Green synthesis of ZSM-5 using silica fume and catalytic co-cracking of lignin and plastics for production of monocyclic aromatics

ZSM-5 with hierarchical pore structure was synthesized by a simple two-step hydrothermal crystallization from silica fume without using any organic ammonium templates.The synthesized ZSM-5 were oval shaped particles with a particle size about 2.0 μm and weak acid-dominated with proper Brønsted(B)and Lewis(L)acid sites.The ZSM-5 was used for catalytic co-cracking of n-octane and guaiacol,lowdensity polyethylene(LDPE)and alkali lignin(AL)to enhance the production of benzene,toluene,ethylbenzene and xylene(BTEX).The most significant synergistic effect occurred at n-octane/guaiacol at 1:1 and LDPE/AL at 1:3,under the condition,the achieved BTEX selectivity were 24%and 33%(mass)higher than the calculated values(weighted average).The highest BTEX selectivity reached 88.5%,which was 3.7%and 54.2%higher than those from individual cracking LDPE and AL.The synthesized ZSM-5 exhibited superior catalytic performance compared to the commercial ZSM-5,indicating potential application prospect.

A Unifi ed View of Carbon Neutrality:Solar-Driven Selective Upcycling of Waste Plastics

With the rapid development of plastic production and consumption globally,the amount of post-consumer plastic waste has reached levels that have posed environmental threats.Considering the substantial CO_(2)emissions throughout the plastic lifecycle from material production to its disposal,photocatalysis is considered a promising strategy for eff ective plastic recycling and upcycling.It can upgrade plastics into value-added products under mild conditions using solar energy,realizing zero carbon emissions.In this paper,we explain the basics of photocatalytic plastic reformation and underscores plastic feedstock reformation pathways into high-value-added products,including both degradation into CO_(2)followed by reformation and direct reformation into high-value-added products.Finally,the current applications of transforming plastic waste into fuels,chemicals,and carbon materials and the outlook on upcycling plastic waste by photocatalysis are presented,facilitating the realization of carbon neutrality and zero plastic waste.

Promoting sustainable consumption and circular economy:the intention of Vietnamese youth consumers to purchase products made from recycled plastics

Recycling is viewed as a key component in a circular economy and serves as an ideal solution for promoting sustainability.During the global plastic crisis,plastic recycling practices have been adopted worldwide,leading to the production of various products made from recycled plastics(PRP).Nevertheless,a gap persists between consumption and demand for such products,which is primarily attributed to a lack of comprehension from the consumer perspective.Given the pivotal role consumers play in the adoption of these products,this study explores consumers’intentions to purchase PRP.This is particularly significant in Vietnam,which is an emerging economy aspiring to achieve the objectives of a circular economy and sustainable development.Utilizing an integrated cognitive-emotional framework comprising the Valence Theory and the Norm Activation Model,data from 564 Vietnamese students were gathered and analyzed using structural equation modeling.The results show that awareness of consequences is a major driver of consumer purchase intentions,followed by perceived ease of application and monetary incentives.The results also indicate that health concerns have the strongest effect on purchase intention and in the negative side,meaning that the health-related risk is the primary concern for consumers during the decision-making process.This research holds substantial value for academics and managers,as it aids in the theoretical exploration and the formulation of strategies to improve consumer acceptance of PRP.

Low-Density Microplastics in Recreational Parks of Al Ain, United Arab Emirates: Abundance, Composition, and Potential Effects on Soil Health

Microplastics (MPs) have been an emerging concern due to their harmful effects on the ecosystem and are ubiquitous in various habitats, from marine to terrestrial environments. However, studies on the presence of MPs in recreational areas are limited. One of the previous works has reported that urban recreational parks are considered “sinks” for plastic debris, including MPs. In this study, low-density MPs (LD-MPs) in soil samples collected from recreational parks of Al Ain, United Arab Emirates (UAE) were isolated by density flotation method. Results showed that these parks have varying levels of LD-MPs caused by various anthropogenic activities, such as sludge use and application of reclaimed water from wastewater treatment facilities in those areas. These plastic particles were isolated in 87% of the soil samples, with an average concentration of 1550 ± 340 MPs/kg. Predominantly, these comprised large LD-MPs (300 - 5000 μm), with red and blue being the most common colors. Fourier transform infrared (FTIR) spectroscopy identified possible synthetic polymers, including polyethylene and polypropylene. Additionally, a negative correlation was observed between LD-MP concentration and soil pH and moisture content, indicating potential adverse effects on soil health. These findings highlight the need for monitoring and managing microplastic pollution in urban recreational areas to mitigate its ecological impacts.

