Polymer Blends Research Articles

Multiple‐Shape Memory Polymer Blends Formed by Massive Formation of Interphases via Ultrahigh Plastic Deformation

AbstractThe development of advanced shape memory polymers (SMPs) requires the creation of approaches that offer the possibility of forming different temporal shapes as well as changing the corresponding shape memory transition temperatures. A distinctive feature of ultrahigh plastic deformation methods is the possibility of producing polymer blends with a maximum content of interface to form a single broad thermal transition. This can be an attractive way to produce multi‐SMPs based on a simple processing technique. Two polymer pairs—glycol‐modified polyethylene terephthalate/polylactide (PETG/PLA), glycol‐modified polyethylene terephthalate/polybutylene terephthalate (PETG/PBT)—are used to form an immiscible symmetrical blend (50 wt%/50 wt%). Ultrahigh plastic deformation is achieved by high pressure torsion (HPT). HPT leads to intimate mixing of the chains of the respective polymer pairs. Thermomechanical programming successfully enables a triple shape memory effect with fine shape memory parameters.

Investigation study of methyl violet photodegradation over alginate-carboxymethyl cellulose/titanium(IV) oxide/covalent organic frameworks bio-nanocomposite beads under ultraviolet irradiation

Concerned about water treatment, it is of great importance to present new approaches for improving photocatalytic activity. Since photocatalysis is ubiquitous in almost all chemical manufacturing processes, the development of photocatalytic systems carries significance for our environment. In this regard, three different amounts of covalent organic frameworks decorated with titanium(IV) oxide nanoparticles (TiO2/COF hybrids) in Alginate-Carboxymethyl cellulose (Alg-CMC) blend matrix were prepared under ultrasound irradiation, which Citric acid and Calcium chloride acted as two green cross-linkages. Based on the physio-chemical analyses of these bio-nanocomposite (bio-NC) beads, the Alg-CMC blend polymer appeared to be the best candidate for a disparity of TiO2/COF hybrids. Not only did COF aid to increase the distribution of TiO2 nanoparticles, but it declined the bandgap energies. The resultant Alg-CMC/TiO2/COF (TiO2/COF = 15:6) bio-NC beads demonstrated efficient photodegradation activity towards Methyl violet (MV) under Ultraviolet light. The obtained results of scavenger studies indicated that superoxide radicals and electron agents played a major role in MV degradation. Further investigation confirmed that single oxygen addition and N-de-methylation could be two important pathways for the decomposition of MV by these bio-NC beads.

Tribological Properties of Recycled Polyvinyl Butyral (rPVB) and Glass-Fiber-Reinforced Polyamide Blends in Dry and Microabrasive Contacts

As a contribution of recycling of polymers in the automotive industry, recycled polyvinyl butyral (rPVB) from automotive windshields is being explored as a solid lubricant reinforcement for improving lubricity of engineering polymers. This work aims to evaluate the tribological behavior (coefficient of friction [CoF] and wear resistance) of polyamide 6 (PA6) and glass-fiber-reinforced polyamide 6 (PAGF) blended with rPVB as solid lubricant under two-body and three-body abrasive conditions. The different polymer blends were produced by adding recycled polyvinyl butyral (rPVB) into a matrix of either a commercial polyamide 6 (PA6) or a commercial 30% glass-fiber reinforced polyamide 6 (PAGF). The tribological tests were conducted in an instrumented microabrasion tester for generating wear and measuring the coefficient of friction (CoF) in both dry and microabrasion conditions. In the dry condition, rPVB was effective in reducing the CoF for both PA6 and PAGF. Two-body abrasion was found as the predominant wear pattern in the dry condition. On the other hand, in the microabrasion condition, the additions of rPVB were not totally effective since they produced a wear resistance increase for PAGF but a reduction for PA6, which was ascribed to a notable decrease in toughness for PA6 when adding rPVB. Well-defined plowing traces and several SiC particles embedded in the scars were the predominant patterns in all the materials. In both PA6 and PAGF, CoF increased with the rPVB additions.

