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Living cationic ring-opening polymerization of cyclic ethers in the presence of diol was modeled using the method of moments. A widespread kinetic model was developed based on previous experimental studies. Then, the moment and population balance of reactants were obtained. Modeling results were employed to study the influence of initiator and water amounts (as the impurity) as well as feeding policy in polymerization kinetics and final properties of the polymer. In addition, the sensitivity of modeling results to initiation, backbiting, and finally propagation via activated monomer reactions were investigated. Results showed the population of chains is the function of their precursors. In a typical polymerization, chains with diol functionality are the majority. Therefore, most of the polymerized monomers are incorporated into those chains. This makes the chains with diol functionality the determining group in Molecular Weight Distribution (MWD). The kinetics of polymerization and properties of the reactor’s product are highly dependent on the ratio of the rate of propagation via the Activated Monomer (AM) mechanism to the rate of propagation via active chain end (ACE). An increase in this ratio decreases the probability of occurrence of backbiting reaction. Therefore, cyclic dimers are less formed and MWD narrows. On the other hand, decreasing this ratio results in less diol reacted with protonated monomers. Consequently, the rate of regeneration of the initiator and hence the rate of polymerization is decreased. These findings give complete facts about the ring-opening syntheses of polyethers and are valuable for evolving new grades as well as optimization current processes.

In this study, the modeling of polymerization of 1, 3-butadiene in the presence of hydrogen peroxide has been reported for the first time. For this purpose, the Method of double moments was applied. The modeling has been performed to investigate the effect of reaction condition on the properties of synthesized Polybutadiene, and the role of kinetic coefficients on the output of model i.e. sensitivity analysis. A comprehensive kinetic model was developed based on previous experimental studies. Then, the moment and population balance of the reactants were obtained. Modeling results were used to study the role of initiator concentration and the type of solvent in polymerization kinetics and final polymer properties. In addition, the sensitivity of modeling results in a transfer to the initiator, radical coupling, and finally transfer to polymer reactions was investigated. This study opens a way for the engineering of manufacturing the Hydroxyl-Terminated PolyButadiene (HTPB) process to obtain the desired products with optimized reaction conditions. Results show that initiator concentration and type of solvent are important in polymerization kinetics and properties of HTPBs. A higher amount of initiator increases radical concentration and consequently rates of bimolecular termination and at the lower level, rate of propagation, and polymer double bonds reactions.

In this work, we demonstrate a strained Si single nanowire tunnel field effect transistor (TFET) with gate-all-around (GAA) structure yielding Ion-current of 15 μA/μm at the supply voltage of Vdd = 0.5V with linear onset at low drain voltages. The subthreshold swing (SS) at room temperature shows an average of 76 mV/dec over 4 orders of drain current Id from 5 × 10−6 to 5 × 10−2 µA/µm Optimized devices also show excellent current saturation, an important feature for analog performance.