Advanced Industrial and Engineering Polymer Research最新文献

The recent interest in multifunctional materials with tailorable performances led to the formulation of novel polymer blends, with enhanced properties with respect to traditional plastics and showing economical advantages compared to the synthesis of new polymers. However, polymer blends are immiscible in most cases, and proper compatibilization is therefore needed to obtain an alloy with suitable performances. Beside the traditional compatibilization approaches (i.e., addition of graft or branched copolymers, reactive compatibilization), a novel technique has recently emerged, based on the insertion of micro- and nanostructured inorganic fillers within polymer blends.

Therefore, the aim of this review is to give an overview about the role played by nanofillers on the compatibilization of polymer alloys. A survey of the most important papers in literature on this topic will be presented, trying to correlate the microstructural features of nanofilled blends to their physical properties. After an introduction on the general aspects of polymer alloys in Chapter 1, the most relevant compatibilization strategies will be presented in Chapter 2, with particular emphasis on the compatibilization induced by micro- and nanostructured fillers. Chapter 3 will be focused on the nanofiller induced compatibilization, and several examples of thermoplastic, thermosetting and elastomeric nanofilled blends will be presented. Considering the increasing importance of biopolymers and of their blends in the modern industry, in Chapter 4 it will be shown how nanofiller induced compatibilization could be successfully applied also to bioplastics based alloys. Due to the recent environmental concerns on the polymer waste management and the difficulties in the plastics sorting operations, in Chapter 5 it will be demonstrated that nanomodification of recycled plastics can lead to blend recyclates with good compatibility and suitable physical properties. The key aspects of the nanofiller induced compatibilization in polymer blends and the future perspectives will be summarized in Chapter 6.

Waste tires are a low-cost and high-calorific alternative fuel, therefore energy recovery is still very popular method of their utilization. On the other hand, waste tires are composed from high quality components and can be considered as valuable source of raw materials. Recent trends showed that further development of waste tire recycling technologies and waste tire rubber based materials are crucial to design the cradle-to-cradle loops for elastomer products. This approach fits to circular economy concept, however high content of waste tire rubber in various polymer blends or composites usually results in deterioration of their processing and/or the performance properties. Some of those technological issues can be resolved by choose suitable compatibilization method.

This work summarizes recent advances in the compatibilization strategies dedicated for polymer/waste tire rubber systems prepared via a simple melt-blending, including: i) optimization of processing conditions; ii) GTR particle size and oxidation; iii) devulcanization/reclaiming; iv) reactive blending and v) other methods. Furthermore, the limitations and challenges related to further development of thermoplastic composites and thermoplastic elastomers based on GTR are also highlighted.

The paper focuses on the necessity for compatibilization in polymer blends and composites due to the differing chemical nature of the components, which causes antagonism on the contacting surfaces. To achieve stable polymer blends and composites with the correct set of properties, this thermodynamically driven antagonism must be smoothed because it may result in dephasing. Typically, this is accomplished by including a third component, a compatibilizer. The review focuses on compatibilization strategies based on component peculiarities, that is, without the addition of a specially synthesized third component. They include the ability of components to participate in chemical interactions such as additional condensation and transreactions, hydrolytic reactions or hydrogen bonding, or the production of co-crystals and transcrystalline layers. Finally, single polymer composites are discussed as a case where compatibilization is not required.

This paper explores the potential of using Chat Generative Pre-trained Transformer (ChatGPT), a Large Language Model (LLM) developed by OpenAI, to address the main challenges and improve the efficiency of the Gcode generation process in Additive Manufacturing (AM), also known as 3D printing. The Gcode generation process, which controls the movements of the printer's extruder and the layer-by-layer build process, is a crucial step in the AM process and optimizing the Gcode is essential for ensuring the quality of the final product and reducing print time and waste. ChatGPT can be trained on existing Gcode data to generate optimized Gcode for specific polymeric materials, printers, and objects, as well as analyze and optimize the Gcode based on various printing parameters such as printing temperature, printing speed, bed temperature, fan speed, wipe distance, extrusion multiplier, layer thickness, and material flow. Here the capability of ChatGPT in performing complex tasks related to AM process optimization was demonstrated. In particular performance tests were conducted to evaluate ChatGPT's expertise in technical matters, focusing on the evaluation of printing parameters and bed detachment, warping, and stringing issues for Fused Filament Fabrication (FFF) methods using thermoplastic polyurethane polymer as feedstock material. This work provides effective feedback on the performance of ChatGPT and assesses its potential for use in the AM field. The use of ChatGPT for AM process optimization has the potential to revolutionize the industry by offering a user-friendly interface and utilizing machine learning algorithms to improve the efficiency and accuracy of the Gcode generation process and optimal printing parameters. Furthermore, the real-time optimization capabilities of ChatGPT can lead to significant time and material savings, making AM a more accessible and cost-effective solution for manufacturers and industry.

