Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 11, 2009) Thesis advisor: Fu-Hung Hsieh. Includes bibliographical references.

Thesis (M.S.)--Ohio University, March, 1989. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, June, 1996. / Title from PDF t.p.

Physical properties and morphology of extruded semicrystalline polymers can be significantly affected by modification and change in die design and melt viscosity of the molten polymer. Further modifications to physical properties (i.e. density and open cell fraction) of foamed material occur, following the modification of melt viscosity by melt blending of polypropylene and high density polyethylene). The main object of this research project was to carry out a systematic examination of rheological properties of polymer/gas mixture, affect of die design, polymer molecular weight (melt viscosity), and processing conditions on density, open cell fraction, cell morphology (i.e. cell size and cell size distribution) and micromorphology of polyolefin foams. Also attention was given to method of stabilisation of extruded foam, where, it was found support of the extrudated foam (by adding a specially designed die adapter to the end of the die) prior to entering the cooling tank could result not only to a specimen with uniform cross section, but also due to drop in melt temperature, the cell walls are to some extent rigidized, hence, the collapse of bubbles are limited. From commercial point of view control of cell collapse, density and open cell fraction, will make these foamed materials valuable for their filtration characteristics. Microstructural analysis of polypropylene (unfoamed state) by X-ray diffraction and Differential Scanning Calorimetry revealed 13-spherulites are only formed in skin layer, and beneath the thickness of 500 pm from the surface, the crystal structure of this polymer is only consist of B-spherulites. On the other hand, the chemical blowing agent (Hydrocerol CF-20), was found to have nucleating affect on microstructure of polypropylene, where, it has resulted in reduction of size of spherulites together with a drop in recrystallisation temperature and formation of P and a spherulites through the thickness of extrudated foam. The foregoing chemical blowing agent was found to have no significant affect on the crystal structure of the high density polyethylene.

[pt] O principal objetivo deste trabalho foi avaliar de forma quantitativa a aplicação da fotoplasticidade como técnica experimental, na predição das grandes deformações plásticas que ocorrem em componentes metálicos, quando são trabalhados em processos de conformação mecânica. Esta avaliação foi feita através do estudo do problema de extrusão plana. As distribuições das deformações obtidas através da analise fotoplastica foram comparadas com as obtidas técnica de malha, em modelos planos feitos de resinas poliéster e epóxi, chumbo e alumínio. Na procura de determinar o polímero que melhor reproduz o comportamento mecânico dos outros materiais comumente empregados em processos de conformação, várias combinações de resinas poliéster rígida e flexível, e uma nova formulação de resinas poliéster rígida e flexível, e uma formulação de resina epóxi ainda em desenvolvimento, foram estudadas quando submetidas a extrusão plana. Os resultados foram comparados com os obtidos para modelos de alumínio e chumbo, submetido ao mesmo processo de conformação mecânica. Embora outras misturas de resina poliéster tenham tido resultados satisfatórios, verificou-se, que a mistura 70 por cento rígida e 30 por cento flexível modela bem as deformações plásticas que ocorrem na extrusão de materiais como chumbo e alumínio, se fatores de correção adequados forem utilizados. / [en] The main objetive of this thesis is to evalute in a quantitative manner the possibility of employing photoplasticity as na experimental techinique for the predection of large plastic strains which occur in mechamnical forming. This was made throught an experimental study of the plane extrusion problem. Distribuitions of strains obtained through the photoplastic analystic were compared to those obtained by the grid technique in plane models made of spoxy and polyester resinds, lead and aluminum. Trying to determine the polymer that best reproduces the mechanical behavior of other materials commonly used in forming processes, several combinations of rigid and flexible polyester resins and a new formulation of a epoxy resin still in development ere studied when submitted to plane extrusion. The results were compared with those obtained from aluminum and lead models subject to the same mechanical process. Although, other combinations of polyester resind present satisfactory results, it was verifyed that the combination of 70 per cent rigid and 30 per cent flexible polyester resins was teh one that best modeled the plastic strains that occurred in the plane extrusion of the aluminum and lead specimens, if appropriate correction factors were aplled to take into account the plastic strain recovery which occurs right after unloading of the polyester specimens.

