Wang Yanbing

The Dynamic Mechanical Properties of Chlorobutyl Rubber/Polybutyl Methacrylate Sequential Interpenetrating Networks

We report the dynamic mechanical and thermaldecomposition behavior of chlorobutyl rubber/polybutyl methacrylate sequential interpenetrating networks (CIIR/PBMA SIPNs). By varying the swelling time in solution of butyl methacrylate and BPO, CIIR/PBMA SIPNs with different composition (20%, 26% and 44% PBMA) were obtained. The IPNs show broader temperature distribution in loss factor. For IPNs with 44% PBMA, tan δ above 0.3 from −49°C to 104°C was observed. We also calculated the temperature shift factor (αT) using WLF equation at a given temperature region. Thermogravimetric analysis revealed that initial decomposition temperature and decompostion rate decreases with increase in PBMA concentration.

Experimental Investigation on the Damping Behaviors of Epoxies with Different Epoxy Value

In this article, five different epoxies including a new kind of flexible epoxy having low glass transition temperatures (11 ∼ 28°C) were prepared using polyamine as curing agent. Damping mechanical tests show that compared with other common available epoxies, the flexible epoxy has high loss factor over broad frequency and temperature range. Activation energy corresponding to glass transition process of different epoxies has been calculated from the temperature corresponding to tan δmax values, obtained at different measurement frequencies. The maximum value of loss factor is 0.71 and the Tg varies from 11 to 28°C, indicating the flexible epoxy can be used as damping polymer materials in common temperature or frequency range.

Mechanical and thermal properties of polysiloxanes and NBR blend elastomer

A series of elastomers, based on NBR, polysiloxanes (PS) were prepared and characterized by tensile tests, thermogravimetry (TG) and differential scanning calorimetry (DSC). Two kinds of vulcanizing agent, DMDBH (2,5-dimethyl-2,5-di(t-butyl perory) hexane) and DCP (dicumylperoxide) were used to investigate the influence of different vulcanizing agents on properties of PSINBR. The addition of PS to NBR was found to improve the thermal stability and decrease the tensile strength of NBR. The tensile strength decreased considerably while the elongation at break increased obviously with the increase of PS content. The series using DMD-BH as vulcanizing agent showed a higher tensile strength and elongation at break than the series using DCP as vulcanizing agent. Simultaneity the thermal stability increased with the increase of PS content.

Modification of nanocomposites by melting intercalation of polypropylene in montmorillonite

The polypropylene was modified by ultraviolet irradiation. The polypropylene-montmorillonite nanocomposites were prepared by direct melting intercalation of polypropylene powders. The structure of polypropylene, the polyproprlene irradiated, montmorillinote and polypropylene-montmorillonite composites were studied by XRD, IR and DSC. The results show that the PP molecules can are oxidized during ultraviolet irradiation, melt polypropylene can intercalate into montmorillonite layer. As a result, the layered distance (d001) of montmorillonite increases, and the melt absorption peak of polypropylene in layer is eliminated.