Block-assembling: a new strategy for fabricating conductive nanoporous materials from nanocomposites based on a melt-miscible crystalline/crystalline blend and MWCNTs

2015 ◽  
Vol 3 (33) ◽  
pp. 8510-8518 ◽  
Author(s):  
Lijun Ye ◽  
Cuicui Ye ◽  
Xianchun Shi ◽  
Hongyan Zhao ◽  
Kangyuan Xie ◽  
...  
Keyword(s):  
Polymeric Materials ◽  
Nanoporous Materials ◽  
New Strategy

A “block-assembling” strategy is explored to fabricate conductive nanoporous polymeric materials with a unique interposition structure of CNTs in the inner wall of the internal pores.

Synthesis and characterization of polyvinylmethylsiloxanes by cationic polymerization using a solid green catalyst

e-Polymers ◽  
2017 ◽  
Vol 17 (5) ◽  
pp. 439-448 ◽  
Author(s):  
Djamal Eddine Kherroub ◽  
Mohammed Belbachir ◽  
Saad Lamouri
Keyword(s):  
Ring Opening ◽  
Polymeric Materials ◽  
Synthesis And Characterization ◽  
Green Catalyst ◽  
Characterization Methods ◽  
H Nmr ◽  
New Strategy ◽  
Cationic Ring Opening Polymerization ◽  
C Nmr

AbstractThe present work is devoted to the synthesis and characterization of vinylsiloxane polymers produced by the use of an activated natural catalyst known as Maghnite-H+. The cationic ring opening polymerization of pentavinylpentamethylcyclopentasiloxane (V5D5) made it possible to obtain the desired polymeric materials. Through this study, we have adapted a new strategy of synthesis of a siloxane polymer with relatively high molecular mass, using a solid initiator activated by sulfuric acid, which has enabled us to combine the ecological aspect of synthesis and the effectiveness of the catalyst in this kind of reaction. Structural [infrared (IR), proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR)], thermal differential scanning (DSC) and chromatographic (GPC) characterization methods have allowed the products obtained to be identified and their various properties to be focused on. The kinetic study was made to determine the order of the reaction. The proposed reaction mechanism shows the advantages of Maghnite-H+.

scholarly journals Polymeric nanoporous materials fabricated with supercritical CO2 and CO2-expanded liquids

2014 ◽  
Vol 43 (20) ◽  
pp. 6938-6953 ◽  
Author(s):  
Aijuan Zhang ◽  
Qingkun Zhang ◽  
Hua Bai ◽  
Lei Li ◽  
Jun Li
Keyword(s):  
Supercritical Co2 ◽  
Recent Progress ◽  
Polymeric Materials ◽  
Nanoporous Materials

This tutorial review focuses on the recent progress in nanoporous polymeric materials fabricated by newly developed supercritical techniques.

scholarly journals Stimulus-responsive liquids for encapsulation storage and controlled release of drugs from nano-shell capsules

2010 ◽  
Vol 8 (56) ◽  
pp. 451-456 ◽  
Author(s):  
Ming-Wei Chang ◽  
Eleanor Stride ◽  
Mohan Edirisinghe
Keyword(s):  
Drug Delivery ◽  
Controlled Release ◽  
Drug Release ◽  
Polymeric Materials ◽  
Controlled Drug Release ◽  
Ambient Conditions ◽  
Smart Polymer ◽  
Release Studies ◽  
Stimulus Responsive ◽  
New Strategy

Drug-delivery systems with a unique capability to respond to a given stimulus can improve therapeutic efficacy. However, development of such systems is currently heavily reliant on responsive polymeric materials and pursuing this singular strategy limits the potential for clinical translation. In this report, with a model system used for drug-release studies, we demonstrate a new strategy: how a temperature-responsive non-toxic, volatile liquid can be encapsulated and stored under ambient conditions and subsequently programmed for controlled drug release without relying on a smart polymer. When the stimulus temperature is reached, controlled encapsulation of different amounts of dye in the capsules is achieved and facilitates subsequent sustained release. With different ratios of the liquid (perfluorohexane): dye in the capsules, enhanced controlled release with real-time response is provided. Hence, our findings offer great potential for drug-delivery applications and provide new generic insights into the development of stimuli drug-release systems.

