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

Abstract

Phenolic foam composites (PFs) are of substantial interest due to their uniform closed-cell structure, low thermal conductivity, and good thermal insulation performance. However, their disadvantages of a high pulverization rate and poor mechanical properties restrict their application in building exterior insulation. Therefore, the toughening of these composites is necessary. In this paper, poplar fiber was treated with an acetylation reagent, and the acetylated fiber was used to prepare modified phenolic foams (FTPFs); this successfully solved the phenomenon of the destruction of the foam structure due to the agglomeration of poplar fiber in the resin substrate. The foam composites were comprehensively evaluated via the characterization of their chemical structures, surface morphologies, mechanical properties, thermal conductivities, and flame retardant properties. It was found that the compressive strength and compressive modulus of FTPF-5% respectively increased by 28.5% and 37.9% as compared with those of PF. The pulverization ratio was reduced by 32.3%, and the thermal insulation performance and flame retardant performance (LOI) were improved. Compared with other toughening methods for phenolic foam composites, the phenolic foam composites modified with surface-compatibilized poplar fiber offer a novel strategy for the value-added utilization of woody fiber, and improve the toughness and industrial viability of phenolic foam.

Thermal degradation, visco-elastic and fire-retardant behavior of hybrid Cyrtostachys Renda/kenaf fiber-reinforced MWCNT-modified phenolic composites

“…Flame dripping has not been detected on any set of hybrid phenolic composite, a char layer developed with less smoke. Similar findings were also reported by [ 47 ]. The development of a char layer on its surface preserves the internal structure [ 48 ].…”

Mesoporous multi-shelled hollow resin nanospheres with ultralow thermal conductivity

“…4c, the thermal conductivity of phenolic resin-based materials ranged from 0.02 W m −1 K −1 to 0.08 W m −1 K −1 . 36–39 Meanwhile for materials based on other polymers such as polyimide, the thermal conductivity ranged from 0.02 W m −1 K −1 to 0.05 W m −1 K −1 . 40–42 In general, few materials could achieve thermal conductivity below 0.02 W m −1 K −1 .…”

A comprehensive review on phenol‐formaldehyde resin‐based composites and foams

“…[ 81 ] The preparation of PF foam includes an emulsifier, blowing agent, catalyst, curing agents, and some additives. The additives can be plasticizers or fibers, [ 95 ] micro or nanoparticles. [ 96 ] Formed foam is controlled by the battle between two mechanisms, namely the expansion of the blowing agent and the simultaneous curing of the resin, both of which take place at the same time.…”