Advanced Industrial and Engineering Polymer Research最新文献

The exhaustion of available natural resources and rising concerns about the environment have prompted a growing desire to discover innovative ways to produce environmentally friendly materials. In an effort to alleviate environmental issues connected to the disposal of agricultural waste, many studies have engaged on research pertaining to agricultural waste management. Every year, there are enormous amounts of agro based waste created, which is a major issue from an economic and environmental standpoint. These wastes can be utilized as secondary raw materials to create value-added products in accordance with the circular economy's guiding principles. The exploitation of natural agricultural wastes has become critical for the development of sustainable biopolymer-based composites for lightweight applications. To this extent, this review presents an overview of the development and utilization of agricultural wastes to create biopolymers building blocks to be coupled with natural reinforcements for the fabrication of sustainable bio composites for lightweight applications. Common agricultural derived biopolymers are discussed. This review also highlights major bio composite fabrication methodologies and potential applications including challenges and opportunities in the development of sustainable biopolymer-based composites from agricultural waste biomass. It was concluded that the development of sustainable biopolymer-based composites from agricultural biomass offers a promising route towards a more environmentally friendly future.

Magnesium (Mg) & its alloys are favourable for orthopaedic & cardiovascular medical device fabrication applications, but holds a natural ability to degrade biologically when put with aqueous solution of the substances and/or water-saturated tissue in the context of a living organism. Mg alloys nature to corrode inside the living organism body is mainly attributed to the excessive rates of corrosion of Mg. Poor corrosion resistance possessed by Mg decreases the mechanical properties of the implants, and adds toxic effects on the bone metabolism. A potential method for increasing Mg alloy resistance to corrosion without changing its properties is by the protective polymeric deposit coatings. Moreover, to impart better mechanical and biocompatible aspects to Mg based materials biopolymers have been used as a composite constituent. This review is based on such composite materials constituting Mg and biopolymers. Their resulting favourable mechanical and osteopromotive properties in conjunction with biocompatibility may help the clinicians to fix the existing orthopaedic related issues.

Due to the deleterious environmental consequences resulting from a broad spectrum of synthetic polymers during use or post-application disposal, interest in biomaterials obtained from eco-friendly and sustainable sources is growing. This review first examines some of the fundamental concepts regarding biologically-derived nanoparticles (“bionanoparticles”) extracted from the two most prevalent polymers on the planet: natural cellulose and chitin. With this background established, we turn our attention to several advances in this expanding field. Recent rheological studies have established that a “kink” often reported in steady-shear tests of fibrous nanocellulose suspensions is related to anisotropic flocs. Thorough analysis of this observation demonstrates the existence of dual yield points that pinpoint the processing conditions over which these flocs form. Another advance is isothermal titration calorimetry, which relates the formation of structure to viscous heating and provides a uniquely quick and precise analysis tool for measuring the concentration of cellulose nanocrystals responsible for the onset of mesomorphism in aqueous suspensions. In addition, the incorporation of various electrolytes in aqueous nanocellulose or nanochitin suspensions is capable of promoting cellulose or chitin nanocrystal (de)swelling or suspension templating of solid films, and positron annihilation lifetime spectroscopy can be used to follow changes in nanoscale free volume upon swelling in the presence of moisture, which can be independently used in conjunction with CO₂-philic ionic liquids to achieve highly selective carbon capture in hybrid gas-separation membranes.

Polymer-based drug delivery systems have been extensively studied for decades. These systems must be degradable, capable of controlling drug release kinetics, and of reaching a precise target organ. While degradability is an intrinsic property of the material, controlled and targeted drug delivery is achieved with proper system design. The Molecular Imprinting technique can be used successfully to control the drug release kinetics and to achieve drug targeting. To date, the literature reports a very limited number of studies related to molecularly imprinted polymers for nanomedicine. The lack of applications is mainly due to the difficulties of obtain degradable materials with this technique. The present review reports a summary of the applications and characteristics of molecularly imprinted polymers, with a focus on their potential in nanomedicine. The advantages of their use and any limitations will be highlighted. Finally, the applications of the molecular imprinting technique, developed so far, to the preparation of degradable materials will be reported.

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 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.

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.

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.

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.