The Experts below are selected from a list of 4203 Experts worldwide ranked by ideXlab platform
Chuanbing Tang - One of the best experts on this subject based on the ideXlab platform.
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Designing Block Copolymer Architectures toward Tough Bioplastics from Natural Rosin
2017Co-Authors: Md Anisur Rahman, Hasala N. Lokupitiya, Mitra S. Ganewatta, Liang Yuan, Morgan Stefik, Chuanbing TangAbstract:Resin acids (or natural Rosin) are a class of abundant, renewable natural biomass. Most low molecular weight resin acid-containing polymers are very brittle due to their low chain entanglement associated with the pendant, intrinsically bulky hydrophenanthrene group. The use of block copolymer architectures can enhance chain entanglement and thus improve toughness. A–B–A type triblock and A–B–A–B–A type pentablock copolymers were synthesized by ring-opening metathesis polymerization (ROMP) with one-pot sequential monomer addition of a Rosin-based monomer and norbornene. We investigated the effect of chain architecture and microphase separation on mechanical properties of both types of block copolymers. Pentablock copolymers exhibited higher strength and toughness as compared to both the triblock copolymers and the corresponding homopolymers. The greater toughness of pentablock copolymers is due to the presence of the Rosin-based midblock chains that act as bridging chains between two polynorbornene domains. SAXS and AFM data were consistent with short-range phase separation of microdomains in all tri- and pentablock copolymers
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amphipathic antibacterial agents using cationic methacrylic polymers with natural Rosin as pendant group
2012Co-Authors: Ying Chen, Perry A Wilbon, Yung Pin Chen, Juhua Zhou, Alan W Decho, Chunpeng Wang, Mitzi Nagarkatti, Chuanbing TangAbstract:We prepared a class of novel cationic polymers as antimicrobial agents: quaternary ammonium-containing poly(N,N-dimethylaminoethyl methacrylate) with natural Rosin as the pendant group (PDMAEMA-g-Rosin). Different from most other amphipathic antimicrobial polymeric systems reported in the literature, our approach sandwiched the hydrophilic cationic group between the polymer backbone and bulky hydrophobic hydrophenanthrene side groups. A simple quaternization reaction was used to link the Rosin ester chloride and PDMAEMA homopolymers. Both the Gram-positive bacterium Staphylococcus aureus (S. aureus) and Gram-negative bacterium Escherichia coli (E. coli) were tested against the PDMAEMA-g-Rosin copolymers. PDMAEMA-g-Rosin copolymers with the amphipathic structure exhibited effective antimicrobial activity against both E. coli and S. aureus. Both the degree of quaternization of Rosin group and the molecular weight of PDMAEMA played roles in antimicrobial activities. Our results also indicated that conformation of hydrophobic group (particularly steric hindrance) played a role in dictating antibacterial efficacy. Scanning electron microscopy and confocal laser scanning microscopy were used to characterize morphological changes of bacteria after exposure with PDMAEMA-g-Rosin copolymers. Possible mechanisms on a combination of ionic and hydrophobic interactions between bacterial cells and polymers are discussed.
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combining renewable gum Rosin and lignin towards hydrophobic polymer composites by controlled polymerization
2011Co-Authors: Jifu Wang, Chunpeng Wang, Kejian Yao, Andrew L Korich, Harry J Ploehn, Peter M Iovine, Fuxiang Chu, Chuanbing TangAbstract:Rosin polymer-grafted lignin composites were pre- pared via ''grafting from'' atom transfer radical polymerization (ATRP) with the aid of 2-bromoisobutyryl ester-modified lignin as macroinitiators. Three different monomers derived from dehydroabietic acid (DA) were used for execution of grafting from ATRP, while DA was separately attached onto lignin by a simple esterification reaction. Kinetic studies indicated con- trolled and ''living'' characteristics of all monomer polymeriza- tions. Thermal studies indicated that Rosin polymer-grafted lignin composites exhibited glass transition temperatures in a broad temperature range from � 20 to 100 � C. The grafting of both DA and Rosin polymers significantly enhanced hydropho- bicity of lignin. Static contact angle measurement of water droplets showed � 90 � for all these Rosin modified lignin com- posites. X-ray photoelectron spectroscopy demonstrated that the surface of Rosin-lignin composites was dominated with chemical compositions originating from the hydrocarbon rich Rosin moiety. The impartation of hydrophobicity of Rosin into lignin provided excellent water resistance of this class of renewable polymers, as all Rosin-modified lignin com- posites showed water uptake below 1.0 wt %. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3728-3738, 2011
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degradable Rosin ester caprolactone graft copolymers
2011Co-Authors: Kejian Yao, Chunpeng Wang, Jifu Wang, Fuxiang Chu, Wujie Zhang, James Lee, Chuanbing TangAbstract:We have carried out the synthesis of side-chain Rosin-ester-structured poly(e-caprolactone) (PCL) through a combination of ring-opening polymerization and click chemistry. Rosin structures are shown to be effectively incorporated into each repeat unit of caprolactone. This simple and versatile methodology does not require sophisticated purification of raw renewable biomass from nature. The Rosin properties have been successfully imparted to the PCL polymers. The bulky hydrophenanthrene group of Rosin increases the glass-transition temperature of PCL by >100 °C, whereas the hydrocarbon nature of Rosin structures provides PCL excellent hydrophobicity with contact angle very similar to polystyrene and very low water uptake. The Rosin-containing PCL graft copolymers exhibit full degradability and good biocompatibility. This study illustrates a general strategy to prepare a new class of renewable hydrocarbon-rich degradable biopolymers.
