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This work presents the use of natural rubber (NR) grafted with poly(vinyl propionate) (NR-g-PVP) as an alternative compatibilizer in silica-filled NR compounds. The effects of NR-g-PVP with 10, 20 and 30% grafting on the properties of NR compounds were studied and compared with a commercial coupling agent (bis[3-(triethoxysilyl)propyl] tetrasulfide, TESPT). NR-g-PVP was compatible with silica and NR. The NR-g-PVP reduced filler-filler interactions and increased fillerrubber interactions. The crosslink density decreased with the percentage of grafting due to the steric hindrance. The compatibilization affected the physical and mechanical properties. The interactions of NR-g-PVP with silica via hydrogen bonding and subsequent vulcanization prevented undesirable filler-filler interactions and reduced the absorption of accelerators or basic materials. It caused a good dispersion of silica in the NR matrix and improved physical and mechanical properties. A 10% grafting (G10) was suitable for the compatibilizer in a silica-filled NR compound, showing the largest improvements in tensile properties, tear strength, and hardness. However, TESPT provided better properties than G10.

Zinc complexes have a considerable impact on human health and the environment, especially on aquatic wildlife. One of the primary sources of zinc release to the environment is worn rubber particles from tires. The environmental footprint of zinc oxide (ZnO) during production, use, and landfilling has prompted researchers to reduce its use in rubber formulations due to ecological and economic concerns. In this study, composite ZnO materials where ZnO particles are coated on precipitated calcium carbonate (CaCO3) are used in styrene butadiene rubber/butadiene rubber (SBR/BR) compounds, and their performance is compared with white seal ZnO and active ZnO. Trial compounds are prepared on a laboratory scale using composite ZnO materials with ZnO:CaCO3 ratios of 40:60, 60:40, and 90:10, and control compounds with white seal and active ZnO. All compounds are tested to evaluate their curing and physico-mechanical properties. It is observed that the surface area of ZnO plays an essential role in crosslink density and, hence, compound performance. Trial materials have no negative effect on the curing and mechanical properties of the compounds. Thus, it is concluded that composite ZnO materials can be used as alternatives to both white seal ZnO and active ZnO. They have environmental and economic advantages due to their lower ZnO content. The compound recipe has the potential to be used for tire tread compounds.

Novel nonterminal liquid crystalline epoxy resin has been synthesized, and its structure and nature have been determined via nuclear magnetic resonance (NMR) and polarized optical microscopy (POM). Then, it was cured with the use of 4,4′-diaminodiphenylmethane (4,4′-DDM). The curing process has been investigated via differential scanning calorimetry (DSC) and infrared spectroscopy (FTIR) methods. Polymerization has been conducted with (1.2 T) and without the presence of a strong magnetic field. The properties of the obtained polymers have been described using DSC, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), dielectric spectroscopy (DS) and X-ray scattering studies (WAXS/SAXS). It has been proved that the magnetic field induces molecular ordering and increases the glass transition temperature (Tg) by over 20 °C. The obtained ordered polymers are thermally stable up to over 300 °C, undergo vitrification at slightly elevated temperature (37.5 °C), and their electrical conductivity rises significantly at the transition to an elastic state, which, among other possibilities, makes them a proper candidate for a smart, lightweight polymers with tuneable properties by a subtle temperature rise and possibility of tailoring its structure by a magnetic field.

Smart materials represent an emerging and highly exploited category, particularly in the creation of textiles that can sense and respond to various external stimuli, such as temperature or humidity. This study introduces for the first time the hygroscopic elongation and drying shrinkage properties of stimulus-responsive single-component polyamide (PA) fibers copolymerized with polyetherdiamine and diethylenetriamine (DETA). PA copolymers containing 5–15% polyetherdiamine were comprehensively characterized, including nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FT-IR), relative viscosity, and differential scanning calorimetry (DSC) analyses. Subsequently, these PA copolymers were successfully melt-spun into fibers and knitted into double-layered fabrics. PA fibers containing 15% polyetherdiamine showed significant results, with a moisture-absorbing elongation of 15.6% and a drying shrinkage of 94.9%. The Qmax and moisture regain of the PA fabric are 0.206 W·cm–2 and 4.4%, respectively. These moisture-driven, fiber-based smart textiles exhibit changes in breathability and shape retention at different humidity levels, thereby maintaining a more comfortable microclimate. Such textiles have great potential for widespread use in clothing, helping to improve comfort and adaptability.

Controlled development of novel materials fosters innovation in the electrical sector. The hybrid materials based on magnetic nanocellulose are intriguing since they have many uses in electronics, catalysis, medicine, and ecology. The study investigated the structure and morphology of hybrid nanomaterials made from nanocellulose and cobalt ferrite. The nanocellulose was prepared by TEMPO-oxidation and the cobalt ferrite was prepared by sol-gel auto-combustion method. Using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) techniques, it was determined how nanocellulose loading affected the crystal structure of the synthesized composite. To ascertain the variation in the component concentrations, scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDAX) are used. Composite with a higher concentration of nanocellulose fibers (NCF) show lesser particle size, and this may account for the smaller size of nanocellulose fibers, and attachment of nanocellulose nanofibers over the surface of porous cobalt ferrite (CF) found in SEM images.

The structure and property relationships of graft copolymers from natural rubber (NR) and polymethyl methacrylate (PMMA) crosslinked with a phenolic resin were investigated. The NR grafted with PMMA (NR-g-PMMA) having different grafting levels was initially prepared by emulsion polymerization before compounding and vulcanization. Then, proton nuclear magnetic resonance and transmission electron microscopy were used to verify the resultant NR-g-PMMAs. The graft copolymers crosslinked with phenolic resin exhibited improvements in various properties. Tensile modulus and tensile strength increased at least 18 and 95%, respectively, over the un-grafted counterpart and further improved with grafting percentage, while the elongation at break decreased accordingly. Storage modulus in rubbery plateau increased while tanδ peak height decreased with PMMA content. Moreover, the thermal stability of the graft copolymers was also improved over that of the plain NR at least 23 °C, depending on MMA contents. These improvements are tentatively attributed to the strong adhesion between NR and PMMA phases, based on interactions between the functional groups of PMMA and hydrogen bonding between phenolic resin crosslinker and PMMA. The results clearly suggest that the phenolic resin could be an effective crosslinker for NR-g-PMMA.

