Hyperbranched Poly Ester Amide Research Articles

Fabrication of a highly hard yet tough epoxy nanocomposite coating by incorporating graphene oxide nanosheets dually modified with amino silane coupling agent and hyperbranched polyester-amide

This study aims to promote the epoxy systems' mechanical attributes (especially toughness) using surface-treated graphene oxide nanosheets. To this end, the graphene oxide nanoplatelets were synthesized and then surface-modified. 3-amino propyl triethoxy silane (APTES) and hyperbranched polyester amide (HBP) were employed via a serial approach. The results of different characterizing techniques (FTIR, TGA, XRD, Raman, and FE-SEM) approved the leading role of dual modification in expanding the inter-layer distance of nanoplatelets and significantly improving the filler dispersion within organic media. All unmodified and variously modified nanosheets were introduced into the epoxy at three loading levels (0.25, 0.5, and 1 wt%). While almost all modified nanoparticles could considerably enhance the hardness and toughness, the highest enhancement (2.6 times in toughness and 2.28 times in micro-hardness) was achieved with 1 wt% graphene oxide sequentially treated with APTES and HBP. Simultaneous promotion of hardness and toughness, which usually have an inverse relationship, was a highly desirable achievement. Our structural studies, utilizing the DMTA technique, revealed that such promotion was indebted to the simultaneous reinforcement in the physical (uniform filler distribution) and chemical (increased crosslinking density without any Tg elevation) aspects of the resultant network.

Chemo-mechanical modification of an acrylic melamine coating by the aid of a functional hyperbranched toughener to enhance its biological resistance

The main target of this paper is to promote the stability of a typical automotive clearcoat against biological materials such as bird dropping and tree gums. For this purpose, the acrylic/melamine matrix of clearcoat was chemically modified by a hyperbranched polyester-amide (HBP). Biological degradation was simulated with two different scenarios; pre-aging and post-aging. The viscoelastic and mechanical properties of various coatings were studied using dynamic mechanical thermal analysis (DMTA) and tensile experiments, respectively. The degradation was evaluated by FT-IR, gloss, color measurements and optical microscope. It was depicted that the intensity of degradation in post-aging approach was greater than pre-aging. The results demonstrated that an optimum addition of HBP, via improving the cross-linking density and mechanical properties (especially toughness), could considerably promote coating resistance against tree gum and bird dropping. In addition, it was shown that such improvement has been beholden to positive impact of HBP on bulk properties of the coating rather than changing its surface properties.

Theoretical and experimental investigation of mass transfer in aqueous two-phase systems based on linear and branched polymers

In this work the mass transfer of the amino acid, l-serine, in two different aqueous two phase systems (ATPS) was analysed. One ATPS is based on a hyperbranched polyesteramide and dextran T40 and the second one is formed by polyethylene glycol and dextran T40. The mass transfer was analysed experimentally and theoretically as well. The experimental analysis of the mass transfer was carried out in a Nitsch cell; whereas the mass transfer across the interface was modelled by the density gradient theory providing an expression for the chemical potential in the inhomogeneous region. As thermodynamic model the Lattice Cluster theory was used to account for the structure of the polymers. To consider the association, it was combined with a Wertheim approach. The mass transfer approach based on the density gradient theory was extended to a quaternary system for the first time and applied to model the mass transfer of l-serine in both ATPS. It was found that l-serine enriches at the interface during the mass transfer. The developed mass transfer approach was successfully applied to model the interfacial mass transfer of l-serine in both ATPS.

Interfacial Behavior of Aqueous Two-Phase Systems Based on Linear and Hyperbranched Polymers

In this work, the interfacial behavior of two different aqueous two-phase systems (ATPSs) was analyzed. One ATPS is formed by the dissolution of polyethylene glycol (PEG) and dextran T40 in water, and the second ATPS is formed by a hyperbranched polyesteramide (HB) and dextran T40. The interfacial behavior of both ATPSs was investigated experimentally and theoretically. As a thermodynamic model, the lattice cluster theory combined with a lattice Wertheim model was used. This thermodynamic model was combined with density gradient theory to model the interfacial properties. It was found that the interfacial tension, which was measured by the spinning drop method, of the ATPS containing the HB was lower than the interfacial tension of the ATPS containing the PEG. Moreover, the mass transfer of the phase forming components across the interface was measured and modeled. To measure the mass transfer, a Nitsch cell was used. The mass transfer was modeled by the instationary density gradient theory. It was found ...

