scholarly journals Monolithic zirconia aerogel from polyacetylacetonatozirconium precursor and ammonia hydroxide gel initiator: formation mechanism, mechanical strength and thermal properties

RSC Advances ◽  
2018 ◽  
Vol 8 (72) ◽  
pp. 41603-41611 ◽  
Author(s):  
Benxue Liu ◽  
Min Gao ◽  
Xiaochan Liu ◽  
Yongshuai Xie ◽  
Xibin Yi ◽  
...  

Large-sized, high-transparent and monolithic ZrO2 aerogel was prepared by a synthetic zirconium precursor.

2017 ◽  
Vol 43 (18) ◽  
pp. 16210-16216 ◽  
Author(s):  
Chonghe Xu ◽  
Kangkang Yuan ◽  
Xiaotong Jin ◽  
Zhichao Yu ◽  
Lei Zheng ◽  
...  

2016 ◽  
Vol 22 (2) ◽  
pp. 281-299 ◽  
Author(s):  
Kamaljit Singh Boparai ◽  
Rupinder Singh ◽  
Harwinder Singh

Purpose The purpose of this study is to highlight the direct fabrication of rapid tooling (RT) with desired mechanical, tribological and thermal properties using fused deposition modelling (FDM) process. Further, the review paper demonstrated development procedure of alternative feedstock filament of low-cost composite material for FDM to extend the range of RT applications. Design/methodology/approach The alternative materials for FDM and their processing requirements for fabrication in filament form as reported by various researchers have been summarized. The literature demonstrates the role of various post-processing techniques on surface finish of FDM prints. Further, low-cost materials for feedstock filament have been investigated experimentally to check their adaptability/suitability for commercial FDM setup. The approach was to realize the requirements of FDM (melt flow rate, flexibility, stiffness, glass transition temperature and mechanical strength), necessary for the successful run of an alternative filament. The effect of constituents (additives, plasticizers, surfactants and fillers) in polymeric matrix on mechanical, tribological and thermal properties has been investigated. Findings It is possible to develop composite material feedstock as filament for commercial FDM setup without changing its hardware and software. Surface finish of the parts can further be improved by applying various post-processing techniques. Most of the composite parts have high mechanical strength, hardness, thermal stability, wear resistant and better bond formation than standard material parts. Research limitations/implications Future research may be focused on improving the surface quality of parts fabricated with composite feedstock, solving issues related to the uniform distribution of filled materials during the fabrication of feedstock filament which in turns further increases mechanical strength, high dimensional stability of composite filament and transferring the technology from laboratory scale to various industrial applications. Practical implications Potential applications of direct fabrication with RT includes rapid manufacturing (RM) of metal-filled parts and ceramic-filled parts (which have complex shape and cannot be rapidly made by any other manufacturing techniques) in the field of biomedical and dentistry. Originality/value This new manufacturing methodology is based on the proper selection and processing of various materials and additives to form high-performance, low-cost composite material feedstock filament (which fulfil the necessary requirements of FDM process). Finally, newly developed feedstock filament material has both quantitative and qualitative advantage in RT and RM applications as compared to standard material filament.


Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3047 ◽  
Author(s):  
Young Shin Kim ◽  
Jae Kyung Kim ◽  
Euy Sik Jeon

Among the composite manufacturing methods, injection molding has higher time efficiency and improved processability. The production of composites via injection molding requires a pre-process to mix and pelletize the matrix polymer and reinforcement material. Herein, we studied the effect of extrusion process conditions for making pellets on the mechanical and thermal properties provided by injection molding. Polyamide 6 (PA6) was used as the base, and composites were produced by blending carbon fibers and Al2O3 as the filler. To determine the optimum blending ratio, the mechanical properties, thermal conductivity, and melt flow index (MI) were measured at various blending ratios. With this optimum blending ratio, pellets were produced by changing the temperature and RPM conditions, which are major process variables during compounding. Samples were fabricated by applying the same injection conditions, and the mechanical strength, MI values, and thermal properties were measured. The mechanical strength increased slightly as the temperature and RPM increased, and the MI and thermal conductivity also increased. The results of this study can be used as a basis for specifying the conditions of the mixing and compounding process such that the desired mechanical and thermal properties are obtained.


