Chemistry and Materials Science

Abstract: In recent decades, due to the rapid development and application of wireless communication, flexible electronics, and smart devices, electromagnetic interference (EMI) and radiation pollution have been intensified, creating an urgent demand for efficient EMI shielding materials. Carbon nanostructures such as graphene and carbon nanotubes are considered promising candidates due to their excellent properties, such as high electrical conductivity, low density, large specific surface area, and flexibility. This work reports our recent results in the design and testing of polymer nanocomposites with irradiated hybrid carbon nanostructure (graphene/multi-walled carbon nanotubes) used as EMI shielding materials. Five representative composites with varying filler loadings (AH of 15% and AM1 of 20 wt%), thicknesses (0.208–0.48 mm), and e-beam irradiation doses (from 50 to 400 kGy) were systematically characterized using SEM, FTIR, TGA/DSC, and vector network analyzer (VNA) measurements in the S-band (2.65–3.90 GHz). The effects of different e-beam irradiation doses and hybrid carbon content on conductive network construction, interface engineering, and porous or layered structures on EMI shielding performance are discussed. Experimental results show that all studied composites exhibited strong absorption-dominant behavior (SEA), while the multiple reflection component (SEM) was found to be negligible. Both filler loading and sample thickness significantly enhanced shielding performance, with a pronounced synergistic interaction observed between these parameters. A quadratic Response Surface Methodology (RSM) model was developed to correlate SET with thickness and filler content, yielding high predictive accuracy (R2 > 0.99). The model enables efficient optimization of composite design for targeted shielding levels.

Abstract: Additive Manufacturing (AM) process parameters significantly influence the thermal, mechanical, and surface roughness properties of printed parts. While experimental characterization is highly accurate, it is often excessively time-consuming and costly, hindering the development of scalable predictive models. This study adopts a Materials Informatics approach to curate a multi-sourced benchmarking dataset comprising 543 entries for ABS, PLA, and TPU filaments, integrating data from web-scraping (WSDS), literature (LDDS), and manufacturer technical datasheets (MTDS). Data cleaning included outlier detection via Tukey’s fences and the evaluation of imputation strategies, with K-Nearest Neighbors (KNN) consistently outperforming simple mean/median methods. We evaluated three regression models, Random Forest (RF), Ridge Regression (RR), and Support Vector Regression (SVR), using a nested cross-validation pipeline to predict tensile strength, elongation, and surface roughness. The results reveal significant data gaps in existing literature, with missingness exceeding 60% for critical parameters like fan speed and wall thickness. While the Random Forest model achieved high predictive accuracy for bulk mechanical properties, specifically a test-set R2 of 0.995 for PLA elongation, all models struggled with surface roughness, often yielding negative R2 values. This suggests that current process descriptors are insufficient to capture the stochastic nature of surface morphology. This work provides a foundational benchmarking dataset for the research community and highlights the necessity for stricter data mining protocols and more sophisticated feature engineering to achieve reliable predictive quality in material extrusion (MEX) polymers.

Abstract: Optical spectroscopy provides several useful information about polymeric ultrathin films by combining interferometric and optical absorption data contained in the UV-Vis-NIR spectra. In particular, the UV-Vis-NIR spectrum of an ultrathin polymeric film contains information about the film thickness, structural disorder, bandgap energy, type of electron transition model (direct/indirect, allowed/forbidden), cutoff wavelength (i.e., the opaque/transparent switching wavelength), etc. Here, these properties have been determined for a model semi-crystalline polymer (polyethylene terephthalate, PET) in form of ultrathin film before and after a mild mechanical deformation treatment (manual stretching). It has been found that E_U and E_g parameters are not strictly depending on mechanical deformation due to their main dependence on chemical composition/constitution of the polymer; consequently E_g can be used for polymer identification in the case it has a dielectric nature.

