Preparation of hybrid composite microspheres containing nanosilicon via microsuspension polymerization

Abstract

Hybrid composite microspheres with nano-Si as the core and poly(styrene-co-acrylonitrile) as a shell are successfully prepared by a two-step polymerization technique, which includes dispersion polymerization of styrene and 3-methacryloxypropyl trimethoxysilane in ethanol for surface modification of nano-Si followed by microsuspension polymerization of styrene and acrylonitrile in an aqueous phase for encapsulating nano-Si into an SAN copolymer matrix. The structure and surface properties of modified nanoSi are investigated by Fourier transform infrared spectroscopy (FTIR) and contact angle. The hybrid composite microspheres are systematically characterized by energy dispersive spectroscopy, thermogravimetric analysis, and transmission electron microscopy (TEM). According to the FTIR spectra and the contact angle experiments, it was determined that a hydrophobic polymer layer was formed on the surface of nano-Si. TEM showed that nano-Si was homogeneously dispersed in SAN particles when the loading capacity of nano-Si in the hybrid composite microspheres was less than 20 wt %. Moreover, scanning electron microscopy and X-ray photoelectron spectroscopy revealed that there were large amounts of nano-Si absorbed on the surface of the hybrid composite microspheres, and the mean particle size became much larger when the loading amounts of nano-Si reached 25 wt %. From this, it can be inferred that nano-Si overflows from the inner core to the outside surface in the emulsification process and acts as an inorganic dispersant.

Blending poly(2‐ethyl‐2‐oxazoline) with hydrophobic polymers as a hybrid adhesive with enhancedwater‐resistantproperties

“…SAN is a randomly polymerized hydrophobic copolymer with different acrylonitrile ratios. 26,27 PVPh is a hydroxyl-containing polymer, implying good miscibility with proton-accepting polymers; and has been used as a water-resistant wood adhesive, 28 dielectric materials, 29,30 and antioxidant. 31,32 Both SAN and PVPh are amorphous polymers.…”

Si/CNTs@melamine‐formaldehyde resin‐based carbon composites and its improved energy storage performances

“…Therefore, many attentions have been paid on the development of various anode materials for the next‐generation lithium batteries with high specific capacities and long cyclic life. In particular, silicon (Si) has been regarded as one of the most promising anode materials, due to its high theoretical specific capacity (~3,572 mAh·g −1 in the form of Li 15 Si 4 ), low insertion voltage, and abundance in nature 3–5 . However, Si‐based electrodes suffer from poor high‐rate performances, severe electrode pulverization, and dramatic capacity fading during cycling, because of their poor intrinsic electrical conductivity and large volume change (~300%) during charging–discharging processes 6–8 …”

Preparation of the monodispersed carboxyl-functionalized polymer microspheres with disproportionated rosin moiety and adsorption of methylene blue

“…Polymer microspheres are new functional materials with some specific properties. Preparation and application of polymer microspheres have become an important research field in polymer science and have attracted the attentions of many researchers (Erdem and Bicak, 2016; Wei et al., 2016; Zhang et al., 2016) At present, primary methods of preparing polymer microspheres are suspension polymerization (Liu et al., 2016; Yu et al., 2014; Xie et al., 2017), emulsion polymerization (Fan et al., 2016; Yang et al., 2015; Zhang et al., 2012), dispersion polymerization (Beal et al., 2016; Zhang et al., 2011), and seed swelling polymerization (Srisopa, 2016; Xu et al., 2010). Dispersion polymerization is a relative new method for the preparation of monodispersed polymer microspheres with particle size ranging from 0.5 to 8.0 μm.…”