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Search Results (445)

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Keywords = homopolymers

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19 pages, 2232 KiB  
Article
Impact of Co-Substrates on the Production of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Burkholderia thailandensis E264
by Jonathan Uriel Hernández-Alonso, María Alejandra Pichardo-Sánchez, Sergio Huerta-Ochoa, Angélica Román-Guerrero, Oliverio Rodríguez-Fernández, Humberto Vázquez-Torres, Roberto Olayo-González, Roberto Olayo-Valles, Luis Víctor Rodríguez-Durán and Lilia Arely Prado-Barragán
Materials 2025, 18(15), 3577; https://doi.org/10.3390/ma18153577 - 30 Jul 2025
Viewed by 174
Abstract
The synthesis of bioplastics from renewable resources is essential for green living. PHBV (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)) is a biodegradable and biocompatible material ideal for various industrial applications. The impact of levulinic (LA), valeric acids (VA), and sodium propionate (SPr) as co-substrates in biomass and the [...] Read more.
The synthesis of bioplastics from renewable resources is essential for green living. PHBV (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)) is a biodegradable and biocompatible material ideal for various industrial applications. The impact of levulinic (LA), valeric acids (VA), and sodium propionate (SPr) as co-substrates in biomass and the synthesis of 3-hydroxy valerate (3HV) and co-polymerization of PHBV by Burkholderia thailandensis E264 (BtE264) was assessed. Thermogravimetric, XRD, NMR, and mechanical characterization were performed on the homopolymer (PHB) and co-polymer (PHBV), and compared to the PHBV-STD. BtE264 produced the co-polymer PHBV when adding any of the three co-substrates. LA showed a higher positive effect on microbial growth (8.4 g∙L−1) and PHBV production (3.91 g∙L−1), representing 78 and 22 mol % of 3HB and 3HV, respectively. The PHBV obtained with LA had a melting temperature (Tm) lower than the PHB homopolymer and presented lower values for melting enthalpies (ΔHf); the degree of crystallization and TGA values indicated that PHBV had better thermal stability. Additionally, FTIR and NMR revealed that BtE264 synthesizes PHBV with an organization in monomeric units (3HB-3HV), suggesting differentiated incorporation of the monomers, improving 3.4 times the break elongation the co-polymer’s tensile properties. This study highlights the co-substrates’ relevance in PHBV synthesis using BtE264 for the first time. Full article
(This article belongs to the Section Biomaterials)
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18 pages, 2337 KiB  
Article
Thermoplastic and Biocompatible Materials Based on Block Copolymers of Chitosan and Poly(ε-caprolactone)
by Ivan Lednev, Sergey Zaitsev, Ekaterina Maltseva, Roman Kovylin and Larisa Smirnova
Polysaccharides 2025, 6(3), 63; https://doi.org/10.3390/polysaccharides6030063 - 16 Jul 2025
Viewed by 444
Abstract
The development of materials based on chitosan and polyesters that possess thermoplastic, biocompatible, and biodegradable properties is a perspective for additive technologies in biomedicine. Research on obtaining such compositions is constrained because the polysaccharide content does not exceed 5 wt.%, which cannot ensure [...] Read more.
