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Packaging waste makes up more than 10% of the landfilled waste in the United States. While consumers often want to make environmentally friendly product choices, we find that their perceptions of the environmental friendliness of product packaging may systematically deviate from its objective environmental friendliness. Eight studies (N = 4,103) document the perceived environmental friendliness (PEF) bias whereby consumers judge plastic packaging with additional paper to be more environmentally friendly than identical plastic packaging without the paper. The PEF bias is driven by consumers' "paper = good, plastic = bad" beliefs and by proportional reasoning, wherein packaging with a greater paper-to-plastic proportion is judged as more environmentally friendly. We further show that the PEF bias impacts consumers' willingness to pay and product choice. Importantly, this bias can be mitigated by a "minimal packaging sticker" intervention, which increases the environmental friendliness perceptions of plastic-only packaging, rendering plastic-packaged products to be preferable to their plastic-plus-paper-packaged counterparts. This research contributes to the packaging literature in marketing and to research on sustainability while offering practical implications for managers and public policy officials. [ABSTRACT FROM AUTHOR]

Hemp hurd fiber, a low-value waste stream from the hemp industry, has potential downstream applications as an alternative to non-renewable plastics for single-use food service ware and packaging applications. Packaging paper substrates made from chemically pulped hemp hurd, mixed in varying ratios with bleached thermomechanical radiata pine pulp were developed and tested. Handsheets were characterized using several mechanical property tests including tensile strength, tearing resistance, burst strength, short-span compression, ring crush, together with Gurley air resistance, contact angle, and Cobb60 tests. Generally, addition of hemp hurd fibers significantly improved handsheet mechanical properties. Hot-pressing of the handsheets so as to approximate molded fiber thermoforming further enhanced their performance, with pure hemp hurd handsheets having the highest mechanical properties and barrier performance. A prototype was successfully thermoformed from hemp fiber, demonstrating overall feasibility of this fibre source for molded fibre objects. [ABSTRACT FROM AUTHOR]

Beeswax is a bio-sourced, renewable, and even edible material that stands as a convincing option to provide paper-based food packaging with moisture resistance. Nonetheless, the difficulty of dispersing it in water limits its applicability. This work uses oxidized, negatively charged cellulose nanofibers along with glycerol to stabilize beeswax-in-water emulsions above the melting point of the wax. The synergistic effects of nanocellulose and glycerol granted the stability of the dispersion even when it cooled down, but only if the concentration of nanofibers was high enough. This required concentration (0.6–0.9 wt%) depended on the degree of oxidation of the cellulose nanofibers. Rheological hindrance was essential to prevent the buoyancy of beeswax particles, while the presence of glycerol prevented excessive aggregation. The mixtures had yield stress and showed pseudoplastic behavior at a high enough shear rate, with their apparent viscosity being positively influenced by the surface charge density of the nanofibers. When applied to packaging paper, the nanocellulose-stabilized beeswax suspensions not only enhanced its barrier properties towards liquid water (reaching a contact angle of 96°) and water vapor (<100 g m−2 d−1), but also to grease (Kit rating: 5) and airflow (>1400 Gurley s). While falling short of polyethylene-coated paper, this overall improvement, attained using only one layer of a biobased coating suspension, should be understood as a step towards replacing synthetic waxes and plastic laminates. [ABSTRACT FROM AUTHOR]

Wood-based paper fibers are inherently biodegradable. In contact with moist soil and in compost, papermaking fibers are readily broken down by soil microbes. Resistance to biodegradation is needed, as paper is used for special applications such as mulching in agriculture and forestry, the coating of construction materials, and for packing and wrapping under conditions where packaging materials may be exposed to contact with moist soil or other type microbial active contamination. A preceding study showed that paper chemical crosslinking with glyoxal, citric acid (CA), or methylated 1,3-dimethylol-4,5-dihydroxyethylene urea (mDMDHEU) results in substantially improved paper wet strength and lower paper water absorbency. The present study examined the efficiency of chemical crosslinking treatments with CA and with mDMDHEU to decrease the biodegradation rate of laboratory paper sheets and a sack paper, both made of kraft fibers. The biodegradation was examined using a 48-h enzymatic degradation test and a 2-month soil burial test. The results indicate that chemical crosslinking is an effective non-biocidal method for making sulphate kraft paper more resistant to biodegradation. In some end-uses, improved resistance to biodegradation, along with improved paper wet performance, can enhance paper performance comparable to plastic films. [ABSTRACT FROM AUTHOR]

Paper has gained popularity as a packaging material due to its reduced environmental impact compared with non-degradable alternatives. However, its flammability poses safety risks, prompting research on enhancing its flame retardancy. This work introduces a diffusion-driven self-assembly strategy (DDSAS) to create a functional graphene oxide (GO) coating on various packaging papers. DDSAS involves infiltrating the paper's cellulose microfiber network with branched polyethyleneimine (b-PEI), which binds firmly to cellulose microfibers. Electrostatic interactions between GO and b-PEI then drive GO assembly into a densely stacked, layered structure on the paper surface. This GO structure provides a physical barrier against flames and generates incombustible gases (CO2, H2O, NO2, and NO) when heated, diluting the surrounding oxygen concentration and acting as a heat insulation layer. These factors increase the flame retardancy of treated papers ten-fold. Additionally, the gradual reduction of GO upon heating forms reduced graphene oxide (rGO) on the paper, significantly increasing its electrical conductivity. As a result, the flame-retardant papers not only prevent the fire from spreading but can also act as fire sensors by triggering an alarm signal at the early stages of contact with fire. In summary, this work offers a rational strategy for designing and manufacturing flame-retardant paper packaging materials. [ABSTRACT FROM AUTHOR]

The identification of sustainable materials as an alternative to plastic is fundamental for the protection of the environment and for the safeguard of marine ecosystems. The replacement of plastic with organic materials for fish storage might affect its shelf-life due to the high concentration of oxidizable fatty acids in fish flesh. This study investigated the effectiveness of two organic packaging materials, namely coconut fiber (Coc) and paper (Pap), as alternatives to the conventionally used polystyrene (Pol), on the shelf-life, hygienic parameters, and quality traits of anchovies refrigerated for one (T0), three (T1), or seven (T2) days. The hygienic quality of anchovies packaged in the organic Pap and Coc boxes was better than the traditional Pol, probably due to the higher porosity of the packaging, which allows a higher bacterial proliferation. Results of the T-BARS test showed a lower (p < 0.05) malondialdehyde concentration in fillets from the Pap group, which increased (p < 0.05) from the first to the seventh day of storage. The polyunsaturated fatty acids concentration did not differ between groups, but it decreased (p < 0.05) from T0 to T2. Coconut fiber and paper are worthy of further investigation since these packaging materials did not affect the shelf-life and fatty acid profile of anchovies during storage. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop bio-based adhesives that can be used for various packaging papers. In addition to commercial paper samples, papers produced from harmful plant species in Europe, such as Japanese Knotweed and Canadian Goldenrod, were used. In this research, methods were developed to produce bio-based adhesive solutions in combinations of tannic acid, chitosan, and shellac. The results showed that the viscosity and adhesive strength of the adhesives were best in solutions with added tannic acid and shellac. The tensile strength with adhesives of tannic acid and chitosan was 30% better than with commercial adhesives and 23% for combinations of shellac and chitosan. For paper from Japanese Knotweed and Canadian Goldenrod, the most durable adhesive was pure shellac. Because the surface morphology of the invasive plant papers was more open and had numerous pores compared to the commercial papers, the adhesives penetrated the paper structure and filled the voids. There was less adhesive on the surface and the commercial papers achieved better adhesive properties. As expected, the bio-based adhesives also showed an increase in peel strength and exhibited favorable thermal stability. In summary, these physical properties support the use of bio-based adhesives use in different packaging applications. [ABSTRACT FROM AUTHOR]

Paper is widely used as a packaging material because it is biodegradable and completely safe for the environment. The use of antimicrobials as a coating on paper can improve its mechanical, optical, physical and antimicrobial properties. Antimicrobial packaging suppresses the development of pathogenic microorganisms in order to ensure the safety of the product, extend the shelf life and protect the quality of the product. Giving antibacterial properties to papers and cardboards expands their use in different areas and for different purposes. Antibacterial paper prevents the entry and development of harmful microorganisms such as bacteria, fungi, mould. Antimicrobials that occur naturally in nature have a number of advantages, as they are considered to pose less risk to the consumer. One of the modern directions in research is the inclusion of different types of active substances in the packaging material, which can give it additional functions, such as elimination of oxygen, moisture, ethylene, ethanol emission, antimicrobial activity and others. The present work aims to obtain plant extracts, their characterization and their surface application on paper. Extracts of Bulgarian herbs St. John's wort, cumin, rosemary, thyme and basil were obtained and characterized and studied. Plant extracts are applied by spraying on the surface of various papers. The antimicrobial effect of treated papers on gram-positive and gram-negative bacteria was studied. The results of the analysis of the obtained papers show the possibility of using plant extracts containing biologically active ingredients for the production of papers with barrier properties. The use of plant extracts is a promising and innovative solution. [ABSTRACT FROM AUTHOR]

BACKGROUND: Deinking is an important part of paper recycling that involves the removal of ink particles from the paper fibres. This industrial process is important so that the fibres can be recirculated back into paper production, which enables better sustainability as fewer fresh fibres are needed. In this study, we examined five different alternative fibre materials from different agricultural residues and industrial processes for the pilot production of papers. Papers containing fibres from invasive plants (Japanese knotweed), dedicated crops (miscanthus, acacia), agricultural residues (tomato stems), and industrial waste (jute - fibres from coffee bags) were printed with water-based flexo inks and deinked with two separate processes (chemical and enzymes). Mechanical (break and tensile index, breaking length) and optical properties (ISO whiteness, brightness and CIE L*a*b* values) were measured and ink elimination IR700 and deinking efficiency was calculated for the two deinking processes. RESULTS: Enzymatic treatment improved the mechanical properties of deinked pulp in comparison with the classic chemical treatment. Mechanical strength for almost all papers increased slightly (breaking length up to 20% in tomato and jute), and the optical result (brightness) increased similarly for both processes due to the bleaching action of the colour-shaded samples, whereas the deinking efficiency showed mixed results between chemical- and enzyme-type deinking (with chemical achieving better elimination measured at 700 nm) in the typical range of ink elimination values (15-35%) for flexographic inks. This indicates further optimization of the deinking with enzymes is needed due to different alternative fibre compositions and variations of residues in the delignification processes. CONCLUSION: Using a combination of adjusted enzymatic treatment as a precursor for deinking of paper-based packaging materials sourced from alternative fibres showed promising results regarding mechanical properties, whereas the optical properties need to be improved with cellulase optimization or by using mixes of different enzymes. These kinds of paper materials printed with flexo inks were found to be successfully deinkable with the chemical ISO-based deinking protocol. [ABSTRACT FROM AUTHOR]

Transport of volatile organic compounds (VOCs) through porous media with active surfaces takes place in many important applications, such as in cellulose-based materials for packaging. Generally, it is a complex process that combines diffusion with sorption at any time. To date, the data needed to use and validate the mathematical models proposed in literature to describe the mentioned processes are scarce and have not been systematically compiled. As an extension of the model of Ramarao et al. (Dry Technol 21(10):2007–2056, 2003) for the water vapor transport through paper, we propose to describe the transport of VOCs by a nonlinear Fisher–Kolmogorov–Petrovsky–Piskunov equation coupled to a partial differential equation (PDE) for the sorption process. The proposed PDE system contains specific material parameters such as diffusion coefficients and adsorption rates as multiplication factors. Although these parameters are essential for solving the PDEs at a given time scale, not all of the required parameters can be directly deduced from experiments, particularly diffusion coefficients and sorption constants. Therefore, we propose to use experimental concentration data, obtained for the migration of dimethyl sulfoxide (DMSO) through a stack of paper sheets, to infer the sorption constant. These concentrations are considered as the outcome of a model prediction and are inserted into an inverse boundary problem. We employ Physics-Informed Neural Networks (PINNs) to find the underlying sorption constant of DMSO on paper from this inverse problem. We illustrate how to practically combine PINN-based calculations with experimental data to obtain trustworthy transport-related material parameters. Finally we verify the obtained parameter by solving the forward migration problem via PINNs and finite element methods on the relevant time scale and show the satisfactory correspondence between the simulation and experimental results. Article Highlights: A mathematical model to describe transport of polar volatile organics through paper is proposed. Based on experimental data, the deep learning method of physics-informed neural networks (PINNs) is used to solve the inverse problem of finding the sorption time constant. Solutions for the forward problem are obtained by the standard finite element method (FEM) and PINN methods. These solutions are compared with each other as well as with the experimental data to verify the model. [ABSTRACT FROM AUTHOR]

Featured Application: An improvement in adhesion (gluing) in the printing production process. In this study, the effect of air plasma on the surface properties of printed and coated cardboard was investigated. The material was activated by low-pressure cold plasma for 1, 10, 20, and 30 s. Wettability changes on the surface were examined by contact angle measurements using the sessile droplet technique. The differences in the surface free energy were calculated using the Lifshitz–van der Waals/acid–base and Contact Angle Hysteresis approaches. Optical profilometry was used for the surface roughness evaluation and an X-ray photoelectron spectroscopy analysis was performed to find changes in surface chemistry. Adhesive strength tests were carried out to estimate the adhesion changes after the material's modification. It was found that the water and formamide contact angles increased after the plasma treatment while the diiodomethane contact angle did not change. As a result of the modification, the surface free energy also increased significantly and the surface roughness increased. The pull-off tests confirmed the improvement in the material's surface properties. Moreover, it was demonstrated that the optimal effect can be obtained after just 10 s of the plasma process. [ABSTRACT FROM AUTHOR]

A lignin-based PU coating was prepared for paper-based green packaging. Two representative diisocyanate were used to prepare the coatings. Due to the rigid aromatic, the physical properties of the TDI system reached the maximum below the lignin content of 40%. The HDI that contains flexible aliphatic chains alleviated the brittleness of coating, and it showed physical advantages when the lignin content was more than 50%. Owing to the high lignin content, the coating presented enhanced thermal stability. After coated with the lignin-based PU coatings, the dry tensile strength of coated paper was improved by 126%. Amazingly, the wet strength was increased from 0.31 to 12.6 MPa with an improvement nearly 40 times. Based on the coordination of lignin, Ag+ was introduced into the PU matrix, which imparted the coating with excellent antibacterial ability. The colony forming units of E. coli and S. aureus were both less than 1. However, no inhibition halo was observed, which indicated that the Ag was firmly anchored on the coating and the antibacterial ability is only available when the bacterial contact the coating surface. The lignin-based PU coating with favorable sustainability and properties shows great potential in paper-based green packaging fields. The prepared PU coating with high lignin content and firmly anchored Ag+ exhibits outstanding physical properties, thermal stability, and antibacterial property, which makes it an ideal candidate to be used in paper-based green packaging. [Display omitted] [ABSTRACT FROM AUTHOR]

Nowadays, the dependence on synthetic plastic-based materials for the preservation and transport of different types of products is very high, leading to major environmental and human health concerns, which highlights the importance of investigating sustainable options. Paper is a widely used bio-based material for packaging however, the development of newer and straightforward approaches to produce paper-based materials with increased functionalities and performance is still highly desired. In this work, we report the use of a bio-based photopolymerizable coating formulation, composed of tung oil, and using Darocur 1173 as photoinitiator, to develop functional papers with hydrophobic and improved water barrier properties, without compromising other properties. Coated paper samples were prepared, using different irradiation times (0, 15, 30, 60, and 300 s), to study the effect of this parameter on the properties of the coated papers. The ensuing coated papers presented pick-up values between 6 and 7 g/m2. Their hydrophobicity was significantly improved as evidenced by the increase in the contact angle values from about 71° to 127° and the significant decrease in the water absorption, measured by the Cobb test, from 108 down to 17 g/m2, upon a curing time of only 15 s. Furthermore, with this time of curing, the optical (viz. whiteness, brightness, and opacity) and mechanical properties (viz. tensile and burst strength) of paper were not affected. These results highlight the great potential of tung oil photopolymerizable coating formulations as a simple and promising alternative for the fabrication of more sustainable and functional paper packaging materials. [Display omitted] • Photopolymerizable bio-based coating for paper-based packaging materials • The obtained coatings confer high hydrophobicity to paper. • Papers with improved air barrier and mechanical properties were obtained. • Optimized curing time (15 s) compatible with manufacturing constraints [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel dimer acid-based waterborne polyurethanes (DWPUs) were designed and prepared. • DWPUs were first used as multifunctional coatings for paper substrates. • Papers coated by DWPUs exhibited excellent water- and oil-resistances. • Alkyl and uniform membrane of DWPUs are critical to improve papers' properties. Paper derived from lignocellulose has great advantages over plastics as packaging material, nevertheless, the poor water- and oil-resistances of paper-derived products limited their application in high-end field. Herein, novel dimer acid-based waterborne polyurethanes (DWPUs) with different content of dimer acid-based polyester polyol (DG) were prepared and used as water- and oil-resistant coating for paper substrate. The effects of DG contents on water- and oil-resistances, mechanical properties and thermal stability of DWPUs coated papers were systematically investigated. When the content of DG reached up to 7 wt% (based on polyester glycol), the paper coated by DWPU exhibited 88.06% decrease in Cobb 60 value, 8.7 times increase in kit rating compared with uncoated paper. Meanwhile, DWPUs coated papers showed good mechanical properties and thermal stability. These improvements are attributed to the flexible long-alkyl chain, and six-ring structure of DWPUs as well as the continuous and homogeneous DWPU-derived membrane on the surface of paper. This study provides a new framework for the preparation of high quality, multifunctional, environmentally friendly water- and oil-resistant coatings for paper substrates. [ABSTRACT FROM AUTHOR]

Paper-based packaging generally has poor performances in the gas/oil barriers. This work reports a paper-based packaging material prepared via the modification of conventional papers with TEMPO-oxidized cellulose nanofibers (TOCN)/cationic guar gum (CGG) hydrogel film. Specifically, the hydrogel film modification was realized through a layer-by-layer deposition on paper. The hydrogel film modification significantly improved the mechanical and barrier properties of the paper. Specifically, the 4-layer hydrogel film modified paper showed a tensile strength of 34.03 MPa and a burst strength of 510 kPa, respectively. In contrast, the unmodified paper exhibited a tensile strength of 26.78 MPa and a bursting strength of 388 kPa. The packaging performance of this TOCN/CGG hydrogel film modified paper was demonstrated via the fresh mooncake packaging test. Such hydrogel film not only provided the oil resistance, but also maintained the mooncake's freshness. This material can serve as a green and sustainable food packaging. [Display omitted] • A TOCN/CGG self-assembled hydrogel film modified paper reported • A 27% increase in tensile strength with the 4-layer hydrogel film modification • A kit number of 11 with the 4-layer hydrogel film modification • Freshness retention of mooncakes observed as packaged with modified paper [ABSTRACT FROM AUTHOR]

• Multidisciplinary evaluation of three novel perennial crops as feedstock for the pulp and paper industry. • Meadow hay blends generated higher tensile indices compared to the pure birch control. • Fibre lengths of 0.5 (meadow hay), 1.3 (Virginia mallow), and 0.9 mm (cup plant) were measured. • The fibre widths of cup plant and Virginia mallow are broader compared to hardwoods. • These promising raw materials will be valueable in cardboard production for sustainable packaging. While the demand for paper and packaging material is increasing, industry and consumers are searching for more sustainable raw materials. This study evaluates three non-wood perennials to find alternative raw materials for the paper and pulp industry. Meadow hay, cup plant (Silphium perfoliatum L.) and Virginia mallow (Sida hermaphrodita (L.) Rusby) are attracting attention as potential raw materials for the bioeconomy due to biodiversity benefits, low fertilizer requirements as well as high yields. For the first time a detailed view on their fibre morphology and use as paper feedstock is given. After three different mechanical grinding methods, the plant material was screened, pulped in NaOH and beaten in a PFI mill. Birch fibre has been chosen as short-fibre control and blend base. Hand-sheets with different pulp blends of birch and one of the three raw materials were made, and paper properties were measured. For meadow hay, Virginia mallow and cup plant fibre lengths of 0.5, 1.3, and 0.9 mm were measured. Therefore, all perennial plant materials have comparable fibre lengths to hardwoods. Meadow hay blends with birch pulp percentages of 50 % and 75 % generated higher paper strength compared to the pure birch paper at a beating intensity of 5000 revolutions (PFI). The paper strength of cup plant and Virginia mallow blends is comparable to the strength of the birch control. Due to these promising results, all analyzed raw materials could find their application, especially in the growing area of sustainable packaging materials. [ABSTRACT FROM AUTHOR]