The fundamental difference between aerogel and foam is that aerogel is a porous insulating material with nanoporous structure at its core, while foam is a porous elastic buffer material with a polymer matrix at its core. The core properties, performance, and applications of the two are completely different and belong to different industrial demand fields.
I. Core Components and Microscopic Structure
(1) Aerogel
The main base material is silicon dioxide, and there are also carbon-based and oxide-based varieties. The porosity is 90% to 99.8%, and the pore size is 1 to 100 nm at the nanoscale;
There is no continuous elastic matrix, and it is a rigid inorganic/organic porous framework.
(2) Foam
The base material is polyurethane, polyethylene, etc., thermoplastic/thermo-setting polymers. The porosity is 50% to 95%, and the pore size is mostly above 1 μm at the micrometer scale;
The polymer matrix forms a continuous elastic network, and it is a flexible/elastic porous structure.
II. Core Performance Differences
Insulation Performance: Under normal temperature and pressure (in accordance with GB/T 10294-2008), the thermal conductivity of aerogel is ≤ 0.012 W/(m·K), which is the current optimal insulating material at normal temperature; the thermal conductivity of foam is 0.03 to 0.06 W/(m·K), which belongs to the ordinary insulation grade;
Mechanical Performance: Aerogel is rigid and brittle, with an compressive strength of ≤ 0.5 MPa, and it is prone to breakage; foam has elastic and ductile properties, with a tensile strength of 0.2 to 10 MPa, which can be compressed and rebound, and has strong resistance to deformation;
Tolerance Characteristics: Ordinary silicon-based aerogel can withstand -200°C to 650°C, and carbon-based can withstand temperatures above 1000°C; foam is mostly resistant to temperatures of -40°C to 120°C, but it is prone to melting and decomposition at high temperatures and brittle at low temperatures;
Functional Characteristics: Aerogel has no buffering and energy absorption capacity; foam can absorb impact through compression deformation, with a buffering coefficient of 5 to 20.
III. Applicable Production/Application Scenarios
Aerogel: Military equipment high-temperature insulation, new energy battery pack insulation, deep cold storage and transportation container insulation, aerospace device insulation;
Foam: Product buffering packaging in electronic production processes, shock absorption sealing parts in household appliances production, sound insulation buffer layer in car interiors, protective padding for logistics turnover.
IV. Production Process Differences
Aerogel: Requires supercritical drying (or conventional pressure drying modification) process, with a long production cycle and high single-batch cost;
Foam: Can be produced through foaming extrusion and molding process, with high production efficiency and low unit cost.