Melt flow index of low-density polyethylene determination based on molecular weight and branching properties

Abstract

Industrially, a low-density polyethylene (LDPE) is characterized based on their Melt Flow Index (MFI). In numerous publication, LDPE’s MFI is correlated to its average molecular weight (Mw). An overview of modeling studies on LDPE reactors available in the open literature indicates significant discrepancies among researchers for the correlation of MFI-Mw, therefore a research to produce reliable correlation need to be carried out. This research gathers various experimental and industrial data of different LDPE product grades. Empirical correlations between MFI and Mw are developed and the analysis on the MFI and Mw relation is addressed. The percentage of error between the model prediction and industrial data varies from 0.1% to 2.4% which can be considered minimum. The nonlinear model obtained indicates the competency of the developed equation to describe the variation of industrial data, thus allowing greater confidence in LDPE’s MFI prediction.

Dynamic optimization of low-density polyethylene production in tubular reactor under thermal safety constraint

“…The energy balance for the reaction and cooling zones are represented by Equations (19) and (20), respectively [7].…”

“…Equations (37) -(39) represent the calculations for monomer conversion (XM), weightaverage molecular weight (MW) [8] and melt flow index (MFI) [20].…”

“…The melt flow index (MFI) is the parameter which is commonly practiced in global LDPE manufacturing industry. It acts as an indicator of the molecular weight (Mw) and is favoured over other parameters because of its rapid and simple determination [20].The results shown in Table 2 are the optimum reactor output achieved with optimal parameter values and trajectory of TJ as shown in Table 3 and Figure 6, respectively. The resulting optimization profiles of XM, T, and Tc are shown in Figures 7 -9, respectively.…”

“…The robustness quality of LDPE's property leads to various usage of such polymer which considers as an exclusive and high demand commodity [1,2]. The production and consumption rates of LDPE are reported to be 20.31 million tons in 2015 [3]. The market study reveals that the projection of LDPE consumption and production rates would continue to increase steadily, which justifies its continuous improvement for the past 40 years [4,5].…”

Controlling Morphological Development during Additive Manufacturing: A Route to the Mapping of Properties

“…The material used was Respol LDPE, Alcudia 1970C, with a melt flow index of 7.5 g/10 mins equating to a molecular weight of ~7 × 10 4 Daltons. [3]. Differential scanning calorimetry measurements showed that the onset of crystallization in LDPE happens at 94.2 • C with a maximum rate of crystallization observed at 90.2 • C. These measurements relate to the quiescent melt and the values may be modified by the flow processes inherent in extrusion.…”