Effects of Modified Silicon Carbide on The Physical Properties of Bioplastic Blends

The study’s goal is to improve the physical properties of biodegradable plastics by mixing poly(lactic acid) (PLA), polybutylene succinate (PBS), and silicon carbide (SiC) to make composites that could be used as filaments for 3D printing. Polymer blends and composites were fabricated using an internal mixer. The fraction of SiC was varied from 10 to 40 phr and filled in PLA/PBS blends with a retained ratio of 80/20 wt.%. Then, the mechanical properties, thermal properties, melt flow rate and morphology of PLA/PBS/SiC composites were investigated. Field emission scanning electron microscope images present a uniform dispersion of silane-treated SiC particles throughout the PLA/PBS matrix. The morphology showed better adhesion between PLA/PBS and treated SiC particles. Therefore, this was also the reason for the improvement of Young’s modulus and impact strength when the SiC fraction was increased, which were improved by 33% and 104%, respectively, compared to neat PLA. Furthermore, the melt flow rate increased with an increasing SiC fraction. This might be because adding SiC reduces the viscosity of the composites, which affects the molecular chain movement of the PLA/PBS and the crystallinity of PLA, therefore decreasing the ΔHm of PLA and Xc,PLA. However, Tg and Tm of PLA and PBS remained relatively stable with an increasing fraction of SiC particles.

Influence of ZnMn2O4/CuCo2O4 nano-fillers on the optical and electrical properties PVA/CMC/PEG blended polymers

(1-x)ZnMn2O4/xCuCo2O4 samples were synthesized by the co-precipitation method while polyvinyl alcohol/carboxymethyl cellulose/polyethylene glycol (PVA/CMC/PEG) blended polymer were fabricated by the casting method. Rietveld refinement analysis was used to determine the crystallite size and phase percentages for each composition were determined for all samples. The morphology and structure of PVA/CMC/PEG/(1-x)ZnMn2O4/xCuCo2O4 blends were examined using scanning electron microscopy and x-ray diffraction techniques. The reflectance and transmittance spectra were examined for blended polymers using a diffused reflectance spectrophotometer. Using LCR meter, the prepared blend films' dielectric properties were evaluated. When the blend is loaded with 0.9ZnMn2O4/0.1CuCo2O4, the lowest transmittance values (29–47 %) in the visible region are reached. As the CuCo2O4 doping levels became 10 % in the filler, the smallest direct and indirect energy gap values of 5.4 and (4.47, 1.9, 1.65) eV were attained, respectively. The linear and nonlinear optical parameters affected by the amount of CuCo2O4 in the filler samples. The optical conductivity of the doped blend reached its maximum value at x = 0.15. The CIE chromaticity diagrams revealed that the blends have varying degrees of blue color. The addition of (1-x)ZnMn2O4/xCuCo2O4 fillers improves the energy storage capability of the blends without raising the energy dissipation. The highest value of AC conductivity was achieved with the blend containing 0.9ZnMn2O4/0.1CuCo2O4. Nyquist plot revealed that the ionic conductivity increased as a result of doping. The obtained results suggest that the doped PVA/CMC/PEG/(1-x)ZnMn2O4/xCuCo2O4 blends might be used in a variety of industrial applications, including solar cell technology.

Enabling low molecular weight electrospinning through binary solutions of polymer blends

The formation of nanofibrous membranes via electrospinning is typically restricted to high molecular weight polymers in an appropriate solvent, correlated with the necessary formation of polymer chain entanglements that are needed to achieve successful production of electrospun fibers. The present work extends the electrospinning of low molecular weight polymers by investigating the electrospinning of a binary solution system consisting of two different low molecular weight polymers, using as a model system polycaprolactone (PCL) and gelatin in different ratios. The viscosities of the polymer solutions were characterized as a proxy for polymer chain entanglement and the resulting fibers were morphologically characterized by SEM imaging and further assessed water contact angle and molecular composition to determine the impact and homogeneity of the binary mixtures. We found that unitary solutions of either PCL or gelatin failed to generate proper fibers despite indications of chain entanglement. In contrast, binary solutions of low molecular weight PCL and gelatin generated different fiber quality and size distributions, depending on the ratio used, with direct correlations between fiber properties and the PCL:Gelatin ratio. It was discovered that the ratio of PCL to gelation was most predictive for successful fiber generation, with effective electrospinning occurring only for a define intermediate range of high blend ratios while both low and high blended binary solutions resulted in poor fiber production. Our study confirmed that this behavior was independent from absolute polymer concentration, indicating a unique interaction between these binary species which exists only under specific ratio concentrations and indicates promising new avenues to process low molecular weight polymers solutions.

