Perfluoroalkyl‐terminated star polymer electrolyte

A perfluoroalkyl‐terminated multiarm star polymer (perfluoroalkyl‐terminated hyperbranched polyglycerol) was synthesized and characterized on the basis of perfluorooctanoyl chloride grafting on hyperbranched polyglycerol. The conductivity of a blend of the perfluoroalkyl‐terminated star polymer and linear poly(ether urethane) was studied. The results indicated that this blend had better solvating capability in salt and higher ionic conductivity. The conductivity of the blend was 2.5 × 10^?4 S cm^?1 at 60°C when the concentration of the perfluoroalkyl‐terminated hyperbranched polyglycerol was 30 wt % and the ethylene oxide (EO)/Li ratio was 4 in the blend. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 238–242, 2005     

Aliphatic polyamidoamine hyperbranched polymers/layered silicate nanocomposites

Polyamidoamine hyperbranched polymer (Hyp)/clay nanocomposites were synthesized by using both of montmorillonite and laponite clays. Poly amidoamine hyperbranched polymer (Hyp) was prepared by one‐pot polymerization via couple monomer methodology. Afterward, the amino ends of Hyp were modified with methyl methacrylate (MMA), styrene (St) and butyl methacrylate (n‐BuMA) polymers which were previously prepared via ATRP (atom transfer radical polymerization) to form the corresponding new hyperbranched polymers Hyp₁, Hyp₂ and Hyp₃. Those formed polymers were inserted into the modified clay, such as montmorillonite and laponite to form their nanocomposites. The formed polymer/clay nanocomposites were characterized via XRD, TEM, and thermal analyses. The formed hyperbranched polymers generally showed intercalation behavior more than the exfoliation one mostly because of the bulkiness of the hyperbranched skeleton. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Simultaneous polypropylene functionalization and nanoclay dispersion in PP/Clay nanocomposites using ultrasound

Polypropylene nanocomposite materials were prepared with 5 and 10 wt % cloisite C20A clay, jointly with 0.6 and 1.2 wt % of maleic anhydride (MA) for the simultaneous polymer functionalization and clay dispersion in a twin screw extruder assisted with ultrasonic irradiation, using different sonication intensities (231, 347, and 462 W, which correspond to 30%, 45%, and 60% of the maximum instrument intensity, “770 W”) all in a single‐step operation. The MA polymer functionalization was followed by FTIR spectroscopy and determined by titration. The increase in modulus of the obtained PP/Clay nanocomposites was attributed to the greater dispersion level, presumably achieved becuase of the joint application of the PP–Clay compatibilization with MA and the sonication during processing in a twin screw extruder. The greater level of clay dispersion was verified by the displacement of the XRD diffraction peak to lower angles, indicating an intercalated‐exfoliated structure that was corroborated by STEM. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40631.     

Tough hyperbranched epoxy/poly(amido‐amine) modified bentonite thermosetting nanocomposites

A tough and highly flexible hyperbranched epoxy and poly(amido‐amine) modified bentonite based thermosetting nanocomposite was demonstrated. The FTIR, XRD, and TGA analyses confirmed the modification of bentonite. The formation of partially exfoliated structure of the nanocomposite with good physicochemical interactions among the hyperbranched epoxy, poly(amido‐amine) hardener and modified clay was investigated by the FTIR, XRD, SEM, and TEM analyses. Significant improvements of 750% toughness, 300% elongation at break, 50% tensile strength, 300% modulus, and 250% adhesive strength of the pristine epoxy were achieved by the formation of nanocomposites with 3 wt % of modified clay. The experimental modulus values of the nanocomposites were compared with three theoretical models to account the interactions between filler and matrix. Thus, the studied epoxy nanocomposite has great potential to be used as an advanced epoxy thermoset. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40327.     

Melt processing and characterization of polypropylene/pristine montmorillonite nanocomposite: Influence of compatibilizer and hyperbranched polymer

In the present investigation, nanocomposites of polypropylene (PP)‐montmorillonite (MMT) clay were prepared by a single‐step compounding method to study the influence of hyperbranched polyester (HBPE) on rheological and mechanical properties of PP composites in the presence of a compatibilizer. In service of this objective, polyvinylchloride‐grafted‐maleic anhydride (PP‐g‐MA) was used as a compatibilizer for hydrophobic PP and hydrophilic clay. Rheological property in terms of melt viscosity was examined by a Brabender torque rheometer. The composite's morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), whereas the dispersion state of nanoparticles in the PP matrix was studied by X‐ray diffraction (XRD). The thermal behavior of nanocomposites was examined by differential scanning calorimetry (DSC). The analysis of results confirmed that the interactions among both additives significantly influenced the morphology, rheology, and thermomechanical properties of the nanocomposites. J. VINYL ADDIT. TECHNOL., 22:72–79, 2016. © 2014 Society of Plastics Engineers     

