Article
Polymer Science
Moritz Stuck, Irina Krenz, Benedikt Schulze Koekelsum, Susanne Boye, Brigitte Voit, Reinhard Lorenz
Summary: The study focused on the influence of different curing conditions and styrene concentrations on the resin properties, demonstrating that the Tg of the network can be increased by applying new thermal curing profiles and increasing the styrene content. Additionally, the partial substitution of problematic styrene with substances like maleic anhydride was found to significantly improve the reactivity and mechanical properties of the resin.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Polymer Science
Jiaxin Yu, Xiaojie Zhao, Yuhan Liu, Bao Zhang, Hongwei Pan, Huiliang Zhang, Baijun Liu, Yongfeng Men, Zhaoyan Sun, Wei Hu
Summary: A novel biodegradable polyester PB' ABT with high molecular weight and intrinsic viscosity was successfully synthesized in this study. The molecular structure and properties of the polyester can be effectively adjusted by controlling the monomer ratio. The experimental results demonstrated that PB' ABT showed excellent thermal stability, superior tensile properties, and biodegradability, indicating its potential wide application prospects.
POLYMER DEGRADATION AND STABILITY
(2023)
Article
Engineering, Chemical
Ana C. D. Pfluck, Dragana P. C. de Barros, Luis P. Fonseca
Summary: An innovative enzymatic polycondensation of dicarboxylic acids and dialcohols in aqueous polymerization media using free and immobilized lipases was developed. The best results for polycondensation were achieved using equimolar concentrations of octanedioic acid and 1,8-octanediol in a miniemulsion and water with immobilized Pseudozyma antarctica lipase B (PBLI). The benefits of polycondensation in aqueous media using an oil-in-water (o/w) miniemulsion or water include green process and green product, forming the basis of a greener polymer technology.
Article
Polymer Science
Mateus Hofmann, Mario Garrido, Marina Machado, Joao R. Correia, Joao C. Bordado
Summary: Research on biobased thermoset resins has been overlooked compared to biobased thermoplastics. This study developed low-molecular weight macromolecules with a high bio-content, suitable for various fiber-reinforced polymer production techniques. The resulting resins exhibited comparable mechanical and thermomechanical behavior to petrochemical-based counterparts, making them greener alternatives for high-performance structural applications.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Polymer Science
Takayoshi Katoh, Yukiko Ogawa, Yoshihiro Ohta, Tsutomu Yokozawa
Summary: The ester-ester exchange reaction proved to be faster than the ester-alcohol exchange reaction, leading to the successful synthesis of high-molecular-weight polyesters under various conditions. The copolymerization of different compounds through ester-ester exchange also resulted in the formation of new copolymers with confirmation from C-13 NMR spectroscopy and DSC thermal analysis.
JOURNAL OF POLYMER SCIENCE
(2021)
Article
Materials Science, Textiles
Kang Chen, Yanping Liu, Hong Ji, Yang Zhang, Minggen Song, Quan Jiang, Yumei Zhang, Huaping Wang
Summary: The study compared the performance and structures of PET fibers made with solid-state polycondensation (SSP) and liquid-state polycondensation (LSP) processes. It was found that the PET fiber with SSP had a larger molecular weight, greater tenacity, higher crystallinity and orientation compared to the fiber made with LSP.
JOURNAL OF THE TEXTILE INSTITUTE
(2021)
Article
Chemistry, Applied
Rushikesh S. Chanpurkar, Gajanan P. Lakhawat, Ruta D. Khonde
Summary: The lactide-based polyester resin synthesized in this study exhibited superior mechanical, rheological, and anticorrosive properties compared to simple polyester resins.
JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH
(2021)
Article
Polymer Science
Wangwang Duan, Xiaorui Li, Yiding Shen, Kai Yang, Hua Zhang
Summary: Solvent-free and highly branched water-soluble polyester (WPET) was prepared using self-emulsification methodology and used as a surface-sizing agent for cellulose fiber paper. WPET exhibited better surface sizing properties under specific conditions, showing clear relationships between its structure and the sized paper, as well as excellent mechanical properties and water resistance.
