Preparation and characterization of carbon nanofiber reinforced thermoplastic polyurethane nanocomposites

Abstract

The effect of CNFs on hard and soft segments of TPU matrix was evaluated using Fourier transform infrared (FTIR) spectroscope. The dispersion and distribution of the CNFs in the TPU matrix were investigated through wide angle X-ray diffraction (WAXD), field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), polarizing optical microscope (POM), and atomic force microscope (AFM). The thermogravimetric analysis (TGA) showed that the inclusion of CNF improved the thermal stability of virgin TPU. The glass transition temperature (T g ), crystallization, and melting behaviors of the TPU matrix in the presence of dispersed CNF were observed by differential scanning calorimetry (DSC). The dynamic viscoelastic behavior of the nanocomposites was studied by dynamical mechanical thermal analysis (DMTA) and substantial improvement in storage modulus (E') was achieved with the addition of CNF to TPU matrix. The rheological behavior of TPU nanocomposites were tested by rubber processing analyzer (RPA) in dynamic frequency sweep and the storage modulus (G') of the nanocomposites was enhanced with increase in CNF loading. The dielectric properties of the nanocomposites exhibited significant improvement with incorporation of CNF. The TPU matrix exhibits remarkable improvement of mechanical properties with addition of CNF. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124: [765][766][767][768][769][770][771][772][773][774][775][776][777][778][779][780] 2012

Novel electrically conductive polyurethane/montmorillonite-polypyrrole nanocomposites

“…XRD curves of the neat TPU ( Figure 6) exhibits a large and intense diffraction peak centered at 2$ = 19.98° assigned to the reflection plane (110) with dvalue of 0.45 nm. This diffraction pattern can be attributed to the irregular segments of the amorphous phase and, chains arranged on short-range of the TPU rigid phase, respectively [52,53]. According to Ramôa et al [41] the neat Mt used in this study manifests a crystalline peak at 6.3° (2$) assigned to the periodicity in the (001) direction of neat Mt and d-value is 1.4 nm.…”

Isotactic polypropylene–vapor grown carbon nanofibers composites: Electrical properties

“…The raw materials are isotactic polypropylene iPP (Marlex HLN‐120–01) purchased from Philips Sumika Polypropylene Company (iPP) and vapor grown carbon nanofibers (VGCNFs) with diameters ranging between 60 and 100 nm and lengths between 30,000 and 100,000 nm, generously supplied by Pyrograf Products, Inc. (PR‐24AG). VGCNFs were chemically treated (refluxed in dichloromethane and distilled water) to debundle and purify the nanofibers while the polymer was used as received . iPP‐VGCNF containing various amounts of VGCNFs have been obtained by melt mixing using a Haake Rheomix equipment with two‐counter rotating screws.…”

The use of atomic force microscopy as an important technique to analyze the dispersion of nanometric fillers and morphology in nanocomposites and polymer blends based on elastomers

“…The main factors of mechanical energy dissipation of the tip and consequent phase change are the viscoelastic, adhesive and topographical properties of the region being examined. In addition, it allows to obtain new information about the polymers surface such as tribological data [3] , local contaminants [6] , morphology [17, , distribution of phases in blends and composites [41][42][43][44][45][46][47] , compatibility between the phases of polymer blends and interaction between nanocomposites phases [48][49][50][51][52][53][54] , polymeric chains conformation [7,38] , cross-link density [55][56][57] , dispersion of fillers in the polymeric matrix [10,12,16,48,49,[58][59][60][61][62][63][64][65][66][67][68][69] , among other applications.…”

“…Barick and Trupathy [53] prepared nanocomposites TPU/ Carbon Nanofibers (CNFs) by melt intercalation technique followed by compression molding, and analyzed the dispersion of the CNFs in the matrix by different techniques, including AFM. According to the AFM images, CNFs presented a high level of dispersion via either covalent or ionic bonds between CNF and TPU.…”