Synthesis and Characterization of Polycarbonate Copolymers Containing Benzoyl Groups on the Side Chain for Scratch Resistance

The purpose of this study was to enhance the scratch resistance of polycarbonate copolymer by using 3,3′-dibenzoyl-4,4′-dihydroxybiphenyl (DBHP) monomer, containing benzoyl moieties on the ortho positions. DBHP monomer was synthesized from 4,4′-dihydroxybiphenyl and benzoyl chloride, followed by the Friedel-Craft rearrangement reaction with AlCl3. The polymerizations were conducted following the low-temperature procedure, which is carried out in methylene chloride by using triphosgene, triethylamine, bisphenol-A, and DBHP. The chemical structures of the polycarbonate copolymers were confirmed by 1H-NMR. The thermal properties of copolymers were investigated by thermogravimetric analysis and differential scanning calorimetry, and also surface morphologies were assessed by atomic force microscopy. The scratch resistance of homopolymer film (100 μm) changed from 6B to 1B, and the contact angle of a sessile water drop onto the homopolymer film also increased

Branched Sulfonimide-Based Proton Exchange Polymer Membranes from Poly(Phenylenebenzopheneone)s for Fuel Cell Applications

Improved proton conductivity and high durability are now a high concern for proton exchange membranes (PEMs). Therefore, highly proton conductive PEMs have been synthesized from branched sulfonimide-based poly(phenylenebenzophenone) (SI-branched PPBP) with excellent thermal and chemical stability. The branched polyphenylene-based carbon-carbon backbones of the SI-branched PPBP membranes were attained from the 1,4-dichloro-2,5-diphenylenebenzophenone (PBP) monomer using 1,3,5-trichlorobenzene as a branching agent (0.1%) via the Ni-Zn catalyzed C-C coupling reaction. The as-synthesized SI-branched PPBP membranes showed 1.00~1.86 meq./g ion exchange capacity (IEC) with unique dimensional stability. The sulfonimide groups of the SI-branched PPBP membranes had improved proton conductivity (75.9–121.88 mS/cm) compared to Nafion 117 (84.74 mS/cm). Oxidation stability by thermogravimetric analysis (TGA) and Fenton’s test study confirmed the significant properties of the SI-branched PPBP membranes. Additionally, a very distinct microphase separation between the hydrophobic and hydrophilic moieties was observed using atomic force microscopic (AFM) analysis. The properties of the synthesized SI-branched PPBP membranes demonstrate their viability as an alternative PEM material

Branched Sulfonimide-Based Proton Exchange Polymer Membranes from Poly(Phenylenebenzopheneone)s for Fuel Cell Applications

Improved proton conductivity and high durability are now a high concern for proton exchange membranes (PEMs). Therefore, highly proton conductive PEMs have been synthesized from branched sulfonimide-based poly(phenylenebenzophenone) (SI-branched PPBP) with excellent thermal and chemical stability. The branched polyphenylene-based carbon-carbon backbones of the SI-branched PPBP membranes were attained from the 1,4-dichloro-2,5-diphenylenebenzophenone (PBP) monomer using 1,3,5-trichlorobenzene as a branching agent (0.1%) via the Ni-Zn catalyzed C-C coupling reaction. The as-synthesized SI-branched PPBP membranes showed 1.00~1.86 meq./g ion exchange capacity (IEC) with unique dimensional stability. The sulfonimide groups of the SI-branched PPBP membranes had improved proton conductivity (75.9–121.88 mS/cm) compared to Nafion 117 (84.74 mS/cm). Oxidation stability by thermogravimetric analysis (TGA) and Fenton’s test study confirmed the significant properties of the SI-branched PPBP membranes. Additionally, a very distinct microphase separation between the hydrophobic and hydrophilic moieties was observed using atomic force microscopic (AFM) analysis. The properties of the synthesized SI-branched PPBP membranes demonstrate their viability as an alternative PEM material

Sulfonyl Imide Acid-Functionalized Membranes via Ni (0) Catalyzed Carbon-Carbon Coupling Polymerization for Fuel Cells

Polymer membranes, having improved conductivity with enhanced thermal and chemical stability, are desirable for proton exchange membranes fuel cell application. Hence, poly(benzophenone)s membranes (SI-PBP) containing super gas-phase acidic sulfonyl imide groups have been prepared from 2,5-dichlorobenzophenone (DCBP) monomer by C-C coupling polymerization using Ni (0) catalyst. The entirely aromatic C-C coupled polymer backbones of the SI-PBP membranes provide exceptional dimensional stability with rational ion exchange capacity (IEC) from 1.85 to 2.30 mS/cm. The as-synthesized SI-PBP membranes provide enhanced proton conductivity (107.07 mS/cm) compared to Nafion 211® (104.5 mS/cm). The notable thermal and chemical stability of the SI-PBP membranes have been assessed by the thermogravimetric analysis (TGA) and Fenton’s test, respectively. The well distinct surface morphology of the SI-PBP membranes has been confirmed by the atomic force microscopy (AFM). These results of SI-PBP membranes comply with all the requirements for fuel cell applications