Article
Chemistry, Multidisciplinary
Takanori Kishida, Tomio Shimada, Kazunori Sugiyasu
Summary: We demonstrate that two epoxides can be efficiently linked using potassium thioacetate in water, even at imbalanced stoichiometric ratios. The first reaction between epoxide and thioacetate generates an intermediate that reacts with another epoxide with a much higher reactivity than thioacetate. This reaction enables nonstoichiometric polymerization of bifunctional epoxides and the formation of hydrogels and self-standing films in the presence of multifunctional epoxides.
CHEMICAL COMMUNICATIONS
(2022)
Article
Polymer Science
Takayoshi Katoh, Maai Saso, Yoshihiro Ohta, Tsutomu Yokozawa
Summary: We described a method of synthesizing polycarbonate through ester-carbonate exchange reaction, and achieving the exchange reaction between PC and other polymers under specific conditions. The composition of PC and PEs in the copolymer can be adjusted, and increasing polymerization degree leads to higher melting temperature of the copolymer.
Article
Chemistry, Multidisciplinary
Hideaki Ono, Shoko Ebisuya, Sayo Osanai, Shinji Tanaka, Masanori Tamura, Masaru Yoshida, Sho Inagak, Tomoki Dohi, Hidetomo Kai
Summary: A biodegradable poly((R)-3-hydroxybutyrate) was successfully synthesized by the acid-catalyzed dehydrative polycondensation of (R)-3-hydroxybutyric acid. Addition of a polymer-bound triphenyl-phosphine as a crotonoyl scavenger effectively prevented capping reactions by the crotonoyl group. The obtained telechelic polyester with carboxy and hydroxy groups at the two termini provides a new strategy for the copolymerization of poly(3-hydroxybutyrate).
Article
Polymer Science
Felix J. de Zwart, Petrus C. M. Laan, Nicole S. van Leeuwen, Eduard O. Bobylev, Erika R. Amstalden van Hove, Simon Mathew, Ning Yan, Jitte Flapper, Keimpe J. van den Berg, Joost N. H. Reek, Bas de Bruin
Summary: This study presents a new isocyanate-free method to produce polyureas by Ru-catalyzed carbene insertion into the N-H bonds of urea itself in combination with a series of bis-diazo compounds as carbene precursors. Kinetics and DFT studies revealed the rate-determining step to be nucleophilic attack on a Ru-carbene moiety by urea, paving the way for alternative routes to polyureas using transition-metal-catalyzed reactions.
Article
Chemistry, Analytical
G. Santhana Krishnan, S. Naveen, M. Shahnawaz, T. Ramcharan
Summary: In this study, the pyrolysis process of polydimethylsilane to polycarbosilane was investigated using evolved gas analysis and pyrolysis-gas chromatography-mass spectrometry. The results revealed the specific pyrolysis patterns and decomposition behavior of PDMS and PCS Mk-III.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2022)
Article
Energy & Fuels
Jun Li, Bin Lou, Luning Chai, Yue Fu, Ran Yu, Xin Gong, Dong Liu
Summary: This study investigates a two-stage thermotreatment process for optimizing the molecular structure and composition distribution of mesophase pitch, using boron trifluoride ethyl valerate complex as a catalyst. The results show that the two-stage thermotreatment process can alter the chemical structure of the aromatic nucleus and achieve a suitable softening point, as well as high content of organic structures and soluble sub-fractions.
Article
Polymer Science
Lifei Feng, Ran Li, Han Yang, Shanwei Chen, Wenbin Yang
Summary: A method of reinforcing and toughening unsaturated polyester resin (UPR) with a hyperbranched polyester (HBP-1) was reported. The results showed that HBP-1 enhanced the thermostability and mechanical properties of UPR.
Article
Biochemical Research Methods
Chuping Lee, Ellen D. Inutan, Jien Lian Chen, Mutanu M. Mukeku, Steffen M. Weidner, Sarah Trimpin, Chi-Kung Ni
Summary: The MAI matrix 3-NBN can produce intact, highly charged ions of nonvolatile compounds in high-vacuum TOF mass spectrometers with the aid of ablation and/or heating by laser irradiation, showing a different ionization mechanism from typical MALDI matrices. The morphology of 3-NBN:analyte crystals plays a significant role in ion generation in high vacuum.