Wax from Pyrolysis of Waste Plastics as a Potential Source of Phase Change Material for Thermal Energy Storage

Over the past half-century, plastic consumption has grown rapidly due to its versatility, low cost, and unrivaled functional properties. Among the diff erent implemented strategies for recycling waste plastics, pyrolysis is deemed the most economical option. Currently, the wax obtained from the pyrolysis of waste plastics is mainly used as a feedstock to manufacture chemicals and fuels or added to asphalt for pavement construction, with no other applications of wax being reported. Herein, the thermal pyrolysis of three common waste polyolefin plastics: high-density polyethylene(HDPE), low-density polyethylene(LDPE), and polypropylene(PP), was conducted at 450 ℃. The waste plastics-derived waxes were characterized and studied for a potential new application: phase change materials(PCMs) for thermal energy storage(TES). Gas chromatography–mass spectrometry analysis showed that paraffin makes up most of the composition of HDPE and LDPE waxes, whereas PP wax contains a mixture of naphthene, isoparaffin, olefin, and paraffin. Diff erential scanning calorimetry(DSC) analysis indicated that HDPE and LDPE waxes have a peak melting temperature of 33.8 ℃ and 40.3 ℃, with a relatively high latent heat of 103.2 J/g and 88.3 J/g, respectively, whereas the PP wax was found to have almost negligible latent heat. Fourier transform infrared spectroscopy and DSC results revealed good chemical and thermal stability of HDPE and LDPE waxes after 100 cycles of thermal cycling. Performance evaluation of the waxes was also conducted using a thermal storage pad to understand their thermoregulation characteristics for TES applications.

Ni-catalyzed carbon–carbon bonds cleavage of mixed polyolefin plastics waste

The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C bonds in mixed polyolefin plastics over non-noble metal catalysts under mild conditions. The nickelbased catalyst involving Ni_(2)Al_(3) phase enables the direct transformation of mixed polyolefin plastics into natural gas, and the gas carbon yield reaches up to 89.6%. Reaction pathway investigation reveals that natural gas comes from the stepwise catalytic cleavage of C–C bonds in polypropylene, and the catalyst prefers catalytic cleavage of terminal C–C bond in the side-chain with the low energy barrier.Additionally, our developed approach is evaluated by the technical economic analysis for an economically competitive production process.

Making Plastics Greener and More Useful

Scientists from the Changchun Institute of Applied Chemistry of the Chinese Academy of Sciences(CAS)have developed a new way to make plastics to make it possible to be degradable in ambient environment with proper lighting.This move could help reduce plastic pollution.The new approach produces plastics from ethylene gas and carbon monoxide using specialized catalysts.This innovation incorporates two features to make the new-type plastics superior:the ability to degrade under ultraviolet light,and the new hydrophilic surface induced by introduction of new functional groups.The study was published in National Science Review(doi:10.1093/nsr/nwad039).

Javelin Plastics公司达到全球汽车标准

据“www．britishplastics．co．uk”报道，Javelin Plastics公司达到了ISO／TS16949：2009针对汽车部分的全球标准。达到这一标准将会给公司带来新的增长点，未来12个月销售额预计增长10％。自20世纪80年代中期成立以来，Javelin Plastics公司在包括汽车的多个市场领域经历了显著增长，从1997年公司开始按照ISO9001的规定进行生产管理，为客户提供关键安全部件、电子产品和家电等领域产品。

Co-pyrolysis characteristics of typical components of waste plastics in a falling film pyrolysis reactor

Waste plastics mainly come from MSW and usually exist in the form of mixed plastics. During the co-pyrolysis process of mixed plastics, various plastic components have different physicochemical properties and reaction mechanisms. Considering the high viscosity and low thermal conductivity of molten plastics, a falling film pyrolysis reactor was selected to explore the rapid co-pyrolysis process of typical plastic components(PP, PE and PS).The oil and gas yields and the compositions of pyrolysis products of the three components under different ratios at pyrolysis temperatures were analyzed to explore the co-pyrolysis characteristics of PP, PE, and PS. The study is of great significance to the recycling of waste plastics.

Degradable Plastics Are Vulnerable to Cracks

A plastic may degrade in response to a trigger.The kinetics of degradation have long been characterized by the loss of weight and strength over time.These methods of gross characterization,however,are misleading when plastic degrades heterogeneously.Here,we study heterogeneous degradation in an extreme form:the growth of a crack under the combined action of chemistry and mechanics.An applied load opens the crack,exposes the crack front to chemical attack,and causes the crack to outrun gross degradation.We studied the crack growth in polylactic acid(PLA),a polyester in which ester bonds break by hydrolysis.We cut a crack in a PLA film using scissors,tore it using an apparatus,and recorded the crack growth using a camera through a microscope.In our testing range,the crack velocity was insensitive to load but was sensitive to humidity and pH.These findings will aid the development of degradable plastics for healthcare and sustainability.

