Advanced Industrial and Engineering Polymer Research最新文献

Understanding the external and internal factors during an additive manufacturing (AM) process is crucial, as they can significantly affect the final product's performance. Efforts have been made to unwind the product, process, property, and performance (PPPP) relationships. The conventional experimental approaches can lead to boundless runs, resulting in exorbitant costs for research and development. Hence, developing, adapting, and validating numerical models is essential to achieving the desired performance of 3D-printed products with lesser resource utilization. In this study, numerical and experimental techniques were used to perform the PPPP relationship assessment on material extrusion 3D-printed parts. Three infill designs (rectangular, triangular, and hexagonal), with layer heights (0.1 mm, 0.125 mm, and 0.2 mm), and three different materials (carbon fiber-reinforced polyamide-6 (PA6-CF), polyamide-6 (PA6), and acrylonitrile butadiene styrene (ABS)), were selected for the investigation. Taguchi's design of experiments (DOE) method was used to limit the number of numerical simulations and experimental runs. A thermomechanical numerical model was utilized to perform the material extrusion process simulations and mechanical performance prediction of the specimens. Subsequently, the samples were 3D-printed and tested mechanically to validate the numerical simulation results. The dimensional, distortion, and mechanical analysis performed on numerical simulation results agreed well with the experimental observations.

A bimodal impact strength distribution was found in notched impact specimens of HDPE composites with calcium carbonate, carbon black, SEBS and stabilisers. The bimodal distribution was only found at moderate-to-high calcium carbonate loadings, with the likelihood of low impact strength increasing with increasing stabiliser loading and decreasing with increasing SEBS/CB masterbatch loading. Bayesian methods were used first to confirm bimodality and then to investigate the effects of formulation on the performance of the system, based on a hierarchical model with quadratic and interactive terms and switching based on the sampling of a Bernoulli distribution with a logistic regression informing the probability of high or low impact strength. The results are contextualised through micrograph fractography and, briefly, differential scanning calorimetry. Results are also reported for unnotched impact tests, with negative correlations for impact strength with calcium carbonate and stabilisers, a positive correlation with SEBS/CB and interactive effects.

The brittle fracture pattern in plastics associated with low toughness performance have a negative effect on their performance especially for long-term and specialized applications. This review provides a comprehensive understanding of toughening mechanisms in polyethylene (PE) and the details of different techniques for achieving a balance between strength and toughness in PE-based composites. Various strategies for toughening, along with the parameters involved in processing and materials development, such as matrix chemical modification, use of a second phase, and incorporation of coupling agents are discussed in detail. Current challenges and future opportunities for simultaneous toughening and strengthening in PE-based composites are outlined for further research and development in academia and industry to expand the applications of PE composites, overcome current challenges, and provide useful insights for further advancements, particularly in the area of toughened composites.

Theoretical research has predicted high thermoelectric performance for bismuthene nanosheets, but it is a great challenge to prepare these nanosheets due to low efficiency and intensive oxidation. We herein report an efficient, environmentally friendly preparation method for bismuthene nanosheets, each being 1–1.5 nm thick in average, through mechanochemical treatment with an ethanol system. The system was found to prevent adverse oxidation in comparison with a pure water system. Although neither the oxidation reactions nor the exfoliation could significantly change the Seebeck coefficient of bismuthene nanosheets, their power factor was measured as 155.6 ± 15.4 μW·m^-1K^-2. An epoxy nanocomposite was prepared containing 99 vol% of bismuthene nanosheets, to create a thermoelectric generator. It converted a temperature gradient of 11°C generated by human body into an electrical output of 18.62 nW. Our mechanochemical exfoliation method for the preparation of low-oxidation bismuth nanosheets offers insights for large-scale fabrication of nanosheets and their composites for industrial applications. It advances the field of thermoelectric nanocomposites.

To develop metal-free magnetic resonance imaging (MRI) contrast agents, organic radical based contrast agents have been proposed as a promising alternative to obtain less toxic and safer MRI contrast agents. However, the low relaxivity and rapid in vivo reduction have limited the application of organic radicals as MRI contrast agents. As a special class of polymer, dendrimers with three-dimensional molecular structure and multiple tunable functional groups on surface, enable the facile chemical modification with organic radicals. With dendrimer as scaffold, a considerable amount of effort has been made to develop completely organic contrast agents. Herein, this mini review reports the recent advances of contrast agents with dendrimers as scaffold functionalized with radicals on the surface.

Highly ordered porous structures of PLA composite films can be designed with the addition of calcium carbonate nanoparticles (CCN) in polymeric film formation using the breath figure (BF) technique at controlled humidity. Both 2D and 3D monodispersed honeycomb-like porous structures of the PLA composite films are achieved by the adding CCN at the concentration of up to 1.00 phr, whereas hierarchically multiscale porous structures of the PLA/CCN films are obtained when the CCN concentration in the composites increases to more than 1.00 phr. These structures can be fabricated due to three mechanisms: water absorption and condensation, nano-Pickering emulsion, and capillary flow by self-assembly of the nanoparticles. Moreover, the nano effects of CCN on polymeric film fabrication are maximized by increasing the relative humidity to 90%, resulting in the formation of porous multilayers up to 95–120 μm in thickness. The application of the prepared porous composite films of PLA/CCN in the food and medical industries was illustrated. A model colorimetric sensor is made from PLA/CCN composite films enriched with bromothymol blue. The color of the films quickly changes from yellow to blue within 10 min after coming into contact with histamine, a representative gas generated from spoiled food.

