溶液沉淀法制备ZnS-氟碳聚合物电纺纤维光催化复合材料

利用含有羧基的氟碳聚合物电纺纤维为载体和模板材料,常温溶液条件下利用均匀沉淀法,在纤维表面负载硫化锌纳米粒子。通过控制反应条件,得到氟碳聚合物电纺纤维表面均匀分布、无团聚的直径在十几纳米左右的硫化锌-氟碳聚合物电纺纤维光催化复合材料。光催化复合材料的高比表面积和水中有机物富集能力使其在紫外光辐照条件下对次甲基蓝降解效率明显高于ZnS粉体。重复降解实验显示复合材料具有较好的稳定性和重复光催化能力。     

Preparation of Highly Fluorinated Poly(ether sulfone)s under Mild Polycondensation Conditions Using Molecular Sieves

Highly fluorinated poly(ether sulfone)s were prepared by a modified polycondensation technique, using a molecular sieve dehydrating apparatus in order to efficiently remove water under mild conditions. Consequently, side reactions were minimized, which resulted in the formation of polymers free of microgels. This reaction was also used to introduce pentafluorostyrene moieties into the polymer to provide crosslinking functionalities.     

Difunctionalization of Alkynes: Synthesis of Novel Fluoropolymer Materials

A Pd‐catalyzed multi‐component carbonylative difluoroalkylation/perfluoroalkylation through the alkyne difunctionalization process has been developed. Besides, new functional fluoropolymer materials have been successfully synthesized. Owing to the presence of the fluorine element, the materials present excellent chemical resistance, high‐temperature‐resistance and outstanding hydrophobicity simultaneously, which may significantly make them great appealing in the industrial production and life science as well.     

Designing superhydrophobic surface based on fluoropolymer–silica nanocomposite via RAFT‐mediated polymerization‐induced self‐assembly

Superhydrophobic surfaces (SHS) find versatile applications as coatings due to their very high water‐repellency, self‐cleaning, and anti‐icing properties. This investigation describes the preparation of a SHS from surfactant‐free hybrid fluoropolymer latex. In this case, reversible addition‐fragmentation chain transfer (RAFT) polymerization was adopted to prepare a copolymer of 4‐vinyl pyridine (4VP) and vinyl triethoxysilane (VTES), where the pyridine units were quaternized to make the copolymer soluble in water. The copolymer was further used as a macro‐RAFT agent to polymerize 2,2,2‐trifluoroethyl methacrylate (TFEMA) in a surfactant‐free emulsion via polymerization‐induced self‐assembly (PISA). The macro‐RAFT agent contained a small amount of VTES as co‐monomer which was utilized to graft silica nanoparticles (SNPs) onto the P(TFEMA) spheres. The film prepared using the nanocomposite latex exhibited a nano‐structured surface as observed by SEM and AFM analyses. Surface modification of the film with fluorinated trichlorosilane produced an SHS with a water contact angle (WCA) of 151.5°. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 266–275     

Characterization and quantification of microstructures of a fluorinated terpolymer by both homonuclear and heteronuclear two‐dimensional NMR spectroscopy

Fluoropolymers are usually insoluble in organic solvents. Insolubility of fluoropolymers limits basic characterization such as microstructural investigations. In the family of fluoropolymers, terpolymer of tetrafluorethylene (TFE), hexafluoropropylene (HFP), and vinylidene fluoride (VDF), named THV is one of the newest members. There are nine grades of THV available. Among the nine grades, THV‐221 G is an ideal model polymer for basic characterization purposes. THV‐221 G is soluble in solvents such as acetone and ethyl acetate. In the current report, both homonuclear and heteronuclear 2D NMR experiments were employed in solution on THV‐221 G. The homonuclear gradient correlation spectroscopy NMR measurement revealed that THV has two adjacent TFE units in addition to TFE‐HFP sequence orders. The fraction of the microstructures is quantified by the analysis of 1D solution ¹⁹F NMR spectrum. Further, the gradient heteronuclear single quantum coherence experiment helped with the clarification of chemical environments of the units TFE, HFP, and VDF. The 1D solution ¹³C NMR spectrum was helpful in clarifying sequence assignments of VDF. It is concluded that THV is a random polymer with a limited fraction of TFE‐TFE and TFE‐HFP sequence orders in addition to head‐to‐tail polymerization of VDF unit. Copyright © 2014 John Wiley & Sons, Ltd.     

