The influence of injection molding parameter on properties of thermally conductive plastic

Thermally conductive plastic is the composite between metal-plastic material that is becoming popular because if it special characteristic. Injection moulding was regarded as the best process for mass manufacturing of the plastic composite due to its low production cost. The objective of this research is to find the best combination of the injection parameter setting and to find the most significant factor that effect the strength and thermal conductivity of the composite. Several parameter such as the volume percentage of copper powder, nozzle temperature and injection pressure of injection moulding machine were investigated. The analysis was done using Design Expert Software by implementing design of experiment method. From the analysis, the significant effects were determined and mathematical models of only significant effect were established. In order to ensure the validity of the model, confirmation run was done and percentage errors were calculated. It was found that the best combination parameter setting to maximize the value of tensile strength is volume percentage of copper powder of 3.00%, the nozzle temperature of 195oC and the injection pressure of 65%, and the best combination parameter settings to maximize the value of thermal conductivity is volume percentage of copper powder of 7.00%, the nozzle temperature of 195oC and the injection pressure of 65% as recommended

Effect of graphene material structure and iron oxides deposition method on morphology and properties of graphene/iron oxide hybrids

In this work, various facile approaches were applied to prepare hybrids of graphene nanoplatelets (GNPs) and graphene oxide (GO) with iron oxides (IO) nanoparticles (NPs). The IO NPs were synthesized and deposited on the graphene surfaces via: (1) co-precipitation using Fe (II) and Fe (III) salts, (2) homogeneous precipitation of Fe2O3 from FeCl3 solution, (3) the attaching of Fe2O3 NPs functionalized with 3-aminopropyltrimethoxysilane to graphene surfaces of GO and GNPs. The effects of the graphene material and preparation procedure on the structural characteristics of the hybrids were studied. Their morphology was studied by scanning electron microscopy and transmission microscopy. Lattice parameters and crystallite sizes of the synthesized hybrid materials were assessed by X-ray diffraction. Raman spectroscopy was used to determine the change of order degree of graphene structures as a results of IO NPs deposition and interactions IO NPs with graphene sheets. Binding energy for IO NPs and graphene structures were determined by photoelectron X-ray spectroscopy. Thermogravimetric analysis was applied to find differences in the thermal stability of hybrids. The hybrids are proposed as nanofillers to polymer composites, however they have large potential applications as supercapacitors, advanced anode materials for lithium-ion batteries, magnetically targeted drug delivery, and magnetic resonance imaging

Thermal Conductivity of Carbon Nanotubes and their Polymer Nanocomposites: A Review

Thermally conductive polymer composites offer new possibilities for replacing metal parts in several applications, including power electronics, electric motors and generators, heat exchangers, etc., thanks to the polymer advantages such as light weight, corrosion resistance and ease of processing. Current interest to improve the thermal conductivity of polymers is focused on the selective addition of nanofillers with high thermal conductivity. Unusually high thermal conductivity makes carbon nanotube (CNT) the best promising candidate material for thermally conductive composites. However, the thermal conductivities of polymer/CNT nanocomposites are relatively low compared with expectations from the intrinsic thermal conductivity of CNTs. The challenge primarily comes from the large interfacial thermal resistance between the CNT and the surrounding polymer matrix, which hinders the transfer of phonon dominating heat conduction in polymer and CNT. This article reviews the status of worldwide research in the thermal conductivity of CNTs and their polymer nanocomposites. The dependence of thermal conductivity of nanotubes on the atomic structure, the tube size, the morphology, the defect and the purification is reviewed. The roles of particle/polymer and particle/particle interfaces on the thermal conductivity of polymer/CNT nanocomposites are discussed in detail, as well as the relationship between the thermal conductivity and the micro- and nano-structure of the composite

ВЗАИМОСВЯЗЬ МЕЖДУ СТРУКТУРОЙ, ЭЛЕКТРИЧЕСКИМИ И ДИЭЛЕКТРИЧЕСКИМИ СВОЙСТВАМИ ИОНОПРОВОДЯЩИХ ПОЛИМЕРНЫХ КОМПОЗИТОВ НА ОСНОВЕ ЭПОКСИДНЫХ ОЛИГОМЕРОВ И СОЛИ ПЕРХЛОРАТА ЛИТИЯ

