Polymer International最新文献

The limited heat resistance and high brittleness of polylactic acid (PLA) materials pose significant challenges to enabling their broad application. Compared to traditional PLA, stereocomplex polylactide (sc-PLA) offers superior thermal stability and a higher melting point, attributed to the dense packing and strong physical interactions between polymer chains. Specifically, while PLA has a melting temperature of approximately 160–180 °C, sc-PLA can reach a melting temperature of 230 °C. The enhanced thermal stability and improved mechanical properties make sc-PLA a valuable alternative for applications requiring durability. Here, we report a method to enhance the crystallinity and toughness of sc-PLA by mixing poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) in addition to using a nucleating agent and toughening agent. Specifically, a PLA and polyethylene glycol block copolymer and PLA microspheres are prepared, with ethylene-methyl acrylate-glycidyl methacrylate used as a toughener. The optimal composition is found to be PLLA/PDLA blends with a 70/30 mass ratio, 1% microsphere nucleating agent and 10% toughener addition. The Vicat softening temperature of this blend is 72.2 °C, approximately 10% higher than the control sample, with toughness increased by about 2.3 times. This blend also presents an enhanced processability by the combined effect of additives. This work provides a promising strategy for producing sc-PLA with enhanced heat resistance and processability, improving the performance for various applications. © 2025 Society of Chemical Industry.

The degradation of polymer-based materials is crucial for their end-of-life management, particularly in biomedical applications where controlled degradation rates are essential. Addressing this need, this study explores the incorporation of newly designed polyanhydrides (PAs) into multicomponent blends to enhance hydrolytic biodegradation. Two distinct PAs – poly[(propionic anhydride)-co-(succinic anhydride)] (PASA) and poly[(propionic anhydride)-co-(sebacic anhydride)] (PASEA) – were synthesized through melt-condensation polymerization. These PAs were then incorporated into solution blend films composed of poly(l-lactide) (PLLA), poly(ε-caprolactone) (PCL) and cellulose acetate butyrate (CAB), aiming to serve as an accelerator for the hydrolytic degradation of films. The incorporation of PASA and PASEA into the PLLA/PCL/CAB blend films resulted in the formation of phase-separated domains and a notable shift of the carbonyl frequency band in the Fourier transform infrared spectra, indicating phase separation and intermolecular packing between homopolymers in the blend system. Significant changes in the molecular weight and surface morphology of the blend films with PAs were observed after 0, 3 and 6 months of storage. These observations confirmed the role of PASA and PASEA in accelerating through surface erosion, as evidenced by the presence of craze lines at both macrophase- and microphase-separated domains. This study highlights the potential of newly designed PA additives to enhance the degradation and stability of PLLA/PCL/CAB polymer-based film. Such enhancements are valuable for designing materials with controlled degradation rates, which is particularly important in biomedical applications where precise timing of degradation within the body is essential. © 2025 Society of Chemical Industry.

Polyhydroxyalkanoates (PHAs) are biodegradable thermoplastics synthesized from renewable biomass resources by various microbes. They have garnered significant attention owing to their superior biodegradability in natural environments compared to other biodegradable plastics. However, preserving their properties while preventing biodegradation during use as plastic material is crucial. In this study, polyethylene glycol (PEG)-grafted PHAs were investigated for the development of biodegradable materials with controlled surface properties. To this end, PHA copolymers containing 6–19 mol% of 3-hydroxy-4-pentenoate (3H4PE), which features an unsaturated side chain as a site for chemical modification, were synthesized using recombinant Escherichia coli and 4-pentenoic acid as 3H4PE precursors. Thiol-PEG (MW 2000) was then grafted onto the PHA at the unsaturated side chain via thiol-ene ‘click’ chemistry reactions. Although the thermal properties of the PEG-grafted PHA showed minimal changes compared with those of the unmodified PHA copolymers, the PEG-grafted PHA films exhibited increased wettability and excellent protein-repellent properties. Furthermore, when biodegradability was tested on an agar plate containing PEG-grafted PHA, the PHA-degrading bacteria did not form clear zones around their colonies when the PEG content was 12 wt%. These results suggest that PEG grafting effectively alters the properties of PHA, offering a promising strategy for controlling its biodegradability and its thermal and antifouling properties. © 2025 Society of Chemical Industry.

