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A series of urethane-linked alkyl-cellulose was efficiently fabricated and served as a promising stabilizer for oil-in-oil Pickering emulsions.

The evolution of xylan-rich hemicelluloses (XH) aggregation behaviors in the presence of alkaline lignins (AL) under a wide range of pH values and NaCl concentration were investigated via dynamic light scattering and turbidity measurements. XH isolated from wheat straw contain a xylose backbone with arabinose side chains and a small amount of phenol groups. XH tend to aggregate in solution due to their low ratio of arabinose to xylose and hydrophobic phenol groups. AL interact with XH through the phenol groups bonded to the hemicellulose main chain to form an AL-XH complex. As the pH value decreases, the particle size and turbidity of AL, XH and their bonded complex all increase. The size of the AL-XH complex agglomerate is greater than the size of a XH at the same pH value, which indicates that the self-assembly of lignin molecules initiate the aggregation of XH. The particle size and turbidity of XH and AL-XH complexes increase as the XH concentration increase. At low pH values, e.g., 6.0, the particle size of the AL-XH complex more obviously increases compared to the XH particles. The size and turbidity of the AL, XH, and AL-XH complex agglomerates increased as the NaCl concentration increased.

Pressure sensors with desirable flexibility, robustness, and versatility are urgently needed for complicated smart wearable devices. However, developing an ideal multifunctional flexible sensor is still challenging. In this work, a composite aerogel film sensor with an internal three-dimensional (3D) microporous and hierarchical structure is successfully fabricated by the self-assembly of aramid nanofiber (ANF) and conductive MXene by vacuum-assisted filtration and ice crystal growth. The resultant MXene/ANF aerogel film with a mass ratio of 3/7 (30% MAAF) presents high robustness with an outstanding tensile strength of 14.1 MPa and a modulus of 455 MPa while retaining appealing flexibility and sensitive characteristics due to the 3D microstructure. Accompanied by superior electric conductivity, the MAAF sensor performs noticeably in human motion and microexpression detection with a fast response time of 100 ms and a high sensitivity of 37.4 kPa

The in-situ synthesis of calcium silicate in the fiber can not only meet the requirements for high loading of paper, but also make up and improve the reduction of paper performance caused by filling. In this investigation, the effects of pulp type, beating degree, fiber ratio, reaction time, rotational speed, dosage of lime milk and dispersant on calcium silicate loading and paper properties were investigated. The results showed that when the beating degree was 40 °SR, the ratio of softwood and hardwood pulp was 1:1, the reaction time was 60 min, the rotation speed was 600 r·min−1, the dosage of lime milk was 1.33 times of the theoretical amount, and the dosage of cationic polyacrylamide was 0.3 % (absolutely dry pulp), the ash content of hand-made sheet was 41.2 %, and the loading amount of calcium silicate was 26.3 %. Under this condition, the comprehensive performance of paper was the best.

Flexible paper-based sensors may be applied in numerous fields, but this requires addressing their limitations related to poor thermal and water resistance, which results in low service life. Herein, we report a paper-based composite sensor composed of carboxylic carbon nanotubes (CCNTs) and poly-m-phenyleneisophthalamide (PMIA), fabricated by a facile papermaking process. The CCNT/PMIA composite sensor exhibits an ability to detect pressures generated by various human movements, attributed to the sensor's conductive network and the characteristic "mud-brick" microstructure. The sensor exhibits the capability to monitor human motions, such as bending of finger joints and elbow joints, speaking, blinking, and smiling, as well as temperature variations in the range of 30-90 °C. Such a capability to sensitively detect pressure can be realized at different applied frequencies, gradient sagittas, and multiple twists with a short response time (104 ms) even after being soaked in water, acid, and alkali solutions. Moreover, the sensor demonstrates excellent mechanical properties and hence can be folded up to 6000 times without failure, can bear 5 kg of load without breaking, and can be cycled 2000 times without energy loss, providing a great possibility for a long sensing life. Additionally, the composite sensor shows exceptional Joule heating performance, which can reach 242 °C in less than 15 s even when powered by a low input voltage (25 V). From the perspective of industrialization, low-cost and large-scale roll-to-roll production of the paper-based sensor can be achieved, with a formed length of thousands of meters, showing great potential for future industrial applications as a wearable smart sensor for detecting pressure and temperature, with the capability of electric heating.