Correlating the rheological and mechanical response of polyurethane nanocomposites containing hyperbranched polymers

Cast polyurethane thermosets have been modified with randomly oriented exfoliated and intercalated montmorillonite clay using hyperbranched polymers (HBP) as reactive additives to promote dispersion of the clay platelets. The influence of the clay content on the stiffness of the nanocomposites is discussed in terms of simplified classical micromechanical models that allow correlations to be established between the properties of the final polyurethane and the limiting high strain rate shear viscosity of the HBP or HBP/polyethylene glycol nanocomposite precursors. Such models imply certain restrictions on the potential for mechanical reinforcement with unoriented platelets owing to crowding effects. Moreover, they appear unable to account simultaneously for the observed degrees of reinforcement in the glassy and the rubbery states, if currently accepted values for the stiffness of the MMT are assumed. Possible reasons for this are discussed.     

Hyperbranched–linear–hyperbranched ABA‐type block copolymers based on poly(ethylene oxide) and polyglycerol

BACKGROUND: Until recently, hyperbranched polymers were thought to be ill‐defined materials that were not useful as building blocks for well‐defined complex polymer architectures. It is a current challenge to develop strategies that offer rapid access to well‐defined hyperbranched block copolymers. RESULTS: A convenient three‐step protocol for the synthesis of double‐hydrophilic hyperbranched–linear–hyperbranched ABA‐type triblock copolymers based on poly(ethylene oxide) (PEO) and hyperbranched polyglycerol (hbPG) is presented. The Bola‐type polymers exhibiting an aliphatic polyether structure were prepared from a linear (lin) linPG‐b‐PEO‐b‐linPG precursor triblock. The materials exhibit low polydispersities (M_w/M_n) in the range 1.19–1.45. The molecular weights of the block copolymers range from 6300 to 26 200 g mol^?1, varying in the length of both the linear PEO chain as well as the hbPG segments. Detailed characterization of the thermal properties using differential scanning calorimetry demonstrates nanophase segregation of the blocks. CONCLUSION: The first example of well‐defined ABA hyperbranched–linear–hyperbranched triblock copolymers with PEO middle block and hbPG A‐blocks is presented. The biocompatible nature of the aliphatic polyether blocks renders these materials interesting for biomedical purposes. These new materials are also intriguing with respect to their supramolecular order and biomineralization properties. Copyright © 2009 Society of Chemical Industry     

Toughening of epoxy resin systems using low‐viscosity additives

This study has evaluated three low‐viscosity epoxy additives as potential tougheners for two epoxy resin systems. The systems used were a lower‐reactive resin based upon the diglycidyl ether of bisphenol A (DGEBA) and the amine hardener diethyltoluene diamine, while the second epoxy resin was based upon tetraglycidyl methylene dianiline (TGDDM) and a cycloaliphatic diamine hardener. The additives evaluated as potential tougheners were an epoxy‐terminated aliphatic polyester hyperbranched polymer, a carboxy‐terminated butadiene rubber and an aminopropyl‐terminated siloxane. This work has shown that epoxy‐terminated hyperbranched polyesters can be used effectively to toughen the lower cross‐linked epoxy resins, i.e. the DGEBA‐based systems, with the main advantage being that they have minimal effect upon processing parameters such as viscosity and the gel time, while improving the fracture properties by about 54 % at a level of 15 wt% of additive and little effect upon the T_g. This result was attributed to the phase‐separation process producing a multi‐phase particulate morphology able to initiate particle cavitation with little residual epoxy resin dissolved in the continuous epoxy matrix remaining after cure. The rubber additive was found to impart similar levels of toughness improvement but was achieved with a 10–20 °C decrease in the T_g and a 30 % increase in initial viscosity. The siloxane additive was found not to improve toughness at all for the DGEBA‐based resin system due to the poor dispersion within the epoxy matrix. The TGDDM‐based resin systems were found not to be toughened by any of the additives due to the lack of plastic deformation of the highly cross‐linked epoxy network Copyright © 2003 Society of Chemical Industry     

Hyperbranched‐modified epoxy thermosets: Enhancement of thermomechanical and shape‐memory performances