Roberto Lazzaroni - One of the best experts on this subject based on the ideXlab platform.
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microscopic morphology of blends between a new all acrylate radial block copolymer and a Rosin ester resin for pressure sensitive adhesives
2008Co-Authors: Melanie Jeusette, Sophie Peeterbroeck, F Simal, D Cossement, Patrice Roose, Ph Leclere, Ph Dubois, M Hecq, Roberto LazzaroniAbstract:Abstract With the goal of developing new pressure sensitive adhesive systems, the miscibility and the phase morphology of blends between novel symmetric four-arm star “all-acrylate” block copolymers synthesized by atom transfer radical polymerization (ATRP) and a Rosin ester resin tackifier was studied with a combined differential scanning calorimetry (DSC) and atomic force microscopy (AFM) approach. Copolymer–resin compositions with increasing resin content in the blend were studied. The DSC results show good miscibility for compositions lower than 60 wt%, with a single glass transition at a temperature between those of the two pure compounds. The AFM results indicate that the initial two-phase morphology typical of the block copolymer matrix is preserved up to 60 wt% of resin. Above that value, a third phase, attributed to aggregates of the pure resin, is observed. Upon ageing, the homogeneous systems (e.g., blends with 40 wt% of resin) undergo a slow migration of the tackifying resin towards the surface of the sample, which can be understood in terms of surface free energy considerations. This eventually leads to the formation of a layer of pure resin at the surface.
Jose Miguel Martinmartinez - One of the best experts on this subject based on the ideXlab platform.
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new binary blends of ethylene co n butyl acrylate eba copolymer and low molecular weight Rosin ester resin with potential as pressure sensitive adhesives
2018Co-Authors: Sara Sanchoquerol, Andres Jesus Yanezpacios, Jose Miguel MartinmartinezAbstract:For improving the adhesion property of ethylene-co-n-butyl acrylate copolymer (EBA) at ambient temperature, binary blends of EBA with 27 wt% n-butyl acrylate and different amounts (20–62 wt%) of low molecular weight hydrogenated glycerol Rosin ester (ECH) resin have been prepared. The addition of glycerol Rosin ester resin decreased the crystallinity and size of the ethylene domains of the EBA copolymer. The addition of up to 50 wt% (100 phr) ECH resin improved the compatibility with the EBA copolymer, whereas when more than 50 wt% (100 phr) ECH resin was added, the compatibility of the blends did not change but the viscoelastic properties were noticeably decreased. Furthermore, the compatibility was noticeably improved by adding only 20 wt% ECH resin although the best compromise between compatibility and viscoelasticity corresponded to the binary blend made with 43 wt% ECH resin. The EBA copolymer + ECH resin blends showed high tack (initial adhesion) at 25 °C and some of them even at 5 °C, and they have adequate 180° peel strength both to polar (polyethylene terephthalate-PET) and nonpolar (polypropylene-PP) substrate. Furthermore, all EBA copolymer + ECH resin blends showed high shear strength at 25 °C. Finally, the blend with 43 wt% ECH resin showed excellent pressure sensitive adhesive property exhibiting excellent creep, high tack, high 180° peel strength, and high single lap-shear strength.
Fuxiang Chu - One of the best experts on this subject based on the ideXlab platform.
