Microwave-assisted foaming and sintering to prepare lightweight high-strength polystyrene/carbon nanotubes composite foams with an ultralow percolation threshold

2021 ◽  
Author(s):  
Yeping Xie ◽  
Zhao Li ◽  
Jiahong Tang ◽  
Pan Li ◽  
Wenhua Chen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Percolation Threshold ◽  
Energy Saving ◽  
Polymer Composite ◽  
High Strength ◽  
High Tech ◽  
Microwave Assisted ◽  
Composite Foams

Lightweight, high-strength, and multifunctional polymer composite foams are urgently needed in various high-tech areas. Herein, we proposed a facile, clean, and energy-saving strategy to prepare the microcellular polystyrene/carbon nanotubes (PS/CNTs)...

Electrical Conductivity and Elastic Properties of Carbon Nanotube Reinforced Polycarbonate Nanocomposites

2011 ◽  
Author(s):  
Yves Ngabonziza ◽  
Jackie Li
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Percolation Threshold ◽  
Elastic Properties ◽  
Experimental Testing ◽  
High Strength ◽  
Effective Elastic Modulus ◽  
Injection Velocity ◽  
Micromechanics Models ◽  
Multi Walled Carbon Nanotubes

In the past years, carbon nanotubes and their composites have been intensively studied due to their extremely high strength and high electrical and thermal conductivities. However, to be able to use CNT-reinforced composites as structural materials in real applications, more cost-efficient processing methods should be adopted and the properties of such nanocomposites need to be further analyzed. Here we investigate the electrical and elastic properties of multi-walled carbon nanotubes (MWCNT) reinforced polycarbonate (PC) nanocomposites produced by injection molding which has been widely used in industrial plastic production. Nanocomposite samples with MWCNT ranging from 0 to 7wt% were tested for both electrical conductivity using a 2-probe measurement and mechanical properties under tensile loading. It has been found that the electrical conductivity depends on both injection velocity and the CNT content while the elastic properties of the nanocomposites only depend on the CNT content. Besides the experimental testing, a percolation theory and micromechanics models have been applied to determine the electrical conductivity percolation threshold and the effective elastic modulus of the nanocomposites in terms of CNT contents. The results are compared with our experimental data. It shows that a percolation threshold is around 1.8wt% of MWCNT. The evaluation of elastic properties using micromechanics models not only indicates the influence of MWCNT on elastic properties but also the presence of an interphase between the CNT and PC matrix.

ANALYSIS OF WORK ON NANOSTRUCTURED MATERIALS IN ORTHOPEDIC DENTISTRY UNDER THE DIRECTION OF PROFESSOR E.S. KALIVRADZHIYAN

2020 ◽  
pp. 8-13
Author(s):  
Жанна Владимировна Вечеркина ◽  
Наталия Владимировна Чиркова ◽  
Михаил Анатольевич Крючков ◽  
Виктор Сергеевич Калиниченко
Keyword(s):  
Nanostructured Materials ◽  
Dental Materials ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Barrier Properties ◽  
Working Time ◽  
Polymerization Process ◽  
High Tech ◽  
Acrylic Polymer ◽  
Removable Plate

Развитие технологий, основанных на использовании низкотоксичных материалов, позволит в скором будущем начать их применение в медицине. Применение наночастиц серебра, меди, кремния, цинка, титана, кобальта в качестве модифицирующей добавки позволит оказать активное влияние на структуру исходных материалов и изменение их свойств, а именно улучшение физико-механических, физико-химических и токсико-гигиенических свойств материалов. Наноразмерные частицы кремния, введенные в фиксирующие стоматологические материалы, приводят к улучшению физико-химических, физико-механических свойств кристаллизующихся материалов, а малая теплопроводность кремния может увеличить его рабочее время и снизить выделение тепла при реакции кристаллизации. Так как от этих характеристик зависит объем манипуляций, при фиксации ортопедических конструкций на опорных зубах целесообразно было бы привести рабочее время твердения к чистому времени твердения, что позволит увеличить объем манипуляций приготовленной массой без ухудшения ее свойств. Разработка высокопрочных, биосовместимых, высокотехнологичных нанопластмасс для базисов съемных пластиночных протезов является актуальной проблемой повышения качества жизни пациентов. Модификация наноразмерными частицами серебра, кремния акрилового полимера позволит улучшить такие физико-механические свойства, как ударную вязкость, прочность, температуростойкость, барьерные свойства, уменьшить усадку полимера на этапе полимеризации, в отличие от уже известных отечественных и дорогостоящих импортных полимеров. Наноразмерные частицы кремния, серебра являются сокатализаторами метилметакрилата, влияющими на уменьшение количества остаточного мономера после процесса полимеризации, тем самым повышая санитарно-химические и токсико-гигиенические характеристики полимера. Все вышеизложенное позволило сформулировать цель исследований по наноструктурированным материалам под руководством профессора …посвящается памяти профессора, д.м.н. Каливраджияна Э.С. The development of technologies based on the use of low-toxic materials will make it possible to begin their application in medicine in the near future. The use of nanoparticles of silver, copper, silicon, zinc, titanium, cobalt as a modifying additive will make it possible to actively influence the structure of the starting materials and change their properties, namely, improve the physicomechanical, physicochemical and toxicohygienic properties of materials. Nanosized silicon particles introduced into fixing dental materials lead to an improvement in the physicochemical, physicomechanical properties of crystallizing materials, and the low thermal conductivity of silicon can increase its working time and reduce heat generation during the crystallization reaction. Since the volume of manipulations depends on these characteristics, when fixing orthopedic structures on abutment teeth, it would be advisable to bring the working time of hardening to a pure hardening time, which will increase the volume of manipulations with the prepared mass without deteriorating its properties. The development of high-strength, biocompatible, high-tech nanoplastics for the bases of removable plate prostheses is an urgent problem to improve the quality of life of patients. Modification of acrylic polymer with nano-sized particles of silver and silicon will improve such physical and mechanical properties as impact strength, strength, temperature resistance, barrier properties, and reduce polymer shrinkage at the stage of polymerization, in contrast to the already known domestic and expensive imported polymers. Nanosized particles of silicon, silver are cocatalysts of methyl methacrylate, affecting the reduction of the amount of residual monomer after the polymerization process, thereby increasing the sanitary-chemical and toxic-hygienic characteristics of the polymer. All of the above made it possible to formulate the goal of research on nanostructured materials under the guidance of the professor …dedicated to the memory of the professor, d.m.s. Kalivrajiyan E.S.