The sustainable processing of recycled products requires veritable testing during quality control for commercial application. In this research work, mechanical (ASTM D3039), compression (ASTM D5467) and impact (ASTM A370) are utilized to observe the usability, diversity, and suitability of the developed polypropylene-postconsumer cotton fibers (PP-PCCF) composites for industrial applications. The cotton waste was ground using a grinding machine. The ground fibers were introduced to manufacture composites from 0 to 40% fiber loading variations. The fine cotton fibers and synthesized composites were characterized by scanning electron microscope before and after mechanical testing. The fiber length, diameter and area were in the range of 2.5 mm–5.5 mm, 12.5 μm–22 μm and 200.15 μm²–250.50 μm², respectively. The engineering and design values were tensile strength (31.16 MPa–22.77 MPa), breaking strength (26.69 MPa–22.77 MPa), modulus of elasticity (2223.79 MPa–2770.77 MPa), and extension (17.48–3.21). Similarly, flexural strength, modulus, energy, and fracture force are also enhanced with an increase in fiber loading. The impact energies of pure polypropylene and PP-PCCF composites (with 10, 30, and 40% PCCF contents) were 50 kJ/m², 48 kJ/m², 43 kJ/m², and 58 kJ/m². The micrographs of PP-PCCF composites prove that the density of voids is enhanced with an increase in fiber contents. The PP-PCCF composites with 0%–30% fiber loadings showed minimum defects and were observed to be suitable for structural applications. On the other hand, the PP-PCCF composites with 30%–40% fiber loading are acceptable for environmental applications.

The treatment of wastewater requires the use of eco-friendly and cost-efficient adsorbents. A hybrid adsorbent film based on biodegradable polymers (poly(vinyl alcohol) (PVA) and chitosan (Ch) was developed to remove Acid Orange 7 (AO7), an azo dye from the textile industry present in industrial wastewaters. The polymeric absorbent material was submitted to a curing process with different time-temperature combinations which improved its physical stability in aqueous media. This result was supported by modulated differential scanning calorimetry (MDSC) and thermogravimetric analysis (TGA). ATR-FTIR also confirmed the electrostatic interactions by hydrogen bonds between PVA and Ch, as well as among the polymers and the dye. The best curing condition to reach a high removal without weight loss was the combination of 160°C-1h.

Dye adsorption depended mainly on pH, adsorbent dose, contact time, temperature, and coexisting anions. The maximum removal efficiency (>91%) was achieved at pH = 2.5. The adsorption kinetics followed the Lagergren pseudo first-order rate equation and the adsorption isotherm was best described by the Redlich-Peterson model. As far as the authors know, the maximum adsorption capacity (Q_m) of the adsorbent film obtained in the present work is the highest value reported in literature (Q_m = 678 mg/g at 298 K and pH = 2.5). Physisorption would be the dominant mechanism at pH 4.0 while at pH 2.5 the process was conducted by chemisorption. Regeneration studies showed that composites could be used for five consecutive cycles without losing their adsorption capacity.

Thus, the use of the developed eco-compatible biodegradable materials would allow easy regeneration without losing removal selectivity, a key feature in the development of environmentally friendly sorbent materials.

The development of innovative coatings with advanced multifunctional properties can lead the way to a more sustainable future. During the last decade, the global use of solar energy has been accelerating while there is a growing need for more energy-efficient buildings. Recent research efforts have focused on developing smart coatings that can rectify and amplify the role of protective glass surfaces which are mainly used in photovoltaic panels and in building windows. These surfaces suffer from the deposition of dirt, which compromises the power output of photovoltaic panels and stains the building facades. The application of novel self-cleaning, antifouling coatings on these surfaces can offer a proactive solution. Many research groups have suggested the use of antireflective coatings that can improve the transparency of glass, as well. Furthermore, the concept of radiative cooling coatings has been gaining attention as a method to lower the operating temperature of solar panels and to improve the temperature management of indoor spaces. In recent years, many hybrid polymer-based coatings have been proposed for these purposes, and the goal of this review is to summarize them and to assess their performance. The first part of this article is concerned with the selection of materials and the manufacturing processes. The second part is focused on the properties of these coatings, namely their optical transparency, their self-cleaning ability, their antireflective and radiative cooling performance, as well as their mechanical and chemical durability. The connection between the selection of materials, the coating formulation and the desired properties will be highlighted. Finally, future directions in this research field will be proposed.