In this study a complete characterization of the thermomechanical and shape‐memory properties of epoxy shape‐memory polymers modified with hyperbranched polymer and aliphatic diamine was performed. Focusing on the mechanical properties that are highly desirable for shape‐memory polymers, tensile behavior until break was analyzed at different temperatures and microhardness and impact strength were determined at room temperature. As regards shape memory performance, the materials were fully characterized at different programming temperatures to study how this influenced the recovery ratio, fixity ratio, shape‐recovery velocity, and switching temperature. Tensile testing revealed a peak in deformability and in the stored energy density at the onset of the glass transition temperature, demonstrating that this is the best programming temperature for obtaining the best shape‐memory performances. The Young's moduli revealed more rigid structures in formulations with higher hyperbranched polymer content, while microhardness showed higher values with increasing hyperbranched polymer content due to the increased crosslinking density. Impact strength was greatly improved as the aliphatic diamine content increases due to the energy dissipation capability of its flexible structure. As regards the shape‐memory properties, increasing the programming temperature has a minor effect on formulations with a lower hyperbranched polymer content and worsens these properties when the hyperbranched polymer content is increased. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44623.     

Thermal degradation kinetics,mechanical, and flame retardant properties of epoxy‐HDPE fabric‐clay composite laminates

Addition of particulates into laminates has been found to influence thermal and mechanical properties. Composite laminates of epoxy‐high density polyethylene (HDPE) fabric‐clay were prepared by reinforcing clay in the range of 0.1–0.7 phr into epoxy‐HDPE fabric laminates. These laminates are characterized for their mechanical, thermal, and flame retardant performances. With the addition of clay, an increase was found in impact resistance, tensile strength, flexural strength, and Young's modulus to an extent of 0.2 phr clay, after which there is a decrease in these properties. The thermal stability is found to decrease with the addition of clay. The improved mechanical properties are obtained at the slight expense of thermal stability. UL‐94 tests indicate a reduction in the burning rate. Morphology of the broken samples indicate better dispersion at lower clay load and tactoid formation at higher clay loading. These materials have potential applications in agriculture, construction, and decorative purposes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40751.     

Synthesis of s‐triazine‐based hyperbranched polyurethane for novel carbon‐nanotube‐dispersed nanocomposites

s‐Triazine‐based hyperbranched polyurethanes (HBPUs) with different hard segments were synthesized by A₂ + B₃ approach. Various kinds of multiwalled carbon nanotube (MWNT) nanocomposites with HBPU were prepared to investigate an impact of hyperbranched polymer on dispersion of MWNTs in the polymer matrix and the resulting properties of nanocomposites. Synthesized HBPUs were characterized using FTIR and NMR measurements. The highly branched structures were found very effective in enhancing the pristine MWNT dispersion in the polymer matrix. As a result, the MWNT‐reinforced HBPU nanocomposites showed a steep increase in the yield stress and modulus and enhanced shape memory effect with an increase of hard segment and MWNT loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Complex aggregates formed with a hyperbranched polyglycerol derivative for drug delivery

An amphiphilic hyperbranched polyglycerol derivative (HPG‐C18) was synthesized by the anionic ring‐opening copolymerization with glycidol and 1,2‐epoxyloctadecane as the monomers. This hyperbranched polymer formed large complex aggregates as confirmed by dynamic light scattering and transmission electron microscopy tests. Because of its amphiphilic properties, HPG‐C18 was explored to load hydrophobic docetaxel, a clinical antitumor drug, and deliver it into breast cancer cell line (MCF‐7) cells. To investigate the application of the aggregates in drug delivery, blood compatibility was studied by hemolysis analysis, red blood cell observation, and thromboelastography assay. These results indicate that HPG‐C18 inhibited MCF‐7 proliferation effectively with good blood compatibility, and this suggested a potential application in tumor therapy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42895.     

Developing a Novel Hyperbranched Polymer-Modified PP/Clay Nanocomposite: Characteristics Investigation

Polypropylene, as a thermoplastic polyolefin, possesses advantageous physical, mechanical and thermal characteristics, but also suffers from disapproving lesser properties such as poor dye- and coat-ability. Herein, nanoclay particles and a polyester-amide-based hyperbranched polymer are utilized to improve paint-ability along with mechanical properties. XRD and SEM results rationalize the idea that maleic anhydride-modified polypropylene and hyperbranched polymer together improve the nanoclay dispersion. The corresponding idea of “molecular skateboards” is also developed via rheology measurements. DMA data demonstrate that mechanical characteristics of the hyperbranched polymer-modified samples remain intact or even improved comparing neat polypropylene and contact angle measurements reveal reduction in θ values.      

