Polymer Engineering and Science · 1975 · 17 citations · 7 references
Natural SciencesMaterials EngineeringMaterials ScienceMechanical Behavior Of MaterialsPolymer EngineeringPolymer MaterialsInjection MoldingPolymer CharacterizationPolymer MorphologyPolymer PhysicsPolymer ProcessingThermoplastic PolymersInjection Molding TechniqueMold Temperature ControlMold Thermal BehaviorMolecular Weight DeterminationPhysical PropertiesPolypropyleneSpherulitesSpherulitic Morphology
Abstract The mechanical properties of a propylene‐ethylene copolymer resin depend strongly on the mold temperature employed during injection molding. Average spherulite size correlates well with most physical properties; good impact properties are related to small average size, and high heat distortion temperatures to large average size. Tensile specimens have three distinct regions when viewed through crossed polars. The outer region (Region 1) does not contain spherulites, but Regions 2 and 3 do. The largest spherulites are found in Region 3, the center of the specimen. Region 1 has a molecular weight higher than that of the other two regions.
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