Recent Patents on Materials Science - Volume 11, Issue 1, 2018

A major drawback of some polymers is their low impact resistance and ability to absorb energy during fracture, such as PS, PMMA and PVC. Several techniques are used to toughen or modify impact resistance of brittle polymers, including reinforcement such as fibers and particles, or the incorporation of an elastomeric second phase. Whilst synthetic polymers can provide desirable properties for a wide variety of applications, there is a large environmental impact associated to those produced through petrochemical routes. Hence, in recent decades, much emphasis has been placed on polymer systems from renewable resources, as well as those able to undergo biodegradation due to enzymes and microbes. Blending of biopolymers is an area of high interest due to the promise shown in these materials and the potential for the replacement of petrochemical-based polymers, although the ability of these materials to absorb high levels of energy during fracture, whilst maintaining other acceptable mechanical properties, remains an issue. This paper presents a review of various patents about polymer, morphology development and impact strength modification, linking these topics to the formation of toughened biopolymer materials and blends.

Background: The synthesis of one-dimensional Cu nanomaterials, e.g. nanowires or nanorods, normally invovles the use of hard templates, organic additives, or some special conditions, e.g. high vacuum or electric field as discussed in patents. Objective: Herein, we report that, in the absence of any hard template and organic additives, Cu nanorods can be spontaneously formed during low-temperature reduction of Cu2O cubes. Method: The conversion of Cu2O cubes into Cu nanrods is conducted in an alkaline KHB4 aqueous solution at a temperature of 30°C. Results: Nanoparticle-like Cu can be observed on the surface of the cubes in the early stage of reduction. As the reduction reaction proceeds, rod-like Cu appears and some of the cubes can be totally destroyed by the growth of Cu nanorods. Detailed examination of these Cu nanorods reveals that some nanorods are obviously composed of nanoparticles. Moreover, the spontaneous formation of Cu nanorods can be hindered by the addition of ethylenediamine, where Cu cubes made up of Cu nanoparticles can be obtained. Conclusion: Based on these experimental results, a mechanism based on nanoparticle oriented attachment was proposed for the growth of Cu nanorods by liquid-phase reduction of Cu2O cubes.

Background: While most of the prominent features in the Raman spectrum of graphene are well understood as mentioned in patents within the Double Resonance (DR) picture, the origin of the peak at 2450 cm-1 (also called the G* band) still remains unclear. Method and Objective: In this work, we performed detailed Raman studies of single- and few-layer graphene using multiple laser excitations to unravel the origin of G* band. Results: Based on our analyses, we conclude that the G* band arises from a combination of Transverse Optical (iTO) and Longitudinal Acoustic (LA) phonons, and exhibits an asymmetric peak structure due to the presence of two different time-order phonon processes. The lower (higher) frequency sub-peak is ascribed to an LA-first (iTO-first) process. We provide three strong experimental evidences for the time-ordered scattering processes: the dependence of the G* band sub-peaks with (i) increasing laser energy, (ii) increasing defects, and (iii) increasing temperature. Finally, we attribute the enhanced asymmetry of the G* band in multi-layer graphene to multiple processes between electronic sub-bands, similar to the G' band in multi-layer graphene. Conclusion: Our study uncovered the origin and nature of the G* peak in the Raman spectrum of graphene. We believe our results have important implications for processes such as graphene-enhanced Raman scattering, where the time-ordered scattering of optical and acoustic phonons can be very useful for sensing analytes.

Background: Degradable polymeric particles derived from phenolic compounds are promising materials for biomedical applications due to their inherently antioxidant, antimicrobial, and anticancerogenic properties. We revise all the patent regarding to the biomedical and food additive formulations of Rutin (RT) and Quercetin (QC) as phenolic compounds. Objective: Prepare degradable Poly(Rutin) (p(RT)) and Poly(Quercetin) (p(QC)) particles from natural phenolic compounds, Rutin (RT) and Quercetin (QC). Method: P(RT), and p(QC) particles were prepared using microemulsion crosslinking method employing phenolic compounds such as RT and QC as monomer and poly(ethylene glycol) diglycidyl ether (PEGGE) as a crosslinker in a single step. The degradability of these particles was investigated at physiological conditions, pH 5.4, 7.4, and 9 at 37.5°C. The antioxidant capacity of RT, QC and their corresponding particles was determined by means of total phenol content and ABTS+ scavenging assay. The blood compatibility of the particles is determined with hemolysis and blood clotting tests, and the cytotoxicity of the particles on L929 fibroblast cell and A549 cancer cells was done by WST-1 tests. Results: The size of the prepared phenolic particles was in the size range of 0.4 - 4 μm with negative zeta potentials, -20.29±1.7 and -31.31±2.0 mV for p(RT) and p(QC) particles, respectively. The highest amount of degradation was obtained for p(QC) particles in almost a linear profile with relatively longer time degrading kinetics at pH 9, e.g., 197±23 mg/g QC was released up to 130 h. The antioxidant capacities of phenolic compounds were decreased about ten-fold upon the particle formations of the phenolic compound, and the antioxidant capacity of p(QC) particles was found to be better than p(RT) particles with 0.22±0.01 and 0.05±0.001 μmol trolox equivalent g-1, respectively. The blood compatibility test of p(RT) and p(QC) particles revealed that both particles are blood compatible up to 1 mg/mL concentration and possess clotting of blood over 1 mg/mL concentrations. Furthermore, the cytotoxicity tests showed that p(RT) particles are more biocompatible than p(QC) on the fibroblast cell as 91% cell viability versus 50% for p(QC) was observed at 75 μg/mL particle concentrations. Additionally, at this concentration 42.3% of cancer cells were inhibited by p(RT) particles. Conclusion: Degradable p(RT) and p(QC) particles that are prepared in a single step offer great avenue for biomedical applications as highly antioxidant materials and with good biocompatibility in contact with blood and fibroblast cells, as well as great anticancerogenic capability against the cancer cells.