Abstract: With the Green Deal and the Circular Economy Action Plan, the European Union aims to replace half of the fossil-based raw materials in plastics with sustainable alternatives by 2030. In the plastic pipe industry, the use of post-consumer recyclates (PCR) remains very limited due to reduced material quality, economic hurdles, limited availability, non-specific classification requirements, and a lack of testing standards. This paper presents two interconnected contributions to the quality-assured use of PCR for buried utility infrastructure made from PE, PP, and PVC-U. First, a methodological framework, based on EN 13476, defines suitability as the intersection of material classification and application-specific requirements profile. A review of the current regulatory and technical situation reveals a systemic discrepancy: requirements profiles are oriented toward virgin material, while the scope of classification for PCR remains insufficiently defined. As a result, PCR is either used without adequate suitability assessment or blended with fillers, which limits the recyclability. Secondly, the review focuses on additive strategies, including restabilization, compatibilization, chain modification, and recyclate-compatible functional additives. These strategies are among the main technical solutions for closing the gap between PCR properties and the product's requirements, reducing filler dependency, and enabling the long-term use of PCR in safety-critical applications.

Abstract: Micro-nonuniformity, as a fundamental natural property, is widespread across a range of microscopic aggregate systems, such as polymer systems, biomacromolecular systems, and nanosystems. However, the construction of micro-nonuniform molecular systems has not yet been realized at the level of organic molecules with well-defined structural compositions. Inspired by the “chemical space” concept, I recently reported a study of the single-molecule mixture state; in this paper, I provide a detailed discussion of micro-nonuniformity and the hypothesis of a “single-molecule mixture state”, and propose a possible experimental approach for testing it.

Abstract: Currently, plastic pollution is a growing global issue due to its non-biodegradability, increasing demand for eco-friendly alternatives such as bioplastics. This study explores the development of bioplastic films from chickpea starch using a three-step molding process. In the first step, starch is extracted from chickpeas. The second step involves hydrolysis and plasticization of starch with glycerol in different ratios. In the final step, the modified starch is blended with polyvinyl alcohol (PVA) in varying ratios to produce the bioplastic films. The optimal formulation, CPS 1:2:2, exhibited strong performance (3.63 MPa TS, 623% EA, and 70.1° WCA). The bioplastic showed good physicochemical characteristics, confirmed by FTIR analyses, mechanical performance, and water contact angle, and demonstrated biodegradability, as confirmed by FTIR and SEM morphology.

Abstract: Shape-memory polymers (SMPs) are gaining significant attention for their ability to recover predefined shapes via external stimuli. Among thermally activated systems, biodegradable blends of polylactic acid (PLA) and polycaprolactone (PCL) are particularly promising for biomedical devices and soft actuators. This study develops a thermo-mechanical theoretical model to investigate the shape-memory behavior of a PLA/PCL composite blends under controlled thermal cycling. The framework integrates transient heat transfer, temperature-dependent elasticity, and viscoelastic dynamics to predict temperature evolution, deformation, and internal stress. The thermal response is computed via Newton’s law of convection, while the mechanical transition is described by a sigmoidal temperature and crystallinity-dependent Young’s modulus. Beam bending theory is employed to evaluate the spatial distribution of strain and stress. A parametric sensitivity analysis was performed to evaluate the influence of different parameters including the crystallinity grade, the convective heat transfer coefficient, glass transition temperature, and viscoelastic recovery constant. The theoretical study accurately reproduces the shape-memory cycle, quantifying performance through fixation and recovery ratios. This model provides a robust tool for the rational design and optimization of biodegradable smart polymer structures.

Abstract: Five modifications of polytetrafluoroethylene (PTFE) are considered as a modern alternative to PTFE as sliding layers of bridge bearing parts. Radiation-modified PTFE without additives and with nano-additives, as well as composites based on PTFE with bronze inclusions and nanomodified carbon fiber fillers, were investigated. Ultra-high-molecular-weight polyethylene (UHMWPE) and classic pure PTFE were considered as control samples. The thermomechanical properties of the materials were studied within the framework of dynamic mechanical analysis in the operating temperature range of bridge structures [−40; +80] °C. The exit zones from the linear theory of viscoelasticity were established for all the materials considered. Temperature dependencies of the storage module and the loss module were determined. Thermo-viscoelastic models of material behavior were constructed using a numerical identification procedure, experimental data, and simulation models. The thermomechanics of materials during the deformation of the spherical support part of the bridge were analyzed. Temperature dependencies of the parameters of the contact stress-strain state were determined with an average coefficient of determination R2 = 0.97 and an average error size RMSE = 0.092.

