Article
Chemistry, Analytical
Young-Su Jeong, Jaegi Lee, Gwang-Min Sun, Bo-Young Han, Young-Rang Uhm, Yongmin Kim
Summary: This study investigated the effect of polymer adhesive on positron annihilation lifetime spectroscopy and found that the unnecessary components caused by the adhesive can be eliminated through source correction. It is recommended to minimize the amount of polymer adhesive in the positron source for accurate analysis of positron lifetimes.
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
(2023)
Article
Materials Science, Characterization & Testing
M. Gruendken, D. Koda, J. Dryzek, A. Blume
Summary: Liquid polymers are used as plasticizers in elastomeric compounds to modify their processing and final characteristics. The study discusses the plasticizing effects and contributions to crosslinking in sulfur cured SSBR mixtures with the incorporation of different types of liquid polymers. The free volume measured by positron annihilation lifetime spectroscopy either increases or decreases depending on the amount of liquid polymer incorporated in the main polymer.
Article
Biochemistry & Molecular Biology
Giovanni Consolati, Eros Mossini, Dario Nichetti, Fiorenza Quasso, Giuseppe Maria Viola, Erkin Yaynik
Summary: The study compared the free volume fraction obtained from experiments with the lattice-hole model, revealing that a cylindrical flattened geometry of the cavities provided better agreement than a spherical shape. Additionally, the best fit was found for holes that expanded preferentially in the radial direction, with a decrease in aspect ratio as temperature decreased.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Polymer Science
Hang Guo, Zhilong Hong, Dongmei Huang, Erjie Yang, Zhuangzhuang Zhu, Chenhao Zhao, Yun Dong, Bangjiao Ye, Hongjun Zhang, Liangbin Li
Summary: The structure-property relationship of the interlamellar amorphous phase in semicrystalline polymers has been a fundamental yet controversial topic in polymer physics. This study simplifies the mechanical coupling between the two phases and quantitatively characterizes the evolution of the amorphous structure and its connection to the mechanical behavior using advanced techniques.
Article
Engineering, Environmental
David Pavel Kralovic, Katarina Cifranicova, Helena Svajdlenkova, Darina Tothova, Ondrej Sausa, Pavol Kalinay, Taras Kavetskyy, Jolita Ostrauskaite, Oleh Smutok, Mykhailo Gonchar, Vladimir Soloviev, Arnold Kiv
Summary: This study investigated the influence of aromatic rings on the local free volume of cured mixtures of acrylate epoxidized soybean oil (AESO) and vanillin dimethacrylate (VDM). The results showed that increasing the content of VDM caused a decrease in the local free volume of the cured polymer network, affecting the diffusion properties of the polymer and reducing the conversion of double bonds.
JOURNAL OF POLYMERS AND THE ENVIRONMENT
(2023)
Article
Polymer Science
Shinian Cheng, Zaneta Wojnarowska, Malgorzata Musial, Slawomir Kolodziej, Eric Drockenmuller, Marian Paluch
Summary: The study investigates the volume effects in a specific 1,2,3-triazolium-based poly(ionic liquid) at both the macro and nano scales. The experimental determination of a relatively large free volume (V-f) suggests it as the main factor controlling the superionic properties of the material. The analysis of specific volume and relaxation dynamics in terms of different models did not work for the studied system.
Article
Polymer Science
Katarina Cifranicova, Ondrej Sausa, David Pavel Kralovic, Helena Svajdlenkova
Summary: This study investigated a commercial photopolymer mixture using positron annihilation spectroscopy (PALS), near infrared spectroscopy (NIR), and bulk density measurements to study microstructural free volume, which affects material properties. It was found that 0.5 mol% of photoinitiator (PI) is sufficient to achieve similar microstructures for 2 mm and 5 mm-thick samples. The thickness and amount of PI were found to have an impact on the free volume characteristics, which correlated with bulk density, monomer conversion, and H bonded interactions determined from NIR. Spatial graded microstructural study revealed more pronounced differences with increased PI amount and reduced thickness.
