Advances in Polymer Technology最新文献

This work presents a novel semiempirical mathematical approach consisting of a coupled thermo-kinetic model as valuable tool for predicting the polymeric fraction profile of membranes synthesized by nonsolvent induced phase separation (NIPS). Equilibrium binodal curves (BCs) of the system component were incorporated to the Fick’s diffusive kinetic model allowing a satisfactory prediction of the tendency to develop symmetric or asymmetric porous membrane morphologies, as well as a fair quantification of average porous fraction profiles. The model was validated using two different ternary systems: (i) polycaprolactone (PCL)/N-methylpyrrolidone (NMP)/water (W) characteristic of instantaneous demixing (asymmetric finger-like porous cross-section morphology); and (ii) PCL/NMP/isopropanol (IPA) characteristic of delayed demixing (symmetric sponge-like cross-section morphology). The loading of graphene oxide (GO) in the quaternary system PCL/GO/NMP/IPA also gave rise to a sponge-like porosity, characteristic of delayed demixing systems, which was reasonably predicted by the coupled thermo-kinetic model developed in this study. In addition, a computational scanning electron microscopy (SEM) image processing methodology was developed to validate the thermo-kinetic model, resulting in an advantageous tool for that purpose. Overall, this work reveals the usefulness of the new thermo-kinetic mathematical approach as a facile computational tool for membrane manufacturers and researchers for a preliminary discrimination of component combinations in quaternary polymer/nanofiller/solvent/nonsolvent NIPS systems.

In this study, we investigated the process of obtaining dialdehyde carboxymethylcellulose (DCMC) with a high molecular mass and aldehyde content (AC) through periodate oxidation under microwave irradiation. We examined the effects of periodate oxidation time, sodium periodate (NaIO₄) concentration, and pH value of the solution under microwave treatment on the molecular mass, aldehyde group content, and yield of DCMC. Optimal conditions for the periodate oxidation reaction under microwave irradiation (microwave power level set at 10% or 70 W) were identified as follows: a reaction time of 10 min, oxidant concentration of 2.5% (with a molar ratio of carboxymethylcellulose to NaIO₄ of 1:1), and pH of 3.5. Under these conditions, the oxidation degree of DCMC obtained by microwave treatment was 82%, with a molecular mass of 141 kDa, a polydispersity of 1.4%, and a product yield of 70%. The obtained samples were analyzed using a variety of methods including chemical analysis, FTIR spectroscopy, thermogravimetric analysis, atomic force microscope (AFM), and nuclear magnetic resonance (NMR) spectroscopy.

This article presents a review of achievements in the research aimed at improving the main building material—concrete—along with its physical, mechanical, and operational properties. As is well known, in the near future, the role of concrete will continue to be primary in the construction of buildings and structures due to increasing demand. However, despite its advantages, this important building material is not without flaws. In particular, due to its porosity, concrete is highly permeable to liquids, making it insufficiently resistant to frost and corrosion and sometimes even brittle. At the same time, concrete mixtures used in modern construction must meet requirements such as good adhesive properties, improved waterproofing, high workability, retention of rheological characteristics over time, and the potential for increased strength. Today, the use of polymer additives as modifiers to improving concrete is particularly relevant. The purpose of this review is to examine recent advances in understanding the impact of polymer additives of both inorganic and organic nature on improving concrete properties. Continued research in the field of polymer modifiers and exploration of new research opportunities are for engineering advancements and the development of modern materials.

With a deeper understanding of the aging process, injectable dermal fillers have revolutionized cosmetic dermatology and plastic surgery. These minimally invasive treatments address signs of aging, such as wrinkles, fine lines, and volume loss. The market for injectable dermal fillers expands yearly, with each product offering unique compositions that influence therapeutic outcomes, handling properties, and potential adverse effects. Fillers are generally classified into three major types: temporary, semi-permanent, and permanent. Temporary fillers, including hyaluronic acid (HA) and collagen (COL)-based options, provide reliable correction but typically have limited longevity. Semi-permanent and permanent fillers, made from synthetic materials like poly-L-lactic acid and polymethylmethacrylate (PMMA), offer extended durations of neocollagenesis. This review focuses specifically on COL-based fillers, discussing both FDA-approved products and those still in the research stage.

