An experimental study of the bulk free radical polymerization of ethyl acrylate (EA) initiated by 2,2'-azoisobutyronitrile (AIBN) was conducted. The experiments were carried out based on a factorial design with replicates. The reaction variables investigated were initiator concentration, temperature and chain transfer agent (CTA) concentration (primary octanethiol). The results obtained were used to develop and test a simulation model for EA homopolymerization.
Monofunctional and bifunctional peroxides are extensively utilized in the production of polystyrene. However, their decomposition kinetics is still an important area to investigate. A computer package developed previously by Gao and Penlidis (1996), which was based on mono-functionally initiated polymerization, is extended in this study to cover homopolymerization of styrene using bifunctional initiators. A database of a wide variety of bifunctional peroxides used in polystyrene production is developed along with a database for twelve new monofunctional initiators. The package handles several different scenarios of styrene polymerization, whether it is in bulk I solution or isothermal I non-isothermal medium. The model is tested with a wide range of conversion and average molecular weight data either from the literature or available from industry. Simulation results agree with the data trends, which makes the simulator a very powerful tool in aid of initiator selection and evaluation. At the end of the paper, results on homopolymerizations of acrylates and methacrylates are also discussed. 299
Having been treated with coupling agent and pan‐milling, graphite is incorporated into HDPE to make a HDPE/graphite composite with enhanced thermal conductivity as well as good mechanical properties and processibility. This paper focuses on the study of mechanical properties, thermal stability and rheological behavior of HDPE/graphite composite. The experimental results show that with increase of the graphite content, Young's modulus of HDPE/graphite increases and the elongation at break and impact strength decrease. However, when the graphite content is 35% in HDPE/graphite, the elongation at break and impact strength still remain 22.4% and 85.8J/m. respectively. Also, the yield strength increases with the increase of the graphite content, and reaches the maximum at 55% graphite content, and reduces afterwards. The crystallization temperature and thermal stability of HDPE/graphite increase with the increase of the graphite content. The melt viscosity of the filled HDPE remains almost unchanged, but the shear sensitivity increases, and the temperature sensitivity decreases with the increase of the graphite content. By optimizing the experimental conditions, a HDPE/graphite composite with fairly good comprehensive properties such as enhanced thermal conductivity and stability, good mechanical properties, and processability could be prepared, which has potential application in the field of heat transfer.
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