Synthesis and spectroscopic properties of a new fluorescent acridine hyperbranched polymer: Applications to acid sensing and as antimicrobial agent

The synthesis of a hyperbranched polyesteramide functionalized with 6 acridine groups (P1000-ACRID) is described, and its photophysical properties compared with its low molecular weight reference compound (ACRIDyne). The hyperbranched polymer does not show aggregation of the acridine groups neither in solution nor in solid polymer matrices. The behavior of both chromophores as fluorescent acid sensors has been studied in solution and in solid polymer films, showing an increase in their fluorescence emission. The stoichiometry of the protonation reaction has been calculated, showing that ACRYDyne is able to protonate twice both in solution and in solid polymer matrices, whereas P1000-ACRID only protonates once. The sensing sensitivity of the compounds is consistent with this. The antimicrobial activity of the hyperbranched polymer has been tested against five bacteria (Gram positive and Gram negative) and two yeasts, showing high antimicrobial activity. The biocompatibility of low- and high-molecular weight compounds has been studied towards two mammalian cell lines (C2C12 and Swiss3T3), and the hyperbranched polymer shows higher biocompatibility than its low-molecular weight reference compound. P1000-ACRID allows enough cellular viability when used in its biofunctional concentration range.

Preparation and Characterization of Drug-Loaded Phthalic Anhydride Based Hyperbranched Polyesteramide Microspheres

This work was aimed to study the controlled drug delivery behavior of phthalic anhydride based hyperbranched polyesteramide (PA-HBPEA) synthesized by self-polycondensation method under nitrogen atmosphere. Drug-loaded microspheres were prepared by oil-in-water (o/w) emulsion solvent evaporation methodology using acetaminophen as a model drug and PA-HBPEA as the matrix. The polymer and microspheres were characterized by UV-Vis, FTIR and 1H NMR spectroscopy techniques. The morphology was observed by scanning electron microscopy (SEM) and optical microscopy. The drug loading capacity, drug entrapment efficiency, and percentage drug release were also measured by the UV-Vis spectroscopy. FTIR and NMR results confirmed the formation of drug-loaded PA-HBPEA microspheres. An in-vitro drug release study was carried out to understand the nature of transport of drug-containing solution through the polymeric material. The potential of high content of HBPEA formulation (HBPEA-M2) was controlled drug release more (up to 60.3%) than HBPEA-M1 (up to 76.8%) with acidic and phosphate buffer medium at 37°C at various time intervals. Drug release kinetics of zero order Higuchi and Korsmeyer – Peppas models were found to be satisfactory with exponent n > 0.6, which shows non-fickian diffusion release. The average size of microspheres was found to be 50 μm. In-vitro drug release data showed that HBPEA has potential of controlled drug release in phosphate buffer medium.

Drug structural features affect drug delivery from hyperbranched polyesteramide hot melt extrudates

The aim of this study was firstly to evaluate the utility of Hybrane S1200 as a hot melt extrusion (HME) carrier to prepare instant-release multiparticulate systems for very poorly-soluble drugs such as ketoconazole or nifedipine. Hybrane S1200 allows an easy extrusion of its drug mixtures at a relatively low temperature, not higher than 90°C, and with no need of any additional aid. Extrudates containing 10% of nifedipine or ketoconazole form monophasic systems. Nifedipine extrudate shows no drug release in drug dissolution rate tests while ketoconazole extrudate release reaches only 60% of drug content. Additionally, a turbidity in the dissolution medium due to the formation of a kind of polymer vesicles (ranging 3–0.2μm in size) is observed. These facts could suggest a chemical interaction between the polymer and both drugs, triggered by the HME process. Both nifedipine and ketoconazole share characteristic acid–base profiles that could facilitate a degradation processes within the polymer, thus modifying Hybrane’s water-solubility and polar nature. Such modified polymer structure, when in aqueous medium, forms the aforementioned stable vesicles that may encapsulate the drugs, thus making its delivery difficult or even preventing it.

