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From 2,5-furan dicarboxylic acid, a robust biomass platform molecule, furan-based porous polyamide ( FPPA-1 and -2 ) was synthesized and applied for the removal of Hg2+ from water. FPPA-1 and -2 were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The effects of pH, dosage, contact time, temperature and concentration on the adsorption of Hg2+ were systematically investigated. The pseudo-second-order kinetics and the Langmuir isotherm model are in the best agreement with the experimental data, and the maximum adsorption capacity is 462 mg g−1. Thermodynamically, the adsorption of Hg2+ is a spontaneous adsorption process. There was no significant loss of performance during five regeneration cycles. In combination with the experimental data and density functional theory (DFT) calculation, the chelation mechanism of Hg2+ was demonstrated. Our study offers new perspectives for the removal of Hg2+ from wastewater. [Display omitted] • Furan-based porous polyamides were successfully prepared and removed Hg2+ from water. • The highest adsorption capacity of furan-based porous polyamide for Hg2+ was 462 mg g-1. • Hg2+ adsorption mechanism was proposed by spectral technique and DFT calculations. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we designed and synthesized five novel reversible addition–fragmentation chain transfer (RAFT) agents bearing naphthyl moieties in the Z or R groups, including 3,4,5-trimethoxy-benzyl dithio-2-naphthalenoate (TOBDN), 4-nitrobenzyl dithio-2-naphthalenoate (NBDN), 1-menaphthyl 4-cyanodithiobenzoate (NCDB), 1-menaphthyl dithiobenzoate (NDB) and 1-menaphthyl dithio-2-naphthalenoate (NDN). The RAFT polymerizations of styrene mediated by these RAFT agents with AIBN as the initiator at 80°C were conducted and evaluated. Except for NCDB, the RAFT agents showed good control over the polymerization at different RAFT agent concentrations: the M n,GPC increased linearly with the monomer conversion, and the PDIs of the polymers were relatively low (PDI=1.20–1.50). The structure of RAFT agents bearing three different R groups with naphthyl as the Z group showed less effects on the polymerization rate, while those bearing different Z groups with 1-menaphthyl as the Resented significant effects on the polymerization rates. The polymerization rate with phenyl as the Z group was higher than that with 2-naphthyl as the Z group, and it decreased significantly when using 4-cycno phenyl as the Z group. Retardation effects were observed with all the RAFT agents. 1H NMR spectra and chain extension results confirmed that most of the polymer chains were “living”. Ultraviolet (UV) absorption of naphthyl moieties at the Rowed blue shifts compared with those of naphthyl at the Z group. The UV absorption intensity of PS was uniformly lower than that of the corresponding RAFT agent, while the fluorescence intensity of PS was higher than that of the corresponding RAFT agent. [Copyright &y& Elsevier]

Abstract: Reversible addition–fragmentation chain transfer polymerization (RAFT) of styrene (St) was carried out in the presence of oxygen using 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) or benzyl (2-phenyl)-1-imidazolecarbodithioate (BPIC) as the RAFT agent. The characteristics of the “living”/controlled radical polymerization were observed at high concentration of RAFT agent and low polymerization temperature. A slight increase in the rate of polymerization was found when oxygen was added at high concentration to the polymerization system; however, the presence of oxygen incurred greater polydispersities of the polymer at the same monomer conversion compared to that obtained in the absence of oxygen. The possible mechanism of the RAFT polymerization of St in the presence of oxygen was discussed. [Copyright &y& Elsevier]

Abstract: Thermal polymerization of methyl (meth)acrylate (MMA) was carried out using 2-cyanoprop-2-yl-1-dithionaphthalate (CPDN) and cumyl dithionaphthalenoate (CDN) as chain transfer agents. The kinetic study showed the existence of induction period and rate retardation, especially in the CDN mediated systems. The molecular weights of the polymers increased linearly with the monomer conversion, and the molecular weight distributions (M w/M ns) of the polymers were relatively narrow up to high conversions. The maximum number-average molecular weights (M ns) reached to 351 900g/mol (M w/M n =1.47) and 442 400g/mol (M w/M n =1.29) in the systems mediated by CPDN and CDN, respectively. Chain-extension reactions were also successfully carried out to obtain higher molecular weight PMMA and PMMA-block-polystyrene (PMMA-b-PSt) copolymer with controlled structure and narrow M w/M n. Thermal polymerization of methyl acrylate (MA) in the presence of CPDN, or benzyl (2-phenyl)-1-imidazolecarbodithioate (BPIC) also demonstrated “living”/controlled features with the experimented maximum molecular weight 312 500g/mol (M w/M n =1.57). The possible initiation mechanism of the thermal polymerization was discussed. [Copyright &y& Elsevier]