Polybenzoxazole (PBO) paper, made of PBO chopped fibers and PBO fibrids, is used in many cutting-edge fields because of its excellent properties. The rigid molecular structure makes PBO only dissolved in strong acids such as fuming sulfuric acid and polyphosphoric acid at a very high temperature. Due to the harsh preparation conditions, it is not easy to industrialize PBO fibrids. Herein, a two-step method was used to prepare the PBO paper. Firstly, polyhydroxyamide (PHA) was synthesized in an organic solvent and used to prepare fibrids, and the PHA paper was then prepared using PHA fibrids with a traditional wet papermaking process, and the obtained PHA paper was further converted into PBO paper by thermal cyclization. The results show that the PHA fibrids have a high length–diameter ratio, film shape, and abundant hair structure, and the tensile index of the PHA base paper is as high as 123.3 N·m/g. After thermal cyclization, the structure and morphology of the paper have little change, and the mechanical properties of the paper have a certain loss. However, it is still much higher than that of PBO paper prepared directly from PBO fibrids and has excellent thermal stability, so it is suitable for preparing high-temperature-resistant paper-based composites.

The findings suggest that rolling is a potentially effective technique for commercial applications in industries requiring high-performance polymer films. The solid-state rolling process is well-established for semicrystalline and amorphous polymers, but its application to segmented, two-phase polymers like thermoplastic polyurethane (TPU) which features physically cross-linked systems and excellent physical and mechanical properties, remains underexplored. This study aims to investigate the rolling of TPU under various conditions to address viscous relaxation and achieve maximum thickness reduction, producing thin sheets. The rolling characteristics were assessed by measuring the thickness changes of rolled specimens of two TPUs with different hard phase fractions, alongside thermoset polyurethane (PUR) with chemical cross-linking for comparative analysis. The results showed that the TPUs exhibited little plastic deformation at room temperature. The cold rolling test, conducted at a rolling speed of 0.5 m min⁻¹ with a nominal reduction of 85%, indicated that the permanent reduction ratio was less than 35% for both TPUs. However, when the rolling speed was increased to 3 m min⁻¹, the permanent reduction ratio increased to 67% and 60% for TPU ShA90 and TPU ShA85, respectively. This result indicates that at high rolling speeds, the thermal condition tends to change from isotherm to adiabatic in the rolling test. The maximum reduction ratio of 70% was achieved at a nominal reduction of 85% for TPU ShA90 at higher rolling temperatures and speeds.

In recent years, the drive to adopt sustainable practices and develop eco-friendly processes and products has gained significant momentum in the global polymer industry. A key component of this shift is the increased use of recycled materials, which not only align with environmental goals, but also offer considerable economic advantages. Integrating post-consumer recyclates (PCRs) into manufacturing processes, particularly in injection moulding, holds great potential for reducing CO₂ emissions, decreasing reliance on virgin materials, mitigating waste and promoting a circular economy. Nevertheless, a switch to 100% recyclate has not yet been effective or economical in many areas of application, so mixtures of virgin and recyclate material represent a promising approach and must be analysed further. Therefore, this study examines the impact of different virgin/recyclate-mixture ratios on both injection moulding process stability and resulting part quality, focusing on high-density polyethylene (HDPE) and polypropylene (PP) blends. For this purpose, virgin/PCR mixtures are compounded, rheologically analysed using high-pressure capillary rheometry and processed via injection moulding. The process data are analysed, and the produced parts are mechanically and geometrically evaluated. The findings show that for PP, an increasing recyclate content results in a nearly linear improvement in tensile strength and modulus of elasticity without significantly affecting material viscosity, ensuring stable processing conditions. However, part warpage increases with higher recyclate content. In contrast, for HDPE, a higher recyclate content decreases the mixture viscosity, leading to decreased injection pressure and dosing torque during processing. Despite this, the tensile strength and modulus of elasticity improve, while part warpage decreases for HDPE. For both materials, though tensile strength and elasticity increase, higher recyclate contents negatively affect fracture behaviour, as evidenced by breakage patterns and strain at break. The study also demonstrates that the linear mixing rule can be applied to process parameters and part geometry characteristics for virgin/recyclate mixtures, facilitating the integration of recyclate content into product development.