Paper-based products are similar to paper wasps’ “nests” built by “biofiber separation” and “biofiber reassembly”, where they add “saliva” for structural reinforcement and waterproofing. Rice leave...

Mineral fillers hinder cellulosic fiber bonding and thus limit the increase of filler content in paper. Herein, precipitated calcium carbonate (PCC)/cellulose nanofibrils (CNF) composites were fabricated by a facile and efficient strategy, i.e., co-refining process (CRP). During this process, CNF and PCC were activated by mechanochemical effect and formed encapsulation structure by calcium ion coordination and hydrogen bonding. The encapsulation structure and H-bond/ionic coordination interactions not only endowed the composite with excellent size stability but also enhanced interfacial interaction between composite fillers and cellulosic fibers. Compare with the paper filled with only PCC, PCC + CNF mixture, the tensile index of the cellulosic paper containing PCC/CNF composite was increased by 44.48% and 12.14%, respectively. These results not only provide a facile and scalable approach to increase interaction between cellulosic fiber and mineral filler but also create more possibilities for special paper-based materials with requiring high content of inorganic materials.

Aramid nanofibers (ANFs) have important applications in many fields, including electrical insulation and battery separators. However, a few limitations seriously restrict the application of ANFs currently, such as low preparation efficiency and the unclear preparation mechanism. To overcome these limitations, the present work proposes a new view-point from the perspective of reaction kinetics. The preparation efficiency was proven to essentially rely on the effective

Aramid nanofibers (ANFs) have been extensively explored in various fields since their emergence as high-performance nanoscale building blocks. ANF films exhibit strong sensitivity to ultraviolet (UV) irradiation which could deteriorate their performances. However, the sensitivity to UV irradiation has not been sufficiently understood yet. In this paper, for the first time, the surface structure and performance evolution of UV-irradiated ANF films are evaluated systematically. Results demonstrate that the fibrous nanofibers on the ANF films surface have been ultimately degraded into powdery nanoparticles, resulting from the chain scission, and the oxidation of amides groups in the ANFs. Moreover, newly formed anhydride has also been detected, which is derived from the chemical crosslinking of the oxidation products of the ANFs. Due to such structural evolution, some parameters of the ANF films display a downward trend within 72 h, and then a rising trend in the next 96 h. These parameters include the surface roughness, mechanical properties, water contact angles and temperature of weight loss at 10% (TG 10% ) of ANF films, while the crystallinity and temperature of maximum derivative weight curve (T max ) present opposite results.

Cellulose nanofiber (CNF) has faced challenges toward advanced applications due to the poor water resistance, wet strength, and poor thermal stability. The fabrication methods, morphologies and dispersibility between CNF and aramid nanofiber (ANF) were compared. Then the mechanical strength, especially the retention of wet strength (RWS), optical property, UV shielding, wettability and thermal stability of CNF and ANF nanopapers were further investigated. The results show that ANF and ANF nanopaper have significant advantages in dispersibility, water resistance, wet strength, thermal stability and UV-blocking ability over the CNF and CNF nanopaper. Especially the RWS of ANF nanopaper reached ˜82.5%, which notably exceeded the CNF nanopaper of 1.1%. This work demonstrates that the ANF could be an ideal alternative to CNF for advanced nanocomposites. Transparent, flexible, ultra-strong ANF nanopaper with favorable water resistance and wet strength, as well as good UV-blocking property shows great potential in variety of advanced applications.