Waste rubbers are environmental pollutants that could not be easily recycled. Devulcanization (i.e. as a reverse process of rubber vulcanization) is considered as a promising method for recycling of rubber wastes. In this study, a simple and effective chemo-mechanical devulcanization for waste nitrile rubber (WNBR) was introduced and compared to the mechanical, thermo-chemo-mechanical and radio-chemo-mechanical methods. The mechanical stress was applied to crumbed waste rubbers using a two roll mill in presence of different chemical agents (i.e. N-cyclohexyl-2- benzothiazole sulfonamide (CBS), tetra methyl thiuram disulfide (TMTD), diphenyl disulfide (DPDS), VitaX and a mixture of VitaX and DPDS). The sheet formation time on two roll mill, crosslink density (CLD) and sol/gel contents of waste rubber powders were measured before and after devulcanization. The devulcanized rubbers were characterized using TGA, DSC and GPC analysis. Finally, the properties of devulcanized nitrile rubber (i.e. the tensile, hardness and curing properties) were evaluated and compared to pristine NBR. It was found that VitaX is the most efficient chemical agent among the chemical agents. It caused 43, 87 and 98% decrement in the sheet formation time of chemo-mechanically, thermo-chemo-mechanically and radio-chemo-mechanically devulcanized samples compared to the mechanically devulcanized NBR, respectively. The samples also showed 24, 33 and 100% increment in the sol content, devulcanization percent and tensile strength compared to the mechanically devulcanized NBR, respectively.

Shape memory polymers (SMPs) are a class of smart materials that can be programmed to recover from temporary shape to permanent shape by applying external stimuli (temperature, magnetic field, light, electric field, and moisture, etc.). This unique property of SMPs makes them an appealing candidate in application for soft robotics, such as smart actuators, artificial muscles, and biomedical devices. In this contribution, we have developed multi-stimuli-responsive SMPs from bio-based benzoxazine resin and iron oxide nanoparticles (Fe₃O₄ NPs) that could be actuated by magnetic field and light. The nanocomposites were characterized by infrared spectroscopy, in which molecular interaction between benzoxazine/epoxy copolymers and Fe₃O₄ NPs was observed. Effects of nanoparticle content (0–5 wt%) on magnetic, mechanical, thermal, and thermo-mechanical properties of nanocomposites were investigated. Shape memory performance of nanocomposites was significantly improved with incorporation of Fe₃O₄ NPs. Shape fixity increased from 85% of neat copolymers to 93% of copolymers filled with 3 wt% Fe₃O₄ NPs, while shape recovery increased from 94% to 98%. Moreover, shape fixity could be done without external force contact by 808 nm-light actuation and magnetic attraction, due to photothermal and magnetic properties of nanocomposites. Shape recovery was tested under actuation by magnetic field. The highest shape recovery ratio was 99% within 26 s for copolymers filled with 5 wt% Fe₃O₄ NPs. Lastly, preliminary application of nanocomposites was demonstrated as they could push a 1 g-object within 10 s of actuation by magnetic field. In overall, these nanocomposites with multi-stimuli-responsive shape memory property had a good potential to be applied for soft robotics.

In this research, the manufacturing of completely biodegradable composites with a unique single-step sheet consolidation method was discussed. Layers of unidirectional, coarse twill, and fine twill flax; and poly lactic acid (PLA) were used as the material system to manufacture cylindrical and spherical composite half-shells. The three processing parameters were vacuum pressure, temperature and time. Thickness, mass fraction, tensile strength, shear strength, shape conformance and biodegradability of the manufactured composites were experimentally determined. The composite specimens’ cross-sections were also observed under an optical microscope, to assess, the consolidation quality of the manufactured composites, that was represented by the composite thickness, and primarily governed by the polymer viscosity, and the transverse and in-plane fibre reinforcement permeability. Biodegradable Flax-PLA composites were successfully consolidated, within 5% tolerance of the targeted mass fractions and thickness values, conforming within 8% tolerance to the shape of the mould. The highest achieved shear strength, flexural modulus, tensile strength and elastic modulus, were 22 MPa, 19.9 GPa, 179 MPa and 19.5 GPa, respectively. This research will be valuable to develop, flat and curved biodegradable composites, for one-off or small scale productions, at a relatively low capital cost.