scholarly journals Utilization of Polymer Concrete Composites for a Circular Economy: A Comparative Review for Assessment of Recycling and Waste Utilization

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2135
Author(s):  
Hatem Alhazmi ◽  
Syyed Adnan Raheel Shah ◽  
Muhammad Kashif Anwar ◽  
Ali Raza ◽  
Muhammad Kaleem Ullah ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Polymer Composite ◽  
Circular Economy ◽  
Agricultural Waste ◽  
High Strength ◽  
Supplementary Cementitious Materials ◽  
Polymer Concrete ◽  
Promising Alternative ◽  
Detailed Review ◽  
Comparative Review

Polymer composites have been identified as the most innovative and selective materials known in the 21st century. Presently, polymer concrete composites (PCC) made from industrial or agricultural waste are becoming more popular as the demand for high-strength concrete for various applications is increasing. Polymer concrete composites not only provide high strength properties but also provide specific characteristics, such as high durability, decreased drying shrinkage, reduced permeability, and chemical or heat resistance. This paper provides a detailed review of the utilization of polymer composites in the construction industry based on the circular economy model. This paper provides an updated and detailed report on the effects of polymer composites in concrete as supplementary cementitious materials and a comprehensive analysis of the existing literature on their utilization and the production of polymer composites. A detailed review of a variety of polymers, their qualities, performance, and classification, and various polymer composite production methods is given to select the best polymer composite materials for specific applications. PCCs have become a promising alternative for the reuse of waste materials due to their exceptional performance. Based on the findings of the studies evaluated, it can be concluded that more research is needed to provide a foundation for a regulatory structure for the acceptance of polymer composites.

scholarly journals Editorial for Special Issue “Leaching of Rare Earth Elements from Various Sources”

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 164
Author(s):  
Kenneth N. Han
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
High Strength ◽  
Green Energy ◽  
High Tech ◽  
Special Issue ◽  
Important Group ◽  
Military Applications

Rare earth elements (REEs) have become an important group of metals used in many high-tech industries, including high-strength magnets, plasma TVs, various military applications, and clean and efficient green energy industries [...]

scholarly journals Soil microbiomes mediate degradation of vinyl ester-based polymer composites

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Adam M. Breister ◽  
Muhammad A. Imam ◽  
Zhichao Zhou ◽  
Md Ariful Ahsan ◽  
Juan C. Noveron ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Polymer Composite ◽  
Structural Integrity ◽  
Abiotic Factors ◽  
High Strength ◽  
Strength Properties ◽  
Naturally Occurring ◽  
Structural Applications ◽  
Acrylate Esters ◽  
Bacterial Groups

AbstractPolymer composites are attractive for structural applications in the built environment due to their lightweight and high strength properties but suffer from degradation due to environmental factors. While abiotic factors like temperature, moisture, and ultraviolet light are well studied, little is known about the impacts of naturally occurring microbial communities on their structural integrity. Here we apply complementary time-series multi-omics of biofilms growing on polymer composites and materials characterization to elucidate the processes driving their degradation. We measured a reduction in mechanical properties due to biologically driven molecular chain breakage of esters and reconstructed 121 microbial genomes to describe microbial diversity and pathways associated with polymer composite degradation. The polymer composite microbiome is dominated by four bacterial groups including the Candidate Phyla Radiation that possess pathways for breakdown of acrylate, esters, and bisphenol, abundant in composites. We provide a foundation for understanding interactions of next-generation structural materials with their natural environment that can predict their durability and drive future designs.

scholarly journals Progress in Research on Carbon Nanotubes Reinforced Cementitious Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Qinghua Li ◽  
Jintao Liu ◽  
Shilang Xu
Keyword(s):  
Carbon Nanotubes ◽  
Large Scale ◽  
High Strength ◽  
Cementitious Composites ◽  
Scale Production ◽  
Multiwalled Carbon ◽  
Factors Affecting ◽  
Environment And Health ◽  
Research Activities ◽  
Major Factors

As one-dimensional (1D) nanofiber, carbon nanotubes (CNTs) have been widely used to improve the performance of nanocomposites due to their high strength, small dimensions, and remarkable physical properties. Progress in the field of CNTs presents a potential opportunity to enhance cementitious composites at the nanoscale. In this review, current research activities and key advances on multiwalled carbon nanotubes (MWCNTs) reinforced cementitious composites are summarized, including the effect of MWCNTs on modulus of elasticity, porosity, fracture, and mechanical and microstructure properties of cement-based composites. The issues about the improvement mechanisms, MWCNTs dispersion methods, and the major factors affecting the mechanical properties of composites are discussed. In addition, large-scale production methods of MWCNTs and the effects of CNTs on environment and health are also summarized.

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