Background: PbSe is A4B6 group narrow gap material with energy gap about 0.3 eV. InSe is A3B6 group with energy gap 1.3 eV and layered structure. In the layers, covalent bonds are present, while Van Der Waals force acts between layers. When Pb ratio is high and the In ratio is low we have PbSe, but with nanostructure in present work. Hence better electrical properties are expected. In the case of higher indium ratio and lower Pb ratio, we obtain really a mixture of PbSe and InSe, with expected lower conductivity. Authors revised all patents relating to the effect of In addition to PbSe thin films. Objective: The aim of the present work is to study the effect of In substitution on the structural, electrical and optical properties of PbSe nanocrystalline films. Method: The bulk compositions Pb55.03In6.58Se38.39 and Pb32.54In29.55Se38.01 were prepared by solid solution reaction and their thin films were deposited by thermal evaporation technique. The structural and morphological analyses were carried out by X-Ray Diffraction, scanning electron microscope, and high resolution transmission electron microscope. The optical properties were studied by using spectrophotometer measurements. The galvanomagnetic properties were studied by means of conductivity, Hall Effect and magnetoresistance. Results and Conclusion: XRD of Pb32.54In29.55Se38.01 and Pb55.03In6.58Se38.39 films showed polycrystalline cubic structure. The optical band gap for Pb55.03In6.58Se38.39 and Pb32.54In29.55Se38.01 films is determined as 1.77 and 1.67 eV, respectively. Electrical conductivity, charge carriers concentration, mobility and magnetoresistance of Pb32.54In29.55Se38.01 and Pb55.03In6.58Se38.39films were investigated as a function of temperature. The films with the higher Pb content demonstrated higher crystallinity, conductivity, mobility, and magnetoresistance.

Background: Spinel ferrites are compound oxides with a general chemical formula of AB2O4, where A and B are divalent and trivalent ions, respectively. They can be a transparent conductor or ferromagnetic insulator and show many outstanding properties that are applicable in high technological devices, such as microwave absorbers, photocatalytic activities, lithium-ion battery, spintronics and so forth. Their magnetic properties are sensitive to fabrication and processing conditions, particularly for nanostructured spinel ferrites due to the redistribution of Fe ions at A and B sites as discussed in relevant patents. Objective: We have prepared Zn0.5Co0.5Fe2O4 nanoparticles (ZCFO NPs) and studied in detail the influence of the annealing temperature (Tan) and ambience on their structural and magnetic properties at room temperature. Method: ZCFO NPs prepared by a hydrothermal method were annealed at temperatures Tan = 393-1573 K in air and Ar gas for 4 h at atmospheric pressure. The surface morphology and chemical composition of NPs were analyzed by using a field-emission scanning electron microscope equipped with energy dispersive X-ray spectroscopy. The crystal structure was checked by an X-ray diffractometer. Vibration spectra were acquired with a micro-Raman spectrometer. The magnetic properties at RT were studied by using a vibrating sample magnetometer. Results: Careful analyses of X-ray diffraction patterns and Raman spectra indicate that the samples with Tan < 873 K are single phase and stable in the cubic-spinel structure. The annealing at higher temperatures, Tan ≥ 873 K, leads to the formation of a secondary phase (α-Fe2O3, hematite). This reduces rapidly the saturation magnetization (Ms) of ZCFO NPs. Particularly, around Tan = 1473 K, we have found a partial recovery of cubic-spinel NPs, making Ms slightly increased. The recovery ability in the Ar ambience is better than that in air. Conclusion: Results showed that ZCFO NPs prepared by a hydrothermal method were unstable versus heat treatment. While the cubic-spinel structure remains unchanged at Tan < 873 K, the annealing at temperatures Tan ≥ 873 K leads to the formation of α-Fe2O3, and around Tan = 1473 K, there was a partial recovery of the cubic spinel phase. Notably, the co-presence of Co and Zn in ZCFO NPs restricts remarkably the recovery ability of the spinel structure. Such structural changes influence directly the exchange interactions between Fe ions at the A and B sites of the spinel structure, leading to the variations of Ms and Hc versus Tan and annealing ambience.