The development of materials based on chitosan and polyesters that possess thermoplastic, biocompatible, and biodegradable properties is a perspective for additive technologies in biomedicine. Research on obtaining such compositions is constrained because the polysaccharide content does not exceed 5 wt.%, which cannot ensure effective tissue regeneration. Herein, we propose a method for obtaining thermoplastic block copolymers based on chitosan and poly(ε-caprolactone) by ultrasonic irradiation of a homogeneous solution of a homopolymer mixture in dimethyl sulfoxide as a common solvent, achieving a yield of 99%. The distinctive feature of the method is the interaction between the components at the molecular level and provides obtaining copolymers at any component ratio. SEM images revealed a homogeneous structure without structural defects in both solvent-cast films and extruded filaments. The block copolymers were characterized by high mechanical property tensile strength of up to 60–70 MPa and elasticity of up to 35% for films and 25–40 MPa and elasticity of up to 50% for filaments. Cell adhesion of composition investigated on fibroblast cells (hTERT BJ-5TA) is at the level of chitosan and demonstrated the absence of cytotoxicity. Full article
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20 pages, 2317 KiB  
Article
Multifunctional Amphiphilic Biocidal Copolymers Based on N-(3-(Dimethylamino)propyl)methacrylamide Exhibiting pH-, Thermo-, and CO2-Sensitivity
by Maria Filomeni Koutsougera, Spyridoula Adamopoulou, Denisa Druvari, Alexios Vlamis-Gardikas, Zacharoula Iatridi and Georgios Bokias
Polymers 2025, 17(14), 1896; https://doi.org/10.3390/polym17141896 - 9 Jul 2025
Viewed by 450
Abstract
Because of their potential “smart” applications, multifunctional stimuli-responsive polymers are gaining increasing scientific interest. The present work explores the possibility of developing such materials based on the hydrolytically stable N-3-dimethylamino propyl methacrylamide), DMAPMA. To this end, the properties in aqueous solution of the [...] Read more.
Because of their potential “smart” applications, multifunctional stimuli-responsive polymers are gaining increasing scientific interest. The present work explores the possibility of developing such materials based on the hydrolytically stable N-3-dimethylamino propyl methacrylamide), DMAPMA. To this end, the properties in aqueous solution of the homopolymer PDMAPMA and copolymers P(DMAPMA-co-MMAx) of DMAPMA with the hydrophobic monomer methyl methacrylate, MMA, were explored. Two copolymers were prepared with a molar content x = 20% and 35%, as determined by Proton Nuclear Magnetic Resonance (1H NMR). Turbidimetry studies revealed that, in contrast to the homopolymer exhibiting a lower critical solution temperature (LCST) behavior only at pH 14 in the absence of salt, the LCST of the copolymers covers a wider pH range (pH > 8.5) and can be tuned within the whole temperature range studied (from room temperature up to ~70 °C) through the use of salt. The copolymers self-assemble in water above a critical aggregation Concentration (CAC), as determined by Nile Red probing, and form nanostructures with a size of ~15 nm (for P(DMAPMA-co-MMA35)), as revealed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The combination of turbidimetry with 1H NMR and automatic total organic carbon/total nitrogen (TOC/TN) results revealed the potential of the copolymers as visual CO2 sensors. Finally, the alkylation of the copolymers with dodecyl groups lead to cationic amphiphilic materials with an order of magnitude lower CAC (as compared to the unmodified precursor), effectively stabilized in water as larger aggregates (~200 nm) over a wide temperature range, due to their increased ζ potential (+15 mV). Such alkylated products show promising biocidal properties against microorganisms such as Escherichia coli and Staphylococcus aureus. Full article
(This article belongs to the Special Issue Development and Innovation of Stimuli-Responsive Polymers)
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14 pages, 1220 KiB  
Article
Viscoelastic Response of Double Hydrophilic Block Copolymers for Drug Delivery Applications
by Achilleas Pipertzis, Angeliki Chroni, Stergios Pispas and Jan Swenson
Polymers 2025, 17(13), 1857; https://doi.org/10.3390/polym17131857 - 2 Jul 2025
Viewed by 350
Abstract
This study investigates the mechanical properties of double hydrophilic block copolymers (DHBCs) based on poly[oligo(ethylene glycol) methacrylate] (POEGMA) and poly(vinyl benzyl trimethylammonium chloride) (PVBTMAC) blocks by employing small amplitude oscillatory shear (SAOS) rheological measurements. We report that the mechanical properties of DHBCs are [...] Read more.