Hyperbranched polymers as phase forming components in aqueous two-phase extraction

This work focusses on the experimental and theoretical investigation of the partitioning of a l-serine in an aqueous two-phase system (ATPS) based on a hyperbranched polymer. As a model ATPS, a polymer system containing a hyperbranched polyesteramide and dextran was chosen. The partitioning of l-serine in this ATPS was studied and compared with the partitioning of l-serine in a conventional ATPS consisting of polyethylene glycol (PEG) and dextran. For the thermodynamic modelling of these ATPS’s the Lattice Cluster Theory (LCT) in combination with the Wertheim association theory was used. The LCT allows the incorporation of the hyperbranched polymer architecture in the Helmholtz free energy and the Wertheim association theory considers the influence of the polar groups. As a result, it can be stated that in both ATPS, l-serine is mainly partitioned into the dextran-enriched phase, but in the ATPS based on the hyperbranched polyesteramide and dextran, the l-serine concentration in the dextran-enriched phase is higher. The partitioning of l-serine could be predicted by the used thermodynamic model on basis of the solubility experiments carried out for l-serine in aqueous solutions of phase forming components. Further, this work represents the first application of the used thermodynamic model on a quaternary system.

Drug dispersion degree and drug dissolution rate in Hybrane S1200-based instant-release matricial particles prepared by hot melt extrusion

The objective of this study is to evaluate the dissolution of a poorly soluble drug (prednisolone) from different sized matricial particles (from <250 to >1500 µm) with two drug contents (10% or 20%) obtained by hot melt extrusion using the hyperbranched polyesteramide Hybrane S1200 (water-soluble and with a Tg of 45 °C) as the carrier. X-ray diffraction, differential scanning calorimetry and SEM studies permit us to conclude that in 10% prednisolone extrudate, the drug is mainly dispersed within the carrier, whereas in those containing 20% an important fraction of the drug remains in a crystalline state and is accumulated on the surface of the extrudates. On particles proceeding from 10% drug extrudate, the drug dissolution rate is very high and slightly dependant on particle size and in all cases, higher than the pure micronized drug. However, on particles proceeding from 20% prednisolone extrudate particle size have a major effect on drug dissolution rate, attributable to higher proportions of crystalline drug accumulated on the surface, hindering polymer dissolution. Thus, the reduction of the particle size after extrudate grinding creates new surfaces from inside, that leads to strong increments on prednisolone dissolution rate, and becomes higher than the pure micronized drug one when the particle size is <250 µm.

Structure and Dynamics in Hydrophilic Polymer/Layered Silicate Nanocomposites

SummaryThe research efforts on the structure and dynamics of three different nanohybrid systems composed of hydrophilic polymers and layered silicates are summarized. A hydrophilic sodium montmorillonite, Na+‐MMT, is utilized as the inorganic material whereas three different polymers, poly(ethylene oxide), PEO, poly(hexa(ethylene glycol) methacrylate), PHEGMA, and a hyperbranched polyesteramide, Hybrane S 1200, were used in order of increasing complexity. In all cases, intercalated structures have been identified. We used quasi elastic neutron scattering, QENS, to investigate the effect of nanoconfinement on polymer dynamics by studying nanohybrids in which all polymer is confined within the inorganic galleries. The segmental dynamics in confinement are significantly influenced by the polymer‐surface interactions whereas the more local motions remain unaffected.

Novel aqueous two-phase system based on a hyperbranched polymer

Hyperbranched polymers have increased attention because of their branched structure and the wide range of different functional groups. Because of this feature hyperbranched polymers show an excellent applicability for aqueous two-phase systems (ATPS). In this work an ATPS consisting of a PEG-functionalized hyperbranched polyesteramide+water+Dextran T40 is compared to an ATPS consisting of PEG8000+Dextran T40+water. In addition to the experimental investigation of the ATPS, they will also be modeled using the lattice cluster theory (LCT) in combination with Wertheim theory. The LCT allows the direct incorporation of the polymer architecture in the Helmholtz free energy, so all derived properties are dependent on chain architecture. A multicomponent version of LCT for incompressible polymer solutions/blends is presented in this work. To consider associative interactions the LCT is combined with Wertheim association theory. To obtain the model binary interaction parameters of the hyperbranched polymer+water the subsystem hyperbranched polymer+water was experimentally estimated, and for the subsystem PEG8000–water experimental data from literature were used, the parameters were fitted in both cases. So both ATPS could be modeled. In addition to the phase behavior, the kinematic viscosity of both ATPS was compared.

