Bio-based Poly Research Articles

Bio-Based Polyurethane Composites with Adjustable Fluorescence and Ultraviolet Shielding for Anti-Counterfeiting and Ultraviolet Protection.

Polyurethane and its composites play an important role in innovative packing materials including anticounterfeiting and ultraviolet protection, however, they are mainly derived from petroleum resources that are not sustainable. In this study, a 100% biobased thermoplastic polyurethane (Bio-TPU) was synthesized using biobased poly(trimethylene ether) glycol, pentamethylene disocyanate, and 1,4-butanediol. Subsequently, biobased tannic acid (TA) was employed to prepare biobased composites. The structures and properties of Bio-TPU and its composites were systematically evaluated. The results showed that the Bio-TPU/TA composite films had excellent and controllable fluorescence and UV-shielding properties. The fluorescence colors of the Bio-TPU/TA composite films could be adjusted to blue, green, and yellow by varying the TA content and adding coupling agents. Moreover, the UV transmittance of the Bio-TPU/TA composites decreased from 79.25 to 5.43% below 400 nm with an increasing TA content, indicating an excellent ultraviolet-barrier performance. Consequently, biobased TPU/TA composite films can be utilized as innovative anticounterfeiting materials and UV-shielding protection films. This study is expected to facilitate sustainable development in the polyurethane industry and broaden the high-end applications of polyurethane such as fashion, electronics, food manufacturing, pharmaceuticals, and finance.

Regulated crystallization and piezoelectric properties of bio-based poly(L-lactic acid)/ diatomite composite fibers by electrospinning

Regulated crystallization and piezoelectric properties of bio-based poly(L-lactic acid)/ diatomite composite fibers by electrospinning

Synthesis and evaluation of bio-based Poly(oxime-urethane) with intrinsic antimicrobial properties

Intrinsic antimicrobial properties can give polyurethanes a wider range of applications. In this work, the bio-based chain extender, 2,5-diformylfuran dioxime (DFFD) possessing antimicrobial characteristic, is used to synthesize the intrinsically antimicrobial poly(oxime-urethane) (Dx-PU) with isophorone diisocyanate (IPDI) and poly(tetramethylene glycol) (PTMG-1000), and its properties are investigated. The results show that the tensile strength is 19.12 ± 0.49 MPa, the Young’s modulus of the poly(oxime-urethane) is 118.70 ± 11.40 MPa. The elongation at break and Shore A hardness were 292 ± 11 % and 93 ± 2, respectively. Additionally, the Dx-PU demonstrated a high thermal decomposition temperature of over 250 °C and a low glass transition temperature of the soft segments at approximately −60 °C. Meanwhile, research on Dx-PU coating has demonstrated that Dx-PU coating is 100 % antimicrobial against E. coli and S. aureus, and is suitable for use on a wide range of substrates, including glass, engineering plastics, metal and leather with excellent adhesion (ISO 0), pencil hardness (2H), impact resistance (0.5 m·kg) and flexibility (2 mm). The Dx-PU coating also has significant antibacterial performance in everyday environments. The outstanding flexibility, moderate Young’s modulus, high elongation at break, good thermal resistance, and excellent antimicrobial performance of Dx-PU make it highly suitable for applications on high-contact surfaces such as hospital walls, public sanitation facilities, countertops, and door handles. As a bio-based chain extender from renewable sources, DFFD offers new solutions for the synthesis of bio-based antimicrobial polyurethane and its coatings.

Mechanical properties, gas permeability and biodegradation mechanism of biobased poly(ester amide)s from 2,5-furandicarboxylic acid and amido diols for sustainable food packaging

