Narrowly-Distributed Conjugated Polymers Synthesized through Suzuki Polymerization with Palladium(II) N-Heterocyclic Carbene Complex Confined in Dendritic Mesoporous Silica Nanoparticles.

A catalytic heterogenous Suzuki polymerization method was developed by confining the Pd(II)-catalyzed cross coupling reactions to take place exclusively in the nanochannels of dendritic mesoporous silica nanoparticles. Conjugated polymers with various monomer combinations, including donor-acceptor structures, were obtained in high yields. The molecular weights of the obtained polymers were well controlled with narrow molecular weight distributions (PDI value down to 1.13). All the polymeric products were highly soluble in common organic solvents, granting them with high processability. All the features of this confined Suzuki polymerization method endow the conjugated polymers great potential in optoelectronic applications.

N-Enriched Porous Carbon/SiO2 Composites Derived from Biomass Rice Husks for Boosting Li-Ion Storage: Insight into the Effect of N-Doping.

A N-enriched porous carbon/SiO2 (SiO2 /NC) composite from rice husks was prepared by ball milling and tested as a stable anode for lithium ion batteries (LIBs), in which the homogeneous dispersion of SiO2 nanoparticles and carbon matrix, and high level of N-doping can be realized simultaneously. The influence of N-doping on a series of SiO2 /NCs was systematically studied; this proved that the porosity, N-doping content, and electronic conductivity of SiO2 /NC can be controlled by adjusting common nitrogen sources (urea and melamine) and doping routes, including dry and wet milling, to reach a desirable balance of high capacity, long-term cyclability, and rate property. The optimized SiO2 /NC composite delivers a stably reversible capacity of 581 mA h g-1 at the high current load of 1.0 A g-1 at the 1000th cycle. The novel Li-storage mechanism of active silica in a composite was first proposed after observation of the N-doping effect that the redox reaction between SiO2 and Li+ is accelerated to transform into an alloying reaction of generated Si and Li+ , thus enhancing the reversible capacity. Moreover, kinetics analysis confirms that there is a combined Li-storage mechanism of battery-capacitive pattern in composite that contributes to fast charge transfer and ion diffusion during cycle.

Polymer Composite Thermoforming: Ultrasonic-Assisted Optimization for Enhanced Adhesive Performance in Automotive Interior Components.

Dual-component epoxy resins are widely used for bonding different materials in automotive interior processing. However, due to the complexity and variability of automotive interior parts, uneven temperature distribution on curved surfaces during the thermoforming process can lead to uneven thermal stress distribution, damaging the interior components. This study focuses on addressing the damage issues caused by uneven thermal stress distribution during the thermoforming of automotive interior components. By monitoring the temperature and strain on the adhesive surface of the interior components during processing, using sensors and combining the readings with a finite element simulation, damage to the adhesive during processing was simulated. Based on this, a segmented thermoforming method for the model surface was employed, but it was found that this method did not significantly reduce the level of damage to the adhesive during application. Building upon the segmented simulation, significant results were achieved by applying temperature modulation at a certain frequency to adjust the damage of the interior components during processing. The techniques used in this study successfully reduced the unevenness of the adhesive surface temperature, improved the performance of the adhesive during application through segmented optimization and the application of ultrasound-assisted techniques, and markedly reduced the manufacturing process's energy consumption.

Effect of Rice Husk-Based Silica on the Friction Properties of High Density Polyethylene Composites.

Rice husk ash (RHA)-reinforced composites are now used in many tribological applications. We prepared two kinds of RHAs using different pretreatment and the same pyrolysis process, namely water-treated RHA (WRHA) and acid-treated RHA (ARHA). Comparing the two RHAs, the RHA pretreated with hydrochloric acid (HCl) was found to have a smaller particle size and a more uniform dispersion. Accordingly, the two kinds of RHAs were used as fillers and added to the high-density polyethylene (HDPE) matrix by an extrusion process. The results showed that the friction coefficient (COF) value of the composites with ARHA was reduced to 0.12 when an additional amount of 0.75 wt.% or 1.5 wt.%. WRHA was used as a filler to the amount of 1.5 wt.%, but the COF value was raised to about 0.21. The reason for this phenomenon may be due to its larger particle size and more severe abrasive wear. This work provides a method for making natural biomass fillers that can effectively reduce the COF of HDPE composites with slight decreases in mechanical properties.

Turning lignin into treasure: An innovative filler comparable to commercial carbon black for the green development of the rubber industry.

Driven by the global carbon neutrality action, biomass-derived functional materials have been applied in many fields to alleviate the pressure brought by the depletion of fossil energy. However, due to the complex structure, lignin faces many difficulties in its high-value utilization. The second largest biomass in the world has become the largest "natural waste". In this paper, the lignin-based biochar-silica (LB-S) hybrid nanoparticles were prepared via a combination of two-step acid precipitation and carbonization using lignin black liquor extracted from xylose residue and sodium silicate as raw materials. The effects of carbonization temperature and lignin-based biochar (LB) content on the reinforcing properties of LB-S were studied. The results show that the particle size, specific surface area, pore characteristics, and surface polarity of LB-S all affect the mechanical properties of the final vulcanizates. The reinforcement performance of the best sample (LMB500-S) with "high structure" characteristics can be comparable to that of commercial carbon black (CB) N550. This study shows that LMB500-S hybrid nanoparticles with economic benefits possess the potential to completely replace commercial CB, which can turn lignin waste into treasure and promote the green development of traditional rubber industry in the context of carbon neutrality.