Abstract: Lignin is an abundant aromatic biopolymer generated as a major by-product in lignocellulosic biorefineries, and its efficient valorization is essential to improve process sustainability and economic viability. Among current upgrading strategies, the conversion of lignin into lignin-derived biochar (LDB) has emerged as a promising route due to its high carbon yield, scalable production, and tunable physicochemical properties. This review examines lignin-to-biochar conversion within the biorefinery context, emphasizing the interconnections between lignin structure, thermochemical processing, and resulting material properties. The influence of different technical lignins (kraft, organosolv, and soda) and conversion pathways, including pyrolysis and hydrothermal carbonization, is discussed. LDB materials exhibit strong potential in the removal of emerging contaminants, such as pharmaceuticals, pesticides, and PFAS, as well as in controlled release systems for agrochemicals. Despite recent progress, key challenges remain, including limited reproducibility across studies, insufficiently established predictive structure-property relationships, and the need for validation under realistic environmental conditions. Overall, LDB represents a scalable and versatile platform for lignin valorization, contributing to the development of integrated and sustainable biorefineries within a circular bioeconomy framework. This review provides a conceptual framework for the rational design of lignin-derived biochar within next-generation biorefineries.

Abstract: Biodegradable polymer systems based on poly(3-hydroxybutyrate) (PHB) and poly(butylene adipate-co-terephthalate) (PBAT) have attracted significant attention for fused deposition modeling (FDM)-based orthopedic applications due to their biodegradability, tunable mechanical behavior, and potential to reduce stress-shielding effects associated with metallic implants. However, the immiscibility of PHB/PBAT blends, limited melt stability, and poor balance between stiffness and ductility restrict their processability and functional performance. In this study, rheology was employed as the central design parameter to establish the relationship between reactive compatibilization, melt structure evolution, filament formation, printability, mechanical response, and degradation behavior in PHB/PBAT-based systems. PHB/PBAT blends containing varying Joncryl® ADR and MgO nanoparticle contents were prepared through reactive melt blending, followed by filament extrusion and FDM processing. FTIR analysis confirmed epoxy-mediated reactions between Joncryl and polyester chain ends, indicating chain extension, branching, and enhanced interfacial interactions. Rheological analysis demonstrated that reactive compatibilization significantly increased storage modulus, complex viscosity, melt elasticity, and relaxation times, particularly at low frequencies, indicating the formation of a more interconnected viscoelastic network favorable for stable filament extrusion and shape retention during FDM processing. Stress relaxation measurements further confirmed delayed stress dissipation and enhanced melt structural recovery in compatibilized systems. In contrast, MgO incorporation introduced rheological heterogeneity and altered relaxation dynamics through polymer-filler interactions and localized chain confinement. Mechanical characterization revealed a transition from brittle PHB behavior to ductile PBAT-rich systems. Among the investigated formulations, PHB/PBAT/J0.3 exhibited the most favorable balance between tensile strength, elongation, toughness, and filament stability, while excessive MgO loading reduced ductility and impact resistance despite modest stiffness enhancement. SEM observations demonstrated improved phase morphology and interfacial adhesion after reactive compatibilization, whereas MgO-containing systems exhibited increased structural heterogeneity. Thermal analysis showed that compatibilization modified crystallization behavior through chain branching and reduced crystallinity, while MgO influenced crystallization efficiency and degradation pathways. In vitro degradation in phosphate-buffered saline (PBS) solution at 37 °C demonstrated controlled degradation behavior and gradual pH evolution over 42 days. The results demonstrate that reactive compatibilization governs the viscoelastic state required for stable FDM processing and balanced mechanical performance, while MgO provides secondary control over stiffness and degradation behavior. The developed biodegradable PHB/PBAT-based systems show promising potential for additively manufactured orthopedic and biomedical applications where controlled degradation, flexibility, and processability are required.

