneity of phenolic foams. Thermalgravimetric analysis result suggested that the incorporation of the nanocomposite particles did not affect the thermal stability of the toughened phenolic foams. The flexural strength, compressive strength, and elastic modulus of the phenolic foams increased distinctively after the addition of the nanocomposite particles, the maximum values of which increased by 36.0%, 42.9%, and 32.3%, respectively. In this study, the optimum dosage of the nanocomposite particles is 0.03 phr in the modified phenolic foams. Moreover, the influence on the flammability of phenolic foams by toughening can almost be neglected. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42590.

Phenolic foams: A review of mechanical properties, fire resistance and new trends in phenol substitution

“…Yang et al [43] observed that the incorporation of 5 wt% of polyurethane foam scraps particles (D = 80 -150 µm) increases the compressive strength by 12 %. The same observations were reported with the addition of 0.05 phr of poly(n-butyl acrylate)/Silica (PBA/Silica) core-shell particles (D = 180 nm) [45], which led to a 45% improvement of the compressive strength.…”

“…Polyethylene glycol sorbitan monooleate, a non-ionic surfactant commercially known as Tween 80 [38,43,45], is mostly used. Silicon oil [46,47] was reported as an alternative to Tween 80.…”

“…Many studies exist in the literature, and most of them focus on particles. In most studies, the decrease of the mean cell size is connected to the increase of the compressive strength [17,33,35,36,41,45,80,81]. The mean cell size is noted as <D cell >.…”

“…Attention also has to be paid to the mixture viscosity because the addition of particles increases it. This can be beneficial for the final microstructure, but if the increase is too high, it can impede the foam expansion [45]. Compared with fibres, the increase in viscosity is less problematic during the mixing stage because the particles have a smaller aspect ratio.…”

Phenolic Resin Foam Composites Reinforced by Acetylated Poplar Fiber with High Mechanical Properties, Low Pulverization Ratio, and Good Thermal Insulation and Flame Retardant Performance

“…Therefore, reinforcement has been an important research direction of phenolic foam composites.In recent years, many researchers have conducted numerous studies on the strengthening of phenolic foam composites. The easiest and most convenient way to enhance phenolic foam is to blend some external toughening agents in phenolic resins, such as natural rubber, nitrile rubber [11][12][13][14], external flexures, and fiber materials, such as glass fiber [15][16][17]. Although the addition of rubber improves the toughness of PF, it reduces its heat resistance [18].…”