The microscopic observation of polymers and its composites
Przemysław Postawa, Józef Koszkul Politechnika Częstochowska, Katedra Przetwórstwa Tworzyw Sztucznych i Zarządzania Produkcją, al. Armii Krajowej 19c, 42-200 Częstochowa
Annals 4 No. 12, 2004 pages 451-454
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abstract Injection process seems to be simple on the surface, but it is, in reality extremely complex connection of several parameters. In a short time (several to twenty seconds) the state of the plastic which will influence its behaviour, its functional and strength features is frozen. One should therefore seek such solution, so that ensuring high quality of the product the smallest financial expenditure is possible i.e. select processing parameter in such a way, that energy consumption for a cycle should be as low as possible. Properties of injection molding parts, a specially accuracy dimensions and shape are depend on morphology of polymeric materials and processes running during cooling stage and crystallization. It is not possible to get a perfect morphology all over the injection molding part, because there are different conditions of crystallization and solidification of polymer in the other parts of molding during cooling stage. So we should use the optimal parameters of injection molding to get “better” morphology and mechanical properties of molded parts. Polyoxymethylene POM (SANITAL) M8 from group of partly crystalline polymers has been used for research. This is one of constructional materials commonly used in different types of precision mechanisms parts. It is characterized by large abrasion/high temperature resistance and low water absorbing capacity. The second one was polypropylene (MALEN P J-400) composite with 50% of glass fiber. Some of the new experimental optical technique of morphology investigations of polymers were presented in this paper. Results of morphology investigations using microscopic observation prove that mould temperature and cooling speed influences on propriety injection molded part and especially mechanical properties and dimensional accuracy. Using of high mold temperature and long time of cooling stage during injection molding can give better morphology and properties. Key words: polymer, processing conditions, morphology, crystallization