Poly(lactic acid)/cellulose nanocrystal composites via the Pickering emulsion approach: Rheological, thermal and mechanical properties

The use of nanocellulose is an attractive method to improve the characteristics of biodegradable polymers, but its effects are often affected by uneven dispersion. In this work, cellulose nanocrystals (CNCs) were evenly dispersed into poly(lactic acid) (PLA) via the Pickering emulsion approach. The PLA/CNC composites prepared were studied by rheological, thermal as well as mechanical measurements. Changes in the rheological characteristics of the composites showed that CNC promoted the transition of the composites from fluid to solid-like behavior at high temperatures. The introduction of 5 wt% CNC improved the crystallinity of PLA considerably and increased the onset temperature of crystallization by about 10 °C. The storage modulus of the composites increased throughout the entire temperature range of testing. Flexural modulus was improved considerably. All the results indicated that the Pickering emulsion approach improved the dispersion of CNC in the PLA matrix and CNC improved efficiently most properties of PLA

Poly(lactic acid)/lignin blends prepared with the Pickering emulsion template method

In this work, the Pickering emulsion template method was used to introduce lignin nanoparticles into poly(lactic acid) (PLA) with improved dispersion. The effect of lignin as the stabilizer of Pickering emulsions was studied in this paper, including the thermal, rheological and mechanical properties of the blends. The PLA/lignin films had reduced light transmission in the UV light region, and Young’s modulus of PLA/lignin blends increased, while their tensile strength and elongation-at-break decreased as compared to neat PLA film. The introduction of lignin improved crystallinity of PLA from 7.5% to over 15%, and increased its decomposition temperature by about 10 °C. The lignin in the blends prepared using the Pickering emulsion template approach had much larger load bearing capacity than the dispersed lignin particles in the usual melt blended material. All the results indicated that the Pickering emulsion template method improves the dispersion of lignin (over 5.0 wt%) in PLA and improves UV protection, crystallinity, decomposition temperature and Young’s modulus of PLA

A Comparative Study of Emergency Coverage on People's Daily Newspaper and Its Sina Weibo account - In the case of the "TianjinExplosion"

AbstractIn current society, social media play an increasingly important issue role. When Emergencies Occur, They exert great influence on the society, as well as on the traditional media. This research AIMS at Contributing to a more comprehensive understanding of the differences between the traditional mass media and the social media Regarding the news coverage of social emergencies, in particular, the Chinese environment. The objects of this research are the People's Daily Newspaper -the most influential newspaper in China and its Sina Weibo account - @ People's Daily. I chose Sina Weibo as one of the media platforms of ice Because of it is the most popular microblogging portal in China and has great influence among Chinese people. In this thesis, crisis communication is used as the theoretical framework. Content analysis is used as the method to analyze the Collected Data. A specific event- "Tianjin Explosion" has been chosen to conduct the research. The result of the research indicates thatthere are some similarities and differences of the emergency coverage on the People's Daily Newspaper and @ People's Daily. Both media platforms focus on the crisis-stage and paid attention to the dissemination of the information about the emergency itself. However, the People's Daily Newspaper has stronger government control than @ People's Daily, and mostly speaking for the government, did not show much attention to the AFFECTED people and Their Families, Whereas posts on Sina Weibo are more sympathetic and there are more critical posts on @ People's Daily. Another difference Is that news on @ People's Daily is timelier than the People's Daily Newspaper. Furthermore, this thesis Also Provides some suggestions about how the media Should be improved in covering social emergencies in the future.Keywords: People's Daily, traditional media, social media, social emergency

Construction and Thoughts of Intelligent “Three-Prevention” System in Shenzhen

Modern science and technology is a weapon against natural disasters. Shenzhen is a city of technology and innovation and we should endeavor to address flood control, drought relief and wind mitigation (named “three-prevention” in this context). In particular, we should vigorously promote the improvement of technology, and make use of modern information technologies such as big data, internet of things, cloud computing and artificial intelligence to create intelligent three-prevention system. This paper described in detail the characteristics and the construction status of the intelligent three-prevention system as well as the future development direction, in order to achieve the construction goals of the overall situation probing of the three-prevention, real-time decision-making assistance, flat command and control and urban resilience development. Since the intelligent three-prevention system’s launch in April 2020, it has started more than 20 times of emergency response against typhoon and flood. The whole process functions of front-end intelligent perception, fine dynamic simulation, real-time forecast and early warning, emergency command and post-disaster assessment have been preliminarily realized

Fabrication of lignin/poly(3-hydroxybutyrate) nanocomposites with enhanced properties via a Pickering emulsion approach

