Preliminary examination of electrochemical and spectroscopic features of trithiocarbonate collectors for sulfide mineral flotation

The redox potentials of xanthate/dixanthogen (dithiocarbonate/di dithiocarbonate, DTC/(DTC) 2) and trithiocarbonate/di trithiocarbonate (TTC/(TTC) 2) couples have been measured for the potassium salts. The spectroscopic characteristics of these sulfide mineral collectors were determined by FTIR and UV analysis. Electrochemically controlled contact angle measurements at a pyrite surface provided the basis to analyze the effect of the functional group ( O CS 2 versus S CS 2) on the hydrophobic surface state. Results from this preliminary examination are discussed with respect to the nature of collector adsorption and the pyrite flotation response.

PHOTO-INDUCED GRAFT POLYMERIZATION OF ACRYLAMIDE ON POLYPROPYLENE MEMBRANE SURFACE IN THE PRESENCE OF DIBENZYL TRITHIOCARBONATE

Ultraviolet （UV）-induced graft polymerization of acrylamide （AAm） on polypropylene substrates was successfully conducted using dibenzyl trithiocarbonate （DBTTC） as photoinitiator. It was confirmed by chemical analysis and surface morphology observation with attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. A possible mechanism for this graft process was presented, which suggested that, under UV irradiation, the C： S bond in DBTTC could split and abstract a hydrogen from the polypropylene surface and a surface free radical was then formed, and initiated the graft polymerization of AAm.

STYRENE POLYMERIZATION MEDIATED BY CYCLIC TRITHIOCARBONATE AS RAFT AGENT

The novel cyclic trithiocarbonate was synthesized by dialkylation of trithiocarbonate anion with 2,2＇- bis（bromomethyl）biphenyl in a two-phase system using an onium salt as a phase-transfer agent. Styrene polymerization was carried out in the presence of cyclic trithiocarbonate （CTTC）. CTTC undergoes ring opening-polymerization and the incorporated trithiocarbonate moiety derived from CTTC performs as the reversible addition-fragmentation chain transfer （RAFT） agent. Through this mechanism, multiblock polys-tyrenes containing various narrow polydispersity blocks can be prepared.

DFT-supported Mechanistic Understanding of the Ring-opening Polymerization of Cyclic Trithiocarbonates Mediated by Organic Base

Sulfur-rich polymers are endowed with several enhanced features,such as high refractive index and excellent thermal and mechanical properties,owing to the incorporation of sulfur atoms into the polymer main chain.As an important category of sulfur-rich polymers,polytrithiocarbonates can be efficiently synthesized through ring-opening polymerization(ROP)of cyclic trithiocarbonates(CTCs)mediated by 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)and benzyl mercaptan(BnSH).However,the mechanistic investigations of this reaction are limited.In this study,we attempted to understand this reaction by simulating chain initiation,propagation,and termination in the ROP of CTCs using density functional theory(DFT)calculations.As demonstrated,the acceleration of the ROP ofδ-CTC by BnSH can be attributed to the smaller size of BnS-compared to TBD when nucleophilic attacking,and[TBDH]+enhancing the interaction with the monomer and stabilizing the generated active species in the initiating process.In addition,the ability of BnSH to tune the topological structures of the final polymers is ascribed to the suppressed transesterification between the thiolate species and the first trithiocarbonate unit initiated by BnS-.Furthermore,the limitations that hinder the ROP of five-and six-membered CTCs under general conditions are the unfavored thermodynamic factors,wherein the ROP of six-membered CTC is possible below-75℃.

Photodegradation-Induced Turn-On Luminescence of Tetraphenylethylene-Based Trithiocarbonate Polymers

Main observation and conclusion Fluorescent intelligent materials have attracted wide attention because of their great potential applications.One major hurdle for the development and application of fluorescent intelligent materials is the aggregation-caused quenching effect in the solid state.Herein,tetraphenylethylene-based trithiocarbonate polymers with satisfactory molecular weights(Mw up to 24900)were synthesized through a one-pot polymerization route under mild conditions.The polymers were non-emissive due to the quenching effect of the trithiocarbonate group.However,upon UV irradiation,the polymers degraded and strong emission from the tetraphenylethylene unit was observed.Such a unique property endows them with great potential applications,such as photopatterning,anti-counterfeit labels,and UV detection.