Thermoplastic vulcanizates (TPVs) were prepared by blending natural rubber (NR) and polypropylene (PP) using dynamic sulfur curing systems with varying accelerator/sulfur ratios: 0.5/2.5, 1.5/1.5, and 2.5/0.5 phr, categorized as conventional (CV), semi-efficient (semi-EV), and efficient (EV). The onset of dynamic vulcanization closely corresponded with scorch time in statically cured NR compounds. Mixing torque decreased over time, reflecting reversion patterns in static curing. The CV system exhibited the highest reversion tendency due to polysulfide linkage breakdown, forming stronger but shorter crosslinks. Dynamic vulcanization induced higher reversion than static curing, influenced by shear and extensional forces. Curing systems caused crosslinking rates, reversion, and crosslink density and distribution variations. Unlike statically cured NR, PP-extracted TPVs exhibited an inverse trend in total crosslink densities and distributions; TPVs primarily comprised shorter crosslinks with opposed total crosslink densities ranked EV > semi-EV > CV. This trend is strongly correlated with superior mechanical strength, toughness, storage modulus, viscosity, and rubber elasticity in the EV-cured TPV. EV system also had the smallest vulcanized NR domains in the PP matrix.

Flexible rubber composites based on blends of bromobutyl rubber (BIIR)/epoxidized natural rubber (ENR) filled with a hybrid filler of layered double hydroxides (LDH)/carbon nanotubes (CNT) were prepared, which may be of interest for use in tires and inner liner. An imidazole mixture of butyl-imidazole and 1H-imidazole was proposed to achieve reversible non-covalent networks consisting of ionic clusters and hydrogen bonding that led to the self-healing properties of each blend phase. The objective of the present work was to characterize the effects of selective modification of the rubber blends by imidazole and selective wetting of the hybrid filler on the mechanical and electrical properties and the self-healing effectivity. The wetting concept used to characterize the selective wetting of a single filler in a rubber blend was further developed for a hybrid filler in BIIR/ENR blends. During the one-step mixing and the masterbatch mixing process, re-localization of the hybrid filler between the blend phases under thermodynamic driving forces was observed. Within the specified mixing time, the thermodynamic equilibrium state of filler localization could not be reached. The nearly uniform distribution of LDH in both blend phases and the preferential localization of CNTs in the ENR matrix were found to be essential in giving the BIIR/ENR blends the best combination of self-healing properties and electrical conductivity. The high electrical conductivity of the composites can be exploited to generate a high temperature locally at the damage site inside the rubber samples when an electrical voltage is applied, resulting in an acceleration of the self-healing process.

The effect of swelling and plasticizer content of a plastic, as well as the ethanol content of the food simulant on the migration kinetics of three stabilizer-type additives from polylactic acid (PLA)-based food contact plastics has been investigated. The results proved that the parameters that affect the diffusion of substances inside the polymer matrix, i.e., swelling, plasticization, and the size of migrants, are the decisive factors in the migration from PLA to ethanolic food simulants. Both swelling and migration were negligible when ethanol 10% (v/v) was used. Contrarily, the specific migration limits of Commission Regulation (European Union, EU) No. 10/2011 were exceeded in ethanol 50% (v/v) for all investigated stabilizers. Migration was promoted by plasticization, but this effect could only be observed when the applied food simulant swelled the plastic (at least 20% (v/v) ethanol content). The dependence of the plasticizer’s migration-enhancing effect on the swelling has not been shown before. When the plasticization caused increased migration, it also led to specific migration limit exceeding within a shorter period of time. It happens even if PLA-based plastics are dedicated to the storage of hydrophilic food, which is the most common application area of these products. These results can support the improvement of both consumer safety and active packaging development.

The impact resistance of four polypropylene impact copolymers (ICPs) with multi-phase structures and widely differing characteristics was related to their structure. Blends were prepared from one of them and a high-density polyethylene (HDPE) to improve impact strength further. The structure of the materials was characterized by microscopy and dynamic mechanical thermal analysis. Mechanical properties were determined by tensile and impact testing, while local deformation processes were followed by volume strain measurements. The results obtained in the study proved that the shear-yielding of the matrix contributes the most among local processes to the increase of impact strength, while cavitation has a small effect on this latter property since its energy absorption is negligible. Both increasing elastomer content and decreasing particle size favor shear-yielding, thus improving impact strength. Considering the importance of elastomer content and elastomer particle size, a simple but very good model was created describing the dependence of the impact strength of ICPs on these latter two factors by using linear regression analysis. Although the addition of HDPE increases the fracture resistance of ICPs further, the extent of improvement is moderate, and the approach is economically disadvantageous.

In this study, we employed supercritical carbon dioxide (scCO2) treatment under varying conditions: low-pressure treatment at 30 MPa and high temperature at 80°C (LPHT group) and high-pressure treatment at 60 MPa and low temperature at 50°C (HPLT group) for nanocellulose isolation. The scCO2 treatment resulted in smaller particle sizes and enhanced crystallinity. Notably, HPLT exhibited superior efficiency compared to LPHT treatment. Utilizing temperatures and pressures above the critical point effectively penetrated natural fibers, reducing nanocellulose particle sizes. Moreover, high-pressure and low-temperature nanocellulose demonstrated the highest crystallinity and negative zeta potential values (78.2% and –32.4±4.01 mV), surpassing those of the low-pressure and high-temperature group (77.9% and 26.0±2.34 mV) and control (77.3% and 25.9±3.13 mV). The concentration of nanocellulose significantly impacted the porosity, pore size, and water absorption of the bioaerogel scaffolds, indicating the potential for sustainable and environmentally friendly approaches in material fabrication for diverse applications.

Screw extruders as continuous flow reactors allow the synthesis of new polymers, preparation of polymer blends and composites, and modification or functionalization of commercially available polymers. Literature data shows that the twin screw extrusion is the most popular solution used for this purpose. In contrast, the number of scientific papers on alternative methods, such as multi-screw extruders, is somewhat limited. This paper is the first review of the application of planetary roller extruders in the compounding and reactive processing of polymer blends and composites. To fill current knowledge gaps, we discuss the advantages and disadvantages of planetary roller extruders compared to other screw extruders. Moreover, we summarize recent advances in planetary roller extrusion in producing thermal sensitive and biodegradable polymeric materials, rubber compounds, materials for 3D printing, or plastics and rubber recycling. This work also proposes the possible scenarios for further sustainable development of polymer blends and composites using planetary roller extruders.

The proliferation of flexible electronics has entirely transformed the field of antenna design and paved the door for cutting-edge uses in communication, sensing, and other areas. The present research lends a succinct overview of the intriguing advancements in flexible antenna technology, with specific emphasis on the implementation of polymer substrates. As we refer to poly-flex antennas in this article, they stand for the incorporation of polymer substrates in antenna design. Polymer substrates are the optimum candidate for flexible antenna applications as they have specific advantages, including being lightweight, conformable, and inexpensive. The main features of poly-flex antennas, such as their design concepts, fabrication processes, and performance characteristics, are being explored in this proposed article. We delve into the wide variety of polymer substrates that are appropriate for antennas, taking into account their dielectric characteristics, flexibility, and environmental resistance. Their dielectric characterization, bending effects, challenges, and future prospects of this burgeoning field are also addressed. We conclude by emphasizing the immense potential of poly-flex-antennas to shape the future of wireless communication and sensing systems, and how the adoption of polymer substrates is driving innovation in antenna engineering.

