Extrusion systems optimization

Branched PBT could be produced by reactive extrusion with multifunctional epoxide in a conventional extrusion system, after some initial experiments with an intensive batch mixer. The rheology of the reactive extrusion product could be controlled by material (amount of modifier) and operational (screw rpm and feed rate) conditions. Improved foamability could be attained by the reactive modification under the optimized extrusion conditions. 

A reported application of canonical analysis involved a novel combination of the canonical form of the regression equation with a computer-aided grid search technique to optimize controlled drug release from a pellet system prepared by extrusion and spheronization [28,29]. Formulation factors were used as independent variables, and in vitro dissolution was the main response, or dependent variable. Both a minimum and a maximum drug release rate was predicted and verified by preparation and testing of the predicted formulations. Excellent agreement between the predicted values and the actual values was evident for the four-component pellet system in this study. 

Hyun, K.S. and Spalding, M.A., Use of Process Data Obtained from a Data Acquisition System for Optimizing and Debugging Extrusion Processes, Adv. Polym. Tech., 15, 29 (1996)... 

Kiihn, R., Burkhardt, U., Heidemeyer, P, Optimization of quality and throughput at low revolution speeds in an advanced two stage compounding system, SPE/ANTEC Proceedings (2007), Extrusion Division, Paper No. 0392... 

We carried out experiments to define the optimal conditions in a reactive extrusion process, and to obtain maleic anhydride grafted polymers of polypropylene copolymers (3050 MN 4 supplied by ATOCHEM). The previous studies were carried out in a batch mixer (HAAKE RHEOCORD), at a temperature of 220° C and a mixing speed of 64 rpm, during 20 minutes. Three different systems were tested i. with pure maleic anhydride ii. in the presence of a solvent (toluene or chorobenzene) iii. by introduction... 

Fischer et al. (1997, 2006) have described an approach using combined NIR, Raman and ultrasound sensors with a melt-at-die interface for reactive extrusion. The system is shown in Figure 6.28, and it is noted that the combination of multiple sensors offers complementary information and allows optimization and choice of the best method for each... 

This work shows the acquired experience in the preparation at pilot-scale of a novel propane ammoxidation catalyst based on a partially nitrided V-Al mixed oxide obtained hy co-precipitation. A systematic investigation of the different parameters controlling the preparation of the catalyst via a co-precipitation route at different scales was carried out. At lab-scale (50 to 100 g), the preparation parameters optimized were precipitation pH, V/Al atomic ratio, V concentration in solution and nitridation conditions, while at pilot-scale (1 kg), the optimized parameters were precipitation and ageing time, solution/solid ratio during the washing step, drying and calcination conditions, and extrusion parameters. Our results show that the optimum preparation conditions for the VAION system are pH = 5.5, V/Al atomic ratio = 0.25, concentration of V species in solution = 30.10 M. This catalyst shows the highest selectivity and yield in acrylonitrile. The samples prepared at different scales show the same activity profile in the propane ammoxidation reaction. 

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