The aim of this work was to evaluate the functional properties of a family of poly(ester amide)s (PEAs) for flexible food packaging applications. The polymers under study were previously synthesized via random copolymerization of furan 2,5-dicarboxylic acid (2,5-FDCA) with different amounts of 1,10-decanediol and an amido diol (AD 46). Poly(decamethylene furanoate) (PDF) and poly(ester amide) 46 (PEA 46) were the reference homopolymers. PEA copolymers were compression molded into films and subjected to WAXS, DSC, SEM analyses and water contact angle, mechanical, gas barrier tests. The results showed a remarkable improvement in the functional properties of PEAs compared to those of PDF, with a decrease up to about 50% of O2 and CO2 transmission rates, which were found to be comparable to those of commercial PET. The mechanical properties of PEAs were also improved in comparison with PDF because of the increased toughness and higher resistance to plastic deformation, paired with elongation at break up to 650%. In order to assess the effects of contact with food, the prepared films were treated with food simulants. Moreover, the films were stored in conditions of controlled temperature and humidity, chosen to replicate real scenarios of application involving aggressive environmental conditions. After contact with food simulant liquids, the materials became more rigid and less ductile, but their gas barrier properties remained superior to those of commercially widespread polyolefins. Finally, films were subjected to composting tests: the higher the amido diol content, the faster the degradation rate, which occurred via a mechanism of bulk hydrolysis, because of the higher hydrophilicity of amide groups. Overall, the results highlighted the potential of PEA copolymers for the production of biobased, sustainable, flexible food packaging.

Development of poly(butylene oxalate-co-furanoate) copolymers with enhanced sustainability and hydrolytic degradability

Polyoxalate, a novel intrinsically hydrolysable polyester, garners significant interest for its high cost-effectiveness and versatility. However, concerns persist regarding its durability in practical applications. This study integrates bio-based poly(butylene furanoate) (PBF), which possesses remarkable barrier performance, into the poly(butylene oxalate) (PBOx) framework to synthesize poly(butylene oxalate‑co‑furanoate) (PBOF) with tunable degradation rates. The influence of incorporating BF units on thermal, crystalline, mechanical, and barrier properties was systematically analyzed. Results demonstrated the addition of BF units dramatically improved the balance between degradation and physical properties. Laboratory degradation experiments indicated that PBOF possessed significant degradation effects. Among them, PBOF-41 (with 41 % molar furanoate) decreased in weight by 20 % in freshwater, 70 % in an enzyme solution, and 8 % in artificial seawater within 30 days. After 28 days of degradation in soil, the residual weight was reduced to 80 % of its initial weight. Theoretical calculations and experiments have clarified the enhancement of the Gibbs free energy and energy barrier of the hydrolysis reaction by the BF unit. In summary, PBOF copolyesters have excellent gas barrier performance, adjustable thermal properties, well-balanced mechanical properties, and degradability, making them highly promising for sustainable plastic products.

Catechol- and Phenolic Hydroxyl-Functionalized Partially Bio-Based (Co)poly(ether sulfone)s with Multifarious Applicability

A largely bio-based new bisphenol, namely, 4,4′-((3,4-dimethoxyphenyl)methylene)-bis(2-methoxyphenol) (DMBM) was synthesized by the reaction of veratraldehyde with guaiacol. DMBM and varying compositions of DMBM and bisphenol A were polycondensed with bis(4-fluorophenyl) sulfone to afford reasonably high molecular weight film-forming (co)poly(ether sulfone)s possessing built-in methoxyl groups. T10 and Tg values of (co)poly(ether sulfone)s were in the range 382–478 °C and 171–187 °C, respectively indicating their good thermal stability and the values decreased with increase in mol % incorporation of DMBM. The methoxyl groups present in (co)poly (ether sulfone)s were quantitatively de-blocked resulting in the formation of corresponding polymers possessing pendant catechol moieties and free phenolic hydroxyl groups. By virtue of the presence of these functional moieties, (co)poly(ether sulfone)s are amenable for post-polymerization modifications, and exhibited properties such as antimicrobial (23 mm against Staphylococcus aureus and 18 mm against Escherichia coli)), antioxidant (72 % scavenger of free radicals), adhesive (2.24 MPa lap shear strength) and usefulness as redox-active agent in zinc-ion batteries. These data underscore the promise of DMBM as a versatile monomer of wider utility for the synthesis of functional (co)poly(ether sulfone)s capable of expanding their applicability beyond the conventional ones.

