Preparation and characterization of toughened polyurea aerogels incorporating linear long‐chain in the structure

Abstract

In order to reduce the brittleness of polyurea (PUA) aerogel, reactive incorporation of linear long-chain poly-1,4-butanediol bis(4-aminobenzoate) (P1000) into PUA backbone was made by reacting mixed diamines with triisocyanates. The mixed diamines were composed of 4,4 0 -diaminodiphenylmethane (MDA) and P1000. PUA aerogels were produced by freeze-drying. The effect of P1000 percentage and solid content on the properties of PUA aerogel was investigated. It was found that the little addition of P1000 has a reinforcing and toughening effect on PUA aerogels, where the samples maintain a high extent of hydrogen bonding and low linear shrinkage, with a more compact and homogeneous microstructure. The resulting aerogels show apparent density between 0.05 and 0.18 g/cm 3 , surface area between 41 and 179 m 2 /g, and initial decomposition temperature of about 300 C. At 10% solid content and 15 mol % P1000 (in mixed diamines), the overall performance is optimal, with low apparent density (0.113 g/cm 3 ), low thermal conductivity (0.021 W/m K), and high modulus (compressive modulus 7.4 MPa; flexural modulus 18.8 MPa).

Thermal degradation behavior and kinetics of porous polymer based on high functionality components

“…All products were post‐cured at ambient temperature for 1 week before characterization. The sol–gel method 19 was used to prepare H‐PUA based on polyisocyanate of high functionality. Stilled water, acetone, and triethylamine were first added and mixed in the flask.…”

“…New types of rigid polyurethane foam (H-RPUF) and polyurea aerogel (H-PUA) were prepared by using reaction components with high functionality. Compared with common porous materials, H-RPUF and H-PUA have better heat resistance and mechanical properties, 18,19 which can meet the use conditions of the formation. In the process of heavy oil thermal recovery, porous materials need to be continuously used at high temperature, so the thermal degradation behavior and thermal stability of these materials have a significant impact on heavy oil recovery efficiency.…”

Lightweight polybenzoxazole aerogels with high compressive strength, ultralow dielectric constants, and excellent thermal stability

“…9). 13,23,28,[39][40][41][42][43][44] The 5% thermal decomposition temperatures (T d5 ) of the BAP, 6FAP, and DHB aerogels were 520 °C, Paper Polymer Chemistry 540 °C, and 600 °C, respectively, whereas those of the BAP-HA, 6FAP-HA, and DHB-HA aerogels were 239 °C, 216 °C, and 202 °C, respectively. Clearly, the polybenzoxazole aerogels exhibited higher thermostability than the PHA aerogels owing to the formation of benzoxazole rings during heat treatment.…”