Dispersion Of Nanofillers In Matrix Research Articles

Effect of surfactants on swelling capacity and kinetics of alginate-chitosan/CNTs hydrogel

Nanocomposite hydrogels of alginate-chitosan matrix with nanofillers, functionalized multi-walled carbon nanotubes (COOH-MWCNTs) were first time synthesized in cationic, anionic, mixture of cationic and anionic surfactants and in the absence of surfactants by employing solution casting method. Whole process of synthesis was carried out under greener source of heating i.e., ultrasonic waves. Synthesized films were evaluated by Fourier transform infrared spectroscopy and scanning electron microscopy which reveal uniform dispersion of nanofillers in matrix. Synthesized hydrogels were also newly explored for swelling capacity. Swelling ratio of hydrogels was measured in distilled water, saline solutions and in solutions of different pH. Swelling pattern of prepared films indicates that these materials are very stable and can show best performance in different pH and kinds of solutions. Effect of concentration ratio of nanofillers to matrix and nature of surfactants on swelling ability was also appraised and indicated that trace amount of nanofillers gives fascinating results. Process of swelling and deswelling of synthesized films was taken place by super case-II transport mechanism, which is effected by amount of nanofillers and nature of surfactant.

Buckypaper of polyvinyl chloride/p‐phenylenediamine modified graphite and PVC/graphite via resin infiltration technique

Resin‐infiltration technique has been employed as a versatile method to improve nanofiller dispersion in matrix. In this article, fabrication of polyvinyl chloride (PVC)/p‐phenylenediamine (PPD)/functional graphite (F‐G) and PVC/F‐G composite paper have been reported through resin‐infiltration techniques. Synthesis and characterization of PVC/PPD/F‐G and PVC/F‐G composite papers for enhanced structural, morphological, thermal, hardness, wettability, and conductivity properties have been studied. Moreover, the effect of increasing amount of F‐G and PPD/F‐G nanofiller on composite paper properties was scrutinized and compared. Transmission electron microscopy and scanning electron microscopy depicted better graphite nanofiller dispersion in PVC matrix and network formation in PVC/PPD/F‐G composite paper. Maximum degradation temperature (Tmax) of PVC/PPD/F‐G 0.08 composite paper (517°C) was found higher than PVC/F‐G 0.08 composite paper (484°C). Dynamic contact angle analysis shows that the PVC/PPD/F‐G and PVC/F‐G composite papers have better surface wettability than neat PVC. PVC/PDD/F‐G 0.1 and PVC/F‐G 0.1 composite papers possess high microhardness values up to 39.67 and 32.76 Hv, respectively. Electrical conductivity of 8.97 × 10−3 and 5.89 × 10−3 S m−1 was observed for 0.08 wt% PPD/F‐G and F‐G loaded samples. POLYM. COMPOS., 39:4176–4187, 2018. © 2017 Society of Plastics Engineers

Effects of compatibilizer, compounding method, extrusion parameters, and nanofiller loading in clay‐reinforced recycled HDPE/PET nanocomposites

ABSTRACTNanocomposites based on recycled high density polyethylene (rHDPE), recycled polyethylene terephthalate (rPET), and organoclay (C10A) were made using twin screw extruder followed by hot pressing. The independent effects of polymer/clay compatibility, preparation method, extrusion parameters, and clay loadings were investigated. Ethylene‐glycidyl methacrylate could effectively improve the compatibilization of immiscible rHDPE/rPET blend with clay, which confirmed by the good polymers‐clay adherence and domain size reduction obtained in scanning electron microscopy images. Although intercalated structures were observed in the composites made by one‐step compounding, in the composites prepared by two‐step extrusion method, enhanced dispersion of clay in polymer blend was found from X‐ray diffraction results. Higher extrusion temperature and intermediate speed of rotation (90 rpm) appeared to increase the mechanical properties due to improvement of nanofiller dispersion in matrix. Results showed that the stiffness increased whereas tensile and impact strength decreased with clay content. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42287.

Studies on synergistic effect of CNT and CB nanoparticles on PVDF

Poly(vinylidene fluoride) (PVDF) nanocomposites with different loading of carbon nanotubes (CNT) and carbon black (CB) were prepared by melt blending method. The conductivity and mechanical properties of the nanocomposites were investigated. The results showed that percolation threshold of CNT/CB/PVDF nanocomposites appeared at a lower concentration (1.25 vol% CNT) than that of CNT/PVDF (>2.08 vol% CNT). The tensile strength of CNT/CB/PVDF nanocomposites was also improved, with 32.1% increase compared to PVDF and 18.0% increase compared to CNT/PVDF at loading of 1.25 vol% CNT/0.96 vol% CB. To explore the synergistic effect of CNT and CB, nonisothermal crystallization and isothermal crystallization behaviors of PVDF and its nanocomposites were studied by differential scanning calorimetry, and the crystallization morphology of them was observed under the three dimensional digital microscope with the polarized model. The crystallization rate of PVDF was speeded up markedly because of heterogeneous nucleation effect of nanoparticles, and CNT and CB nanoparticles had a synergistic effect on nucleation. Polarized microscope observation confirmed that spherulite size of PVDF became smaller owing to the accelerating of crystallization, which influenced the distribution of nanoparticles. The dispersion of nanofillers in matrix was observed by scanning electron microscope. It was revealed that CB could make CNT disperse more evenly in the PVDF matrix. The synergies network of CNT and CB is suggested to build in matrix, which improved conductivity and mechanical properties of PVDF nanocomposites. POLYM. COMPOS., 36:2248–2254, 2015. © 2014 Society of Plastics Engineers