Lignin valorization by forming thermally stimulated shape memory copolymeric elastomers—Partially crystalline hyperbranched polymer as crosslinks

Lignin based thermal‐responsive elastomers were produced by a melt polycondensation reaction with a long alkyl chain hyperbranched poly(ester‐amine‐amide) (B₃‐A₂‐CB₃¹). The effect of lignin content on elastomers properties was investigated. The thermal and mechanical properties of the copolymers were characterized by DMA, DSC, and TGA. The morphology of the copolymer was examined by SEM. Tensile properties were dominated by HBP <25% lignin content while lignin dominated >25% content. The copolymers glass transition temperature (T_g) increased with lignin content. The elastomer with 30% lignin content demonstrated optimal mechanical properties (tensile strength 5.3 MPa, Young's modulus 8.9 MPa, strain at break 301%, and toughness 1.03 GPa). Thermally stimulated dual shape memory effects (SME) of the copolymers were quantified by cyclic thermomechanical tests. The transition temperature (T_trans) of the polymer was able to be controlled (room to body temperature) by varying the amount of lignin added which broadens the range to medical applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41103.     

Synthesis and characterization of nanoclay–polymer composites from soil clay with respect to their water‐holding capacities and nutrient‐release behavior

Water and nutrients are two important inputs to agriculture that need to be used judiciously with higher efficiency to save these limited resources. For these purposes, a series of nanoclay–polymer composite (NCPC) superabsorbent nutrient carriers were prepared. These NCPCs were based on the reactions of different types of nanoclays (10 wt %) with partially neutralized acrylic acid and acryl amide by a free‐radical aqueous solution copolymerization reaction with N,N′‐methylene bisacrylamide as a crosslinker and ammonium persulfate as an initiator. The nanoclays isolated from three different types of soils were dominant in kaolinite (clay I ), mica (clay II ), and montmorillonite (clay III ), and a portion of each was freed from amorphous aluminosilicate. Thus, there were six different types of nanoclays used, namely, those dominated by kaolinite, mica, and smectite with and without amorphous aluminosilicate. Fourier transform infrared spectroscopy and X‐ray diffraction (XRD) investigations showed evidence of interaction between the clays and polymer. XRD investigation also showed that the reaction between the polymer and clays I and II occurred on the surface of various clay particles without intercalating into the stacked silicate galleries, whereas in the case of clay III (the smectite‐dominated clay), evidence indicated the intercalation of polymer into the stacked silicate galleries of the clay and the exfoliation of the clay. The water absorbency decreased in the NCPCs compared to that of the pure polymeric hydrogel. In case of the pure polymer, the entire amount of nutrient loading released within 15 h of incubation; this was higher than that of the NCPCs. In the initial stage (up to 15 h), no significant differences in nutrient release were observed among the different polymer/clay composites, but there were differences in later stages. Among the different NCPCs, the percentage release of nutrients at 48 h ranged from around 70% in the polymer/clay III composite to 90% in the polymer/clay I composite. The presence of amorphous aluminosilicates in clay did not make any difference in the nutrient‐release rate. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39951.     

Mechanical and thermal properties of modified kaolin clay/unsaturated polyester nanocomposites

The improvement in thermal and mechanical properties of Nanocomposites prepared with unsaturated polyester (UP) as polymer matrix and various loadings of amino‐modified nano kaolinite clay as filler has been studied. Mechanical stirring and ultrasonication resulted in better dispersion of the clay. For curing polyester resin, cobalt naphthenate was used as accelerator and MEKP as initiator. Dynamic Mechanical Analysis (DMA) was carried out to find storage and loss modulus. Thermal stability was found through thermogravimetric analysis and the evaluation of structure and morphology of the nanocomposites were done through XRD, SEM, and TEM. Nanocomposite with 3 phr of amino modified clay has shown higher storage modulus and an improved thermal stability of UP/clay nanocomposites has been established. Tensile strength and toughness of the composite have been found to achieve maximum values at 1 phr of clay and the storage modulus has had an improvement of 38% compared to neat UPR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43245.     

