Polypropylene‐based in situ fibrillation‐reinforced ternary composite foams with improved filler‐phase dispersion

Abstract

Recently, the issue of energy-saving and environmental protection has attracted enormous interest in developing polymeric composite foams. Fillers have been identified as major materials to tailor cellular structures and mechanical properties for single component thermoplastics. However, it is often difficult to achieve the desired effect due to the natural tendency of fillers. The study aims to provide a facile method for improving the dispersion and arrangement of filler phase based on in situ fibrillation. Polytetrafluoroethylene (PTFE) was used in the in situ fibrillated phase to promote the dispersion of talc throughout the polypropylene (PP) matrix for the ternary composite foams of PP/talc/PTFE. The mechanisms of PTFE fibrils and their effect were studied in terms of crystallization, rheology, foaming behavior, and mechanical properties. The results proved that a fibrillar network was formed

Preparation of lightweight and high‐strength polypropylene‐based ternary conductive polymer foams by in situ microfiber reinforcement

“…The melt heat absorption peaks of the PP/MWCNTs binary composite and the PP/MWCNTs/PTFE multicomposite also moved to higher temperatures after the second melt heat absorption process, which may be related to some crystal structures becoming more perfect. 16,18 Table 4 summarizes the key parameters of nonisothermal thermal crystallinity of the component materials. It was found that for the PC1 and PC2 groups, the crystallinity decreased with the addition of MWCNTs over pure PP.…”

“…As a result of the difficulty of dispersing MWCNTs within the matrix, and even though MWCNTs have heterogeneous nucleation, PP molecular chains are restricted in mobility as a consequence of agglomeration, which hampers the crystal growth process by reducing the ability of PP molecules to reach the crystallization site. 16,18 In addition, after the addition of PTFE to the in situ fiber-forming reinforced ternary composite system, both the heat absorption peak, the exothermic peak temperature, and the crystallinity were further enhanced compared with pure PP and pure PP/MWCNTs binary composites. In addition to promoting heterogeneous nucleation and providing more crystallization points for the matrix, well-distributed PTFE microfibers also improved the dispersion characteristics of MWCNTs by PTFE microfibers and thus resulted in a higher crystallinity for the PC2F3 group with higher MWCNTs content at the same PTFE concentration.…”

“…14,15 Most previous studies have focused on in situ fibrillation-based method for obtaining fibrils with high aspect ratios, which is increasingly recognized as an effective method to improve melt strength, rheology properties, and foaming behavior. [16][17][18][19] Furthermore, the presence of fibrillar networks is related to the role of heterogeneous nucleation agents in refining crystals. Jiang et al 20 introduced polytetrafluoroethylene (PTFE) fibrils into the prepared microporous polyethylene terephthalate (PET), which improved the crystallization temperature, crystallization rate, as well as the viscoelastic behavior of PET.…”

“…Most previous studies have focused on in situ fibrillation‐based method for obtaining fibrils with high aspect ratios, which is increasingly recognized as an effective method to improve melt strength, rheology properties, and foaming behavior 16–19 . Furthermore, the presence of fibrillar networks is related to the role of heterogeneous nucleation agents in refining crystals.…”

Study on preparation of highly dispersed graphite composite expandable polystyrene foam by homogeneous dissolution‐suspension polymerization with waste polystyrene

“…[12] Rajeev dissolves expanded polystyrene in tetrahydrofuran and converts wEPS into polystyrene nanoparticles by nanoprecipitation. [13] Miao proposed EPS screw extrusion pelletizing technology, so that EPS regenerated EPS beads. [14][15][16][17] The EPS is used twice to improve the utilization of polystyrene; however, this method requires 400 C, which increase the cost of production and energy consumption, contrary to the concept of low carbon.…”