Controlled synthesis of conjugated polymers in dendritic mesoporous silica nanoparticles.

A controlled polymerization strategy is developed by confining the step-growth polycondensation to take place exclusively in the nanochannels of dendritic mesoporous silica nanoparticles. A variety of conjugated polymers with rich structural patterns were obtained in high yields. The molecular weights were precisely controlled with narrow molecular weight distributions. The obtained conjugated polymers were freely processed in solution and casted in film, showing bright fluorescence emission. All the features of this controlled polymerization method endow the conjugated polymers great potential for future applications.

Controllable conversion of biomass to lignin-silica hybrid nanoparticles: High-performance renewable dual-phase fillers.

Due to the complex network of aromatic units, lignin is difficult to achieve high-value applications in the industrial field, becoming the largest "natural waste". In this paper, dual-phase fillers with excellent rubber reinforcement were prepared from lignin and sodium silicate through the method of controllable two-step acid precipitation without any complicated modification. During the formation of hybrid nanoparticles, silica nanoparticles were formed as templates in the first step, and then lignin was used as coating agent to bind with silica. The size and morphology of products could be easily adjusted by changing acid precipitation conditions. The L60SS hybrid nanoparticles with the best reinforcement performance showed the ability to replace carbon black (CB) in a high proportion. In addition, LSRH-S hybrid nanoparticles made from rice husk black liquor had similar physical and chemical properties and excellent reinforcement properties to L60SS. Even if the ratio of each component of the raw material was different, the product could be flexibly controlled by the two-step acid precipitation to obtain the expected properties. The wide applicability of this method in many extraction processes based on alkaline procedures was proved, and it provided a basis for the process design of comprehensive utilization of biomass. This work will promote the application of lignin in high-value fields, and the sustainable development of the rubber industry by utilizing agricultural waste was achieved.

The Influence of Filler Size and Crosslinking Degree of Polymers on Mullins Effect in Filled NR/BR Composites.

Two factors, the crosslinking degree of the matrix (ν) and the size of the filler (Sz), have significant impact on the Mullins effect of filled elastomers. Herein, the result. of the two factors on Mullins effect is systematically investigated by adjusting the crosslinking degree of the matrix via adding maleic anhydride into a rubber matrix and controlling the particle size of the filler via ball milling. The dissipation ratios (the ratio of energy dissipation to input strain energy) of different filled natural rubber/butadiene rubber (NR/BR) elastomer composites are evaluated as a function of the maximum strain in cyclic loading (εm). The dissipation ratios show a linear relationship with the increase of εm within the test range, and they depend on the composite composition (ν and Sz). With the increase of ν, the dissipation ratios decrease with similar slope, and this is compared with the dissipation ratios increase which more steeply with the increase in Sz. This is further confirmed through a simulation that composites with larger particle size show a higher strain energy density when the strain level increases from 25% to 35%. The characteristic dependence of the dissipation ratios on ν and Sz is expected to reflect the Mullins effect with mathematical expression to improve engineering performance or prevent failure of rubber products.

Self-assembled lignin-silica hybrid material derived from rice husks as the sustainable reinforcing fillers for natural rubber.

Biomass derived fillers have been developed as sustainable substitution of carbon black (CB) used in rubber industry to reduce the dependence on fossil fuels. Lignin is the abundant component of biomass, but has poor reinforcing performance due to its huge particle size. In this work, we prepared a lignin/silica (LS) hybrid material from rice husks via a facile self-assembly method. The formation of LS cut lignin macromolecules into fragments and resulted in a small average particle size of 320 nm. When LS was filled into the natural rubber to substitute 10 phr CB, both filler-filler interaction and filler-rubber interaction were enhanced compared with the single use of CB. In consequence, the obtained 10LS/40CB/NR vulcanizates showed overall improvement in tensile strength, tear strength and abrasion resistance compared with the 50CB/NR vulcanizates. For the sustainable development of rubber industry, the natural LS hybrid material with low production cost is a promising reinforcing filler for the partial replacement of CB.

Surface Treatment Effects on the Mechanical Properties of Silica Carbon Black Reinforced Natural Rubber/Butadiene Rubber Composites.

For the first time, phenolic formaldehyde resin (PF)-treated silica carbon black (SiCB) were prepared with different treatment conditions and their effect as fillers on the mechanical properties of filler filled natural rubber/butadiene rubber (NR/BR) composites were investigated in detail. The PF coating layer on the SiCB derived from rusk husk not only promoted the dispersion of the fillers but also improved the interfacial interactions between fillers and the rubber matrix. As a result, both the cross-link density and mechanical properties of the obtained composites were effectively enhanced. The filler SiCB with 3 wt % PF surface treatment greatly improved the tensile strength of NR/BR composites and reached 7.1 MPa, which increased by 73.7% compared with that of SiCB-filled NR/BR composites. The improved interfacial interactions promoted higher energy dissipation, leading to simultaneously enhancing the glass transition temperature of the obtained composites. Due to the easy processing and low cost of filler as well as the effectively enhanced mechanical properties of composites, the PF-coating methodology has a great potential for practical applications in SiCB reinforced high-performance composites. A commercial filler, carbon black (N774), was also used in this study and evaluated under the same conditions for comparison.

