Search

The accumulation of heat in electronic devices puts forward an urgent demand for thermal interface materials. It is still a great challenge to achieve the good comprehensive performance of high thermal conductivity (TC), insulation, flexibility and tensile strength. In this work, polyester‐based nonwoven fabric (NWF) was coated with boron nitride nanosheets (BNNS) by dispersion and interfacial reinforcement of cellulose nanofibers to obtain a three‐dimensional thermally conductive network skeleton (BNNS@NWF). The sandwich‐structured composite film was assembled by introducing alumina (Al2O3)/polydimethylsiloxane (PDMS) layers on the top and bottom surfaces of BNNS@NWF using scratch coating and hot pressing processes. The composite film has a high TC of 6.42 W/mK at 45.8 wt% BNNS content, and has excellent insulation with a volume resistivity of 1.06 × 1015 Ω cm. This is due to the long‐range effective thermal conduction path constructed by BNNS, the bridging effect of Al2O3 and the synergistic effect of the two fillers. PDMS helps the composite film maintain good flexibility and good TC stability after 30 bending cycles. The PET nonwoven interlayer gives the composite film good mechanical properties with a tensile strength of 17.5 MPa. This work provides a strategy for the efficient preparation of flexible composite films with high TC and insulation properties, which is of great importance for the development of innovative thermal interface materials. Highlights: A sandwich‐structured composite film was prepared by a simple scale‐up method.Al2O3 and BNNS achieves synergistic enhancement of thermal conductivity.The film has a high thermal conductivity of 6.42 W/mK and electrical insulation.The film shows good flexibility, high tensile and thermal management properties. [ABSTRACT FROM AUTHOR]

Nano-sized calcium carbonate was pretreated with silane coupling agent and then mixed with butyl acrylate that is of larger amount than the nanoparticles. Under γ-irradiation, graft polymerization occurred on the nanoparticle surface, forming a nanocomposite structure consisting of grafted poly(butyl acrylate) (PBA), homopolymerized PBA, and the segregated nanoparticles. It was found that the silane pretreatment significantly promoted the graft reaction. When the grafted nano-CaC[O.sub.3] particles were melt compounded with polypropylene (PP), an obvious synergistic effect, offered by (i) the chemical bonding between the elastomer type grafted PBA and nano-CaC[O.sub.3] and (ii) the deliberately introduced thick interlayer mainly constructed by the homopolymerized PBA, led to a significant increase in notch impact strengths and elongation to break of PP at a rather low content of nano-CaC[O.sub.3]. Meanwhile, the tensile stiffness of the composites was also slightly increased and the yielding strength of the composites was almost unchanged. The results are different from those with conventional rubber-toughened plastics, in which the improvement of ductility is acquired at high additive fraction and a great expense of strength performance. POLYM. ENG. SCI., 45:529-538, 2005. © 2005 Society of Plastics Engineers, INTRODUCTION Nanocomposites are attracting increasing research and market interest because of their potential for providing novel performance. It is believed that the tremendous interfacial area in a polymer nanocomposite helps [...]

BACKGROUND: Phytosterols are partly removed during oil refining, and the magnitude of phytosterols loss largely depends on the refining conditions applied and the molecular conformation. The aim of this research was to study the effect of deodorization conditions and molecular unsaturation on the esterification of phytosterols during deodorization of corn oil. RESULTS: In the chemical model, free fatty acids (FFAs) were the major provider of acyl groups during the formation of phytosteryl fatty acid esters (PEs) under deodorization conditions. Among the main parameters of the deodorization, temperature played a role in the formation of PEs with a time‐dependent manner. In comparison, saturated palmitic acid had a higher capability of esterifying free phytosterols (FPs) to PEs than unsaturated oleic acid and linoleic acid. Moreover, the influence of FFA unsaturation on the degradation of FPs depended on temperature. Besides, the formation of stigmasteryl ester had a competitive advantage over that of sitosteryl ester by quantum chemistry simulation. CONCLUSION: For laboratory‐scale deodorization of corn oil, saturated fatty acids and deodorization process with steam as stripping gas could obviously esterify FPs to PEs. FPs were abundantly enriched in distillate during the deodorization process with nitrogen as stripping gas, whereas FPs and PEs were distilled simultaneously during the deodorization process with steam. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

ABSTRACT Using dynamic mechanical analysis (DMA), we investigated the in situ crystallization kinetics of non-nucleated and nucleating-agent-treated isotactic polypropylene ( iPP) under continuous oscillatory shear during the entire crystallization process, and then compared the DMA results with those measured using differential scanning calorimetry under conventional quiescent crystallization. Our analyses, based on the Avrami equation, show that continuous oscillatory shear accelerated crystallization of non-nucleated iPP, but interfered with crystallization for nucleating-agent-treated iPP. Our results indicate that, for the present nucleating agent, its accelerating effect on crystallization cannot coexist with the accelerating effect of shear on crystallization. We attributed this difference to the disruptive effect of shear on growth and the different nucleation models of non-nucleated and nucleating-agent-treated iPP. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41685. [ABSTRACT FROM AUTHOR]