Biodegradable porous poly(ε-caprolactone)-poly(trimethylene carbonate)-poly(ε-caprolactone) triblock copolymers (PCL-b-PTMC-b-PCL) were synthesized by sequentεial polymerization of trimethylene carbonate (TMC) and ε-caprolactone (CL), and novel composites of PCL-b-PTMC-b-PCL with different amounts of nano-apatite (nAp) were prepared. This PTMC-based polymer matrix, which does not degrade into acidic compounds, together with the nanometer-sized apatite, which influences cell behavior, is an ideal bone regenerative material. Solvent casting these composites from chloroform solutions yielded solid films with excellent handling properties. The E-modulus of the nano-composite materials increases with nAp content, while toughness, tensile strength and elongation at break decrease. Using EC as solvent, porous composite films of PCL-b-PTMC-b-PCL and nAp could readily be prepared. The composites in EC were processed into form-stable designed tissue engineering scaffolds by 3D printing at relatively mild conditions. Besides the pore network structure with pores of 530 to 620 μm which corresponded to the design, smaller pores of 5–30 μm (due to EC crystallization) and even smaller ones of 200–500 nm (resulting from liquid-liquid exchange upon extraction of the solvent in the polymer rich phase) were observed in the printed composite scaffolds.

Seaweed from macroalgae and cellulose from nonwood materials have gained attention in various fields. This study explores how seaweed and cellulose nanofibers (CNF) interact to form 3D networks in composite bioaerogels. The ratio of CNF and seaweed was varied to see how it affects the aerogel’s inside and its properties. The observations show that the biocomposite aerogel is more rigid and shrinks less than using a single biopolymer. The CNF aerogel has a fine, thin network structure, and the seaweed aerogel has a thin sheet structure. The biocomposite aerogel combines both a fine network and a thin sheet structure. The composite aerogel’s mechanical properties are significantly influenced by seaweed composition. The introduction of CNF increases elasticity, while seaweed enhances firmness. Generated computer modelling revealed that the abundant hydroxyl groups in CNF facilitated the formation of intermolecular bonds with seaweed. The bonding led to increased adhesion and entanglement between biopolymers, consequently enhancing elasticity and establishing a stable intermolecular interaction. The 3D X-ray imaging model shows that the skeletal framework primarily consists of seaweed biopolymer, with CNF serving to reinforce this structure thus enhancing the mechanical properties and robustness of the composite bioaerogels.

Silicone rubber magnetorheological elastomers (SR-MREs) are increasingly recognized for their resilience in marine conditions, offering prolonged service life and durability. This study evaluates the one-month durability of silicone rubber magnetorheological elastomers (SR-MREs) under seawater conditions. Results revealed a 6% reduction in hardness and an 8% decrease in Young’s modulus compared to unimmersed samples. Morphological and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) analyses supported these findings, revealing surface defects and chemical bonding changes. The immersed SR-MRE displayed a notable 250% increase in elongation at break, highlighting enhanced elasticity. Rheological properties revealed complex mechanical behavior, with an initial increase in storage modulus from 0.25 to 0.38 MPa in the presence of a magnetic field, followed by a gradual decrease to 0.15 MPa at 0 A and 0.52 Mpa at 5 A with strain. Additionally, this study proposes an illustrative mechanism to elucidate the relationship between seawater elements and SR-MRE behavior, enhancing our understanding of its mechanical properties and degradation in marine environments, thus highlighting SR-MRE’s potential as a durable material compared to traditional rubber composites.

Blown films from ethylene-propylene random copolymers (C2C3-RACOs) are used in many packaging applications today, constituting a major fraction of both mono- and multilayer packaging film constructions. Combining high processing speed and output with good mechanical and optical performance, mostly high toughness and low haze, requires understanding the structure-property-processing relations. To improve said understanding for C2C3-RACO blown films, two commercial grades with a nearly identical C2 content of ~4.4 wt% and identical melt flow rate (MFR) but different nucleation were selected. These were tested in a processing study, varying melt temperature, blow-up ratio (BUR) and neck length. The film structure was analysed by wide angle X-ray scattering (WAXS) and atomic force microscopy (AFM), and the performance by standard mechanical and optical tests. Variation of film crystallinity was found to be in the range of 62 to 65%, much smaller than in earlier cast film studies on comparable polymers. The tensile modulus is the only performance parameter for which a general positive correlation to crystallinity can be found, blown films being about 50% stiffer than the softest cast films of a comparable polymer. Ductility and toughness are enhanced by higher orientation, resulting from higher BUR and/or higher neck length. For transparency and haze, low surface roughness is decisive at comparable crystallinity, which can be achieved by increasing melt temperature.

In this research, a straightforward template method was utilized to fabricate a superhydrophilic ethylene-vinyl acetate copolymer (EVA)/nitrile-butadiene rubber (NBR) thermoplastic vulcanizate (TPV) surface where the paper sheet was used as template. Organic modified montmorillonite (OMMT) powder was introduced in order to improve the superhydrophilic response rate of the TPV surface. Investigations were conducted to research the durability and the self-cleaning behavior of the TPV surface, as well as to explore its potential application in the separation of oil-water and oil-oil mixtures. Experimental results demonstrated that the EVA/NBR/OMMT TPV (mass ratio 20/80/7) surface molded with No. 1000 paper sheet exhibited the excellent superhydrophilic property, which could achieve a contact angle of 0.0° within 5.5 s and had a surface energy of 35.6 mN·m–1. The superhydrophilic surface displayed the remarkable durability and the evident self-cleaning behavior; moreover, it could exhibit the significant difference in the critical pressure data for various liquids, suggesting the promising application in the field of oil-water and oil-oil separation.

This work reported a practical approach to turning conventional natural rubber (NR) into a thermally healable rubber. 4-vinylbenzyl chloride was first polymerized in the NR latex to yield graft copolymers of NR and poly(vinylbenzyl chloride), NR-g-PVBC. The cutting and rejoining process was used to study the healing ability of latex film. The healing behavior was observed after the reassembled film was heated at 100 °C for 1 h and then allowed to heal continuously at room temperature (RT). The healed film displayed a 58.44% regain of the tensile strength (4.57 MPa) after being allowed to recover at RT for 72 h. Additionally, the chloromethyl moieties in the NR-g-PVBC could be converted into quaternary ammonium (QA) groups by reaction with trimethylamine, producing the quaternized NR-g-PVBC (NR-g-QPVBC). Ionic crosslinking of the NR-g-QPVBC film was achieved by incorporating sodium tripolyphosphate (STPP). The latex film had a tensile strength of 15.32 MPa and could withstand a strain of 868% when ionically cured with 2 phr of STPP. After the healing process, the cured film showed a healing efficiency of 49.67% in tensile strength (7.61 MPa). Furthermore, a suturing test was performed to investigate the feasibility of developing a suture training pad from the corresponding cured film. The film’s ability to heal with heat assistance was its significant practical advantage, enhancing its realism and mimicking the healing process in human skin.