Amyloid peptide - synthetic polymer blends with enhanced mechanical and biological properties.

Interest in utilizing amyloids to develop biomaterials is increasing due to their potential for biocompatibility, unique assembling morphology, mechanical stability, and biophysical properties. However, challenges include the complexity of peptide chemistry and the practical techniques required for processing amyloids into bulk materials. In this work, two decapeptides with fibrillar and globular morphologies were selected, blended with poly(ethylene oxide), and fabricated into composite mats via electrospinning. Notable enhancements in mechanical properties were observed, attributed to the uniform distribution of the decapeptide assemblies within the PEO matrix. Morphological differences, such as the production of thinner nanofibers, are attributed to the increased conductivity from the zwitterionic nature of the decapeptides. Blend rheology and post-processing analysis revealed how processing might affect the amyloid aggregation and secondary structure of the peptides. Both decapeptides demonstrated good biocompatibility and strong antioxidant activity, indicating their potential for safe and effective use as biomaterials. By evaluating these interdependencies, this research lays the foundation for understanding the structure-property-processing relationships of peptide-polymer blends and highlights the strong potential for developing applications in biotechnology.

Enhancing the Biodegradability, Water Solubility, and Thermal Properties of Polyvinyl Alcohol through Natural Polymer Blending: An Approach toward Sustainable Polymer Applications.

The escalating environmental crisis posed by single-use plastics underscores the urgent need for sustainable alternatives. This study provides an approach to introduce biodegradable polymer blends by blending synthetic polyvinyl alcohol (PVA) with natural polymers-corn starch (CS) and hydroxypropyl methylcellulose (HPMC)-to address this challenge. Through a comprehensive analysis, including of the structure, mechanical strength, water solubility, biodegradability, and thermal properties, we investigated the enhanced performance of PVA-CS and PVA-HPMC blends over conventional polymers. Scanning electron microscopy (SEM) findings of pure PVA and its blends were studied, and we found a complete homogeneity between the PVA and both types of natural polymers in the case of a high concentration of PVA, whereas at lower concentration of PVA, some granules of CS and HMPC appear in the SEM. Blending corn starch (CS) with PVA significantly boosts its biodegradability in soil environments, since adding starch of 50 w/w duplicates the rate of PVA biodegradation. Incorporating hydroxypropyl methylcellulose (HPMC) with PVA not only improves water solubility but also enhances biodegradation rates, as the addition of HPMC increases the biodegradation of pure PVA from 10 to 100% and raises the water solubility from 80 to 100%, highlighting the significant acceleration of the biodegradation process and water solubility caused by HPMC addition, making these blends suitable for a wide range of applications, from packaging and agricultural films to biomedical engineering. The thermal properties of pure PVA and its blends with natural were studied using diffraction scanning calorimetry (DSC). It is found that the glass transition temperature (Tg) increases after adding natural polymers to PVA, referring to an improvement in the molecular weight and intermolecular interactions between blend molecules. Moreover, the amorphous structure of natural polymers makes the melting temperature ™ lessen after adding natural polymer, so the blends require lower temperature to remelt and be recycled again. For the mechanical properties, both types of natural polymer decrease the tensile strength and elongation at break, which overall weakens the mechanical properties of PVA. Our findings offer a promising pathway for the development of environmentally friendly polymers that do not compromise on performance, marking a significant step forward in polymer science's contribution to sustainability. This work presents detailed experimental and theoretical insights into novel polymerization methods and the utilization of biological strategies for advanced material design.