Article
Chemistry, Multidisciplinary
Yuma Goto, Shun Omagari, Ryuma Sato, Takuya Yamakado, Ryo Achiwa, Nilanjan Dey, Kensuke Suga, Martin Vacha, Shohei Saito
Summary: The study utilized a dual fluorescent molecular probe to monitor nanoscale dynamics in polystyrenes, revealing that planarization of the molecule in the excited state only occurs when a large polymer free volume is available nearby, lasting on average 1.2 seconds. This investigation provides insights into the dynamics of molecular environments through statistical analysis and computational simulations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Sebastian M. Fica-Contreras, David J. Hoffman, Junkun Pan, Chungwen Liang, Michael D. Fayer
Summary: The study investigates the size, distribution, dynamics, and electrostatic properties of free volume elements (FVEs) in two polymers using the ROAM technique. It found that PS has larger FVEs and a broader distribution compared to PMMA, with FVE structural dynamics occurring on a 150 ps time scale in both polymers. Additionally, the FVE radius probability distribution in PS is non-Gaussian with a tail to larger radii, while the distribution in PMMA is closer to Gaussian.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Review
Polymer Science
Giovanni Consolati, Dario Nichetti, Fiorenza Quasso
Summary: Positron annihilation lifetime spectroscopy (PALS) is a valuable technique used to investigate defects in solids with a sensitivity of 10(-7). It can reveal the size, structure, and concentration of vacancies in metals, alloys, semiconductors, porous systems, and polymers. PALS provides quantitative measurements of the free volume, which is correlated to important properties of polymers and can be deduced theoretically.
Article
Chemistry, Multidisciplinary
Lei Yang, Xuyang Liu, Zhouxun Lu, Tong Song, Zhihong Yang, Jianmei Xu, Wei Zhou, Xingzhong Cao, Runsheng Yu, Qing Wang
Summary: The study investigates the influence of free volume on the dielectric properties of PVDF/Al2O3 composites. It reveals that the greatly enlarged size of free volume holes can result in remarkable frequency dependence of the dielectric constant in such composites, providing valuable insights for the research and optimization of dipolar dielectric polymer composites.
Article
Chemistry, Applied
Santiago Estevez-Areco, Carlos Macchi, Lucas Guz, Silvia Goyanes, Alberto Somoza
Summary: The effect of citric acid (CA) concentration and water content on the free hole volume of thermoplastic cassava starch films (TPS) was studied. The increase in CA concentration leads to wider free hole volume distributions with lower mean values. The water vapour permeability was significantly higher in films incorporating 5 % (w/w) of CA, in line with the more open network of this material that was revealed in the hole volumes distribution.
CARBOHYDRATE POLYMERS
(2023)
Article
Polymer Science
Fang Wei, Junheng Zhang, Cheng Wu, Mi Luo, Bangjiao Ye, Hongjun Zhang, Junsheng Wang, Menghe Miao, Tingcheng Li, Daohong Zhang
Summary: Recyclable flame-retardant epoxy resins (FREPs) have been developed using itaconic acid-derived hyperbranched epoxy resin (IA-EHBP) and (1,3,5-hexahydro-s-triazine-1,3,5-triyl)benzyl mercaptan (HT-BM). These resins can be degraded into monomers with high yield and the IA-EHBP structure improves their mechanical properties. The incorporation of IA-EHBP also enhances the flame retardancy of the resins by promoting char residue formation and preventing the generation of combustible volatiles. This method provides a convenient and closed-loop approach for efficient chemical recycling and reuse of end-of-life flame-retardant materials.
Article
Chemistry, Physical
F. J. Ye, T. Zhu, Q. Q. Wang, Y. M. Song, H. Q. Zhang, P. Zhang, P. Kuang, R. S. Yu, X. Z. Cao, B. Y. Wang
Summary: The effects of thermal annealing on vacancy-type defects and Cr segregation in deformed CoCrFeMnNi alloys were investigated. It was found that severe plastic deformation led to Cr segregation at grain boundaries, while thermal annealing gradually reduced the size of the Cr segregation phase until it dissolved. The presence of divacancy defects in the deformed samples increased the diffusion of Cr atoms and caused Cr segregation.
Article
Polymer Science
Mohammed Al Otmi, Frank Willmore, Janani Sampath
Summary: Polymers are attractive materials for membranes due to their mechanical robustness and cost-effective fabrication. The performance of membranes is influenced by free volume elements (FVEs), which tend to degrade over time. Understanding the relationship between chain dynamics and FVE distribution can lead to more efficient regulation of penetrant transport in amorphous polymer membranes.