This study investigates the mechanical properties of double hydrophilic block copolymers (DHBCs) based on poly[oligo(ethylene glycol) methacrylate] (POEGMA) and poly(vinyl benzyl trimethylammonium chloride) (PVBTMAC) blocks by employing small amplitude oscillatory shear (SAOS) rheological measurements. We report that the mechanical properties of DHBCs are governed by the interfacial glass transition temperature (Tginter), verifying the disordered state of these copolymers. An increase in zero shear viscosity can be observed by increasing the VBTMAC content, yielding a transition from liquid-like to gel-like and finally to an elastic-like response for the PVBTMAC homopolymer. By changing the block arrangement along the backbone from statistical to sequential, a distinct change in the viscoelastic response is obvious, indicating the presence/absence of bulk-like regions. The tunable viscosity values and shear-thinning behavior achieved through alteration of the copolymer composition and block arrangement along the backbone render the studied DHBCs promising candidates for drug delivery applications. In the second part, the rheological data are analyzed within the framework of the classical free volume theories of glass formation. Specifically, the copolymers exhibit reduced fractional free volume and similar fragility values compared to the PVBTMAC homopolymer. On the contrary, the activation energy increases by increasing the VBTMAC content, reflecting the required higher energy for the relaxation of the glassy VBTMAC segments. Overall, this study provides information about the viscoelastic properties of DHBCs with densely grafted macromolecular architecture and shows how the mechanical and dynamical properties can be tailored for different drug delivery applications by simply altering the ratio between the two homopolymers. Full article
(This article belongs to the Special Issue Advances and Applications of Block Copolymers II)
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17 pages, 4850 KiB  
Article
The Scissors Effect of the Macromolecular Crosslinker on the Glass Transition of Polystyrene in Its Conetworks with Poly(dimethylsiloxane)
by Anna Petróczy, István Szanka, Laura Bereczki, Nóra Hegyesi, János Madarász and Béla Iván
Polymers 2025, 17(12), 1656; https://doi.org/10.3390/polym17121656 - 14 Jun 2025
Viewed by 492
Abstract
The glass transition temperature (Tg) is undoubtedly one of the most important characteristics of polymers, and investigating its dependence on their structure and composition is crucial from both fundamental and application points of view. This study deals with the unexpected [...] Read more.
The glass transition temperature (Tg) is undoubtedly one of the most important characteristics of polymers, and investigating its dependence on their structure and composition is crucial from both fundamental and application points of view. This study deals with the unexpected relationship between Tg and the average molecular weight between crosslinking points (Mc) in nanophase-separated polystyrene-l-poly(dimethylsiloxane) (PSt-l-PDMS) and polystyrene-l-poly(dimethylsiloxane)/divinylbenzene (PSt-l-PDMS/DVB) polymer conetworks. In order to reveal the correlation between the Tg and Mc, a library of PSt-l-PDMS and PSt-l-PDMS/DVB conetworks was synthesized, and their compositions and Tgs were determined. Instead of the expected increase of Tg with decreasing Mc, a reverse correlation was found. Namely, the Tg decreases with decreasing Mc in these conetworks. Correlation analyses showed that the Tg linearly depends on 1/Mc, similar to the Fox–Flory relationship for homopolymers with their Mn, that is, Tg = Tg,ꝏK/Mc for the investigated conetworks, independent of the absence or presence of relatively low amounts of DVB as an additional small molecular weight crosslinker. This means that the PDMS macrocrosslinker acts like scissors by interrupting the mobility of the crosslinked PSt chains in the conetworks, and the Tg of the PSt segments will be close to that of PSt homopolymers with the same Mn as Mc, as found by comparison. Consistent with previous findings with other conetworks, the presence of the scissors effect of the macromolecular crosslinker in the PSt-l-PDMS and PSt-l-PDMS/DVB conetworks indicates that the scissors effect is a general phenomenon for polymer conetworks formed by crosslinking with a macromolecular crosslinker. The observed unusual Tg versus Mc relationship in the conetworks can be utilized in designing such novel materials with predetermined Tgs required for targeted applications. Full article
(This article belongs to the Section Polymer Analysis and Characterization)
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26 pages, 11179 KiB  
Article
Surface Morphology and Degradation of Poly[(R)-3-Hydroxybutyrate]-block-Poly(ε-Caprolactone) and Poly[(R)-3-Hydroxybutyrate]-block-Poly(l-Lactide) Biodegradable Diblock Copolymers
by Ayan Bartels-Ellis, Senri Hayashi, Tomohiro Hiraishi, Takeharu Tsuge and Hideki Abe
Polymers 2025, 17(11), 1558; https://doi.org/10.3390/polym17111558 - 3 Jun 2025
Viewed by 581
Abstract
Bacterially produced poly[(R)-3-hydroxybutyrate] (P3HB) was subjected to an alcoholysis reaction to produce low-molecular-weight (Mn ≈ 10,000 g mol−1) hydroxy-terminated P3HB (LMPHB). Using diethyl zinc as a catalyst, LMPHB was reacted with the cyclic monomers ε-caprolactone and l [...] Read more.
