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Co-rotating Twin Screw Extruder (co-rotating + twin_screw_extruder)

Distribution by Scientific Domains

Polymers and Materials Science	87%

Selected Abstracts

Mapping approach for 3D laminar mixing simulations: application to industrial flows

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3-4 2002
O. S. Galaktionov
Abstract The computationally efficient mapping technique is applied to model laminar mixing in the transport section of the co-rotating twin screw extruder. The technique uses coarse grain values to describe the mixture and exploits temporal and spatial periodicity of the flow. The mapping approach yields adequate description of the concentration fields and residence time distributions. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Simulations of grafting monomers and associated degradation of polypropylene in a modular co-rotating twin screw extruder

JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2005
Jongmin Keum
Kinetic models of grafting maleic anhydride (MAH) and methyl methacrylate (MMA) on polypropylene (PP) were developed for screw extrusion. However, the kinetic models were insufficient to explain the grafting reactions along the length of modular co-rotating twin screw extruders because the rheological properties and the residence time of PP changed owing to degradation of PP during the grafting reaction. In order to model this system for a modular co-rotating twin screw extruder, the kinetic model of grafting reaction and models for degradation of PP were combined with fluid mechanics and heat transfer. Given the geometrical configurations of the screw, the operating conditions, and the physical properties of the polypropylene, the simulations predicted variation of molecular weight and mean residence time due to degradation of PP. The weight percent of grafted MAH or MMA on PP profiles along the screw axis was also calculated in the simulation. These predictions were compared with experimental data for various operating conditions. J. VINYL. ADDIT. TECHNOL. 11:143,149, 2005. © 2005 Society of Plastics Engineers. [source]

Preparation of poly(lactic acid)/poly(ethylene glycol)/organoclay nanocomposites by melt compounding

POLYMER COMPOSITES, Issue 3 2006
Shuichi Tanoue
Poly(lactic acid) (PLA)/organoclay nanocomposites were prepared by melt compounding in a co-rotating twin screw extruder. Two types of commercialized organoclay (dimethyl benzyl stearyl ammonium ion and dimethyl distearyl ammonium ion intercalated between clay platelets named as Clay A and Clay B, respectively) and two grades of poly(ethylene glycol) (PEG) with different molecular weight (Mw = 2,000 and 300,000,500,000 named as PEG2k and PEG500k, respectively) were used in this study. The Young's modulus improved by the addition of organoclay to PLA matrix. The Young's modulus decreased with the addition of PEG to PLA/organoclay nanocomposites. The tensile strength and elongation of PLA/Clay B nanocomposites increased with the addition of PEG2k. The effect of the addition of PEG on d -spacing of PLA/organoclay nanocomposites is dependent upon the kind of organoclay. The sizes of clay agglomerations in PLA/PEG/organoclay nanocomposites are larger than those of PLA/organoclay ones in the same organoclay. Addition of PEG to PLA/organoclay nanocomposites during melt compounding will not be useful for the preparation of PLA/organoclay having fully exfoliated clay platelets. The shear thinning properties of the nanocomposites are independent of the addition of PEG. On the whole, PEG2k is good plasticizer for PLA/organoclay nanocomposites. POLYM. COMPOS. 27:256,263, 2006. © 2006 Society of Plastics Engineers [source]

Local residence time, residence revolution, and residence volume distributions in twin-screw extruders

POLYMER ENGINEERING & SCIENCE, Issue 1 2008
Xian-Ming Zhang
This work was aimed at studying the overall, partial, and local residence time distributions (RTD); overall, partial and local residence revolution distributions (RRD) and overall, partial and local residence volume distributions (RVD) in a co-rotating twin screw extruder, on the one hand; and establishing the relationships among them, on the other hand. Emphasis was placed on the effects of the type and geometry of mixing elements (a gear block and various types of kneading elements differing in staggering angle) and process parameters on the RTD, RRD and RVD. The overall and partial RTD were directly measured in-line during the extrusion process and the local ones were calculated by deconvolution based on a statistical theory. The local RTD allowed comparing the mixing performance of mixing elements. Also it was confirmed both experimentally and theoretically that specific throughput, defined as a ratio of throughput (Q) over screw speed (N), controlled all the above three types of residence distributions, be they local, partial or overall. The RRD and RVD do not provide more information on an extrusion process than the corresponding RTD. Rather they are different ways of representing the same phenomena. POLYM. ENG. SCI., 48:19,28, 2008. © 2007 Society of Plastics Engineers [source]

Amphiphilic block copolymers of PtBA- b -PMMA as compatibilizers for blends of PET and PMMA

POLYMER ENGINEERING & SCIENCE, Issue 9 2006
B. Dewangan
PET and PMMA were blended at various weight fractions. These blends were compatibilized by employing amphiphilic block copolymers of PtBA- b -PMMA, having three compositions (1:3, 1:1, 3:1) and three weight fractions (3, 5, and 7 wt%) using a co-rotating twin screw extruder. The blends were evaluated for their mechanical, rheological, and morphological properties. Overall, the compatiblized blends showed improvement in properties compared with the properties of noncompatiblized blends. Mechanical properties of the compatibilized blends improved with an increase in the PMMA and compatibilizer weight fractions. It was observed that the compatibilizer with lower molecular weight and lower glass transition temperature, typically at 5 wt%, provided the overall best properties. POLYM. ENG. SCI. 46:1147,1152, 2006. © 2006 Society of Plastics Engineers. [source]

Experimental investigation of the energy balance for the metering zone of a twin screw extruder

POLYMER ENGINEERING & SCIENCE, Issue 2 2000
Stephan Tenge
The object of this study is to investigate experimentally the mechanical power transported from the screws to the polymer melt, the heat dissipated in the polymer melt, and the heat transferred to the barrel of the metering zone of a co-rotating twin screw extruder. For the experimental investigations, different screw elements, mixing elements, and kneading discs are used. The experimental results for the dissipation show good agreement with known calculation models. For the calculation of the heat transfer, a new equation is used to calculate the mean temperature difference under consideration of the dissipation. The Nusselt-number can be calculated in good agreement with the experimental results as a function of the Brinkmann-number. [source]