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Topic Review
Vitreous Substitute
The ideal vitreous substitute should mimic the native vitreous in terms of both structure and function such as transparency, biocom-patibility, elasticity, easy injectability, except for its liquefication and biodegradability with age. Current vitreous substitutes are used in order to maintain certain criterias such as optical and biomechanical properties and intraocular pressure. Therefore, extensive research with biomaterials is underway taking into consideration its composition, structure and physiological properties as well to overcome the downside of the currently used tamponades.
  • 804
  • 15 Jan 2021
Topic Review
Methods for Reducing Water Absorption of Composite Materials
Plant fiber reinforced polymer matrix composites have attracted much attention in many industries due to their abundant resources, low cost, biodegradability, and lightweight properties. Compared with synthetic fibers, various plant fibers are easy to obtain and have different characteristics, making them a substitute for synthetic fiber composite materials. In order to address the adverse effects of natural fiber moisture absorption on the mechanical properties and dimensional stability of composite materials, researchers have modified fibers through various chemical and physical methods. The various methods to reduce the water absorption of composite materials such as fiber surface chemical treatment, the use of compatibilizers, fiber mixing, nanofillers, and polymer coatings.
  • 803
  • 27 Oct 2023
Topic Review
Polymer Electrolyte Membranes Fuel Cell
The development of sulfonated hydrocarbon polymer (SHP)-based polymer electrolyte membranes (PEMs) has been pursued in order to overcome drawbacks of the perfluorosulfonic acid ionomer-based PEMs in fuel cell applications. To improve the proton conductivity of SHP-based PEMs without deterioration in physicochemical stability, control of polymeric architecture is necessary to form distinct phase-separated structures between the hydrophilic and hydrophobic domains. By pursuing rational design strategies for the copolymer architectures, it will be possible to develop high-performance SHP-based PEMs in fuel cell applications. This study focused on the synthetic procedures which underlie structure-engineered copolymers and their PEM properties.
  • 801
  • 22 Oct 2021
Topic Review
Supramolecular Polymer Nanocomposites
Polymer nanocomposites, a class of innovative materials formed by polymer matrixes and nanoscaled fillers (e.g., carbon-based nanomaterials, inorganic/semiconductor nanoparticles, metal/metal-oxide nanoparticles, polymeric nanostructures, etc.), display enhanced mechanical, optoelectrical, magnetic, catalytic, and bio-related characteristics, thereby finding a wide range of applications in the biomedical field. In particular, the concept of supramolecular chemistry has been introduced into polymer nanocomposites, which creates myriad “smart” biomedical materials with unique physicochemical properties and dynamic tunable structures in response to diverse external stimuli. 
  • 794
  • 25 Feb 2021
Topic Review
3D Printed Silicone Meniscus Implants
Osteoarthritis of the knee with meniscal pathologies is a severe meniscal pathology suffered by the aging population worldwide. However, conventional meniscal substitutes are not 3D-printable and lack the customizability of 3D printed implants and are not mechanically robust enough for human implantation. Similarly, 3D printed hydrogel scaffolds suffer from drawbacks of being mechanically weak and as a result patients are unable to execute immediate post-surgical weight-bearing ambulation and rehabilitation. To solve this problem, we have developed a 3D silicone meniscus implant which is (1) cytocompatible, (2) resistant to cyclic loading and mechanically similar to native meniscus, and (3) directly 3D printable. The main focus of this study is to determine whether the purity, composition, structure, dimensions and mechanical properties of silicone implants are affected by the use of a custom-made in-house 3D-printer. We have used the phosphate buffer saline (PBS) absorption test, Fourier transform infrared (FTIR) spectroscopy, surface profilometry, thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) to effectively assess and compare material properties between molded and 3D printed silicone samples.
  • 794
  • 17 Apr 2021
Topic Review
Lignin as Renewable Building Block for Sustainable Polyurethanes
Lignin, being a natural aromatic polymer rich in functional hydroxyl groups, has been drawing the interest of academia and industry for its valorization, especially for the development of polymeric materials. Among the different types of polymers that can be derived from lignin, polyurethanes (PUs) are amid the most important ones, especially due to their wide range of applications. Lignin, being a natural aromatic polymer rich in functional hydroxyl groups, has been drawing the interest of academia and industry for its valorization, especially for the development of polymeric materials. Among the different types of polymers that can be derived from lignin, polyurethanes (PUs) are amid the most important ones, especially due to their wide range of applications. 
  • 793
  • 20 Oct 2022
Topic Review
High-Voltage Film Capacitors
High-voltage capacitors are key components for circuit breakers and monitoring and protection devices, and are important elements used to improve the efficiency and reliability of the grid. Different technologies are used in high-voltage capacitor manufacturing process, and at all stages of this process polymeric films must be used, along with an encapsulating material, which can be either liquid, solid or gaseous.
  • 791
  • 24 Mar 2021
Topic Review
Synthesis of Ferrocenyl Phosphorhydrazone Dendrimers
The discovery of ferrocene is often associated with the rapid growth of organometallic chemistry. Dendrimers are highly branched macromolecules that can be functionalized at will at all levels of their structure. The functionalization of dendrimers with ferrocene derivatives can be carried out easily as terminal functions on the surface, but also at the core, or at one or several layers inside the structure. Depending on the desired location of the ferrocenes in the structure of phosphorhydrazone dendrimers, the ferrocenes should be functionalized differently. For the grafting to the surface, the ferrocene should bear a phenol group, suitable to react in substitution reactions with the P(S)Cl2 terminal groups of the dendrimers. To be used as core, the ferrocene should have two aldehyde functions, from which the synthesis of the dendrimer will be carried out. To be introduced in the branches, at all layers or within a single layer, the ferrocene should replace hydroxybenzaldehyde; thus, it should bear both a phenol and an aldehyde.
  • 788
  • 06 Jun 2022
Topic Review
Aggregation-Induced Emission Properties in Polymers
Aggregation-Induced Emission (AIE) is a phenomenon that consists of the appearance of fluorescence in solid state or aggregation greater than that of molecules in solution and has recently attracted the attention of the scientific community because of their potential applications in different fields. Compared to small molecules, little attention has been paid to polymers and oligomers that exhibit AIE, despite having excellent properties such as high emission efficiency in aggregate and solid states, signal amplification effect, good processability and the availability of multiple functionalization sites. In addition to these features, if the molecular structure is fully conjugated, intramolecular electronic interactions between the composing chromophores may appear, thus giving rise to a wealth of new photophysical properties. In this review, we focus on selected fully conjugated oligomers, dendrimers and polymers, and briefly summarize their synthetic routes, fluorescence properties and potential applications. An exhaustive comparison between spectroscopic results in solution and aggregates or in solid state has been collected in almost all examples, and an opinion on the future direction of the field is briefly stated.
  • 784
  • 02 Feb 2021
Topic Review
Synthetic Polymer-Based Sensors
Polymers are long-chain, highly molecular weight molecules containing large numbers of repeating units within their backbone derived from the product of polymerization of monomeric units. The materials exhibit unique properties based on the types of bonds that exist within their structures. Among these, some behave as rubbers because of their excellent bending ability, lightweight nature, and shape memory. Moreover, their tunable chemical, structural, and electrical properties make them promising candidates for their use as sensing materials. Polymer-based sensors are highly utilized in the current scenario in the public health sector and environment control due to their rapid detection, small size, high sensitivity, and suitability in atmospheric conditions.
  • 781
  • 16 Jun 2022
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