Bioplastics Research Articles

Preparation and characterisation of polyvinyl alcohol/glycerol blend thin films for sustainable flexibility

Petroleum-based polymers pose significant environmental challenges; this prompts researchers to seek alternatives for the same. The foremost solution to replace petroleum-based packaging lies in bio-based polymers that can degrade with water, soil, and the environment. The most common and economical bio-based polymer today is polyvinyl alcohol (PVA), however, it has certain limitations such as brittleness, hydrophilic nature, etc. The primary objective of this study is to enhance the flexibility, transparency, barrier properties, and thermal stability of PVA by incorporating glycerol as a plasticizer. In this regard, thin films were prepared by utilizing a solution-casting technique (blade coating) upon the addition of numerous concentrations of glycerol ranging from 1 to 5 wt%. Here two sets of thin films were prepared i.e., with glycerol (modified) and without glycerol (pure PVA). Results suggest exceptional mechanical flexibility and enhanced optical properties in terms of improved transmittance (>90%) upon incorporation of glycerol into PVA. The modified films also demonstrated a significant increase in their water barrier capabilities in comparison to pure PVA films. When the concentration of glycerol reached to 5 wt%, a substantial increase in biodegradability and flexibility was witnessed resulting in reduced brittleness. Thus, the mechanical properties of the modified thin films exceeded that of pure PVA counterparts. The prepared thin films unveil exciting possibilities to be used in diverse applications; such as food packaging, membranes, biodegradable materials, etc,. The extensive discussion is presented in the light of observed results.

Bio-based Building Blocks and Polymers Global Capacities, Production and Trends 2023–2028

Bio-based Building Blocks and Polymers Global Capacities, Production and Trends 2023–2028

Can bioplastics always offer a truly sustainable alternative to fossil-based plastics?

Bioplastics, comprised of bio-based and/or biodegradable polymers, have the potential to play a crucial role in the transition towards a sustainable circular economy. The use of biodegradable polymers not only leads to reduced greenhouse gas emissions but also might address the problem of plastic waste persisting in the environment, especially when removal is challenging. Nevertheless, biodegradable plastics should not be considered as substitutes for proper waste management practices, given that their biodegradability strongly depends on environmental conditions. Among the challenges hindering the sustainable implementation of bioplastics in the market, the development of effective downstream recycling routes is imperative, given the increasing production volumes of these materials. Here, we discuss about the most advisable end-of-life scenarios for bioplastics. Various recycling strategies, including mechanical, chemical or biological (both enzymatic and microbial) approaches, should be considered. Employing enzymes as biocatalysts emerges as a more selective and environmentally friendly alternative to chemical recycling, allowing the production of new bioplastics and added value and high-quality products. Other pending concerns for industrial implementation of bioplastics include misinformation among end users, the lack of a standardised bioplastic labelling, unclear life cycle assessment guidelines and the need for higher financial investments. Although further research and development efforts are essential to foster the sustainable and widespread application of bioplastics, significant strides have already been made in this direction.

Embracing Sustainability: The World of Bio-Based Polymers in a Mini Review.

The proliferation of polymer science and technology in recent decades has been remarkable, with synthetic polymers derived predominantly from petroleum-based sources dominating the market. However, concerns about their environmental impacts and the finite nature of fossil resources have sparked interest in sustainable alternatives. Bio-based polymers, derived from renewable sources such as plants and microbes, offer promise in addressing these challenges. This review provides an overview of bio-based polymers, discussing their production methods, properties, and potential applications. Specifically, it explores prominent examples including polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and polyhydroxy polyamides (PHPAs). Despite their current limited market share, the growing awareness of environmental issues and advancements in technology are driving increased demand for bio-based polymers, positioning them as essential components in the transition towards a more sustainable future.

Advancing Sustainable Solutions: Exploring United Atom Model for Efficient Molecular Dynamics Simulation of Poly-ethylene Vanillic (PEV) Polymer

The development of green polymers is a crucial long-term solution to address the problem of plastic waste. In particular, the bio-based polymer polyethylene vanillic (PEV) has garnered interest due to its comparable mechanical and thermal properties to polyethylene terephthalate (PET), a widely used single-use plastic. Molecular dynamics (MD) simulations are commonly employed to study the molecular structure and dynamic properties of materials, offering cost-effective applications. However, the accuracy of MD simulation results heavily relies on the chosen force field model. The all-atom (AA) force field, while providing insights into molecular interactions, demands significant computational resources, especially for large systems like polymers. This study aimed to employ the united atom (UA) model with revised OPLS-UA force field parameters for the biopolymer PEV, aiming to reduce computational time in dynamic and physical investigations. Consequently, the UA model successfully folded the PEV polymer in a manner resembling the single-chain PEV treated with the AA model, while also predicting a glass transition temperature (Tg) close to the experimental value of 348 K. These findings underscore the potential of the UA model for simulating PEV and its promising implications.

Biodegradable polymer films: processability, technological properties and their viability for flexible packaging applications

AbstractNowadays, there is a rising interest in the packaging industry regarding more environment‐friendly (i.e. biodegradable and/or compostable) polymer‐based solutions, especially for film blowing applications. However, replacing traditional, fossil resource‐based polymers typically used for such applications is not an easy task, since the more environment‐friendly solutions must have adequate features in terms of processability and final properties. In this work, three commercial biodegradable (and, at least partially, biobased) polymers were investigated by a preliminary rheological and mechanical analysis, in order to perform film manufacturing experiments in laboratory equipment. Furthermore, oxygen and water vapour barrier properties were studied by permeability measurements. The investigation was ultimately performed on films produced in industrial equipment, and the results were compared to those for a typical, standard polypropylene (PP) film used in flexible packaging applications. It was found that the mechanical properties were adequate (in some cases, even up to 25–30% higher than for the PP counterpart), as well as oxygen permeability. On the other hand, water permeability was significantly higher than that of PP films, and this should be taken into account in cases where high water vapour barrier properties are required. © 2024 Society of Industrial Chemistry.

Fast-curing bio-based thermoset foams produced via the Michael 1,4-addition using fatty acid-based acetoacetate and acrylate

This study introduces an approach for creating bio-based polymer foams exploiting the Michael reaction that could be utilized as thermal insulation. The thermoset foams were developed using a second-generation bio-based feedstock – tall oil. Tall oil is a by-product of wood pulping in paper manufacturing and mainly comprises unsaturated fatty acids like oleic and linoleic acid. The study explores the use of tall oil-based acetoacetates (Michael donor) combined with various acrylates (Michael acceptor), petrochemical-based (bisphenol-A ethoxylate diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate), and bio-based (epoxidized soybean oil acrylate, epoxidized tall oil free fatty acids-based acrylate), to develop polymer foams that meet today's sustainability requirements. The developed polymer foams underwent extensive characterization. Matrix curing parameters were assessed by measuring changes in dielectric polarization during curing. Foaming parameters, including start and rise times, were precisely measured. The chemical composition of the foams was analysed using Fourier-transform infrared spectroscopy. Their thermal, thermo-mechanical, and mechanical properties were evaluated through thermal gravimetric analysis, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and compression tests. Additionally, the content of closed-cell and the coefficient of thermal conductivity were determined, further characterizing the foams as potential thermal insulation materials. Foams from bio-based donors with petrochemical-based acceptors exhibited a range of enhanced properties. They not only achieved high glass transition temperatures (up to 85 °C by DSC and up to 108 °C by DMA) but also displayed a spectrum of mechanical strengths (compression strength ranging from moderate to as high as ∼ 0.40 MPa) and good thermal isolation properties (thermal conductivity coefficient ∼ 31mW/(m·K)). Bio-based foams, derived from renewable resources, were characterized by properties fitting for flexible foam applications, such as low glass transition temperatures (down to −9.7 °C by DSC and down to 9.8 °C by DMA), reduced compression strength (approximately 0.011 MPa), and increased thermal conductivity (up to 46.7mW/(m·K)), indicating their potential utility in applications where flexibility is a key requirement.

In silico Characterization of Natural Blending Agents in Conjunction with Polyhydroxybutyrate (PHB) to Solicit Biopolymer film with Improved Thermal Stability

Polyhydroxybutyrate (PHB) is known to exhibit limitations in terms of thermal stability. Its susceptibility to thermal degradation, particularly when exposed to high temperatures, can hinder its performance in various applications. This study addresses the thermal stability limitations of Polyhydroxybutyrate (PHB) by exploring strategies to enhance its performance through blending with biodegradable polymers. Focusing on the PHB-pectin blend, computational simulations unveil a remarkable 346.92 K increase in the glass transition temperature (Tg), surpassing pure PHB. This elevation indicates strong intermolecular interactions, potentially involving hydrogen bonding, leading to a more rigid and thermally stable polymer system. The heightened Tg has practical implications for critical applications, such as automotive components and electronic devices, where resistance to elevated temperatures is essential. Emphasizing environmental benefits, the study highlights the use of biodegradable and bio-based polymers as eco-friendly alternatives to traditional plastics, contributing to reduced plastic waste. Overall, this research underscores the potential of thermally stable polymers to both enhance material performance and address environmental concerns across diverse industries.

Repeatable adhesion of bio-based polymer derived from tetrafunctional epoxides and polyhydric carboxylic acid

Bio-based network polymers were synthesized by cross-linking diastereomeric tetrafunctional epoxides, tetra-trans-LO (1) and tetra-cis-LO (2), with polyhydric carboxylic acid in the presence and absence of a catalyst. The cross-linking ability of 1 was higher than that of 2 and afforded to higher polymer yields, thermal stability, and mechanical strength. Repeatable adhesion with a moderately high recovery strength was achieved using 1 and polyhydric carboxylic acid in the presence of Zn(acac)2.

Developing biobased and degradable polyazomethines from hemin

The development of biobased polymers is emerging as a critical issue for researchers in this era, especially for conjugated or semiconducting polymers, due to the lack of natural conjugated building blocks. In addition, it is of urgent importance to develop degradable polymers to diminish the increasing amount of plastic waste. Therefore, we aim to utilize hemin-based materials as a building block to develop semi-conjugated, degradable, and biobased polymers in this study. Accordingly, hemin derived from bovine is modified to remove the ferric ion and functionalize with amine or aldehyde groups. The aldehyde-functionalized protoporphyrin is copolymerized with p-phenylenediamine, 2,7-fluorenediamine, and amine-functionalized protoporphyrin to form a series of polyazomethines of PDA, FDA, and PPIX. The semi-conjugated polyazomethines exhibit varied electrostatic potential distributions and frontier energy levels based on their compositions; in addition, all the polyazomethines present high biobased contents spanning the range of 60–80%. Notably, PPIX can be rapidly depolymerized by acid hydrolysis with 0.01 mol L−1 of HCl within several hours, guaranteed by the evolutions of optical absorption and size-exclusion chromatography, which show that the polyazomethines degrade to monomers to short-chain oligomers. In the aspect of the optoelectronic device application, the semi-conjugated characteristics of the hemin-based polyazomethines give rise to their high performance as a photoresponsive polymer electret in photonic transistor memory. By fine-tuning the molecular structure and energy levels, the developed polyazomethine of FDA achieves decent data discernibility and long-termed cyclic operation as a component of memory electronics, thereby rendering green electronics exceptionally economical and environmentally feasible.

Recent trends in the development of Polyhydroxyalkanoates (PHAs) based biocomposites by blending with different bio-based polymers

Recent trends in the development of Polyhydroxyalkanoates (PHAs) based biocomposites by blending with different bio-based polymers

Biobased Immiscible Polylactic Acid (PLA): Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Blends: Impact of Rheological and Non-isothermal Crystallization on the Bead Foaming Behavior

Nowadays, bead foams are of great interest due to their high lightweight potential. The processing of such foams strongly depends on the crystallization and rheological behavior of the polymers used. By blending polymers, these properties can be tailored to obtain beaded foams with low density, small cell size and high cell density. As a bio-based polymer, PLA is of great interest due to its renewable carbon source. PLA suffers from its low thermal and rheological properties, which can be compensated by using blends. The correlation between the PLA/PHBV ratio and the rheological as well as the crystallization behavior was investigated. The use of PHBV as a minor phase significantly changes the rheological properties and increases the crystallization behavior of PLA. These findings were applied to the foam extrusion process to obtain low density bead foams. Bead foams with densities below 100 kg/m3, mean cell sizes below 50 µm and cell densities of 1 × 107 cells/cm3 were obtained.

Synthesis of hydrophobic biopolyesters from depolymerized Pinus radiata bark suberin

Abstract The bark of Pinus radiata offers an underutilized source of high-value renewable chemicals such as extractable polyphenols and lipophilic compounds (waxes and suberin). Here, the depolymerization and extraction of suberin from P. radiata bark and its repolymerization to form novel polyesters are reported. Three different strategies were evaluated for repolymerization of the suberin monomers, with starting materials and products characterized using chemical and thermal analysis techniques. The inclusion of comonomer (1,12-dodecanediol) to provide stoichiometric balance improved the conversion, product yield, solubility and increased molecular weight. Enzymatic polymerization conditions gave the highest yield, while the highest molecular weight was achieved using titanium butoxide, demonstrating that polymerization conditions could be varied to target desired product properties. Products were hydrophobic, as shown by contact angles, ϴ ≥ 90° after 30 s. This work highlights opportunities for utilizing suberin to add value to a P. radiata bark biorefinery concept. Potential future applications include its use as a starting material for novel bio-based polymers that can serve as water-repellent surfaces and coatings, replacing established products derived from fossil resources.

Viscoelastic Response in Hydrous Polymers: The Role of Hydrogen Bonds and Microstructure.

Water responsive polymers represent a remarkable group of soft materials, acting as a laboratory for diverse water responsive physical phenomena and cutting-edge biology-electronics interfaces. We report on peculiarly distinctive viscoelastic behaviors of the biobased water responsive polymer cellulose 10-undecenoyl ester, while biobased regenerated cellulose displays stronger hydroplastic behaviors. We discovered a novel hydrous deformation mechanism involving the stretching of hydrogen bonds mediated by hydroxyl groups and water molecules, serving as a crucial factor in accommodating deformations. In parallel, the microstructure of cellulose 10-undecenoyl ester with unique coexisting nanoparticles and a continuous phase of entangled chains is mechanically resilient in the anhydrous state but enhances structural stiffness in the hydrous state. This variation arises from a different hydration level within the hydrous microstructure. Such a fundamental discovery offers valuable insights into the connection between the microscopic physical properties that can be influenced by water and the corresponding viscoelastic responses, extending its applicability to a wide range of hygroscopic materials.

Environmental Durability of Bio-Based and Synthetic Thermoplastic Composites in Large-Format Additive Manufacturing.

This research investigates the durability of large-format 3D-printed thermoplastic composite material systems under environmental exposure conditions of moisture and freeze-thaw. Durability was evaluated for two bio-based composite material systems, namely wood-fiber-reinforced semi-crystalline polylactic acid (WF/PLA) and wood-fiber-reinforced amorphous polylactic acid (WF/aPLA), and one conventionally used synthetic material system, namely short-carbon-fiber-reinforced acrylonitrile butadiene styrene (CF/ABS). The moisture absorption, coefficient of moisture expansion, and reduction of relevant mechanical properties-flexural strength and flexural modulus-after accelerated exposure were experimentally characterized. The results showed that the large-format 3D-printed parts made from bio-based thermoplastic polymer composites, compared to conventional polymer composites, were more susceptible to moisture and freeze-thaw exposure, with higher moisture absorption and greater reductions in mechanical properties.

A review on bio-based polymer polylactic acid potential on sustainable food packaging

A review on bio-based polymer polylactic acid potential on sustainable food packaging

Poly(hydroxyalkanoates): Emerging Biopolymers in Biomedical Fields and Packaging Industries for a Circular Economy

AbstractPoly(hydroxyalkanoates) (PHAs) are a class of sustainable, bio-based thermoplastic polymers with attractive physiochemical properties, including non-toxicity, biocompatibility, elastomeric behavior by design, and piezoelectric characteristics. In the ongoing effort to reduce plastics waste, PHAs can play a substantial role due to their inherent biodegradability free of microplastics, customizable properties, and versatile applications. This includes their tremendous potential in a broad range of biomedical applications. Biomass-based materials have recently gained great interest in the health sector, given the vast amount of interdisciplinary research in bioengineering and medicine. Implantable biomaterials should not elicit any negative response at the implantation site, which differentiates them from general-purpose polymers. PHAs do not induce any thrombosis or antigenic response even after being in contact with blood in the human body during long-term use. The biocompatibility of PHAs is also a key factor in the rapid growth and proliferation of tissues onto and within these materials when served as tissue engineering scaffolds. By application, the biomedical field was estimated to be the second-largest market share for PHAs, in terms of volume, in 2022. While PHA-based materials bring forth a broad range of opportunities, they also present challenges that have limited their widespread use and a greater market share. A better understanding of their physiochemical properties and biodegradation rates, production challenges, and the need for cost-effective strategies are some of the hurdles that need to be addressed. This review paper provides an overview of the commonly used PHA homopolymers and copolymers in biomedical fields and packaging industries. The introduction of the manuscript presents the concept of bioplastics and their environmental significance, highlighting the urgent need for alternatives to conventional fossil-based plastics. The next sections briefly cover the synthesis, properties, as well as homopolymer and copolymer formulations, followed by the application of PHA-based materials in the biomedical field. Current opportunities and challenges, together with some insight into the future gathered from the published studies, have been brought in the concluding section of this paper.

Polyhydroxybutyrate (PHB) bioplastic characterization from the isolate Pseudomonas stutzeri PSB1 synthesized using potato peel feedstock to combat solid waste management

The global fossil-based plastic industry is at a crucial point, requiring bio-based polymers. Polyhydroxybutyrate (PHB) is formed under nutritional stress conditions; however, efficient bacteria and cheap substrates are needed. This study found that potato peel, a cheap and abundant carbon source, can improve PHB production. PHB crotonic assay screened 11 Sudan Black B and Nile red positive isolates for PHB production. PSB1, a Pseudomonas stutzeri PSB1 (MN539619) yields 2.39 g/L maximal PHB. PHB generation from high-carbon agro-wastes using Pseudomonas stutzeri PSB1was 3.09 g/L for potato peel. Plackett-Burman and CCD, a statistical optimization method, increased PHB production. After optimizing all CCD variables, potato peel, Urea, and RPM were found to increase PHB production (6.1 g/L). The optimized parameters extracted 3.98 g/L of PHB from 6.36 g/L of dry biomass of Pseudomonas stutzeri PSB1. FT-IR, NMR, TGA, and DSC were used to characterize and compare the extracted PHB biopolymer to Sigma Aldrich PHB powder. Extracted PHB-bioplastic was tested for tensile strength and Elongation at break. Based on the above criteria, the recovered PHB biopolymer from Pseudomonas stutzeri PSB1 is a good alternative to agricultural mulch films and non-biodegradable plastics.

Sustainable ultra-strong polyesteramide elastomers with rapid degradation and high resilience

Degradable polymers typically require prolonged exposure to harsh conditions for degradation, but this extended duration and severe treatment often result in incomplete breakdown, leading to the formation of harmful microplastics that pose significant environmental pollution risks. In this work, degradable alternating polyamide hard segments and soft crystallizable segments were combined by amide groups to design thermoplastic bio-based polyesteramide elastomers (PEAEs) with customizable properties and rapid degradability. The hard segment of the polymer features an alternating arrangement of amide and ester bonds. This arrangement facilitates the formation of small molecule monomers when the ester bond is broken, preventing microplastic contamination that may arise from incomplete degradation of the hard segment. Additionally, the inclusion of side groups in the soft segment disrupts the crystallization, enhancing its susceptibility to solvent penetration and thereby accelerating the degradation rate. After step-cyclic tensile tests, additional physical cross-linking points were formed in PEAEs to enhance their mechanical strength and elasticity. Furthermore, PEAEs demonstrated outstanding processing capabilities, including compounding, extrusion, pelletization, and spinning. This innovative approach introduces fresh design concepts for the industrial application of bio-based degradable polymers, playing a pivotal role in advancing resource conservation and environmental protection.

Decentralized production concepts for bio-based polymers - implications for supply chains, costs, and the carbon footprint

This paper presents a multi-dimensional evaluation of decentralized production networks based on modular production plants. The main objective of this evaluation is to examine the effects of different degrees of decentralization in production networks of the chemical industry. Using the production of a biopolymer as an example, the study includes strategic supply chain planning by agent-based simulations, economic evaluation by calculation of net present values and environmental assessment by calculation of carbon footprints. By allowing for dynamic reconfiguration of the decentralized networks over time, it is shown that mobile, modular plant concepts are beneficial to reduce supply chain expenses. Transportation efforts resulting from strategic supply chain planning are reduced by 40 % with increasing degree of decentralization. The profitability of the decentralized networks is dominated by the costs for the production processes themselves as capital and operational expenditures allocate to >50 % of the total costs. Product prices of 3000 to 5500 €2020 per ton are necessary to reach profitability of the decentralized production networks. Regarding the environmental assessment, the carbon footprint of the supply chain accounts for <3 % of the total emissions, which are dominated by the provision of process heat that accounts for 46 to 68 % of the total emissions. Carbon footprint of the decentral production networks can be significantly reduced by a systematic electrification of 90 % of the process heat demand.