High thermal resistance biobased copolyester from 2,5-Thiophenedicarboxylic acid with excellent gas barrier properties

Driven by sustainable development strategies, bio-based polyesters have received significant attention due to renewable bio-derived monomers and various unique properties. In this study, a series of high molecular weight bio-based poly(ethylene-co-2,2,4,4-tetramethyl-1,3-cyclobutylene thiophenedicarboxylate) (PETTh) copolyesters on the basis of an emerging bio-derived aromatic diacid, 2,5-thiophenedicarboxylic acid (TDCA), was synthesized by a conventional two-step melt polycondensation method. Copolymers were random copolyesters with weight-average molecular weights (Mw) in the range from 65,400 to 84,100 g/mol. Their comprehensive properties, including thermal transition properties, thermal stability, mechanical properties, gas barrier properties, as well as optical transparency were systematically investigated. Rigid 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) cyclic diol contributed a positive effect to thermal resistance, leading to the glass transition temperature (Tg) growing from 65.3 °C of PETh to 85.3 °C of PET42Th. Furthermore, the mechanical properties, gas barrier properties and optical transparency were improved as diol segment was incorporated. Especially, all copolyesters displayed great ductility with elongation at break between 54 and 195 %. Meanwhile, the gas barrier properties of copolyesters were 3.9-fold to 16.3-fold for CO2 and 3.0-fold to 6.0-fold for O2 better than PET. Therefore, PETTh copolyesters might potentially substitute for commercial PET and they are extremely suitable for food packaging materials.

Furandicarboxylic Acid (FDCA): Electrosynthesis and Its Facile Recovery From Polyethylene Furanoate (PEF) via Depolymerization.

Replacing fossil fuels with renewable, bio-based alternatives is inevitable for the modern chemical industry, in line with the 12 principles of green chemistry. 2,5-Furandicarboxylic acid (FDCA) is a promising platform molecule that can be derived from 5-hydroxymethyl furfural (HMF) via sustainable electrochemical oxidation. Herein, we demonstrate TEMPO-mediated electrooxidation of HMF to FDCA in ElectraSyn 2.0 using inexpensive commercially available electrodes: graphite anode and stainless-steel cathode, thereby avoiding the often cumbersome electrode preparation. Key parameters such as concentration of HMF, KOH, and catalyst loading were optimized by experimental design. Under the optimized conditions, using only a low amount of TEMPO (5 mol%), high yield and Faradaic efficiency of 96% were achieved within 2.5 hours. Moreover, since FDCA is a monomer of the bio-based poly(ethylene furanoate), PEF, we aimed to investigate its recovery by depolymerization, which could be of paramount importance in the circular economy of the FDCA. For this, a new polar aprotic solvent, methyl sesamol (MeSesamol), was used, allowing the facile depolymerization of PEF at room temperature with high monomer yields (up to 85%), while the cosolvent MeSesamol was recycled with high efficiency (95-100%) over five reaction cycles.

Use of commercial synthetic filament waste to reinforce biobased poly(butylene succinate) with the aid of compatibilizers

Since poly(butylene succinate) (PBS) has low rigidity for engineering application, this research attempted to reinforce PBS with poly(ethylene terephthalate) (PET) and polyamide-6 (nylon6) filaments with the reservation of polymer toughness. Filaments were chopped to be short fibers (length of 2 mm to 4 mm) and melt compounded with PBS pellets in the weight ratio of 1 wt%, 5 wt%, and 7 wt% using a twin-screw extruder that the temperature profile was set high enough for melting only PBS matrix. Two types of compatibilizers; hexamethylene diisocyanate (HMDI) or hexamethylene diamine (HMDA) of 0.05 wt% were used to treat fiber surface. It was found that tensile modulus of PBS increased with respect to fiber concentration, which untreated PET fibers provided higher tensile modulus about 2% to 7%. Surface treatment of fibers with either HMDI or HMDA increased rigidity of the composites, while elongation at break and impact strength were also improved with respect to fiber concentration. Also, shifting in glass transition temperature of PBS by DMA indicated improved interfacial interaction, which HMDA treatment gave the best benefit for mechanical properties. Number-average molecular weight of HMDI-treated composites was closed to extruded PBS, however, those of HMDA-treated composites were reduced dramatically implying chain scission highly occurred. SEM micrographs revealed good interfacial adhesion obtained after fiber treatment. Crystallization of PBS studied by XRD showed that the crystal form was not affected by the compatibilizer.

