Acoustically and thermally insulating epoxy foams prepared by non‐traditional expandable microspheres

Abstract

Herein, the acoustically and thermally insulating epoxy foams were prepared using non‐traditional expandable microspheres. The effect of foaming temperature and microsphere content on the morphology, the mechanical strength, the thermal insulation and acoustical properties of the epoxy foams was investigated in detail. It can be found that the closed pores can be partially opened by adjusting the preparation parameters, which is also accompanied by obvious changes in acoustic and thermal insulation properties. By giving high‐content expandable microspheres above 2 wt%, the epoxy foams exhibit highly thermal insulation, and meanwhile achieving an acceptable mechanical property. The results convince us that such light‐weight epoxy foams will outshine as the promising structural, soundproof and heat‐insulated material in many multifunctional systems, such as buildings, vehicles and aircrafts. POLYM. ENG. SCI., 59:799–806, 2019. © 2018 Society of Plastics Engineers

Transport Properties of One-Step Compression Molded Epoxy Nanocomposite Foams

“…Foams within the same density set present fairly similar cell morphology and cell size distribution (Figure 4), with average cell size and wall thickness ranging from 125 ± 5 µm and about 1–2 µm to 56 ± 2 µm and 10–12 µm for low- and high-density foams, respectively (Table 2). The cellular morphology of previous studies presents either a bimodal cell size distribution or the presence of extremely large cells [5,18,20,21,22,23], neither of these two effects were observed in our samples (Figure 4). We ascribe this homogeneity of the cellular structure to the single-step foaming process and to the degassing of the CNP mixture.…”

“…Several studies by Bao and coworkers [18,19,20,21,22,23] on epoxy/Expancel systems reported two-step foaming processes, composed of pre-curing at low temperatures (around 45 °C) and foaming (75 to 100 °C temperature range), followed by traditional epoxy post-curing. The authors stated their intention to adopt a single-step process but they encountered thermal degradation of the matrix.…”

“…The use of CNP has also been explored with epoxy foamed via EMSs. Bao and co-workers have developed a foaming protocol based on a two-step process followed by a traditional post-cure step of epoxy resins [18,19,20,21,22,23]. They have reported lower electrical percolation threshold and higher conductivity than those of the solid counterpart [18], and improvements in both electromagnetic interference shielding and sound absorption properties compared to unfilled samples [20,21,22].…”

One-Step Synthesis of Microdome Patterns for Microstructured Pressure Sensors with Ultra-High Sensing Performance

“…Their expansion is easily controllable and irreversible due to the plastic deformation of the polymer shell (see Figure S1b), which makes it an ideal candidate for simple preparation of tunable surface microstructures. Although TEMs have been widely used for stimuli-response composites and thermally insulating materials, − their application for active sensing materials has not yet been exploited. These unique characteristics of graphene and TEMs combined with silicone rubber encouraged us to develop a mold-free, low-cost, and feasible approach to realize thermally regulated surface microstructures for high-performance microstructured pressure sensors.…”

Preparation of small particle diameter thermally expandable microspheres under atmospheric pressure for potential utilization in wood

“…At a certain high temperature, the alkane inside the TEMs, as core material, could be gasified, thereby generating pressure to expand the softened copolymer shell, finally realizing an increase in the volume of the microspheres as several times larger than their initial state. Based on this unique property, TEMs gradually permeates a number of fields and products, such as adhesives, 1,2 foamed plastics, 3,4 three-dimensional coatings, 5 and even vehicle manufacturing industries. 6 Nevertheless, owing to the increasingly enhanced environmental awareness throughout the world, renewable and degradable biological materials receive much attention.…”