Hong, Wei-Jie;Yuan, Li-Li;Zhang, Hao-Yang;Cui, Chao;Chen, Wei;Yang, Shi-Yong published 《Phenylethynyl-terminated Imide Oligomers Modified by Reactive Diluent for Resin Transfer Molding Application》. The research results were published in《Chinese Journal of Polymer Science》 in 2022.Product Details of 2657-87-6 The article conveys some information:
To meet the processing requirements of resin transfer molding (RTM) technol., reactive diluent containing m-phenylene moiety was synthesized to phys. mixed with phenylethynyl terminated co-oligo imides with well-designed mol. weights of 1500-2500 g/mol derived from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 3,4′-oxydianiline (3,4′-ODA) and m-phenylenediamine (m-PDA). This blend shows low min. melting viscosity (<1 Pa·s) and enlarged processing temperature window (260-361°C). FPI-R-1 stays below 1 Pa·s for 2 h at 270°C. The relationship between the mol. weight of the blend and its melting stability was first explored. Blending oligo-imides with lower mol. weights exhibit better melting stability. Upon curing at 380°C for 2 h, the thermosetting polyimide resin demonstrates superior heat resistance (Tg=420-426°C). The experimental procedure involved many compounds, such as 3-(4-Aminophenoxy)aniline (cas: 2657-87-6) .
3-(4-Aminophenoxy)aniline is one of ethers-buliding-blocks. Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. Product Details of 2657-87-6 The bonding of oxygen in ethers, alcohols, and water is similar. In the language of valence bond theory, the hybridization at oxygen is sp3.
Reference:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem