Synthesis Of Hyperbranched Poly Research Articles

Synthesis of hyperbranched poly(ether nitrile)s as supporting polymers for palladium nanoparticles

A novel hyperbranched poly(ether nitrile) (HBPEN) and its copolymer were synthesized as supports for palladium nanoparticles (PdNPs). Small PdNPs (3.0±0.8 nm) were obtained by the reduction of HBPEN-Pd2+ complex with NaBH4. A comparison of HBPEN-, HBPEN copolymer- and linear poly(ether nitrile)-supported PdNPs suggested that the branched architecture in HBPEN can help prevent the aggregation of PdNPs generated in the early stages of reduction.

Hyperbranched poly(N-(2-hydroxypropyl) methacrylamide) via RAFT self-condensing vinyl polymerization

We report the first synthesis of hyperbranched poly(N-(2-hydroxypropyl) methacrylamide) (HB-PHPMA) using reversible addition–fragmentation chain transfer (RAFT) self-condensing vinyl polymerization (SCVP).

Synthesis of hyperbranched poly(amidoamine) conjugated silica (HBPcS) particles and their application to colorimetric detection of cadmium ion

Hyperbranched poly(amidoamine) conjugated silica (HBPcS) particles were synthesized by grafting poly(amidoamine) dendrimers on multiple-functional hybrid silica (MHS) particles containing three different organosilane functional groups. Due to advantageous combination of dendrimers, with ample and controlled amount of amine groups, and monodisperse and stable MHS particles from simple one-pot synthesis, the HBPcS particles can serve as multifunctional platforms for various applications. The growth of the amine functional groups of the HBPcS particles with the generation number was confirmed by monitoring the amide peaks in IR spectra as well as indirectly by monitoring the amount of the molecules that are bound to the functional groups. As a proof of principle, colorimetric sensors for Cd ions were prepared by employing the HBPcS particles and organic Cd ion sensing molecules. Notably, the sensor particles from HBPcS particles of different generations showed different detection ranges due to the increase in the amount of amine functionalities by grafting processes.

Synthesis of hyperbranched poly(ethyleneimine) based macromolecular antioxidants and investigation of their efficiency in stabilization of polyolefins

Macromolecular antioxidants with highly suppressed leaching to the environment, based on hyperbranched poly(ethyleneimine) carrier with bonded sterically hindered phenol and alkyl compatibilizing groups with various chain length were synthesized and tested for their efficiency in stabilization of polyolefins. The synthesis of the macromolecular antioxidants was carried out by amidation of the amine groups present in poly(ethyleneimine) with various carboxylic acids containing sterically hindered phenol and compatibilizing groups, such as n-butyryl, lauryl or stearyl. The structure of the resulting polymers was analyzed by 1H NMR and by GPC. The antioxidant content of the samples was determined by UV–Vis spectroscopy. The efficiency of the synthesized antioxidants in thermooxidative stabilization of polypropylene was determined by chemiluminescence. The efficiency in photostabilization of polypropylene and polyethylene was investigated by using FT IR and UV–Vis spectroscopies. It was found that the macromolecular antioxidant which did not contain any compatibilizing groups shows the best stabilizing efficiency in both thermooxidative and photooxidation tests. The extent of extraction of the synthesized macromolecular antioxidants from polypropylene films was investigated as well. Low extent of extraction of the macromolecular antioxidants from the polypropylene films was observed in contrast to the high level of leaching of commercially used low molecular weight phenolic antioxidant. These results indicate the environmental advantage of the investigated poly(ethyleneimine) based macromolecular antioxidants over the widely applied low molecular weight compounds.

One‐pot synthesis of hyperbranched poly(aryl ether ketone)s for the modification of bismaleimide resins

Hyperbranched poly(aryl ether ketone)s with hydroxyl end groups (HBP‐OH) and high degree of branching value (83%) were synthesized via an A2 + B3 approach. The polymerization conditions (e.g., polymerization temperature and time, monomer concentration, stoichiometric ratio of functional groups) were explored to avoid the gelation. Allyl‐terminated hyperbranched PAEKs (HBP‐AL) with low molecular weight (Mn = 3.4 × 103) and narrow polydispersity (PDI = 1.65) were obtained via the etherification of HBP‐OH and it has been used for the modification of bismaleimide (BMI) resins. The prepolymers showed good processibilities with a viscosity below 0.6 Pa s at 110°C, though the viscosities slightly increased as the increase of HBP‐AL contents. The cured BMI resins showed high glass transition temperatures (Tg > 320°C) and good thermal stabilities (Td > 400°C, both in nitrogen and air). It is inspiring to note that the incorporation of HBP‐AL into BMI matrix results in a significant enhancement of toughness without any noticeable loss in modulus, processibility, and Tg. POLYM. ENG. SCI., 54:1675–1685, 2014. © 2013 Society of Plastics Engineers

The synthesis of hyperbranched poly (amine-ester) and study on the properties of its UV-curing film

Firstly, the monomer of N, N-diethylol-3-amine methylpropionate was obtained via Michael addition of methyl acrylate and diethanolamine. Then the hyperbranched poly (amine-ester) (HBPE) was synthesized through pentaerythritol as core molecules and monomer as AB2. HBPE was characterized by Fourier transform-infrared spectroscopy, hydrogen nuclear magnetic resonance (1H-NMR) and elemental analysis. Methyl tetrahydrophthalic anhydride (MTHPA) is grafted to the hydroxyl groups of HBPE and then glycidyl methacrylate (GMA) is introduced to the structure of HBPE, which is obtained by the UV-curable hyperbranched prepolymer (HBPE-MTHPA-GMA). Ultraviolet-differential scanning calorimeter showed that the HBPE-MTHPA-GMA has high photocuring speed under photoinitiator. Furthermore, the films also show good impact strength, outstanding adhesive force and primary thermal stability.

Hyperbranched PEG by Random Copolymerization of Ethylene Oxide and Glycidol

The synthesis of hyperbranched poly(ethylene glycol) (hbPEG) in one step was realized by random copolymerization of ethylene oxide and glycidol, leading to a biocompatible, amorphous material with multiple hydroxyl functionalities. A series of copolymers with moderate polydispersity ($\overline {M} _{{\rm w}} /\overline {M} _{{\rm n}} $ < 1.8) was obtained with varying glycidol content (3-40 mol-%) and molecular weights up to 49 800 g mol(-1) . The randomly branched structure of the copolymers was confirmed by (1) H and (13) C NMR spectroscopy and thermal analysis (differential scanning calorimetry). MTS assay demonstrated low cell toxicity of the hyperbranched PEG, comparable to the highly established linear PEG.

One-pot synthesis of hyperbranched poly(amido amine) clicked with a sugar shell via Michael addition polymerization and thiol click reaction

This paper reports the production of glycopolymers via a simple and flexible method. A novel glycopolymer with a hyperbranched poly(amido amine) core and a sugar shell (HPAA-GLc) was synthesized by using thiol-ene click reaction via facile one-pot method. Hyperbranched poly(amido amine) with vinyl terminals was first synthesized by Michael addition polymerization of N,N′-methylene bisacrylamide (MBA) with 1-(2-aminoethyl) piperazine (AEPZ). Subsequently, thiol-ene click reaction between vinyl units of hyperbranched poly(amido amine) and thio-glucose was performed in situ. Based on the NMR result, all the vinyl groups reacted with thiol-glucose in 120 min. Strong photoluminescence emission was observed from the aqueous solution of HPAA-GLc.

Synthesis of hyperbranched poly(3‐methyl‐3‐hydroxymethyloxetane) and their application to separate basic proteins by adsorption coated column

AbstractA series of hyperbranched poly(3‐methyl‐3‐hydroxymethyloxetane)s with different degree of branching were synthesized using BF3·OEt2 as initiator and coated on the inner surface of the fused‐silica capillaries. In the pH range of 3–9, the coated capillaries reduced electro‐osmotic flow by about four times lower than the bare fused‐silica capillary. The coated capillaries also displayed good resistance to adsorption of cationic proteins, providing clean separations of a mixture of Lysozyme, Cytochrome c, and Ribonuclease A around pH 3–6 in phosphate buffer. The separation efficiency in terms of peak shape was excellent compared with bare fuse‐silica capillary. The separation efficiency of hyperbranched poly(3‐methyl‐3‐hydroxymethyloxetane) with degree of branching of 0.43‐coated capillary column for Lysozyme reached 106 plates/m with a resolution of 7.1, and the coated capillary column had good migration time reproducibility. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis of hyperbranched poly(ether nitrile)s by one-step polycondensation of an AB2 monomer

Hyperbranched poly(ether nitrile)s were prepared from a novel AB2 type monomer, 2-chloro-4-(3,5-dihydroxyphenoxy)benzonitrile, via nucleophilic aromatic substitution. Soluble and low-viscous hyperbranched polymers with molecular weights upto 233,600 (Mw) were isolated. According to the 1H NMR and GPC data, the unique polymerization behavior was observed, which implies that the weight average molecular weight increased after the number average molecular weight reached plateau region. Model compounds were prepared to characterize the branching structure. Spectroscopic measurements of the model compounds and the resulting polymers, such as 1H, DEPT 13C NMR, and MS, strongly suggest that the ether exchange reaction and cyclization are involved in the propagation reaction. The side reactions would affect the unique polymerization behavior. The resulting polymers showed a good solubility in organic solvents similar to other hyperbranched aromatic polymers. The hydroxy-terminated polymer was even soluble in basic water. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5835–5844, 2009

Self‐controlled synthesis of hyperbranched poly(ether‐ketone)s from A2 + B3 approach in poly(phosphoric acid)

AbstractSelf‐controlled synthesis of hyperbranched poly(ether‐ketone)s (HPEKs) were prepared from “A2 + B3” approach by using different monomer solubility in reaction medium. 1,3,5‐Triphenoxybenzene as a hydrophobic B3 monomer was reacted with commercially available terephthalic acid or 4,4′‐oxybis(benzoic acid) as a hydrophilic A2 monomer in a hydrophilic reaction medium, polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5). The resultant HPEKs were soluble in various common organic solvents and had the weight‐average molecular weight in the range of 3900–13,400 g/mol. The results implied that HPEKs were branched structures instead of crosslinked polymers. The molecular sizes and shapes of HPEKs were further assured by morphological investigation with scanning electron microscopy (SEM) and atomic force microscopy (AFM). Hence, the applied polymerization condition was indeed strong enough to efficiently facilitate polycondensation via “direct” Friedel‐Crafts reaction without gelation. It could be concluded that the polymer forming reaction was kinetically controlled by automatic and slow feeding of the hydrophobic B3 monomer into the hydrophilic reaction mixture containing hydrophilic comonomer. As a result, hyperbranched structures were formed instead of crosslinked polymers even at full conversion (equifunctional monomer feed ratio). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3326–3336, 2009

Hyperbranched Polytriazoles: Click Polymerization, Regioisomeric Structure, Light Emission, and Fluorescent Patterning

Synthesis of hyperbranched poly(1,2,3-triazole)s (hb-PTAs) has been a challenge: the AB2 monomers were inclined to self-oligomerize, and their Cu(I)-catalyzed click polymerizations failed to yield soluble polymers. We tackled the challenge in this work and succeeded in generating hb-PTAs with regioregularity, processability, and functionality. We took an A2 + B3 approach and used diazides 2 and triyne 3 as monomers, which are free of self-oligomerization concerns. Thermal polymerizations of 2 and 3 produced regiorandom polymers (hb-r-P1) with high molecular weights in high yields. Metal-mediated regioselective polymerizations afforded soluble 1,4- and 1,5-linked polymers (hb-1,4-P1 and hb-1,5-P1), presenting the first examples of regioregular hb-PTAs with macroscopic processability. The reactions were affected by substrate and catalyst: electron-rich alkyne generally slowed down the cycloaddition reaction, while ruthenium catalysts (Cp*Ru(PPh3)2Cl and [Cp*RuCl2]n) exhibited higher substrate tolerance than...

Synthesis of hyperbranched poly(aryl amine)s via a carbene insertion approach

A novel diazirine functionalised aniline derivative, 3-(3-aminophenyl)-3-methyldiazirine 1, was prepared and employed as an AB(2)-type monomer in the synthesis of hyperbranched polymers; thus providing the first instance in which polyamines have been prepared via carbene insertion polymerisation. Photolysis of the monomer 1 in bulk and in solution resulted in the formation of hyperbranched poly(aryl amine)s with degrees of polymerisation (DP) varying from 9 to 26 as determined by gel permeation chromatography (GPC). In solution, an increase in the initial monomer concentration was generally found to result in a decrease in the molecular weight characteristics of the resulting poly(aryl amine)s. Subsequent thermal treatment of the poly(aryl amine)s caused a further increase in the DP values up to a maximum of 31. Nuclear magnetic resonance (NMR) spectroscopic analysis revealed that the increase in molecular weight upon thermal treatment resulted from hydroamination of styrenic species formed in the initial photopolymerisation or activation of diazirine moieties.

