Cobb Value Research Articles

Study on the properties of ground film paper prepared from lactic acid-modified cellulose

Abstract Lactic acid impregnated ground film paper was prepared using the method of lactic acid impregnation of raw paper. The physical properties, chemical composition, crystallinity, thermal stability, surface morphology of the paper, barrier properties, and light transmittance of the lactic acid paper were investigated using FT-IR, XRD, TGA, SEM, water vapor blocking, oxygen blocking, mechanical properties testing, and optical property testing. Results showed that at room temperature (20 °C), when lactic acid concentration was 100 %, reaction time was 48 h, and 100 °C high temperature drying prepared lactic acid paper, it exhibited superior performance: dry strength of 2.83 IkN/m, wet strength of 0.36 kN/m, Cobb value of 4.50 g/m2, tear of 359.42 mN, water vapor barrier of 693.46 g m−2 24 h−1, and oxygen barrier of 933.43 cm3 m−2 24 h−1. Degradation rate reached 22.94 % after two weeks of soil landfill.

Waterborne cellulose acetate pickering emulsion generation mediated by cellulose nanocrystals for paper coating applications

There is a continually increasing demand for alternatives to single-use, non-degradable, and synthetic plastic packaging. Environmentally friendly paper products offer a potential solution, but typically do not meet stringent demands for barrier and other physical property performance unless coated with polymeric films, usually polyolefins. Replacing conventional plastic film coatings with bio-based polymer alternatives, such as cellulose acetate, can provide competitive barrier property performance while also providing sustainability benefits. Furthermore, water can be used as a coating medium for added environmental and coatability advantages. In this study, 10 wt% Pickering emulsions of cellulose acetate dispersed in water and stabilized via cellulose nanocrystals (CNC) were generated. Rheological behavior, particle size, stability, and particle morphology were analyzed, as was the effect of modifying the CNCs using (2-Dodecen-1-yl)succinic anhydride over several weeks. Unbleached kraft paper was coated and compared to polyolefin coated and uncoated paper. Water vapor permeability, grease resistance, water absorption, and wet mechanical properties were all investigated, displaying promising properties for barrier paper coating. The grease kit test yielded a result of 10/12 for the coated paper versus 0/12 for uncoated, and water Cobb value showed a 60 % improvement. Lastly, the performance of the coated paper as a food takeout container coating was explored, with convincing results demonstrating a strong avenue of applicability. Overall, the waterborne cellulose acetate Pickering emulsion formation and its paper coating application yielded promising results for sustainable packaging development.

Preparation of double-effect water-proof and oil-proof paper based on carboxylated nanocellulose emulsified acrylate polymer

The materials utilized in paper packaging are derived from natural plant fibers, making them both environmentally friendly and biodegradable. However, traditional paper has been vulnerable to water and oil, which has limited its widespread use. In this research, a low-fluorine acrylate emulsion with a short carbon chain (CNF-C6FA) was created by employing carboxylated nanocellulose (TOCNF), dodecyl phenol ethoxylate, and sodium dodecyl sulfate as emulsifiers through semi-continuous seed emulsion polymerization. When combined with a specific amount of polyvinyl alcohol, this emulsion is applied to the paper surface to enhance the paper's hydrophobic and lipophobic properties. The findings revealed that paper coated with 5 g/m2 of CNF-C6FA achieved an oil-proof grade of 10 and a Cobb value of 13 g/m2, signifying a significant enhancement. It was discovered that TOCNF, acting as an emulsifier, not only maintained emulsion stability through steric hindrance, three-dimensional network structures, or vacancy effects but also conferred exceptional waterproof and oil-repellent properties to the paper. This can be attributed to TOCNF reinforcing the fluorocarbon groups in a directional arrangement, resulting in a dense and smooth coating layer on the paper's surface. The utilization of TOCNF as an emulsifier to produce environmentally friendly, waterproof, and oil-proof paper presents a promising approach for its high-value application.

Preparation of high‐barrier performance paper‐based materials from biomass‐based silicone‐modified acrylic polymer emulsion

AbstractHigh‐barrier performance, especially under extreme working conditions, is the key to replacing other types of packaging materials with paper‐based materials. In this paper, two biomass‐based polymers, sodium alginate (SA), and chitosan, were used to form a barrier coating with silicone emulsions to prepare a high‐performance paper‐based barrier material. By double coating, the water and oilproof functions were superimposed. The two prepared coated papers were characterized by infrared spectroscopy analysis, contact angle test, and scanning electron microscopy analysis, while their water resistance, oil resistance, thermal oil resistance, and thermal stability were tested. The water and oil repellency were achieved by double coating. The Cobb value of the chitosan‐silicone emulsion‐coated paper reached 5.3 g/m2, with a Kit grade of Level 12, and could block the penetration of castor oil at 80°C within 24 h. The Cobb value of the sodium alginate‐silicone emulsion‐coated paper was 41.6 g/m2, much higher than that of the uncoated paper, with a Kit grade of up to Level 10, which could slow down the rate of castor oil penetration at 80°C within 24 h. The test results showed that there was no chemical reaction between the paper‐based coatings, and the coated paper surface had good film formation, while the double coating method increased the thermal decomposition temperature of the overall barrier coating, effectively improving the thermal stability of the coating and achieving high‐barrier performance at lower cost and under extreme working conditions.Highlights Water and oil resistance under extreme operating conditions. High‐performance paper‐based barrier materials. Dual‐layer coating method for water and oil repellency. High‐barrier performance at lower cost. Excellent hot oil resistance and thermal stability.

Modification of polyvinyl alcohol with 2-hydroxypropionic acid and cross-linking with glutaraldehyde for the preparation of biodegradable mulch paper and its properties

Abstract The preparation of biodegradable mulch film with paper-based materials has become a significant focus in mulch film development due to the serious pollution caused by plastic mulch film. This study utilized the esterification cross-linking reaction of LA, PVA, and GA to coat the surface of paper as the substrate. FTIR, TGA, XRD, SEM, tensile testing, and oxygen, water vapor barrier performance tests were performed. The optimal conditions for film preparation were determined to be a 10 % PVA aqueous solution, 5 % GA content, and a PVA/LA/GA ratio of 1:2:1. The resulting film paper exhibited a dry strength of 6.52 kN/m, a wet strength of 0.23 kN/m, a tearing degree of 969.35 mN, a Cobb value of 12.04 g/m2, a water vapor transmission rate of 573.27 g m−2 24 h−1, and an oxygen transmission rate of 7.373 cm3 m−2 24 h−1. After a 6-week landfill degradation test, the film showed a degradation rate of 25.3 %, while still maintaining a tensile strength of 1.89 kN/m. Field application tests in greenhouses confirmed that the film paper facilitated the growth of strawberry, its mechanical and barrier properties suitable for a biodegradable paper mulch.

Rice straw-based sustainable food packaging material with improved strength and barrier properties: Development and characterization

Sustainable food packaging paper with high barrier and strength properties was developed with rice straw nanocellulose materials. Pulping and bleaching of rice straw were performed using an organosolv pulping and DED (D: chlorine dioxide bleaching; E: sodium hydroxide extraction) bleaching sequence. Bleached rice straw pulp was refined to 90°SR using a laboratory Valley beater. The laboratory handsheets were prepared using pulp slurry at 40°SR and 90°SR. The handsheets of cellulose nanofibrils (CNFs) made of highly refined pulp (90°SR) were surface sized using alkyl ketene dimer (AKD) wax to increase the barrier properties of paper for selective food packaging applications. The paper samples were tested for mechanical, optical, surface, and barrier properties, including tensile index, burst index, tearing index, bending stiffness, elongation, porosity, apparent density, opacity, Cobb value, water vapor transmission rate (WVTR), oil and grease resistance, and contact angle. The refined pulp (90°SR) was analyzed using field-emission scanning electron microscopy (FE-SEM), and it was observed that the morphology of the developed fibers changes to the nanoscale (<100 nm) for at least one dimension. The particle size distribution of the refined pulp using DLS analyzer also confirmed the cellulose fibers to near nanoscale. It was concluded that nanofibers were formed by a high degree of the mechanical pulp refining process and found to be much more economical than alternative processes in this direction. The sample handsheets of CNFs showed good strength and barrier properties. The barrier properties further increased when surface sizing was done using low-cost, nontoxic, and biodegradable AKD wax.

Study on the preparation of paper‐based barrier coatings with organosilicon modified acrylate lotion and its barrier mechanism

AbstractBased on the requirements of resource conservation and environmental development, an important factor for paper‐based materials to be able to completely replace plastic materials in the packaging field is their ability to achieve high‐barrier performance, especially thermal barrier performance under extreme working conditions. In this paper, we report the preparation of paper‐based high‐barrier materials utilizing silicone modified acrylate emulsions as coatings, followed by a comprehensive analysis of their application performance. The test results show that the Cobb value reaches 15.71 g/m2, the Kit grade reaches up to 10, and can slow down the penetration rate of castor oil at 80°C within 24 h. Based on our characterization results, we have constructed a microscopic model of paper‐based barrier material and analyzed the barrier mechanism of silicone emulsion coated paper from a molecular perspective. These findings offer valuable insights into the preparation of paper‐based barrier materials, providing process methods and application data.

Water and oil-grease barrier properties of PVA/CNF/MBP/AKD composite coating on paper

In this paper, three kinds of micro-nano bamboo powder (MBP) and alkyl ketene dimer (AKD) were added to the polyvinyl alcohol/cellulose nanofiber (PVA/CNF) coating to prepare PVA/CNF/MBP coated paper and PVA/CNF/M-MBP/AKD coated paper. The results showed that MBP improved the oleophobicity of PVA/CNF coating, and the grease resistance grade of PVA/CNF/B-MBP and PVA/CNF/M-MBP coated papers reached the highest level, with a kit number of 12. Among the PVA/CNF/MBP coated papers, the PVA/CNF/M-MBP coated paper has the best hydrophobic properties, with the water contact angle and Cobb value of 74° and 21.3 g/m2, respectively. In addition, when the AKD dosage was 0.2% in the PVA/CNF/M-MBP/AKD coating, the kit number of the coated paper was 11, the Cobb value was 15.2 g/m2, the water contact angle was 103°, and the tensile strength was found to increase slightly. Therefore, compared with PVA/CNF coated paper, PVA/CNF/M-MBP/AKD coated paper has good strength and excellent hydrophobic and oleophobic properties.

Evaluation of paper coated with cationic starch and carnauba wax mixtures regarding barrier properties

Studies of single-use packaging have aimed to replace materials obtained from non-renewable sources with biodegradable materials from renewable sources in response to environmental concerns. Their barrier properties maximize shelf life and product safety. To provide such green packaging, this work aimed to describe the chemical, physical, morphological, and barrier properties of bilayer coatings made from mixtures of cationic starch (S) and carnauba wax (W) on kraftliner paper (86 ± 1 g/m²). Two coating layers (15.0 ± 0.5 g/m²) of both materials in different proportions were compared to uncoated paper and doublewet-and-dry paper. The addition of cationic starch to carnauba wax raised the melting point of the wax, preventing it from completely entering the paper's pores but instead producing a layer on top of them. The hydroxyl groups present in coated paper S contributed to its hydrophilicity, showing a high Cobb value, absorbing 153 g/m² more water than control samples. Further, the mixtures showed higher hydrophobicity than the cationic starch-treated samples, with a high-water contact angle (100 ± 4°), similarly found for the W treatment. In addition, mixtures showed 0.35°/s less wettability than the W treatment. In terms of mechanical strength, the lower tensile strength and Young's modulus of the coated sheets brought on by hornification appear to have been predominantly caused by water in the suspensions. The addition of carnauba wax to the cationic starch decreased the resistance of coated papers to oil. However, there was an improvement in the water barrier by decreased water absorption and wettability and an increase in water contact angle.

Fabrication of recyclable high-barrier water- and oil-proof paper by sodium alginate/cellulose nanofiber/ethyl cellulose/ polyvinyl butyral

Paper-based packaging materials have seen explosive growth in recent years as consumers become more aware of the environmental and health hazards created by traditional food packaging materials. Even yet, there is a significant opportunity for improvement in the production of fluorine-free, water- and oil-proof, recyclable food packaging papers made from ecologically friendly polymers. In this study, we used sodium alginate (SA), cellulose nanofibers (CNF), ethyl cellulose (EC), and polyvinyl butyral (PVB) to create coatings that are impervious to water and oil. The paper was first impregnated with CaCl2 solution before SA and CNF were evenly mixed and applied to the paper. Ca2+ ion cross-linking strengthened the connection between the SA/CNF coating and the paper, which increased its oil-proof properties. The hydrogen bonding force in EC/PVB solution enhanced the water-proof performance and mechanical qualities of the paper. Finally, the water- and oil-proof paper showed excellent water repellency (Cobb value: 1.1 g/m2), oil repellency (kit rating: 12/12), low air permeability (0.2 µm/Pa·s), and stronger mechanical properties (4.21 kN/m). There is a great need for this fluorine-free, biodegradable, and recyclable paper-based material in the food packaging market due to its excellent barrier qualities.

A facile strategy to fabricate high-barrier, water- and oil-repellent paper with carboxymethyl cellulose/collagen fiber/modified polyvinyl alcohol

Due to the increasingly serious environmental and human health hazards brought by traditional food packaging materials, paper-based packaging materials have become increasingly popular among consumers in recent years. Currently, the fabrication of fluorine-free degradable water- and oil-repellent paper using low-cost bio-based polymers by a simple method is a hot subject in the field of food packaging. In this work, we used carboxymethyl cellulose (CMC), collagen fiber (CF), and modified polyvinyl alcohol (MPVA) to create coatings that were impervious to water and oil. The homogeneous mixture of CMC and CF generated electrostatic adsorption to impart excellent oil repellency to the paper. PVA was chemically modified by sodium tetraborate decahydrate, and the MPVA coating imparted excellent water-repellent properties to the paper. Finally, the water- and oil-proof paper showed excellent water repellency (Cobb value: 1.12 g/m2), oil repellency (kit rating: 12/12), low air permeability (0.3 μm/Pa·s), and stronger mechanical properties (4.19 kN/m). This non-fluorinated degradable water- and oil-repellent paper with high barrier properties prepared by a convenient method is expected to be in widespread use in the food packaging field.

Addition of bentonite to cationic starch matrix for coating on kraftliner paper to improve grease resistance

Abstract In this work, we aimed to analyze suspensions of cationic starch by adding 5 wt%, 7 wt%, and 10 wt% of bentonite as a bilayer coating on kraftliner paper (85 g/m2). The controls were doubly-wet-and-dry and uncoated kraftliner paper. In a coating machine, the formulations were applied until reaching a grammage of 15 g/m2 and then dried at 103 ± 2 °C. The test was carried out about pH, solids content, and viscosity of the suspensions. The physical characteristics of the coated papers were evaluated, as well as their ability to block water, water vapor, and oil/grease. We also analyzed with scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy. The packaging, having a water contact angle of up to 78° and 189 g/m² for Cobb, showed a low resistance to water, which is further responsible for decreased mechanical resistance. Nevertheless, the coating did not change the permeability to water vapor, however, bentonite promoted a decrease in wettability and Cobb value of the paper. The addition of 7 wt% bentonite to the cationic starch matrix promoted high oil resistance with 12 for kit-oil, while 10 wt% bentonite promoted greater pencil hardness, with a value of 8H. Bentonite strength and cationic starch showed good interaction, increasing oil resistance.

"EFFECTS OF DIFFERENT RATIOS OF STARCH-CONTAINING AKD ON PAPER PROPERTIES IN INTERNAL SIZING OF VARIOUS PULP TYPES "

The main objective of this study is to determine the effects of different ratios of starch-containing AKD emulsion in various pulp types sizing processes on paper properties. A secondary objective of the study is to evaluate the influences of starch content in AKD emulsion and AKD dosage applied to pulps. Three different pulp types were sized: unbleached kraft, bleached kraft and chemithermomechanical pulps. In preparation of AKD emulsions, three different ratios of starch were used. AKD was applied to all pulps under the same conditions at four different dosages based on oven-dried fiber weight. Test papers were produced and Cobb values (water absorptiveness), some mechanical and optical properties of the papers were determined. In addition, SEM, XRD and contact angle analyses were applied to papers produced with optimal sizing parameters. As a result of the study, it was found that the effects of AKD cause different behaviors depending on the pulp types. AKD was highly efficient in sizing chemithermomechanical pulp, decreasing the Cobb value by 90.9%. Depending on the pulp type, the starch content used in the emulsion preparation and the AKD dosage applied to the papers have various effects on the paper properties.

Lignin emulsifying rosin for improved sizing performance and mechanical properties of liquid packaging board

Global liquid packaging industry has been greatly spurred by the rapidly growing food & beverage industry all over the world. Liquid packaging board (LPB), as the main composition (75–80 %) of laminated liquid packaging cartons, must possess high-quality of hydrophobicity and physical properties for excellent leak-proof and protecting the packaged commodity. Herein, in this study, lignin is selected to prepare lignin cationic surfactant (LCS) by quaternary ammonium modification. Then cationic lignin modified rosin size ( L -CDRS) with uniform microsphere structure and high colloidal stability is successfully synthesized via a phase inversion process to improve the sizing performance and mechanical properties of LPB. The cation modified LCS presents improved amphipathicity of rich cationic charges and hydrophobic benzene ring skeleton, thus enhancing the electrostatic interactions between LCS and pulp fibers and improving the sizing performance of L -CDRS. The sizing performance of LPB is evaluated by varying the LCS dosages within L -CDRS and concluded that the edge penetration value and Cobb value of LPB handsheets exhibit an improved size performance with 2 % LCS within L -CDRS, implying the formation of homogeneous hydrophobic surface layer induced by the well-distribution of L -CDRS. In addition, the tensile index of LPB increased from 19.74 N·m/g to 25.96 N·m/g assisted by 2 % LCS emulsified L -CDRS, indicating an improved mechanical property. This study puts forward a practical and facile strategy to improve the sizing performance and mechanical properties facilitated by lignin enhanced rosin size and will further broaden the application range of traditional rosin size and lignin in LPB products. • Lignin was modified into quaternary ammonium etherified cationic surfactant with improved emulsifying ability. • Cationic lignin can emulsify rosin to prepare L -CDRS with uniform microsphere structure and high colloidal stability. • L -CDRS exhibited a significantly improved sizing performance of LPB compared with the control rosin size. • The addition of L -CDRS contributed greatly to the enhanced mechanical properties of LPB. • The mechanism of improved sizing performance and mechanical properties of LPB induced by L -CDRS size agent was proposed.

Water and oil-resistant paper materials based on sodium alginate/hydroxypropyl methylcellulose/polyvinyl butyral/nano-silica with biodegradable and high barrier properties

Despite many technical challenges in the development of safe and environmentally friendly food packaging paper materials with excellent water and oil resistance using simple methods, producing paper-based functional materials using bio-based polymers is currently an important topic in the food packaging industry. In this study, novel water and oil-resistant coatings for the paper were developed through the combination of sodium alginate (SA), hydroxypropyl methylcellulose (HPMC), polyvinyl butyral (PVB), and hydrophobic silica nanoparticles (HSNPs). To impart oil-repellency to paper, SA and HPMC were first mixed uniformly and coated on the base paper, which was pre-treated with calcium chloride solution. A compact and tough coating layer was formed on paper due to the hydrogen bonding between SA and HPMC molecules, and the crosslinking between SA and Ca2+ ions in the base paper. High water resistance of the paper was achieved through the coating of PVB and HSNPs on top of the coating of SA/HPMC. The final coated paper demonstrated outstanding oil resistance (kit rating: 12/12), water resistance (Cobb value: 4.23 g/m2), low water vapor transmission rate (100 g/m2·24 h), and improved mechanical properties. This fluorine-free, and biodegradable barrier paper will find excellent applications in the food packaging industry.

EFFECTS OF BUTYLAMINE TREATMENT ON CELLULOSE FIBERS DURING RECYCLING OF OLD CORRUGATED CONTAINERS (OCC)

This study aimed to determine the effects of butylamine treatment on cellulose fibers during the recycling processes. Three recycling stages have been carried out and two different butylamine (Ba) treatments (5.0% and 7.5%) were applied to old corrugated containers (OCC) papers during recycling. After each recycling process, papers were produced and the mechanical and optical properties of these papers were measured. SEM images and FTIR spectra were taken and the crystallinity index of the cellulose fiber was calculated by the XRD peak height method. Some improvement (11.0-15.2%) in paper brightness with the Ba treatment was realized in the third recycling stage, while yellowness values typically decreased by 1-2 points. Chemical treatments resulted in definite differences in water absorptiveness (Cobb value) for papers. The highest water absorptiveness of 160.0 g/m2 was observed with a 7.5% Ba treatment in the second recycling stage (75Ba2), indicating a value about 15.6% higher than that of the control. The highest tensile and burst indices were observed with 7.5% Ba treatment in the third recycling stage, indicating approx. 28.7% higher tensile and 34.5% burst indices, compared to the control at similar recycling stages. In contrast, the highest tear strengths of 4.54 Nm2/g, followed by 3.86 Nm2/g, were observed for untreated samples in the second and first recycling stage, respectively. The butylamine treatment in the recycling processes increased the cellulose crystallinity more (1.3%), compared to the control. It seems that the strength properties of recycled paper, such as tensile and burst, are closely related to the individual fiber strength and fiber bonding potential, which are typically reduced in recycling, but could be improved by Ba treatment.

Cellulose nanofibers/polyvinyl alcohol blends as an efficient coating to improve the hydrophobic and oleophobic properties of paper

The effect of cellulose nanofibers (CNFs)/polyvinyl alcohol (PVA) coating on the hydrophobic, oleophobic, and strength properties of paper were investigated. The results showed that the size of bamboo fibers (BFs) decreased significantly and the crystallinity increased significantly after biological enzyme treatment. The average length of CNFs obtained by high pressure homogenization was 2.4 µm, the diameter was 28.7 nm, and the crystallinity was 63.63%. When the coating weight of PVA/CNF was 2.0 g/m2 and the CNF dosage was increased from 0.0% to 3.0%, the paper grease resistance grade was increased from 7 to 9, the Cobb value was decreased from 22.68 ± 0.29 g/m2 to 18.37 ± 0.63 g/m2, the contact angle was increased from 67.82° to 93.56°, and the longitudinal and transverse tensile index were increased from 67.72 ± 0.21 N m/g and 37.63 ± 0.25 N m/g to 68.61 ± 0.55 N m/g and 40.71 ± 0.78 N m/g, respectively. When the CNF dosage was 3.0% and the coating weight of PVA/CNF was 4.0 g/m2, the grease resistance grade of the paper was 12, the Cobb value was 21.80 ± 0.39 g/m2, and the longitudinal and transverse tensile indices were 72.11 ± 0.43 N m/g and 42.58 ± 0.48 N m/g, respectively. In summary, the increase of CNFs can effectively improve the lipophobicity, hydrophobicity and tensile strength of the PVA coated paper.

QUALITY COMPARISON OF DUPLEX CARTON 350 GR/M2 BASED ON SNI-0123: 2008

Duplex cartons will be one type of carton that is widely used as a primary or second packaging. Duplex cartons have hygroscopic properties that can be salted on the physical and quality of the carton duplex. The value of this Final Task paper is the way of quality of cardboard in the field and the efforts of the process and who is in the field champion of The Indonesian National Standard (SNI 0123:2008). While the purpose of this writing is For those who know the process of creation of duplex carton quality 350 gr / m2, To understand the results of the creation of the quality of both duplex cartons from different companies, and For to dye the quality of cartons 350 gr / m2 in the market of different companies. Which method in writing this Final Task paper is the Task Related to Indonesian National Standards (SNI 0123:2008). Located from the creation and duparan quality of its own results, the two duplex cartons there are different qualities, for the production of PT X. Cobb value which is passionate and quality questions according to SNI 0123:2008 while for the production of PT Y. brightness value who can not be questioned sni 0123:2008. SNI 0123:2008 was prepared with the purpose of standardization, but the standard provisions were not met and not supervised in companies that do not apply sni standard 0123:2008, but in companies that apply sni standard 0123:2008 found also incompatible, therefore it is recommended to be carried out monitoring periodically.Keywords— Quality duplex carton, Duplex Carton, SNI 0123:2008

Pine needles lignocellulosic ethylene scavenging paper impregnated with nanozeolite for active packaging applications

The pines needle falls approximately 2–3 ha−1 year−1 on the forest floors resulting in a considerable amount of lignocellulosic biowaste. The present study aimed to develop pine needles based lignocellulosic active paper and investigate the effect of 5, 20, and 30% (v/w) nano zeolite addition on the physical, mechanical, and microstructural property of the papers. The developed papers were characterized by scanning electron microscope, transmission electron microscope, Fourier transform infrared spectrometer, and X-ray diffraction. As the zeolite concentration was increased from 5% to 30% in the paper, enhanced water permeability was seen from 5.18 ± 0.34 - 3.88 ± 0.33 g/cm2/day (PN/ZL 30% paper). The addition of 5% zeolite increased the tensile and burst strength from 19.53 ± 3.53 Nm/g and 3.63 ± 0.23 kg/cm2, respectively. The porosity was increased from 340 ± 20 to 1170 ± 60, and Cobb value increased from 338.3 ± 1.5- 406.7 ± 1.5 g/m2. The alterations in terms of surface microstructure in the paper with 20, 30% zeolite were noticed whereas XRD illustrated the high compatibility among the lignocellulosic network of pines and zeolite. The pine needle paper with 30% zeolite possessed remarkable ethylene scavenging properties (62%), opening a way to valorize pine needle waste for food packaging application.

Nanofibrillated cellulose as coating agent for food packaging paper

Nanofibrillated cellulose (NFC), a promising bio-based nanomaterial, has received much attention in the field of coating preparation due to its unique properties. Herein, NFC was prepared from microcrystalline cellulose (MCC) via high-pressure homogenization process and deliberately employed as coating agent to enhance the properties of paper coatings and coated paper. The results demonstrated that the obtained paper coatings exhibited strong NFC concentration dependence on rheological behavior and displayed decreased water retention value with the increased NFC addition. Meanwhile, NFC addition was found to lead to the reduced Cobb value, improved air resistance, and enhanced tensile strength of coated paper. Under an optimized NFC addition of 0.30–0.40%, the properties of coated paper generally reached the optimum state. Moreover, SEM observation further confirmed that NFC addition imparted a relatively uniform surface structure to coated paper. Hence, NFC could be defined as an effective coating agent for developing high-performance coated paper for food packaging applications.