Currently, the world is undergoing the fourth industrial revolution, also referred to as Industry 4.0, which is characterised by a set of new technological advances in the industrial and production sectors. Additive manufacturing (AM) is considered an essential factor in this new era because of its ability to process a wide spectra of materials, produce customised products, promote sustainability and develop intricate components which are unachievable using conventional manufacturing techniques. The field of AM is rapidly evolving and has seen unprecedented uptake in many industries. Different types of AM technologies have been developed over the last three decades to process different materials, such as polymers, composites, metals, ceramics and alloys. Both industry and academia have made a considerable effort to investigate the use of AM technologies to print different types of polymers because of the possibility to reach new markets. This comprehensive review focuses on polymer laser sintering (PLS) and fused deposition modelling (FDM), which are the most commonly employed AM methods for polymers. This review outlines the processes, process parameters, available commercial polymeric materials, benefits, challenges, and applications of the two technologies. PLS and FDM are multifactorial processes that produce final components whose quality is subject to the process parameters. This review, therefore, delves into the different process parameters for the two technologies and their impacts. The article also lists the available commercial polymeric materials, for each of the methods, to assist researchers and industries to select most suitable materials based on their processability and characteristics. A detailed discussion of applications of the two technologies is outlined in this review. The study provides a comprehensive detail of the benefits and challenges of PLS and FDM. Last, the study also outlines the future works for the two techniques.

The quest for efficient and sustainable energy storage solutions has prompted exploration into advanced materials that meet stringent mechanical and thermal requirements. This study investigates graphene-reinforced thermoplastic polymers specifically polyether ether ketone (PEEK), polyethylene terephthalate glycol (PETG), and polylactic acid (PLA) fabricated through additive manufacturing techniques. Traditional materials often suffer from limitations in structural integrity, flexibility, and thermal stability, presenting challenges for their application in energy storage. This research aims to evaluate the mechanical properties of these graphene-reinforced polymers to assess their suitability for energy storage components. Using additive manufacturing, test samples were fabricated, and mechanical testing was conducted to evaluate tensile, flexural, and compression strengths. The results indicate that graphene-reinforced PEEK (G-PEEK) exhibits superior mechanical performance, with an ultimate tensile strength of 120 MPa, Young’s modulus of 1700 MPa, ultimate flexural strength of 160 MPa, and ultimate compression strength of 200 MPa, making it an ideal candidate for applications requiring high structural integrity. Graphene-reinforced PETG (G-PETG) offers a balance of strength and flexibility, with an ultimate tensile strength of 55 MPa, while graphene-reinforced PLA (G-PLA) serves as a cost-effective option, despite lower mechanical properties (ultimate tensile strength of 45 MPa).

Polyolefins such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP) are among the most widely used packaging materials in the cosmetic industry. Since these materials are in direct contact with cosmetic products, various components of the products are adsorbed to the packaging material’s surface and migrate within the amorphous regions of the polyolefin. This migration process, which occurs in both virgin and post-consumer recyclate (PCR) materials, can lead to deformation of the packaging. In this study, different types of virgin and PCR pellets were examined to investigate their interaction with cosmetic products and to understand the factors influencing the migration process. The migration of cosmetic oils was observed in all pellet samples, depending on the composition of the product and environmental conditions. The process was characterized by the weight gain of the plastic pellets and further identified through nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. Additionally, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) measurements were performed to analyze the polymer structure. Components with lower molecular weight (MW), high nonpolarity, and elevated temperatures were found to accelerate the migration process. Moreover, migration occurred more slowly from oil-in-water emulsions with larger droplet sizes compared to water-in-oil systems with smaller droplets. Among the different polyolefins, PP demonstrated a higher uptake of migrating components but at a slower migration rate compared to HDPE and LDPE. When comparing virgin and recycled polyolefins, it was observed that migration was consistently slower in virgin materials than in recycled ones. The ability of oils to migrate is influenced by the molecular structure of the polymers: high density, crystallinity, and low levels of branching reduce both the migration speed (MS) and the maximum saturation, as seen in virgin HDPE. In contrast, materials like LDPE, with a less dense polymer structure, exhibited higher MSs and saturation limits. As a control, polyethylene terephthalate (PET) was used, and it showed no migration due to the polymer’s high density.