Highly miscible bio-based poly(lactic acid)/acetylated cellulose ether ultrafiltration membranes with improved water permeances

Biopolymer-based membranes are eco-friendly alternatives to petroleum-based membranes. However, biopolymers often require harsh membrane fabrication conditions due to their low solubilities, which are incompatible with general non-solvent-induced phase separation (NIPS). Thus, establishing mild blending conditions for NIPS membrane production is needed. This study developed ultrafiltration membranes by blending poly (lactic acid) (PLA) and acetylated cellulose ether (ACE), both of which are derived from renewable resources, using NIPS under mild conditions. We investigated the effects of PLA proportion on the structural, chemical, and thermal properties of the blend membranes and assessed polymer miscibility using theoretical models. Results indicated excellent miscibility with a single glass transition temperature. The 1:1 PL A/ACE membrane demonstrated the lowest water contact angle of 45°, 35 % lower than that of the pure PLA membrane. Additionally, its pure water permeance was 179.4 LMH/bar, significantly higher than 103.4 LMH/bar of the pure PLA membrane. Flux recovery ratio at pH = 4 was 69.5 for the blend membrane as compared to 70.6 for the PLA membrane. At pH = 7, all membranes could be fully recovered via physical washing, even those fouled with bovine serum albumin. This study successfully fabricates PLA/ACE-based membranes with outstanding properties under mild conditions.

CoFe2O4 Nanoparticles on Bio-Based Polymer Derived Nitrogen Doped Carbon as Bifunctional Electrocatalyst for Li-Air Battery

Lithium-air batteries (LABs) are gaining attention as a promising energy storage solution. Their theoretical energy density of 3,505 Whkg−1 exceeds that of conventional lithium-ion batteries (500–800 Whkg−1). The commercial viability and widespread adoption of lithium-air batteries face challenges such as poor cycling stability, limited lifespan, and unresolved side reactions. In this study, we synthesized spinel CoFe2O4-decorated on bio-based poly(2,5-benzimidazole) derived N-doped carbon for electrocatalysts. Notably, strong metal-substrate interaction (SMSI) was observed through various characterizations. The bifunctional electrocatalytic activity and stability toward oxygen reduction reaction and oxygen evolution reaction were significantly enhanced by the SMSI, The LAB demonstrated a high discharge capacity of 18,356 mAhg−1 at a current density of 200 mAg−1, maintaining a remarkable discharge capacity of 1,000 mAhg−1 even at a high current density of 400 mAg−1 for 200 cycles. CoFe2O4-decorated on bio-derived ABPBI holds promise as a practical air-breathing electrode for high-capacity rechargeable LABs.

Chemical Structure and Thermal Properties versus Accelerated Aging of Bio-Based Poly(ether-urethanes) with Modified Hard Segments.

Aging of polymers is a natural process that occurs during their usage and storage. Predicting the lifetime of polymers is a crucial aspect that should be considered at the design stage. In this paper, a series of bio-based thermoplastic poly(ether-urethane) elastomers (bio-TPUs) with modified hard segments were synthesized and investigated to understand the structural and property changes triggered by accelerated aging. The bio-TPUs were synthesized at an equimolar ratio of reagents using the prepolymer method with the use of bio-based poly(trimethylene ether) glycol, bio-based 1,3-propanediol, and hexamethylene diisocyanate or hexamethylene diisocyanate/partially bio-based diisocyanate mixtures. The polymerization reaction was catalyzed by dibutyltin dilaurate (DBTDL). The structural and property changes after accelerated aging under thermal and hydrothermal conditions were determined using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA). Among other findings, it was observed that both the reference and aged bio-TPUs decomposed in two main stages and exhibited thermal stability up to approximately 300 °C. Based on the research conducted, it was found that accelerated aging impacts the supramolecular structure of TPUs.