Abstract: Polymers enable countless modern technologies, yet vast regions of their chemical space remain unexplored. Traditional polymer discovery relies on chemical intuition, ingenuity, and experience (with a healthy dose of serendipity), yet it fails to leverage millions of potentially accessible and synthesizable polymer structures. Here, we present RxnChainer, a digital methodology integrating virtual polymer generation, retrosynthetic analysis, and post-polymerization modification to systematically explore synthetically accessible polymer space. Using commercially available monomers from the Toxic Substances Control Act (TSCA) and ChEMBL databases and RxnChainer, we generated over 289 million hypothetical polymers across 44 polymerization pathways spanning 32 polymer classes, including polyamides, polyimides, polyesters, and polyethers. Comparison with the known (i.e., previously synthesized) spectrum of polymers revealed that a significant portion of these new synthesizable structures are novel, i.e., previously unknown and unexplored. We demonstrate the methodology's versatility through automated retrosynthetic planning for 30,000 polyesters and targeted functionalization via four post-polymerization modification pathways incorporating vinyl and nitrile pendant groups. The resulting datasets enable downstream tasks such as property-driven screening, application-specific design, and training of generative models.

Abstract: In this study, the effect of incorporating maltodextrin into films composed of thermoplastic starch and chitosan was evaluated with the aim of improving their physicomechanical properties. X-ray diffraction revealed greater organization in sample TPS-CH-M3 compared with TPS-CH-M0 and TPS-CH-M5, indicating a balanced semicrystalline structure. Thermal analyses showed an increase in the glass transition temperature from 63.0 °C to 72.6 °C and a shift of the main degradation step from 308 °C to 311 °C, reflecting enhanced thermal stability. The contact angle decreased from 89.5° to 74.0°, confirming increased hydrophilicity. SEM micrographs revealed a homogeneous surface in TPS-CH-M0 and controlled roughness in TPS-CH-M3. Mechanical tests recorded the highest tensile strength (12.5 MPa) and elongation at break (18%) for TPS-CH-M3. FTIR spectra showed physical interactions without new chemical bands, and colorimetric analysis indicated an increase in yellow tonality, which is suitable for packaging and coatings of light-sensitive foods.

Abstract: Increasing regulatory demands for high-quality plastic recycling create a strong need for novel tracer systems that enable reliable polymer identification and sorting. This feasibility study evaluates germanium nanocrystals (GeNCs) as Raman-detectable tracer materials in polypropylene (PP). The synthesis of GeNC/PP composite materials possessing various GeNC contents via a solvent-based intercalation process followed by compounding and injection molding is reported. Hydride-terminated GeNCs were synthesized and subse-quently functionalized with dodecyl ligands to ensure chemical stability, compatibility with the polymer matrix, and processability under conventional melt-processing condi-tions. The dodecyl-functionalized GeNCs were successfully stabilized and homogeneous-ly integrated into the PP matrix. Raman spectroscopy demonstrates the clear detection of GeNCs within the composites through a characteristic Ge–Ge optical phonon mode at 296 cm⁻¹, which is well separated from the intrinsic Raman bands of polypropylene. The Ra-man signal intensity increases systematically with increasing GeNC concentration. Ra-man mapping reveals an overall homogeneous distribution of the nanocrystals within the polymer, while a slight tendency toward agglomeration is observed at higher loadings. These results demonstrate that GeNCs are well suited as optically detectable tracers for polypropylene and can be reliably identified using Raman spectroscopy, highlighting their potential for tracer-based sorting concepts in advanced recycling and digital material passport applications.

