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The development of a heat stabilizer with good thermal stability, plasticizing performance, and migration resistance for polyvinyl chloride (PVC) is still a notable challenge. In this work, two bio-based heat stabilizers, epoxidized cardanol oleate (ECD-OA) and epoxidized cardanol myristate (ECD-MA), were designed and synthesized with different lengths of their alkyl chains and different epoxy contents to provide outstanding compatibility with PVC. After confirming the chemical structures of ECD-OA and ECD-MA by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, the thermal stabilizing effects of both epoxidized cardanol esters were compared with those of the traditional CaSt2/ZnSt2 stabilizer and bio-based epoxidized soybean oil. Then, the effects of four different heat stabilizers on the mechanical, thermal, rheological, and optical properties of PVC films were fully studied. The results suggested that the ECD-MA showed the best thermal stability, and the PVC/30DOP/5ECD-MA film did not turn black after 2 h of thermal aging at 200 °C. In addition, the ECD-MA had good compatibility with PVC, and it had a synergistic plasticizing effect, which caused the film to have a high ductility and tensile strength (320.1% and 19.8 MPa, respectively). [ABSTRACT FROM AUTHOR]

Trisilanolphenyl-polyhedral oligomeric silsesquioxane titanium (Ti-Ph-POSS) was synthesized through the corner-capping reaction, and Ti-Ph-POSS was dispersed in benzoxazine (BZ) to prepare Ti-Ph-POSS/PBZ composite materials. Ti-Ph-POSS could catalyze the ring-opening polymerization (ROP) of BZ and reduce the curing temperature of benzoxazine. In addition, Ti immobilized on the Ti-Ph-POSS cage could form covalent bonds with the N or O atoms on polybenzoxazine, improving the thermal stability of PBZ. The catalytic activity of the Ti-Ph-POSS/BZ mixtures was assessed and identified through 1H nuclear magnetic resonance (1H-NMR) and Fourier-transform infrared (FTIR) analyses, while thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) were used to determine the thermal properties of the composite. It was found that PBZ exhibited a higher glass transition temperature (Tg) and better thermal stability when Ti-Ph-POSS was added. The curing behavior of the Ti-Ph-POSS/BZ mixtures showed that the initial (Ti) and peak (Tp) curing temperatures sharply decreased as the content of Ti-Ph-POSS and the heating rate increased. The curing kinetics of these Ti-Ph-POSS/BZ systems were analyzed using the Kissinger method, and the morphology of Ti-Ph-POSS/PBZ was determined via scanning electron microscopy (SEM). It was found that the Ti-Ph-POSS particles were well distributed in the composites. When the content exceeded 2 wt%, several Ti-Ph-POSS particles could not react with benzoxazine and were only dispersed within the PBZ matrix, resulting in aggregation of the Ti-Ph-POSS molecules. [ABSTRACT FROM AUTHOR]

The gel strength and thermal stability of fish gelatin are poorer than mammal gelatin. It's very important to improve the thermal stability which can sustain autoclave sterilization so as to expand the application of fish gelatin. In this study, 10% (w/v) tilapia skin gelatin sols with or without 1% (w/v) low acyl gellan gum were sterilized at 121°C before gelation, and the effects of autoclave sterilization on the textural properties and gel structures were investigated. The results showed that autoclave sterilization decreased the hardness (from 661.8 g to 505 g) and chewiness (from 27.44 mJ to 20.33 mJ) of the gels, which were raised more than four times by gellan gum. The gel point and melting point were increased from 16.7°C and 24.3°C to 40°C and 57°C respectively by gellan gum, both of which could sustain autoclave sterilization. Autoclave sterilization significantly decreased the relative intensity of the secondary structures and increased the interaction between proteins and water. The polypeptide chains in fish gelatin formed spherical aggregates and further formed a spatial network structure, which was destroyed by autoclave sterilization. Gellan gum prevented the damage by forming a continuous phase of a tight network that could sustain autoclave sterilization. So gellan gum strengthened the gelatin network and further increased the gel strength and gel point of the mixed gel. Novelty impact statement: The gel point and melting point of tilapia skin gelatin were lower than room temperature, which limited its application.Gellan gum significantly improved the gel properties and thermal stability of tilapia skin gelatin, both of which could sustain autoclave sterilization.Gellan gum formed a continuous phase of a tight network in the mixed gel, which strengthened the gel structures and would not be damaged by autoclave sterilization. [ABSTRACT FROM AUTHOR]

