Studies On Synthesis And Properties Of Acrylonitrile-EPDM-styrene Graft Copolymer

Rapid prototyping (RP) technology is a new manufacturing method that was developed since 1980s. The FDM process of it is of great application prospect as it meets with the requests of variety and geometric complexity of products. The materials widely employed by RP technology are narrowly confined to wax, ABS resin. But the heat resistance of ABS is poor which had limited the further use of it. In this paper, EPDM was chosen as a substitution of butadiene and a new material -acrylonitrile-EPDM-styrene graft copolymer was gained for FDM .In this paper AES copolymer was synthesized in solution and was isolated from the copolymerization mixture with a Soxhlet extractor. Meanwhile FT-IR was used to certify the whole separation process. The effect of reaction time, initiator concentration, EPDM content and ratio of St to AN (in weight) on the solution copolymerization and graft parameters of the products were examined, and a graft copolymer with superior graft parameters was found. The Intrinsic-viscosity of AES was measured by viscosity method, and it's found that the Intrinsic-viscosity keeps a linear relationship with grafting ratio of the graft copolymer.The rheological behavior of copolymer AES in melt was investigated with the capillary flow measuring method, and it was found that copolymer AES had higher melted rheological behavior than ABS. As the result of the thermal decomposition analysis, the heat resistance sequence of the three is as follows: EPDM AES > ABS. Through the identification of mechanical properties, it can be concluded that both the impact and tensile strength of AES are prior to that of ABS, so AES is a material with balanced mechanical properties. Study with Dynamic Mechanical Analysis graphs, AES proves to have a compatible effect on the blends.AES was used in EPDM/SAN two-phase system as a compatibilizer. Though the observation under a Scanning Electron Microscopy (SEM) and particle diameter statistics analysis, it is found: with the addition of AES, the particle size of the dispersed rubber phase isdecreased, the particle size distribution becomes narrower. The impact strength is improved significantly as a result of the increasing compatibility provided by the adding of AES. The Dynamic Mechanical Analysis of the blends has confirmed these conclusions.The thermal decomposition of AES and ABS is studied by means of thermal analysis via Freeman-Carroll and integral method separately. Both the apparent activation energy and the order of reaction of thermal decomposition of AES are significantly higher than that of ABS. The result shows that the thermal stability of AES is greatly improved. It revealed the mechanism of the enhancement of AES's thermal stability.It is found that the copolymer AES and EPDM/SAN/AES blends have mechanical properties and Theological behavior prior to ABS, and the decomposition temperature of AES is apparently higher than that of ABS. So both grafting AES and AES blends are to be materials with great prosperity in the field of RP technology.