Amine ether was initially used as a novel collector for the direct flotation of quartz to separate the quartz from feldspar under weak alkaline conditions. The flotation results demonstrated that the recovery differences between quartz and feldspar both decreased with the increase in the carbon chain length and number of alkoxy groups of amine ether. A recovery difference of nearly 90 % could be achieved between them at a pulp pH of 8.0 with dodecylamine polyoxyethylene ether (AC1210) serving as the collector. The results of the mechanism analysis demonstrated that AC1210 was effectively adsorbed on the quartz surface via electrostatic interaction and hydrogen bonding. However, the electrostatic repulsion between the K + on the feldspar surface and positively charged NH + groups of AC1210 weakened the adsorption of AC1210 on the surface of feldspar. The difference in the adsorption capacity of AC1210 between the quartz and feldspar promoted the selective direct flotation of quartz from the mixture of quartz and feldspar.
Jiaojiao Shang,Guo Yao,Shaojian Lin,Jianwu Lan,Xia Huang,Wen He
A series of thermoplastic poly(ester-imide-ether) (PEIE) elastomers, with different ratios of soft/hard segment 85/15, 80/20 and 70/30, were prepared from 1, 4-butanediol (BD), poly(tetramethylene glycol) (PTMG) and imide dicarboxylic acid monomer based on 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and glycine (GLY). The chemical structures of the imide dicarboxylic acid and PEIEs were characterized by FT-IR and 1H-NMR, respectively. The intrinsic viscosities, thermal properties and mechanical properties of these PEIEs were investigated. The results show that introduction of imide group endows the PEIEs with excellent thermal stability, the melting point of PEIEs at about 220°C, and the temperature of 5% weight loss appears at the range of 332–358°C. In addition, the mechanical properties of PEIEs are also improved with the increment of imide units, the maximum stress and strain reached to 17.15 MP and 1043.75%, respectively.
High-temperature capacitive energy storage requires dielectric materials to maintain low conduction losses and high discharged energy density under extreme thermal conditions, a critical challenge that drives innovation in advanced dielectric polymers. Herein, amino-functionalized polyhedral oligomeric silsesquioxane (NH 2 -POSS) moieties are covalently grafted onto polyamide-ether-imide (PAEI) backbone terminal groups. The NH 2 -POSS expands intermolecular spacing from 6.94 to 8.11 Å to sterically hinder interchain charge transport. Molecular engineering of the PAEI backbone through DABA and BPADA forms restricts intra-chain charge conduction by -CH 3 -CH-CH 3 - groups. Concurrently, a local state energy level shift (0.14 eV) and carrier deep trap capture (1.21 eV) achieve multidimensional suppression of carrier migration. The modified film exhibits ultralow conductivity (3.29 × 10 −12 S cm −1 at 200 °C) and high energy storage densities of 7.43 J cm −3 (150 °C) and 6.54 J cm −3 (200 °C) with η > 90%. Multiscale simulations, including density functional theory (DFT) calculations of trap depth distributions, molecular dynamics (MD) analyses quantifying chain spacing and fractional free volume (FFV) increase, and finite element modeling of field-dependent conduction pathways, collectively validate the suppression mechanisms. This molecular topology engineering paradigm, synergizing steric confinement and electronic structure tailoring, establishes a generalized framework for extreme-condition dielectric design.
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