Abstract: ABS is widely used as engineering plastic, but extensive use generates a significant amount of waste which is difficult to recycle due to material's complex composition. Physical recycling of ABS using TNO Möbius dissolution technique has been used here to separate pure SAN polymer, from PBR, and other substances. Relationships between properties and composition of the original materials were investigated as a starting point for evaluation of the effects of recycling on the quality of recycled materials. Three ABS materials were used in the recycling process to produce pure SAN polymers. The recycled SANs were then melt-blended with fresh masterbatch. The final ABS ma-terials had the same composition which allowed to investigate whether SAN recycled from different sources causes differences in properties of the final ABS materials. All properties of ABS materials made with recycled SAN are similar regardless of the source of SAN. Substances were quantified in the original ABS materials and in SAN polymers obtained by the recycling process. The substances were largely removed from all materials except one. The main conclusions from this study are that SAN polymer obtained by physical recycling from different sources does not affect properties of the final ABS material and the TNO process successfully separates SAN from other substances.

Abstract: Exploring a possibility of β-myrcene (MY) incorporation in propene copolymerization has been studied in the presence of phenoxide-modified half-titanocene, Cp’TiCl₂(O-2,6-ⁱPr₂-4-C₆H₃) (Cp’ = Cp*, Me₃SiC₅H₄), and ketimide-modified half-titanicene, Cp’TiCl₂(N=C^tBu₂) (Cp’ = Cp*, Cp), catalysts. The permethylated Cp* catalysts exhibited good catalytic activities in the copolymerizations but afforded the copolymers up to 3 mol% MY incorporation; the other catalysts showed the negligible activities. The resulting copolymers were amorphous and exhibited glass transition temperatures (T_g) that de-creased with increasing the comonomer (MY) content, reaching values as low as −17 °C.

Abstract: Sodium alginate was extracted from beach-cast Sargassum spp. collected along the coast of Puerto Progreso, Yucatán, Mexico, using two established pretreatment routes based on formaldehyde and ethanol. The study was designed to determine how extraction methodology influences alginate molecular structure and, consequently, its rheological performance. The ethanol-based route provided the highest extraction yield (up to 19.87%), whereas the formaldehyde route afforded alginate with higher intrinsic viscosity and viscosity-average molecular weight. Structural characterization by ¹H NMR revealed clear differences in monomer composition and sequence distribution, with ethanol-extracted alginate showing higher guluronic acid content, lower M/G ratio, and greater abundance of G-rich blocks. These structural differences were directly reflected in the viscoelastic behavior of Ca²⁺-crosslinked hydrogels. Alginate obtained by the ethanol route produced stiffer gels with the highest storage modulus, consistent with enhanced ionic crosslinking promoted by G-block-rich sequences, although with limited macroscopic cohesion due to lower molecular weight. In contrast, alginate obtained by the formaldehyde route showed a more balanced mechanical response associated with improved chain connectivity and network integrity. FTIR analysis confirmed the preservation of the characteristic functional groups of alginates in all samples. Overall, the results demonstrate that beach-cast Sargassum from the Yucatán coast is a viable source of sodium alginate and that extraction route is a key parameter governing its microstructure and rheological performance. These findings provide a structure–property framework for the valorization of stranded Sargassum biomass as a source of functional polysaccharides.

Abstract: Chemical recycling of polyolefins is essential to mitigate plastic waste accumulation and promote circular economy strategies. Among the various chemical recycling pathways, catalytic pyrolysis, tandem catalyst systems, ethenolysis, hydrocracking, and hydrogenolysis have emerged as promising approaches for converting polyolefin waste into valuable hydrocarbons, including gaseous, liquid, and solid products. This review provides a survey of recent research on these methodologies, with a particular focus on the production of light gaseous hydrocarbons (C1–C4), bypassing the intermediate pyrolysis oil stage, which is often associated with contaminants and increased processing costs. The novelty of the present work lies in its emphasis on gaseous fractions, in contrast to most existing studies that primarily target oil recovery. Aspects such as catalyst selection, reaction conditions, and product distribution are analyzed. Additionally, the current Technology Readiness Level (TRL) of the studied processes, their relative advantages, limitations, and perspectives for industrial applications are discussed. The analysis highlights catalytic pyrolysis with zeolites as the most mature and scalable technological alternative for manufacture of light compounds directly from polyolefin waste, while tandem catalyst systems and ethenolysis constitute promising but still emerging alternatives for targeted gas production.

