Temperature window effect and its application in extrusion of ultrahigh molecular weight polyethylene

Fang, Liming; Gao, Ping; Cao, Xian Wu

doi:10.3144/expresspolymlett.2011.66

Cited by 12 publications

(6 citation statements)

References 31 publications

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“…The in situ wide angle X‐ray diffraction studies on HDPE have confirmed the hypothesis by the observation of the transformation from an orthorhombic phase to a hexagonal phase through . Besides, the temperature window effect of ultrahigh‐molecular‐weight polyethylene in its ram extrusion was studied by Fang et al . The results showed that the stable extrusion pressure and the critical piston velocity decrease with the rise in the extrusion temperature, and the temperature window increases with molecular weight of polyethylene.…”

Section: Introductionmentioning

confidence: 75%

Structure memory effects of polyethylene blends in temperature window

et al. 2013

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Temperature window effect has been used to extrude polyethylene blends 5000s/TR‐571 and bimodal polyethylene GC100s with low extrusion temperatures and pressures. Rheological results indicate that the temperature window effect occurs during the extrusions of the GC100s and blends 5000s/TR‐571. For the blends 5000s/TR‐571, both the temperature window and the minimum extrusion pressure dramatically decreases with increasing content of 5000s. For bimodal polyethylene GC100s, successive self‐nucleation and annealing (SSA) fractionation results suggest that the pick at high temperature on the SSA curve of the extrudates obtained inside the temperature window is remarkably lower than those of the extrudates obtained outside the temperature window. This indicates that the lamellae of the extrudates obtained in the window are thinner than those obtained outside the window, which is attributed to the fact that the well‐aligned chains as the result of structure memory effect can act as nucleating agent in the crystallization process. POLYM. ENG. SCI., 54:303–309, 2014. © 2013 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 75%

Structure memory effects of polyethylene blends in temperature window

et al. 2013

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“…Therefore, the UHMWPE melt was easy to break up by strong shear effect with internal mixer. Although there exists a metastability processing window in the temperature range of 154°C and 157°C [27][28][29], the nascent UHMWPE cannot be processed by conventional or improved upgrade screw equipment without processing aids. Considered the complicated interfering factors of extremely high melt viscosity, low melt flow rate, low critical shear rate no viscous flow and so on, it is a huge challenge to process UHMWPE continuously and efficiently via screw equipment dominated by shear flow and methods based on viscous flow theory.…”

Section: Extrusion Of Metals Polymers and Food Productsmentioning

confidence: 99%

Extrusion Processing of Ultra-High Molecular Weight Polyethylene

Zhang¹,

Liang²

2018

Extrusion of Metals, Polymers and Food Products

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Ultra-high molecular weight polyethylene (UHMWPE) is a unique thermoplastic polymer with excellent performances. It has ultra-high molecular weight and extreme rheological behaviour, which make it a worldwide challenge to process UHMWPE continuously with little or without processing aids. Although the polymer processing technology has been increasingly maturated, it still cannot carry out the industrialized production efficiency by conventional processing methods and apparatus at present. In this chapter, we review the progress of extrusion processing technology for UHMWPE, including ram extrusion, single screw extrusion, twin screw extrusion and novel extrusion technology based on extensional rheology. By summarizing of these processing technologies, a basic framework of the processing principles and methods for UHMWPE is clearly presented. It is helpful for us to understand the processing characteristics and methods for such thermoplastic polymer with ultra-high molecular weight.

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“…However, like 1,2,4-tricholorobenzene, this is also toxic to the aquatic environment (with −log(LC 50,FM ) = 4.8), besides being highly volatile. Apart from decalin, aromatic compounds like naphthalene 57 and p-xylene 58 are the other solvents currently used in this process but do not have satisfactory EH&S properties.…”

Section: ■ Introductionmentioning

confidence: 99%

Systematic Model-Based Methodology for Substitution of Hazardous Chemicals

Jhamb

Gani

Kontogeorgis

2019

ACS Sustainable Chem. Eng.

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Driven by obligations to comply with the regulations and various public policies, substitution of chemicals with safer counterparts is now being widely practiced by industry. In this paper, the development of a systematic model-based methodology for chemical substitution, is described. The methodology considers different problem definitions depending on the objective for substitution. A general framework, which includes the algorithm steps of the methodology, corresponding data-flow, associated property models, databases and modeling tools for generating and evaluating the substitute candidates, is presented. The application of the developed methodology is highlighted through four case studies on substitution of 'chemicals of concern' used in chemical-based products or in processes and their operation. The alternative chemicals are found by matching the desired properties related to the physicochemical nature, function and performance of the chemical being substituted, while avoiding its undesired, environmental, health and safety-related properties.The objective of developing this methodology for chemical substitution is to quickly and reliably identify the promising candidates through model-based techniques, check their economic feasibility and only then proceed to conduct experiments in order to verify their compatibility and applicability.In this way, the experimental resources are used only for verification rather than for an inefficient, trial-and-error and sometimes time-consuming and expensive search for substitute candidates.

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Temperature window effect and its application in extrusion of ultrahigh molecular weight polyethylene

Cited by 12 publications

References 31 publications

Structure memory effects of polyethylene blends in temperature window

Structure memory effects of polyethylene blends in temperature window

Extrusion Processing of Ultra-High Molecular Weight Polyethylene

Systematic Model-Based Methodology for Substitution of Hazardous Chemicals

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