Bacterially produced poly[(R)-3-hydroxybutyrate] (P3HB) was subjected to an alcoholysis reaction to produce low-molecular-weight (Mn ≈ 10,000 g mol−1) hydroxy-terminated P3HB (LMPHB). Using diethyl zinc as a catalyst, LMPHB was reacted with the cyclic monomers ε-caprolactone and l-lactide in separate ring-opening polymerization (ROP) reactions to produce PHB-b-PCL (PHBCL) and PHB-b-PLA (PHBLA) AB-type crystalline–crystalline diblock copolymers with varying PCL and PLA block lengths. 1H NMR and GPC were used to confirm the structure of the polymers. DSC was used to measure the thermal properties as well as assessing crystallization. A single-shifting Tg for PHBLA showed the two blocks to be miscible in the melt. The TGA results indicate enhanced thermal stability over the homopolymer P3HB. A study of the crystallization was undertaken by combining WAXD, a second DSC heating regime, and POM. POM showed that the crystallization in PHBCL to be dependent on the crystallization temperature more so than PHBLA, whose composition appeared to be the more definitive factor determining the spherulitic morphology. The results informed the crystallization temperatures used in the production of the melt-crystallized thin films that were imaged using AFM. AFM images showed unique surface morphologies dependent on the diblock copolymer composition, block length, and crystallization temperature. Finally, the enzymatic degradation studies showed these unique surface morphologies to influence how these block copolymers were degraded by enzymes. Full article
(This article belongs to the Section Biobased and Biodegradable Polymers)
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12 pages, 1908 KiB  
Article
The First Example of a Model Amphiphilic Polymer Conetwork Containing a Hydrophobic Oligopeptide: The Case of End-Linked Tetra[Poly(ethylene glycol)-b-oligo(L-alanine)]
by Demetris E. Apostolides, George Michael, Costas S. Patrickios, Takamasa Sakai, Iro Kyroglou, Maria Kasimatis, Hermis Iatrou, Sylvain Prévost and Michael Gradzielski
Gels 2025, 11(5), 331; https://doi.org/10.3390/gels11050331 - 29 Apr 2025
Cited by 1 | Viewed by 535
Abstract
Herein we describe the development of the first model amphiphilic polymer conetwork (APCN) comprising a short hydrophobic hexa(L-alanine) segment being the outer block of an amphiphilic four-armed star block copolymer with inner poly(ethylene glycol) (PEG) blocks bearing benzaldehyde terminal groups and [...] Read more.
