Advances in Polymer Technology最新文献

Rubber mixing is an important link in the production of rubber products. Computational fluid dynamics (CFD) simulation is often used to explore the effect of rubber mixing parameters on rubber mixing effect. Previous CFD-based rubber mixing simulation studies did not consider the impact of using 2D or 3D numerical calculation models on the numerical simulation results. In order to investigate the differences between 2D and 3D numerical computational models in rubber compounding CFD simulation problems, in this paper, we compare and analyze the results obtained from 2D and 3D computational models under different rotational speed conditions to investigate the differences between the models in the numerical simulation of rubber compounding. Three different experimental speeds of the rubber mixer—39, 44, and 49 r/min—were set during the study using 2D and 3D asynchronous rotor models with a speed ratio of 1.15, respectively. The rubber was processed using the Bird–Carreau model. The phase interface between rubber and air was calculated using the volume of fluid (VOF) method. The numerical simulation results of different models show that the rotational speed set to 49 r/min shows the best dispersion distribution effect; the mixing effect and speed change rule obtained by the 2D model are consistent with the results obtained by the 3D model. The performance of the results of the two models is consistent when exploring the numerical simulation of rubber compounding.

The shape memory (SM) polymers with superior SM properties were successfully fabricated based on melt blending of natural rubber (NR) and ethylene octene copolymer (EOC) at various crystallinity of EOC phase. The differential scanning calorimetry analysis, mechanical properties, temperature scanning stress relaxation, and shape memory properties were studied. Results revealed that the mechanical and thermal properties of the prepared NR/EOC blends improved as a function of amount of ethylene fraction in the EOC phase. The ethylene segment of EOC in the NR/EOC blend is triggered as a stimulus-sensitive domain. The shape memory properties in terms of shape fixity and shape recovery efficiencies of the blends tended to increase with the increasing of crystalline segments in the blends. The shape memory properties of the prepared blends substantially exceed the best performance (close to 100%) by blending the NR/EOC at 50/50 parts by weight, having 62%–80% of ethylene content in the EOC phase, which corresponds to approximately 3°–16° of crystallinity of EOC phase in the blends.

Chirality is one of the most common and significant phenomenon in nature, and epoxy resin is one of the most widely used and researched thermosetting resins, however the influences of chiral carbon in epoxy group on the performances of the cured epoxy resins have ever been hardly studied, therefore it is crucial and meaningful to explore the structure–function relationship of chirality and performance of epoxy resins. Herein, from the analysis of synthesis mechanism, the different chiral configuration with high percent enantiomeric excess (>99%) and racemic bisphenol A epoxy resins were simply prepared by controlling the chirality of epichlorohydrin. The apparent activation energy of the curing process with D230 was calculated by Kissinger method and Flynn–Wall–Ozawa method, respectively, and both results indicate that chirality have no effect on the curing reaction. We found that the secondary structure of epoxy monomer is untouched by its chirality, and they are all right helix structure. For this reason, the thermal stability, glass transition temperature, and thermomechanical properties of diverse chiral epoxy resins cured by D230 have no significant difference. Nevertheless, it was found that the optical rotation activity of chiral epoxy resins can be partially maintained after curing reaction, it manifests the cured products of chiral epoxy resins possesses the possibility of application in the field of polarized materials.

The increasing concerns about solid waste disposal have led to the development of innovative strategies for repurposing waste materials. This paper describes a simple solution casting process for recycling postconsumed footwear leather fiber (PCF) into a biocomposite film reinforced with graphene oxide (GO) and polyvinylpyrrolidone (PVP). PVP was utilized as a compatibilizer to strengthen the interfacial bonding of GO and leather fiber via π–π interactions. UV–visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy were used to examine the material dispersibility bonding between GO and PCF, structural properties, thermal properties, and surface morphology of the biocomposite films, respectively. Compared to pure PCF film, the oxygen transmission rate of the prepared biocomposite films is elevated by 64% as well as the biodegradability rate is intensified up to 60%. In addition, the film’s tensile strengths are raised by 216%, while their elongation at break is increased by 164.64% as compared with PCF. The versatility of these eco-friendly and biodegradable composite films extends to its possible applications in packaging and interior design. The outcomes of the research reveal the viability of manufacturing affordable and sustainable biocomposites through the utilization of waste leather from consumed footwear.

Polyethylene terephthalate (PET) is one of the most widely used plastics in the world. Due to the large production and use of this plastic, its waste represents one of the most critical environmental problems. The purpose of this study is to convert PET waste into a valuable material. The consumed PET was transformed into a precursor to synthesize a polyionic liquid (PIL) that was used for dehydrating crude oil emulsions. To do so, the consumed PET was converted to bis(2-hydroxyethyl) terephthalate (BHET). First, BHET and tetraethylene glycol were reacted separately with thionyl chloride, obtaining the corresponding alkyl halides, bis(2-chloroethyl) terephthalate, BCET, and TEC, respectively. Next, the obtained alkyl halides, BCET and TEC, were reacted with 1,5-pentanediamine, yielding a polymer (BTP). Finally, BTP was reacted with acetic acid to produce the corresponding PIL (BTP–PIL). The structure and thermal stability of BTP–PIL were characterized using nuclear magnetic resonance spectroscopy and thermal gravimetric analysis. The dehydration performance of PIL and the original polymer was investigated using the bottle test method, including several factors such as demulsifier dose, brine content, temperature, and settling time. Results indicated that PIL achieved high performance in dehydrating crude oil emulsions.

