New Advances in Chemical Research in 2021. Catalysts are in the same phase as the reactants. Enzymes are biological catalysts that produce large increases in reaction rates and tend to be specific for certain reactants and products. 273-53-0, Name is Benzoxazole, molecular formula is , belongs to benzoxazole compound. In a document, author is Dai, Xuemin, COA of Formula: https://www.ambeed.com/products/273-53-0.html.
A series of high-performance polyimide copolymer (co-PI) fibers containing phenylenebenzoxazole moiety with one hydroxyl group are synthesized based on the copolymerization of 3,3′,4,4′-biphenyl tetracarboxylic dianhydride (BPDA) with two diamine monomers, namely, p-phenylenediamine (p-PDA) and 5-anino 2 (2 hydroxy-4-aminobenzene)-benzoxazole (p-mHBOA), through a two-step method. The molar ratio of p-PDA/p-mHBOA varies from 10/0 to 0/10. Influences of the p-mHBOA moieties on the thermal stability, crystal structure, crystal orientation, microvoid morphology, and mechanical properties are systemically investigated. Fourier transform infrared results confirm that intra/inter molecular hydrogen bonds come from the OH group and nitrogen atom of the benzoxazole group and/or OH group and the oxygen atom of the carbonyl group of cyclic imide. The glass transition temperatures (T(g)s) of coPI fibers are in the range of 290 degrees C-325 degrees C. The prepared fibers show excellent thermal stabilities, and their T5% is within 528 degrees C-542 degrees C in air. Two-dimensional wide-angle X-ray diffraction spectra indicate that homo-PI and co-PI fibers present a regularly arranged polymer chains along the fiber axial direction. Moreover, the ordered molecular packing along the transversal direction of fibers is destroyed by the copolymerization. Small-angle X-ray scattering results show that co-PI fibers with optimal mechanical properties exhibit the shortest average length (L) and the smallest radius (R) of microvoids. When the pmHBOA/p-PDA molar ratio is 5/5, the fracture strength and initial modulus can reach approximately 30.31 cN/dtex (4.40 GPa) and 894.88 cN/dtex (129.8 GPa), respectively. The relationship between structure and mechanical properties is also discussed. (C) 2018 Published by Elsevier Ltd.
Do you like my blog? If you like, you can also browse other articles about this kind. Thanks for taking the time to read the blog about 273-53-0, COA of Formula: https://www.ambeed.com/products/273-53-0.html.
Reference:
Benzoxazole – Wikipedia,
,Benzoxazole | C7H5NO – PubChem