Influence of reaction parameters on the synthesis of hyperbranched polymers via reversible addition fragmentation chain transfer (RAFT) polymerization

The synthesis of hyperbranched poly(methyl methacrylate) (PMMA) via reversible addition fragmentation chain transfer (RAFT) polymerization was investigated by varying the ratio chain transfer agent (CTA): monomer (methyl methacrylate, MMA): brancher (ethylene glycol dimethyl methacrylate, EGDMA): free radical initiator (AIBN) at various temperatures (50, 55, 60, 65, 70 °C). The rate of polymerization was observed to increase with temperature and concentration in brancher, whilst it was lowered by an increase in chain transfer agent concentration. The molecular weight of the samples increased with the ratios brancher: CTA and monomer: CTA. The polydispersity of the samples increase with conversion, as the level of branching increases. At fixed concentration in brancher, an increase of CTA concentration led to polymers with lower PDI. The variation of enthalpy ( Δ H ¯ m ) and entropy ( Δ S ¯ m ) relative to the monomer reaction were calculated, and it was observed that an increase in the brancher concentration induced an increase in both Δ H ¯ m and Δ S ¯ m , whilst lower CTA concentrations led to an increase in Δ S ¯ m . The variation in Gibbs energy for the monomer reaction ( Δ G ¯ m ) was calculated at 60 °C, and results confirmed the presence of a retardation effect when increasing CTA concentration generally observed in RAFT polymerization.

Synthesis of hyperbranched poly(amine–ester)-protected noble metal nanoparticles in aqueous solution

The synthesis of Au and Ag metal nanoparticles stabilized by G4, G5, and G6 hyperbranched poly(amine–ester) (HPAE) is reported. The reduction of hydrogen tetrachloroaurate and silver nitrate in the presence of HPAE resulted in the formation of stable, uniform, water-soluble nanoparticles. The average particle sizes are (2.4 ±0.5)–(4.1 ±0.4) nm for Au and (2.5 ±4.9)–(10.3 ±1.7) nm for Ag, depending on the generation of HPAE and metal ion-to-end tertiary amine of HPAE (M:N) used. All of the obtained colloidal solutions are stable for a long period of time. The results from ultraviolet–visible absorption spectra and Fourier transform infrared absorption spectroscopic investigations confirm the interactions between metal and HPAE.

Effect of Core Reactivity on the Molecular Weight, Polydispersity, and Degree of Branching of Hyperbranched Poly(arylene ether phosphine oxide)s

Synthesis of hyperbranched poly(arylene ether phosphine oxide)s, HB PAEPOs, from bis(4-fluorophenyl)(4-hydroxyphenyl)phosphine oxide, 1a, in the presence of a series of core molecules with systematically altered reactivity of the aryl fluoride groups provides polymers with molecular weights, MWs, controlled by the concentration of the core molecule, and narrow polydispersity indices, PDIs. Polymers with number-average molecular weights ranging from 3270 to 8100 Da, and PDIs as low as 1.25 have been prepared. The core molecules utilized in this work consist of a series of fluorinated triarylphosphine oxides, tris(4-fluorophenyl)phosphine oxide, tris(3,4-difluorophenyl)phosphine oxide, and tris(3,4,5-trifluorophenyl)phosphine oxide, 2a, 2b, and 2c, respectively. The most highly activated core, 2c, provides the best control over the final MW and the lowest PDIs. The degree of branching, DB, for the HB PAEPOs decreases from 0.57 with no core to below 0.40 at higher concentrations of 2b and 2c.

Synthesis of hyperbranched poly(tert-butyl acrylate) by self-condensing atom transfer radical polymerization of a macroinimer

Using 2-hydroxyethyl α-bromoisobutyrate as initiator, atom transfer radical polymerization (ATRP) of tert-butyl acrylate leads to poly(tert-butyl acrylate) (PtBA) with a hydroxyl group at one and a bromine atom at the other end. Esterification of the hydroxyl group of these heterotelechelic polymers with acryloyl chloride yields PtBA (Mn = 3 060) with a polymerizable double bond at one end and a bromine atom at the other end which can act as an initiator in ATRP (“macroinimer”). Self-condensing ATRP of such a macroinimer leads to hyperbranched or highly branched PtBA. The polymer was characterized by GPC viscosity measurements. Even at Mw = 78 800, a rather low polydispersity index of Mw/Mn = 2.6 was obtained. A significantly lower value for the Mark-Houwink exponent (α = 0.47 compared to α = 0.80 for linear PtBA) indicates the compact nature of the branched macromolecules.