Photocatalytic conversion of waste plastics to low carbon number organic products

As a great threat to all livings on earth,waste artificial plastics now are everywhere,from oceans to our cells[1].The world cannot withstand the growing waste plastic in million tonnes every year,which has already caused environmental pollution and economic losses[2].Besides the efforts for preparing novel plastics with the self‐decomposition ability,methods are needed to clear away these waste plastics leftover from history or recycle well this organic carbon resource[3].Photocatalysis is a potential solution for the conversion of waste plastics under mild conditions.In this perspective,we highlight the effect of photocatalytic approaches toward the generation of low carbon number organic products(C_(n) products,n≤8)from waste plastics,which can proceed under an inert or aerobic atmosphere.Notably,critical analysis of the carbon source in products is necessary to reveal the active species for the C–X bonds(X=C,N,and O)cleavage of plastics.Finally,we outline potential avenues for further development of this emerging field to enhance the yield of C_(n)(n≤8)products from waste plastics.

The latest progress in research of plastics processing technology

According to the great demand for the＂ green＂ plastics processing technology of the low energy consumption, high efficiency and environmental protection in plastics industry, the plastics processing method and technology based on the elongation rheology, with continuing evolution and innovation of the plastics plasticating and conveying method, are presented and researched on the basis of the plastics dynamic processing method arid equipment, and the plastics plasticating and conveying process in the vane extrusion system, the technical characteristics and the applications of vane plasticating and conveying technology are discussed. The research results show that compared with the conventional processing equipment, this new technology and equipment shows many outstanding advantages, such as shortening the thermo-meehanical history of the plastics processing by more than 50 % , reducing the energy consumption by 30 % or so, improving the mixing and blending effects, improving the quality of the products and the adaptability to materials, etc. , and it is found that the new technology and equipment has special superiority in the fields of the processing for material systems, such as the multiphase and multicomponent composite materials, the shear heat sensitive macromolecular materials, etc.

Characterization of carbon fibers recovered through mechanochemical-enhanced recycling of waste carbon fiber reinforced plastics

In this study,we present the characterization of the carbon fibers recovered from the mechanochemical-enhanced recycling of carbon fiber reinforced fibers.The objectives of the study were to investigate the effect of our modified recycling method on the interfacial properties of recovered fibers.The reinforced plastics were recycled;the recycling efficiency was determined and the recovered fibers were sized using 1 wt%and 3 wt%concentration of(3-aminopropyl)triethoxysilane.We characterized the morphologies utilizing the electron spectroscopy for chemical analysis(ESCA),atomic force microscopy(AFM),FTIR-attenuated total reflection(ATR)spectroscopy and scanning electron microscopy(SEM).Although the surface of the fibers had no cracks,there was evidence of contaminations which affected the interfacial properties and the quality of the fibers.Results showed that the trends in the recovered and virgin fibers were similar with an increase in sizing concentration.The results highlighted the perspectives of increasing the quality of recovered fibers after the recycling process.

DETERMINATION OF EFFECTIVE MODULI FOR FOAM PLASTICS BASED ON THREE PHASE SPHEROIDAL MODEL

The relations of bulk modulus, shear modulus, Young's modulus and the Poisson's ratio with porosity of foam plastics are determined by a three phase spheroidal model commonly used in Composite Mechanics. The results are compared with those using differential scheme. It is shown that the material properties derived from the present model normally are larger than those obtained by differential scheme for foam plastics with identical porosity. The differences in shear moduli and Young's moduli obtained by the two methods are small but they are larger for bulk moduli of incompressible matrix and Poisson's ratios. The Young's moduli of high density foam plastics derived by the present model agree better with experimental ones.

Development and Properties of Glass Fiber Reinforced Plastics Geogrid

Glass fiber reinforced plastics geogrid has a wide application in the field of soil reinforcement because of its high strength, good toughness, and resistance to environmental stress, creep resistance and strong stability. In order to get high-powered glass fiber reinforced plastics geogrid and its mechanical characteristics, the properties and physical mechanical index of geogrid have been got through the study of its raw material, production process and important quality index. The analysis and study have been made to the geogrid＇s mechanical properties with loading speed, three-axial compression, temperature tensile test and FLAC3D numerical simulation, thus obtain the mechanical parameters of its displacement time curve, breaking strength and elongation at break. Some conclusions can be drawn as follows： （a） Using glass fiber materials, knurling and coated projection process, the f^acture strength and corrosion resistance of geogrid are greatly improved and the interlocking bite capability of soil is enhanced. （b） The fracture strength of geogrid is related to temperature and loading rate. When the surrounding rock pressure is fixed, the strength and anti-deformation ability of reinforced soil are significantly enhanced with increasing reinforced layers. （c） The pullout test shows the positive correlation between geogrid displacement and action time. （d） As a new reinforced material, the glass fiber reinforced plastics geogrid is not mature enough in theoretical research and practical experience, so it has become an urgent problem both in theoretical study and practical innovation.