scholarly journals Photochemistry Meets Porous Organic Cages

2021 ◽  
Vol 75 (4) ◽  
pp. 285-290
Author(s):  
Hsin-Hua Huang ◽  
Tomáš Šolomek
Keyword(s):  
Organic Solvents ◽  
Photophysical Properties ◽  
Metal Organic Frameworks ◽  
Polymeric Materials ◽  
Nanoporous Materials ◽  
The Past ◽  
Metal Organic ◽  
The Rich ◽  
As Solubility ◽  
Molecular Nature

Chemistry of porous organic cages has developed in the past decade as an alternative to the wellknown nanoporous materials based on extended networks, such as metal organic frameworks (MOFs) or covalent organic frameworks (COFs). Unlike these extended polymeric materials, the molecular nature of organic cages offers important advantages, such as solubility of the material in common organic solvents. However, a simultaneous combination of porosity and additional optoelectronic properties, common in MOFs and COFs, is still quite rare. Therefore, porous organic cages are relatively underdeveloped when compared to MOFs and COFs. Here, we highlight the rich possibilities the porous organic cages offer and discuss the recent development where interesting photophysical properties augment the porosity, including our own work.

scholarly journals 3D-Printed Polyester-Based Prototypes for Cosmetic Applications—Future Directions at the Forensic Engineering of Advanced Polymeric Materials

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 994 ◽  
Author(s):  
Joanna Rydz ◽  
Wanda Sikorska ◽  
Marta Musioł ◽  
Henryk Janeczek ◽  
Jakub Włodarczyk ◽  
...  
Keyword(s):  
Material Properties ◽  
Three Dimensional ◽  
Accelerated Aging ◽  
Polymeric Materials ◽  
Gel Permeation Chromatography ◽  
Operating Conditions ◽  
Test Procedures ◽  
Scanning Calorimetry ◽  
New Strategy ◽  
Forensic Engineering

Knowledge of degradation and impairment phenomena of (bio)degradable polymeric materials under operating conditions, and thus the selection of test procedures and prediction of their behavior designates the scope and capabilities as well as possible limitations of both: the preparation of the final product and its durability. The main novelty and objective of this research was to determine the degradation pathways during testing of polylactide and polylactide/polyhydroxyalkanoate materials made with three-dimensional printing and the development of a new strategy for the comprehensive characterization of such complex systems including behavior during waste disposal. Prototype objects were subjected to tests for damage evolution performed under simulating operating conditions. The reference samples and the tested items were characterized by gel permeation chromatography and differential scanning calorimetry to determine changes in material properties. The studies showed that: polyhydroxyalkanoate component during accelerated aging and degradation in environments rich in microorganisms accelerated the degradation of the material; paraffin accelerates polylactide degradation and slows degradation of polyhydroxyalkanoate-based material; under the influence of an environment rich in enzymes, paraffin contamination accelerates biodegradation; under the influence of natural conditions, paraffin contamination slowed degradation; the processing conditions, in particular the printing orientation of individual parts of the container, influenced the material properties in its various regions, affecting the rate of degradation of individual parts.

scholarly journals Recent Progress in Hybrid Biocomposites: Mechanical Properties, Water Absorption, and Flame Retardancy

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5145
Author(s):  
Mohsen Bahrami ◽  
Juana Abenojar ◽  
Miguel Ángel Martínez
Keyword(s):  
Fossil Fuel ◽  
Low Cost ◽  
Natural Fibers ◽  
Polymeric Materials ◽  
Strength Properties ◽  
Limited Resources ◽  
Environmental Concerns ◽  
Mechanical And Physical Properties ◽  
New Strategy ◽  
The Matrix

Bio-based composites are reinforced polymeric materials in which one of the matrix and reinforcement components or both are from bio-based origins. The biocomposite industry has recently drawn great attention for diverse applications, from household articles to automobiles. This is owing to their low cost, biodegradability, being lightweight, availability, and environmental concerns over synthetic and nonrenewable materials derived from limited resources like fossil fuel. The focus has slowly shifted from traditional biocomposite systems, including thermoplastic polymers reinforced with natural fibers, to more advanced systems called hybrid biocomposites. Hybridization of bio-based fibers/matrices and synthetic ones offers a new strategy to overcome the shortcomings of purely natural fibers or matrices. By incorporating two or more reinforcement types into a single composite, it is possible to not only maintain the advantages of both types but also alleviate some disadvantages of one type of reinforcement by another one. This approach leads to improvement of the mechanical and physical properties of biocomposites for extensive applications. The present review article intends to provide a general overview of selecting the materials to manufacture hybrid biocomposite systems with improved strength properties, water, and burning resistance in recent years.

