Structural and Interfacial Properties of Hyperbranched-Linear Polymer Surfactant

With oleic acid grafting modification, a series of hyperbranched-linear polymer surfactants (HLPS) were prepared by hydroxyl-terminated hyperbranched polymer (HBP), which was gained through a step synthesis method using trimethylolpropane and AB₂ monomer. The AB₂ monomers were obtained through the Michael addition reaction of methyl acrylate and diethanol amine. The structures of HLPS were characterised by Fourier transform infrared spectrophotometer and nuclear magnetic resonance (NMR), which indicated that HBP was successfully modified by oleic acid. Furthermore, the properties of surface tension and critical micelle concentration of HLPS solution showed that HLPS can significantly reduce the surface tension of water. The morphology of the HLPS solution was characterised by dynamic light scattering, which revealed that HLPS exhibited a nonmonotonic appearance in particle size at different scattering angles owing to the different replaced linear portions. The relationships of the surface pressure to monolayer area and time were measured using the Langmuir–Blodgett instrument, which showed that the surface tension of monolayer molecules increased with the increasing of hydrophobic groups. In addition, the interface conditions of different replaced HLPS solutions were simulated.     

超支化聚酯的端基改性及其涂膜性能

以三羟甲基丙烷为核多元醇,二羟甲基丙酸为AB₂型单体,对甲苯磺酸为催化剂准一步法合成了第二代超支化聚酯(HBP-0)。HBP-0分别经己内酯和月桂酸改性得到改性超支化聚酯(HBPs)。采用FT-IR、¹H NMR和GPC对HBP-0的结构和相对分子质量进行表征,发现超支化聚酯的支化度为0.43,相对分子量与理论相对分子量比较接近, 相对分子质量分布系数只有1.72。以甲苯二异氰酸酯加成物为交联剂,考察了改性超支化聚酯交联涂膜性能,结果表明,3种改性超支化聚酯的涂膜性能在光泽度、耐冲击性、附着力和柔韧性方面表现十分优异。其中HBP-3同时用己内酯和月桂酸改性具有最佳性能,黏度最低为7500 mPa·s,涂膜表干40 min,且硬度达到F。而单独用己内酯或月桂酸改性的HBP-1和HBP-2的相应数据分别为7×10⁵ mPa·s、20 min和HB及17500 mPa·s、90 min和2B。     

Synthesis and characterization of hyperbranched aromatic poly(ester-imide)s

The synthesis and characterization of hyperbranched aromatic poly(ester-imide)s are described. A variety of AB₂ monomers, N-[3- or 4-bis(4-acetoxyphenyl)toluoyl]-4-carboxyl-phthalimide and N-{3- or 4-[1,1-bis(4-acetooxyphenyl)]ethylphenyl}-4-carboxy phthalimides were prepared starting from condensation of nitrobenzaldehydes or nitroacetophenones with phenol and used for synthesis of hyperbranched poly(ester-imide)s containing terminal acetyl groups by transesterification reaction. These hyperbranched poly(ester-imide)s were produced with weight-average molecular weight of up to 6.87 g/mol. Analysis of ¹H NMR and ¹³C NMR spectroscopy revealed the structure of the four hyperbranched poly(ester-imide)s. These hyperbranched poly(ester-imide)s exhibited excellent solubility in a variety of solvents such as N,N-dimethylacetamide, dimethyl sulfoxide, and tetrahydrofuran and showed glass-transition temperatures between 217 and 255 °C. The thermogravimetric analytic measurement revealed the decomposition temperature at 10% weight-loss temperature (T_d¹⁰) ranging from 365 to 416 °C in nitrogen.     

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.     