When contemplating the manufacturing of subsequent iterations of polymer composites, companies may choose to maximize the exploitation of naturally existing resources for synthesis. The rationale for this decision becomes apparent when considering both environmental and economic factors. Inside the cashew nutshell's honeycomb structure is a viscous, dark-brown liquid called cashew nutshell oil (CNSL). This CNSL is among the few economically viable sources of naturally occurring phenols. Considering that CNSL is easily obtainable, cost-efficient and derived from agricultural waste, this contribution showcases its financially and environmentally viable characteristics. This study made a natural oil-blended epoxy resin using CNSL at 15, 20, 25 and 30 vol.% in synthetic epoxy. Thermal and mechanical properties, morphology analysis, water absorption, flammability and limiting oxygen index (LOI) were used for characterization. In addition, the examination of the link between the structure and properties was conducted using X-ray diffraction analysis. With 20 vol.% CNSL, the epoxy had 12.66%, 18.34%, 10.18%, 13.72% and 3.78% higher flexural strength, compression strength, tensile strength, impact energy and Shore-D hardness, respectively. The water absorption test indicated a mass decrease similar to that of pure epoxy. With 24.71% residual mass at 550 °C compared to 2.66% for pure epoxy, the bio-blended epoxy showed thermal stability. The cured bio-blended epoxy lowered the combustion rate by 9.62% compared to the cured epoxy resin, while no UL94 rating was detected. The LOI range indicates that the cured bio-blended epoxy belongs to the category of materials that burn slowly. © 2025 Society of Chemical Industry.

Silver-containing composites formed by sputtering deposition on the surface of polylactide (PLA) films have been developed; they contain a layer of silver nanoparticles of different thicknesses depending on the deposition time, namely 1, 3 and 5 min. It was found that with a deposition time of 5 min a layer with a thickness of ca 100 nm is formed. The average size of the Ag nanoparticles is 5.9 nm, and the average specific surface area S_sp is 97 m² g⁻¹. The samples obtained were characterized by wide-angle X-ray scattering, TEM, TGA and DSC and their antimicrobial, antiviral and cytotoxic properties were studied as well. It was found that the thinnest layer of silver (deposited for 1 min) has the greatest effect on the PLA's heat resistance and glass transition temperature. PLA-Ag composites formed by silver sputtering deposition show antimicrobial activity against the studied test cultures of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and the activity of the samples increases with increasing duration of silver deposition. PLA-Ag composites formed by silver deposition for 5 min had a weak virucidal effect against herpes simplex virus type 1 and influenza virus type A. Irrespective of the sputtering time of silver the composites obtained were not cytotoxic; at a dilution of 1:10 and more they did not significantly inhibit the viability of MDCK, BHK and Hep-2 cells. © 2025 Society of Chemical Industry.

This study focuses on the synthesis of fluorohydroxyapatite (FHA), and the realization of scaffolds by 3D printing using polylactic acid (PLA) as polymer and graphene oxide (GO). The synthesis of FHA was carried out by the usual sol–gel method. The realization of the 3D scaffold was achieved with the 3D printing method. Four scaffolds were printed with PLA: the first was made with FHA and PLA (FHA/PLA), the second was made with GO in addition to FHA and PLA (FHA/PLA/GO), and the third and fourth ones were the FHA/PLA and FHA/PLA/GO scaffolds coated with electrosprayed hydrogel solution of doxorubicin (DOX) and polyvinyl alcohol (PVA): FHA/PLA/DOX/PVA and FHA/PLA/GO/DOX/PVA. The FHA and GO powders were characterized using Fourier transform infrared analysis and X-ray diffraction analysis. A dissolution study was carried out with different contents of PVA (2.5%, 3% and 4%) to identify the scaffold with the best drug release profile. The 3% w/w PVA hydrogel solution was the best, so the drug release kinetics and drug release mechanism were studied using the most famous mathematical models: zero-order model, Higuchi's model and Korsmeyer–Peppas model (power law model). The porosity of the 3D printed scaffolds was assessed by SEM and, finally, the cellular response of each scaffold on the viability of CDD human fibroblast cells was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The sol–gel synthesis produces FHA, used in the realization of the scaffolds. The scaffolds have mixed porosity (macropores and micropores) promoting cell adhesion and proliferation, as shown by the results of the MTT assay. The addition of GO decreases the cell viability but keeps the scaffolds still biocompatible, and adding both DOX and GO to the FHA/PLA scaffolds has a negative impact on cell viability because DOX and GO remain toxic at the given percentages. © 2025 Society of Chemical Industry.

