PLA has become a commodity polymer with wide applications in a number of fields. However, its high flammability with the tendency to flow in fire has limited its viability as a perfect replacement ...for the petrochemically-engineered plastics. Traditional flame retardants, which may be incorporated into PLA without severely degrading the mechanical properties, are the organo-halogen compounds. Meanwhile, these compounds tend to bioaccumulate and pose a risk to flora and fauna due to their restricted use. Research into PLA flame retardants has largely focused on organic and inorganic compounds for the past few years. Meanwhile, the renewed interest in the development of environmentally sustainable flame retardants (FRs) for PLA has increased significantly in a bid to maintain the integrity of the polymer. A review on the development of new flame retardants for PLA is presented herein. The focus is on metal oxides, phosphorus-based systems, 2D and 1D nanomaterials, hyperbranched polymers, and their combinations, which have been applied for flame retarding PLA are discussed. The paper also reviews briefly the correlation between FR loadings and efficiency for various FR systems, and their effects on processing and mechanical properties.
The process for preparation of UV-cured pigment/latex dispersion.
•UV-cured pigment/latex dispersion was prepared by miniemulsion polymerization.•Latex in UV-cured pigment/latex can fix each particle ...onto fabrics.•UV-cured pigment/latex ink provided fabrics excellent color fastness without damaging the handle.•The research combined the strengths of both UV-cured technology and miniemulsion polymerization.
UV-cured pigment/latex dispersions were prepared via miniemulsion polymerization, and further applied to formulate UV-cured pigment/latex inks for textile inkjet printing. FTIR, TEM and TGA results proved that the pigment was embedded into the latex. The increase in colorfastness of printed fabric indicated that the encapsulation layer of UV-cured pigment/latex could be enhanced by increasing the amount of styrene in polymerization. In addition, the prepared UV-cured pigment/latex inks were found to have excellent stability and jettability, and the printed cotton fabric showed high colorfastness and softness after UV irradiation. SEM images illustrated that the UV-cured pigment/latex inks formed a separate film on cotton fabric which was unlike the commercial pigment ink forming a continuous film. This research combined the strengths of both UV-cured technology and miniemulsion polymerization.
Fabricating high-performance MXene-based polymer nanocomposites is a huge challenge because of the poor dispersion and interfacial interaction of MXene nanosheets in the polymer matrix. To address ...the issue, MXene nanosheets were successfully exfoliated and subsequently modified by long-chain cationic agents with different chain lengths, i.e., decyltrimethylammonium bromide (DTAB), octadecyltrimethylammonium bromide (OTAB), and dihexadecyldimethylammonium bromide (DDAB). With the long-chain groups on their surface, modified Ti
C
(MXene) nanosheets were well dispersed in
,
-dimethylformamide (DMF), resulting in the formation of uniform dispersion and strong interfacial adhesion within a polystyrene (PS) matrix. The thermal stability properties of cationic modified Ti
C
/PS nanocomposites were improved considerably with the temperatures at 5% weight loss increasing by 20 °C for DTAB-Ti
C
/PS, 25 °C for OTAB-Ti
C
/PS and 23 °C for DDAB-Ti
C
/PS, respectively. The modified MXene nanosheets also enhanced the flame-retardant properties of PS. Compared to neat PS, the peak heat release rate (PHRR) was reduced by approximately 26.4%, 21.5% and 20.8% for PS/OTAB-Ti
C
, PS/DDAB-Ti
C
and PS/DTAB-Ti
C
, respectively. Significant reductions in CO and CO
productions were also obtained in the cone calorimeter test and generally lower pyrolysis volatile products were recorded by PS/OTAB-Ti
C
compared to pristine PS. These property enhancements of PS nanocomposites are attributed to the superior dispersion, catalytic and barrier effects of Ti
C
nanosheets.
The extemporaneous combustion of coal remains a major threat to safety in coal mines because such fire accidents result in casualties and significant property loss, as well as serious environmental ...pollution. This work proposed the fabrication of flame-retardant rigid polyurethane foam (RPUF) containing expandable graphite as char expander/sealant with melamine phosphosphate and 2-carboxyethyl (phenyl)phosphinic acid as char inducer and radical trapping agents. The as-prepared RPUF successfully inhibited coal combustion by forming thermally stable high graphitic content expandable intumescent char sealing over the coal. The RPUF achieved UL-94 V-0 rating in addition to significant reductions in peak heat release, total heat release, and CO and CO
yields. The external and the internal residual char structure was studied by X-ray photoelectron spectra, Raman spectroscopy, and real-time Fourier transform infrared spectra techniques, and a flame-retardant mode of action has been proposed. This work provides important insight into a facile fabrication of highly efficient and economical flame-retardant RPUF to inhibit the spontaneous combustion of coal.