Effect of polypyrrole incorporation amounts on the optical and electrical properties of PVA/CMC blended polymer for optoelectronic applications

In the present work, hybrid flexible blended polymers of polypyrrole (PPy)/polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC); PVA/CMC/x wt % PPy; were constructed as promising blended materials to be used in various optoelectronics applications. X-ray diffraction and scanning electron microscopy techniques were used to investigate the structure and the surface morphology of polymer nanocomposites. The doped blends have better absorption of the three types of ultraviolet (UVA, UVB, and UVC), as well as the visible spectrum. The transmittance values in the visible range dropped from 90 % to 63 % as the PPy concentration reached 0.5 wt%. At x = 0.5, the minimum direct and indirect optical band gap energy values of (4.82, 4.39, 4.23) eV and (3.76, 3.84, 3.62, 2.93) eV, respectively, were obtained. The incorporation of PPy into the PVA/CMC blend led to a regular rise in the refractive index value within the visible range. The blend doped with 0.5 wt % PPy exhibited the highest optical dielectric constant values within the visible range. The enhancement/reduction in the fluorescence intensity depended on the excitation wavelength and the amount of PPy doping in the blended polymers. The effect of voltage, temperature and the amount of PPy doping on the current behavior of the resulting electric current in all blends was explored. The ohmic and nonohmic natures and the charge transport mechanisms of different blends were determined.

The effect of rotationality on nonlinear shear flow of polymer melts and solutions

By considering the rotationality of shear flow, we distinguish between tube segments created by reptation before the inception of shear flow and those created during flow. Tube segments created before inception of shear flow experience both stretch and orientation, while tube segments created after inception of flow are not stretched, but are only aligned in the flow direction. Based on this idea, the Rotation Zero Stretch (RZS) model allows for a quantitative description of the start-up of shear flow and stress relaxation after step-shear strain experiments, in agreement with data of polystyrene long/short blends and corresponding polystyrene 3-arm star polymers investigated by Liu et al. (Polymer 2023, 281:126125), as well as the shear viscosity data of poly(propylene carbonate) melts reported by Yang et al. (Nihon Reoroji Gakkaishi 2022, 50:127–135). In the limit of steady-state shear flow, the RZS model converges to the Doi-Edwards IA model, which quantitatively describes the steady-state shear viscosity of linear polymer melts and long/short blends. The assumption of “non-stretching” of tube segments created during rotational flow is therefore in agreement with the available experimental evidence. Three-arm star polymers behave in a similar way as corresponding blends of long and short polymers confirming the solution effect of the short arm in asymmetric stars. The analysis of step-shear strain experiments reveals that stress relaxation is at first dominated by stretch relaxation, followed at times larger than the Rouse stretch relaxation time by relaxation of orientation as described by the damping function of the Doi-Edwards IA model. The RZS model does not require any nonlinear-viscoelastic parameter, but relies solely on the linear-viscoelastic relaxation modulus and the Rouse stretch relaxation time.Graphical

High-Biocontent Polymer Blends and Their Wood Plastic Composites: Blending, Compatibilization, and Their Recyclability

High-Biocontent Polymer Blends and Their Wood Plastic Composites: Blending, Compatibilization, and Their Recyclability

Impact of pH and ZnO NPs on the fabricated PVA-PVP/ZnO nanofibers: Morphology, absorption behavior, anticancer, and antibacterial activity