Linear-hyperbranched copolymerization as a tool to modulate thermal properties and crystallinity of a para-poly(ether-ketone)

The AB₂ monomer, 3,5-bis(4-fluorobenzoyl)phenol was synthesized via an improved four-step scheme. It was polymerized to form the corresponding fluoride-terminated hyperbranched polymer with higher molecular weight than previously reported, as evidenced by higher glass-transition temperature (T_g=159 °C vs. 140-143 °C). The homopolymerization showed a bimodal molecular weight distribution that was also observed for other related linear-hyperbranched systems. The AB₂ monomer was then copolymerized with 4-fluoro-4′-hydroxybenzophenone (AB monomer), in weight ratios of 1:3, 1:1 and 3:1 to afford the respective hyperbranched poly(ether-ketones) with variable degrees of branching. The 1:1 copolymer had T_g value (212 °C) that was significantly (35 °C) higher than both linear and hyperbranched homopolymers. Only the 1:3 copolymer was semi-crystalline, displaying melting at 340 °C and its wide angle X-ray scattering (WAXS) pattern indicated that its crystal structure is exactly the same as that of the linear homopolymer. The WAXS results of the copolymers correlated well with differential scanning calorimetry and themogravimetric analysis results.     

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 AB₂ monomer containing one carboxylic group and two hydroxylic groups using core-dilution/slow monomer addition strategy have been studied. The AB₂ 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 AB₂ 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.     

In situ grafting of carboxylic acid-terminated hyperbranched poly(ether-ketone) to the surface of carbon nanotubes

Carboxylic acid-terminated hyperbranched poly(ether-ketone)s (HPEKs) were successfully grafted onto the surfaces of single-walled carbon nanotube (SWNT) and multi-walled carbon nanotube (MWNT) to afford HPEK-g-SWNT and HPEK-g-MWNT nanocomposites. They were prepared via in situ polymerization of 5-phenoxyisophthalic acid as an AB₂ monomer for the HPEK in the presence of SWNT or MWNT in polyphosphoric acid (PPA)/phosphorous pentoxide (P₂O₅) medium. The resultant nanocomposites were homogeneously dispersed in various common polar aprotic solvents as well as in concentrated ammonium hydroxide. The experimental results from Soxhlet extraction, solubility enhancement, elemental analysis (EA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) provided clear evidences for grafting of hyperbranched polymers onto the surfaces of corresponding CNT's. Achieving enhanced solubility of CNT's in common organic solvents via the functionalization of CNT's is a key step for CNT's to be used in various application-specific purposes. The results could potentially envision to the area of CNT researches via the efficient introduction of three-dimensional globular dendritic macromolecules as increasing solubility, available multi-functionality, reactivity, processability, and also biocompatibility.     

Synthesis, optical and electrochemical properties of new hyperbranched poly(triphenylamine amide)s

A new triphenylamine-containing AB₂ type monomer with one carboxylic acid and two amino groups, 4-(bis(4-aminophenyl)amino)benzoic acid (3), was synthesized and used for the preparation of hyperbranched poly(triphenylamine amide)s. The self-polycondensation of the AB₂ monomer (3) afforded hyperbranched poly(triphenylamine amide) with amino end groups. The molecular weight of the hyperbranched poly(triphenylamine amide) was 21,000 Da determined by light scattering. End-capped hyperbranched polyamides were isolated by the chemical modification of unreacted amino groups with various acid chlorides. All the hyperbranched poly(triphenylamine amide)s exhibit excellent solubility in organic solvents such as NMP, DMF, DMSO, and DMAc at room temperature. The viscosities of hyperbranched poly(triphenylamine amide)s are as low as about 0.15 dL/g due to their dendritic structures. Poly(triphenylamine amide)s end-capped with rigid benzene ring have higher thermal stability than those with amino or aliphatic end groups. The photoluminescence of the hyperbranched polyamides is blue-yellow emissions around 430-510 nm. The energy gaps of the hyperbranched poly(triphenylamine amide)s with different end groups are about 2.93 eV and are independent on the end groups, but the HOMO and LUMO energy levels are dependent on the end groups.     