Soft Matter ◽  
2011 ◽  
Vol 7 (9) ◽  
pp. 4284 ◽  
Author(s):  
Qian Zhao ◽  
Jianzhong Sun ◽  
Xiaofei Wu ◽  
Yuteng Lin

e-Polymers ◽  
2014 ◽  
Vol 14 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Huifang Zhao ◽  
Yinbang Zhu ◽  
Lizheng Sha

AbstractFiber classification of aramid fibrids was carried out using a Bauer-McNett fiber classifier, and the molecular weight and thermal properties of different sizes of aramid fibrids were determined with viscometry and differential scanning calorimetry (DSC), respectively. Aramid handsheets were made from different sizes of aramid fibrids and aramid short fibers, and the relationship between mechanical strength of aramid handsheets and thermal properties of aramid fibrids was examined. In addition, aramid papers from four different sources were also investigated to elucidate the relationship between their thermal properties and mechanical strength. It was found that aramid fibrids passing through 30-mesh screens and remaining on 50-mesh screens and aramid fibrids with narrower molecular weight distribution are suitable for the production of high-strength aramid papers. Lower crystallinity and wider molecular weight distribution are important contributors to the lower mechanical strength of domestic aramid paper when compared to that of Nomex paper.


1991 ◽  
Vol 6 (2) ◽  
pp. 401-406 ◽  
Author(s):  
Tariq Iqbal ◽  
Mahmoud R. Shahriari ◽  
Glenn Merberg ◽  
George H. Sigel

Fluorozirconate glasses are stable with respect to devitrification but have poor chemical durability and only fair mechanical strength. AlF3-based glasses with improved chemical durability and enhanced mechanical strength are reported here. The optical, mechanical, and thermal properties of these glasses are contrasted to the more familiar ZBLAN composition. The infrared edge of these glasses lies at shorter wavelengths than ZrF4-based glasses, but aluminum fluoride glasses offer some interesting opportunities for short-range IR fiber applications such as sensing, remote spectroscopy, and laser power propagation.


2014 ◽  
Vol 896 ◽  
pp. 263-266
Author(s):  
Sutikno ◽  
Putut Marwoto ◽  
Ajeng Dian Puspita

The starch of artocarpus heterophyllus lam seeds was mixed with distilled water into a solution. The biodegradable plastics were made of starch, glycerol, and chitosan on the different volume fraction of glycerol at mixing temperature 80°C. The effect of glycerol addition on the microstructures, crystal structures, mechanical strength and thermal properties of specimens are completely reported. They were prepared based on the different volume fraction of glycerol, i.e., 2, 4 dan 6 (%Vol). The crystal structures of biodegradable plastic films were investigated using x-ray diffractometer and their thermal properties were analyzed employing thermogravimetric analysis. The biodegradabilities of specimens were obtained by soil burial test method using microorganisms. The maximum mechanical strength of biodegradable plastics is obtained about 4,7 MPa.


RSC Advances ◽  
2014 ◽  
Vol 4 (60) ◽  
pp. 31666 ◽  
Author(s):  
Liang Zhong ◽  
Xiaohong Chen ◽  
Huaihe Song ◽  
Kang Guo ◽  
Zijun Hu

2015 ◽  
Vol 124 (1) ◽  
pp. 197-203 ◽  
Author(s):  
M. Imiela ◽  
R. Anyszka ◽  
D. M. Bieliński ◽  
Z. Pędzich ◽  
M. Zarzecka-Napierała ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2372
Author(s):  
Waqas Ahmad ◽  
Qaizar Ahmad ◽  
Muhammad Yaseen ◽  
Imtiaz Ahmad ◽  
Fida Hussain ◽  
...  

The current study reports the effect of different wt. ratios of copper oxide nanoparticle (CuO-NPs) and reduced graphene oxide (rGO) as fillers on mechanical, electrical, and thermal properties of waste polystyrene (WPS) matrix. Firstly, thin sheets of WPS-rGO-CuO composites were prepared through solution casting method with different ratios, i.e., 2, 8, 10, 15 and 20 wt.% of CuO-NPs and rGO in WPS matrix. The synthesized composite sheets were characterized by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The electrical conductance and mechanical strength of the prepared composites were determined by using LCR meter and universal testing machine (UTM). These properties were dependent on the concentrations of CuO-NPs and rGO. Results display that the addition of both fillers, i.e., rGO and CuO-NPs, collectively led to remarkable increase in the mechanical properties of the composite. The incorporation of rGO-CuO: 15% WPS sample, i.e., WPS-rGO-CuO: 15%, has shown high mechanical strength with tensile strength of 25.282 MPa and Young modulus of 1951.0 MPa, respectively. Similarly, the electrical conductance of the same composite is also enhanced from 6.7 × 10−14 to 4 × 10−7 S/m in contrast to WPS at 2.0 × 106 Hz. The fabricated composites exhibited high thermal stability through TGA analysis in terms of 3.52% and 6.055% wt. loss at 250 °C as compared to WPS.


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