Fracture behavior of bimodal polyethylene: Effect of molecular weight distribution characteristics

Polyethylene loss of ductility during oxidation: Effect of initial molar mass distribution

“…-On the other hand, PDI values of low dispersed samples (PE 2,7 , PE 3,4 ) slightly increase, probably due to crosslinking (as it will be discussed later) and reach a plateau value close to 4.…”

“…In order to reach higher mechanical properties for specific applications, PE with high molecular weight had been commercialized [7,8]. The main drawback of high molecular weight PE's is their high melt viscosity which limits their processability.…”

Correlation between rheological and mechanical properties of black PE100 compounds – Effect of carbon black masterbatch

“…This can be indicative that folding of higher molecular weight chains in crystalline lamellas is facilitated because of existing lubricants and lower molecular weight chains in MK masterbatch. Sun et al [11] and Wu et al [4] showed that the number of thicker lamellas can be increased by increasing lower molecular weight fraction in bimodal PE materials while total crystallinity remains the same, which explains higher average lamellar thickness in PE100-MK. On the other hand, this facilitated chain folding of high molecular weight molecules in thick lamellas can lead to lower number of long chains tie-molecules in amorphous region and subsequently decreased chain entanglements in interlamellar areas, effectively obstructing demonstration of strain hardening as it is believed that strain hardening is directly correlated with density of chain entanglements [37].…”

“…It has also been shown that the stereoregularity of the copolymer fraction of bimodal high-density polyethylene influences the environmental stress crack resistance [10]. Sun et al [11] studied effect of molecular weight distribution on fracture behavior of bimodal PE materials and demonstrated that with increasing ratio of lower M w fraction to higher M w fraction, fracture toughness improves and also, the amount of thicker lamellas in structure increases without much change in total crystallinity of samples. Studies have shown that long term exposure to UV radiation can negatively affect mechanical properties, alter polymer structure and initiate cracks in polyethylene structures [12][13][14].…”

Exceptional free radical polymerization and block copolymerization of captodative substituted methyl 2-methoxyacrylate

“…[10] While, cluster polymers including bimodal MW distribution polymer and block copolymer have been interested as the materials with both higher and lower MW polymer characteristics and unique bifunctionality. [12][13][14] For instance, higher MW polymer has higher strength but is difficult to process. Contrary, lower MW polymer is endued with good toughness and rheological properties but lower rigidity.…”