This study focuses on producing polyurethane dispersion (PUD)/carboxylated nitrile butadiene rubber (XNBR) blends with different types of crosslinkers without both accelerators and sulphur. Two types of crosslinkers: epoxide crosslinker and organo-modified siloxane, are introduced in the PUD/XNBR (blending ratio of 80:20). The zeta potential and particle size of the PUD/XNBR blends were determined using a dynamic light-scattering nanoparticle analyser. The chemical interaction and surface roughness of the PUD/XNBR blends were evaluated using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). The zeta potential and particle size of the PUD were influenced by XNBR blending and the types of crosslinkers. FTIR observations indicate that the XNBR and the crosslinkers facilitated intermolecular hydrogen bonding and different extents of ordered hydrogen bonding. A higher degree of ordered hydrogen bonding can be associated with a higher surface roughness of the PUD/XNBR blends. Nevertheless, the hybrid crosslinkers can be used to achieve reasonable surface roughness for the easier donning of latex gloves. The research findings can be applied to design glove products with desirable surface roughness and intermolecular bonding.

In order to improve the impact toughness of polyamide 1012 (PA1012) by reducing the amount of hydrogen bonding resulting from PA1012 itself, 3-pentadecylphenol (PDP) was considered to be added into PA1012 using melting extrusion. The hydrogen bonding interaction between PA1012 and PDP was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The effects of PDP on the crystallization, melting process, and mechanical behavior of PA1012 were tested in detail. The results show that the PDP can reduce the temperature of PA1012 crystallization and melting but it can significantly improve elongation at break and impact toughness. The notched impact strength of the PA1012/PDP composites containing 20 wt% PDP reached to 70.6 kJ·m–2, which is about seven times that of the neat PA1012. The effects of PDP on PA1012 properties is ascribed to hydrogen bonding interaction between hydrogen bonding between phenol hydroxyl groups and amino groups on PA1012 chains. The deduction was also verified by adding acetylated 3-pentadecylphenol (APDP) to modify PA1012. It is believed the research will open up new prospects for the wide application of PA1012 toughening.

The paper presents the photomechanical effect generated in new azo side-chain polyimides synthesized through a post-functionalization strategy involving the Mitsunobu reaction. Prepared azo polyimide foils were irradiated by a 405 nm diode-laser beam (intensity, I = 100 mW/cm2; polarization, Eǀǀx) for the generation of the photomechanical effect. Despite the low content of azo chromophore (substitution of the hydroxyl group was in the range of 7–35%) and thick cantilevers (thickness ~35 μm), bending angles were in the range of 30–40°. Thermal unbending was not observed for 12 months after turning off the excitation light. Our investigation showed that, despite the low content of azo chromophore, it is possible to achieve photodeformation under polarized light. To the best of our knowledge, this is the first example of the photomechanical response of azo pyridine polymers.

Glyceryl lactate (GlyLA) was synthesized through the esterification of glycerol (Gly) and lactic acid (LA) to plasticize whey protein concentrate (WPC) films with three different ratios of WPC to plasticizer (85, 90, and 100% w/w). LA was also introduced as a new plasticizer of whey protein films and compared in similar contents. Gly-plasticized films were also used as control groups. The synthesized GlyLA, including compatible esterification degree with WPC, was characterized by Fourier transform infrared Spectroscopy (FTIR) and hydrogen nuclear magnetic resonance spectroscopy (H-NMR) analyses. Then, the plasticizing effect of different types of plasticizers on the optical, thermal, mechanical, and water resistivity properties of the prepared films was evaluated. FTIR in attenuated total reflectance (ATR), Differential Scanning Calorimetry (DSC), tensile measurements, and cup method were also employed to examine the molecular structure, transition temperatures, mechanical resistivity, and water vapor permeability (WVP) of the modified films. The results showed a lower glasstransition temperature (Tg) and better ductility. By Increasing plasticizer content, solubility and WVP were increased in all groups. Furthermore, WPC-based films plasticized with 80 or 90% w/w of LA and GlyLA exhibited not only higher tensile strength and flexibility but also remarkably lower WVP than Gly plasticized films, turning them into potential alternatives for application as food packaging.

Extensive research and practical applications have been conducted within the biomaterials domain, focusing on polylactic acid (PLA) based composite. These composites have been explored for their favorable attributes, such as excellent processability, biodegradability, and bioactivity properties, but still lack mechanical properties. In this work, PLA-based nanocomposites were prepared by incorporating hydroxyapatite (HA) and graphene oxide (GO) via melt mixing (extruder). Filaments were obtained to develop scaffolds through 3D printing, utilizing the fused deposition method (FDM). The GO was produced using Hummer’s method and characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Raman Spectroscopy. The composites were analyzed using Fourier-transform infrared spectroscopy (FTIR), molecular weight, contact angle measurements, and thermal, mechanical, and rheological analysis. Adding only 0.05 wt% of GO to both PLA and PLA/HA resulted in enhancements in mechanical properties, particularly tensile strength, and significantly modified the surface properties of the materials studied. Specifically, formulation involving PLA/HA/GO was the only one to exhibit rheological properties compatible with the scaffold production process via FDM. These specific formulations were also investigated regarding cytotoxicity, and the presence of GO induces good cytocompatibility in mouse osteoblast cells (MC3T3). These results suggest that FDM technology can be used to fabricate higher-performance (mechanical and biological) scaffolds for tissue engineering.

The augmented demand for sustainable nanocomposites has paved the way to explore naturally derived materials. Nanocellulose, with its bountiful sources and inherent properties, ranks top in the list of biofillers with a perspective of reducing the carbon footprint. A systematic study is required to understand the reinforcing effect of various types of nanocellulose. In the present work, we selected three types of nanocellulose, i.e., cellulose nanocrystal (CNC), cellulose nanofiber (CNF) and microfibrillated cellulose (MFC), to investigate the effect of geometrical structure on the properties of unvulcanized natural rubber (NR). Incorporating these fillers improved the tensile strength and modulus of natural rubber films significantly through reinforcement via filler network structure. The reinforcing effect of CNF was found to be higher compared to CNC and MFC, where an increase of 3.85 MPa in tensile strength from the neat sample was obtained. More uniform dispersion was evident through transmission electron microscopy, atomic force microscopy and Raman imaging for CNF in the rubber matrix. The structural properties were determined using Raman spectra and X-ray diffraction. The rheological studies revealed a good interaction between filler and NR. The work presented comprehensively compares different types of nanocellulose as reinforcing filler in NR matrix, which will help the researchers select an ideal type for their specific application and, thus, the proper usage of renewable resources, leading to sustainability and a circular economy.

As a key component of lithium-ion batteries, a separator with excellent electrolyte wettability and good thermal stability has an important impact on the overall performance of lithium-ion batteries. Herein, a PVDF/sepiolite electrospun layer was coated on one side of the PP separator via electrospinning technology to prepare the composite separator (xMS-PVDF@PP) with sepiolite nanofibers modified with vinyltriethoxysilane (VTES) to ameliorate their dispersibility and compatibility with PVDF polymer matrix. The effect of modified sepiolite addition amounts on the physical and electrochemical properties of composite separator was intensively studied. It is found that the as-prepared xMS-PVDF@PP composite separator displays enhanced porosity, electrolyte uptake, thermal stability and Li+ ion transport kinetics than pristine PP separator. Specifically, Li|LiFePO4 battery with 20MS-PVDF@PP as separator shows the best rate and cycling performance, with a specific discharge capacity of 115.3 mAh·g–1 at 10C rate and a capacity retention rate of 97.06% after 200 cycles at 1C rate. The sepiolite in the electrospun layer can immobilize PF6– anion to facilitate the uniform distribution of Li+ ions and then inhibit the lithium dendrite growth, as well as absorb HF to alleviate Fe2+ dissolution from LiFePO4 cathode, thereby further improving the electrochemical performance of LiFePO4 battery.

Thermoplastic elastomer gels based on styrenic triblock copolymers have been increasingly used as dielectric elastomers, particularly due to the possibility of tailoring their properties based on their composition. However, these materials have a low relative permittivity, primarily attributed to their low dipole moment. Consequently, this characteristic poses a challenge for their application as dielectric elastomers. In this work, we aim to assess the impact of adding kraft lignin on the dielectric properties of thermoplastic elastomer gels. Additionally, we investigate the effects of kraft lignin dispersion on their viscoelastic and mechanical properties. For this purpose, we used two types of kraft lignin: acidic and alkaline (ac-KL and alk-KL). The alk-KL demonstrated higher dispersibility in the polymer, mainly attributed to the deprotonation of its structure during its production process. As a result, the dielectric elastomer with alk-KL showed a 50% increase in relative permittivity compared to the pristine polymer without compromising its mechanical and viscoelastic properties. Moreover, these samples demonstrated a greater actuation strain capability in response to an electrical stimulus. Thus, the incorporation of lignin demonstrates promise as a valuable reinforcement in the development of advanced dielectric materials, enhancing their electro-mechanical performance.

Dibutyl phosphate-bound natural rubber (DBNR) was prepared by reacting epoxidized natural rubber with 20 mol% (ENR-20) with dibutyl phosphate in a latex medium. Fourier transform infrared spectroscopy (FTIR) was used to confirm the molecular structures of ENR-20 and DBNR and to quantify the epoxide contents. The shear flows and thermal properties of DBNR were then characterized and compared with ENR-20 and natural rubber (NR). The DBNR exhibited the lowest viscosity curves, but it depicted the highest glass transition temperature (Tg) and residue from thermogravimetric evaluation, indicating higher thermal resistance. Subsequently, different NR/DBNR blend ratios were compounded, with and without flame resistance additives, compared with unmodified NR and chloroprene rubber (CR) compounds. We found that all natural rubber compounds exhibited reversion behavior due to the breakage of newly formed sulfidic bonds. However, chloroprene rubber showed marching cured curves, as evidenced by the increasing torque with prolonged testing time. Additionally, antimony trioxide retarded the curing reaction of NR, while tris(2-ethylhexyl) phosphate accelerated it. Therefore, the combination of these additives synergists with the intrinsic flame retardant properties of DBNR. The study revealed that the burning rate of NR/DBNR blends, exhibited very high flame resistance capability compared to gum NR and NR compounded with flame resistance additives.

Polymer-based hydrogels are hydrophilic polymer networks with a remarkable capacity to absorb substantial amounts of water and biological fluids, rendering them highly attractive for drug delivery applications. The COVID-19 pandemic has acted as a catalyst for research and innovation in the realm of polymer-based hydrogels for drug delivery, with a particular emphasis on antiviral therapeutics, vaccines, diagnostics, and precision delivery to the respiratory system. The distinctive attributes of hydrogels, such as their biocompatibility, customizable drug release profiles, and ease of functionalization, establish them as versatile platforms for the development of advanced drug delivery systems to combat not only COVID-19 but also a spectrum of other infectious diseases. This study is dedicated to scruti-nizing and evaluating the characteristics of polymer-based hydrogels employed in drug delivery for the treatment of diseases associated with the SARS-CoV-2 virus. Furthermore, the investigation introduces a novel classification system for polymer-based hydrogels deployed in drug delivery for SARS-CoV-2-related diseases. Additionally, the paper provides an up-to-date evaluation of the latest developed hydrogels utilized in drug delivery for the treatment of dis-eases linked to the SARS-CoV-2 virus, based on research conducted through the recent months of 2023.

High-performance polymers are extensively used in various applications undergoing long-term cyclic loadings. The deformation behaviour of an amorphous thermoset epoxy resin undergoing cyclic compressive loading is investigated for a range of applied deformation levels. The measurements indicate significant hysteresis upon repeated loading and unloading cycles with progressive accumulation of plastic strain. Cyclic damage leads to a reduction of the stress needed to reach the peak strain per cycle, while cyclic stiffening corresponding to an increase of elastic modulus with increasing number of cycles is observed, attributed to chain orientation effects. The dissipated energy asymptotically decreases to zero under strain-controlled cycling conditions. Interestingly, when monotonically loaded after cycling, the epoxy exhibits an increase in yield strength. This ‘re-yield’ stress level is closely related to the selected value of the peak (unloading) strain level and increases with increasing number of loading cycles.

The present study aimed to prepare prevulcanized latex from modified natural rubber (NR) latex, graft copolymers of natural rubber and poly(vinylbenzyl chloride), NR-g-PVBC. The prevulcanized latex was prepared by heating NR-g-PVBC latex in the presence of adipic acid dihydrazide (ADH). The study showed that the tensile strength of the NR-g-PVBC films with ADH was significantly higher than that without ADH. Interactions of NR-g-PVBC with ADH were further investigated using X-ray photoelectron spectroscopy (XPS). Higher storage modulus (E′) in the rubbery plateau region was also observed for the films with ADH than that without ADH. These results corroborated that the crosslinking reaction occurred in the film with the addition of ADH. It was found that the optimal prevulcanization time was 20 min at 55 °C. After that, the effect of storage on the tensile properties of the prevulcanized latex was studied. Atomic force microscopy (AFM) analysis was performed to follow changes in the surface morphology of films obtained from the prevulcanized latex. A zeta potential value of –37.83 was observed for the prevulcanized latex after being stored for 60 days. Therefore, the present study demonstrated that grafting poly(vinylbenzyl chloride) onto NR particles offered an opportunity to prepare a new type of prevulcanized latex. This new system was accelerator-free and zinc-free, considered more environment-friendly than a sulfur-prevulcanization system.

