Molecularly Engineered Lignin-Derived Additives Enable Fire-Retardant, UV-Shielding, and Mechanically Strong Polylactide Biocomposites

Bio-based melamine formaldehyde resins for flame-retardant polyurethane foams

The polyurethane (PU) foams can be functionally tailored by modifying the formulation with different additives. One such additive is melamine (MA) formaldehyde resin for improving their flame-retardant properties. In this work, the glycerol-modified (GMF), sodium alginate (SGMF)- and lignosulfonate-modified melamine formaldehyde (LGMF) were prepared and used as flame retardants reacting with isocyanate to prepare the corresponding rigid polyurethane foams (GMF-PU, SGMF-PU and LGMF-PU). The thermomechanical properties and flame-retardant properties of the foams were characterized. The results showed that the specific compression strength of GMF-PU, SGMF-PU and LGMF-PU increased substantially compared to the foams from physical addition of MA, sodium alginate and lignosulfonate, all of which were greater than that of the foam without any flame retardant (PPU). Meanwhile, the cell wall of the foam pores became thicker and the closed pore ratio increased. The sodium alginate and lignosulfonate played a key role in enhancing foam thermal stability. The limiting oxygen index values and cone calorimetry results indicated the flame-retardant efficiency of GMF-PU, SGMF-PU and LGMF-PU was significantly enhanced relative to PPU. Meanwhile, the heat and smoke release results indicated sodium alginate and lignosulfonate could reduce the amount of smoke generation to different degrees during the combustion of the foam.

Mussel-inspired polydopamine modified mica with enhanced mechanical strength and thermal performance of poly(lactic acid) coating

Polylactic acid (PLA), as a green functional polymer, has been useful in various coating applications. However, due to the low mechanical strength and thermal stability of PLA, it needs to be improved in order to expand its application areas. In this work, a series of polylactic acid (PLA) nanocomposite films were prepared through introducing polydopamine-modified mica (PDA@MICA) as a self-assemble nanofiller to enhance its mechanical and thermal properties. The results demonstrated that PLA/PDA@MICA shows excellent mechanical properties. Tensile tests showed that PLA/PDA@MICA exhibits a 58.3 % increase in tensile strength and a 16.8 % increase in Young's modulus compared to pure PLA. Meanwhile, thermal performance testing shown the introduction of PDA@MICA led to an increase in crystallinities (Xc = 24.78 %). And the thermal decomposition temperature of PLA/PDA@MICA film (374 °C) was slightly higher than that of PLA film (367 °C). The simultaneous improvement of the mechanical and thermal properties was attributed to the formation of hydrogen bonds between PLA and PDA@MICA. In addition, the parallel arrangement of PDA@MICA and PLA macromolecular chains forms a unique "brick and mortar" structure in the coating, which enhances the mechanical properties of PLA/PDA@MICA composite coatings. This study reports a successful approach to simultaneously address the drawbacks of PLA, specifically its low thermal stability and mechanical strength, thereby promoting its widespread application in the coatings industry.

Exploiting Waste towards More Sustainable Flame-Retardant Solutions for Polymers: A Review

The development of sustainable flame retardants is gaining momentum due to their enhanced safety attributes and environmental compatibility. One effective strategy is to use waste materials as a primary source of chemical components, which can help mitigate environmental issues associated with traditional flame retardants. This paper reviews recent research in flame retardancy for waste flame retardants, categorizing them based on waste types like industrial, food, and plant waste. The paper focuses on recent advancements in this area, focusing on their impact on the thermal stability, flame retardancy, smoke suppression, and mechanical properties of polymeric materials. The study also provides a summary of functionalization methodologies used and key factors involved in modifying polymer systems. Finally, their major challenges and prospects for the future are identified.

Synthesis of a reactive lignin-based flame retardant and its application in phenolic foam

To improve the flame retardancy of phenolic foam from the perspective of sustainable development, it is a feasible way to add bio-based flame retardants into phenolic foam. Lignin has a similar structure to phenol, which provides a possibility to replace part of phenol. In this paper, we prepared a kind of reactive bio-based flame retardant based on enzymatic hydrolyzed lignin, in which side chain was chemically grafted with phosphorus and nitrogen and benzene ring would participate in the phenolic condensation reaction. According to elemental analysis and ICP-OES data, the content of nitrogen and phosphorus in modified lignin (NP-L) increased to 2.95% and 3.55% respectively. Compared with original lignin, the carbon residue rate of NP-L increased from 3.25% to 12.13% because of the presence of flame retardant elements N and P. Then lignin-based flame retardant was used to replace phenol for modifying phenolic foams (NPLPFX). The limited oxygen index (LOI) and compressive strength of phenolic foam were improved effectively by adding modified lignin when the substitution rate was less than 25%. The LOI and compressive strength of the modified phenolic foam with 5% replacement amount (NPLPF5) are 55.6% and 0.24 MPa, which increased by 88% and 60% compared with pure phenolic foam. The cone calorimetric data also showed that NPLPF5 had good flame retardancy, and the peak heat release rate and total heat release were significantly lower than PF. This work suggests a novel green strategy for improving the flame retardancy performance of phenolic foam and promoting the utilization of lignin.

Banana Peel Derived Chitosan-Grafted Biocomposite for Recovery of NH4+ and PO43

Biomass-derived adsorbents afford accessible and inexpensive harvesting of nitrogen and phosphorus from wastewater sources. Human urine is widely accepted as a rich source of nitrogen and phosphorus. However, direct use of urine in agriculture is untenable because of its unpleasant smell, pathogen contamination, and pharmaceutical residues. In this work, we have grafted chitosan onto dried and crushed banana peel (DCBP) to generate the biocomposite DCBP/Ch. A combination of FTIR, TGA, XRD, FESEM, EDX, and NMR analyses were used to characterize DCBP/Ch and reveal condensation-aided covalent conjugation between O-H functionalities of DCBP and chitosan. The adsorption performance of DCBP/Ch toward NH4+ and PO43- is in sync with its attractive surface porosity, elevated crystallinity, and thermostability. The maximum adsorption capacity of DCBP/Ch toward NH4+/PO43- was estimated as 42.16/15.91 mg g-1 at an operating pH of 7/4, respectively, and ranks highly when compared to previously reported bioadsorbents. DCBP/Ch performs admirably when tested on artificial urine. While nitrogen and phosphorus harvesting from human urine using single techniques has been reported previously, this is the first report of a single adsorbent for recovery of NH4+ and PO43-. The environmental compatibility, ease of preparation, and economic viability of DCBP/Ch present it as an attractive candidate for deployment in waste channels.

In Situ-Generated Heat-Resistant Hydrogen-Bonded Organic Framework for Remarkably Improving Both Flame Retardancy and Mechanical Properties of Epoxy Composites

In this study, the heat-resistant hydrogen-bonded organic framework (HOF) material HOF-FJU-1 was synthesized via in situ generation and then used as flame retardants (FRs) to improve the flame retardancy of epoxy resin (EP). HOF-FJU-1 can maintain high crystallinity at 450 °C and thus function as a flame retardant in EP. The study found that HOF-FJU-1 facilitates the improvement of char formation in EP, thus inhibiting heat transfer and smoke release during combustion. For EP/HOF-FJU-1 composites, the in situ-generated HOF-FJU-1 can remarkably improve both the mechanical properties and the flame retardancy of EP. Furthermore, the in situ-generated HOF-FJU-1 has better fire safety than the ex situ-generated HOF-FJU-1 at the same filling content. Thermal degradation products and flame retardation mechanisms in the gas and condensed phases were further investigated. This work demonstrates that the in situ-generated HOF-FJU-1 is promising to be an excellent flame-retardant candidate.

Carbon Nitride Grafting Modification of Poly(lactic acid) to Maximize UV Protection and Mechanical Properties for Packaging Applications

Due to their biobased nature and biodegradability, poly(lactic acid) (PLA) rich blends are promising for processing in the packaging industry. However, pure PLA is brittle and UV transparent, which limits its application, so the exploration of nanocomposites with improved interfacial interactions and UV absorbing properties is worthwhile. We therefore developed and optimized synthesis routes for well-designed nanocomposites based on a PLA matrix and graphitic carbon nitride (g-C3N4; CN) nanofillers. To enhance the interfacial interaction with the PLA matrix, a silane-coupling agent (γ-methacryloxypropyl trimethoxysilane, KH570) is chemically grafted onto the CN surface after controlled oxidation with nitric acid and hydrogen peroxide. Interestingly, only 1 wt % of CNO-KH570, as synthesized under mild conditions, is needed to significantly improve the UV absorption, blocking even a large part of both UV-C, UV-B, and UV-A outperforming the UV absorption performance of PLA and, for instance, polyethylene terephthalate (PET). The low nanofiller loading of 1 wt % also results in a higher ductility with an increase in elongation at break (+73%), maintaining the tensile modulus. The results on a joint optimization of UV protection and mechanical properties are supported by a broad range of experimental characterizations, including FTIR, XRD, DSC, DSEM, FETEM, XPS, FTIR, TGA, and BET N2 adsorption-desorption analysis.

Rethinking the pathway to sustainable fire retardants

Flame retardants are currently used in a wide range of industry sectors for saving lives and property by mitigating fire hazards. The growing fire safety requirements for materials boost an escalating demand for consumption of fire retardants. This has significantly driven both the industry and scientific community to pursue sustainable fire retardants, but what makes a sustainable flame retardant? Here an overview of recent advances in sustainable flame retardants is offered, and their renewable raw materials, green synthesis and life cycle assessments are highlighted. A discussion on key challenges that hinder the innovation of fire retardants and design principles for creating truly sustainable yet cost-effective fire retardants are also presented. This short work is expected to help drive the development of sustainable, cost-effective fire retardants, and expedite the creation of a more sustainable and safer society.

Potential application of inorganic nano-materials in modulation of macrophage function: Possible application in bone tissue engineering

Nanomaterials indicate unique physicochemical properties for drug delivery in osteogenesis. Benefiting from high surface area grades, high volume ratio, ease of functionalization by biological targeting moieties, and small size empower nanomaterials to pass through biological barriers for efficient targeting. Inorganic nanomaterials for bone regeneration include inorganic synthetic polymers, ceramic nanoparticles, metallic nanoparticles, and magnetic nanoparticles. These nanoparticles can effectively modulate macrophage polarization and function, as one of the leading players in osteogenesis. Bone healing procedures in close cooperation with the immune system. Inflammation is one of the leading triggers of the bone fracture healing barrier. Macrophages commence anti-inflammatory signaling along with revascularization in the damaged site to promote the formation of a soft callus, bone mineralization, and bone remodeling. In this review, we will discuss the role of macrophages in bone hemostasis and regeneration. Furthermore, we will summarize the influence of the various inorganic nanoparticles on macrophage polarization and function in the benefit of osteogenesis.

Recent advances in flame retardant and mechanical properties of polylactic acid: A review

The large-scale application of ecofriendly polymeric materials has become a key focus of scientific research with the trend toward sustainable development. Mechanical properties and fire safety are two critical considerations of biopolymers for large-scale applications. Polylactic acid (PLA) is a flammable, melt-drop carrying, and strong but brittle polymer. Hence, it is essential to achieve both flame retardancy and mechanical enhancement to improve safety and broaden its application. This study reviews the recent research on the flame retardant functionalization and mechanical reinforcement of PLA. It classifies PLA according to the type of the flame retardant strategy employed, such as surface-modified fibers, modified nano/micro fillers, small-molecule and macromolecular flame retardants, flame retardants with fibers or polymers, and chain extension or crosslinking with other flame retardants. The functionalization strategies and main parameters of the modified PLA systems are summarized and analyzed. This study summarizes the latest advances in the fields of flame retardancy and mechanical reinforcement of PLA.

Flame-retardant poly(L-lactic acid) with enhanced UV protection and well-preserved mechanical properties by a furan-containing polyphosphoramide

Despite good biodegradability and mechanical strength, the intrinsic flammability of poly(L-lactic acid) (PLA) impede its practical application. Introducing phosphoramide is an effective method to enhance the flame retardancy of PLA. However, most of the reported phosphoramides derive from petroleum resources, and their addition tends to deteriorate the mechanical properties, especially toughness, of PLA. Herein, a bio-based, furan-containing polyphosphoramide (DFDP) with high flame-retardant efficiency was synthesized for PLA. Our study found that 2 wt% DFDP enabled PLA to pass a UL-94 V-0 rating, and 4 wt% DFDP increased the limiting oxygen index (LOI) to 30.8 %. DFDP effectively maintained the mechanical strength and toughness of PLA. The tensile strength of PLA with 2 wt% DFDP reached 59.9 MPa, and its elongation at break and impact strength were increased by 15.8 % and 34.3 %, respectively, relative to those of virgin PLA. The UV protection of PLA was significantly enhanced by introducing DFDP. Hence, this work provides a sustainable and comprehensive strategy for the creation of flame-retardant biomaterials with improved UV protection and well-preserved mechanical properties, which possess a broad prospect in industrial application.

Solvent-free synthesis of high-performance polyurethane elastomer based on low-molecular-weight alkali lignin

Using cheap and green lignin as a partial substitute for petroleum-based polyols is highly attractive for sustainable development of polyurethane elastomers (LPUes). However, the traditional synthesis process of LPUes inevitably uses toxic solvents that are difficult to remove or carcinogenic. Here, we reported a solvent-free synthesis method to prepare lignin-containing polyurethane elastomers (SF-LPUes) with high strength, high toughness and high elasticity. Most of the hydroxyl groups of lignin reacted with isocyanates to form a strong chemical cross-linking network, while the unreacted ones formed a dynamic hydrogen bond network with polyurethane matrix, contributing to the in-situ formation of lignin nanoparticles to build a nano-micro phase separation structure. Consequently, a dual-crosslinking network structure was formed and endowed SF-LPUes with excellent mechanical properties. Especially, the SF-LPUes prepared from low molecular alkali lignin possessed a tensile strength as high as 38.2 MPa, a maximum elongation at break of 1108 %, and an elastic recovery ratio of up to 98.7 %. Moreover, SF-LPUes showed impressing reprocessing performance and aging resistance. This work provides an industrial application prospect for the synthesis of lignin-containing polyurethane elastomers via a solvent-free synthesis process.

Synthesis of High-Molecular-Weight Bifunctional Additives with both Flame Retardant Properties and Antistatic Properties via ATRP

Polystyrene (PS) is widely used in our daily life, but it is flammable and produces a large number of toxic gases and high-temperature flue gases in the combustion process, which limit its application. Improving the flame retardancy of PS has become an urgent problem to be solved. In addition, in view of the disadvantage that small-molecule flame retardants can easily migrate from polymers during use, which leads to the gradual reduction of the flame retardant effect or even loss of flame retardant performance, and the outstanding advantages of ATRP technology in polymer structure design and function customization, we used ATRP technology to synthesize the high-molecular-weight bifunctional additive PFAA-DOPO-b-PDEAEMA, which has flame retardant properties and antistatic properties. The chemical structure and molecular weight of PFAA-DOPO-b-PDEAEMA were characterized by FTIR, ¹H NMR, GPC, and XPS. When the addition of PFAA-DOPO-b-PDEAEMA was 15 wt %, the limiting oxygen index (LOI) of polystyrene composites was 28.4%, which was 53.51% higher than that of pure polystyrene, the peak of the heat release rate (pHRR) was 37.61% lower than that of pure polystyrene, UL-94 reached V-0 grade, and the flame retardant index (FRI) was 2.98. In addition, when the PFAA-DOPO-b-PDEEMA content is 15 wt %, the surface resistivity and volume resistivity of polystyrene composites are 2 orders of magnitude lower than those of polystyrene. This research work provides a reference for the design of bifunctional and even multifunctional polymers.

Developing a cerium lactate antibacterial nucleating agent for multifunctional polylactic acid packaging film

With the rapid development of the packaging industry, people have high requirements for the functionality of packaging materials. As a representative biodegradable packaging material, polylactic acid (PLA) still has some problems. Multifunctional additives in PLA are an effective modification method. In this paper, cerium lactate (Ce-LA) was synthesized by a precipitation method and integrated into PLA to prepare a functional PLA composite. The results showed that Ce-LA not only significantly improved the crystallinity but also imparted antibacterial ability to PLA. When the concentration of Ce-LA was 0.9 %, the crystallinity of PLA reached 39.35 %, which was 77 % higher than that of pure PLA. When the addition of Ce-LA was 1.8 %, the antibacterial rates of PLA against Staphylococcus aureus and Escherichia coli reached 93 % and 85 %, respectively. This study provides a beneficial solution for the development of PLA packaging materials with high crystallinity and antibacterial properties.

Construction of carbon-based flame retardant composite with reinforced and toughened property and its application in polylactic acid

To simultaneously improve the flame retardancy, strength and toughness of polylactic acid (PLA) fibers, a composite flame retardant CNTs-H-C was prepared with carbon nanotubes (CNTs) as the core, hexachlorocyclotriphosphazene as linker, and chitosan grafted on the surface. The prepared CNTs-H-C was introduced into a PLA matrix to obtain CNTs-H-C/PLA composites and fibers via a melt-blending method. The morphology, structure, flame retardant properties and mechanical properties were thoroughly characterized, and the flame retardant mechanism was studied. Results showed that the prepared CNTs-H-C displayed a nanotube-like morphology with good compatibility and dispersion in the PLA matrix. After blending with PLA, CNTs-H-C/PLA composites exhibited outstanding flame retardancy with limiting oxygen index (LOI) increasing from 20.0% to 27.3%, UL94 rating reaching V-0. More importantly, the introduction of CNTs-H-C did not affect the spinnability of PLA. Compared with pure PLA fibers, the LOI of CNTs-H-C/PLA fibers with a CNTs-H-C content of 1.0 wt% increased by 32.5%, and meanwhile the breaking strength and elongation increased by 28.2% and 30.4%, respectively. Mechanism study revealed that CNTs-H-C/PLA possessed a typical condensed phase flame retardancy mechanism. In short, we have developed a CNT-based composite flame retardant with reinforced and toughened properties for the PLA matrix. The prepared CNTs-H-C showed great potential in polymer flame retardancy and mechanical enhancement.

A CNT-based flame retardant was synthesized and introduced into PLA to simultaneously improve the flame retardancy, strength and toughness of PLA.

Unsaturated polyester resin modified with a novel reactive flame retardant: effects on thermal stability and flammability

A new reactive flame retardant (DTA), containing phosphaphenanthrene and triazine-trione groups was synthesized and applied to improve the flame retardancy of unsaturated polyester resin. The thermal stability, flame retardancy and combustion behaviors of UP/DTA thermosets were detected by thermogravimeric analysis (TG), limited oxygen index (LOI), vertical burning (UL94) test and cone calorimeter test. According to the research results, the addition of DTA contributed to improving the flame retardancy of UP. After adding 20 wt% DTA, the LOI of UP composite increased from 19.0% of the neat UP to 26.6%, and UL94 rating reached V-0. In addition, compared with pure UP, the peak heat release rate (pk-HRR), average heat release rate (av-HRR) and total heat release rate (THR) of UP/DTA-20 thermosetting material decreased by 44.0, 26.2 and 29.5%, respectively. In the gaseous phase, DTA decomposed to generate nitrogen-containing fragments with diluting effect and phosphorus-containing free radicals with quenching effect to inhibit the combustion. In the condensed phase, phosphaphenanthrene group of DTA decomposed to generate phosphorus-based compounds, which promoted the carbonization of the UP matrix and cooperated with triazine-trione group to increase the char yield. Therefore, DTA plays an important role in flame retardancy in the gas and condensed phases.

A lignin-based epoxy/TiO2 hybrid nanoparticle for multifunctional bio-based epoxy with improved mechanical, UV absorption and antibacterial properties

Lignin, as a natural polymer material, has the advantages of green safety, renewable, and pollution-free. It has a wide application prospect in the field of thermosetting. However, it has been attractive but a huge challenge to design high performance and high added-value lignin-based epoxy resin. Herein, lignin-based epoxy (LEP) was synthesized from moso bamboo-derived lignin, and then lignin-based epoxy/titanium dioxide (LEP/TiO₂) hybrid nanoparticle was synthesized via liquid deposition method for modifying lignin-based epoxy resin to prepare multifunctional bio-based epoxy. The results show that the LEP/TiO₂ hybrid nanoparticle exhibits a stable topological surface shape and good dispersion and uniformity. By adding 10 wt% LEP/TiO₂ hybrid nanoparticles, the multifunctional bio-based epoxy exhibits good mechanical strength and toughness, and the tensile strength and fracture toughness reach 36 MPa and 1.26 MPa·m^1/2, respectively. In addition, the thermal stability, UV absorption and antibacterial properties of the multifunctional bio-based epoxy are further improved. This study provides a facile and efficient method for the preparation of high-performance multifunctional bio-based epoxy composite and a novel solution for the utilization of lignin.

PLLA/Graphene Nanocomposites Membranes with Improved Biocompatibility and Mechanical Properties

In this work, nanocomposite membranes based on graphene and polylactide were evaluated for mechanical properties and biocompatibility. Single-layer graphene (SLG), graphene nanosheets (GNS), and poly L-lactic acid (PLLA) were prepared through layer-by-layer deposition and homogeneous mixing. The results revealed that PLLA/SLG nanocomposites and PLLA/GNS nanocomposites could show enhanced mechanical properties and biocompatibility. The addition of a tiny amount of SLG significantly improved Young’s modulus and tensile strength of the PLLA matrix by 15.9% and 32.8% respectively, while the addition of the same mass ratio of GNS boosted the elongation at break of the PLLA matrix by 79.7%. These results were ascribed to the crystallinity and interfacial interaction differences resulting from graphene incorporation. Also, improved biocompatibility was observed with graphene incorporation. Such nanocomposites membranes showed a lot of potential as environment-friendly and biomedical materials.

Enzymatic synthesis of kraft lignin-acrylate copolymers using an alkaline tolerant laccase

Abstract

Softwood kraft lignin is a major bioresource relevant to the production of sustainable bio-based products. Continued challenges to lignin valorization, however, include poor solubility in organic solvents and in aqueous solutions at neutral pH. Herein, an alkaline tolerant laccase was used to graft acrylate functionalities onto softwood kraft lignin, which is expected to enhance the reactivity of lignin with isocyanate when producing bio-based polyurethanes. Proton nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and high-performance liquid chromatography were used to confirm successful grafting of the acrylate monomer onto lignin and verify the importance of including tert-butyl hydroperoxide as an initiator in the grafting reaction. Laccase-mediated grafting of softwood kraft lignin under alkaline conditions produced lignin products with approximately 30% higher hydroxyl value and higher reactivity toward isocyanate. The reported enzymatic and aqueous process presents an opportunity for the sustainable valorization of softwood kraft lignin.

Key points

• Softwood kraft lignin displayed high phenolic hydroxyl content, polydispersity index and average molecular weight

• Grafting hydroxyethyl acrylate (HEA) monomer onto kraft lignin by laccase was successful at 60 °C and alkaline conditions

• Lignin-HEA grafted copolymer showed an increase in total OH value and an increase in average molecular weight

Supplementary information

The online version contains supplementary material available at 10.1007/s00253-022-11916-z.

Facile preparation of oxygen-rich porous polymer microspheres from lignin-derived phenols for selective CO2 adsorption and iodine vapor capture

Lignin is a natural O-containing aromatic amorphous polymers from the residues of biorefinery and industrial papermaking, it can derive lots of aromatic phenol chemicals used as industrial raw materials by an efficient depolymerization, and then produce synthetic polymers. Here, we selected six aromatic units from the liquid products of lignin depolymerization, and tried to prepare diversified O-rich hyper-cross-linked polymers (HCPs) by one-pot Friedel-Crafts alkylation reaction for CO₂ and iodine vapor capture. HCP1, HCP2, and HCP3 microspheres possessed similar porous structure with Brunauer-Emmett-Teller (BET) surface areas (S_BET) of 14.1-20.6 m²/g and high O content (26.34-30.68 wt%), while HCP4, HCP5, and HCP6 were composed of many bulks with 3D networks structure, and showed larger S_BET of 15.4-246.9 m²/g and relatively low O content (18.48-26.38 wt%). The results indicated that the chemical position and quantities of substituent groups (methoxy and alkyl) into lignin-derived units had evident impact on their morphology and textural parameters. These HCPs exhibited considerable CO₂ uptake (64.1 mg/g) and selectivity (35.2) at 273 K， and high iodine vapor uptake (192.3 wt%). Moreover, the performance analysis implied that the S_BET and pore volume of these HCPs had not played the dominated roles in the CO₂ and I₂ adsorption, while their pore size distribution, O-functional groups, and electron density will be more important for the capture of the both. This study will offer a facile synthesis of O-rich polymer microsphere adsorbents based on the green and sustainable lignin.

Nanocomposites Materials of PLA Reinforced with Nanoclays Using a Masterbatch Technology: A Study of the Mechanical Performance and Its Sustainability

Packaging consumes around 40% of the total plastic production. One of the most important fields with high requirements is food packaging. Food packaging products have been commonly produced with petrol polymers, but due to environmental concerns, the market is being moved to biopolymers. Poly (lactic acid) (PLA) is the most promising biopolymer, as it is bio-based and biodegradable, and it is well established in the market. Nonetheless, its barrier properties need to be enhanced to be competitive with other polymers such as polyethylene terephthalate (PET). Nanoclays improve the barrier properties of polymeric materials if correct dispersion and exfoliation are obtained. Thus, it marks a milestone to obtain an appropriate dispersion. A predispersed methodology is proposed as a compounding process to improve the dispersion of these composites instead of common melt procedures. Afterwards, the effect of the polarity of the matrix was analyzing using polar and surface modified nanoclays with contents ranging from 2 to 8% w/w. The results showed the suitability of the predispersed and concentrated compound, technically named masterbatch, to obtain intercalated structures and the higher dispersion of polar nanoclays. Finally, the mechanical performance and sustainability of the prepared materials were simulated in a food tray, showing the best assessment of these materials and their lower fingerprint.