AB2 Monomer Research Articles

Hyperbranched conjugated polymers based on 4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole for ternary organic solar cells

A new class of end-modifiable hyperbranched conjugated polymer (HBCP–Br) was synthesized from an AB2 monomer, and the end-modification of HBCP-Br was carried out by substituting the end-Br with a donor group to give the end-modified HBCPs (HBCP-OR). Both polymers had relatively good thermal stability (Td > 350 °C) and deep HOMO energy levels (−5.40 eV for HBCP-OR, −5.45 eV for HBCP-Br). Besides, the other two similar small molecular acceptors (IDTOTZ and IDTCPT) were synthesized to construct ternary organic solar cells (OSCs) with HBCP-OR or HBCP-Br. Owing to the favorable spectral and energy levels matching and relatively regular morphology, the ternary OSCs based on HBCP-OR/IDTOTZ/IDTCPT obtained an optimized PCE of 4.86% (with an open-circuit voltage (VOC) of 0.893 V, a short-circuit current density (JSC) of 11.71 mA, and a fill factor (FF) of 45.18%), which performed better than the devices based on HBCP-Br/IDTOTZ/IDTCPT with a PCE of 2.33%. In addition, the HBCP-Br also exhibited photovoltaic activity when used as acceptors in the ternary OSCs based on small molecular donors, which demonstrated that HBCPs could play different roles in the OSCs.

Progressive Applications of Hyperbranched Polymer Based on Diarylamine: Antimicrobial, Anti-Biofilm and Anti-Aerobic Corrosion.

New generations of hyperbranched aramids were synthesized from diarylamine and methyl acrylate using an AB2 monomer approach in a straightforward one-pot preparation. The chemical structure of hyperbranched Phenylenediamine/Methyl Acrylate HB(PDMA was confirmed by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (1HNMR) spectroscopy. In addition, the particle’s size and distribution were recorded using Dynamic Light Scattering (DLS). Moreover, the synthesized HB(PDMA)s displayed broad-spectrum antimicrobial activities against Gram-positive and Gram-negative bacteria as well as yeast strains and anti-biofilm activity where the highest activity was attributed to HB(PDMA)G4 at the lowest Minimum Inhibitory, Minimum Bactericidal, and Fungicidal Concentrations (MIC, MBC, and MFC, respectively). Furthermore, the HB(PDMA)s expressed anti-bacterial activity against isolated Pseudomonas sp. (R301) at a salinity of 35,000 ppm (NaCl). In addition, they revealed different corrosion inhibition efficiencies at the cultivated medium salinity at the estimated minimum bactericidal concentrations. The highest metal corrosion inhibition efficiencies were 59.5 and 94.3% for HB(PDMA)G4 at the Minimum Bactericidal Concentrations (MBCs) and two times Minimum Bactericidal Concentrations (2XMBCs), respectively, in comparison to both negative and positive controls.

Design and synthesis of cinchona-based chiral hyperbranched polymers and their application in asymmetric reactions

Cinchona-based chiral hyperbranched polymers (HBPs) were designed and successfully synthesized via the Mizoroki-Heck (MH) coupling reaction. AB2 and A2B-type chiral monomers were prepared from cinchona squaramide derivatives, where A (vinyl) reacted only with B (iodophenyl) under MH reaction conditions. The chiral HBPs obtained by the MH polymerization contained cinchona squaramide moieties and demonstrated excellent diastereoselectivity and enantioselectivity in asymmetric Michael addition reactions of methyl 2-oxocyclopentanecarboxylate and trans-β-nitrostyrene. These newly designed HBPs were structurally robust and could be reused for further reaction without losing their catalytic activity.

Kinetically controlled cyclization in step-growth polymerization of AB2 macromonomer: Role of molar mass of macromonomer