The culture and artistic heritage of Ghana have been endorsed by the rich influence of Akan symbols like Adinkra, the akuaba doll, and others from various ethnic groups. However, the integration of ...ethnically unique near-extinct symbols into an art piece to highlight the cultural diversity of Ghana for wall hanging is rare. This work brings to life indigenous Ghanaian symbols on the verge of extinction from four ethnic groups, namely, the Akan, Ewe, Ga-Adangbe, and Mole-Dagbani to design a wall hanging for interior decoration, especially for public spaces by adopting Cora Marshal's aesthetico research to generate a "Quali-Aesthetico" model. The design aesthetically ingrained conceptual aboriginal art and near-extinct indigenous Ghanaian symbols from the four ethnic groups as inspiration. The creative integration of these symbols yielded an interesting art piece that provides a unique ambiance for a simulated interior-decorated airport and an art gallery suitably displayed on flat interior surfaces. Besides the artistic expression of the art piece, interpretations of the uniquely combined symbols and their philosophical meanings have been provided to educate the public about the rich Ghanaian cultural heritage. The art piece also seeks to preserve near-extinct identity symbols and create a sense of belonging for the younger generation.
Aqueous battery (AB) with non-metallic charging carriers is a viable candidate for grid energy storage devices owing to its comparatively low cost and high safety. However, developing practical ...electrode materials with remarkable electrochemical performance remains a great challenge. In this study, tungsten trioxide nanosheets (WONSs) with one-dimensional tunnels were facilely synthesized through a hydrothermal reaction. When used as the cathode material in aqueous batteries, the as-prepared WONS exhibits excellent long-term cycling stability and impressively high rate capability due to the nearly zero-strain structural characteristics of super-fast proton storage. Notably, a stable cycling performance with 89% capacity retention after 10000 cycles was achieved with an increased mass loading of WONS at around 12 mg cm−2. Our work points to a new direction of promoting high-efficiency AB applications with protons as charge carriers in a mild electrolyte.
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•WONS was utilized as cathode material against Zn anode in a neutral electrolyte.•Deep insights into the intercalation mechanism of protons in WONS cathode.•Proton cations for ABs expressively improve the rate performance.•WONSs demonstrate excellent cycling stability for 10000 cycles.
Vietnam's agricultural exports to China have remained strong, with the country maintaining its position as the top destination for Agri-products. This article primarily utilizes the Revealed ...Comparative Advantage (RCA) Index, and Trade Complementarity (TC) index to examine the trade comparative advantage, and the complementary of twenty major agricultural products between China and Vietnam from 2012 to 2021. The study results showed that Vietnam and China frequently exchange agricultural products. Vietnam has more stronger competitiveness than China in terms of agricultural products. China's exports to Vietnam were highly complementary to Vietnam's imports in category 0 whiles Vietnam's exports to China showed strong complementarity with China's imports in category 2. This paper analyzes the complementarity and comparative advantages of agricultural trade between China and Vietnam, and proposes informed suggestions for policy-making to promote agricultural trade between the countries. The proposed suggestions aim to expand agricultural trade between the two countries, reduce the trade imbalance, and achieve mutual benefit and win-win results.
As trade partners, China in East Asia and Ghana in Africa both play a major role in the China–Africa economic and trade cooperation and have strengthened their bilateral trade. The trade cooperation ...between China and Ghana has progressed, and there currently exists a large agricultural product trade between the two countries. China has become one of Ghana’s largest trading partners in recent decades, and bilateral cooperation has become stronger. This paper analyses the comparative advantage and complementarity of trade in agricultural products between China and Ghana in terms of twenty major agricultural products from 2016 to 2020, based on the revealed comparative advantage index, trade complementarity index, and their status quo. The results showed that the trade volume of China–Ghana agricultural products has continuously increased, and China is currently in a surplus state, but their total agriculture trade volume proportions had been decreasing. From the perspective of comparative advantage and complementarity, the results showed that the comparative advantage and complementarity coexist, but their comparative advantage is more obvious showing strong competitiveness. The result further shows that the comparative advantage of Ghana was stronger than that of China and the complementarity of China’s exports and Ghana’s imports of agricultural products has not been fully exploited; likewise, the complementarity of China’s imports and Ghana’s exports of agricultural products has not been fully exploited since 2018, and there is a large potential for further cooperation and development. Finally, based on the current situation and our analysis of agricultural trade between China and Ghana, suggestions were put forward to seek new and continuous development opportunities for agricultural trade cooperation between the two countries.
The zinc ion battery (ZIB) with mild aqueous electrolytes is one of the most promising systems for the large-scale energy storage application due to its high safety, environmental benignity, low ...cost, and high energy density. It exhibits excellent application potential and has attracted the attention of battery developers for grid energy storage demands in recent years. Compared with the numerous studies on the cathode materials for ZIBs, the research on the enhancement of the electrochemical performance of zinc metal anode is still in its early stage. The current challenges for Zn anodes are their poor cyclability and low Coulombic efficiency (CE) originated from the severe dendrite growth, self-corrosion, and irreversible byproducts formation. To address the intrinsic drawbacks of zinc metal anodes in mild aqueous electrolytes, some effective strategies, including interfacial modification between anode and electrolyte, structural design for Zn anodes and the adoption of novel separators and electrolytes, have been developed recently. This review aims to highlight the recent advances in Zn anode and outline future opportunities for the development of high-performance zinc metal anodes in aqueous ZIBs.
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•The application significance and development prospect of ZIBs are highlighted.•The strategies to enhance the electrochemical performance of zinc anodes are detailedly discussed.•The perspectives for the future development of high-performance zinc anodes are addressed.
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