24 research outputs found
Bio-Based Porous Aerogel with Bionic Structure and Hydrophobic Polymer Coating for Efficient Absorption of Oil/Organic Liquids
Increasing contamination risk from oil/organic liquid leakage creates strong demand for the development of absorbents with excellent hydrophobicity and absorption capacity. Herein, bagasse was carbonized to form porous char with a special structure of array-style and vertically perforated channels, and then the activation process enlarged the pore volume of the char. With the cooperation of low-surface-energy polydimethylsiloxane and diatomaceous earth particles, the modified activated carbon aerogel (MACA) was fabricated by modifying the surface coating and mastoid structure on the bagasse char. Moreover, the MACA demonstrates high porosity oil-water separation, hydrophobicity, and considerable absorption capacity (4.06–12.31 g/g) for gasoline and various organic solvents. This work converts agricultural waste into an efficient porous adsorbent, offering a scalable and commercially feasible solution to solving the leakages of oil/organic solvents
Flame-retardant polyvinyl alcohol/cellulose nanofibers hybrid carbon aerogel by freeze drying with ultra-low phosphorus
Polyvinyl alcohol/cellulose nanofibers hybrid aerogel was prepared under freeze drying method. To improve the aerogels' anti-combustion performance, 0.8 wt% microencapsulated ammonium polyphosphate (MCAPP) was loaded as the flame retardant. Aerogels with extremely low density (~0.06 g/cm3) and excellent mechanical performance (Young's modulus: 1.045 MPa) can be obtained. The resulted aerogel also exhibit considerable thermal insulation ability (thermal conductivity: ~0.04 W/m·K). Experimental results indicate that the value of limiting oxygen index increases from 19.5% to 37.5% when loading 0.8 wt% MCAPP. Accordingly, the aerogels' peak heat release rate decreased significantly from 222.44 to 107.84 kW/m2. The char residue rises when introducing MCAPP and the char's integrity improves a lot after combustion. The fire performance index and fire growth index increases and falls respectively, indicating improved anti-combustion performance. X-ray photoelectron spectroscopy results show C[dbnd]O bonds would be increased for the esterification of phosphoric acid from MCAPP. In addition, the production of carbonate can be prohibited while combustion when loading MCAPP
Thermosonication Combined with Natural Antimicrobial Nisin: A Potential Technique Ensuring Microbiological Safety and Improving the Quality Parameters of Orange Juice
Currently, thermal pasteurisation (TP) remains the most widely applied technique for commercial orange juice preservation; however, a high temperature causes adverse effects on the quality attributes of orange juice. In order to explore a novel non-thermal sterilization method for orange juice, the impacts of thermosonication combined with nisin (TSN) and TP treatments on the quality attributes including microbial and enzyme inactivation and the physicochemical, nutritional, functional, and sensory qualities of orange juice were studied. Both TP and TSN treatments achieved desirable bactericidal and enzyme inactivation effects, and nisin had a significant synergistic lethal effect on aerobic bacteria in orange juice (p < 0.05). Additionally, TSN treatment significantly improved the color attributes of orange juice and well maintained its physicochemical properties and sensory quality. More importantly, TSN treatment significantly increased the total polyphenols content (TPC) and total carotenoids (TC) by 10.03% and 20.10%, increased the ORAC and DPPH by 51.10% and 10.58%, and the contents of total flavonoids and ascorbic acid were largely retained. Correlation analysis of antioxidant activity showed that the ORAC and scavenging ability of DPPH radicals of orange juice are mainly attributed to TC and TPC. These findings indicate that TSN shows great potential application value, which could guarantee the microbiological safety and improve the quality attributes of orange juice
Preparation of Large-Size Reduced Graphene Oxide-Wrapped Ammonium Polyphosphate and Its Enhancement of the Mechanical and Flame Retardant Properties of Thermoplastic Polyurethane
A facile
and novel approach is provided to improve the dispersion
of large-size reduced graphene oxide (LRGO) in a polymer matrix through
attachment on the surface of ammonium polyphosphate (APP) in the medium
of (3-aminopropyl) triethoxysilane (APTS). Here, a series of LRGO-wrapped
APP (named LRAPP) were first prepared and successfully characterized
and then blended into thermoplastic polyurethane (TPU). The introduction
of LRGO increased the interfacial adhesion between the APP and polymer,
thus achieving remarkable enhancement in mechanical and flame retardant
properties. Especially TPU/LRAPP1, where APP is encapsulated by 1%
LRGO, can obtain a huge increase in tensile strength and elongation
at break (189.7% and 24.6%, respectively) compared to those of TPU/APP.
In addition, LRAPP0.5 encapsulated by only 0.5% of LRGO could effectively
restrain the melt–dripping phenomenon in TPU composites and
acquired the lowest peak heat release rate value of 170.6 kW/m<sup>2</sup>. This novel strategy aims to broaden extensive application
of large-size graphene
Effect of Functionalized Graphene Oxide with Organophosphorus Oligomer on the Thermal and Mechanical Properties and Fire Safety of Polystyrene
A novel
organophosphorus oligomer was synthesized to functionalize
graphene oxide. Subsequently, the functionalized graphene oxide (FGO)
was incorporated into polystyrene (PS) to enhance the integration
properties of the matrix. The effect of FGO on the thermal properties,
fire safety, and mechanical properties of PS nanocomposites was investigated.
The results showed that the introduction of FGO significantly increased
the maximum decomposition temperature (<i>T</i><sub>max</sub>) (25 °C increase), reduced the total heat release (20.8% reduction),
and peak heat release rate (38.2% reduction) of PS. In addition, the
thermogravimetric analysis/infrared spectrometry analysis results
indicated that the amount of organic volatiles and toxic carbon monoxide
of PS was remarkably reduced. The physical barrier effect of FGO and
the synergistic effects between the organophosphorus oligomer and
FGO were the main causations for these properties improvements. Homogeneous
dispersion of FGO into the polymer matrix improved the mechanical
properties of FGO/PS nanocomposites, as demonstrated by tensile tests
results