Abstract: Concerns about the environmental and health impacts of plasticized PVC have created a clear demand to find alternative packaging materials for medical and pharmaceutical use. As polyolefin-based alternative, we blended polypropylene-ethylene copolymers of different, ethylene content-controlled, phase structure, with styrene-ethylene/butylene-styrene block copolymer (SEBS), as modifier, the latter being elastomeric and mechanically acting as cross-linked rubber due to a unique microphase separated morphology of hard spherical PS domains dispersed in the soft EB phase. Tests with injection-molded samples and cast films demonstrated promising combinations of flexibility, durability, and transparency—qualities essential for soft medical packaging like infusion pouches and blow-fill-seal bottles. For the desired level of flexibility (reflected by a flexural modulus of about 150 MPa), blends with two random-heterophasic (RAHECO) copolymers achieved this with only 15–25 wt.-% SEBS, compared to 37 wt.-% needed for a single-phase random copolymer (RACO); these blends also exhibited greater toughness. In contrast, a standard impact copolymer (HECO), with its more crystalline structure, required a higher modifier content of 45 wt.-% SEBS. Film morphology analysis indicated a gradual shift in disperse phase structure and orientation, leading to phase inversion at the highest SEBS content—without negatively affecting transparency.

Abstract: Flexible electrode materials with tailored electrical and mechanical properties are essential for reliable electrocardiographic (ECG) sensing. In this work, p-toluenesulfonic-acid-doped polypyrrole (PPy–TSA) films were modified using polymeric and inorganic fillers, as well as their combinations (polyethylene glycol, graphene, carbon nanotubes, and zeolite), to tune their functional performance. The reference PPy–TSA film exhibits typical morphological and chemical characteristics of doped polypyrrole and serves as a reliable baseline for comparison. All composite films retain electrical conductivity within the range required for ECG applications while showing improved mechanical compliance. Based on the optimized balance between electrical and mechanical properties, flexible ECG electrod were fabricated using the TSA doped PPy based composite film. ECG recordings obtained with the several proposed electrodes show good agreement with those acquired using a commercial ECG electrode, demonstrating the potential of PPy-based composite films for flexible bioelectronic sensing applications.

Abstract: The rapid accumulation of plastic waste has become a major environmental concern, while at the same time it is necessary to create opportunities to rethink how these materials can be reintegrated into productive use, particularly within the construction sector. This study provides a sustainability-oriented review of the reuse of plastic waste, both fossil-based plastics and bioplastics, as building materials, with a specific emphasis on structured decision-support approaches. A systematic literature review was conducted to identify and analyze peer-reviewed studies examining the incorporation of plastic waste into construction applications, including composites, panels, insulation systems, and structural or non-structural components. Particular attention is given to research applying Multi-Criteria Decision Analysis (MCDA) and SWOT analysis as tools for evaluating sustainability performance across environmental, economic, technical, and social dimensions. The findings indicate that recycled plastic and bioplastic-based construction materials can deliver significant advantages, such as diverting waste from disposal pathways, reducing reliance on virgin resources, and, in certain cases, enhancing durability. However, these materials also face important challenges, including limitations in recyclability, concerns related to fire performance, regulatory acceptance, and uncertainties in end-of-life management. MCDA-based studies underscore the critical role of criteria selection and weighting, especially regarding environmental impact reduction and cost competitiveness, in shaping final rankings and decision outcomes. SWOT analyses, in turn, offer complementary strategic insights by highlighting issues related to market readiness, regulatory frameworks, and implementation barriers. By integrating these decision-oriented evaluation approaches, this review contributes to more transparent and evidence-based material selection processes and supports policy development aimed.