4-Dimethylaminopyridine Promoted Interfacial Polymerization between Hyperbranched Polyesteramide and Trimesoyl Chloride for Preparing Ultralow-Pressure Reverse Osmosis Composite Membrane

We have presented a concept of ultralow-pressure reverse osmosis membrane based on hyperbranched polyesteramide through interfacial reaction promoted by pyridine derivate. In this strategy, a key catalyst of 4-dimethylaminopyridine, which can both eliminate the steric hindrance of acyl transfer reaction and facilitate the phase transfer in interfacial polymerization, is adopted to drive the formation of a thin film composite membrane from the hyperbranched polyesteramide and trimesoyl chloride. The results of the characterization demonstrate that a dense, rough, and hydrophilic active layer with a thickness of about 100 nm is formed when the 4-dimethylaminopyridine catalyst is used. The salt rejections for Na2SO4, NaCl, and MgSO4 of the as-prepared composite membrane are higher than 92%, especially for Na2SO4 with 98% rejection. The water fluxes reach about 30-40 L·m(-2)·h(-1) even at an operation pressure of 0.6 MPa. The membrane exhibits good chlorine-resistance ability but poor resistance abilities to acidic and alkaline solutions in the physical-chemical stability experiment. It is also found that the resultant membrane possesses excellent separation performance for PEG-200, showing a promising way to separate small organic molecules from water.

Structure and Dynamics of Hyperbranched Polymer/Layered Silicate Nanocomposites

The structure and dynamics of a hyperbranched polyesteramide (Hybrane S 1200) polymer and its nanocomposites with natural montmorillonite (Na+–MMT) are investigated to offer a detailed picture of its behavior in bulk and under confinement. In bulk, the behavior is probed by quasi-elastic neutron scattering (QENS) with molecular dynamics simulations employed for a better insight into the relevant relaxation processes. The energy-resolved elastically scattered intensity from the polymer exhibits two distinct relaxation steps, one attributed to sub-Tg motions and one observed at temperatures above the glass transition, Tg. The QENS spectra measured over the complete temperature range are consistent with the elastic measurements and can be correlated to the results emerging from the detailed description afforded by the atomistic simulations, which cover a broad time range and predict the existence of three relaxation processes. The nanocomposites are investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and QENS. XRD reveals an intercalated nanocomposite structure with the polymer chains residing within the galleries of the Na+–MMT. The polymer chains confined within the galleries show similarities in the behavior with that of the polymer in the bulk for temperatures below the bulk polymer Tg, whereas they exhibit frozen dynamics under confinement at temperatures higher than that.

Thermomechanical and chemorheology properties of a thermosetting acrylic/melamine clearcoat modified with a hyperbranched polymer

The work presented here aims at studying the thermomechanical and chemorheological properties of an automotive clearcoat containing an acrylic/melamine resin modified with a hyperbranched poly ester-amide (HBP) additive. Rheological experiments were conducted at ambient (25°C) and curing temperature (140°C). Dynamic mechanical thermal analysis and hardness measurements were performed to reveal the influence of HBP content on the behavior of the cured samples. It was found that the viscosity of the resin containing HBP samples considerably decreased. Although curing degree and mechanical properties were improved at low HBP loadings, a reverse effect was seen at higher contents. Dynamic rheological results during curing showed that although low amount of HBP resulted in an early gel point (GP), higher HBP loading postponed the GP. This loading-dependent behavior was explained by the influence of HBP on viscosity and reactivity of the system on which the curing performance was influenced oppositely. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Modification of cement with succinic anhydride-based hyperbranched polyesteramide

Two hyperbranched polyesteramides (HYP1 and HYP2) were prepared by reacting succinic anhydride (ScAn) with both of diisopropanolamine (DiPA) and diethanolamine, respectively, via one-pot polycondensation reaction. The prepared polymers were analyzed using gel permeation chromatography, infrared spectra, and 1HNMR. The resulting hydroxyl-ended resins have been successfully applied as polymeric admixtures in two types of cements such as Ordinary Portland cement and Portland limestone cement. The water of consistency decreased by addition of the hyperbranched polymers in both types of cements. Better hydration was observed by incorporation of small amounts of polymers. The infrared spectra and scanning electron microscopy photos of Ordinary Portland cement and Portland limestone cement pastes premixed with HYP1 and HYP2 showed no effect on the chemical composition of the cement hydrates where only the morphology and the crystallinity of the formed hydrates were changed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Effect of phthalic anhydride‐based hyperbranched polyesteramide on cement characteristics