Production of furfural from xylose at atmospheric pressure by dilute sulfuric acid and inorganic salts.

In this paper, the dehydration of xylose to furfural was carried out under atmospheric pressure and at the boiling temperature of a biphasic mixture of toluene and an aqueous solution of xylose, with sulfuric acid as catalyst plus an inorganic salt (NaCl or FeCl(3)) as promoter. The best yield of furfural was 83% under the following conditions: 150 mL of toluene and 10 mL of aqueous solution of 10% xylose (w/w), 10% H(2)SO(4) (w/w), 2.4g NaCl , and heating for 5h. FeCl(3) as promoter was found to be more efficient than NaCl. The addition of DMSO to the aqueous phase in the absence of an inorganic salt was shown to improve the yield of furfural.

Application studies of activated carbon derived from rice husks produced by chemical-thermal process--a review.

The production of functional activated carbon materials starting from cheap natural precursors using environmentally friendly processes is a highly attractive subject in material chemistry today. Recently, much attention has been focused on the use of plant biomass to produce functional carbonaceous materials, encompassing economic, environmental and social issues. Besides the classical route to produce activated carbons from fossil materials, rice husk shows clear advantages in that it can generate a variety of cheap and sustainable carbonaceous materials with attractive nanostructure and functional patterns for a wide range of applications. From a comprehensive literature review, it was found that porous carbon that derived from rice husks, in addition to having wide availability, has fast kinetics and appreciable adsorption capacities too. Porous carbon materials also play a significant role in new applications such as catalytic supports, battery electrodes, capacitors, and gas storage. In this review, an extensive list of rice husks literature has been compiled. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.

A sustainable route for the preparation of activated carbon and silica from rice husk ash.

An environmentally friendly and economically effective process to produce silica and activated carbon form rice husk ask simultaneously has been developed in this study. An extraction yield of silica of 72-98% was obtained and the particle size was 40-50 nm. The microstructures of the as-obtained silica powders were characterized by X-ray diffraction (XRD) and infrared spectra (IR). The surface area, iodine number and capacitance value of activated carbon could achieve 570 m(2)/g, 1708 mg/g, 180 F/g, respectively. In the whole synthetic procedure, the wastewater and the carbon dioxide were collected and reutilized. The recovery rate of sodium carbonate was achieved 92.25%. The process is inexpensive, sustainable, environmentally friendly and suitable for large-scale production.

A new route for preparation of hydrochars from rice husk.

In the present work, a green and sustainable route for preparation of hydrochars from sulfuric acid hydrolysis solution of rice husk under low temperature and atmospheric pressure was described. This route was achieved with the catalysis of sulfuric acid. The sphere-like carbon materials with regular size of about 500 nm were obtained at 95 degrees C for 6h when the acid concentration was 42% and 52%. The morphology of the hydrochars changed with sulfuric acid concentration increased. The surface of the materials contained a large number of functional groups. Furthermore, the localized graphitic nature of the materials was proved by X-ray diffraction pattern. High surface area porous carbons could be prepared from the hydrochars after activation, and they exhibited good electrochemical performance.

A facile synthesis of Cu(2)O/SiO(2) and Cu/SiO(2) core-shell octahedral nanocomposites.

We report here a simple approach to the synthesis of Cu(2)O/SiO(2) core-shell nanocomposites in water solution. The Cu(2)O cores have a perfect octahedral structure with uniform size of about 200-300 nm. A compact SiO(2) shell 9 nm in thickness is located at the surfaces of Cu(2)O octahedra, and it is composed of fine SiO(2) nanoparticles. During the depositing of the SiO(2) particles, as we presumed, dynamic absorbing and disengaging of Na(+) at the interface of Cu(2)O octahedra and the solution made it possible for the formation of Cu-O-Si bonds between core and shell in the composites. The existence of Cu-O-Si bonds in our core-shell composite can be substantiated by peak changes at 1236 and 1080 cm(-1) in the FT-IR spectra. This is the reason why the SiO(2) shell is so compact and uniform. Moreover, these Cu(2)O/SiO(2) core-shell octahedra were further used as precursors, depending on a simple disproportionation reaction of Cu(2)O in acid, to easily achieve Cu/SiO(2) movable multicore-shell octahedral nanocomposites. In the final Cu/SiO(2) core-shell composite, the thin SiO(2) octahedral shell was held, inside of which formed several free Cu nanoparticles 50-80 nm in size. Studies on the Cu(2)O/SiO(2) core-shell octahedral composites and Cu/SiO(2) movable multicore-shell octahedral nanocomposites would be a good thing not only for fundamental research but also for applications.