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preparation and characterization of natural Rosin stabilized nanoparticles via miniemulsion polymerization and their pressure sensitive adhesive applications
2018Co-Authors: Jifu Wang, Chunpeng Wang, Yupeng Liu, Fuxiang ChuAbstract:Abstract A series of Rosin stabilized nanoparticles were prepared by miniemulsion polymerization. The hydrophobicity of dehydroabietic acid (DA) from Rosin or from DA derived acrylic monomer (AEDA) was employed to stabilize the monomer miniemulsions. Then miniemulsion polymerizations of these monomer miniemulsions were performed separately and achieved the Rosin stabilized nanoparticles with a near-monodisperse spherical morphology, respectively. This approach can effectively incorporate DA or AEDA into polyacrylate miniemulsion. Herein, AEDA played a role as both costabilizer and reactant in miniemulsion polymerization, and high molecular weight AEDA-MMA copolymers were achieved. The introduction of Rosin’s moiety also could afford its copolymers with an improved thermal stability and mechanical property. Unlike conventional usage of Rosin derivatives as a tackifying resin in pressure-sensitive adhesives (PSA), AEDA served as a hard component and improved the holding power of PSA, which opens a new platform for the using of Rosin.
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combining renewable gum Rosin and lignin towards hydrophobic polymer composites by controlled polymerization
2011Co-Authors: Jifu Wang, Chunpeng Wang, Kejian Yao, Andrew L Korich, Harry J Ploehn, Peter M Iovine, Fuxiang Chu, Chuanbing TangAbstract:Rosin polymer-grafted lignin composites were pre- pared via ''grafting from'' atom transfer radical polymerization (ATRP) with the aid of 2-bromoisobutyryl ester-modified lignin as macroinitiators. Three different monomers derived from dehydroabietic acid (DA) were used for execution of grafting from ATRP, while DA was separately attached onto lignin by a simple esterification reaction. Kinetic studies indicated con- trolled and ''living'' characteristics of all monomer polymeriza- tions. Thermal studies indicated that Rosin polymer-grafted lignin composites exhibited glass transition temperatures in a broad temperature range from � 20 to 100 � C. The grafting of both DA and Rosin polymers significantly enhanced hydropho- bicity of lignin. Static contact angle measurement of water droplets showed � 90 � for all these Rosin modified lignin com- posites. X-ray photoelectron spectroscopy demonstrated that the surface of Rosin-lignin composites was dominated with chemical compositions originating from the hydrocarbon rich Rosin moiety. The impartation of hydrophobicity of Rosin into lignin provided excellent water resistance of this class of renewable polymers, as all Rosin-modified lignin com- posites showed water uptake below 1.0 wt %. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3728-3738, 2011
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degradable Rosin ester caprolactone graft copolymers
2011Co-Authors: Kejian Yao, Chunpeng Wang, Jifu Wang, Fuxiang Chu, Wujie Zhang, James Lee, Chuanbing TangAbstract:We have carried out the synthesis of side-chain Rosin-ester-structured poly(e-caprolactone) (PCL) through a combination of ring-opening polymerization and click chemistry. Rosin structures are shown to be effectively incorporated into each repeat unit of caprolactone. This simple and versatile methodology does not require sophisticated purification of raw renewable biomass from nature. The Rosin properties have been successfully imparted to the PCL polymers. The bulky hydrophenanthrene group of Rosin increases the glass-transition temperature of PCL by >100 °C, whereas the hydrocarbon nature of Rosin structures provides PCL excellent hydrophobicity with contact angle very similar to polystyrene and very low water uptake. The Rosin-containing PCL graft copolymers exhibit full degradability and good biocompatibility. This study illustrates a general strategy to prepare a new class of renewable hydrocarbon-rich degradable biopolymers.
Melanie Jeusette - One of the best experts on this subject based on the ideXlab platform.
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microscopic morphology of blends between a new all acrylate radial block copolymer and a Rosin ester resin for pressure sensitive adhesives
2008Co-Authors: Melanie Jeusette, Sophie Peeterbroeck, F Simal, D Cossement, Patrice Roose, Ph Leclere, Ph Dubois, M Hecq, Roberto LazzaroniAbstract:Abstract With the goal of developing new pressure sensitive adhesive systems, the miscibility and the phase morphology of blends between novel symmetric four-arm star “all-acrylate” block copolymers synthesized by atom transfer radical polymerization (ATRP) and a Rosin ester resin tackifier was studied with a combined differential scanning calorimetry (DSC) and atomic force microscopy (AFM) approach. Copolymer–resin compositions with increasing resin content in the blend were studied. The DSC results show good miscibility for compositions lower than 60 wt%, with a single glass transition at a temperature between those of the two pure compounds. The AFM results indicate that the initial two-phase morphology typical of the block copolymer matrix is preserved up to 60 wt% of resin. Above that value, a third phase, attributed to aggregates of the pure resin, is observed. Upon ageing, the homogeneous systems (e.g., blends with 40 wt% of resin) undergo a slow migration of the tackifying resin towards the surface of the sample, which can be understood in terms of surface free energy considerations. This eventually leads to the formation of a layer of pure resin at the surface.