Ultrahigh molecular weight polyethylene (UHMWPE) fiber is widely recognized for its exceptional properties, including high strength-to-weight ratio, toughness, and chemical resistance, making it a preferred material for reinforcement in various applications. However, its low melting point, surface inertness, and weak adhesion to polymer matrices have limited its potential use in some fields. Researchers have addressed these shortcomings by focusing on surface modifications through physical treatment or chemical coating, thereby enhancing the versatility of materials in numerous UHMWPE fiber composites. By improving the tribological and interfacial properties of UHMWPE, various applications can be explored, including prosthetic joints, energy-absorbing road safety systems, microelectromechanical system devices, and protective materials for defense and personal thermal management. This review provides a comprehensive overview of the remarkable performance of UHMWPE and its composites, providing insights into its wide array of applications.

In addition to being a lipid-lowering medication, atorvastatin (ATV) is an anti-inflammatory agent. When there is a bone defect or inflammation of adjacent tissues, it aids in bone repair. This study aimed to develop a chitosan–alginate (CS/ALG)–tripolyphosphate (TPP)–ATV hybrid hydrogel as a drug delivery system, using a tissue engineering scaffold for the first time. For this purpose, a CS/ALG hydrogel crosslinked with TPP was developed. The delivery profile of ATV and its physicochemical properties such as particle size and hydrogel swelling percentage were determined. The structure and morphology of the hydrogels were analyzed using Fourier transform infrared spectroscopy and scanning electron microscopy. As a result, an alginate–chitosan hydrogel with a TPP crosslinker was prepared. The results revealed that drug loading was nearly complete, and the first hour revealed a 25% explosive release. The drug was gradually released over 10 hr at approximately 35%. The amount of crosslinker used significantly influenced the encapsulation gain and release profiles. Owing to its high porosity and swelling, the CS/ALG hydrogel crosslinked with PPT is an ideal scaffold for loading drugs, macromolecules, and cells.

The additive manufacturing (AM) of elastomeric parts based on high-viscosity reinforced rubbers has increasingly become a topic of scientific research in recent years. In addition to the viscosity, which is several decades higher during processing than the viscosities of thermoplastics, the flowability of the compound after the printing process and the necessary chemical crosslinking of the printed component play a decisive role in producing an elastic, high-quality, and geometrically stable part. After the first technological achievements using the so-called additive manufacturing of elastomers (AME) process, the knowledge gained has to be transferred first to concrete industrial parts. Therefore, in this study, the cure kinetics of a conventional rubber compound are tailored to match the specific requirements for scorch safety in the additive manufacturing of an industrial 2-component rod seal based on an acrylonitrile butadiene rubber O-ring in combination with a thermoplastic polyurethane as the base body. Experimental tests on a test rig for rod seals demonstrate the functionality of this additively manufactured 2-component rod seal.

Ultra-high-performance fibre-reinforced concrete (UHPFRC) is a specialized type of concrete (to create a very dense matrix) that is used for both new construction and renovation projects in order to improve the lifespan of structures. Researchers analyse and evaluate only the microstructure, porosity, and fresh and hardened concrete properties of UHPFRC but limited their exploration on the reduction of the mechanical properties of UHPFRC due to the presence of metallic particles and micro-fractures that occur during the generation of hydrogen. Hence, the present study aims to eliminate the existing problem by hybridization approach (mixing of bio-nano-silica (nS) and polypropylene) with different percentages to further improve the strength properties of UHPFRC. The result showed that the compressive strength is increased by 15.5% compared to traditional concrete due to the filling ratio of nS in the pores of the concrete; in addition, the fibre’s surface and roughness also contributed to the strength enhancement.

Polymer matrix composites synthesized with biodegradable natural fiber obtain a predominant structure with specific properties at a low-processing cost. The unique characteristics of polymer matrix composites were magnetized in automotive parts like top roof, panel, and seat frame applications. American Society for Testing and Materials (ASTM) G99 analyzed the wear characteristics of synthesized composites through a pin-on-disc wear tester with an EN32 steel disc. The epoxy hybrid composites have been synthesized via a conventional casting process assisted with a mechanical interlock technique to obtain a predominant structure with specific properties at a low-processing cost. The advanced composite contained different jute weights (50, 25, 50, and 75 g) and coconut coir (50, 70, 45, and 20 g) hybridized with graphite particles. ASTM D2240, D638, and D790 standards evaluated the fabricated composite hardness, tensile, and flexural strength. The Sample 4 hybrid composite found maximum hardness, tensile, and flexural strength of 27.41 ± 0.99 Hv, 51.69 ± 1.01MPa, and 55.94 ± 0.78 MPa, respectively. Sample 4 offered good wear resistance of their volumetric wear rate of 0.043 cm³ on 40 N average load at 0.25 m/s sliding speed. It is increased by 12% compared to Sample 1 at 40 N applied load on 2.5 m/s sliding speed.