Tianming Gao

Use of Rubber Process Analyzer for Characterizing the Molecular Weight Parameters of Natural Rubber

The aim of this work is to introduce a simple and rapid method for characterizing the molecular weight parameters and other molecular structure parameters of natural rubber (NR) using a rubber process analyzer (RPA). In this work, NR of different molecular weights was prepared by milling. Molecular weight parameters were measured by gel permeation chromatography coupled with laser light scattering (GPC-LLS) for comparison with RPA results. It was verified that increasing of milling time leads to a decrease of the number-average molecular weight (), weight-average molecular weight (), and molecular weight distribution (MWD). The dynamic and rheological properties were evaluated on RPA by tests of strain sweep, frequency sweep, and stress relaxation. These results were used to characterize the average molecular weight, MWD, and viscosity of NR and were found to agree with those from GPC-LLS. This convenient and rapid technology for characterizing NR molecular weight parameters would be especially useful in the elastomer industry.

Interfacial Adhesion and Mechanical Properties of Magneto-rheological Elastomer Based on the Natural Rubber with Different Curing System

Vulcanization is an important procedure for elastomers processing. The effects of vulcanization system on the interfacial interaction and mechanical properties of magneto-rheological elastomers (MREs) based on natural rubber (NR) have not been researched, even though, there were many researches focusing on the natural rubber based MREs. In this work, sulfur and dicumyl peroxide (DCP) acted as curing agents preparing MREs based on NR. Scanning electron microscopy was used to characterize the interfacial adhesion of carbonyl iron particles (CIPs) in the matrix. Crosslink density provided evidence that the MREs with DCP system had higher crosslink density than that of MREs with sulfur system. The tensile strength of MREs with DCP system increased, while that of MREs with sulfur system decreased, when 30 vol% of CIPs filled into NR. Finally, the magneto-induced dynamic mechanical properties were tested using a modified dynamic thermo-mechanical analysis under magnetic fields.

Preparation and antibacterial property evaluation of TiO 2 /nature rubber nanocomposites

Nano-TiO<inf>2</inf> was prepared by sol-gel technology. The results displayed that the particle size of modified TiO<inf>2</inf> was less than 20 nm, and that of the unmodified TiO<inf>2</inf> was about 30nm; XRD analysis confirmed the TiO<inf>2</inf> made from sol-gel method was anatase type. TiO<inf>2</inf>/NR nanocomposites were found to possess excellent antibacterial and antifungal effects.