Recently the research on the materials for removal of heave metals is surging rapidly. Here we have studied four triazine-based sulfur-containing polymers with different linkers, namely PDT1, PDT2, EDT1, and EDT2. They have been successfully synthesized by the nucleophilic substitution reaction of cyanuric chloride with propane-1,3-dithiol (PDT1 and PDT2) and ethane-1,2-dithiol (EDT1 and EDT2) in different ratios. The physical and chemical properties of these polymers were characterized by scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, porous structure analysis and X-ray photoelectron spectroscopy. The optimized adsorption condition was established by examining dosing, co-existing substances, contact time, concentration, temperature and pH values. The adsorbing properties, which was mainly described by the pseudo-second-order kinetic and Langmuir isothermal model, indicated that the sorption of Hg2+ was the chemical adsorption. The maximum Hg2+ sorption capacities of PDT1 , PDT2 , EDT1 and EDT2 were 1440.97 mg g−1, 715.99 mg g−1, 237.87 mg g−1 and 181.48 mg g−1, respectively. Thermodynamically, the adsorption of Hg2+ by the adsorbent is a spontaneous process. Cyclic experiments demonstrated that all the adsorbents could be reused in five successive adsorption cycles without significant losses in performance. Our density functional theory calculations in combination with relevant experimental results revealed the coordination geometry of Hg and hence mercury-adsorbent chelation mechanism. These results suggested that triazine-based sulfur-containing polymers could be utilized as effective adsorbents for the removal of Hg2+ from polluted water. [Display omitted] • Four triazine-based sulfur-containing polymers with different linker were readily prepared. • The polymers shown a higher adsorption capacity for Hg2+ (up to 1441 mg g−1) and could be easily reused. • Based on experimental facts and DFT calculations, the adsorption mechanism of the polymers was proposed. [ABSTRACT FROM AUTHOR]

Abstract: Here, we described a strategy for preparing well-defined block copolymers, poly(styrene)-b-poly(vinyl acetate) (PS-b-PVAc), containing middle azobenzene moiety via the combination of the reversible addition-fragmentation chain transfer (RAFT) polymerization and “click” chemistry. Firstly, a novel RAFT agent containing α-alkyne and azobenzene chromophore in R group, 2-(3-ethynylphenylazophenoxycarbonyl)prop-2-yl-9H-carbazole-9-carbodithioate (EACDT), was synthesized and used to mediate the RAFT polymerization of styrene (St). Well-defined α-alkyne end-functionalized poly(styrene) (PS) was obtained. Secondly, the RAFT polymerization of vinyl acetate (VAc) was conducted using functionalized RAFT reagent with ω-azide structure in Z group, O-(2-azidoethyl) S-benzyl dithiocarbonate (AEBDC). Well-defined ω-azide end-functionalized poly(vinyl acetate) (PVAc) was obtained. Afterwards, the resulting α-alkyne terminated PS was coupled by “click” chemistry with the azide terminated PVAc. The block copolymer, PS-b-PVAc, was obtained with tailored structures. The products from each step were characterized and confirmed by GPC, 1H NMR, IR and differential scanning calorimetry (DSC) examination. Kinetics of the trans-cis-trans isomerization from azobenzene chromophore in PS-b-PVAc and PS were investigated in CHCl3 solutions. [Copyright &y& Elsevier]

Abstract: The macro-TEMPO agent (poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), PGTEMPO) was synthesized by anion ring-opening polymerization (ROP) of 4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (GTEMPO) using potassium t-butoxide as the initiator. The comb-shaped copolymer, PGTEMPO-g-PVBK, was prepared via nitroxide-mediated free radical polymerization (NMP) using PGTEMPO as macro-TEMPO agent and 9-(4-vinylbenzyl)-9H-carbazole (VBK) as the monomer. The polymerizations showed characteristics of “living”/controlled behavior. The optical properties, thermal analysis and electrochemical properties of the comb-shaped copolymers were investigated. The fluorescence and ultraviolet intensity and cyclic voltammetries of the comb-shaped copolymers with different molecular weight showed a regular order. [Copyright &y& Elsevier]