Cyclization has been widely reported to compete with interchain growth and lead to limited degree of polymerization in step-growth polymerization of AB2 monomers. However, little attention has been paid to kinetical comparison between interchain growth and cyclization in preparation of long-subchain hyperbranched polymers (LHPs) from AB2 macromonomers in semi-dilute solution. This work aims to elucidate how cyclization influences the polymerization of AB2 macromonomers via kinetical competition with interchain growth and how molar mass of macromonomer affects this competition. The corresponding kinetics in semi-dilute solution is theoretically derived in consideration of cyclization. For a given mass concentration, interchain growth rate (rg), cyclization rate (rc) and their ratio (rg/rc) highly depend on the molar mass of macromonomer (M), following the scale rule of rg∝M−2, rc∝M−2.5 and rg/rc∝M0.5, respectively. It indicates that macromonomers with lower molar mass tend to generate products with lower degree of polymerization in terms of macromonomer (DPmacromonomer) and higher self-cyclized macromonomer ratio (CMMR) at a faster rate, while macromonomers with higher molar mass act oppositely. These proposed theories are further verified via the experimental investigation about the step-growth of AB2 polystyrene (PSt) macromonomers with different molar masses. The structural analyses of the resultant products from PSt macromonomers with a low molar mass of 2.5 k indicate a very low DPmacromonomer with a nearly complete conversion of focal A groups, which implies predominant position of cyclized compositions in resultant products, not only cyclized macromonomers (CMMs) but also cyclized long-subchain hyperbranched polymers (CLHPs). More importantly, experimental results show that conversion rate and CMMR increase but DPmacromonomer decreases sharply as molar mass of macromonomer decreases, which quite agrees with the theoretical inference.

Facile and solvent-free synthesis of a novel bio-based hyperbranched polyester with excellent low-temperature flexibility and thermal stability

In this work, a novel biobased hyperbranched polyester (HBPE) with excellent low-temperature flexibility (low Tg) and thermal stability, was prepared from the self-polycondensation of AB2 monomer based on methyl ricinoleate (MR), a commercially available derivative from castor oil. The AB2 monomer was facilely synthesized by UV-initiated thiol-ene addition between MR and 2-mercaptoethanol in the absence of solvents. The reaction parameters were systematically optimized, and the highest yield up to 98 % was achieved with almost complete conversion of double bond within 2 h. A series of HBPEs were then obtained via bulk polymerization of the AB2 monomer under different conditions. Among the four transesterification catalysts investigated, Ti(OBu)4 was demonstrated to be the most efficient one due to the higher polymerization efficiency and molecular weight (Mn = 13,000∼17,000 g/mol) of as-obtained HBPEs. And the degree of branching (DB) was estimated to be in the range of 0.30∼0.42. Notably, the HBPEs with dangling chains exhibited a low glass transition temperature (Tg) of ―42.8∼―59.2 °C, indicative of excellent low-temperature flexibility. TGA results indicated that the onset thermal degradation temperature under nitrogen exceeded 310 °C for all the HBPEs. In comparison to the polyrincinoleate as a linear polyester analogue, the HBPE behaved like Newtonian fluid behaviors with lower complex viscosities.

The Introduction of the Radical Cascade Reaction into Polymer Chemistry: A One-Step Strategy for Synchronized Polymerization and Modification.

SummaryPolymerization and modification play central roles in polymer chemistry and are generally implemented in two steps, which suffer from the time-consuming two-step strategy and present considerable challenge for complete modification. By introducing the radical cascade reaction (RCR) into polymer chemistry, a one-step strategy is demonstrated to achieve synchronized polymerization and complete modification in situ. Attributed to the cascade feature of iron-catalyzed three-component alkene carboazidation RCR exhibiting carbon-carbon bond formation and carbon-azide bond formation with extremely high efficiency and selectivity in one step, radical cascade polymerization therefore enables the in situ synchronized polymerization through continuous carbon-carbon bond formation and complete modification through carbon-azide bond formation simultaneously. This results in a series of α, β, and γ poly(amino acid) precursors. This result not only expands the methodology library of polymerization, but also the possibility for polymer science to achieve functional polymers with tailored chemical functionality from in situ polymerization.

Novel branched sulfonated poly(arylene ether)s based on carbazole derivative for proton exchange membrane

Proton exchange membrane (PEM) is a vital part of polymer electrolyte fuel cells (PEFCs). So it is of great importance to design the novel polymers for PEMs to improve the performance of PEFCs. Here two highly branched sulfonated copolymers (SBP-Cz-x) were synthesized based on a novel AB2 monomer. For all we know, it is the first time that the 9H site of carbazole was used to prepare branched polymers. These copolymers given tough and transparent membranes by solvent casting method. SBP-Cz-x membranes exhibited excellent thermal stability and remarkable dimensional stability. Moreover, proton conductivity of SBP-Cz-x was very excellent. SBP-Cz-15 (IEC = 1.33 meq.g−1) owned high proton conductivity of 42.1 mS cm−1 at 80 °C. SBP-Cz-15 showed a pretty low swelling ratio of 12.7% with high water uptake (32.0%). SBP-Cz-x also owned remarkable oxidation stability. This study demonstrated that the strategy of fixing locally dense sulfonic acid groups on the branched points, which were surrounded by hydrophobic segment, could improve oxidative stability and dimensional stability efficiently.

Model of hyperbranched polymers prepared via polymerization of AB2 and core C3 monomers in a continuous-stirred tank reactor

The formation of hyperbranched polymers (HBPs) generated by the stepwise polymerization of AB2 monomers with the addition of trifunctional core monomers in a continuous-stirred tank reactor, CSTR, was investigated by a kinetic model. The dependency of the degree of polymerization (DP), the degree of branching (DB), and conversion on the Damköhler number (Da) were calculated by a generating function method. When using the polymerization system without the core monomers, the process could be halted due to the production of larger molecules at the conversion of group A, α(A), of approximately 0.44. The addition of core monomers with high reactivity in the CSTR could retard the growth of polymers. Consequently, the reduced weight-average DP and DB could reach 1000 and 0.51, respectively, at a high α(A) of 0.91. Moreover, the amount of unreacted monomers remaining in the flow exiting the CSTR was much less than that without the addition of the core monomers.

Synthesis and characterization of novel functional hyperbranched polyamides from AB2 units: effect of extra functional groups

ABSTRACT Hyperbranched polymers (HPs), which in terms of structure may be compared to the branching structure of trees, are referred to as tree-like materials, but role of leave in these tree-like polymers is neglected and much attention has only been paid to their branches. In fact, functional groups in these polymers play a vital role the same as the role of leaves in trees. Therefore, in this paper, an attempt has been made to design and synthesize three AB2 monomers containing extra hydroxyl and nitro groups. The benefits of their presence in the structure of produced hyperbranched polyamides (HPs) are investigated. The polymer structure was characterized by FT-IR and 1 H NMR. The solubility of synthesized HPs was studied in different protic and aprotic solvents. The thermal stability of the prepared HPs was investigated by thermogravimetric and differential scanning calorimetric analyses. The photoluminescent properties of the HPs were also investigated.

Recyclable Palladium-Loaded Hyperbranched Polytriazoles as Efficient Polymer Catalysts for Heck Reaction

Two polytriazole-based hyperbranched polymers (HBPs) with different molecular weights were prepared by chain-growth Cu-catalyzed azide–alkyne cycloaddition (CuAAC) polymerization of an AB2 monomer....

Synthetically Induced 1→4‐C Branching Motif ‐ An Access Towards Dense Urethane Connecting Dendritic Scaffolds and Application in Nuclear Track Detection

AbstractA series of dumbbell‐shaped urethane connecting polyoleifinic dendrimers, are synthesized from commercial AB2 monomer through the concept of post‐generative synthetic induction of novel 1→4‐C branching motif in divergent and convergent growth methodology using carbamoyl chloride reactivity. A synthetic protocol is conducted through the iterative process of O‐carbamoyl‐allylation of hydroxyls followed by Upjohn dihydroxylation of the allylic double bonds, leading to protection/deprotection free divergent pathway. In parallel, convergent growth route gains dendrimers in relatively good yields. Also, the process of O‐carbonyloxy‐allylation of [G‐1] polyol affords urethane‐carbonate framework providing access to 1→2‐C branching further. Incorporation of current branching motif results in dendritic scaffold with dense periphery at lower generations itself. Free radical cast polymerization of [G‐0.5] dendrimer with allyl diglycol carbonate (ADC) produces thermoset polymer films, showing good sensitivity and ability to permanently record nuclear tracks.

Synthesize Hyperbranched Polymers Carrying Two Reactive Handles via CuAAC Reaction and Thiol–Ene Chemistry

AbstractStructurally defined hyperbranched polymers (HBPs) bearing multiple azido peripheral groups and alkene dangling groups are constructed using the authors' recently developed chain‐growth copper‐catalyzed azide‐alkyne cycloaddition polymerization (CuAACP) of an alkene‐containing AB2 monomer. Sequential integration of CuAAC and photo‐initiated thiol–ene reactions proves highly efficient and chemo‐selective functionalization of polymers at different placements with quantitative yield of both reactive groups. A variety of HBPs carrying both surface and internal functionalities are then produced, achieving quantitative/ratiometric incorporations of guest molecules in most cases. To demonstrate possible conjugation with bioactive ingredients, well‐defined HBPs decorated with peripheral cysteine moieties are produced as an example, showing pH responsiveness in water.

Kinetic Study of the Polyaddition of Azide-Alkyne AB<sub>2</sub> Monomers in Nonisotermic Conditions

Nowadays, hyperbranched polymers (HBP) are obtained by different polycondensation and polyaddition reactions [1]. Almost interest is the reaction of 1,3-dipolar cycloaddition of azides to alkynes (1,3-DCA) [2, 3]. There is a series of papers dedicated to the preparation of triazine-triazole HBPs [4, 5, 6]. These polymers were obtained by the reaction of azido-acetylene AB2 monomers polyaddition: 2-azido-4,6-bis (propyne-2-yloxy) -1,3,5-triazine (ABPOT) and 2,4-diazido-6- (propine-2-yloxy) -1,3,5-triazine (DAPOT) (Fig. 1).

Designing Branched Deoxybenzoin Polyesters as Polymeric Flame Retardants

ABSTRACTAB2 monomers present opportunities to conduct one‐pot syntheses of highly branched or “hyperbranched” polymers, which are known for their distinct physical and chemical properties relative to linear polymers. This paper describes the synthesis of a deoxybenzoin‐containing AB2 monomer and its use in step‐growth polymerization to prepare branched aromatic polyesters. Highly soluble deoxybenzoin polymers were obtained with degrees of branching reaching 0.36 and estimated molecular weights approaching 20 kDa. The phenolic chain ends of the polymer allowed for post‐polymerization modification by silylation and esterification chemistry. TGA and microscale combustion calorimetry revealed these novel aromatic polyesters to possess the critically important characteristics of flame‐retardant polymers, such as high char yield and low heat release. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1765–1770

Chain‐growth polymerization of azide–alkyne difunctional monomer: Synthesis of star polymer with linear polytriazole arms from a core

ABSTRACTThis article reports a chain‐growth coupling polymerization of AB difunctional monomer via copper‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction for synthesis of star polymers. Unlike our previously reported CuAAC polymerization of AB n (n ≥ 2) monomers that spontaneously demonstrated a chain‐growth mechanism in synthesis of hyperbranched polymer, the homopolymerization of AB monomer showed a common but less desired step‐growth mechanism as the triazole groups aligned in a linear chain could not effectively confine the Cu catalyst in the polymer species. In contrast, the use of polytriazole‐based core molecules that contained multiple azido groups successfully switched the polymerization of AB monomers into chain‐growth mechanism and produced 3‐arm star polymers and multi‐arm hyperstar polymers with linear increase of polymer molecular weight with conversion and narrow molecular weight distribution, for example, Mw/Mn ~ 1.05. When acid‐degradable hyperbranched polymeric core was used, the obtained hyperstar polymers could be easily degraded under acidic environment, producing linear degraded arms with defined polydispersity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 84–90

SELECTIVE TARGETING OF AMYLOID-BETA OLIGOMER SPECIES BY PMN310, A MONOCLONAL ANTIBODY RATIONALLY DESIGNED FOR GREATER THERAPEUTIC POTENCY IN ALZHEIMER’S DISEASE

Advances in the understanding of Alzheimer's disease (AD) suggest that pathogenesis is not directly related to plaque burden, but rather to soluble toxic amyloid-beta oligomers (AßO). Therapeutic antibodies targeting Aß monomers and/or plaque have shown limited efficacy and dose-limiting adverse events in clinical trials. These findings suggest that antibodies capable of selectively neutralizing toxic AßO may achieve improved efficacy and safety. To this end, we generated a monoclonal antibody, PMN310, against a conformational Aß epitope predicted by computational modeling to be exposed on toxic AßO but not monomers or fibrils. The binding profile of PMN310 was characterized by surface plasmon resonance (SPR) and immunohistochemistry (IHC). Its ability to neutralize the propagation and toxicity of AßO was assessed in vitro in a thioflavin-T propagation assay and in cultures of primary rodent neurons, respectively. Protection against memory loss was tested in wild-type mice injected intracerebroventricularly with AßO. Brain exposure and kinetics were evaluated in aged wild-type mice and APP/PS1 transgenic mice. SPR analysis showed preferential binding of PMN310 to synthetic Ab oligomers vs monomers. Testing of soluble human AD brain extracts fractionated by size-exclusion chromatography consistently showed greater binding of PMN310 to the toxic oligomer-enriched low molecular weight fraction (<70 kDa) compared to aducanumab and bapineuzumab. IHC on frozen human AD brain sections showed no immunoreactivity of PMN310 with Aß deposits. In contrast, clear binding of parenchymal and vascular Aß was observed with aducanumab and bapineuzumab, consistent with the clinical occurrence of ARIA associated with these antibodies. In in vitro activity assays, PMN310 inhibited AßO propagation and neuronal toxicity. In vivo, PMN310 prevented AßO-induced loss of memory formation and reduced synaptic loss and inflammation. Systemic administration of PMN310 in mice resulted in brain exposure and kinetics comparable to those of other therapeutic human monoclonal antibodies. The greater selectivity of PMN310 for AßO and the potential to safely administer high doses with a reduced risk of ARIA suggest that it is likely to achieve greater therapeutic potency compared to other Aß-directed antibodies. Humanized PMN310 is currently in advanced preclinical development.

One-Stage High Temperature Catalytic Synthesis of Star-Shaped Oligoimides by (В4+АВ) Scheme

By the method of one-stage high-temperature polycondensation of 1,4-phenylene-bis-(5-oxy-1,3-phenylenediamine) (B4 monomer) with 4-(3-aminophenoxy)phthalic acid (AB monomer) in molten benzoic acid, four-arm star-shaped oligoimides with terminal amino groups were synthesized. Oligomers have a narrow molecular weight distribution (D = 1.2–1.3) and are soluble in organic solvents. The star-shaped oligoimides with terminal acetamide fragments were obtained by acylation of terminal amino groups with acetic anhydride.

Hyperbranched polymer–silver nanohybrid induce super antibacterial activity and high performance to cotton fabric

Herein we present a novel approach for synthesis, characterization and application of a benign hyperbranched polyester amide–silver nanohybrid (Ag/HBPEA). The Ag/HBPEA is developed through three distinct steps. The first step involves amidation reaction of diethanol amine and maleic anhydride to yield AB2 monomer (adduct 1). The second step comprises reaction of adduct 1 with trimethylol propane in presence of catalyst to yield HBPEA. The third step entails reduction of silver nitrate by sodium borohydride reductant to effect in situ formation of AgNPs which are stabilized by HBPEA, leading ultimately to Ag/HBPEA nanohybrid. Both Ag/HBPEA nanohybrid and HBPEA are independently applied to cotton fabrics as per the conventional pad-dry-cure technique. To this end, through investigations into the structures of Ag/HBPEA nanohybrid and HBPEA stabilizer before and after application to cotton fabric using advanced techniques emphasize the Ag/HBPEA nanohybrid as multifunctional finishing agent rather than a super antibacterial activity of the cotton fabrics after treatment with Ag/HBPEA nanohybrid speaks of this. Current research generally addresses green chemistry because treatments involved therein are based on green basics and practices.

Preparation and Evaluation of Antimicrobial Hyperbranched Emulsifiers for Waterborne Coatings.

Nosocomial infections are a major problem in medical health care. To solve this problem, a series of antimicrobial waterborne paints were prepared by using antimicrobial hyperbranched (HB) emulsifiers. The HB-emulsifiers were prepared by polymerizing AB2 monomers obtained in a one-step reaction of bis(hexamethylene)triamine and carbonyl biscaprolactam. The blocked isocyanate end groups (B groups) of the HB-polymer were utilized to introduce tertiary amino groups through the reaction with compounds comprising either a hydroxyl or a primary amino group and a tertiary amino group. Quaternization of the tertiary amines with 6 different alkyl bromides resulted in 12 amphiphilic cationic species. The 12 emulsifiers showed the successful inhibition and killing of 8 bacterial and 2 fungal strains. The killing efficacy increased with increasing alkyl chain length. The octyl-functionalized compound was chosen for suspension polymerizations because of the good compromise between killing and emulsifying properties. With this emulsifier, aqueous poly(methacrylate) suspensions were prepared, which were stable and had excellent killing properties.

Application of Glycerol in the Synthesis of Hyperbranched and Highly Branched Polyethers: Characterization, Morphology and Mechanism Proposal

Hyperbranched biopolymers is an important class of polymer that is used in different areas, mainly in biomedicine. AB2 monomers are crucial to the development of a architecture of polyglycerol, being glycidol the most commonly used, even considering its environmental hazard. Glycerol carbonate is an ecologically accepted monomer synthesized directly from glycerol, and the chosen for the studies herein. In literature, no studies described the use of glycerol and cyclic carbonates to prepare hyperbranched polymers. This work describes the obtainment of hyperbranched polymers using glycerol and TMP salt as core-initiator and glycerol carbonate and propylene carbonate as monomers. The polymers were characterized by FTIR, NMR, MALDI-TOF and TEM. NMR spectroscopy showed linear, dendritic, and terminal units of hyperbranched polymer. The degree of branching PGLYGC and PTMPGC was 0.669 and 0.667, respectively. The molecular weight of PTMCGC, PTMPPC, PGLYPC was found and compared with MALDI. The molar mass was not different from the calculated by Inverse Gated. These polymers have enormous potential as drug delivery and an environmentally correct synthetic route due to the substitution of glycidol by biocompatible monomers.