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Polymeric Nanostructures
Published in Pradipta Ranjan Rauta, Yugal Kishore Mohanta, Debasis Nayak, Nanotechnology in Biology and Medicine, 2019
Debasis Nayak, Pradipta Ranjan Rauta
Dialysis, one of the simplest methods, is relevant for the manufacture of very small polymeric nanoparticles with uniform size distribution. This method employs a semipermeable membranous tube with a required molecular weight cutoff as a physical barrier for the polymers (Chronopoulou, Fratoddi, Palocci, Venditti, & Russo, 2009). In this technique, the applicable polymer is dissolved in an organic solvent and positioned inside the dialysis membranous sheath, which is dialyzed, contrary to a non-solvent solution. Successive and gradual vibrations by a magnetic stirrer at a particular rpm and temperature help increase the interfacial tension of the polymer in the dialysis tube, which progresses towards the development of colloidal suspension of nano-sized polymeric materials (Rane, Kanny, Abitha, & Thomas, 2018). The morphology and particle size distribution of the nanoparticles can be controlled by altering the reaction factors such as solvent/non-solvent pair, molecular weight cutoff of the dialysis membrane, temperature of the overall reaction condition, pH of the solvent/non-solvent pair, rpm of the magnetic stirrer, and concentrations of the polymer and solvent used (Eftekhari & Saito, 2017; El-Say & El-Sawy, 2017). The most commonly used organic solvents are DMSO (dimethylsulfoxide), DMF (dimethylformamide), DMAc (dimethylacetamide), and NMPy (N-methyl-2-pyrrolidinone).
Processes and Technologies for the Recycling and Recovery of Spent Lithium Ion Batteries
Published in Thandavarayan Maiyalagan, Perumal Elumalai, Rechargeable Lithium-ion Batteries: Trends and Progress in Electric Vehicles, 2020
Zhi Sun, Weiguang Lv, Zhonghang Wang, Xiaohong Zheng, Hongbin Cao, Zhang Yi
In an organic solvent dissolution (OSD) method, the selection of an optimum organic solvent (OS) is the key [19]. The dissolution efficiency in this method is greatly affected by the type of binder used as well as the rolling method of electrodes. For PVdF-based electrodes, dimethylformamide (DMF), N,N-dimethylacetamide Dimethylacetamide (DMAC), dimethylsulfoxide (DMSO) are often adopted as OSs in addition to the most commonly used N-methyl pyrrolidone (NMP) [20, 21]. Zhou et al. [22] chose (dimethylformamide) DMF to dissolve polyvinylidene difluoride (PVDF), and they showed that the solubility of PVdF in dimethylformamide (DMF) was 176 g/L at 60 °C. Song et al. [23] effectively separated lithium cobalt oxide ( LiCoO2 ) powder from an aluminium foil in a N-methyl-2-pyrrolidone (NMP) and N,N-dimethylformamide (DMF) solution heated to 70 °C, while retaining the metallic form of the foil. However, neither (N-methyl-2-pyrrolidone) NMP nor dimethylformadide (DMF) is suitable for polytetrafluoroethylene (PTFE) based electrodes. To solve this challenge, trifluoroacetate (TFA) was applied by Zhang et al. [24] to completely separate the cathode material from the aluminium foil with an acetic acid fraction of 15 vol.%, a liquid-to-solid ratio (L/S ratio) of 8 mL/g, at a temperature of 40 °C, and a reaction time of 180 min. Although these methods are efficient dealing with cathodes with a polyvinylidene difluoride or even a polytetrafluoroethylene binder, the OSs used in the separation process are usually expensive and toxic, and thus pose a threat to the environment and human health. In addition, the equipment investment and energy consumption for recycling of used organic solvents are also problems that cannot be ignored.
Valorization of resources from end-of-life lithium-ion batteries: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Francine Duarte Castro, Mentore Vaccari, Laura Cutaia
In the solvent dissolution method, the dissolving agent undermines the adhesion of the binder, favoring the segregation of Al foil from the cathode. The effectiveness of the process is, therefore, a function of chemical affinity between the solvent and solute (the “like dissolves like” principle) (Wang et al., 2019a; Zheng et al., 2018). For PVDF, N-methylpyrrolidone (NMP) has been reported as a suitable solvent, with a solubility of approximately 200 g kg−1 (100 °C) and a high boiling point of approximately 200 °C (Contestabile et al., 2001). N, N-dimethylformamide (DMF) and N, N-dimethylacetamide (DMAC) have also been tested as solvents (Zhou et al., 2010). According to Zhou et al. (2010), the solubility of PVDF in DMF could be as high as 176 g l−1 at 60 °C. For DMAC, the solubility was 214 g l−1 at 70 °C.
Synthesis of novel PVDF-co-PTFE membranes for ethanol–water separation using vacuum membrane distillation
Published in Chemical Engineering Communications, 2023
Pappu Kumar Burnwal, S.P Chaurasia, Md. Oayes Midda
Various solvents such as N, N-dimethyl acetamide (DMAc) (Dong et al. 2014; Yan et al. 2005), N-methyl-2-pyrrolidone (NMP) (Jamalpour et al. 2021; Loh et al. 2018) and dimethylformamide (DMF) (Jamalpour et al. 2021; Young et al. 1999), commonly employed to make the dope solution for the membrane synthesis. In order to create high-quality membranes, solvent–polymer compatibility is needed. Low polymer solubility results in weak solvent–polymer interactions, which makes it less favorable for the preparation of dope solutions (Kim et al. 2016).