L’extrusion assistée eau est un procédé basé sur l’extrusion classique réactive. La particularité de ce procédé est la mise en place d’une pompe d’injection d’eau au niveau de la zone de compression de l’extrudeuse. Ce principe a déjà fait ses preuves dans la formulation de nanocomposites le plus souvent à matrice polyamide et à base de nanocharges d’argile. L’eau joue le rôle d’exfoliant permettant ainsi une meilleure dispersion de l’argile au sein de la matrice. Un second rôle a été observé, l’eau jouerait le rôle de plastifiant durant l’extrusion et permettrai de limiter la dégradation du matériau. Ce procédé a donc été étudié avec deux profils de vis différents afin d’utiliser les inconvénients du premier pour créer un deuxième profil adéquat à l’utilisation de l’eau. Le polyamide 6 a été utilisé comme matériau de référence afin de sélectionner de nouveaux polymères biodégradables. Deux polyesters, le polybutylène succinate (PBS) et le polybutylène succinate adipate (PBSA) ont montrés des aptitudes similaires au PA6 pour l’utilisation de l’eau. Après extrusion des polymères avec injection d’eau, une limitation de la diminution des masses molaires a pu être observée. Les propriétés mécaniques et rhéologiques du PA6 ont été améliorées. Par la suite, une application de ce procédé a été menée sur la formulation d’un composite à matrice PBS à base de deux types de nanocharges d’argiles afin d’améliorer les propriétés mécaniques du PBS et d’évaluer l’influence de l’eau selon l’argile utilisée. / Water-assisted extrusion is a method based on the conventional reactive extrusion. The feature of this method is the introduction of a water injection pump at the compression zone of the extruder machine. This process has already been proven in the nanocomposite formulation, usually based on polyamide (PA) matrix with clay nanofillers. The water acts as exfoliating thus allowing better dispersion of the clay within the matrix. A second role was observed, water would act as a plasticizer during extrusion limiting the material. In this context, water-assisted extrusion was studied using two different profile screw, where the second profile is an optimisation from the first. Polyamide 6 (PA6) was used as material reference in order to select new biodegradable polymers. Two polyesters, poly(butylene succinate) (PBS) and poly(butylene succinate adipate) (PBSA) have shown similar abilities comparared with PA6 extruded under water. After extrusion of the polymers with water injection, a limitation on the decrease in molecular weight was observed. Mechanical and rheological properties of PA6 were improved. Subsequently, an application of this method was conducted on the formulation of a PBS matrix composite based on two types of nanofillers clay in order to improve the mechanical properties of PBS and evaluate the water influence during the extrusion process according to the clay used.

Bioplastics produced from agricultural resources are gaining attraction in recent years because of their sustainability and potential biodegradability. Wheat gluten (a wheat protein) is among the potential feedstocks, which stands out because of its availability, low price, good biodegradability, and good viscoelastic properties. This paper provides state-of-art information on the processing of wheat-based bioplastics with their potential applications. It gives an overview of the structure of wheat gluten, its manufacturing processes (casting, thermoforming, extrusion, compression molding, injection molding), thermal-mechanical properties (tensile strength, elongation at break, young?s modulus, water vapor pressure, gas permeability, etc.) of processed plastic films and rigid products, methods to improve the properties, potential applications (packaging, biomedical, adhesives, cosmetics), and limitations and prospects of wheat-based bioplastics.

No description available.

No description available.

Yes / Herein, the benefits which extrusion can provide for the automated continuous synthesis of organic compounds are highlighted. Extrusion is a well-established technique that has a vital role in the manufacturing processes of polymers, pharmaceuticals and food products. Furthermore, this technique has recently been applied to the solvent-free continuous synthesis of co-crystals and coordination compounds including metal-organic frameworks (MOFs). To date, a vast amount of research has already been conducted into reactive extrusion (REX), particularly in the polymer industry, which in many cases has involved organic transformations, however, it has not received significant recognition for this. This review highlights these transformations and discusses how this previous research can be applied to the future of organic compound manufacture. / EPSRC (EP/L019655/1)