Hydrothermal aging and soil biodegradation characteristics of biopolymer based sustainable composites

The current research endeavor examines the water absorption (in-service life) and soil biodegradation (end-of-the-service life) behavior of short sisal fiber (SF) reinforced poly (lactic acid) (PLA) and bio-based poly (butylene succinate) (bio PBS) composites. Samples were fabricated by extrusion-injection molding with varying sisal fiber loading of 10, 20, and 30 wt%. The water absorption test was conducted in distilled water at three distinct temperatures (5, 25, and 45 °C) for 336 h. The sorption behavior of composites was studied experimentally, and detailed diffusion kinetic behavior is discussed using Fickian diffusion models. The impact of fiber content and hydrothermal temperature on water diffusion and maximum water absorption was investigated in detail. A soil burial test was conducted in local farmland soil for 60 days to determine the influence of fiber content on the biodegradation characteristics of composites. After exposure to hydrothermal aging, it was concluded that fiber loading was most significant in affecting the maximum percentage of water absorption, whereas hydrothermal temperature was more relevant for higher water diffusion. Soil burial tests showed that SF/bioPBS composites degraded quickly as compared to PLA composites. Overall, composites made with bio PBS have shown an expected response than PLA composites in terms of water absorption and soil biodegradation.

Mechanical, Thermal and Performance Evaluation of Hybrid Basalt/Carbon Fibers Reinforced Bio-Based Polyethylene Terephthalate (BioPet) Composites

Looking at the dynamically developing market of engineering materials, there is a need to create newer functional composites. Today's economic situation related to high energy prices and environmental threats force industry to conduct sustainable production. Polymer composites based on plant raw materials are increasingly appearing on global markets, which are light, have good mechanical properties and are also pro-ecological. This work involved the production of hybrid composites based on bio-based poly (ethylene terephthalate) by means of injection molding. Two types of fibers were used simultaneously as the reinforcement phase: basalt fibers and carbon fibers in the amount of 5, 7.5, and 10 wt% of each. The produced materials were subjected to a wide range of mechanical, thermal, and functional characteristics. The experimental data were compared with the theoretical results which were calculated from different micromodels. The studies showed that with the addition of the filler, the mechanical properties of the produced composites increased, but the optimal content was found for composites with 7.5/7.5 wt% addition of fibers, where the improvement was – 81%, 337%, and 25%, for tensile strength, Young's modulus, and impact strength, respectively. In the produced materials, the thermal properties of composites were also improved, where the shrinkage decreased by min. half, and linear coefficient at least 3 times. Sufficient adhesion between the fibers and the matrix was confirmed by SEM images and mechanical micromodels, which confirmed the highest efficiency of reinforcement with a total content of 15 wt% of fibers. To assess the influence of extreme conditions on the behavior of composites, hydrolytic degradation was carried out, which showed that the addition of fibers will not increase water absorption. The mechanical tests of the incubated materials lead to the conclusion that the produced materials could be successfully used in long-term applications because the properties obtained during the tensile test have deteriorated by only max. 5%. The work showed for the first time the modification of bioPET using two types of fibers introduced simultaneously. Hybridization of bioPET with basalt and carbon fibers has shown that it is possible to create very durable composites with a high Young's modulus. The work showed that different fibers are responsible for increasing other parameters – basalt fibers increase strength, while carbon fibers increase Young's modulus. The research may contribute to the popularization of bio-based polymer composites that have high strength for low weight and are a cheaper equivalent than polyamide-based composites.

Synthesis and properties of novel biobased poly(hexamethylene 2,5-furandicarboxylate)-b-poly(diethylene glycol 2,5-furandicarboxylate) multiblock copolyesters

Two poly(hexamethylene 2,5-furandicarboxylate)-b-poly(diethylene glycol 2,5-furandicarboxylate) multiblock copolyesters were synthesized using two hydroxyl-terminated poly(hexamethylene 2,5-furandicarboxylate) (PHF-diol) and poly(diethylene glycol 2,5-furandicarboxylate) (PDEGF-diol) prepolymers in the presence of a chain extender hexamethylene diisocyanate. A series of techniques were employed to fully characterize the thermal, mechanical, and crystallization properties of the obtained multiblock copolyesters. 1H NMR results confirmed the expected multiblock structures. The combination of the two segments significantly improved the elongation at break of PHF without sacrificing the tensile strength. Moreover, the melt crystallization temperatures and melt points of the multiblock copolyesters only slightly decreased, due to the excellent crystallizability of the PHF segment. In addition, the PDEGF segment significantly influenced the tensile strength and hydrophilicity by forming hydrogen bonds between the adjacent molecular chains.