In this study, a cost-effective hydrothermal method was successfully used to synthesize ZnO NPs at different pH levels (8, 10, and 12). Nanofibers were produced from polymeric blends PVA-PVP and PVA-PVP/ZnO nanocomposite precursor through electrospinning. XRD analysis revealed the hexagonal wurtzite structure of the synthesized ZnO NPs, with the dominant crystal plane (101). The impact of pH variation was evident in the increased intensity values of the peaks corresponding to (100), (002), and (101) planes as pH levels rose. The average crystallite size decreased from 31.4 to 27.0 nm using Scherrer's calculation, while the microstrain increased from 11.2 to 12.4 ×10−4 as the pH increased from 8 to 12. As wellas the average particle size of the ZnO NPs decreased from 75.05 to 51.35 nm with increasing pH levels, as depicted in FESEM images. The PVA-PVP/ZnO electrospun nanofibers exhibited smooth surfaces and uniform structures, with average diameters of 80.14, 93.33, and 124.13 nm for pH 8, 10, and 12, respectively. The calculation of the optical energy gap using the ASF approach closely matched Tauc's model, ranging from 3.57 to 3.20 eV. Evaluation of the anticancer activity of the nanofibers against MCF-7 cells showed an increase in cytotoxicity from 18 to 64 % with varying concentrations of ZnO NPs ranging from 6.25 to 100 μg/ml. The highest inhibitory effect (about 16 mm) was observed at pH 12 against gram-positive (Staphylococcus aureus).

Biodegradable Biconstituent Melt-Blown Nonwovens for Air Filtration: Fabrication and Characterization

Melt-blown polypropylene (PP) is extensively used in air filtration due to its low cost, low weight, and easy processing, but there are increasing environmental concerns due to its non-degradability. On the other side biodegradable polymers such as polylactic acid (PLA) present insufficient strength and limited toughness. Polymer blending is a well-known approach to reach optimum properties from at least two polymers. This study aims to produce biodegradable PP-PLA-based filter materials that possess enhanced elasticity and superior filtration performance. The addition of PLA raises the average fiber diameter (AFD), causing the PP-PLA filters to have AFD ranging from 0.73 to 0.91 μm. However, the incorporation of zinc stearate (ZnSt) decreased the melt viscosity, resulting in thinner fiber formations with AFD ranging from 0.6 to 0.75 μm for PP-PLA-ZnSt. The efficiency of the corona-charged optimized sample (double-layer 75PP-25PLA-ZnSt) showed 97.42% particle capture efficiency and filtration performance of 0.12 mmH2O−1. Despite the presence of hydrophobic surfaces in all filter materials, the addition of ZnSt further improves the resistance to surface wettability. 75PP-25PLA-ZnSt filter material exhibits high stretchability, with a maximum tensile strength of 380 ± 70 kPa. The proposed tricomponent (PP-PLA-ZnSt) approach would be used to reduce the environmental impact of non-degrading polymers.Graphical abstract

An experimental investigation of process parameters on material removal and surface roughness improvement in abrasive flow machining

There is a huge demand for mechanical components with long life cycles and superior surface finishes as a result of the Industrial Revolution. Several methods for nano-finishing complex structures, including abrasive flow machining (AFM), have been developed in response to the need for superior surface finish. In AFM, abrasion only happens in locations where flow is restricted. This property makes AFM useful in polishing the interior, inaccessible cavities and recesses of the metallic parts using a semi-liquid paste. This paper focuses on investigating the impact of process parameters on material removal, and percentage improvement in surface roughness on cylindrical brass workpieces using Taguchi L9 orthogonal array. The number of cycles, extrusion pressure, and grit size of abrasives have been selected as process parameters. The abrasive medium employed in this investigation is composed of a blend of polymer, hydrocarbon gel, and aluminium oxide abrasive particles with varying grit sizes. The minimum value of roughness after AFM has been achieved 4.25 microns, and the maximum %ΔRa has been achieved 28%. The number of cycles that have the largest percentage contribution to material removal was 83.74%. Whereas, the percentage contributions of the abrasive particle grit size and extrusion pressure are 2.03%, and 14.16%, respectively. N2P2G3 is the optimal level of process parameters used for material removal. Similarly, the number of cycles has the largest percentage contribution of 83.48% in surface roughness. Whereas extrusion pressure and grit size contribute 7.38%, and 8.88% in surface roughness. The optimal level of process parameters that have been attained in the case of surface roughness is N3P2G3.

