Liu Jiesheng

Experimental research in the phase change materials based on paraffin and expanded perlite

ABSTRACT In this study, paraffin (PA)/expanded perlite (EP) form-stable phase change material (PCM) was first fabricated using the direct impregnation method without vacuum treatment. Absorptive capacity results showed that the PA/EP composite can obtain good absorptive capacity with the temperature 80 °C and the time 2 h. Compared with the water absorption of EP, the decrease in the water absorption of PA/EP form-stable proved that the absorption of PA into porous EP has been carried out successfully. Scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) results show that paraffin can be well impregnated into EP pores and has good compatibility with it. Differential scanning calorimetry (DSC) results reveal that paraffin/EP composite PCM has melting temperature and latent heat of 53.6 °C and 91.3 J/g, respectively. The durability cycles results suggest that form-stable PA/EP PCM shows good durability.

Study on the Properties and Mechanism of Mortars Modified by Super Absorbent Polymers

The article investigated the influence of Super Absorbent Polymers (SAPs) with absorption behaviors on the consistency, fluidity, water absorption, mechanical properties, early crack resistance, permeability resistance, and degree of hydration of cementitious construction materials. Mechanical strength was investigated using a flexural and compressive strength test machine. Nonevaporable water content was employed to assess the degree of hydration of the cement powders. The durability of mortar was characterized using early crack resistance and a permeability resistance test. Furthermore, the micromechanism of mortars modified by SAPs and control mortars was researched using a Scanning Electron Microscope (SEM). Experimental results showed that for the SAPs and mix designs used in this article, the incorporation of SAPs generally reduced the mechanical strength and increased the consistency, fluidity, water absorption, and degree of hydration of modified mortars compared with control mortars. The durability of mortars incorporating SAPs was greatly improved. The connection of the macroproperty and micromechanism of mortars was researched using an SEM.

Preparation and characterization of a microemulsion via polycondensation of alkoxyl silane

A microemulsion was successfully prepared via polycondensation of alkoxy silanes. Research into the control of the preparation and properties of the microemulsion was conducted. The structure and properties of the microemulsion were characterized by transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS). The variation in the temperature, the methods, and the amount of catalyst and surfactant was studied in relation to the properties of the final microemulsion.

Properties of Polymer-Modified Mortar Using Silane as an Integral Additive

In the present paper, the addition of silane to improve the properties of mortar was experimentally investigated. The morphology and microstructure of mortar were investigated by using both scanning electron microscopy (SEM) and polarizing microscopy (PM). The results show that silane significantly alters the microstructure of mortar, reduces the crystallization, restricts the degree of hydration of cement-based materials, and decreases micro-voids. As a result, silane effectively improves the chemical and carbonation resistance, as well as the chloride and water penetration resistance of mortar. Results also indicate that the consistency of mortar was improved but the compressive strength of the mortar was decreased. Specifically, silane would also be beneficial to the bridging cracking function to resist crack propagation.