Morphology and microstructure of core-shell hybrid latexes containing fluoropolymer and acrylic copolymer

Novel core-shell hybrid latex composed by two immiscible polymers has been prepared. For the first time, we utilized fluoropolymer (FKM-40) as the core while polyacrylates as the shell in this latex, leading two immiscible components mixable under micro-molecular scale. To determine the chemical structure, in particular the miscibility between the core and the shell in this hybrid, transmission electron microscopy (TEM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and FTIR imaging have been performed. All experiments indicate that FKM-40 mixed well with polyacrylates, particularly FTIR image demonstrated unambiguously that FKM-40 dispersed, under micro-molecular scale, in continuous polyacrylates at a concentration of 20%. Further morphology (X-ray diffraction) investigations suggest that the hybrid latex had a less crystalline domain for samples with a lower concentration of FKM-40. Interestingly, we found that the water contact angle and the water absorption of the core-shell hybrid can be readily adjustable by varying the proportion of each species during copolymerization. Finally it is worth mentioning that the core-shell methodology as demonstrated herein is superior to physical blending with regard to its capability of achieving copolymer system under micro-molecular miscibility.     

New hybrid membranes based on phosphonic acid functionalized silica particles for PEMFC

This work concerns the development of hybrid organic/inorganic membranes from styrenic phosphonic polymers. The phosphonic charge, composed phosphonic polymers grafted onto silica nanoparticles, was obtained by “grafting onto” method. It consists of synthesizing first the polymer, and then the terminal functions of the latter react with silanol groups of silica. The phosphonated polymer was isolated in two steps, that is, an ATRP polymerization of 4‐chloromethylstyrene followed by Mickaelïs‐Arbusov reaction. After the grafting onto silica, membranes are prepared through formulation containing the charge and the polymer matrix PVDF‐HFP, which are dispersed in DMF. The acid form is obtained by hydrolysis in chlorydric acid. The membrane possessing a 40 wt % charge ratio (IEC = 1.08 meq g^?1) was selected as reference. A proton conductivity of 65 mS cm^?1 at 80 °C was measured in immersed conditions. When the membrane is no more immersed, the value decreases drastically (0.21 mS cm^?1 at 120 °C and 25% RH). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

EFFECT OF IRRADIATION TEMPERATURE ON GENERAL EQUATION OF SOL FRACTION-DOSE RELATIONSHIP FOR FLUOROPOLYMERS

In this paper, the effect of irradiation temperature on sol fraction-dose relationship of tluoropolymers was studied. It was found that the increasing of irradiation temperature can result in the decreasing of βvalue of fluoropolymer, which increases the crosslinking probability of fluoropolymer. The relationship between crosslinking parameter βand irradiation temperature (T_i)of fluoropolymer is established as follows:β=2.2×10~(-3) T_g+4×10~(-4)(T_g-T_i)+0.206.values of some tluoropolymers calculated from the above expression are in agreement with the experimental values.     

Solid‐state 1H → 19F/19F → 1H CP/MAS NMR study of poly(vinylidene fluoride)

Solid‐state ¹H → ¹⁹F and ¹⁹F → ¹H cross‐polarization magic angle spinning (CP/MAS) NMR spectra have been investigated for a semicrystalline fluoropolymer, namely poly(vinylidene fluoride) (PVDF). The ¹H → ¹⁹F CP/MAS spectra can be fitted by five Lorentzian functions, and the amorphous peaks were selectively observed by the DIVAM CP pulse sequences. Solid‐state spin‐lock experiments showed significant differences in T_1ρ^F and T_1ρ^H between the crystalline and amorphous domains, and the effective time constants, T_HF* and T_1ρ*, which were estimated from the ¹H → ¹⁹F CP curves, also clarify the difference in the strengths of dipolar interactions. Heteronuclear dipolar oscillation behaviour is observed in both standard CP and ¹H → ¹⁹F inversion recovery CP (IRCP) experiments. The inverse ¹⁹F → ¹H CP‐MAS and ¹H → ¹⁹F CP‐drain MAS experiments gave complementary information to the standard ¹H → ¹⁹F CP/MAS spectra in a manner reported in our previous papers for other fluoropolymers. The value of N_F/N_H (where N is a spin density) estimated from the CP‐drain curve is within experimental error equal to unity, which is consistent with the chemical structure. Copyright © 2001 John Wiley & Sons, Ltd.