Effect of calcium bromide hydrate on the structural and optical properties of polyethylene glycol/niobium pentoxide polymer layers

The blend polymer layers of polyethylene glycol with various Nb2O5 and CaBr2⋅xH2O concentrations were synthesized using the solution-dropping process. X-ray diffraction spectra revealed polyethylene glycol peaks, which could be attributed to the polymers' inherent semi-crystalline phase. The Raman spectra revealed stretching Nb–O bonds and confirmed the Nb2O5 phase. The stretching modes of the CH, CH2, and CH3 groups are presented for polyethylene glycol. Adding more CaBr2⋅xH2O (0–3 wt%) increases the transmittance values to about 0.64 %, 1.18 %, 2.79 %, and 6.29 %. At the same time, the band gap values of the polymer layers go down from 3.0 eV to 2.06 eV. The refractive index values increased from 6.16 (0 wt% CaBr2⋅xH2O) to 7.46 (3 wt% CaBr2⋅xH2O). The low Urbach energy of 837.26 meV for the 2 g polyethylene glycol/4 wt% Nb2O5/1 wt% CaBr2⋅xH2O sample confirms the appropriate concentration of less disorder in the polymer layer.

Innovative enhancements in polymer nanocomposites: Integrating ZnO nanorods into Hydroxypropyl methylcellulose/Polyvinyl pyrrolidone blend for advanced energy storage devices

Polymer nanocomposites are promising for various industrial and scientific applications due to their flexibility, diverse functionalities, and unique properties. In this study, zinc oxide nanorods (ZnO NRs) were incorporated into a blend of polymers (Hydroxypropyl methylcellulose - HPMC and Polyvinyl pyrrolidone - PVP) using a solution-casting technique, with concentrations varying from 2 % to 8 % by weight. Transmission electron microscopy (TEM) revealed that the ZnO NRs had an average diameter of 140 nm and a length of 3.22 μm. X-ray diffraction (XRD) analysis showed reduced crystallinity in the samples as the ZnO NR content increased. Fourier-transform infrared spectroscopy (FTIR) indicated changes in vibrational peaks due to interactions between functional groups in the blend and the nanorods. The addition of ZnO NRs significantly influenced the optical bandgap energies and UV/visible light absorption spectra of the samples. The bandgap of the nanocomposites significantly decreased upon ZnO NR incorporation, with direct and indirect bandgaps ranging from 5.19 to 4.70 eV and 4.74–3.66 eV, respectively. Electrical conductivity and dielectric characteristics were assessed across frequencies ranging from 0.1 to 10 MHz, revealing increasing AC conductivity, dielectric permittivity, and dielectric loss with higher ZnO NR content. Notably, at 10 Hz, the electrical conductivity increased from 3.5 × 10⁻12 S/m to 3.62 × 10⁻10 S/m upon loading with ZnO NR. The combination of adjustable optical bandgaps, frequency-dependent AC conductivity, and a wide range of tunable permittivity highlights the potential of these HPMC/PVP-ZnO NR nanocomposites for developing flexible optoelectronic and energy storage devices.

Leveraging Insulator's Tacticity in Semiconducting Polymer Blends.

Blending conjugated polymers with insulating matrices is often utilized for engineering extrinsic properties in organic electronics. Semiconductor/insulator blends are typically processed to form a uniformly distributed network of conductive domains within the insulating matrix, marrying electronic and physical properties from individual components. Understanding of polymer-polymer interactions in such systems is thus crucial for property co-optimization. One of the commonly overlooked parameters is the structural configuration of the insulator on the resulting properties, especially the electronic properties. This study investigated how the tacticity of the matrix polymer, among other relevant parameters in play, impacts solid state crystallization in semiconductor/matrix blends and hence the resulting charge transport properties. We found an intricate dependence of the film morphology, aggregation behavior, electronic charge transport, and mixed ionic-electronic coupling properties on the insulator's tacticity. Our experimentally iterative approach shows that for a given application, when selecting semiconductor/insulator combinations, the tacticity of the matrix can be leveraged to optimize performance and vary solid-state structure.

Thermal, Morphological, Mechanical, and Biodegradation Properties of Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)/High-Density Polyethylene Blends.

