Effects of processing conditions

Processing temperature is one of the most important variables in the extrusion foaming process because it affects both the melt viscosity and the amount of gas given off upon the thermal decomposition of CFA [81-83]. However, high processing temperatures should be avoided due to the thermal instability of PLA. Similarly, lower melt temperature should not be used to prevent partial decomposition of the CFA. The extruder barrel temperature profile should be set up based on the melting temperature of the polymer and the decomposition temperature of CFA [86]. 

The extruder s rotational screw speed also affects the density of PLA foams. The density of foamed samples 

FIGURE 17.9 Effect of endothermic CFA (BIH40) content on the density of amorphous PLA 8302D foamed at 40 rpm. The extrusion processing temperatures were set at 180-180-175-170°C from the hopper to the die [86]. 

TABLE 17.10 Influence of Density on the Impact Strength of Unfoamed and Microcellnlar Foamed PLA [2] 

Traditionally, organoclay-polymer nanocomposites were synthesized by either the solution intercalation method or in-situ intercalative polymerization. However, it was the possibility of direct melt intercalation by 

Recently, Shahabadi and Garmabi [46] proposed the slurry-fed melt intercalation process to produce Mt-PE CPN and OMt PE CPN. In this novel process the polymer is introduced in the extruder and Na-t-Mt slurry is injected in the extruder and modified in an in-situ process, obtaining much improved exfoliation respect to the conventional methods. 

The nanocompomposites obtained are then processed by injection moulding or compression to obtain the mouldings. 

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Fig. 8-3 Example of the effect of processing conditions on impact for PP with different melt index flow behaviors.

Nanocomposite based on polyurethane (PU) is prepared using silica, clay, and Polyhedral Oligomeric Silsesquioxane (POSS). Preparation, characterization, mechanical and barrier properties, morphology, and effect of processing conditions have been reported on polyurethane-based nanocomposites [72,73]. 

Lv W, Luo Z, Yang H, Liu B, Weng W, Liu J (2010) Effect of processing conditions on sonochemical synthesis of nanosized copper aluminate powders. Ultrason Sonochem 17(2) 344—351... 

Bannayan, M. A., Fouling Mechanisms and Effect of Process Conditions on Deposit Formation in H-Oil Equipment, in Catalysts in Petroleum Refining and Petrochemical Industries, 1996. Kuwait, Studies in Surface Science and Catalysis, Elsevier. 100 pp. 273-281. 

In this work, a detailed kinetic model for the Fischer-Tropsch synthesis (FTS) has been developed. Based on the analysis of the literature data concerning the FT reaction mechanism and on the results we obtained from chemical enrichment experiments, we have first defined a detailed FT mechanism for a cobalt-based catalyst, explaining the synthesis of each product through the evolution of adsorbed reaction intermediates. Moreover, appropriate rate laws have been attributed to each reaction step and the resulting kinetic scheme fitted to a comprehensive set of FT data describing the effect of process conditions on catalyst activity and selectivity in the range of process conditions typical of industrial operations. 

Garg N, Churey JJ and Splittstoesser DF. 1990. Effects of processing conditions on the microflora of fresh-cut vegetables. J Food Prot 53 701-703. 

Tjeerdsma, B.F., Stevens, M., Militz, H. and Van Acker, J. (2002). Effect of process conditions on moisture content and decay resistance of hydro-thermally treated wood. Holforschung und Holzverwertung, 54(5), 94—96, 98-99. 

Culler, S.R., Ishida, H. and Koenig, J.L. (1986). The silane interphase of composites effects of process condition on y-aminopropyl triethoxysilane. Polym. Composites 7, 231-238. 

A study was made of the effects of processing conditions and of blowing and nucleating agents and external lubricants on the apparent density, mechanical properties, linear thermal expansion coefficient and surface roughness of extruded cellular MDPE. Based on the results, recommendations were formulated for the properties of cellular MDPE pipes for the protection of light conducting cables. 16 refs. (Translation of Polimery, Tworzywa Wielkoczasteczkowe, No. 10, 1996, p.580). 

In this paper, the type of information that can be obtained from the application of XANES to metal-containing systems is demonstrated. Examples are discussed from Y absorption edge studies undertaken to improve understanding of the mechanism of Y deactivation, the effects of processing conditions, and the chemistry of known Y passivators. Supplemental data were provided by bench unit evaluations of the Y-containing FCC catalysts. 

Shyu, S. L. and Hwang, L. S. (2001). Effects of processing conditions on the quality of vacuum fried apple chips. Food Res. Int. 34,133-142. 

The effects of processing conditions on refractories maybe summarized as follows (35) ... 

Consolidation/Fiber Motion Submodel The consolidation and fiber motion submodels evaluate the effects of processing conditions on the interaction between plies. In particular, the consolidation submodel (for thermoplastics) models the bonding between composite plies. The fiber motion submodel (for thermosets) yields the fiber position and fiber volume fraction within the cylinder. 

Mohamed, S. R. Debenedetti, P. G. Prud homme, R. K. Effects of Process Conditions on Crystals Obtained from Supercritical Mixtures. AIChE J. 1989b, 35, 325-328. 

Chongprasert S, Bottorff AT, Byrn SR, Williams NA, Nail SLThe effect of process conditions on crystallization of pentamidine isethionate during freeze drying. J Pharm Sci 1997 87 1155-1160. 

Jiang, S., Nail, S.L. Effect of process conditions on recovery of protein activity after freezing and freeze-drying. Eur. J. Pharm. Biopharm. 45, 249-257,1998... 

P. Holm, T. Schaefer, H.G. Kristensen, Granulation in high speed mixers. Part VI. Effects of process conditions on power consumption and granule growth, Powder Technol. 3 (1993) 286-293. 

Effect of processing conditions on fl-curve behaviour for in-situ Si3N4 composites.26... 

Herrera, M.L., Hartel, R.W. 2000a. Effect of processing conditions on crystallization kinetics of a milk fat model system. J. Am. Oil Chem. Soc. 77, 1177-1187. 

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