Homogeneous dispersion of multiwalled carbon nanotubes via in situ bubble stretching and synergistic cyclic volume stretching for conductive LDPE/MWCNTs nanocomposites

Abstract

Low-density polyethylene (LDPE)/multiwalled carbon nanotubes (MWCNTs) nanocomposites with different foaming agent (OBSH) contents were innovatively prepared via In Situ Bubble Stretching (ISBS) and synergistic cyclic volume stretching. The cyclic convergent and divergent flow makes the MWCNTs repeatedly subjected to bubble stretching, which is conducive to the efficient dispersion of MWCNTs in the matrix. The thermal weight loss of neat OBSH and nanocomposite were characterized by thermal gravimetric analyzer (TGA), which indicated that the OBSH in the nanocomposite had been completely decomposed into gas during the plasticizing transport process. The results of morphology showed that the moderate content of OBSH had better dispersion effect on MWCNTs. At optimal OBSH content, the OBSH could generate enough gas and larger bubbles per unit time to provide greater expansion forces to do much for the dispersion of MWCNTs. The dynamic mechanical analysis (DMA) was further carried out and also proved that the content of OSBH was an important factor for the dispersion of MWCNTs. Moreover, the relationship between the OBSH content and conductivity was discussed in details. The improvement in conductive properties of nanocomposites associated with the use of the method can be attributed to a more homogeneous dispersion of MWCNTs. POLYM. ENG.

Phase transformation and dielectric properties of polyvinylidene fluoride/organic‐montmorillonite nanocomposites fabricated under elongational flow field

“…Different from the traditional mixing equipment based on the shear flow field, such as, rotor mixer and twin‐screw extruder, the plasticization of polymer material in the vane mixer is dominated by the elongational flow field. The mechanical structure of vane mixer and its mechanism of generating strong elongational flow field have been explained in detail in our previous publications 27,30–33 . In short, as shown in Figure 1, the vane mixer is mainly composed of a feeding unit and a mixing unit.…”

Effect of in situ fibrillation on polyethylene/poly(ethylene terephthalate)/multiwalled carbon nanotube electromagnetic shielding foams

“…The application of microfoaming in electromagnetic shielding can reduce the weight of shielding materials and assist MWCNT to build a conductive network by the volume‐repulsion effect of microcells. [ 45,46 ] In this article, 0.5 wt% weight reduction is applied, we aim at using uniform cell size and distribution to maintain even distribution of MWCNT, thus promote high EMI SE with low filler content. [ 47 ]…”

In-Situ Bubble Stretching Assisted Melt Extrusion for the Preparation of HDPE/UHMWPE/CF Composites

“…Wu [31] proposed a method named in-situ bubble stretching to promote the dispersion of fillers in matrix and improve the composites' properties without modifying the structure of the mixing device. This method has been used to prepare polymer-based composites such as HDPE/Nano-CaCO 3 [31], GFO/pPI [32], LDPE/MWCNTs [33], HDPE/nano-SiC [34], which verified that in-situ bubble stretching (ISBS) is an efficient and environmentally friendly method to realize uniform dispersion of the fillers. Furthermore, the feasibility of the synergy of ISBS and extensional deformation was also confirmed according to the research by Yang [33] and Yin [34].…”