Three bis(phenyl)fluorene-based cardo diamine monomers with different side groups (–CF3, –H, and –CH3) were synthesized and used to synthesize three 6FDA-based polyimides (6FDA-FBPF, 6FDA-BPF, and 6FDA-MBPF). The influence of bis(phenyl)fluorene cardo moiety and different side groups on the glass transition temperature (Tg), thermal stabilities, and chain packing of the synthesized polyimides were systematically studied. The gas permeabilities and selectivities of three bis(phenyl)fluorene-based polyimide membranes were studied and correlated with their fractional free volumes and chain packing conditions. As a result, the obtained polyimides showed promising performance for hydrogen separation. Among the three polyimides, 6FDA-FBPF had the highest gas permeabilities which exhibited H2 permeability of 151.12 Barrer and H2/CH4 selectivity of 62.19. The high gas separation performance of 6FDA-FBPF mainly attributed to the ineffective chain packing via the incorporation of bi(phenyl)fluorene cardo moiety and introduction of bulky CF3 side groups into the polyimide backbones that is favorable to formation hourglass-shaped pores. [ABSTRACT FROM AUTHOR]

The development of a bio-based plasticizer with good plasticizing performance, migration resistance, and thermal stability for polyvinyl chloride (PVC) is still a notable challenge due to the trade-off between molecular weight and compatibility. Herein, epoxidized isosorbide-based esters featuring multiple epoxy groups were prepared via the esterification of isosorbide with various aliphatic acids with C-18 alkyl chains (oleic acid, linoleic acid, and linolenic acid) followed by epoxidation. The resulting epoxidized isosorbide-based esters were utilized as PVC resin plasticizers, and the overall performance of these plasticized PVC specimens was investigated in detail. Moreover, the esterification reaction was optimized and 1-propylsulfonic-3-methylimidazolium hydrogensulfate ionic liquid was selected as the catalyst. After the reaction was complete, the ionic liquid and product were in separate phases, enabling facile catalyst recycling in a simple, convenient, and environmentally friendly process. The most superior plasticizing effect was achieved by epoxidized isosorbide linolenate (EGLA-ISB). In comparison to the PVC samples plasticized with dioctyl terephthalate (DOTP), those plasticized with EGLA-ISB demonstrated a 15-fold increase in thermal stability during isothermal testing (a PVC/50EGLA-ISB film had a low weight loss of approximately 1.5% after heating at 200 °C for 120 min). Furthermore, the initial thermal decomposition temperature of the PVC plasticized by EGLA-ISB increased by almost 40 °C (up to 306.9 °C) compared to pure PVC, and a higher elongation at break (387%) was also observed. The excellent performance of the PVC plasticized by EGLA-ISB was attributed to the C-18 alkyl chains and multiple epoxy groups of EGLA-ISB, which improved its PVC compatibility, enhanced the thermal stability of the PVC. [Display omitted] • EGLA-ISB was prepared via the esterification of isosorbide with linolenic acid and followed by epoxidation. • 1-Propylsulfo-3-methylimidazolium hydrogen sulfate ionic liquid was chosen as the catalyst for the esterification reaction. • After the reaction was complete, the ionic liquid and product were in separate phases, enabling facile catalyst recycling. • PVC/50EGLA-ISB film has a low weight loss of approximately 1.5% after heating at 200 °C for 120 min. • EGLA-ISB avoids the trade-off between molecular weight and compatibility. [ABSTRACT FROM AUTHOR]

The influences of current density and saccharin concentration on nanocrystalline nickel coatings synthesized by direct current electrodeposition were analyzed. Results show that in the current density range from 0.5 A/dm 2 to 1.5 A/dm 2 , nanocrystalline nickel coatings with broad microhardness HV distribution from 4150 MPa to 6030 MPa can be synthesized by adjusting saccharin concentration. The preferred orientation in the deposits exists at 0.5 A/dm 2 , (111), (200) double orientation texture changes to a (200) orientation texture as saccharin concentration and (200) intensity increase. The internal stresses of the samples prepared at 0.5 A/dm 2 decrease to nearly 0 MPa as saccharin concentration increases to 1.2 g/L. The results of DSC curves show that the grains start to grow until 600 °C and keep the thermal stability near to bulk nickel when grain sizes are in the range from 28 nm to 98 nm. However, when the grain size is 10 nm, the grains grow abnormally at 317 °C, and their thermal stability decrease sharply. [ABSTRACT FROM AUTHOR]