Machine learning algorithms to optimize the properties of bio-based poly(butylene succinate-co- butylene adipate) nanocomposites with carbon nanotubes

Poly[(butylene succinate)-co-adipate] (PBSA)-based materials are gathering much attention in the packaging industry, agriculture, and other fields owed to their biocompatibility and biodegradability. Nonetheless, poor thermal and mechanical properties of biodegradable polymers, such as PBSA, have hampered their wide-spread use. Herein, a simple, cost-effective and scalable solution to improve the mechanical properties of PBSA is reported by using functionalized single-walled carbon nanotubes (SWCNTs). Different SWCNT loadings have been incorporated in the PBSA matrix via simple solution casting, and the ultrasonication conditions have been optimized to attain a homogenous SWCNT dispersion. The nanocomposites have been characterized in detail by scanning electron microscopy (SEM), Infrared spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile and impact strength tests. Unprecedented increments in stiffness were found at low nanotube loadings, ascribed to the outstanding reinforcing capability of the SWCNTs combined with their superior modulus and strong interfacial adhesion with the matrix via H-bonding, polar and CH-π interactions. Further, four machine learning (ML) algorithms, Polynomial Regression (PR), Support Vector Machines for Regression (SVR), Gradient Boosting (GB) and Artificial Neural Network (ANN), were applied to predict their mechanical properties. The algorithm´s performance was assessed using analytical parameters such as the coefficient of determination (R2), the mean square error (MSE) and the mean absolute error (MAE). The developed models exhibited strong performance, achieving R2 values ranging from 0.69 to 0.99 across the evaluated properties. The results corroborate that even when the same prediction model is used, its performance varies depending on the physical property to be predicted. Thus, SVR, GB, PR, and ANN were found to be the most effective for estimating the Young’s modulus, tensile strength, elongation at break and impact strength, respectively. This research holds great potential for advancing the field of modelling the mechanical properties of polymeric nanocomposites and their practical applications in various industries such as food, pharmaceutical and biomedicine. The development of accurate models for predicting nanocomposite properties would cheapen, simplify and systematize their design and production processes, resulting in improved final products and more efficient development procedures.

Novel bio-based polyurethane elastomers for adjustable room-temperature damping property

The distinctive viscoelastic behavior of elastomeres can be exploited for reducing vibrations and noise. However, the utility of conventional rubber-based elastomers is limited by low glass transition temperature (Tg) and narrow adjustable damping range, which constrain the room-temperature damping property. Moreover, the majority of rubber-based elastomers are sourced from unsustainable petroleum-based resources. Therefore, designing bio-based materials with room-temperature high-damping property to replace conventional rubber-based elastomers is crucial. Herein, a novel bio-based polyurethane (bio-PU) elastomer with an adjustable damping-temperature range and room-temperature high-damping property is successfully synthesized from bio-based poly (trimethylene ether) glycol. The effects of molecular chain structure on the thermal properties, mechanical properties, and adjustable damping-temperature range of the bio-PU elastomers, along with the mechanisms underlying these effects, are elucidated in detail. As the content of hard segment increasing, the Tg of bio-PU elastomers significantly increases from −13.0 to 29.9 °C, effectively encompassing the damping temperature range within the room-temperature working range. This promising strategy for formulating bio-based elastomers with adjustable damping-temperature range can advance the sustainable growth of PU industry and broaden the scope of PU damping applications.

Investigate the Processability of Biobased Thermoplastics Used in Nonwoven Fabrics.

