Polymerization Mechanism of Methyl Methacrylate Initiated by Ethyl Acetate/t-BuP4

One‐step synthesis of macromonomers catalyzed by phosphazene base

“…Signals a and b at chemical shifts of 136.22 and 114.33 ppm attributed to the carbon atoms of the double bond C H 2 = C H–Ph–C(O)–N<are clearly visible, proving the existence of the double bond from N ‐BVBA. The signal h corresponding to the macromonomer terminal structure (– C –H, h) was also found at the chemical shift of 35.08 ppm . All these results confirmed that the MM was successfully synthesized in one‐step initiated by N ‐BVBA/ t ‐BuP 4 .…”

“…M n.SEC of MM‐1 agrees with the theoretical molecular weight ( M n.theo = 2200 g mol −1 ), and the M n.SEC / M n.theo value (1.09) is approximate to 1.0, indicating that the polymerization can proceed controllably under the selected conditions. Then, the influence of the [ N ‐BVBA] 0 /[ t ‐BuP 4 ] 0 ratio was studied, because the ratio of [initiator] 0 /[ t ‐BuP 4 ] 0 was found to significantly affect the molecular weight and the molecular weight distribution of the resulting polymer in our previous study . When the ratio of MMA to N ‐BVBA was set to 20/1, it was found that whether increasing the loading of the catalyst t ‐BuP 4 relative to N ‐BVBA to 1.2/1 or decreasing it to 0.8/1 (MM‐5 and MM‐6 in Table ), the M n.SEC of the prepared MMs were out of control.…”

“…That is, the styrenic double bond in N ‐BVBA at the α chain‐end of PMMA macromonomer was intact, and styrenic macromonomer were successfully prepared in one‐pot. Signal h at chemical shift of 2.40 ppm is attributed to the ω chain‐end formed by the quenching reaction of the PMMA chain terminal anion with acetic acid as shown in Scheme b …”

“…Organocatalytic polymerization provides new opportunities for metal‐free polymer materials . Phosphazene bases t ‐BuP 4 , one of the most powerful small molecule organocatalyst, can catalyze anionic or quasi‐anionic polymerization of various types of monomers including lactones, epoxy compounds, lactams, (meth)acrylates, fatty aldehydes and so on, affording polymers with predictable molecular weights and high end‐group fidelity under mild conditions . Interestingly, it was found that t ‐BuP 4 cannot catalyze the polymerization of styrenic and vinyl ether monomers .…”

The advantage of artificial intelligence application in financial risk assessment and management

“…Wang Xuying combined ANN with BP (Back Propagation) algorithm to build up a risk assessment model for financial information systems, examining the risk level of the information system through the data provided by 60 financial institutions by the end of 2021 [5]. Xia Jiajia takes Anhui Province as an example, using a recurrent neural network (RNN) model with memory ability to evaluate and study financial risk [6]. Their models and results strongly suggest that ANN models can predict and stimulate real-world situations and give an accurate analysis of potential risks.…”