The Resolution and Contrast in Biological Sections Determined by Inelastic and Elastic Scattering

1973 ◽  
Vol 31 ◽  
pp. 224-225
Author(s):  
D. L. Misell
Keyword(s):  
Electron Microscopy ◽  
Adverse Effect ◽  
Elastic Scattering ◽  
Inelastic Scattering ◽  
Amorphous Carbon ◽  
Polymeric Materials ◽  
Chromatic Aberration ◽  
Image Resolution ◽  
Quantitative Estimates ◽  
Elastic Ratio

In the electron microscopy of biological sections the adverse effect of chromatic aberration on image resolution is well known. In this paper calculations are presented for the inelastic and elastic image intensities using a wave-optical formulation. Quantitative estimates of the deterioration in image resolution as a result of chromatic aberration are presented as an alternative to geometric calculations. The predominance of inelastic scattering in the unstained biological and polymeric materials is shown by the inelastic to elastic ratio, I/E, within an objective aperture of 0.005 rad for amorphous carbon of a thickness, t=50nm, typical of biological sections; E=200keV, I/E=16.

Application Of Electron Microscopy To Automotive Finish Defect Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 258-259
Author(s):  
Martin J. Mahon ◽  
Patrick W. Keating ◽  
John T. McLaughlin
Keyword(s):  
Electron Microscopy ◽  
Zero Tolerance ◽  
Polymeric Materials ◽  
Plant Management ◽  
Defect Analysis ◽  
X Ray ◽  
Root Cause ◽  
Cutting Out ◽  
Foreign Materials ◽  
Automotive Finish

Coatings are applied to appliances, instruments and automobiles for a variety of reasons including corrosion protection and enhancement of market value. Automobile finishes are a highly complex blend of polymeric materials which have a definite impact on the eventual ability of a car to sell. Consumers report that the gloss of the finish is one of the major items they look for in an automobile.With the finish being such an important part of the automobile, there is a zero tolerance for paint defects by auto assembly plant management. Owing to the increased complexity of the paint matrix and its inability to be “forgiving” when foreign materials are introduced into a newly applied finish, the analysis of paint defects has taken on unparalleled importance. Scanning electron microscopy with its attendant x-ray analysis capability is the premier method of examining defects and attempting to identify their root cause.Defects are normally examined by cutting out a coupon sized portion of the autobody and viewing in an SEM at various angles.

Colloidal systems in soils

1994 ◽  
Vol 52 ◽  
pp. 64-65
Author(s):  
J. Thieme ◽  
J. Niemeyer ◽  
P. Guttman
Keyword(s):  
Clay Minerals ◽  
Polymeric Materials ◽  
Spatial Arrangement ◽  
High Specific Surface Area ◽  
Turnover Rates ◽  
Colloidal Systems ◽  
Chemical Conditions ◽  
Aggregation Phenomena ◽  
Iron And Manganese ◽  
Soil Colloids

In soil science the fraction of colloids in soils is understood as particles with diameters smaller than 2μm. Clay minerals, aquoxides of iron and manganese, humic substances, and other polymeric materials are found in this fraction. The spatial arrangement (microstructure) is controlled by the substantial structure of the colloids, by the chemical composition of the soil solution, and by thesoil biota. This microstructure determines among other things the diffusive mass flow within the soils and as a result the availability of substances for chemical and microbiological reactions. The turnover of nutrients, the adsorption of toxicants and the weathering of soil clay minerals are examples of these surface mediated reactions. Due to their high specific surface area, the soil colloids are the most reactive species in this respect. Under the chemical conditions in soils, these minerals are associated in larger aggregates. The accessibility of reactive sites for these reactions on the surface of the colloids is reduced by this aggregation. To determine the turnover rates of chemicals within these aggregates it is highly desirable to visualize directly these aggregation phenomena.

Pyridyl disulfide-based thiol–disulfide exchange reaction: shaping the design of redox-responsive polymeric materials

2020 ◽  
Vol 11 (48) ◽  
pp. 7603-7624
Author(s):  
Ismail Altinbasak ◽  
Mehmet Arslan ◽  
Rana Sanyal ◽  
Amitav Sanyal
Keyword(s):  
Exchange Reaction ◽  
Functional Materials ◽  
Polymeric Materials ◽  
Disulfide Exchange ◽  
Redox Responsive ◽  
Synthetic Approaches

This review provides an overview of synthetic approaches utilized to incorporate the thiol-reactive pyridyl-disulfide motif into various polymeric materials, and briefly highlights its utilization to obtain functional materials.

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