The Covid-19 pandemic increased enormously the manufacturing and usage of face masks and other personal protective equipment (PPE), resulting in accumulation of plastic waste and, thus, causing universal environmental concerns. In addressing the issue of waste reduction and finding alternatives for fossil-based products, investigation of different biobased and biodegradable polymers plays a crucial role. This study examines the processability characteristics of three commonly used biobased polymers available in the market: biobased poly(lactic acid) (PLA), partly biobased and biodegradable poly(butylene succinate) (PBS), and biobased high-density poly(ethylene) (BioHDPE). The investigation combines substantial polymer analysis with subsequent processability trials in two different spunmelt processes, namely, meltblow (MB) and the Nanoval technology, aiming to reveal the differences and difficulties in the processing behavior and pointing out advantages and/or disadvantages of the respective polymer/technology combination. In general, the observed processability behavior and outcomes indicate that within the used processes PLA exhibits superior processability compared to PBS and BioHDPE. Both the meltblow and Nanoval processing of PLA demonstrated a consistent production of fibers and efficient uptake without any compromise on the throughput. In contrast, the processing of PBS using Nanoval required the utilization of significantly elevated temperatures, as indicated by a rheological study. Furthermore, the rheological evaluation revealed that the viscosity of BioHDPE was excessively elevated, rendering it unsuitable for effective processing by the Nanoval method. The microfibers in the PLA-based meltblown fabric had a higher surface area, explaining why the PLA fibers were able to function as a barrier and, thus, contribute to the mitigation of air permeability adjustable between 500 and 1000 l·s-1·m-2 and thus competitive or even superior to PP nonwovens of the same fiber diameter and base weight (1480 l·s-1·m-2). Overall, these results showed that PLA can be an alternative raw material for fossil-based nonwovens of PPE applying, especially, the meltblown technique.

An investigation of novel biodegradable flexible copolyester derived from bio-based isosorbide: Synthesis and characterization of poly(butylene-co-isosorbide sebacate)

A series of fully bio-based poly(butylene-co-isosorbide sebacate) (PBISe) copolyesters are synthesized from sebacic acid (Se), 1,4-butanediol (BDO), and isosorbide (IS) via a two-step melt polycondensation method. The synthesized PBISe copolyesters are characterized using various techniques, including 1H NMR spectroscopy; GPC; FT-IR spectroscopy; HR-XRD; DSC; TGA; transparency, tensile, and tear strength testing; and rheological property analysis. The Mw and Mn values of the PBISe copolyesters are 126,000–148,000 and 50,000–63,500, respectively. The introduction of the rigid, bulky, and asymmetric IS unit disrupts the regularity and mobility of the polymer chain, resulting in a nearly linear reduction of the melting temperature, enthalpy, and crystallinity, from 66 to 42 °C, 81 to 37 J/g, and 41.4 to 19.0%, respectively, with an increase in the IS content from 0 to 30 mol% relative to the total diol concentration. The reduction of crystallinity without the formation of new crystal planes with the poly(butylene sebacate (PBSe) copolyester containing 30 mol% IS resulted in improved transparency (73.8% transmittance at 600 nm). Additionally, the PBISe copolyesters exhibit Tonset and Tmax in excess of 405 °C and 425 °C, respectively, as well as shear-thinning and viscous melt-flow behaviors, making them suitable for melt processing. The tensile strength and elongation at break of the hot-pressed films of the IS-added PBISe copolyesters with ≤16% content are 31.6–36.3 MPa and 639.2–809.9%, respectively. The developed PBISe copolyesters have great potential as bio-based, biodegradable, and flexible materials for packaging and coating applications with low processing temperatures.

Bio-based poly(lactic acid) foams with enhanced mechanical and heat-resistant properties obtained by facilitating stereocomplex crystallization with addition of D-sorbitol

The preparation of bio-based poly(lactic acid) (PLA) foams with high mechanical properties and heat resistance is of great significance for environmental protection and green sustainable development. In this paper, D-sorbitol (DS) containing six hydroxyl groups was introduced into poly(l-lactide) (PLLA)/poly(d-lactide) (PDLA) blends for first time to promote the formation of stereocomplex (SC) crystals, which could improve the foaming behavior and enhance mechanical properties and heat resistance of PLA foams. The results showed that DS could improve the formation efficiency and crystallinity of SC crystals by enhancing the hydrogen bonding between the enantiomeric molecular chains. Furthermore, the compression modulus and interactions Vicat softening temperature of the PLLA/PDLA/DS blend foam increased about 854% and 16% compared to the pure PLLA foam, respectively. Besides, when the annealing process was introduced, the compression and heat resistance of the PLA foams increased further. This study provided a feasible strategy for the preparation of bio-based and biodegradable PLA foams with outstanding compressive and heat resistance properties.