Herein we describe the development of the first model amphiphilic polymer conetwork (APCN) comprising a short hydrophobic hexa(L-alanine) segment being the outer block of an amphiphilic four-armed star block copolymer with inner poly(ethylene glycol) (PEG) blocks bearing benzaldehyde terminal groups and end-linked with another four-armed star PEG homopolymer (tetraPEG star) bearing aryl-substituted acylhydrazide terminal groups. The present successful synthesis that yielded the peptide-containing model APCN was preceded by several unsuccessful efforts that followed different synthetic strategies. In addition to the synthetic work, we also present the structural characterization of the peptide-bearing APCN in D2O using small-angle neutron scattering (SANS). Full article
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18 pages, 4872 KiB  
Article
Optimizing the Synthesis of CO2-Responsive Polymers: A Kinetic Model Approach for Scaling Up
by Emil Pashayev and Prokopios Georgopanos
Polymers 2025, 17(8), 1115; https://doi.org/10.3390/polym17081115 - 20 Apr 2025
Viewed by 460
Abstract
The kinetic model is a crucial tool for optimizing polymer synthesis protocols and facilitating the scaled-up production processes of the CO2-responsive polymer poly(N-[3-(dimethylamino)propyl]-acrylamide)-b-poly(methyl methacrylate)(PDMAPAm-b-PMMA), which is supposed to be implemented in direct air capture (DAC) technology. This study presents [...] Read more.
The kinetic model is a crucial tool for optimizing polymer synthesis protocols and facilitating the scaled-up production processes of the CO2-responsive polymer poly(N-[3-(dimethylamino)propyl]-acrylamide)-b-poly(methyl methacrylate)(PDMAPAm-b-PMMA), which is supposed to be implemented in direct air capture (DAC) technology. This study presents a simulation of the kinetic model developed for the Reversible Addition−Fragmentation Chain-Transfer (RAFT) polymerization of N-[3-(dimethylamino)propyl]-acrylamide (DMAPAm), alongside an investigation into the kinetics of this polymerization using the simulation as an analytical tool, as well as the application of the simulation for the upscaling of RAFT polymerization. Ultimately, the kinetic model was validated through two kinetic experiments, confirming its reliability. It was subsequently employed to optimize the synthesis recipe and to predict the properties of PDMAPAm homopolymers, thereby supporting the upscaling of PDMAPAm-b-PMMA diblock copolymer synthesis. In the end, the preliminary results of the CO2-responsiveness of the diblock copolymer were determined with a simple experiment. Full article
(This article belongs to the Special Issue Advances and Applications of Block Copolymers II)
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26 pages, 20430 KiB  
Article
Influence of Partial Disentanglement of Macromolecules on the Rheological, Thermal, and Mechanical Properties of Polypropylene–Polyethylene Blends
by Justyna Krajenta, Magdalena Lipinska and Andrzej Pawlak
Molecules 2025, 30(8), 1786; https://doi.org/10.3390/molecules30081786 - 16 Apr 2025
Viewed by 656
Abstract
The properties of compatibilized blends of polyethylene (PE) and polypropylene (PP), having reduced macromolecular entanglements, were studied. The density of PP macromolecular entanglements was controlled by prior disentangling in solution. The polymer ratio in the blend was 4:1 or 1:4. An ethylene–octene copolymer [...] Read more.
