Zuanru Yuan

Thermal, damping, and mechanical properties of thermosetting epoxy-modified asphalts

Epoxy-modified asphalts (epoxy asphalts) have been widely used in the pavements of orthotropic steel bridge deck. In this paper, several effects on the properties of epoxy asphalts have been investigated in detail. First, the addition of asphalts showed no significant effects on the curing reaction and the glass transition temperature of epoxy resin. Second, the damping properties of epoxy asphalts were increased with the addition of asphalt contents. Furthermore, mechanical results showed that the stress at yield, stress at break, and tensile modulus of epoxy asphalts decreased with the increase of asphalt contents, whereas the strain at break increased with the increasing asphalt contents. The morphology of phase separation for epoxy asphalts was also observed.

Thermal, mechanical, and morphological properties of soybean oil-based polyurethane/epoxy resin interpenetrating polymer networks (IPNs)

A series of interpenetrating polymer networks (IPNs) based on epoxy (EP) resin and polyurethane (PU) prepolymer derived from soybean oil-based polyols with different mass ratios were synthesized. The structure, thermal properties, damping properties, tensile properties, and morphology of soybean oil-based PU/EP IPNs were characterized by Fourier-transform infrared spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), universal test machine, and scanning electron microscopy (SEM). DSC and DMA results show that the glass transition temperature of the soybean oil-based PU/EP IPN decreases with the increase of PU prepolymer contents. Soybean oil-based PU/EP IPNs have better damping properties than that of the pure epoxy resin. The tensile strength and modulus of PU/EP IPNs decrease, while elongation at break increases with the increase of PU prepolymer contents. SEM observations reveal that phase separation appears in PU/EP IPNs with higher PU prepolymer contents.

Effects of Mn doping on structural and magnetic properties in NdFeB nanocomposites

Abstract The magnetic and structural properties of nanocomposite Nd 9 Fe 85− x Mn x B 6 ( x =0,0.5,1) have been investigated. It was found that the addition of manganese in the Nd 9 Fe 85 B 6 could promote crystallization and enhance the hard magnetic properties of the material. Thermomagnetic analysis (TMA) measurement indicated that the doping of Mn reduces the T c of the Nd 2 Fe 14 B phase and raises that of α-Fe phase in the system. From the radial distribution curves around Fe atoms of Extended X-ray absorption fine structure (EXAFS), it has been demonstrated that for both the as-spun Nd 9 Fe 85− x Mn x B 6 ( x =0,0.5,1) samples with lower x value and the annealed samples, the EXAFS curves appear to be similar to that of α-Fe.