Preparation of epoxy‐ended hyperbranched polymers with precisely controllable degree of branching by thiol‐ene Michael addition

Epoxy‐ended hyperbranched polymers (EHPs) have a wide range of applications due to their outstanding performances. Because their microstructures are not positively identified, it is very difficult to ascertain the reinforcing and toughening mechanisms of EHPs and their interface interaction with other matrixes. Controllable synthesis of EHPs with precise degree of branching (DB) remains to be a major challenge. Here, a method for preparing novel nitrogen‐phosphor skeleton epoxy‐ended hyperbranched polymers (NPEHP) with controllable DB by a thiol‐ene Michael addition between thiol‐ended hyperbranched polymers (NPHSH) and glycidyl methacrylate have been firstly reported. NPHSH is synthesized by an esterification between hydroxyl‐ended hyperbranched polymers (NPHOH) and 3‐mercaptopropionic acid. NPHOH is prepared by a thiol‐ene Michael addition between methacrylate group of a monomer and thiol group of linear monomer (AB) and/or branched monomer (AB₂). The molar ratio between the AB and AB₂ monomers controls the DB of the products. The ¹H NMR spectra analysis of NPHOH shows that their experimentally determined DBs are very close to their theoretical values, indicating good controllability of their DBs. The narrow molecular weight distributions of NPHOH, NPHSH, and NPEHP suggest high efficiency of the thiol‐ene Michael addition. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44277.     

Hyperbranched aliphatic polyester grafted attapulgite via a melt polycondensation process

A new process for the facile fabrication of the hyperbranched polymer grafted nano-surfaces was developed in the present work. The AB₂ type monomer, 2, 2-bis(hydroxymethyl)propionic acid (bis-MPA), was successfully grafted from the surfaces of the amino groups modified attapulgite nano-fibrillar clay (amino-ATP) via a melt polycondensation method with p-toluenesulfonic acid (p-TSA) as catalyst. Higher percentage of grafting (PG%) was achieved within shorter polymerizing time, compared with the product from the solution polycondensation method within longer polymerizing time. The surface composition and crystal structure of the hyperbranched aliphatic polyester grafted attapulgite (HAPE-ATP) were also characterized by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The transmission electron microscopy (TEM) analysis results showed that the dispersibility of the nano-fibrillar clay in organic solvent was improved after the graft polymerization.     

Branched poly(arylene ether ketone)s with tailored thermal properties: Effects of AB/AB2 ratio, core (B3) percentage, and reaction temperature

A series of poly(ether ketone) copolymers were prepared by nucleophilic aromatic polymerization reactions of the AB monomer 4-fluoro-4′-hydroxybenzophenone, 1, and the AB₂ monomer bis(4-fluorophenyl)-(4-hydroxyphenyl)phosphine oxide, 2, in the presence of 3 or 5 mol% of a highly reactive core molecule, tris(3,4,5-trifluorophenyl)phosphine oxide (B₃), 4. All of the copolymers prepared in the presence of a core molecule were sufficiently soluble in N-methylpyrrolidinone, NMP, to allow the determination of their molecular weights and polydispersity indices, PDIs. Number-average molecular weights, M_ns, of 3200-6800 Da were determined and the PDI values ranged from 1.41 to 4.07. The M_n was controlled by the mol% of 4 present in the reaction mixture with higher molar percentages leading to lower M_n values. Lower reaction temperatures and lower ratios of AB/AB₂ monomers afforded copolymers with lower PDI values. As expected, the crystallinity of the samples decreased with an increasing AB₂ content or an increase in PDI. The copolymers also exhibited excellent thermo-oxidative stability with a number of samples suffering 5% weight losses at temperatures, in air, well in excess of 450 °C.     

