Papers by Author: Ming Yi Wang

Abstract: In this work pyromellitic dianhydride (PMDA) was used as the chain extender to increase the molecular weight of the recycled poly(ethylene terephthalate) (R-PET) and improve the rheological properties of the R-PET. The reaction was performed in a Brabender torque rheometer. The rheological and thermal characterization were performed by means of a fusion index instrument and a differential scanning calorimeter (DSC ) to compare the effectiveness of the chain extending reaction of different percentages of PMDA. The experimental results showed that compared with the unmodified R-PET, the addition of PMDA decreased the melt flow index and increased the viscosity of the R-PET. In addition, increased crystallization temperatures ( ) were observed with the modified R-PET. It was also found that the modified R-PET with the concentration of 1.0wt% PMDA exhibited the lowest MFI.

Abstract: A challenge method composed of digital image correlation (DIC) method, circle coordinate grid technology and finite element (FE) software to conduct strain measurement of bimetal is presented. This approach can carry out the prediction and measurement of strain. The coordinate grids are painted on top and bottom surface of bimetal when experiment and simulate specimen. Each node is named a fixed number in turn, and these numbers can precisely help to identify the same name point between FE software and the experiments specimen. The bimetal sheet has been tested using DIC software, circle center of the coordinates points can be accurately identify on the surface of bimetal. The changing of distance between adjacent points is computed to construct the forming limit diagram before and after forming. It is an effective means to evaluate the forming performance of bimetal and verify the reasonable of FE analysis results. 2A12 metal is conducted experiment using the challenge method in this paper, bimetal has not conduct experiment due to some reasons.

Abstract: The effect of PDMS on foamability of R-PP was investigated using a single screw extrusion foaming system, with supercritical carbon dioxide as the blowing agent. Experimental results indicate that the addition of a small amount of PDMS will improve expansion ratio of R-PP foamed samples. Furthermore, compared with pure R-PP, cell-population density of foamed samples obtained from R-PP/PP-g-MAH/PDMS blends was obviously higher than that of pure R-PP foams.The experimental results show that blending with PDMS is beneficial for improving foaming performance of R-PP.