Nanotubes as polymer composite reinforcing additive materials – A comparative study

Multiscale Carbon Fibre-Carbon Nanotube Composites of Poly(Vinyl Chloride)-An Evaluation of Their Properties and Structure

To date, there has been limited information in the literature on the application of carbon fibre-carbon nanotube systems for the modification of poly(vinyl chloride) (PVC) matrixes by micro- and nanometric fillers and an evaluation of the properties of the unique materials produced. This paper presents the results of newly designed unique multiscale composites. The advantages of the simultaneous use of carbon fibres (CFs) and carbon nanotubes (CNTs) in PVC modification are discussed. To increase the dispersibility of the nanofiller, CFs together with nanotubes were subjected to a sonication process. The resulting material was introduced into PVC blends, which were processed by extrusion. The ratio of components in the hybrid filler with CF_CNT was 20:1, and its proportion in the PVC matrix was 1, 5, and 10 wt.%, respectively. Comparatively, PVC composites modified only with carbon fibres were obtained. The structure, thermal, electrical, and mechanical properties and swelling resistance of the composites were studied. The study showed a favourable homogeneous dispersion of nanotubes in the PVC matrix. This enabled effective modification of the structure at the nanometric level and the formation of an interpenetrating network of well-dispersed hybrid filler, as evidenced by a decrease in volume resistivity and improvement in swelling resistance, as well as an increase in glass transition temperature in the case of PVC/CF_CNT composites.

Recent advancement in polymer/halloysite nanotube nanocomposites for biomedical applications

Halloysite nanotubes (HNTs) have recently been the subject of extensive research as a reinforcing filler. HNT is a natural nanoclay, non-toxic and biocompatible, hence, applicable in biomedical fields. This review focuses on the mechanical, thermal, and functional properties of polymer nanocomposites with HNT as a reinforcing agent from an experimental and theoretical perspective. In addition, this review also highlights the recent applications of polymer/HNT nanocomposites in the biomedical fields.

Mechanical Performance and Applications of CNTs Reinforced Polymer Composites-A Review

Developments in the synthesis and scalable manufacturing of carbon nanomaterials like carbon nanotubes (CNTs) have been widely used in the polymer material industry over the last few decades, resulting in a series of fascinating multifunctional composites used in fields ranging from portable electronic devices, entertainment and sports to the military, aerospace, and automotive sectors. CNTs offer good thermal and electrical properties, as well as a low density and a high Young's modulus, making them suitable nanofillers for polymer composites. As mechanical reinforcements for structural applications CNTs are unique due to their nano-dimensions and size, as well as their incredible strength. Although a large number of studies have been conducted on these novel materials, there have only been a few reviews published on their mechanical performance in polymer composites. As a result, in this review we have covered some of the key application factors as well as the mechanical properties of CNTs-reinforced polymer composites. Finally, the potential uses of CNTs hybridised with polymer composites reinforced with natural fibres such as kenaf fibre, oil palm empty fruit bunch (OPEFB) fibre, bamboo fibre, and sugar palm fibre have been highlighted.

CVD Conditions for MWCNTs Production and Their Effects on the Optical and Electrical Properties of PPy/MWCNTs, PANI/MWCNTs Nanocomposites by In Situ Electropolymerization

In this work, the optimal conditions of synthesizing and purifying carbon nanotubes (CNTs) from ferrocene were selected at the first stage, where decomposition time, argon fluxes, precursor amounts, decomposition temperature (at 1023 K and 1123 K), and purification process (HNO₃ + H₂SO₄ or HCl + H₂O₂), were modulated through chemical vapor deposition (CVD) and compared to commercial CNTs. The processing temperature at 1123 K and the treatment with HCl + H₂O₂ were key parameters influencing the purity, crystallinity, stability, and optical/electrical properties of bamboo-like morphology CNTs. Selected multiwalled CNTs (MWCNTs), from 1 to 20 wt%, were electropolymerized through in-situ polarization with conductive polymers (CPs), poly(aniline) (PANI) and poly(pyrrole) (PPy), for obtaining composites. In terms of structural stability and electrical properties, MWCNTs obtained by CVD were found to be better than commercial ones for producing CPs composites. The CNTs addition in both polymeric matrixes was of 6.5 wt%. In both systems, crystallinity degree, related to the alignment of PC chains on MWCNTs surface, was improved. Electrical conductivity, in terms of the carrier density and mobility, was adequately enhanced with CVD CNTs, which were even better than the evaluated commercial CNTs. The findings of this study demonstrate that synergistic effects among the hydrogen bonds, stability, and conductivity are better in PANI/MWCNTs than in PPy/MWCNTs composites, which open a promissory route to prepare materials for different technological applications.