Synthesis of Fluorinated Hyperbranched Polymers and Their Use as Additives in Cationic Photopolymerization

Summary: A fluorine containing hyperbranched polymer was synthesized by modifying an aromatic‐aliphatic hyperbranched polyester with a semifluorinated alcohol via a Mitsunobu reaction and was subsequently used as an additive in cationic photopolymerization of an epoxy resin. The remaining OH groups of the fluorinated hyperbranched polymer interact with the polymeric carbocation through a chain‐transfer mechanism inducing an increase in the final epoxy conversion. The fluorinated HBP induces modification of bulk and surface properties, with an increase in T_g and surface hydrophobicity already reached at very low concentration. The HBFP additive can, therefore, protect the coatings from aggressive solvents, increases hardness, and allows the preparation of a low energy surface coating.

Synthesis of fluorinated hyperbranched polyester.     

Thermal,mechanical, and barrier properties of polyethylene/surlyn/organoclay nanocomposites blown films prepared by different mixing methods

(Low‐density polyethylene) (LDPE)/clay nanocomposites were prepared by melt blending in a twin‐screw extruder by using different mixing methods. Zinc‐neutralized carboxylate ionomer was used as a compatibilizer. Blown films of the nanocomposites were then prepared. The effect of mixing method on the clay dispersion and properties of the nanocomposites was evaluated by wide‐angle X‐ray diffraction analysis, mechanical properties, thermal properties, and barrier properties. The structure and properties of nanocomposites containing different amounts of nanoclay prepared by selected mixing techniques were also investigated. It was found that melt compounding of Surlyn/clay masterbatch with pure LDPE and Surlyn (two‐step‐a method) results in better dispersion and intercalation of the nanofillers than melt mixing of LDPE/Surlyn/clay masterbatch with pure LDPE and surlyn (two‐step‐b method) and direct mixing of LDPE with clay. The films containing ionomer have good barrier properties. A wide‐angle X‐ray diffraction pattern indicates that intercalation of polymer chains into the clay galleries decreases by increasing the clay content. Barrier properties and tensile modulus of the films were improved by increasing the clay content. In addition, tensile strength increased in the machine direction, but it decreased in the transverse direction by increasing the clay content. DSC results showed that increasing the clay content does not show significant change in the melting and crystallization temperatures. The results of thermogravimetric analysis showed that the thermal stability of the nanocomposites decreased by increasing the clay content more than 1 wt%. J. VINYL ADDIT. TECHNOL., 21:60–69, 2015. © 2014 Society of Plastics Engineers     

Cationic and hydrophobically modified chitosans as additives for water‐based drilling fluids

Water‐soluble chitosan derivatives are synthesized via a two‐step procedure that includes the hydrophobization of chitosan using different acyl chlorides, and then the alkylation of some of the amine groups. Rheology, conventional rolling, and filtration tests are performed to evaluate the effect of the modified polysaccharides on the rheological behavior of the fluid, as well as on the clays cuttings integrity and on the control of fluid loss for the geological formations. The results indicate that the product with C16 segments, 2% (wt/vol) concentration and high molar weight led to aqueous solutions with a pseudoplastic behavior equivalent to the one presented by the commercial rheology modifier used in water‐based drilling fluids. In addition, the hydrophobically modified cationic chitosan shows an excellent capacity for inhibiting the clays reactivity and for keeping the cuttings integrity. The results also show that this product can significantly decrease the volume of filtrate, leading to values comparable to the ones obtained with commercial additives, and therefore suggesting that it could be considered to replace some of the drilling fluid additives commonly used. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40300.     

Mechanical properties of layered silicate/starch polycaprolactone blend nanocomposites

The mechanical behavior of layered silicate/starch polycaprolactone blend nanocomposites was evaluated. Three different clays (Cloisite Na⁺, Cloisite 30B and Cloisite 10A) were used as reinforcement. Nanocomposites were prepared by melt intercalation followed by compression molding. These nanocomposites were characterized using X‐ray diffraction, scanning electron microscopy, dynamic mechanical analysis and tensile testing. X‐ray diffraction results showed that most of the clays were intercalated within the polymeric chains. In all cases, mechanical properties were improved with clay incorporation and the improvement was better as the clay content was increased. The best properties were achieved with Cloisite 10A due to their greatest compatibility with the matrix. A mechanical model, which takes into account the effective parameters of the clay, was used in order to estimate the dispersion of clay within the polymer. The highest dispersion was obtained for Cloisite 10A, which is in accordance with the experimental mechanical properties. Although dynamical‐mechanical properties improved with clay incorporation, the glass transition temperature was not affected. Copyright © 2006 Society of Chemical Industry