Polymers (Basel)
Grupo de Polímeros, Departamento de Física y Ciencias de la Tierra, Escuela Universitaria Politécnica, Serantes, Universidade da Coruña, Avda. 19 de Febrero s/n, 15471 Ferrol, Spain.
Published: August 2022
Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) films were prepared using a cast film technique. Dioxane was chosen over other polymer solvents as it resulted in homogenous films with better morphology. Several plasticizers with different molecular weights and concentrations were added to the biopolymer solution prior to casting. Thermal, crystalline, and permeability properties were analyzed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and both water vapor and oxygen transmission rate analysis. In general, the addition of plasticizers decreased the glass transition temperature (T), cold crystallization temperatures (T), melting temperatures, as well as crystallinity degrees and increased the crystallite sizes and water vapor and oxygen transmission rates. The use of isosorbide and low-molecular-weight poly(ethylene glycol) (PEG) lowered the Tg around 30 °C at the highest used concentration, also being the most effective in increasing the crystallite size. When considering isosorbide and low-molecular-weight poly(ethylene glycol) (PEG) as very good plasticizers for PHBH, the question of which plasticizer to use strongly relies on the desired PHBH application.
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http://dx.doi.org/10.3390/polym14173503 | DOI Listing |
Food Chem
January 2025
School of Agricultural Engineering and Food Science, Shandong University of Technology, No. 266 Xincun Xilu, Zibo, Shandong 255049, China.
This study evaluated the effects of malic acid vacuum microwave preconditioning (MVMP) on lotus root (LR) by examining its moisture content, dielectric properties, microstructure, and starch characteristics, including modifications in starch structure and composition. Dielectric properties and LF-NMR indicated that the dielectric constant (ε') was closely associated to moisture content and state, while changes in water migration depended on microwave power and the dielectric loss factor (ε″). Increased microwave power and malic acid concentration resulted in microstructural damage (indentation and breakage of starch granules) and starch hydrolysis into smaller particles.
View Article and Find Full Text PDFDalton Trans
January 2025
Department of Chemistry, Jadavpur University, Jadavpur, Kolkata-700 032, West Bengal, India.
This study presents the synthesis of a Cd(II) based hydrophobic three dimensional crystalline network material (CNM), [Cd(L)(LH)(bpe)], {L = {4,4'-(hexafluroisopropylidine)bis(benzoate)} and 1,2-di(4-pyridyl) ethylene (bpe)}, 1(Cd), by employing the slow-diffusion method. The three-dimensional structure of 1(Cd) was determined by single crystal X-ray diffraction and characterized by powder X-ray diffraction (PXRD), FT-IR spectroscopy and thermogravimetric analysis (TGA). Subsequently, post-synthetic modification of 1(Cd) with Cu(II) at room temperature led to the formation of isostructural 1(Cu) with partial substitution.
View Article and Find Full Text PDFLayered double hydroxides (LDH) are compounds with unique structures of hydroxide functional groups on their surfaces, and they have the proper arrangement of divalent and trivalent cations to adjust their unique catalytic actions. LDH was synthesized utilizing the co-precipitation technique and was thermally treated at 300 °C. The prepared compounds were chemically and structurally elucidated using FT-IR, XRD, SEM, BET, TG-DTA, and XPS characterization.
View Article and Find Full Text PDFAppl Spectrosc
January 2025
Department of Chemistry, University of Utah, Salt Lake City, Utah, USA.
Crystallization from the melt is a critical process governing the properties of semi-crystalline polymeric materials. While structural analyses of melting and crystallization transitions in bulk polymers have been widely reported, in contrast, those in thin polymer films on solid supports have been underexplored. Herein, in situ Raman microscopy and self-modeling curve resolution (SMCR) analysis are applied to investigate the temperature-dependent structural changes in poly(ethylene oxide) (PEO) films during melting and crystallization phase transitions.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
Conventional dark-tone paints absorb both visible light and near-infrared (NIR) wavelengths, posing a challenge for light detection and ranging (LiDAR) recognition in autonomous driving. To overcome this issue, various chemical and structural coating materials have been explored to selectively reflect NIR. In this study, we newly propose colloidal photonic crystals with a stopband in the NIR range, fabricated through the spontaneous formation of crystalline arrays of silica particles dispersed in a photocurable resin, as a potential solution.
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