Solid polymer electrolytes (SPE) have received a great attention to the decisive role as an ionic conductor in various electrochemical devices. Significant efforts have been devoted to the high ionic conductivity with better mechanical stability of SPE. The aim of this work is to investigate the relationship between structure, electrical and dielectric properties of the crosslinked ion-conducting polymers based on a mixture of oligomers with similar functional epoxy groups. The effect of lithium perchlorate salt content on structure and properties of the synthesized polymer systems based on aliphatic epoxy oligomer – diglycidylether of ethylene glycol DEG-1 and epoxy-diane resin ED-20, which were cured by polyethylene polyamine, has been studied by means of the Differential Scanning Calorimetry, the Wide Angle X-ray Diffraction and the Broadband Dielectric Spectroscopy. It was found that the glass transition temperature of the synthesized systems increases with increasing amount of the LiClO4 that is connected with formation of coordination complexes between lithium cations and atoms of macromolecular chains. Presence of one single diffraction maximum of the diffuse type, an angular value of which is approximately 19.6, on the wide angle X-ray diffractograms indicates that systems are amorphous and they are characterized by the short-range ordering. The real parts of permittivity and complex electrical conductivity depend on the content of lithium perchlorate salt and temperature of measurements. The maximum level of ionic conductivity and permittivity at elevated temperatures was revealed for the systems with a concentration 30 phr. of the lithium perchlorate salt. Твердые полимерные электролиты (ТПЭ) могут выступать в качестве ионопроводящего материала в различных электрохимических устройствах. Значительные усилия исследователей в области полимеров направлены на достижение высокой ионной проводимости одновременно с улучшенной механической стабильностью ТПЭ. Целью данной работы является исследование взаимосвязи между структурой, электрическими и диэлектрическими свойствами сшитого ионопроводящего полимера на основе смеси олигомеров, которые имеют сходные функциональные эпоксидные группы. Методами дифференциальной сканирующей калориметрии, широкоугловой дифракции рентгеновских лучей и широкополосной диэлектрической спектроскопии изучено влияние содержания соли перхлората лития на структуру и свойства полимерных систем, синтезированных на основе эпоксидного алифатического олигомера – диглицидилового эфира полиэтиленгликоля ДЭГ-1 и эпоксидиановой смолы ЭД-20, отверждение которых проводилось полиэтиленполиамином. Установлено, что температура стеклования синтезированных систем возрастает с увеличением количества соли LiClO4, что связано с образованием координационных комплексов между катионами лития и атомами макромолекулярных цепей ДЭГ-1 и ЭД-20. Присутствие на широкоугловой рентгеновской дифрактограмме одного дифракционного максимума диффузного типа, угловое значение которого составляет приблизительно 19,6, свидетельствует, что системы являются аморфными и характеризуются ближним порядком при трансляции в пространстве фрагментов их межузловых молекулярных звеньев. Действительные составляющие диэлектрической проницаемости и комплексной электрической проводимости зависят от содержания соли перхлората лития и температуры, при которой проводились измерения. Максимальный уровень ионной проводимости и диэлектрической проницаемости выявлен при повышенных температурах у систем, синтезированных с концентрацией соли перхлората лития 30 м. ч.

Electrical conductivity of natural rubber cellulose II nanocomposites

[EN] Nanocomposite materials obtained from natural rubber (NR) reinforced with different amounts of cellulose II (cell) nanoparticles (in the range of 0 to 30 phr) are studied by dielectric spectroscopy (DS) in a broad temperature range (¿150 to 150 °C). For comparative purposes, the pure materials, NR and cell, are also investigated. An analysis of the cell content effect on the conductive properties of the nanocomposites was carried out. The dielectric spectra exhibit conductivity phenomena at low frequencies and high temperatures: Maxwell¿Wagner¿ Sillars (MWS) and electrode polarization (EP) conductive processes were observed in the nanocomposite samples.We thank Professor Regina Nunes of the Instituto de Macromoleculas Eloisa Mano (Universidade Federal do Rio de Janeiro) for providing us the NR and NR-cell samples. This work was financially supported by DGCYT through grant MAT2012-33483.Ortiz Serna, MP.; Carsí Rosique, M.; Redondo Foj, MB.; Sanchis Sánchez, MJ. (2014). Electrical conductivity of natural rubber cellulose II nanocomposites. Journal of Non-Crystalline Solids. 405:180-187. https://doi.org/10.1016/j.jnoncrysol.2014.09.026S18018740