Synthesis and properties of new water-soluble aliphatic hyperbranched poly(amido acids) with high pH-dependent photoluminescence

Water-soluble fluorescent hyperbranched poly(amido acids) (HBPAAs), based on wholly aliphatic structures were prepared through direct self-condensation of N-(3-aminopropyl) diethano succinate amine (APDESA, AB₂ monomer) in the presence of N,N-dicyclohexylcarbodiimide (DCC) as a condensation agent. The resulting HBPAAs were soluble in water, DMF and THF, and the structure of synthesized AB₂ monomer and polymers was confirmed by IR, ¹H, and ¹³C NMR measurements. TEM image indicated that the HBPAAs self-assembled in H₂O to form a spherical micelle with a diameter ranging from 30 to 50 nm. A significant pH-dependent profile of fluorescent intensity in the pH range from 3 to 10 was observed, wherein pH 4 provided a critical jump as the solution pH was increased. Further increasing the pH to 10 decreased the fluorescence because of partial hydrolysis. Strong fluorescence emission was observed at 395 nm in aqueous media and the fluorescence quantum yields are to 23%. These amphiphilic HBPAAs, with excellent water-solubility, void-rich space, multiple functional peripheries and high blue fluorescence, have potential uses as tracing nanocarriers and molecular-level containers.     

Synthesis of a novel aromatic–aliphatic hyperbranched polyamide and its application in piezoelectric immunosensors

An aromatic–aliphatic AB₂ monomer, 5‐[3‐(4‐aminophenyl)propionylamino]isophthalic acid, prepared from 5‐aminoisophthalic acid and 3‐(4‐nitrophenyl)propionic acid, and the corresponding hyperbranched polyamide were fabricated. Applications in piezoelectric immunosensors as supports for antibody immobilization were studied. The introduction of the hyperbranched polyamide greatly increased the amount of immobilized antibody on the electrode and consequently increased the sensitivity of the complete piezoelectric immunosensor. The investigation of the properties of the sensors indicated that the hyperbranched polyamide was a suitable support for antibody/antigen immobilization. Copyright © 2007 Society of Chemical Industry     

Photopolymerization of hyperbranched aliphatic acrylated poly(amide ester). I. Synthesis and properties

The hyperbranched aliphatic poly(amide ester) (HAPAE) was synthesized based on 4‐N,N‐di(2‐hydroxy ethyl)‐4‐ketobutyric acid prepared by the reaction of succinic anhydride with diethanol amine, as an AB₂ monomer (repeating unit), and with 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol, as a core molecule, using acid catalysis. The second generation of the product was characterized by measuring dynamic viscosity, which decreased sharply with the increase in frequency. The product exhibits relative thermal stability as analyzed by thermogravimetry in a nitrogen atmosphere. The glass transition temperature, determined by differential scanning calorimetry, is ?27 °C. The molar mass was measured by vapor pressure osmometry. The polydispersity, measured by size exclusion chromatography, is 2.16. Dynamic mechanical thermal analyses were performed to characterize the thermal properties of the ultraviolet‐cured films of the acrylate‐modified HAPAE. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1630–1636, 2001     

Isothermal crystallization kinetics of AB<Subscript>3</Subscript> hyperbranched polymer (HBP)/polypropylene (PP) blends

In this paper, the isothermal crystallization kinetics of pure isotactic polypropylene (iPP) and iPP with 5% AB₃ hyperbranched polymer (HBP) added had been investigated by differential scanning calorimetry (DSC). During isothermal crystallization, the crystallization rate of the blends was higher than those of iPP remarkably. Moreover, the value of t _½ became smaller with increasing the HBP molecular weight in blends, however, the crystallization rate of the blend decreased when the higher molecular weight HBP (\( \bar{M}_{n} \) = 12,500) was added. The crystallization rate of the blends was more sensitive to temperature than that of iPP. An increase in the Avrami exponent may be attributed to the fractal structure of hyperbranched polymer.     