Nowadays there are many attempts for sustainable development due to rapid industrialization. In this context, thymol and carvacrol, which are obtained from many plants, are highly promising components in many industries due to their multifunctionalities. However, their water insolubility, instability, and volatility are significant drawbacks that must be addressed. To overcome these issues, they are commonly incorporated into fibrous structures for applications in the food and human health-related industries. With advances in technology, thymol/carvacrol containing fibrous structures have been generated using various techniques, widening their applications in the related fields. While their anti-bacterial properties have been widely exploited in various applications, this review article covers their anti-oxidant, anti-inflammatory, anti-septic, anti-cancer, anti-microbial (anti-bacterial, anti-fungal, anti-biofilm, and anti-viral), anti-parasitic (insecticidal, anti-malaria, anti-acaricidal (anti-mite and anti-tick), anti-toxoplasmosis, and anti-leishmaniasis) properties, considering all the broadened applications of thymol/carvacrol containing fibrous structures. Ever-increasing food and human health-related incidences will accelerate the uttermost exploitation of all functionalities of thymol and carvacrol in multifaceted ways. Nanoscale containers and fibrous structures will be the pioneers for finding new and more effective applications of thymol and carvacrol. For example, they could find applications not only in packaging for market shelves but also in entire food chain, including plant protection in agriculture (pre-harvest and post-harvest), transportation, and storage of food/crop. Fibrous structures containing thymol/carvacrol will also enable new and diverse applications in hygiene & preventive care, comfort & well-being in addition to wound healing and tissue engineering in the human health. A detailed future perspective is provided related to all these applications.

Poly (lactic acid) (PLA) foams have demonstrated a high variety of functional characteristics, still, the rigidity of this cellular material remains a major limiting factor when it comes to implementation options. In this contribution, PLA foams with outstanding flexibility were created for the first time by a new approach of uniaxial stretching and immediate relaxation following supercritical CO₂-assisted extrusion foaming. Instead of improving the resilience of the PLA raw material, structural elasticity of the foam was achieved via altering the deformation mechanism from cell wall collapse or rupture towards reversible and extensive flexural strain. In addition, PLA foams with excellent piezoelectric properties were also achieved via high-voltage corona poling, giving additional function to the lens-like anisotropic foam cells. This foaming technology creates the opportunity to produce PLA piezoelectrets in a way entirely different from the state-of-the-art methods. Correlation between the tensile as well as compression elongations and moduli, cell morphology and longitudinal piezoelectric coefficients (d₃₃) of electretized foam samples were studied. Unprecedented reversible tensile elongations of up to 16% and total elongations of up to 35% were reached, as well as considerable d₃₃ values in the range of 50–320 pC/N were obtained for PLA ferroelectrets.

Recent developments in nanomaterials have come to extensive use in various fields, especially in the biomedical industry. Numerous significant obstacles still need to be overcome, particularly those about utilizing nanomaterials in biomedical science, before they can be used for medicinal purposes. Major issues in biomedicine include biological functioning, harmony, toxic effects, and nano-bio surface properties. Thus, researchers may use cutting-edge characterization approaches to study nanomaterials for biomedical applications. Two-dimensional nanomaterials and polymers are crucial components of biological systems. Polymer-based nanomaterials are flexible and more resistant to chemical attack than other NPs. Polymers easily form composite or functionalization with other NPs to improve their performance compared to the traditional NPs. The current review article discussed nanomaterial performance, including carbon nanotubes (CNTs), graphene, MXene and polymers-based biomedical applications. The current state of nanomaterials in the biomedical area is illustrated in this summary article, along with applications and the significance of characterization approaches. The advanced methods for examining the interior geometry, structure, and morphology of nanomaterials are discussed in this piece of writing, including Transmission electron microscopy (TEM), Scanning electronic microscopy (SEM), Atomic Force Microscopy (AFM), Magnetic resonance force microscopy (MRFM) and X-ray diffraction (XRD). Finally, the authors discussed the issues associated with nanomaterials in biomedical applications.

Aim

To evaluate the in vivo toxicity of the anionic nanoliposome formulation containing [hydrogenated soy phosphatidylcholine (HSPC)] and [1,2-distearoyl-sn-glycero-3- phosphoglycerol (DSPG)].

Methods

The anionic nanoliposome formulation was prepared by the lipid film hydration method. To assess the toxicity of anionic nanoliposomes, male and female albino mice were weakly treated with intravenous injection of the formulation (100 μmol/kg) for four weeks. The toxicity study was performed by the subacute protocol, four weeks after the last injection. To this end, the plasma levels of lipid indexes, urea, creatinine, AST, ALT, ALP, and fasting blood glucose (FBG) were measured. To evaluate histopathological alterations, the tissues of the vital organs including the heart, liver, kidneys, spleen, and brain were studied using hematoxylin & eosin (H&E) staining.

Results

The results showed nonsignificant changes in total cholesterol, LDL-C, HDL-C, creatinine, urea, AST, ALP, and ALT in the liposome-treated mice when compared with control mice. However, plasma levels of triglycerides were significantly decreased (by 64.5 ± 15.3 mg/dL, p = 0.001) and (by 58.75 ± 15.3 mg/dL, p = 0.002) in the liposome-treated male and female mice, respectively, when compared with corresponding control mice. The FBG level was significantly increased by154 ± 20 mg/dL, p = 0.001 in the liposome-treated male mice when compared with the control male mice. The PAB level was significantly decreased by 12 ± 4.2 HK, p = 0.03 in the liposome-treated male mice when compared with the control male mice. Histological examination of vital organs indicated no significant differences in tissue damage between the liposome-treated and control mice.

Conclusion

The findings of the present study indicated that DSPG-containing nanoliposome formulation exerted no significant adverse effects on the function of vital organs and blood levels of biochemical biomarkers in healthy mice. However, further investigations are needed to find a safe dose of DSPG liposomes concerning the risk of diabetes.