International Journal of Polymer Analysis and Characterization最新文献

In recent years, the development of portable electronic devices has increased considerably. Polymers and polymer composites are employed in a variety of industries, from structural materials to electronics, as well as in our daily lives. PLA@LiYO₂ nanocomposites films were subsequently fabricated by a simple solution casting at various concentrations for the development of electronic materials. The effective doping and homogeneous dispersion of nanoparticles in PLA polymer is characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), Fourier Transform InfraRed (FTIR) spectrophotometer, Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), elastic and dielectric properties of PLA composites films. XRD analysis showed that the crystalline characteristics of the nanocomposites increases with increase in dopant concentration. The FTIR absorption spectra of neat PLA and PLA@LiYO₂ nanocomposites are almost equivalent to each other, from TGA analysis there will be less percentage of weight loss in the composite’s films as the concentration of the nanocomposites increased into PLA matrix, Moreover, a significant increase in Tg with an increase in NPs content from 0 to 4 wt% was also observed, the different elastic moduli such as E, K and G of PLA + LiYO₂ films are indirectly proportional to the addition of LiYO₂ in to PLA matrix. The doped PLA nanocomposites exhibit unique negative dielectric constant and AC conductivity.

In the present research work phosphorus-based moiety, phosphorus-based epoxy resin and its acrylated vinyl ester resin were synthesized. These compounds were characterized by chemical and instrumental methods. Styrene was added into vinyl ester resin in different proportions and different systems were prepared. These systems were blended with commercial epoxy resin (DGEBA) and by varying the ratios different blends were prepared. These blends were cast into the molds and coated on mild steel panels. Mechanical, thermal and flame-retardant properties of films were found as per standard methods. Mechanical properties and chemical resistance properties of coated panels were also found.

Although several properties of collagen have been explored, the blend formation with sulfated polymers is poorly explored. Antiplatelet effects can be achieved after the formation of this type of blend. In this work, a film formed by collagen and sulfated polysaccharide and their properties were analyzed. Five blends were produced, blend with collagen (10 mg/g) and 0, 5, 10, 20, and 25% of the sulfated polysaccharide. No changes amine (I, II, and III) vibrations alterations were observed, where the collagen structure remained unchanged. In addition, it was also observed the presence of sulfoxide groups related to the presence of sulfated polysaccharides. The samples have the same thermal degradation profile. Additionally, the stability of the film is up to 100 °C, characterized by the loss of water from the structure caused by the break-up of the blend. Also, it was verified that the adhesion of platelets to the collagen decreases with the presence of sulfated polysaccharide. The synthesized material presents a potential for application as an anti-thrombogenic agent, besides being biodegradable and biocompatible.

Recently, there has been a growing interest in novel technologies dealing with environmental aspects that leads us to effective utilization of the available natural resources and better waste management strategies. The last few decades have witnessed the application of several natural fibers in composite industries ensuing relatively high strength polymer composites, which are promising eco-friendly alternative to man-made synthetic composites. Especially, Date Palm fibers (DPF) are of specific interest, as they possess desirable properties such as light weight and low density, superior mechanical strength and thermal conductivity, and are considered as very good substitutes for synthetic composites. There are several earlier research on DPF as fillers for polymer reinforcement. However, there is an insufficient comprehensive and comparative study of various DPF reinforced polymer composites, which will assist the scientists to expand their knowledge on the fabrication of surface modified DPF for effective polymer reinforcements. This review provides a summary of the surface microstructure, highly polar chemical nature of fiber, required surface modifications that will enhance the interfacial bonding of fiber to the polymer matrix and a critical in-depth analysis of the different types of DPF composites and their physico-mechanical and thermal properties.