Sulfonyl Imide Acid-Functionalized Membranes via Ni (0) Catalyzed Carbon-Carbon Coupling Polymerization for Fuel Cells

Polymer membranes, having improved conductivity with enhanced thermal and chemical stability, are desirable for proton exchange membranes fuel cell application. Hence, poly(benzophenone)s membranes (SI-PBP) containing super gas-phase acidic sulfonyl imide groups have been prepared from 2,5-dichlorobenzophenone (DCBP) monomer by C-C coupling polymerization using Ni (0) catalyst. The entirely aromatic C-C coupled polymer backbones of the SI-PBP membranes provide exceptional dimensional stability with rational ion exchange capacity (IEC) from 1.85 to 2.30 mS/cm. The as-synthesized SI-PBP membranes provide enhanced proton conductivity (107.07 mS/cm) compared to Nafion 211® (104.5 mS/cm). The notable thermal and chemical stability of the SI-PBP membranes have been assessed by the thermogravimetric analysis (TGA) and Fenton’s test, respectively. The well distinct surface morphology of the SI-PBP membranes has been confirmed by the atomic force microscopy (AFM). These results of SI-PBP membranes comply with all the requirements for fuel cell applications

Studies of Grafted and Sulfonated Spiro Poly(isatin-ethersulfone) Membranes by Super Acid-Catalyzed Reaction

Spiro poly(isatin-ethersulfone) polymers were prepared from isatin and bis-2,6-dimethylphenoxyphenylsulfone by super acid catalyzed polyhydroxyalkylation reactions. We designed and synthesized bis-2,6-dimethylphenoxyphenylsulfone, which is structured at the meta position steric hindrance by two methyl groups, because this structure minimized crosslinking reaction during super acid catalyzed polymerization. In addition, sulfonic acid groups were structured in both side chains and main chains to form better polymer chain morphology and improve proton conductivity. The sulfonation reactions were performed in two steps which are: in 3-bromo-1-propanesulfonic acid potassium salt and in con. sulfuric acid. The membrane morphology was studied by tapping mode atomic force microscope (AFM). The phase difference between the hydrophobic polymer main chain and hydrophilic sulfonated units of the polymer was shown to be the reasonable result of the well phase separated structure. The correlations of proton conductivity, ion exchange capacity (IEC) and single cell performance were clearly described with the membrane morphology

Synthesis and Characterization of Sulfonated Poly(Phenylene) Containing a Non-Planar Structure and Dibenzoyl Groups

Polymers for application as sulfonated polyphenylene membranes were prepared by nickel-catalyzed carbon-carbon coupling reaction of bis(4-chlorophenyl)-1,2-diphenylethylene (BCD) and 1,4-dichloro-2,5-dibenzoylbenzene (DCBP). Conjugated cis/trans isomer (BCD) had a non-planar conformation containing four peripheral aromatic rings that facilitate the formation of π–π interactions. 1,4-Dichloro-2,5-dibenzoylbenzene was synthesized from the oxidation reaction of 2,5-dichloro-p-xylene, followed by Friedel-Crafts reaction with benzene. DCBP monomer had good reactivity in polymerization affecting the activity of benzophenone as an electron-withdrawing group. The polyphenylene was sulfonated using concentrated sulfuric acid. These polymers without any ether linkages on the polymer backbone were protected from nucleophilic attack by hydrogen peroxide, hydroxide anion, and radicals generated by polymer electrolyte membrane fuel cell (PEMFC) operation systems. The mole fraction of the sulfonic acid groups was controlled by varying the mole ratio of bis(4-chlorophenyl)-1,2-diphenylethylene in the copolymer. In comparison with Nafion 211® membrane, these SBCDCBP membranes showed ion exchange capacity (IEC) ranging from 1.04 to 2.07 meq./g, water uptake from 36.5% to 69.4%, proton conductivity from 58.7 to 101.9 mS/cm, and high thermal stability

Highly Conductive and Flexible Gel Polymer Electrolyte with Bis(Fluorosulfonyl)imide Lithium Salt via UV Curing for Li-Ion Batteries

A series of new self-standing gel polymer electrolytes (SGPEs) were fabricated by ultraviolet (UV) curing and investigated for application in flexible lithium-ion batteries. Compared with traditional gel polymer electrolytes (combine with solvents or plasticizers), these new SGPEs were prepared simply by curing different weight ratios of lithium bis(fluorosulfonyl)imide (LiFSI) with a methacrylic linear monomer, poly (ethylene glycol) dimethacrylate (PEGDMA). Noticeably, there were no solvents or plasticizers combined with the final SGPEs. Owing to this, the SGPEs showed high flexibility and strong mechanical stability. Some paramount physicochemical and electrochemical characters were observed. The SGPEs demonstrated good thermal stability below 150 °C and an extremely low glass transition temperature (Tg) (around −75 °C). Moreover, plastic crystal behaviors were also identified in this study. Ultimately, the SGPEs demonstrated excellent ionic conductivity at room temperature, which proves that these new SGPEs could be widely applied as a prospective electrolyte in flexible lithium-ion batteries