A novel hyperbranched polyester functionalized with azo chromophore: synthesis and photoresponsive properties

Summary A hyperbranched polymer containing azo chromophores on the periphery has been synthesized from transesterification reaction between a hyperbranched polyester bearing peripheral hydroxyl groups and ethyl 4-{4'-[N, Ndi(hydroxyethyl)aminobutoxy]phenylazo}benzoate. The hyperbranched polyester was obtained by adding the AB₂ monomers step by step to a multifunctional core molecule. Narrow molecular weight distribution, with a polydispersity index as low as 1.1, was achieved by this method. The azobenzene- functionalized hyperbranched polymer as well as the corresponding azo monomer showed typical photoresponsive behavior of an azobenzene type molecule. The trans azobenzene units of the hyperbranched polymer could be reversibly switched by UV irradiation to the cis form that recovered slowly to the trans form in the dark. However, significantly less conversion from the trans isomer to the cis isomer was observed for the azobenzenefunctionalized hyperbranched polymer at the photostationary states under the irradiation of UV light, which could be attributed to the increased steric hindrance in the hyperbranched polymer. Received: 1 April 2002 /Revised version: 10 July 2002/ Accepted: 15 July 2002     

Synthesis of hyperbranched aromatic polyamide–imide and its grafting onto multiwalled carbon nanotubes

A flexible hyperbranched aromatic polyamide–imide (PAI) having an amine group in the center and carboxyl groups in the ends was synthesized from a AB₂ type of monomer of 2‐(6‐aminohexylcarbomoyl) terephthalic acid that was prepared from trimellitic anhydride and 1,6‐diaminohexane. Fourier transformed infrared spectra (FTIR), NMR, and ES‐MS were used to characterize the structure of the monomer and the synthesized hyperbranched polymer. Then the hyperbranched PAI was grafted onto the multiwalled carbon nanotubes (MWNTs) that was first treated by acid and changed into MWNT‐COCl by SOCl₂ in a tetrahydrofuran solution. By observation with transmission electron microscopy and characterization with FTIR and thermal gravity of analysis, the functionalized MWNTs were terminally enclosed with polymer; it was believed that the MWNTs were linked with a big carboxylic claw at the end and the adsorption ability of the MWNTs to NH₂‐substrate was enhanced. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis, Characterization and Surface Properties of Series Sulfobetaine Surfactants

A series of surface active sulfo-propane betaines and sulfo-butane betaines were synthesized with high yields by the reaction of an appropriate N,N-dimethyl alkylamine with an excess of 1,3-propane sultone and 1,4-butane sultone. The structures were characterized by ¹H-NMR spectroscopy and elemental analysis. The micellar properties of these compounds were determined by surface tension methods. Surface tension measurements also provide information about the dependence of the surface tension at the CMC (??_cmc), pC₂₀ (negative logarithm of the surfactant molar concentration C₂₀ required to reduce the surface tension by 20 mN/m), the surface excess (??_max) at air/solution interface, the minimum area per surfactant molecule at the air solution interface (A).     

Study of negative substitution and monomer self‐condensation effects on molar mass and structural characteristics of hyperbranched polyesters originating from a high‐functionality core

In order to provide more insight into the effect of core functionality on hyperbranched polymer characteristics, two series of hyperbranched polyesters (HBPEs) were synthesized by reacting 2,2‐bis(methylol)propionic acid (bis‐MPA) as AB₂ monomer with both dipentaerythritol (DPE) and pentaerythritol as six (B₆)‐ and four (B₄)‐functional core molecules. The molar mass, composition and structure of HBPEs were determined with respect to the negative substitution logic and monomer self‐condensation effect. The molar masses and structures of HBPEs containing DPE core were less influenced by the negative effect of a reacted hydroxyl group on the reactivity of other hydroxyl groups in the same monomer unit. Thus, the use of DPE core in copolymerization with bis‐MPA monomer could help slightly to increase the molar mass of HBPEs. Conversely, the effect of self‐condensation of bis‐MPA on the molar mass reduction was more pronounced in the case of DPE hyperbranched polymers due to the A–B negative substitution effect. These two effects become more significant with increasing pseudo‐generation numbers of the HBPEs. © 2014 Society of Chemical Industry