Hydrogels are 3 D cross-linked networking of polymeric materials having the capacity to absorb a tremendous amount of water within the network. Many techniques have been introduced for the characterization of synthesized gels. Most common are the spectroscopic methods (UV/Vis, FTIR) used at the molecular and atomic level, diffraction method (XRD) used for measurement of crystallinity within the structure, microscopy (SEM, TEM) to know about the surface texture and morphology and rheology for the elucidation of viscoelastic behavior of hydrogels. Many industries especially pharmaceutical, cosmetic, food processing, agriculture, water treatment, and other related research fields are directly dependent on the rheological characterization of hydrogels for their possible and related application. Similarly, the final design of the product also depends on characterization at a microscopic level to understand the structure and type of interaction within the hydrogel network and its behavior toward the applied external forces. In the present review paper, we have focused on and tried to grip the rheology of synthetic, natural, and semi synthetics hydrogels-based materials and their application in daily life on an industrial scale.

Carbonized Polymer Nanomaterials (CPNs) have acquired substantial research interest in recent years due to their budding applications in various optical and electrochemical studies like electrocatalysis, solar cells, biosensing, etc. Due to their stability and toxicity, the enhancement of CPNs' properties was the primary cause of concern. Herein, we synthesized Nitrogen-doped (N-doped) N-CPNs using the one-step hydrothermal approach of PVA and PVDF polymers with Nitric acid (HNO₃) as the nitrogen source. The luminescence intensity was observed to be enhanced by increasing nitrogen doping concentration. The synthesized fluorescent samples exhibited significant antibacterial properties, making them useful in biomarkers, sensing strategies, drug delivery, etc. Doped PVA samples exhibited negligible antibacterial activity, but nitrogen-doped PVDF samples displayed considerable biocidal activity against gram-positive bacteria, according to antibacterial research. Each sample's growth inhibition was distinct and species-specific.

For the first time, poly(N-isopropylacrylamide) (PNIPAAm) star polymers with a β-cyclodextrin core are characterized in detail by size-exclusion chromatography (SEC) with triple detection to experimentally verify the number of arms. A combination of a refractive index detector, multi-angle laser light scattering detector, and an online-viscosimeter was used for branching analysis. At first, the SEC system was calibrated and the detector setup was validated using linear polystyrene reference polymers. The applicability of the established triple detection SEC for branching analysis was shown by the analysis of two commercially available polystyrene star polymers. Due to the high molar masses of the star polymers, both the contraction ratio g and g′ could be determined independently, thus allowing the calculation of the viscosity shielding ratio ε. Finally, the branching analysis of the PNIPAAm star polymers could experimentally confirm the assumed arm number of up to 21 arms. Moreover, an increasingly compact molecular structure and the influence of the arm number on the viscosity shielding ratio could be shown.

Flexible dielectric materials are widely explored and used for energy storage applications. In this paper, we present a research work on the development of new flexible dielectric films by combining poly(vinyl alcohol) (PVA) used as flexible polymer matrix and reduced grapheme oxide (rGO) and barium titanate (BaT) added in different ratios to tailor their capacitance. The properties of resultant nanocomposite films have been tailored based on the properties of their constituents; flexibility of the PVA, high thermal stability better dielectric properties due to both fillers i.e., rGO and BaT. The synthesized nanocomposite films prepared by different ratio of these three components were characterized for their structural, chemical, morphological, thermal, and dielectric properties. Their dielectric studies carried using impedance analyzer at room temperature revealed that nanocomposite with rGO:barium titanate:poly(vinyl alcohol) = 0.3:2.5:10 shows excellent real part of permittivity of 66 at 20 Hz which decreased to 10.9 at very high frequency of 2 MHz and low energy loss of 0.8 at 20 Hz which was reduced to 0.06 at 2 MHz. Also energy storage capacity of nanocomposites was calculated, and it was found that rGO:barium titanate:poly(vinyl alcohol) = 0.3:1:10 showed best energy storing properties with total energy density, recoverable energy density, and energy loss of 2.1 × 10⁻⁴ kJ/m³, 1.5 × 10⁻⁴ kJ/m³, and 5.2 × 10⁻⁵ kJ/m³. Its efficiency was 71%. The presented synthesized flexible dielectric films with tailorable dielectric performances are very desirable for flexible capacitor sensing application due to their excellent flexibility, efficient thermal, and dielectric properties.