AbstractHyperbranched polyesteramides (HB1 and HB2) were prepared by the bulk reaction between phthalic anhydride (PhAn) with either diisopropanolamine (DiPA) or diethanolamine (DEA), respectively. The hyperbranched polyesteramides were characterized by IR, GPC, 1H‐NMR, and thermal analysis (TGA and DSC). The effects of solutions of 1, 3, and 5 wt % HB1 and HB2 on the properties of Ordinary Portland Cement (OPC) and Portland Limestone Cement (PLC) were studied. Measurements of water of consistency, setting times, bulk density, apparent porosity, and compressive strength for the cement pastes were performed. Some selected cement pastes were characterized by IR and SEM photos. The results showed that HB1 and HB2 slightly increased the compressive strength, the combined water and density while decreased the apparent porosity. IR of the formed phases showed increase in the intensities of the spectra for the cement pastes mixed with HB1 and HB2 when compared with those of the blank cement pastes. SEM images showed that the incorporation of HB1 and HB2 affected only shape or morphology and crystallinity of the formed hydrates. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Modification of Some Hyperbranched Polyols with Oligo (Ethyleneoxide) Units on the Way to New Applications

Three different hyperbranched polymers (H1, H2, and H3) were prepared. The H1 and H2 are hyperbranched polyesteramide polymers; however, H3 is a poly(urea-urethane) hyperbranched polymer. The three polymers were treated with Br-ended surfactant units, which were prepared via simple reaction of Tergitol Np-50 (S) as surfactant with bromoisobutyrylbromide. New ended polymers resulted as H1S, H2S, and H3S with new ethyleneoxide units. Critical micelle concentration (CMC) was studied for the newly prepared polymers (H1S, H2S, H3S) and was compared with the original ones (H1, H2, H3) on the way to involve the new modified polymers in various industrial applications. The CMC was determined by the surface tension technique employing the platinum ring method. It was found that CMC could be arranged in the following ascending order: H3S < H2S < H1S < H3 < S < H2 < H1.

Dielectric Properties of Hyperbranched Polyesteramide with Long Alkyl Chain End Groups

AbstractSummary: Hyperbranched polyesteramides were prepared using phethalic anhydride (Ph An) or maleic anhydride (M An) as an A2 monomer and diethanol amine (DEA) as B′B2 monomer. Bulk condensation technique was used to synthesize polymers with both OH and modified polymers with long alkyl chain end groups. The prepared polymers were characterized using 1H‐NMR, FTIR and TGA. Solution viscosity for hyperbranched polyester amide with hydroxyl end groups was measured as well. Dielectric and electric properties of the modified samples were investigated over a range of frequency and temperatures. No relaxation peak is noticed in the dielectric spectrum ε(ν) at various temperatures. The illustration of the imaginary part of the electric modulus M″ versus frequency shows a peak which is shifted towards higher frequency in increasing temperature.

Dielectric Properties of Hyperbranched Polyesteramide with Long Alkyl Chain End Groups

Dielectric Properties of Hyperbranched Polyesteramide with Long Alkyl Chain End Groups

Preparation, characterization and modification of hyperbranched polyester-amide with core molecules

The synthesis of hyperbranched polyester-amides based on pentaerythritol (PETL) as a core molecule and AB 2 monomer containing one carboxylic group and two hydroxylic groups using core-dilution/slow monomer addition strategy have been studied. The AB 2 monomer was prepared by diisopropanolamine (DIPA) and cis-1,2-clyclohexane-dicarboxylic anhydride (HHPA). Two types of hyperbranched polyester-amide (1G-HP, 2G-HP) were obtained with the molar ratio of AB 2 monomer and pentaerythritol (PETL) was 4 and 8, respectively. The structures of products were characterized by IR, 13C NMR, GPC and viscosity measurement. It was shown that the hyperbranched polymers prepared had high degree of branching (DB) and narrow molecular weight distribution. As for 1G-HP and 2G-HP, the intrinsic viscosity [ η] was 4.32 ml/g and 5.29 ml/g, and the viscometric radius R V was1.28 nm and 1.67 nm, respectively. The results of viscosity measurement indicated that the structures of 1G-HP and 2G-HP were compacted and had a spherical conformation. In addition, the reactions of hydroxyl end-groups with polyethylene glycol monomethyl ether (mPEG550) and glycidyl methacrylate (GMA) were conducted to provide amphiphilic and UV-curable properties of resulting polymers. The properties of the modified hyperbranched polyester-amide were also investigated initially.