The properties of compatibilized blends of polyethylene (PE) and polypropylene (PP), having reduced macromolecular entanglements, were studied. The density of PP macromolecular entanglements was controlled by prior disentangling in solution. The polymer ratio in the blend was 4:1 or 1:4. An ethylene–octene copolymer was used as a compatibilizer. The melt blending process resulted in good dispersion of the minority component, with slightly larger inclusions when more disentangled PP was used. Rheological studies confirmed the achievement of different entanglement densities of PP macromolecules in the blends. The partial disentanglement did not affect the thermal stability of the blends. During the isothermal crystallization studies, faster growth of PP spherulites was observed in the blend with reduced entanglements, which also influenced the entire crystallization process. The recovery time of equilibrium entanglement was investigated and it turned out to be 45 min if the blend was annealed at 190 °C, which was shorter than in the analogous homopolymer. Studies of tensile properties showed that in blends with a majority share of polyethylene, the elongation at break increased with the disentanglement of the minority component, due to better bonding of the blend components and thus the reduction in microcavitation. Full article
(This article belongs to the Special Issue Macromolecular Chemistry in Europe, 2nd Edition)
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12 pages, 3148 KiB  
Article
Chiral Polymers Based on Vinyl[2.2]paracyclophane and Their Application as CPL Emitters
by Henrik Tappert, Emma V. Puttock, Jhon Sebastian Oviedo Ortiz, Eli Zysman-Colman, Jeanne Crassous and Stefan Bräse
Polymers 2025, 17(8), 1070; https://doi.org/10.3390/polym17081070 - 16 Apr 2025
Viewed by 680
Abstract
Chiral molecules are integral to various biological and artificial systems, influencing processes from chemical production to optical activities. In this study, we explore the potential of chiral vinyl[2.2]paracyclophane (vinyl-PCP) as a monomer for the synthesis of homopolymers and copolymers with styrene. We achieved [...] Read more.
Chiral molecules are integral to various biological and artificial systems, influencing processes from chemical production to optical activities. In this study, we explore the potential of chiral vinyl[2.2]paracyclophane (vinyl-PCP) as a monomer for the synthesis of homopolymers and copolymers with styrene. We achieved polymerization through anionic, cationic, and radical methods. The resulting polymers demonstrated significant chiral properties, even in copolymers with small fractions of the chiral monomer. Further, we developed a polymerizable vinyl emitter from 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9,9-dimethyl-9,10-dihydroacridine (DMAC-TRZ) through a two-step synthesis with an overall yield of 48%. Copolymerization with chiral vinyl-PCP resulted in emissive polymers that demonstrated circularly polarized luminescence (CPL) properties. The inclusion of the chiral PCP monomer, acting both as a host material and the source of chirality for CPL, enhanced the photoluminescence quantum yield (PLQY) to 47.2% in N2 at 5–10% emitter content, compared to 26.8% for the pure emitter polymer. CPL-active polymers show clear mirror-image Cotton effects at 240 nm and 267 nm and dissymmetry factors around +2 × 10−4 and −1 × 10−4. This self-hosting effect of PCP monomers underscores the potential of chiral vinyl-PCP for advanced functional materials in optical communication and bio-responsive imaging. Full article
(This article belongs to the Section Polymer Applications)
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16 pages, 15423 KiB  
Article
Monte Carlo Simulations of Polymer Collapse in an Explicit Solvent of Varying Quality
by Piotr Polanowski and Andrzej Sikorski
Polymers 2025, 17(7), 978; https://doi.org/10.3390/polym17070978 - 3 Apr 2025
Cited by 1 | Viewed by 479
Abstract
The behavior of a single homopolymer chain in an explicit solvent in a wide range of poor and good solvents was investigated. For this purpose, a two-dimensional coarse-grained model based on a triangular lattice was used. Simulations were carried out by the Monte [...] Read more.
The behavior of a single homopolymer chain in an explicit solvent in a wide range of poor and good solvents was investigated. For this purpose, a two-dimensional coarse-grained model based on a triangular lattice was used. Simulations were carried out by the Monte Carlo method using the Cooperative Motion Algorithm to study high-density systems. The scaling relations of the parameters describing the phase transitions of the chain were determined. For systems with polymer–solvent attraction, significant changes in chain size and shape were observed. This was associated with the mechanism of chain penetration by solvents and the formation of structures via a mechanism called ‘Bridging-Induced Attraction’, similar to those discovered for three dimensions. Full article
(This article belongs to the Special Issue Polymer Brushes: Synthesis, Characterization and Applications)
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14 pages, 20648 KiB  
Article
Microcanonical Analysis of Semiflexible Homopolymers with Variable-Width Bending Potential
by Matthew J. Williams and Michael C. Gray
Polymers 2025, 17(7), 906; https://doi.org/10.3390/polym17070906 - 27 Mar 2025
Cited by 1 | Viewed by 440
Abstract
Understanding the structural dynamics of semiflexible polymers in an implicit solvent under varying conditions provides valuable insights into their behavior in diverse environments. In this work, we systematically investigate the effect of the angular width of the bending potential on structural state behavior [...] Read more.