Improving hydrocarbons production via catalytic co-pyrolysis of torrefied-biomass with plastics and dual catalytic pyrolysis

To increase the low yield and selectivity of aromatic hydrocarbons during the biomass pyrolysis process,we torrefied the biomass and then co-pyrolyzing with plastics such as high-density polyethylene(HDPE),polystyrene(PS),ethylene-vinyl acetate(EVA)and polypropylene(PP)and also single and dual catalyst layouts were investigated by Py-GC/MS.The results showed that non-catalytic fast pyrolysis(CFP)of raw bagasse(RBG)generated no aromatics.After torrefaction non-CFP of torrefied bagasse(TBG)generated low aromatic yield.Indicating that torrefaction would enhance the proportion of aromatics during the pyrolysis process.The CFP of TBG_(200℃)and TBG_(240℃)over ZSM-5 produced the total aromatic yield of 1.96 and 1.88 times higher,respectively,compared to non-CFP of TBG.Furthermore,the addition of plastic could increase H/Ceff ratio of the mixture,consequently,increase the yield of aromatic compounds.Among the various torrefied-bagasse/plastic mixtures,the CFP of TBG/EVA(7:3 ratio)mixture generated the highest the total aromatic yield of 7.7 times more than the CFP of TBG alone.The dual catalyst layout could enhance the yield of aromatics hydrocarbons.The dual-catalytic co-pyrolysis of TBG_(200℃)/plastic(1:1)ratio over USY(ultra-stable Y zeolite)/ZSM-5,improved the total aromatics yield by 4.33 times more than the catalytic pyrolysis of TBG_(200℃)alone over ZSM-5 catalyst.The above results showed that the yield and selectivities of light aromatic hydrocarbons can be improved via catalytic co-pyrolysis and dual catalytic co-pyrolysis of torrefied-biomass with plastics.

VISCO-ELASTIC (PLASTIC) EFFECTS AND FAILURE BEHAVIOR OF PUR FOAMED PLASTICS

ＶＩＳＣＯ┐ＥＬＡＳＴＩＣ（ＰＬＡＳＴＩＣ）ＥＦＦＥＣＴＳＡＮＤＦＡＩＬＵＲＥＢＥＨＡＶＩＯＲＯＦＰＵＲＦＯＡＭＥＤＰＬＡＳＴＩＣＳＬｕＺｉｘｉｎｇ（卢子兴）（ＩｎｓｔｉｔｕｔｅｏｆＳｏｌｉｄＭｅｃｈａｎｉｃｓ，ＢｅｉｊｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆ...

Novel technology of electroless Ni-W-P on plastics and its interface behavior

The electroless Ni-W-P coatings on polyoxymethylene(POM) were prepared. The POM was pretreated by hot spraying Al powder on it. Before the electroless Ni-W-P deposition, the POM with Al coating was flash plated in alkaline bath. The mechanism of Ni-W-P deposition was studied and the technology was optimized. The XRD analysis shows that the "as-deposited" Ni-W-P plating has mixed crystalline structure. The hardness value of deposits is more than HV700. The abrasion resistance of deposits is six times more than that of POM. Bending test was used to determine the cohesion between the deposits and the substrates. SEM was used to study the behavior of surface abrasion and interface bonding condition. The reason for the excellent cohesion was interpreted.

Critical Thrust Force Forecasting for Drilling Exit Delamination of Carbon Fibre Reinforced Plastics

Exit delamination is excessive drilling thrust force.Therefore,it is necessary to investigate the critical thrust force which cause exit delamination when carbon fibre reinforced plastics(CRFP)is drilled.According to the linear elastic fracture mechanics,the mechanics of composite material and the classical thin plate bending theory,a common theoretical model of the critical drilling thrust force for CFRP plates is established.Compared with the experimental data of previous studies,the results show that the theoretical values agree well with the experimental values.This model can be used to forecast the critical thrust force for the drilling-induced delamination of CFRP.

Experimental study on ductility improvement of reinforced concrete rectangular Columns retrofitted with a new fiber reinforced plastics method

Reinforced concrete （RC） columns lacking adequately detailed transverse reinforcement do not possess the necessary ductility to dissipate seismic energy during a major earthquake without severe strength degradation. In this paper, a new retrofit method, which utilized fiber-reinforced plastics （FRP） confinement mechanism and anchorage of embedded bars, was developed aiming to retrofit non-ductile large RC rectangular columns to prevent the damage of the plastic hinges. Carbon FRP （CFRP） sheets and glass FRP （GFRP） bars were used in this test, and five scaled RC columns were tested to examine the function of this new method for improving the ductility of columns. Responses of columns were examined before and after being retrofitted. Test results indicate that this new composite method can be very effective to improve the anti-seismic behavior of non-ductile RC columns compared with normal CFRP sheets retrofitted column.