The present-day world still demands for various commercially viable biosourced materials to replace the finite petroleum-derived polymers. Herein, lignin nanoparticles were homogeneously dispersed in the poly(3-hydroxybutyrate) (PHB) matrix via an economical, simple and environmentally friendly oil-in-water Pickering emulsion approach to form a nanocomposite with improved properties. The prepared lignin/PHB nanocomposites were investigated for their morphological, thermal, optical, rheological and mechanical properties. The lignin nanoparticles proved to be efficient nucleating agents for PHB in that they noticeably increased the crystallization rates of the polymer. PHB film containing 7% lignin demonstrated the optimum improvement in the tensile performance with 13.2% and 43.9% increase in tensile strength and Young's modulus, respectively. This upturn was ascribed to the uniform dispersion of the lignin nanoparticles and the formation of strong interfacial adhesion between the filler and the matrix due to hydrogen bonding interactions. Moreover, lower crystallinity, higher glass transition temperature, improved UV resistance/blocking and higher melt viscosity were achieved in the blends. The synergetic advancement in these properties may be of significant importance for the wider application of bio-sourced PHB in the packaging industry

Precipitated silica agglomerates reinforced with cellulose nanofibrils as adsorbents for heavy metals

Silicon-containing compounds such as silica are effective heavy metal sorbents which can be employed in many applications. This is attributed to the porous nature of hydrothermally-stable silica, endowing such materials with high surface area and rich surface chemistry, all responsible for improving adsorption and desorption performance. However, to this day, the wide application of silica is limited by its skeletal brittleness and high production cost coupled with a risky traditional supercritical drying method. To solve the named problems, herein, precipitated silica agglomerates (referred to as PSA) was crosslinked with TEMPO-oxidized cellulose nanofibrils (TO-CNF) as a reinforcement in the presence of 3-aminopropyltriethoxysilane (APTES), via a facile dual metal synthesis approach, is reported. The resultant new silica-based sponges (TO-CNF PSA) showed desirable properties of flexibility, porosity and multifaceted sorption of various heavy metals with re-usability. The experimental results showed maximum adsorption capacities of 157.7, 33.22, 140.3 and 130.5 mg g−1 for Pb(II), Hg(II), Cr(III) and Cd(II) ions, respectively. Such a facile approach to modify silica materials by attaching active groups together with reinforcement can provide improved and reliable silica-based materials which can be applied in water treatment, gas purification, thermal insulation etc.</i

Making polymers colored and stiffer by dyed regenerated cellulose employing Pickering emulsions

We demonstrate the successful use of Pickering emulsions utilizing regenerated cellulose that carry covalently immobilized dye molecules as emulsifiers to color PMMA and enhance its mechanical performance. Due to the use of this biobased dye carrier, the materials we describe exhibit enhanced “green” character. First we show that oil-in-water Pickering emulsions of PMMA can be effectively stabilized by dyed regenerated cellulose. We describe how uniformly colored PMMA-cellulose composites with high transparency in the visible range can be obtained. We provide detailed characterization of the resulting composites. Thermogravimetric analysis shows an increase of onset of degradation temperature, thus indicates improved thermal stability. Also the mechanical properties become improved, as indicated by flexural strength enhancement. The Pickering emulsion-based procedure is simple and cost effective, and could be easily adopted to prepare other polymer-nanocomposite systems

Live-cell imaging-based dynamic vascular formation assay for antivascular drug evaluation and screening

Summary: New vessel formation (angiogenesis) is an essential physiological process for embryologic development, normal growth, and tissue repair. Angiogenesis is tightly regulated at the molecular level. Dysregulation of angiogenesis occurs in various pathologies and is one of the hallmarks of cancer. However, most existing methods for evaluating cell vascular formation are limited to static analysis and prone to bias due to time, field of vision, and parameter selection. Code scripts, such as AngiogenesisAnalyzer.ijm, AutomaticMeasure.ijm, and VM.R., were developed to study the dynamic angiogenesis process. This method was used to screen drugs that could affect the time, maximum value, tilt, and decline rate of cell vascular formation and angiogenesis. Animal experiments have confirmed that these drugs could inhibit the formation of blood vessels. This work provides a new perspective for the research of angiogenesis process and is helpful to the development of drugs related to angiogenesis

Highly Stable and Nonflammable Hydrated Salt-Paraffin Shape-Memory Gels for Sustainable Building Technology

Hydrated salts (salt hydrates) are highly promising low-temperature phase change materials (PCMs) due to their high cohesive energy density and low cost. However, they exhibit phase separation, liquid leakage, and inherent supercooling, which hinder their applications in sustainable building technology. Here, we describe the design of a highly stable emulsion gel system (EmulGels) that exhibits nonflammable and shape-memory characteristics. Oleophilic paraffin and hydrophilic hydrated salts, both of which are excellent PCMs typically existing in separate phases, are combined harmoniously in a gel by a templating water-in-oil Pickering emulsion. Latent heat values of the prepared EmulGels were up to 213.2 J/g (eicosane/disodium hydrogen phosphate dodecahydrate = 1:3). No leakage of eicosane was noticed after heating the EmulGels at 60 °C for 30 min, and the latent heat value remained almost unchanged following 500 thermal cycles. The EmulGel was specifically designed to enable dual-phase crosslinking, which effectively enhanced its shape stability, slowed down loss of water of crystallization in hydrated salts, and decreased the degree of supercooling. Nonflammable characteristic typically found in hydrated salts was also exhibited by the EmulGel, in combination with good mechanical properties. The materials characteristics make EmulGels ideal candidates to serve as building construction interlayers for effective thermal building management