The production of easily separable and recoverable photocatalytic materials remains a critical challenge in achieving sustainable photocatalysis. Here, we have created a hybrid material consisting of photocatalytic polymers encapsulating magnetite nanoparticles. These nanoparticles exhibit excellent performance in oxidative hydroxylation of both boronic-acid- and boronic-acid-pinacol-ester-containing substrates. Moreover, these nanoparticles can be easily recovered and regenerated from the reaction medium via a simple magnetic separation technique. Extremely high efficiency has been maintained over multiple cycles, by recycling the magnetic photocatalyst. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The flame-retardant modification of plant fiber-reinforced composites (PFRCs) is a fundamental requirement for achieving broader industrial applications. However, commonly used modification methods often compromise the fiber mechanical properties or surface reactivity due to structural damage. In this paper, a water-soluble system consisting of phytic acid imidazole salt and biobased benzoxazine was devised to modify a regenerated cellulose fabric through water-phase immersion. Benefiting from the neutral solution and self-assembly coating, the modified fabric (F-RCF) exhibited a typical self-extinguishing behavior while maintaining good structural integrity and mechanical properties. By further combining F-RCF with a DOPO-containing epoxy resin blend (FEB) to prepare a fiber-reinforced green composite (F-RCF/FEB), the results indicated that the co-curing reaction between the modifier and resin matrix contributed to improved interfacial adhesion. This enabled the simultaneous enhancement of tensile modulus (from 9.82 to 11.29 MPa), impact strength (from 6.58 to 7.26 kJ m⁻²) and interlaminar shear strength (from 11.41 to 13.89 MPa). More importantly, F-RCF/FEB exhibited excellent anti-flammability in terms of a high limiting oxygen index value of 34.3% and a UL-94 V-0 rating, and the peak heat release and total heat release were also markedly reduced by 44.9% and 36.9%, respectively. Mechanism analysis revealed that the modified system effectively prevented the wick effect and provided an inhibitory effect in the gaseous phase, as well as a barrier effect in the condensed phase. This study presents a non-destructive modification strategy for plant fibers, which may also inspire the synchronous enhancement of interfacial compatibility and fire-proof performance of PFRCs. © 2025 Society of Chemical Industry.

Polyhydroxyalkanoates (PHAs) have been recognized as potential replacements for fossil fuel-based, non-biodegradable plastics. PHAs exhibit properties that are analogous to those of synthetic plastics. The production of PHAs offers a multitude of advantages, primarily due to their biodegradability and biocompatibility. The most naturally occurring form of PHAs are the polyhydroxybutyrates (P(3HB)s). The major limitations of P(3HB)s are their brittle nature and inferior mechanical properties. Hence, these biopolymers have been observed to have limited biotechnological applications. In contrast to P(3HB)s, copolymers of PHAs have almost all the desirable properties, making them suitable for high-end applications such as those in the medical sector. Structural modifications in PHA molecules have expanded the scope of their applications, including in medical implants, wound healing and bone grafts. It is noteworthy that considerable progress has been made in the field of PHA nanocomposites, which are now being explored for their biotechnological applications in drug delivery, tissue engineering and biosensors. The prospects for PHA nanocomposites are also summarized. © 2025 Society of Chemical Industry.

Microbial polyhydroxyalkanoates (PHAs) are biocompatible and biodegradable polyesters synthesized from biomass resources by various microbes in appropriate growth conditions as intracellular energy storage. PHAs have great biocompatibility, low immunological response, bioresorption, non-toxic degradation products and possibly resilient cell adhesion properties. Their mechanical characteristics can be modified to fit numerous tissues ranging from very soft (skin) to hard (bone). Multiple approaches have been used to create well-defined architectures with the best characteristics for processing as medical devices and biomedical application tools. The implementation of PHAs into medical devices as new functional materials with advanced 3D printing techniques has been described. Additionally, new challenges in improving PHA-based bioinks for creating scaffolds with enhanced biodegradation control suitable for tissue regeneration are also elucidated in this review. © 2024 Society of Chemical Industry.