scholarly journals Reinforcement of Natural Rubber with Core-Shell Structure Silica-Poly(Methyl Methacrylate) Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Qinghuang Wang ◽  
Yongyue Luo ◽  
Chunfang Feng ◽  
Zhifeng Yi ◽  
Quanfang Qiu ◽  
...  

A highly performing natural rubber/silica (NR/SiO2) nanocomposite with a SiO2loading of 2 wt% was prepared by combining similar dissolve mutually theory with latex compounding techniques. Before polymerization, double bonds were introduced onto the surface of the SiO2particles with the silane-coupling agent. The core-shell structure silica-poly(methyl methacrylate), SiO2-PMMA, nanoparticles were formed by grafting polymerization of MMA on the surface of the modified SiO2particles via in situ emulsion, and then NR/SiO2nanocomposite was prepared by blending SiO2-PMMA and PMMA-modified NR (NR-PMMA). The Fourier transform infrared spectroscopy results show that PMMA has been successfully introduced onto the surface of SiO2, which can be well dispersed in NR matrix and present good interfacial adhesion with NR phase. Compared with those of pure NR, the thermal resistance and tensile properties of NR/SiO2nanocomposite are significantly improved.

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1201
Author(s):  
Xinghua Ji ◽  
Cheng Zhang ◽  
Shufeng Li

SiCp reinforced aluminium matrix composites (AMCs), which are widely used in the aerospace, automotive, and electronic packaging fields along with others, are usually prepared by ex situ techniques. However, interfacial contamination and poor wettability of the ex situ techniques make further improvement in their comprehensive performance difficult. In this paper, SiCp reinforced AMCs with theoretical volume fractions of 15, 20, and 30% are prepared by powder metallurgy and in situ reaction via an Al-Si-C system. Moreover, a combined method of external addition and an in situ method is used to investigate the synergistic effect of ex situ and in situ SiCp on AMCs. SiC particles can be formed by an indirect reaction: 4Al + 3C → Al4C3 and Al4C3 + 3Si → 3SiC + 4Al. This reaction is mainly through the diffusion of Si, in which Si diffuses around Al4C3 and then reacts with Al4C3 to form SiCp. The in situ SiC particles have a smooth boundary, and the particle size is approximately 1–3 μm. A core-shell structure having good bonding with an aluminium matrix was generated, which consists of an ex situ SiC core and an in situ SiC shell with a thickness of 1–5 μm. The yield strength and ultimate tensile strength of in situ SiCp reinforced AMCs can be significantly increased with a constant ductility by adding 5% ex situ SiCp for Al-28Si-7C. The graphite particle size has a significant effect on the properties of the alloy. A criterion to determine whether Al4C3 is a complete reaction is achieved, and the forming mechanism of the core-shell structure is analysed.


2011 ◽  
Vol 71-78 ◽  
pp. 928-931
Author(s):  
Jin Liang Wu ◽  
Yong Xing Zhang ◽  
Chun Sun Zhang

Nowadays, there are dominantly two ways of producing modified emulsified asphalt ,one of which is to emulsify modified asphalt, the other to modify asphalt emulsion. But they have the same defect that modifier cannot be evenly mixed with asphalt emulsion, which has side effect on the performance of modified emulsified asphalt. The emulsified asphalt and modifier have different traits in structure and property. In order to make the modifier disperse in asphalt emulsion evenly to improve the performance of modified emulsified asphalt, a tentative idea is brought forward: we shall utilize in-situ polymerization and core-shell structure to enhance feature of emulsified asphalt. Core-shell structure is a method of synthesizing composite material, which can assist to achieve sound effect of the two kinds of materials. The point to emphasize is, in this paper, the introduction and feasibility of the method, its specialty against current mainly methods, the difficulties encountered in practice as well as its promising prospect and the anticipated target to achieve will all be illustrated.


2019 ◽  
Vol 35 (14) ◽  
pp. 1727-1734
Author(s):  
Lisheng Zhong ◽  
Haiqiang Bai ◽  
Junzhe Wei ◽  
Jianlei Zhu ◽  
Jianhong Peng ◽  
...  

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