Process for Producing High Melt Flow Polymers (original) (raw)
Polyethylene Processing, 2018
A reaction in which polymer chain is formed by combining large number of small molecules called "Monomers". • Polymerization reaction steps:
Role of processing aids in the extrusion of molten polymers
Journal of Vinyl and Additive Technology, 2002
Columbia 221 6 Main Mall Vancouuer, BC 6VT 124, Canadu Froduct quality and, in general, processing windows and rates of production in the extrusion of molten polymm are limited by various flow instabilities (mainly melt fi-acture) that are observed at high production rates. While there still are unresolved issues in comprehending these phenomena, industry demands for process optimization dictate the employment of processing aids (PAS) for product quality improvement and energy requirement reduction. In this review paper, most commercially used processing aids (PAS) are discussed, namely, fluoroelastomers. stearates, small amounts of polymers blended with the process polymer, and the newly discovered boron nitxide as pure and in combination with other fluoroelastomers. This paper focuses on the appropriate and optimum usage of the various PAS as well as on the mechanism that underlies their action for flow enhancement and instability elimination. Finally, numerous experimental observations are discussed, and several examples are illustrated. PAS on the rheologid properties and the instability (melt fracture] elimination is also discussed. The factors that determine the additive performance, such as concentration, dispersion quality. and interactions between additives, additive and polymer, and additive and die surface, are also examined. The various mechanisms by which Merent types of processing aids help eliminate the instabilities are reviewed as well. Section 2 discusses the various melt fi-acture phenomena in 'Dafieated tothe lnemoryof Dr. Charles w. Stewart, an imnstlgator* made *Author rrsponsiMe for conrspdmce. emaIk h a t z i k J & h~. u b c. c a 8orrTBl CXCCPUOIld eonttibutblU3 the-Of alds.
Effects on Product Part During Changing the Processing Parameters of Polypropylene Material
Journal of Harmonized Research in Applied Science
Introduction: Injection molding is considered one of the most communal plastic part manufacturing processes. Used for producing quantities from both thermoplastic and thermo-set polymers. The process commonly initiates with taking the polymers in the form of pellets or granules and heating them to the molten state [2]. The melt is then injected into a chamber formed by a split-die mold. The melt remains in the mold and is either chilled down to solidify or heated up to cure (thermo-sets). The mold is then opened and the part is ejected [3]. Instead of the relatively expensive tooling cost, injection molding remains the most popular manufacturing process for plastic materials in mass production, it has low operational cost, high throughput, and flexible to make parts with complex shapes.