Understanding the structural dynamics of semiflexible polymers in an implicit solvent under varying conditions provides valuable insights into their behavior in diverse environments. In this work, we systematically investigate the effect of the angular width of the bending potential on structural state behavior and conformational variability using microcanonical analysis. A range of angular widths is explored, with the widest value corresponding directly to the classic semiflexible polymer model, which exhibits a diverse set of structural states, including Two-Strand, Three-Strand, Four-Strand, Ring, Random Coil, and Globule configurations. As the angular width narrows, structural variability within states decreases, overlap between structural states is reduced, and conformations become more stable, leading to an expansion of the parameter space dominated by individual structures. By examining microcanonical entropy and its derivatives, we identify transitions analogous to first-, second-, and third-order thermodynamic transitions, providing a deeper understanding of the configurational landscape of semiflexible polymers. Full article
(This article belongs to the Special Issue Modeling of Polymer Composites and Nanocomposites)
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18 pages, 5150 KiB  
Article
Effect of Hard-Segment Structure on the Properties of Polyurethane/Poly(Ethyl Methacrylate) Damping Composites
by Jinbao Ma, Chi Ma, Risheng Long, Yan Jiang, Xingjia Wang, Chang Liu, Fan Li and Lee Tin Sin
Polymers 2025, 17(5), 636; https://doi.org/10.3390/polym17050636 - 27 Feb 2025
Viewed by 1183
Abstract
Damping material performance influences the efficacy of vibration and noise reduction. However, traditional damping materials often have low damping peaks or narrow damping temperature ranges. In this study, a series of polyurethane (PU)/poly(ethylene methacrylate) (PEMA) composites were synthesised, in which the PU hard [...] Read more.
Damping material performance influences the efficacy of vibration and noise reduction. However, traditional damping materials often have low damping peaks or narrow damping temperature ranges. In this study, a series of polyurethane (PU)/poly(ethylene methacrylate) (PEMA) composites were synthesised, in which the PU hard segments were varied using toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate. The soft segments comprised tetrahydrofuran homopolymer glycol. The influence of the hard-segment structure on the properties of the PU/PEMA composites was investigated by infrared spectroscopy, thermogravimetric analysis, dynamic mechanical thermal analysis, and other experimental methods. The performance mechanism was explored from a molecular perspective via integration with molecular dynamics simulations. The PU/PEMA material with IPDI hard segments comprised numerous microphase-separated structures and exhibited greater free volume, fuller molecular-chain movement, and the highest damping performance, with a loss factor of 0.56. The PU/PEMA composites synthesised with TDI and MDI hard segments exhibited better compatibility, with the MDI-PU/PEMA system exhibiting a higher hydrogen-bonding force. This material also exhibited a higher thermal stability, with an initial breakdown temperature of 287.87 °C. This study provides a basis for regulating and optimising the performance of PU-based damping materials. Full article
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25 pages, 9495 KiB  
Article
Natural–Synthetic Hybrid Nanostructures Formed Through the Interaction of Chitosan with Carboxylate-Ended PNIPAM: Structure and Curcumin Encapsulation
by Elena-Daniela Lotos, Maria Karayianni, Ana-Lavinia Vasiliu, Marcela Mihai and Stergios Pispas
Nanomaterials 2025, 15(5), 350; https://doi.org/10.3390/nano15050350 - 24 Feb 2025
Cited by 1 | Viewed by 769
Abstract
Chitosan is widely used in drug delivery applications, due to its biocompatibility, bio-degradability, and low toxicity. Nevertheless, its properties can be enhanced through the physical or chemical modification of its amino and hydroxyl groups. This work explores the electrostatic complexation of two chitosan [...] Read more.