The excess emission of toxic gases in atmosphere and heavy metal ions in drinking water is still a serious threat to human health. In this paper, a lightweight and porous zeolitic imidazolate frameworks-8@cellulose nanofiber@cellulose foam (ZIF-8@CNF@cellulose foam) with excellent gas adsorption and heavy metal ions removal properties was prepared using a simple in situ green growth method. The nitrogen adsorption property of ZIF-8@CNF@cellulose foam was 30 times higher than pure cellulose foam. Furthermore, the adsorption testing demonstrated that the composite foam showed high adsorption capacity for fluorescent dyes (24.6 mg g−1 for rhodamine B), heavy metal ions (35.6 mg g−1 for Cr (VI)) and organic solvents (45.2 g g−1 for DMF). Additionally, the ZIF-8/cellulose-based foam with 40 wt.% CNF exhibited an excellent mechanical performance, reaching a compressive strength value of 1.30 MPa. Herein, this work provides a feasible method to prepare ZIF-8@CNF@cellulose foam composite materials, which could adsorb gas molecules and heavy metal ions and show a great potential in atmosphere and water treatment.

A biodegradable cellulose-based air filter (Ag-MOFs@CNF@ZIF-8) with multi-layer structure was fabricated by in situ generation of double-component metal-organic frameworks (MOFs) and reinforcement of cellulose nanofiber (CNF). It exhibits good filtration performance, gas adsorption, antibacterial activity and mechanical property. The presence of MOFs could enhance the interaction between the filter and particulate matter (PM) and significantly improve the specific surface area of the composite filter. Thus, the filtration efficiency of the composite filter could reach 94.3% for PM2.5 and the nitrogen adsorption capacity increased to 109 cm3 g−1. Furthermore, the Ag-MOFs@CNF@ZIF-8 filter exhibited excellent antibacterial activity against Escherichia coli with an inhibition zone diameter of 18.1 mm. The compressive strength of the composite filter could be up to 501 kPa, approximately 3.8 times higher than that of pure cellulose filter. Herein, this composite filter has a great application potential in PM2.5 removal, toxic gas adsorption and healthcare fields.

Assembly of biofibers into paper-based products fits well into green chemistry principles. Biobased additives such as cationic starch and carboxymethyl cellulose are widely used in the paper industry. Edible additives, which often can be regarded as “safer” than regular biobased additives, may also play a role in tailorable design of paper-based products.

Para-aramid (PPTA) paper serves as the promising candidate for the heat-resistance insulating material and lightened-weight structure component due to its impressive mechanical property, inherent dielectric strength and thermal durability. However, the chemical inertness and the smooth surface of PPTA fibers lead to poor interfacial adhesion and inferior quality of PPTA paper. Here, for the first time, a facile and promising strategy to significantly improve the performances of the PPTA paper via incorporating the aramid nanofibers (ANFs) or laminating with the ANFs-film is proposed. The microstructures, mechanical properties, dielectric strength and reinforcing mechanisms of the resultant PPTA papers were investigated. PPTA paper with 6.0 wt% ANFs shows improved ultimate strength and dielectric strength (145.1% and 44.1% increases, respectively) than the pristine PPTA paper due to the interfacial bonding improvement of the ANFs serve as the bridging binders, fillers, inlaying nails and self-assembly films. Moreover, the adhesive-free ANFs-films laminated PPTA papers with tailored structures also exhibit remarkable mechanical and dielectric strength. The results indicate the great potential of ANFs or ANFs-film as a new class of reinforcements for PPTA paper, and also paves a promising way to fabricate high-performance paper-based nanomaterials, such as insulating materials and flexible display materials, etc.

Filler pre-flocculation has been extensively studied in the past to increase filler content while maintaining the physical strength properties of paper. However, optical properties of paper could be negatively affected due to the filler pre-flocculation. In this work, two kinds of precipitated calcium carbonate (PCC) fillers with different particle sizes, namely PCC1 (4.2 μm) and PCC2 (7.7 μm), were used to investigate the effects of filler pre-flocculation on the strength and optical properties of paper. Results showed that pre-flocculated fillers with smaller particle size (PCC1) could improve the tensile strength of handsheets more effectively, since the tensile index was increased by 22.9 %. Meanwhile, for a given floc size, the handsheets with PCC1 flocs exhibited a better light scattering ability comparing to the ones filled with PCC2 flocs. The improved light scattering ability of handsheets filled with 24 μm PCC1 flocs compared to 24 μm flocs produced with PCC2 can be attributed to the complex micro void structure of flocs. This finding can be used as a guidance for the selection of filler particle size when using filler pre-flocculation to optimize the mechanical and optical properties of paper.

In this study, polyimide (PI) chopped fibers were modified by ethylenediamine, and PI paper-based composites were fabricated using the as-modified PI chopped fibers and para-aramid fibrids which served as raw materials through the wet-forming process. The influence of different alkali treatment durations on the properties of PI fibers and composites was investigated. In sharp contrast with the pristine PI fibers, there was a satisfying difference in modified PI fibers including rougher surfaces and improved wettability due to the introduction of hydrophilic groups as confirmed by scanning electron microscope and Fourier transform infrared spectrometer. With increase in the modification time, the tensile index, the tearing index, and the internal bond strength of the composites were improved by 40.6, 27.0, and 103.57%, respectively, due to the hydrogen bonds. Meanwhile, the dielectric strength of the composites increased by 77.2% compared with the unmodified ones. These remarkable changes were mainly attributed to the enhanced interfacial bonding of the composites and decreased porosity in the three-dimensional network structure of the paper. Moreover, thermal stability was kept preferably within a certain range in spite of slight decrease.

In this study, SiO2 nanoparticles were in situ grown onto the surfaces of polyimide fibers via sol–gel synthesis and the corresponding paper-based composites were fabricated by wet-forming process using the as-obtained fibers as the starting materials. A simultaneous enhancement of the tensile and tearing index as well as the interlayer bonding strength of paper-based composites could be achieved with an increment of 17.7%, 17.2% and 50%, respectively. What is more, the dielectric strength of the resultant composites increased by 127% compared with the pristine paper-based composites. The results indicated that the SiO2 nanoparticles could be used as an excellent interfacial linker between the fibers and polymer matrix, and a smart cushion to release interior and exterior applied forces. Besides, satisfactory results on thermal stability of paper-based composites were attained after coated with SiO2 nanoparticles.

The use of mineral fillers in the paper industry has attracted much attention due to its low cost and ability to improve optical properties and printability. Besides the filler characteristics, paper properties, such as bulk, tensile, and opacity, are greatly affected by filler distribution in the z-direction. Therefore, optimization of filler distribution is an effective way to maximize the value of fillers. In this work, a filler distribution factor (Fc) was proposed to quantitatively describe the concentrated degree of filler distribution in the z-direction. The reduction in Fc resulted in an increase in paper bulk, porosity, and opacity, due to the generation of more interfaces between fibers and fillers. When filler particles were concentrated in one layer (Fc = 1), the tensile strength of the filled paper increased between 26 to 40% in comparison to the paper with various Fc values. For a given Fc, better tensile and opacity properties were achieved by increasing filler concentration on the surface layer of paper.

Developing engineered filler with special morphology to increase filler content and deliver paper desirable properties has been deserved much concern. In this work, two engineered calcium silicate fillers with different morphology, namely fly ash based calcium silicate (FACS), fibrous calcium silicate (FCS) were adopted to investigate the effect of filler morphology on paper properties, and natural wollastonite was used for comparison. It is found that FACS exhibits a wrinkled, porous surface while FCS reveals spherical agglomerates composed of needle-like particles. Physical tests demonstrated that in comparison with natural wollastonite with discrete shape, the aggregated porous structure of FACS and FCS showed noticeable improvement in bulk and opacity due to their high specific surface area (112 m2/g v.s 29 m2/g). At around 40 % filler content, the bulk of FACS and FCS filled handsheets increased 59.6 % and 43.8 %, respectively. The findings suggested that the engineered porous calcium silicate can be potentially used as paper filler in light weighted paper.

Green and biodegradable cellulose filters with controlled designer pore structures were prepared using organic solvent-based freeze casting. In this paper, the relationship between the different freeze media, including ethanol, isopropanol, and tertiary-butyl alcohol, and the microstructure of the porous filters was investigated. The results of the pore size distribution indicated that the pore channel size decreased remarkably when organic solvents were used as the freezing media. Moreover, the filters showed high filtration efficiencies, up to 99.70% and 99.66% for 0.5 µm and 0.3 µm particles, respectively, under a pressure drop of 180 Pa and at 32 L·min-1 flow rate. The fabrication of cellulosic filters would not only make it a promising candidate for capturing fine particulate matter, but also provide a versatile approach to regulate and design a porous structure for materials applied in various fields.

Core/shell structured composite particles have been frequently reported to enhance the performance of products. In this work, core/shell structured calcium silicate composite filler was prepared to mitigate the negative effect of calcium silicate filler on paper strength and allow for increasing filler content in paper. Calcium silicate as the core which was used as silica source, and reacted with hydrochloric acid to form SiO2 as shell. Results from XRD, FT-IR, SEM and BET specific surface area analysis indicated that nano-SiO2 particles were formed on the surface of calcium silicate. The active Si OH group on the surface of the composite filler enhanced the bondability between fillers and fibers. Physical testing of handsheets showed notable improvement in mechanical properties (tensile index increased 33.0%, tear index increased 18.1%). In addition, the Si OH group also helped to flocculate of composite filler to larger particles, which was also beneficial to the paper strength.

Poly(p-phenylene terephthalamide) (PPTA) paper serves as a promising matrix candidate that exhibits reduced overall weight and possesses exceptional inherent dielectric strength, thermal durability, and excellent mechanical property and processing flexibility. However, PPTA broken paper in mill is regarded as the solid waste and is landfilled eventually, resulting in severe environmental pollution and waste of resources. In this work, for the first time, an efficient and high value-added approach is proposed for the recovery of aramid nanofibers (ANFs) from PPTA broken papers by controlled deprotonation in KOH/dimethylsulfoxide (DMSO) system. A stable and uniform ANF/water dispersion and the insulating ANF films were successfully obtained. In an effort to explore those possibilities, the effect of ultrosonicon on the compact structure of PPTA broken paper was first investigated. Then the formation process, micromorphology, thermostability, crystalline structure and formation mechanism of ANFs, and the key...

Aramid nanofibers (ANFs) frequently are employed as versatile building blocks for constructing high-performance nanocomposites due to its structural and performance superiority. In this paper, the different ANFs and ANF films derived from the typical aramid yarns, chopped fiber, pulp fiber and fibrid fiber, respectively, were fabricated through deprotonation with potassium hydroxide in dimethyl sulphoxide, protonation with deionized water and vacuum-assisted filtration. The physical tests such as tensile test, ultraviolet transmittance and absorbance, thermogravimetric analysis were executed to evaluate and contrast the thermodynamic and optical performances of these differentiated ANFs and ANF films. The analytical results suggested that ANFs films prepared by the different forms of aramid macrofibers presented with differentiated properties such as mechanical behaviors, transparencies and flexibilities. And also it was found that the oversized nanofiber in length led to the formation of flocculation which was adverse for ANFs films in the formation of high strength. Whereas, small diameter just facilitated for the achievement of high stiffness and transparency. By contrast, the ANFs films made from chopped nanofiber, with aspect ratio of 200–500, exhibited good transparency, thermal stability and mechanical properties with transmittance value of 83%, TG10% around 521 °C, ultimate strength (σ) of 103.41 MPa, stiffness (E) of 4.70 GPa and strain at break of 5.56%. This work offers an alternative nanoscale building block as an effective nanofiller for preparing high-performance nanocomposites with different requirements in the potential fields such as transparent coating and flexible electrode or display materials, battery separator and microporous membrane.

The particulate matters (PMs) and toxic gases in air have resulted in serious impacts on public health. The development of “green” air filtering materials for isolating these pollutants is of vital importance. Here, we prepared a multi-functional cellulose-based air filter (CFs@ZIF-8 filter) by in situ growth of ZIF-8 nanocrystals on the surface of cellulose fibers. The incorporation of ZIF-8 nanocrystals increased the specific surface area of filter, strengthened the interactions between filter and PMs, and provided abundant cavities and gas adsorption sites for filter. The filtration efficiency of CFs@ZIF-8 filter for PM0.3 could reach to an ultrahigh level of 99.9%. The gas (nitrogen) adsorption capacity of CFs@ZIF-8 filter was 200 times higher than that of original cellulose-based filter (CFs-filter). The contributions of ZIF-8 on these surpassing properties of CFs@ZIF-8 filter were deeply analyzed. This study provided an effective strategy for developing “green” and multi-functional cellulose-based air filter.

In consideration of the healthcare issues caused by Particulate Matter (PM) pollution, developing high-performance air-filter materials especially aiming at filtering PM2.5 has attracted great attention. In this work, we fabricated a novel air filter with spider-web-like structure based on renewable and biodegradable fibrillated cellulose fibers, and demonstrated an effective strategy for network structure regulation during freeze-drying process. The results showed that the air filter with spider-web-like structure, whose filtration efficiency for model PM particles with the diameter of 300 nm could exceed 99%, was obtained from a fibrillated cellulose fiber/water/Tert-Butyl Alcohol (TBA) mixture by freeze-drying. The role of TBA in the construction of spider-web-like structure was mainly due to the following two aspects: (1) TBA molecules could promote the separation of microfibrils which acted as the cobwebs in spider-web-like structure. (2) The presence of TBA resulted in air filter transformed from lamellar porous architecture into spider-web-like structure by changing the morphologies and growth kinetics of ice-crystals. Herein, this work paves a way to fabricate high-performance air filters based on renewable materials and the pore-formation mechanism can provide a guide for structure regulation in porous materials.

The increase of filler content in paper is an effective way to reduce production costs and to promote the market competitiveness of paper mills. A shift from natural fillers to synthetic fillers has enabled improvements in the critical properties of paper. Meanwhile, innovations from single particles of filler to filler composites has made it possible to increase the filler content of paper. Among various filler innovations, the design of fiber/filler composites has aroused general attention from industry and academic researchers. However, concerns related to the cost and recyclability of composite fillers remain to be addressed.

A biodegradable cellulose-based air filter (Ag-MOFs@CNF@ZIF-8) with multi-layer structure was fabricated by in situ generation of double-component metal-organic frameworks (MOFs) and reinforcement of cellulose nanofiber (CNF). It exhibits good filtration performance, gas adsorption, antibacterial activity and mechanical property. The presence of MOFs could enhance the interaction between the filter and particulate matter (PM) and significantly improve the specific surface area of the composite filter. Thus, the filtration efficiency of the composite filter could reach 94.3% for PM

An aramid nanofibers (ANFs)-functionalized nanofibrillated cellulose (NFC) composite film is effectively fabricated by the incorporation of ANFs into nanocellulose matrix. The fabrication of the composite film imitates the traditional paper-making process after homogenous mixing. The as-prepared composite film shows excellent UV-shielding performance due to the incorporation of ANFs. Thus the effect of ANFs contents is evaluated in aspects of the surface morphology, physicochemical properties including crystallinity, chemical structure and photothermal stability of composite film. Results show that the composite film with 2 wt.% of ANFs has improved mechanical properties, surface wettability compared to pure NFC film, and presents excellent UV-shielding performance ranging up to 400 nm while still retaining its high transparency. Moreover, the composite film shows high photostability even after continuous UV irradiation (365 nm) for over 12 h. The findings in the present work indicate that the ANFs-functionalized NFC composite films are promising as UV-shielding and transparent materials.

Different modification routes using fly ash-based calcium silicate (FACS) with starch/sodium stearate were explored to mitigate the negative effect of filler on paper strength and allow for improved filler content. The morphology of the modified fillers and the properties of the filled paper were investigated. The modification route was found to be critical to the amount of starch/sodium stearate deposited on the surface of the filler particles. The most suitable modification route using FACS filler was as follows: starch (20% dosage on o.d. filler) was cooked, filler was added, and then sodium stearate was added (4% dosage on o.d. filler). The tensile index of the FACS-filled paper could be increased by 22% at 30% filler content under the best modification route. The brightness and bulk of the filled paper were also improved. However, the opacity of the filled paper was slightly decreased due to the deposition of starch/sodium stearate on the porous surface of the filler particles.