A set of linear Fischer-Tropsch (FT) waxes were oxidized to various degrees by utilizing an ozonolysis method. These waxes were comprehensively characterized in terms of their chemical composition, thermal behaviour, molecular weight distributions, and overall polarity using various analytical techniques, including Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), high temperature size exclusion chromatography (HT-SEC) along with normal and reverse-phase high temperature solvent gradient interaction chromatography (HT-SGIC). Application-based studies were performed by evaluating the behaviour of these waxes in unplasticized polyvinyl chloride (uPVC) formulations. Analyses included hot melt mixing, single screw extrusion, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), and torque rheometry. Through a combination of these techniques, the lubrication mechanism of these waxes could be explained by the Rabinovitch model. It was found that a combination of molecular size and degree of polarity play a vital role in the migration of the waxes and therefore ultimately impacts the fusion behaviour of the overall polyvinyl chloride (PVC) formulation. Results indicate that fusion times can greatly be altered when using oxidised waxes, and this could be promising for the development of multifunctional lubricant systems.

In a blend of poly(lactic acid) (PLA) and thermoplastic starch (TPS), a 15% load of hemp seed lignocellulosic filler (HF) was incorporated. Additionally, separate petrochemical-based compatibilizers, such as dicumyl peroxide (DCM) and benzoyl peroxide (LRL), as well as a bio-based compatibilizer, maleinized hemp seed oil (MHO), were introduced. Adding HF to the PLA/TPS blend reduced tensile mechanical properties due to the stress concentration phenomenon arising from the lack of interaction between components, yielding a more brittle material. This issue was mitigated by adding compatibilizers, notably the incorporation of MHO into the PLA/TPS/HF blend this increased elongation at break by enhancing compatibility among the blend components and providing a plasticizing effect. Moreover, regarding thermal properties, it was observed that the inclusion of HF led to a decrease in the glass transition temperature (Tg), cold crystallization temperature (Tcc), and melting temperature (Tm). Conversely, adding MHO to this blend increased all these values compared to the PLA/TPS/HF mixture, attributed to the plasticizing effect imparted by the modified oil. Additionally, following fracture in Charpy impact testing, the samples were subjected to field emission scanning electron microscopy (FESEM) analysis to examine the fractured surface of the various samples.

The increase in environmental consciousness and waste-to-wealth concepts in the automobile sector has led to the use of natural fibers in desirable quantities. The current study deals with the extraction, treatment, and utilization of Lycium ferocissimum stem fibers for friction composite in braking applications. The fibers of Lycium ferocissimum were extracted through manual retting and subsequently treated with benzoyl chloride. Both the benzoyl chloride treated and untreated fibers of Lycium ferocissimum were employed as reinforcements in the formulation of a friction composite, following the standard practices of the industry, and the comparison was made using commercially available friction composite. The developed friction composites were tested for original equipment manufacturer quality requirements following industrial Standards. The friction composite’s tribological behavior was analyzed using the Chase test following the Society of Automotive Engineers standards. The worn surface characteristics were analyzed using scanning electron microscope. The test results elucidated that benzoyl chloride-treated Lycium ferocissimum fibers-based friction composites showed good frictional properties with better wear resistance compared to others, having a weight loss of 5.4%.

Environment-responsive hydrogels are environmentally friendly polymeric materials that rapidly respond to their environment by changing their volume or strength when the external environment, such as temperature, pH, light, and magnetism, changes. As environment-responsive hydrogels, they are uniquely flexible and sensitive, enabling them to be used in various applications, and are now at the forefront of polymer science research. Scholars have reviewed more environmentresponsive hydrogels in biomedicine, detection sensors, and drug release. We present a detailed description of the reaction mechanism and preparation process of environment-responsive hydrogels, taking temperature-responsive, pH-responsive, and light-responsive hydrogels as examples. Finally, a summary is given at the end: 1) the application of environmentally responsive hydrogels in agriculture, and 2) the problems and future trends of their application in agriculture.

This work reports on the synthesis of non-isocyanate polyurethanes (NIPUs) obtained via the polyaddition of diamines: dimer fatty acid-derived diamine (DFA diamine) or polyether diamine (PPO diamine) with five-membered tri(cyclic carbonate) by a pre-polymerization method. The obtained NIPUs were further chemically modified by polyhedral oligomeric silsesquioxane (POSS) – glycidylisobutyl POSS (1epPOSS). The resulting reinforced composites, containing 5, 10 or 15 wt% 1epPOSS, were characterized in terms of their structure (FTIR, NMR, XRD), microstructure (SEM-EDS) and thermo-mechanical properties (DMA). FTIR confirmed the formation of polyurethanes, and NMR proved the chemical incorporation of 1epPOSS. XRD and SEM-EDS showed a uniform distribution of 1epPOSS in the matrix for low 1epPOSS concentration, with some agglomeration effects depending on the concentration of 1epPOSS. DMA indicated mechanical reinforcement of NIPUs based on DFA diamine. For NIPUs synthesized with PPO diamine, the composite with the highest 1epPOSS loading (15 wt%) exhibited superior mechanical properties in comparison to the pristine matrix, confirmed by both DMA and static stretching test.

A novel adsorbent material for the effective removal of hazardous metal ions from aqueous solutions was developed through modifications to chitosan. The process involved the use of vanillin to create cross-linked chitosan, which was then combined with thiourea-based graphitic carbon nitride (g-C3N4) to form a gel matrix. The resulting composite material was thoroughly characterized using various techniques, including Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractometry. To assess its efficacy, adsorption experiments were conducted to determine the capability of the synthesized compounds to adsorb Cu(II) and Cr(VI) ions. The observed results found that the adsorption process was found to follow pseudo-second-order kinetics and the Langmuir isotherm model. Through thermodynamic studies, it was revealed that the adsorption process was both endothermic and spontaneous in nature. Furthermore, desorption studies confirmed that the material could be regenerated, making it reusable. This characteristic allowed for the effective recovery of the adsorbate species and highlighted the potential for reusing the adsorbent material multiple times.

Composite materials are of increasing interest in aircraft and spacecraft structures, and carbon fiber reinforced polymers (CFRP) have emerged as materials meeting quality standards for structural applications in the aircraft industry. Despite their high mechanical properties, CFRPs are associated with high production costs. Building on recent research by the authors, this paper investigates the use of ply-level hybridization to reduce manufacturing costs while maintaining the mechanical performance of the manufactured material. Focusing on the causes of nonlinear response under off-axis tensile loading, the paper involves cyclic load-unload (LU) tensile tests conducted at off-axis angles of 15°, 30°, and 45° to predict mechanical characteristics and damage evolution. Residual strains are directly extracted from load-unload stress-strain responses. Three distinct methods for estimating cycle modulus are employed and compared for damage variable formulation. The research findings reveal dependencies of both the damage variable and residual strains on the off-axis angle. Furthermore, the method used to assess the modulus during cycling loading significantly influences the damage variable estimation. Encouragingly, the hybrid laminates exhibit reduced internal damage and matrix plasticity compared to reference counterparts, indicating a positive effect on the mechanical performances of hybridized CFRPs in addition to the cost reduction.