Chitosan is widely used in drug delivery applications, due to its biocompatibility, bio-degradability, and low toxicity. Nevertheless, its properties can be enhanced through the physical or chemical modification of its amino and hydroxyl groups. This work explores the electrostatic complexation of two chitosan samples of differing lengths with two poly(N-isopropylacrylamide) (PNIPAM) homopolymers of different molecular weight carrying a chargeable carboxyl end group. This interaction enables the electrostatic binding of PNIPAM side chains onto the chitosan backbone through the amino groups, and could be considered as an alternative grafting method. Dynamic and electrophoretic light scattering techniques were employed in order to study the solution/dispersion properties of the formed complexes as a function of the PNIPAM concentration, or, equivalently, the molar/charge ratio of the two components. The obtained results revealed that their mass, size, and charge mostly depend on the length of the two individual constituents, as well as their mixing ratio. Furthermore, their response to changes in their environment, namely temperature and ionic strength, was also examined, demonstrating the effect of either the thermoresponsiveness of PNIPAM or the electrostatic charge screening, respectively. Fluorescence spectroscopy, utilizing pyrene as a probe, provided information regarding the hydrophobicity of the formed complexes, while images from scanning transmission electron and atomic force microscopies further elucidated their morphology, which was found to be closely related to that of the corresponding chitosan molecule. Finally, their potential as drug delivery vehicles was also investigated, utilizing curcumin as a model drug at various loading concentrations. Full article
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25 pages, 3116 KiB  
Article
Physicochemical and Sensory Evaluation of Sustainable Plant-Based Homopolymers as an Alternative to Traditional Emollients in Topical Emulsions
by Talita Ganem Meneguello, Nathalia Kopke Palma, Yasmin Rosa Santos, Ariel Figueira Carvalho, Ariane Dalan da Silva Ladeira, Fabiana Perrechil Bonsanto, Newton Andreo-Filho, Patricia Santos Lopes, Heather Ann Elizabeth Benson and Vania Rodrigues Leite-Silva
Pharmaceutics 2025, 17(2), 265; https://doi.org/10.3390/pharmaceutics17020265 - 17 Feb 2025
Cited by 2 | Viewed by 766
Abstract
Objectives: This study evaluated the potential of sustainably sourced, plant-based homopolymers derived from citronellol as an alternative to the traditional emollients used in pharmaceutical, cosmetic, and personal care products. With increasing emphasis on environmentally friendly ingredients and manufacturing processes, this study assessed [...] Read more.
Objectives: This study evaluated the potential of sustainably sourced, plant-based homopolymers derived from citronellol as an alternative to the traditional emollients used in pharmaceutical, cosmetic, and personal care products. With increasing emphasis on environmentally friendly ingredients and manufacturing processes, this study assessed the efficacy of these homopolymers in semi-solid and emulsion-based formulations. Methods: The analyses focused on physicochemical, sensory, biophysical, and neurosensory characteristics. Results: The results demonstrated that emulsions containing sustainable homopolymers maintained viscoelastic stability, preserving rheological properties over time under varying conditions. These formulations showed comparable structural and functional stability to those with traditional emollients while offering skin hydration, moisture retention, and elasticity, with reduced transepidermal water loss. Sensory evaluations highlighted positive user acceptance, with participants favoring the skin feel and in-use qualities of these emulsions over synthetic alternatives. Neurosensory analyses confirmed the strong visual appeal of the product packaging, capturing user attention effectively. Conclusions: These findings underline the capability of plant-based homopolymers to replace traditional emollients while providing significant consumer appeal and sustainability benefits. This study establishes their potential as viable components in the development of more eco-friendly topical formulations for the pharmaceutical, cosmetic, and personal care industries. Full article
(This article belongs to the Section Physical Pharmacy and Formulation)
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