Abstract: This work is focused on properties improvement of polypropylene (PP) by incorporating ethylene–octene copolymer (POE) and nano-size calcium carbonate. Two types of CaCO3 nanoparticles (stearic acid treated and untreated) and two processing sequences (one-step and two-step mixing) were used to adjust the phase structure of the ternary composites. The experimental results indicated that the one-step mixing generated segregated dispersion of POE and CaCO3 nanoparticles in PP. The two-step process resulted in core-shell structures 100–200nm in size throughout the matrix, in which POE acts as the shell part encapsulating one or two nano-CaCO3. These specific phase structures were independent on the surface features of CaCO3 nanoparticles. In comparison with PP/POE blend or neat PP, notched impact toughness of the ternary composites of PP/POE/nano-CaCO3 was significantly increased. Meanwhile, stiffness and tensile strength of the latter were almost unchanged or slightly enhanced. It is believed that the synergistic effect of both the POE elastomer and CaCO3 nanoparticles should account for the balanced performance of the ternary composites. [Copyright &y& Elsevier]

BACKGROUND RESULTS CONCLUSION Sea buckthorn (Hippophae rhamnoides L.) pulp oil is rich in functional components; however, low water solubility and stability limit its applications. This study fabricated sea buckthorn pulp oil microcapsules using whey protein isolate (WPI), soy protein isolate (SPI), sodium caseinate (NaCN), gum arabic (GA), starch sodium octenylsuccinate (OSAS) and SPI mixed with chitosan (CHI). The influences of these wall materials on physicochemical properties, release behavior and digestibility were explored.Protein‐based wall materials (WPI, NaCN, SPI) demonstrated lower bulk densities due to their porous structures and larger particle sizes, while GA and OSAS produced denser microcapsules. Encapsulation efficiency was the highest for protein‐based microcapsules (79.41–89.12%) and the lowest for GA and OSAS. The surface oil percentage of protein‐based microcapsules (1.41–4.40%) was lower than that of the other microcapsules. Protein‐based microcapsules showed concave and cracked surfaces, while GA and OSAS microcapsules were spherical and smooth. CHI improved reconstitution performance, leading to faster dissolution. During simulated gastrointestinal digestion, protein‐based microcapsules released more free fatty acids (FFAs) in the intestinal phase, while CHI‐modified SPI microcapsules showed a delayed release pattern due to thicker walls.Protein‐based wall materials were more effective for sea buckthorn pulp oil microencapsulation, providing higher encapsulation efficiency, better flow properties and releasing more FFAs. The addition of CHI led to the layer‐by‐layer self‐assembly of the microcapsule wall and resulted in sustained release during in vitro intestinal digestion. These findings suggested the potential of protein‐based microcapsules for targeted delivery and improved applications of bioactive oils in the food industry. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd [ABSTRACT FROM AUTHOR]

• Elimination of zearalenone during oil refining process. • Alkali neutralization plays a role in the elimination of zearalenone. • Temperature plays a role on the zearalenone during alkali neutralization process of corn oil. • Mechanism of zearalenone degradation during alkali neutralization process was proposed. Zearalenone (ZEN) is one of the most widely distributed harmful mycotoxins produced by Fusarium species, especially deposited in corn oil. In this study, we systematically tracked the changes of ZEN in the refining of corn oil, and especially during neutralization process. An alkali neutralization process could remove certain amounts of ZEN that was much more than that of others refining steps. In a mimicking condition, ZEN contents decreased continuously and significantly with increasing neutralization temperature. However, when returned to neutral, recoverable ZEN decreased with increasing temperature, which confirmed more degradation of ZEN at high temperature. HPLC-Q/TOF MS and NMR evidence showed that non-reversible hydrolyzate followed decarboxylation was observed in a high-temperature alkali neutralization condition. The results may serve as the scientific basis for the elimination of zearalenone in refined vegetable oils, and provide clues to understanding the oil-safety aspects of elimination of zearalenone. [ABSTRACT FROM AUTHOR]

Phytosterol-based oleogels have been engineered in edible oils for potential applications as sustainable replacements for petrolatum. Oleogels have emerged with a crystal network structure with oil molecules trapped inside. In addition, the viscosity of highly thixotropic oleogels could be tuned by manipulating the concentration of phytosterols and monoglycerides, and the type of surface-active small molecules and bulk vegetable oils. Furthermore, viscous soft matter could also be tunably made with 8-20% oleogelators in olive oil with favourable water vapour occlusive and wettability properties, in addition to having good texture, and outstanding thixotropic and thermal reversibility properties. These properties are quite similar to those of commercial petrolatum. This work demonstrates that the natural phytosterol-oleogels in edible oils can be a novel source of sustainable and green replacements for petrolatum., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)