Abstract: The optimal conditions for the hydrogen bonding interaction between 4-vinylpyridine (4VP) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) were screened via UV-vis spectroscopy. The results demonstrated that equimolar 4VP and HFIP, and temperature at 25 °C favored a better hydrogen bonding interaction. Guided by these primary results, the room-temperature Cu(0)-mediated controlled radical polymerization was selected for the controlled polymerization of 4VP in the presence of equiv. HFIP. The polymerizations produced polymers with more predictable number-average molecular weights (M n ,SEC) and narrower molecular weight distributions (M w /M n <1.25) in comparison with those without hydrogen bonding interaction. Moreover, the hydrogen bonding had profound impacts on the stereoregulation during polymerization, which enabled P4VP with a highly syndiotactic (60.2%) and gave rise to a higher glass transition temperature (T g ) of P4VP. [Copyright &y& Elsevier]

Abstract: A novel α-azide and ω-alkyne A–B type azobenzene monomer, 3′-ethynylphenyl[4-(4-azidobutoxy)phenyl]azobenzene (EAPA), was synthesized and used to generate a novel polymer via step-growth polymerization using 1,3-dipolar cycloaddition reaction under the catalysis of CuSO4·5H2O/sodium ascorbate/H2O (“Click” chemistry). The structure of the resultant main-chain azobenzene polymer, PEAPA, was characterized by GPC, 13C NMR, UV–vis and FT-IR spectra. Thermal stability and crystallinity of PEAPA powder were studied by TGA and WAXD. The photo-induced trans–cis isomerization of PEAPA and EAPA in N,N′-dimethyl formamide (DMF) solution was investigated. Furthermore, the thermal cis–trans isomerizations of PEAPA and EAPA were also observed at 60°C in dark. Thermal stability and trans–cis–trans isomerization behavior of PEAPA was compared with its non-triazole analog, PDHA. [Copyright &y& Elsevier]

Abstract: The light sensitive vinyl monomer with coumarin unit, 7-(4-(acryloyloxy)butoxy)coumarin (7AC), was synthesized. The reversible addition–fragmentation chain transfer (RAFT) polymerization of 7AC, initiated by 2,2′-azobisisobutyronitrile (AIBN), was carried out using 2-cyanoprop-2-yl dithiobenzoate (CPDB) as a RAFT agent in N,N-dimethylformamide (DMF) solution. The kinetics exhibited first-order relationship with respect to the monomer concentration. The molecular weight of the polymer increased linearly with the monomer conversion. The chain extension of poly(7-(4-(acryloyloxy)butoxy)coumarin) (P7AC) using styrene (St) as the second monomer demonstrated that the obtained polymers were almost “living”. The fluorescence intensity of P7AC increased with the molecular weight of P7AC and was stronger than that of the monomer. The obtained polymer had strong ultraviolet (UV) absorption at 322nm. The molecular weights of the polymer had no effect on its ultraviolet absorption intensity. The coumarin structure existing in P7AC underwent [2+2] cycloaddition reaction (photodimerization) under UV irradiation in tetrahydrofuran (THF) solution, which can be further used to prepare small particles from the single polymer. [Copyright &y& Elsevier]

Abstract: A novel benzodithioate compound with a pyrene structure in the R group, pyrenylmethyl benzodithioate (PMB) was synthesized. Using PMB as the chain transfer agent (CTA), the RAFT polymerizations of styrene with AIBN as an initiator were carried out in different reaction conditions. The results indicated that PMB was an effective CTA for the RAFT polymerizations of styrene with the “living”/controlled characteristics. The structures of the obtained polymers were characterized by 1H NMR. The results showed that majority of the polymer chains contained the pyrene moiety in the chain end. The enhanced fluorescence property in CHCl3 solution was observed. The chain-extension experiments of the obtained polystyrene (PS) with the monomers of styrene and methyl acrylate were successfully carried out. [Copyright &y& Elsevier]