The development and application of low-cost and high-performance fillers by the paper industry is one of the most interesting aspects of filler technology. A novel calcium silicate, a byproduct, known as fly ashbased calcium silicate (FACS), from the value-added use of fly ash of coal-fired power plants, can be used as paper filler. To simulate the industrial papermaking process, a dynamic sheet former was used to evaluate the effect of FACS on the physical properties and printability of calendered paper. The results were compared with those of commonly used fillers, i.e., ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC). FACS-filled paper delivered a higher bulk than GCC-filled or PCC-filled papers at a given paper roughness. In addition, use of the original FACS exerted less influence on the tensile and tear strength of the filled paper. Printing quality tests indicated that at the same print density, the ink demand of FACS-filled paper was higher than that of GCC-filled or PCC-filled papers, but lower print through was obtained at the same amount of ink transferred to paper. The paper sheets containing the original FACS exhibited better surface strength than PCC-filled sheets. The results support the potential use of FACS as a low-cost filler for fine paper production.

In this paper, the mixed refining of fiber and a novel fly ash-based calcium-silicate (FACS) filler is proposed as a new filler application method, as it has some advantages over the traditional filling method. Paper produced using this filler application technique exhibits improved strength and optical properties but reduced bulk. SEM images were obtained to show the FACS filler-fiber composite structure that formed during the mixed refining process. Two models were proposed to describe the mechanism by which the mixed refining process improved the paper properties. Mixed refining can decrease the size of FACS particles, especially if the filler/fiber ratio is low. It was suggested that handsheets filled with small FACS particles had low bulk, which was beneficial for increasing the interfiber H-bonding. Decreasing the filler/fiber ratio improved the paper strength and optical properties at the expense of some bulk, a loss which varied depending on filler content.

Value-added utilization of fly ash has recently gained a strong interest. As a solid waste, fly ash can be used as a paper filler, and the recent innovation on the production of high-brightness fly ash products further facilitated such applications. This work reports the results on using the novel fly ash based fillers in the paper making process, with a focus on the effect of filler particle size. In comparison with ground calcium carbonate (GCC) commonly used as paper fillers, the original fly ash based calcium silicate filler (FACS) has a larger particle size (27.6 μm), a much lower true density (1.3–1.4 g/cm3), a higher specific surface area (121 m2/g), and a similar brightness (91% ISO). FACS exhibits porous, aggregated, and needle-like morphologies based on the results of scanning electron microscope image analysis. Ball milling decreased the particle size, broadened the particle size distribution, and improved the brightness while changing its morphology. The paper bulk increased dramatically when ...

A series of high trans -1,4-low- cis -1,4-high trans -1,4-stereotriblock polybutadienes (HTPB- b -LCPB- b -HTPBs) were synthesized through a sequential anionic polymerization of butadiene (Bd) initiated by barium salt of di(ethylene glycol) ethylether/triisobutylaluminium/dilithium (BaDEGEE/TIBA/DLi). The polymers consisted of elastic low- cis -1,4-polybutadiene (LCPB) chemically bonded with crystallizable high trans -1,4-polybutadiene (HTPB). The block ratios (HTPB:LCPB:HTPB) were designed at 25:50:25 (molar ratio) and finally determined by SEC. The microstructures and sequences of the specimens were investigated by FTIR and NMR. The resultant HTPB- b -LCPB- b -HTPBs consisted of LCPB block with 52.5% trans -1,4 content and HTPB block with 55.9–85.8% trans -1,4 content. According to differential scanning calorimetry (DSC), HTPB- b -LCPB- b -HTPB showed a significant cold crystallization which was discussed in terms of entanglement concept. The cold crystallization temperature ( T cc ) decreased whereas the melting temperature ( T m ) increased with the increasing trans -1,4 content of HTPB block.