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Reactive Extrusion Process (reactive + extrusion_process)

Distribution by Scientific Domains

Polymers and Materials Science	100%

Selected Abstracts

Study of Polyurethane Formulations Containing Diols Obtained via Glycolysis of Poly(ethylene terephthalate) (PET) by Oligoesters Diols through a Reactive Extrusion Process

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2005
Gaël Colomines
Abstract Summary: The glycolysis of PET by oligoester diols in the presence of zinc acetate was carried out in two successive twin-screw extruders with total residence times of 4 min and without solvent. These new glycolysates were analyzed and used in polyurethane formulation with a commercial polyol. The reactivity of these formulations was studied. The mechanical properties, thermal and swelling behavior of these polyurethanes were investigated. Mechanical properties are improved with the addition of glycolysate. The thermal behavior is not modified with the addition of glycolysate. The swelling behavior of the material depends on the solvent nature. The addition of glycolysate allows a decrease in material swelling in chloroform but increases this swelling in acetone. [source]

A Solvent Free Graft Copolymerization of Maleic Anhydride onto Cellulose Acetate Butyrate Bioplastic by Reactive Extrusion

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 1 2006
Arief C. Wibowo
Abstract Summary: Interfacial adhesion between fibers and matrix is a crucial factor for effective stress transfer from matrix to fiber; especially in short fiber reinforced composite systems. The use of a chemical compatibilizer is an efficient means to achieve such adhesion. Maleic anhydride-grafted-cellulose acetate butyrate (CAB-g-MA) is one such compatibilizer which can be used in biocomposite fabrication, and this has been synthesized in our laboratory by utilizing a twin-screw reactive extrusion process in the presence of a free radical initiator (2,5-dimethyl-2,5-di(tert -butylperoxy)hexane). The unique feature of this process is its solvent-free approach for grafting of maleic anhydride onto CAB, without hydroxyl group protection. CAB-g-MA was characterized using FTIR as well as by a non-aqueous titration method. The effects of initiator and monomer concentrations and various processing conditions on the graft content were also investigated. The preliminary results show that by adding approximately 10 wt.-% of CAB-g-MA into a plasticized cellulose acetate butyrate (TEB)-industrial hemp fiber biocomposites system, an improvement in tensile strength (20%) and in tensile modulus (45%) were obtained. These results are promising in that they pave the way for future studies involving the use of CAB-g-MA as a suitable compatibilizer for cellulose ester-natural fiber biocomposites. [source]

On Toughness and Stiffness of Poly(butylene terephthalate) with Epoxide-Containing Elastomer by Reactive Extrusion

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 8 2004
Zhong-Zhen Yu
Abstract Summary: To obtain a balance between toughness (as measured by notched impact strength) and elastic stiffness of poly(butylene terephthalate) (PBT), a small amount of tetra-functional epoxy monomer was incorporated into PBT/[ethylene/methyl acrylate/glycidyl methacrylate terpolymer (E-MA-GMA)] blends during the reactive extrusion process. The effectiveness of toughening by E-MA-GMA and the effect of the epoxy monomer were investigated. It was found that E-MA-GMA was finely dispersed in PBT matrix, whose toughness was significantly enhanced, but the stiffness decreased linearly, with increasing E-MA-GMA content. Addition of 0.2 phr epoxy monomer was noted to further improve the dispersion of E-MA-GMA particles by increasing the viscosity of the PBT matrix. While use of epoxy monomer had little influence on the notched impact strength of the blends, there was a distinct increase in the elastic stiffness. SEM micrographs of impact-fracture surfaces indicated that extensive matrix shear yielding was the main impact energy dissipation mechanism in both types of blends, with or without epoxy monomer, and containing 20 wt.-% or more elastomer. SEM micrographs of freeze-fractured surfaces of PBT/E-MA-GMA blend illustrating the finer dispersion of E-MA-GMA in the presence of epoxy monomer. [source]

Analysis of chemical calorific effect during reactive extrusion processes for free radical polymerization

POLYMER INTERNATIONAL, Issue 12 2007
Yuxi Jia
Abstract In the reactive extrusion process for polymerization, the chemical calorific effect has a great influence on the temperature. In order to quantitatively analyze the polymerization trend and optimize the processing conditions, the phenomena of the chemical calorific effect during reactive extrusion processes for free radical polymerization were analyzed. Numerical computation expressions of the heat of chemical reaction and the reactive calorific intensity were deduced, and then a numerical simulation of the reactive extrusion process for the polymerization of n -butyl methacrylate was carried out. The evolutions of the heat of chemical reaction and the reactive calorific intensity along the axial direction of the extruder are presented, on the basis of which reactive processing conditions can be optimized. Copyright © 2007 Society of Chemical Industry [source]