In this study, the potential use of nanocrystalline cellulose (CNC) modified epoxy nanocomposite as a matrix is investigated for both glass and carbon fiber-reinforced composites. Various amounts of CNCs (1, 2, 4, and 6 wt%) were added to bisphenol A diglycidyl ether-based epoxy resin (DGEBA), and the optimum CNC loading was determined as 4 wt% in terms of mechanical and thermal properties. Compared to the reference sample containing a neat epoxy matrix with the obtained carbon fiber/CNC-epoxy (CNC/epoxy/CF) and glass fiber/CNC-epoxy (CNC/epoxy/GF) hybrid nanocomposites, significant improvements have been determined in the in-plane shear modulus and strength, and flexural modulus, respectively. The mechanical properties improvements of CNC/epoxy/CF hybrid composites are approximately 0.9% higher than the CNC/epoxy/GF hybrid composites. Additionally, the distribution of CNC in hybrid nanocomposites is also investigated by scanning and transmission electron microscopies. It is noted that the homogenous dispersion of CNCs in the epoxy matrix and their diameters varied from 10 to 100 nm are detected at higher magnification.

An environmental pollution problem is caused in part by packaging materials made from non-biodegradable synthetic polymers derived from petroleum. In this study, eco-friendly biofoams derived from natural rubber (NR) latex and rice starch (RS) were manufactured on a laboratory scale using the Dunlop process. Rice starch content was varied from 0 to 50 phr. The morphological, thermal, physical, mechanical, and biodegradability properties of the NR/RS biocomposite foams were characterized. Scanning electron microscopy (SEM) was used to assess the morphology of the foam cells. Dynamic mechanical thermal analysis (DMTA) and Thermogravimetric analysis (TGA) were used to investigate the thermal characteristics. When RS was present, it was discovered that the biocomposite foams had decreased thermal stability and enhanced biodegradability. Introducing RS into the NR/RS biocomposite foams also decreased tensile strength, elongation at break, and rebound resilience but increased the 100% modulus, hardness, compression force deflection (CFD), and compression set. The NR/RS biocomposite foams better preserved the banana fruit than the absence of foam, with lower ethylene accumulation, lower total soluble solids (TSS), higher pulp firmness, and good color preservation. This demonstrated that these NR/RS biocomposite foams helped to preserve banana fruit quality during storage and could be used in sustainable packaging applications.

The elaboration of potent delivery systems for peptides/proteins is still a challenge but is increasingly needed in advanced therapy. In the present research, we have developed a nanoencapsulation system for peptides/proteins, which is suitable for the delivery of hydrophilic bioactive compounds. The preparation method combines the advantageous properties of reverse nanoemulsion and nanoprecipitation, resulting in the formation of nanoparticles in the size range of 350–500 nm. The polymeric coating composed of polycaprolactone allows chemical functionalization and protection while the inner microenvironment (containing 1-decanoyl-rac-glycerol and N,N-dimethyldodecylamine N-oxide surfactants) provides aqueous surrounding for the active with structural fidelity. Hen egg white lysozyme and β-lactoglobulin were successfully encapsulated, achieving protein contents of 10–60 μg/mg and encapsulation efficiencies ranging from 5–50% depending on the protein type and loading concentration. In vitro release measurement showed a biphasic sustained release profile of both proteins in the time range of one month. In vitro cytotoxicity investigation of protein-loaded nanoparticles exhibited good cell viability (above 95% at the highest treatment concentration of 0.3 mg/ml). The encapsulated membrane-active peptides have shown improved bioactivity.

A series of environmentally friendly non-isocyanate polyurethanes (NIPUs) was synthesized through a polycondensation reaction of as-synthesized semi-bio-based bis-cyclic carbonate with diamine derivatives. The synthesis of biscyclic carbonate was realized, for the first time, from 1-thioglycerol and polyethylene glycol diacrylate via thiol-ene click and transcarbonation reaction, respectively. The impacts of using different diamine derivatives on the chemical structural, mechanical properties, thermal stability, and surface wettability of the NIPUs were determined. It was found that the NIPU containing fatty acid-based diamine decomposed at a lower temperature than that of other polymers. Besides, it demonstrated a lower Young’s modulus and a higher tensile strain at break, possibly due to its four-branched structure and greater flexibility. Meanwhile, the NIPU prepared with p-xylylenediamine provided the highest decomposition temperature, owing to an aromatic moiety in the polymer’s backbone, which improved its stiffness and thermal stability. Furthermore, it was understood that the NIPU containing diamino-N-methyldipropyl-amine exhibited a higher Young’s modulus and a lower tensile strain at break, as it had a nitrogen atom in its structure and a trigonal pyramidal configuration with the highest density of hydrogen bonds between polymer chains. Most of the developed NIPUs displayed hydrophobic surface properties, offering promising alternatives to isocyanate-based coating materials.

The global concern over zinc leaching into aquatic ecosystems has led researchers to seek ways to reduce zinc oxide (ZnO) content in rubber products. Conventional microsized ZnO, commonly used in the rubber industry, poses dispersion challenges due to its hydrophilic nature and micron size within the hydrophobic rubber matrix. Therefore, higher amounts of ZnO are added, elevating the risk to aquatic life. A promising alternative involves using highly dispersible ZnO with active zinc (Zn) centers instead of conventional ZnO. Another approach includes incorporating ZnO-anchored silica particles into the rubber matrix, which requires additional ex-situ fabrication. This study presents an innovative method where ZnO-anchored silica is generated in situ during the blending of styrene-butadiene rubber/natural rubber (SBR/NR). The study also evaluates the effectiveness of active, nano-sized, and octylamine-modified ZnO as activators compared to conventional ZnO, by introducing silica filler, octylamine-modified and high surface area ZnO anchor onto the silica surface, forming Si–O–Zn covalent bonds. This protective layer reduces filler aggregation and the Payne effect. Even with 60% less usage, these activators in the SBR/NR blend significantly enhance tensile strength (31.27%) and elongation at break (49.13%) compared to conventional ZnO. These results point towards the possibility of a cost-effective and sustainable replacement for conventional ZnO.