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
(2021)
Article
Biochemical Research Methods
Zengchao Youa, Nithiya Nirmalananthan-Budaua, Ute Resch-Gengera, Ulrich Panne, Steffen M. Weidner
JOURNAL OF CHROMATOGRAPHY A
(2020)
Article
Polymer Science
Maria Baumann, Christian Wold, Elena Uliyanchenko, Steffen Weidner, Jana Falkenhagen
INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION
(2020)
Article
Polymer Science
Hans R. Kricheldorf, Steffen M. Weidner
Summary: The research showed that 2,2'-dihydroxybiphenyl is the most successful cocatalyst for bismuth subsalicylate in ring-opening polymerization of l-lactide, and optimization of reaction time and temperature is crucial for achieving high weight average molecular weights. Additionally, some unusual transesterification reactions were discovered, and triphenylphosphine was found to be an effective catalyst poison.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Polymer Science
Steffen M. Weidner, Hans R. Kricheldorf, Felix Scheliga
Summary: Copolymerizations of glycolide (GL) and l-lactide (LA) under different conditions lead to different conversion rates, and the temperature and catalyst significantly affect the structure and characteristics of the reaction products.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2021)
Article
Engineering, Environmental
Hans R. Kricheldorf, Steffen M. Weidner
Summary: Polymerizations of l-lactide were conducted with different catalysts and reaction conditions, resulting in the synthesis of poly(L-lactide) with varying molecular weights and chain structures. Neat SnCl2 showed the best performance in terms of obtaining high molecular weight linear chains.
JOURNAL OF POLYMERS AND THE ENVIRONMENT
(2021)
Article
Polymer Science
Hans R. Kricheldorf, Andreas Meyer, Steffen M. Weidner
Summary: The addition of difunctional cocatalysts can lead to the formation of high T-m crystallites in poly(l-lactide) during the polymerization process. Additionally, an unusual enthalpy-driven modification of the molecular weight distribution is observed in samples that have crystallized during polymerization.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Niklas Grabicki, Khoa T. D. Nguyen, Steffen Weidner, Oliver Dumele
Summary: A set of strained aromatic macrocycles based on [n]cyclo-2,7-(4,5,9,10-tetrahydro)pyrenylenes with size-dependent photophysical properties is presented. The rim confinement strategy makes cycloparaphenylenes an attractive supramolecular host family with strong binding capabilities. The structural and thermodynamic reasons for the exceptionally strong binding have been elucidated through combination of experimental and computational methods.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Polymer Science
Hans R. Kricheldorf, Felix Scheliga, Steffen M. Weidner
Summary: The definition of the term conversion in polymer synthesis is discussed, showing the need for multiple definitions in polymer science compared to organic and inorganic chemistry. The impact of increasing conversion on the structure and topology of homo- and copolymers is illustrated, along with consideration of various chain-growth polymerizations and chemical modifications of polymers.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Hans R. Kricheldorf, Steffen M. Weidner, Andreas Meyer
Summary: The alcohol-initiated ROPs of l-lactide at 160 degrees C for 72 hours produced high melting crystallites with melting temperatures of 189-193 degrees C, especially when using cyclic Sn(ii) compounds as catalysts. This suggests that the choice of catalyst can significantly impact the properties of the crystalline products.
Article
Polymer Science
Hans R. Kricheldorf, Steffen M. Weidner
Summary: The catalytic potentials of tin(II) acetate, tin(IV) acetate, dibutyltin-bis-acetate, and dioctyl tin-bis-acetate in polymerizations of L-lactide were compared, showing that SnAc2 had the highest reactivity. Different reaction conditions led to the formation of various polymer forms, with SnAc2 producing linear chains almost free of cyclics and SnAc4 yielding mixtures of cycles and linear species.
JOURNAL OF POLYMER SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Steffen M. Weidner, Andreas Meyer, Saber Chatti, Hans R. Kricheldorf
Summary: The study showed that annealing at different temperatures significantly influences the crystalline structure and molecular weight of cyclic polylactides, with high temperatures causing thermal degradation and partial conversion of cyclic chains into linear chains.
Article
Polymer Science
Hans R. Kricheldorf, Steffen M. Weidner, Felix Scheliga
Article
Polymer Science
Hans R. Kricheldorf, Steffen M. Weidner, Andreas Meyer
Article
Polymer Science
Hans R. Kricheldorf, Steffen M. Weidner
