Tensile Index Research Articles

Production of recycled paper using harmless municipal sludge as a new biomass filler

Abstract Due to a shortage of resources, exploring new biomass fillers has become critical for paper making. In this study, we reported an eco-friendly strategy for fabricating low-cost and efficient recycled paper with high mechanical properties using corrugated cardboard waste paper and harmless municipal sludge (HMS). First, the characteristics of HMS, including the particle size, pH, specific surface area, organic functional groups and organic component content, were analyzed. Then, the influence of the amount of HMS on the properties of the recycled paper was studied. Finally, the strengthening mechanism of biomass filling recycled paper was discussed. The results showed that HMS, a biomass filler for recycled paper preparation, exhibited excellent physical and chemical properties, with a median particle size of 6.395 μm, a surface area of 39.974 m2 g−1 and organic functional groups. The tensile index of the recycled paper with 30 % HMS was 13.10 Nm/g, which was 16.4 % greater than that of the unfilled paper and showed better thermal stability. This excellent performance could be attributed to the uniform distribution of HMS on the fiber surface, which improved the accessibility of hydrogen bond formation between fibers. Thus, this study proved that HMS was an excellent biomass filler for producing recycled paper.

Flax biorefining for paper production

AbstractIn this work, we assessed the potential of Cel6D, a recently reported exocellulase from Paenibacillus barcinonensis, as a biorefining agent for flax pulp. Pulp fibers were treated with this enzyme, Cel9B (an endocellulase previously shown to possess biorefining action) and the two in combination. Samples of biorefined flax pulp were mechanically refined to obtain handsheets. All three biorefining treatments decreased air permeance in the handsheets. Cel9B increased tensile index and folding endurance, and the Cel6D − Cel9B combination increased tensile index and burst index but also resulted in markedly decreased tear index and folding endurance. On the other hand, Cel6D increased tensile index and burst index; also, more importantly, it increased tear resistance, albeit slightly, relative to the other two treatments. The results of this work can be useful to understand the differential effects of exocellulases and endocellulases as biorefining tools and open up new avenues for exploring their use in other biotechnological applications.

Preparation of interwoven structure composite paper via polylactic acid infiltrating fiber network

AbstractCellulose is commonly acknowledged as a sustainable material owing to its abundance and renewability. However, the abundance of hydroxyl groups makes the paper material highly hydrophilic, and the hydrogen bonds between the fibers are easily broken by water, leading to the degradation of mechanical properties. This work details the fabrication of a composite paper comprising interwoven cellulose and polylactic acid (PLA) structures through hot‐pressing and PLA impregnation onto handwritten paper derived from conventional wood pulp fibers as the substrate. The investigation assessed how varying PLA concentrations influenced the overall characteristics of the composite paper, including its morphology, structure, mechanical properties, water absorption behavior, and water contact angle. Experimental results revealed that the composite paper fabricated through our approach exhibited an intertwined structure comprising both PLA and cellulose. With a tensile index reaching 33.24 kN·m/kg and a mere 31.1% loss in tensile index post‐water treatment, the mechanical properties of the composite paper were significantly enhanced due to the robust interfacial compatibility between cellulose and PLA, as well as the adhesive effect of PLA. Furthermore, the composite paper (CP) is easily processable and amenable to thermoforming into paper trays as required, indicative of its potential applications in the packaging industry.

Halogen‐free boron‐based hybrid system for enhancing flame retardancy, mechanical and thermal properties of epoxy

AbstractThis study aims to increase the flame retardancy of epoxy‐based composites by using various flame retardants together with colemanite filler (CLM), which is a very mineral‐rich boron type. As a flame retardant, aluminum hydroxide (Al(OH)3) and boron‐containing compounds: borax (BRX) and natural minerals (tincal (TNC) and colemanite (CLM)), as well as barium metaborate (BaMB) synthesized by us were used. Scanning electron microscopy (SEM), x‐ray powder diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), contact angle (CA), and particle size analysis were used to characterize the composites and additives. All boron compounds increased the thermal stability of the composites. Except for the ER/CLM‐BaMB composite, other composites' surface contact angles were over 90°. In terms of both combustion and thermal properties, the best CLM‐BaMB‐Al(OH)3‐TNC ratio was determined as 15:5:15:15. The tensile strength, self‐extinguishing time, estimated and experimental Limited Oxygen Index (LOI) values for this composite were determined as 96 MPa, 65 s, 29.6%, and 25%, respectively. In addition, ANOVA was applied to determine the effect of hybrid filler type and different weight ratios on the mechanical properties of composites.

Utilization of rice straw for parallel production of sugars rich extract and paper

Abstract Complete utilization of different agricultural wastes is a great challenge before human society. The present study reports the valorization of rice straw for simultaneous production of reducing sugars and paper. The rice straw was first pre-extracted with water under different reaction conditions sequentially followed by papermaking. A maximum total reducing sugars (TRS) upto 12.38 % was extracted through aqueous pre-treatment. The pulped biomass was assessed for paper properties viz., tensile index, tear index, burst index, Kappa no. and brightness. For untreated rice straw tensile index, tear index and burst index were recorded within a range of 30.9–35.8 N m/g; 2.25–2.62 mN m2/g and 1.91–2.35 kN/g respectively where as it were ranged from 31.1 to 33.7 N m/g, 2.02–2.51 mN m2/g and 1.78–2.08 kN/g respectively for pretreated rice straw. Moreover, for untreated rice straw, kappa number and brightness were recorded in a range from 20.7 to 26.6 and 32.4 to 36.7 % ISO respectively, whereas for pre-treated rice straw it ranged from 19.1 to 26.3 and 31.6 to 35.5 % ISO respectively. High performance liquid chromatography (HPLC) analysis and field emission gun scanning electron microscopy (FESEM) were further employed during the study. In overall, extraction of underutilized sugars prior to pulping may prove as an efficient route for apt utilization of sugars followed by papermaking in near future.

Feasibility of lignin-containing cellulose nanofibrils derived from oil palm empty fruit bunch in enhancing the properties of non-wood handsheets

The addition of nanocellulose has been reported to improve the properties of handsheet, mainly the mechanical properties. Nevertheless, nanocellulose addition slows down the water drainage during handsheet making due to the filling effect and increase in fibre bonding, which results in the reduction of handsheet making productivity. In this research, the use of nanocellulose containing residual lignin was hypothesized to improve the productivity in comparison to pure nanocellulose. Lignin-containing cellulose nanofibrils (LCNF) samples having different lignin content were prepared from oil palm empty fruit bunch (OPEFB) through controlled multi-step bleaching process. The LCNF samples were then used in handsheet making with LCNF loading of 1, 2, 4, and 8 wt%. Three LCNF samples were successfully prepared (LCNF-1, LCNF-2 and LCNF-3) with different lignin content at 7.7%, 2.8%, and 0.5%, respectively. LCNF-2 and LCNF-3 had the average width of 31 nm, while LCNF-1 exhibited some portions of incomplete fibrillation which could be attributed to the presence of lignin. The addition of LCNF increased the drainage time compared to the one without LCNF (control), and the drainage time increased with the increase in LCNF loading. Overall results indicated that the addition of 4 wt% LCNF-2 contributed to the best combination in terms of drainage time, tensile index and tear index at 11.3 s, 38.1 Nm/g, and 9.3 mN.m2/g compared to the control sample (8 s, 31.8 Nm/g, and 7.4 mN.m2/g respectively). LCNF-3 gave comparable results, however from sustainability point of view, it is less favoured as it requires more bleaching chemicals to be produced. Findings from this research highlight the importance of lignin in improving the productivity and properties of nanocellulose-incorporated handsheet.

Fractionation of wood due to industrial chipping: effects and potential for Kraft pulping of European spruce.

The research conducted on kraft cooking of for different chip sizes is often not representative for the industrial process since the chip size fractions were made of high-quality wood without impurities. We evaluated the effects and the potential of cooking non ideal spruce chip fractions after industrial chipping and screening. The chips were classified according to SCAN 40:01, and the respective fractions were cooked under the identical conditions to mimic the effect of a joint cooking in the industrial digester. For the undersized chips we found higher bark content, a lower screened yield, a higher Kappa number, lower fiber length and lower tensile strength. For the oversized chips, the fiber length and tensile index were also considerably lower. A lower wood quality due to high knot content in the larger fractions was found to be the reason for that. Based on the data obtained from the experiments and literature, different process options for increased yield and reduced chemical consumption are discussed, e.g., separate cooking of different chip fractions. Improved chip screening seems to be the process improvement with lowest costs and highest impact.

Mechanical Properties of Fully Recycled Aggregate Concrete Reinforced with Steel Fiber and Polypropylene Fiber.

The study and utilization of fully recycled aggregate concrete (FRAC), in which coarse and fine aggregates are completely replaced by recycled aggregates, are of great significance in improving the recycling rate of construction waste, reducing the carbon emission of construction materials, and alleviating the ecological degradation problems currently faced. In this paper, investigations were carried out to study the effects of steel fiber (0.5%, 1.0%, and 1.5%) and polypropylene fiber (0.9 kg/m3, 1.2 kg/m3 and 1.5 kg/m3) on the properties of FRAC, including compressive strength, splitting tensile strength, the splitting tensile load-displacement curve, the tensile toughness index, flexural strength, the load-deflection curve, and the flexural toughness index. The results show that the compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced FRAC were remarkably enhanced compared with those of ordinary FRAC, and the maximum increase was 56.9%, 113.3%, and 217.0%, respectively. Overall, the enhancement effect of hybrid steel-polypropylene fiber is more significant than single-mixed fiber. Moreover, the enhancement of the crack resistance, tensile toughness, and flexural toughness obtained by adding steel fiber to the FRAC is more significant than that obtained by adding polypropylene fiber. Furthermore, adding polypropylene fiber alone and mixing it with steel fiber showed different FRAC splitting tensile and flexural properties.

Pulp and Paper Properties of Jenitri Wood (Elaeocarpus ganitrus)

Jenitri trees are widely distributed in community forests on Java Island and their wood is utilized for various products. The objective of the study was to assess the basic properties and quality of pulp and paper from jenitri wood. The tree was felled at the age of 5, and the base part was taken. Chips were processed using three different pulping methods in soda (17% NaOH), kraft (17% NaOH and 25% sulfidity), and neutral sulfite semi-chemical (NSSC) (12% Na2SO3 and 3% Na2CO3) processes. The fibers of jenitri had good derived values (slenderness, Runkel, and flexibility ratios) as well as chemical properties. The screened yields from the soda, kraft, and NSSC processes were 35.60 ± 4.75%, 35.05 ± 3.83%, and 46.29 ± 2.59%, respectively. The kappa numbers from the soda, kraft, and NSSC processes were 28.02 ± 7.35, 21.15 ± 1.61, and 71.28 ± 6.86, respectively. The handsheets had a burst index value of 0.65–2.94 kPa.m2/g, a tear index value of 5.23–5.47 mN.m2/g, a tensile index value of 15.13–30.49 Nm/g, a brightness value of 24.39–45.25%, and an opacity value of 98.83–99.68%. The soda pulp and the kraft pulp had slight differences in all parameters except for the Kappa number. The NSSC pulp showed slight differences in the selectivity of delignification ratio, tear index, and opacity, but produced a higher brightness level compared to chemical pulpings. The values of burst and tear indices for kraft pulp paper met the Indonesian National Standard for leaf bleached kraft pulp.

Enhancing capillary action of acidified paper to achieve uniform deacidification and long-lasting aging resistance

Deacidification is a necessary and urgent means of protecting acidified paper documents. However, the contradiction between deacidification efficiency and uniformity in existing aqueous or organic phase deacidification methods has not been resolved yet, which is mainly attributed to the differences in capillary action of paper on solvents with different polarities. In this work, a strategy of two-phase deacidification was proposed to achieve efficient and uniform deacidification and long-lasting aging resistance. Impregnation of nano magnesium oxide organic dispersion of deacidified paper achieved efficient batch deacidification and sufficient alkali reserve. Using ultrasonic atomization of saturated calcium hydroxide aqueous solution, the penetration of alkaline substances into paper promoted uniform deacidification based on strong capillary action. Meanwhile, microstructural reinforcement of paper fibers was achieved based on the multiple interactions. This method can endow the treated paper with better thermal stability and long-lasting aging resistance. After artificial accelerated aging for 30 d, the treated paper samples still maintained the highest tensile index (18.46 Nm/g), folding endurance (8.5 times), tear index (3.95 mN·m2/g) and displayed negligible chromatic aberration (∆E = 2.46 ± 0.21). This method greatly extends the lifespan of acidified paper, which has significant value for the protection of paper documents.

Sustainable utilization of pineapple fruit waste as a potential source of regenerated cellulose for the development of high-strength paper

Regenerated cellulose (RC) was prepared from pineapple crown waste fiber (PCWF) with a yield of about 45 %. The RC was blended with hardwood pulp (HP) to improve the mechanical properties of the paper. The composite paper with improved tensile index from 16.87 ± 0.75 NN mm/g to 28.98 ± 1.2 NN mm/g and burst index from 0.974 ±0 .083 kkPaPa mm22/g to 1.827 ±0 .153 kkPaPa mm22/g was developed by blending 20 % RC with 80 % HP. It was calculated that the production of one tonne of RC generates about 130 m3 of wastewater and it can be recycled after treatment with electrocoagulation technique. After wastewater treatment, chemical oxygen demand (COD) was reduced 84.8 %, total suspended solid (TSS) by 95.6 %, total dissolved solids (TDS) by 30.4 %, and biochemical oxygen demand (BOD) by 95.8 %. Importantly, the recycling behavior by reusing/recycling the treated wastewater for the regeneration process was investigated and a yield of about 42 % of the RC was observed.

The Effect of Mechanical Pre-treatment of Reject Pulp as Raw Material for LOCC Mixture on Medium Paper Quality

Reject pulp is pulp that is stuck in the screen hole during the pulp screening process because it is larger than the screen hole and has shives (more than two fiber chains that are still bonded), as well as blackish brown knots. Reject pulp from the process will be stored in landfills resulting in accumulation which can pollute the environment if the amount continues to increase in line with the production being carried out. Therefore, innovation is needed so that rejected pulp can be reprocessed. The current problem in the industry is reject pulp which has the effect of decreasing the value of paper properties and causing the surface of the paper to become rough. In this study, pre-treatment will be given for screen and material blending during beating. This study aims to determine the potential of reject pulp to be used as a mixture of LOCC raw materials on medium paper and the most optimum mechanical treatment to produce the best quality medium paper. The results in this study obtained the optimum value for the pre-treatment screen beating itself, namely a bursting factor of 27.70 g.m2/g.cm2, a tensile index value of 39.18 N.m/g, and a smoothness value of 9.425 Sec/10 ml. Meanwhile, the ring crush value obtained was the optimum value for the pre-treatment screen beating mix, which was 11.25 N.m/g. These results have met the standard properties of medium paper.

Synthesis of lignin-based polyurethane (LPU) and fabrication of degradable mulch film through LPU coating on cellulose paper

The use of non-degradable plastic mulch film causes significant environmental pollution and poses a threat to human and ecological safety. To address this issue, a viable solution is to develop bio-based and biodegradable paper mulch films to replace non-biodegradable ones in agricultural soils. In this study, a green and straightforward process was used to synthesize lignin-based polyurethane (LPU), which was then coated on cellulose paper (CP) of low basis weight of 30 g/m2 to fabricate a composite LPU/CP mulch film. An ultra-thin and lightweight LPU/CP mulch film was successfully fabricated with basis weight, thickness, and specific density of 40 g/m2, 80 µm, and 0.5 g/cm3, respectively. It was observed that surface coating was very effective in improving the physical strength of composite film as indicated by the improvement of tensile index from 19.3 N·m/g of CP to 65.0 N·m/g of LPU/CP mulch film. Moreover, LPU/CP mulch film presented excellent water resistance properties as suggested by the water contact angle of 107° and the water vapor transmission rate of 639.3 g/m2·day. LPU/CP mulch film also shows a balance between degradability and durability that it starts to break down into fractions after being buried for 28 days as a result of microbiological degradation. This work provides a feasible technology for fabricating eco-friendly, cost-effective, and biodegradable paper mulch film.

The Effect of Mechanical Recycling on the Thermal, Mechanical, and Chemical Properties of Poly (Butylene Adipate-Co-Terephthalate) (PBAT), Poly (Butylene Succinate) (PBS), Poly (Lactic Acid) (PLA), PBAT-PBS Blend and PBAT-TPS Biocomposite

Mechanical recycling of plastics is regarded as the best option to minimize plastic waste pollution in the environment as it is well established and offers valorisation of plastics; however, there is limited research on the mechanical recyclability of biopolymers. This work aimed to evaluate the effect of multiple reprocessing on the mechanical, thermal, physical, chemical, and morphological properties of poly (butylene adipate-co-terephthalate) (PBAT), poly (butylene succinate) (PBS), poly (lactic acid) (PLA), PBAT-PBS blend, and PBAT-thermoplastic starch (TPS) composite. Low-density polyethylene (LDPE), a conventional non-biodegradable plastic, was also reprocessed for comparison studies. The biopolymers were extruded seven times in a twin-screw extruder and injection moulded into test specimens. Their properties were investigated at each extrusion cycle. Tensile, impact strength, and melt flow index (MFI) results of neat PBAT and PBAT-TPS were stable with slight changes throughout the seven reprocessing cycles and were comparable to LDPE. The properties of PBS, PLA, and PBAT-PBS blend, on the other hand, started to decrease after the second melt extrusion cycle. In addition, differential scanning calorimetry (DSC), thermogravimetry (TGA), and dynamic mechanical analysis (DMA) results showed that LDPE, PBAT, and PBAT-TPS exhibited better thermal and mechanical stability as compared to PBS, PLA, and PBAT-PBS blend. The FTIR spectroscopy results showed that the characteristic peaks of C=O and C–O around 1710 cm−1 and 1046–1100 cm−1 for PBS, PLA, and PBAT-PBS decreased due to multiple thermal processing, while those of PBAT and PBAT-TPS were unaffected. Scanning electron microscopy (SEM) micrographs of the fractured cross-sectional surface of PBS, PLA, and PBAT-PBS tensile specimens clearly evidenced the degradation of the biopolymers by severely fractured morphology as a result multiple reprocessing cycle. The results demonstrate that the fully biodegradable PBAT and PBAT-TPS can be mechanically recycled for at least seven cycles, and therefore, the service life of biodegradable polymers can be extended, and it is comparable with petroleum-based plastic.Graphical

Direct utilization of cationic cellulose nanoparticles derived from maize-stalk parenchyma for intensifying mechanical properties and antibacterial activity in non-refined pulp paper

In recent years, an increasing focus has been placed on the mitigation of carbon dioxide emissions, underscoring the significance of the sustainable energy-conservation industry as a prominent and consequential field of development. As an energy-intensive procedure within the papermaking sector, the process of pulp-fiber beating necessitates an imperative exploration of alternative approaches aimed at mitigating energy consumption. This study has synthesized renewable cationic cellulose nanoparticles (CCNPs) extracted from the parenchymal cells of maize stalk pith. The objective is to demonstrate their viability as a reinforcing additive for paper sheets, thereby reducing the reliance on conventional beating processes. The results showed that CCNPs were prone to augment the physical strength of bleached papers, compared with unbleached papers. The inclusion of 9% CCNPs led to a remarkable 163.5% and 140.0% increase in tear and tensile indexes for bleached Eucalyptus paper, respectively. Incorporating CCNPs into non-refined paper yields physical traits akin to wood pulp paper beaten over 40 °SR. The CCNP-strengthened handsheets exhibited superior tensile and tear index in comparison to commercial dry strength additives such as cationic starch (CS) and cationic polyacrylamide (CPAM). Additionally, at 80 μg/ml concentration, E-B-9 displayed significant bactericidal effectiveness, achieving an impressive 97% reduction in Escherichia coli. This notable outcome is attributed to the presence of quaternary ammonium salt moieties in the formulation. This investigation introduces a promising approach where in the utilization of CCNP as an innovative multifunctional agent for paper holds the potential to enhance paper performance and concurrently reduce production costs.

Mechanical properties of twisted galvanized iron fiber reinforced concrete with different contents and pitches

Utilizing galvanized iron (GI) instead of expensive steel fiber has become a new technique in concrete construction to improve the mechanical properties of concrete. Tensile strength tests confirm that twisted GI fibers could serve as a viable alternative to steel fibers. Using deformed fiber instead of straight fiber increases the strength parameters of concrete significantly. As such, twisted GI fibers were employed in this study to improve the quality of the concrete. The GI fibers were mechanically twisted with varying twisting pitches (4, 6, and 8 turns per inch) to create rope-like fibers. Thirteen different concrete mixtures were prepared using three different fiber contents (1.0%, 1.5%, and 2.0% by weight), maintaining a constant 25.4 mm fiber length. Compressive strength, split tensile strength, flexural strength, toughness indices, and residual strength of GI fiber reinforced concrete (GIFRC) were determined. Employing GI fibers increased the compressive strength to a range from 13.4% to 28.9%, the split tensile strength from 18.8% to 42.5%, and the flexural strength from 11.5% to 46.0% compared to the control specimen. Besides, twisted GI fiber increased compressive strength from 1% to 7%, split tensile strength from 2% to 11%, and flexural strength from 3% to 13% than those of plain GIFRC. Toughness indices and residual strengths were significantly higher for GIFRC beams compared to the control specimen, which indicated greater energy absorption capacity of GIFRC. Additionally, strength prediction models were established to estimate different strength parameters with varying twisting pitch of GIFRC. Experimental results resembled the proposed strength models. Therefore, using twisted GI fibers in concrete can be an excellent choice to improve the mechanical properties of concrete.

Enhancing Paper Packaging's Wet Strength Using the Synergy between Chitosan and Nanofibrillated Cellulose Additives.

The demand for eco-friendly packaging materials has urged researchers to look for alternatives to petroleum-based polymers. In this regard, paper-based products have turned out to be a promising choice; however, their weak resistance to water has limited their application. The use of various additives to enhance paper's moisture resistance is a common practice. However, considering the growing global agenda for sustainable development, the search for new bio-based paper additives has become increasingly important. This study investigated the potential synergistic impact of the addition of nanofibrillated cellulose (NFC) and chitosan additives (CHIT) to different fiber combinations to improve paper's properties, in particular, their wet strength. The efficacy of the additive application order was examined and was found to be crucial in achieving the desired outcomes. The results showed that incorporating CHIT after NFC enhanced the paper's tensile and burst indicators, as well as the paper stretch in the dry state, by 35-70%, 35-55%, and 20-35%, respectively. In addition, the tensile index and stretch in the wet state improved 9-13 times and 2.5-5.5 times over, respectively. The air permeability decreased 2.5-12 times over. These findings demonstrate that the sequential addition of the NFC and CHIT additives yield a greater enhancement of paper's properties than using each additive separately.

Potential use of nanofibrillated cellulose-loaded cationic starch solutions as coating formulation for recycled fluting papers

Effects of cellulose nanofibers (CNF) and cationic starch (CS) were evaluated as coating components relative to the physical and mechanical properties of fluting papersheets fabricated from recycled corrugated cardboard fibers. Fabricated fluting papers were subjected to size press applications by three different coating blends. Coating suspensions were prepared at various concentrations of CNF (0.5%, 1%, 2%, 3%, and 4%) and 4 wt% CS, and the same amounts of CS/CNF. The paper sheets were fabricated using size press machine as three-time repetitive applications, followed by one-time drying section, and compared to uncoated, CS-coated, and CNF-coated papers. The application of CNF suspensions increased tensile indices up to 11.7%. Moreover, CS/CNF suspensions resulted in a 67.2% increase in tensile index values. The coating of CS/CNF suspensions increased the burst index values by 163% at the CS+1%CNF concentration when compared to the control pulp. Surface application of prepared suspensions reduced the porosity of the samples under all conditions. The highest reduction in the air permeability was observed in the CS+4%CNF-coated samples as 91.5%. It can be concluded that the superficial applications of CNF on the physical and mechanical properties of recycled fluting paper was more effective in the presence of CS.

Lignocellulosic biomass pretreatment with a lignin stabilization strategy and valorization toward multipurpose fractionation

Lignocellulosic biomass has emerged as a promising alternative with sustainable advantages for the production of a wide range of renewable products and value-added chemicals. In this study, a pretreatment strategy that use a fully recyclable acid hydrotrope (p-TsOH aqueous solution) to extract lignin and employ glyoxylic acid (GA) to stabilize lignin was proposed for biomass valorization toward multipurpose fractionation. 83.0 % of lignin was dissolved out by p-TsOH hydrotrope (80 wt%) with GA addition to form GA-stabilized product at 80 o C for 15 min. The stabilized lignin was subsequently used as an additive in the preparation of lignin-based suncream. Notably, the incorporation of 4 wt% lignin nanospheres into an SPF15 sunscreen yielded a measured SPF of 59.94. Furthermore, the depolymerization of uncondensed lignin into aromatic monomers yielded a high lignin-oil yield of 84.2 %. Additionally, direct heating of the pretreatment liquor facilitated the conversion of monosaccharides into furfural, achieving a desired yield of 53.7 % without the addition of any acid catalyst. The pretreatment also enhanced the enzymatic hydrolysis of glucan, resulting in a saccharification yield of 98.4 %. Moreover, short-term ultrasonication of the pretreated substrate yielded pulp suitable for papermaking. Incorporating 15 wt% fibers into the produced paper sheets led to a 5.3 % increase in tear index and a 25.4 % increase in tensile index. This study presents a viable pretreatment strategy for the multipurpose fractionation of lignocellulosic biomass, offering potential avenues for biomass valorization.

Microcrystalline cellulose: an alternative to increase the resistance of kraft packaging with recycled fiber

The consumption of paper packaging is increasing. On the contrary, the planted areas of Pinus spp. are showing a trend tendency of imbalance between supply and demand. Therefore, many companies are prioritizing the use of recycled fiber (RF). However, its inclusion can influence the quality of the product. This study aimed to evaluate whether the combination of RF with microscale cellulose will enable the production of resistant paper. The first step involved producing bench-scale samples of Kraft paper (with different percentages of virgin and RF) and characterized it physically (grammage, moisture, Gurley porosity, Z-traction, SCT, and Mullen). The second stage involved replicating the first stage with the inclusion of microcrystalline cellulose (MCC) and the elimination of Pinus spp. (LF). All formulations were approved for the physical characterization tests, except for the porosity analysis and grammage for F5. In the first test (MCC=0%), there was a reduction in tensile, compression, and burst index of 13.2, 7.3, and 19.5%, respectively, showing that the higher the percentage of RF, the lower the paper’s strength. In the second test for Formulation 3 (MCC=6%), there was an increase in the tensile, compression, and burst index of 9.5, 2.6, and 2.7%, respectively, when compared with Formulation 2 (LF=MCC=0%). This study demonstrates that the addition of up to 6% MCC strengthens the RFs and decreases the dependence on Pinus spp., making it a promising alternative for the production of sustainable and resistant packaging.