In this study, we produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibrous mats via solution blow spinning (SBS) and evaluated their microstructural properties. We propose here the utilization of the theoretical estimative of relative viscosity (RV) as an independent variable in a statistical design of experiments (DoE) to account for the polymer’s molecular weight (Mw) effect on the determination of the diameter and morphology of the fibers. The RV of the solution (42.3・103–287.4・103) and air pressure – AP (70–140 kPa) were varied. The analysis of variance (ANOVA) indicated that the increase in RV favored an increment in fiber size and resistance to alignment. Higher AP produced aligned and thinner fibers with higher crystallinity. The spinnability regions were determined based on the estimated RV of the PHBV solutions and the AP levels. Fibers were formed at 70 kPa from solutions with RV ranging from 10・103 to 106, while at 140 kPa, from 42・103 to 106. Nanofibers were produced from less viscous solutions (RV = 42.3・103–124.4・103), while microfibers were produced from solutions with RV = 287.4・103. The developed ANOVA model predicted with good accuracy (R2adj. = 0.96) the average diameter of the PHBV fibers produced from the SBS technique using polymers with distinct Mw values, including those available in the literature data.

Silicone foam (SF) is a porous silicone rubber with a lower density, higher elasticity, and good thermal stability. In this work, we selected aluminum spheres and carbon fiber (CF) as thermally conductive fillers to prepare hybrid SF. After optimization, we found that Al and CF hybrid SF (Al-CF-SF) has a higher thermal conductivity (1.37 W·m–1·K–1) than the single-filler filled SF (CF-SF, 1.2 W·m–1·K–1 or Al-SF, 0.52 W·m–1·K–1) under the same filling amount of 60 wt%. The finite element simulation was used further to explore the thermal conductive mechanism of the hybrid SF. Meanwhile, the compressive and tensile modulus of the material (CF-SF) was increased to 10.8 and 3.3 MPa compared with pure SF, respectively, and the mechanical properties were improved. In addition, infrared thermography further demonstrated that Al-CF-SF has a faster heat transfer rate under relaxation and applied pressure.

Adhesives have been widely applied in various fields. However, most industrial adhesives contain organic solvents, which are toxic and difficult to clean after use. Importantly, most adhesives are used in a relatively small temperature range (0–50 °C), which is due to the fragmentation of the morphology and properties of supramolecular polymer gels at low temperatures. Most of the supramolecular adhesives need to be heated during the bonding process, which cannot meet the requirements of low-temperature adhesion in daily life and industry. In this study, based on the concept of using deep eutectic solvents (DESs) as a platform, cyclodextrin (β-CD) and carboxyl terminated hyperbranched polyester (DCHP) were used to prepare solvent-free supramolecular polymer gel (CD-DCHP), which was non-toxic and easy to clean. Due to the joint action of deep eutectic solvent and supramolecular polymer structure, CD-DCHP showed excellent mechanical properties, super strong adhesion (up to 4.55 MPa on glass surface), and excellent low-temperature performance (up to 1.64 MPa at –60 °C). This supramolecular polymer gel also showed excellent tolerance to acids, alkalis, and various organic solvents. It greatly expanded the application of DES and provided a new approach to the development of supramolecular adhesives.

We have performed shrinkage restraint force measurements on three shape memory polymers of polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and a blend of the two at a range of temperatures. Observations are made of the change in stress during temperature rise, hold and cooling. All materials show an increase in stress during rise and hold, but on cooling, the three materials behave differently; the PET shows a drop in stress, the PMMA a rise and the blend a much smaller rise. This behaviour correlates with the reversible thermal dimensional change below the shrinkage threshold temperature; the expansion coefficients are negative for PET, positive for PMMA and positive at a lower order of magnitude for the blend. We model the behaviour by supposing that the shrinkage forces are created by prestressed strains effective at long range within a matrix of shorter chains effective at short range. The total stress is the sum of the shrinkage stress and the thermal stress in the matrix. The drops in stress on cooling are modelled using an elastic analysis based on measured elastic moduli and thermal expansion coefficients. For the blend, downward jumps in temperature produce small transient increases in the total stress, leaving it effectively unchanged. This phenomenon and the results of the elastic model for the stress drops imply that the shrinkage stress from the long-range chain network is largely unaffected by the temperature change and so is not entropic.

The present work describes, for the first time, the chemical modification and characterization of epoxy resins derived from Brazil nut oil (BNO). The development of a bio-based resin has been carried out by chemically modifying BNO, resulting in epoxidized Brazil nut oil (EBNO). Moreover, through a maleinization process, a crosslinker based on maleinized Brazil nut oil (MBNO) has been employed. Analysis using techniques like iodine value (IV) and oxirane oxygen content (Oo) indicate successful chemical modification. FTIR analysis confirms the presence of reactive functional groups in both EBNO and MBNO, which are responsible for resin crosslinking. Mechanical testing of the different bio-resins developed shows that, in the cured resins, flexural strength and modulus decrease with increasing MBNO content, indicating improved flexibility due to the introduction of MBNO as a crosslinker. Thermal analysis using differential scanning calorimetry (DSC) reveals exothermic peaks corresponding to resin curing appearing at progressively lower temperatures. Therefore, this study successfully modifies BNO and demonstrates its effectiveness as a precursor to develop bio-based epoxy resins. The resulting resins exhibit improved ductile and thermal properties, making them suitable for various applications requiring low mechanical stresses.

Polyvinyl alcohol (PVA) is a type of water-soluble polymer that is a candidate for ‘sea’ polymer to prepare seaisland fibers in industry. In this study, two types of polyols (sorbitol ether and neopentyl glycol) were mixed in different proportions and used to prepare thermoplastic PVA (TPVA) as a compound plasticizer. When the plasticizer was introduced, a blue shift occurred on the characteristic band of hydroxyl in the Fourier transform infrared spectroscopy (FTIR) pattern. The melting temperature (Tm) of the corresponding TPVA decreased, and their initial decomposition temperature (Td) increased to some degree. The addition of compound plasticizer made PVA show an improved Td up to 273.1 °C. Moreover, it led to an increment of the melting flow index and improved the resistance to oxidation at a temperature higher than 200°C. The increased spinnability enabled TPVA in PVA-PLA sea-island fiber making. PLA superfine fibers were obtained after splitting in water at 95 °C for just 3 min.

AbstractIn graphene electronics applications, in order to obtain the size and pattern required for the device, it is often necessary to photolithography the graphene after growth, resulting in contamination of graphene by the photoresist which have doping effect. Therefore, in order to avoid this effect, this article focused on directly grown patterned graphene. Based on atmospheric pressure chemical vapour deposition (APCVD) technology, patterned graphene was successfully grown on SiO2/Si by metal proximity catalytic effect. The patterned graphene was characterized by Raman spectroscopy and optical microscope. The effects of parameters such as gas flow, growth temperature, and growth time on the growth of patterned graphene were explored, and the best results were obtained. Metal copper and cobalt thin films were used for assisted catalysis, respectively, and the mechanism of metal proximity catalysis was explored. The experimental results showed that proximity catalysis is a catalytic growth mechanism based on surface diffusion. The growth method avoids using photolithography to make patterns, and can grow patterned graphene on insulating substrates or semiconductors in one step, which is of great significance for making patterned graphene and applying them to semiconductor devices.