Compatibilized low‐density polyethylene/linear low‐density polyethylene/nanoclay nanocomposites: II. Opposing effects of nanofiller on quiescent and shear‐induced crystallization

Abstract

Isothermal and non-isothermal crystallization processes of polyolefin nanocomposites based on low-density polyethylene/linear low-density polyethylene/nanoclay have been investigated, and the effects of nanoclay loading and dispersion state have been studied. Moreover, the isothermal crystallization of polyethylene chains has been evaluated in the quiescent and shear-induced conditions. In quiescent crystallization, adding 1 wt% nanofiller improves the crystallization rate, whereas an increment in the organoclay loading retards the crystallization process. However, an opposing effect of nanoparticles is observed in the shear-induced crystallization. The findings show that the incorporation of 5 wt% nanoclay in good dispersion state considerably accelerates the shear-induced crystallization process. This influence is found even for very weak shear flow fields. The synergistic effects of nanoclay addition and shear field presence on the crystallization process are of major significance particularly for polyolefin products, which are commonly manufactured by using melt processing methods. K E Y W O R D Sblend, crystallization, nanocomposite, polyethylene, shear

Characterization of linear low‐density polyethylene and halloysite nanotube (LLDPE/HNT) composites based on two‐roll calendering melt fabrication

“…In this discussion, the rate of crystallization was defined as the heat of the crystallization divided by the time for crystallization, that is, from onset to finish, and denoted by J g −1 s −1 . Retardation of nanocomposite crystallization at higher loading of nanoclay was reported by other researchers 51 …”

“…This reduction in polymer chain mobility reduces their ability to adopt a more crystalline structure and could reduce the size of crystallites 52,35 . These dual effects of HNTs on %crystallinity were also reported by other researchers when they add clay filler to PE 53,51 …”

“…52,35 These dual effects of HNTs on %crystallinity were also reported by other researchers when they add clay filler to PE. 53,51 The above observations indicate that there is neither an interactive effect of crosslinking nor degradation of the LLDPE molecules. The above observations also indicate that there is no chemical reactive interaction between the HNTs and LLDPE molecules.…”

“…Retardation of nanocomposite crystallization at higher loading of nanoclay was reported by other researchers. 51 The %crystallinity does not change much due to HNT incorporation, and this could attribute to the different effects of HNTs on LLDPE. HNTs could act as a nucleating agent and those that produced crystals increase the crystallinity of the nanocomposites.…”

Continuous extrusion foaming process of biodegradable nanocomposites based on poly(lactic acid)/carbonaceous nanoparticles with different geometric shapes: An insight into involved physical, chemical and rheological phenomena

“…It can be observed that with the incorporation of the carbonaceous nanoparticles, the storage and loss moduli as well as complex viscosity (, , and , respectively) experience a slight decrement, and the sample containing 0.25 phr GO has the nearest rheological behavior to the neat sample. By adsorbing the polymer chains on the solid surface of nanoparticles, it is expected that PLA molecules entropy decreases, and chain relaxation time, , of PLA chains enhances 42 . The mentioned influences can be studied with the investigation of the solid‐like behavior and of the polymer chains in melt 43 .…”