Polymer blends of poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) (PLLA-PEG-PLLA) and high-density polyethylene (HDPE) with different blend ratios were prepared by a melt blending method. The thermal, morphological, mechanical, opacity, and biodegradation properties of the PLLA-PEG-PLLA/HDPE blends were investigated and compared to the PLLA/HDPE blends. The blending of HDPE improved the crystallization ability and thermal stability of the PLLA-PEG-PLLA; however, these properties were not improved for the PLLA. The morphology of the blended films showed that the PLLA-PEG-PLLA/HDPE blends had smaller dispersed phases compared to the PLLA/HDPE blends. The PLLA-PEG-PLLA/HDPE blends exhibited higher flexibility, lower opacity, and faster biodegradation and bioerosion in soil than the PLLA/HDPE blends. Therefore, these PLLA-PEG-PLLA/HDPE blends have a good potential for use as flexible and partially biodegradable materials.

Empowering PLA Bioplastics: Elevating applications horizon through groundbreaking Eco-Innovative Fibrillation, chain Extension, and crosslinking techniques

This comprehensive study introduces pioneering techniques in the toughening of polylactic acid (PLA) by incorporating thermoplastic polyurethane (TPU) nanofibrils, leveraging two distinct crosslinking methods to significantly enhance the material’s mechanical performance. Method 1 employs a silane/moisture crosslinking process, whereas Method 2 utilizes a tailored diisocyanate crosslinking approach, offering a more environmentally sustainable alternative. Molecular structural analysis was performed extensively by using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), rheological assessments, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Method 2 not only preserves TPU nanofibrils but also elevates the mechanical properties of PLA-TPU composites beyond the capabilities of Method 1. Notably, by leveraging the simultaneous crosslinking of TPU and chain extension of PLA with the tailored diisocyanate approach, we enhance PLA’s mechanical properties and energy absorption capabilities. These advancements are achieved without a high rubber content, which typically compromises strength/stiffness, thermomechanical stability, crystallization, and transparency of PLA. The resulting composites prepared via Method 2 display remarkable increases in tensile toughness, ranging from 30-60 MPa, and impact strength, achieving a span of 60–140 J/m. This is primarily due to the occurrence of a brittle-to-ductile transition (BDT) at only 3 wt% nanofibril TPU content while maintaining a high PLA modulus of 3 GPa. This critical balance between chain-extending and crosslinking reactions ensures the maintenance of PLA’s inherent strength/stiffness, crystallization, and optical clarity. The research presented here marks a significant shift in the development of tougher, more thermally stable, transparent, and sustainable polymer blends and composites. Method 2, with its tailored fiber size reduction (90–280 nm), and environmental consciousness, broadens the horizon of PLA’s applications.

Preparation and characterization of conjugated PVA/PANi blend films doped with functionalized graphene for thermoelectric applications

Flexible nanocomposite thick films consisting of PVA0.7PANi0.3 polymer blend doped with different concentrations of nanoplatelets functionalized Graphene (NPFGx) (where x = 0, 5, 10, 15, 20, and 25 wt.%) were fabricated using the solution cast technique. Scanning electron microscopy (SEM), X-ray diffractometer (XRD), energy dispersive spectroscopy analysis (EDX), and Fourier-transform infrared spectra (FT-IR) were used to study the structure of the samples. The results showed that the ordered structure, its orientation, the PANis' well dispersion, and the electrostatic forces play a significant role in enhancing the interfaces between the polymer blend and the NPFG. Thermogravimetric analyses (TGA) and Thermoelectrical analyses (TE) showed that the PVA-PANi conducts a promised conjugated blend for thermoelectric applications. The introduction of the NPFG contents into the blend increased the TE measurements as the DC electrical conductivity ≈ 0.0114 (S cm−1), power factor ≈ 3.93 × 10–3 (W m−1 K−2), and Z.T. ≈ 8.4 × 10–7, for the 25 wt.% NPFG nanocomposite film. The effect of the polymers’ phonon contribution in the thermal conductivity controlling and enhancing the thermal stability of the prepared nanocomposite films.