Correlation between isothermal crystallization and morphological/rheological properties of bimodal polyethylene/carbon black systems

Abstract

Studying factors that can cause changes in microstructure and different properties of polyethylene pipe materials are important to better predict pipe behavior. In this study, bimodal polyethylene compounds were prepared using three different grades of carbon black (CB) concentrated dispersion to investigate the role of CB carrier's molecular weight on microstructure, crystallization, and rheological properties of samples. Isothermal crystallization and Avrami equation showed the nucleating effect of CB and a decrease in overall crystallinity caused by CB particles, with no major effect of carrier molecular weight on polyethylene unit cell parameters, confirmed with WAXD measurements. Similarly, it was revealed by FE‐SEM images that the higher the molecular weight of CB carrier, the lower the compound's ability to form three‐dimensional spherulites. The melt miscibility of samples was evaluated based on rheological properties, while a correlation between rheological parameters and Avrami index was observed. It is concluded that a small amount of CB carrier can change the balanced molecular weight distribution of bimodal polyethylene resin and strongly influence crystallization behavior and microstructure development of samples. The microstructure of bimodal black polyethylene compounds can determine their properties, especially long‐term performance like resistance to slow crack growth.

Isothermal crystallization kinetics of pure and surface‐modified silica/high‐density polyethylene nanocomposites

“…This is also consistent with the trend of the crystal growth rate ( G ) at different T c 48,49 . The mentioned phenomenon can affect the crystalline morphology, and therefore the physical and mechanical properties of polymers change with T c 50 …”

“…48,49 The mentioned phenomenon can affect the crystalline morphology, and therefore the physical and mechanical properties of polymers change with T c . 50 Tobin's model was the other theoretical strategy used to investigate the isothermal crystallization kinetics in HDPE pure and nanocomposite samples. Generally, the model is the developed form of Avrami's equation which also considers the latter stage of the isothermal crystallization 51,52 :…”

Konduktivitas Listrik Poly(Lactic Acid) dengan Variasi Bahan Isian Karbon: Review

“…Konsentrasi CB dalam proses dispersi akan berbeda-beda menurut polimer pembawanya dengan perbedaan berat molekul, perbedaan metode dan penambahan aditif. Oleh karena itu akan terjadi perbedaan efek pada struktur mikro, rheology, mekanik, dan daya tahan komponen CB [13]. Konduktivitas elektrik karbon tergantung pada proses produksi yang dijalankan, terutama pada area permukaan dan struktur dari CB yang dipengaruhi oleh proses.…”

Effect of blend composition on the adhesion strength of EVA‐g‐MA/LLDPE‐g‐MA films to epoxy substrates

“…30 The addition of a second phase can remarkably alter the crystallinity of polymers by promoting or inhibiting the crystallization, 20 depending on their properties and the processing conditions. [31][32][33][34][35] For instance, in some cases, the crystals of one phase can act as nucleation regions for the second phase and facilitate the crystallization process. 36,37 On the other hand, the second phase can also interfere with the crystallization of the polymer blend by reducing the chain mobility and delaying chain alignment and crystallization phenomenon.…”