Polycarbonate Nanocomposites Research Articles

Polycarbonate nanocomposite fibres and thin films with versatile morphological, optical and thermal properties

Polymer nanocomposites are versatile materials with wide variety of applications. The present contribution elaborately discussed about the preparation and characterization of polycarbonate (PC) nanocomposites incorporated with oleic acid (OA) capped cadmium sulphide (CdS) nanoparticles. The variation in properties based on the surface area of polymer composites was studied by the preparation of both nanofibres and thin films. It was observed that the properties are in close relation with the surface morphology of the prepared composite materials. The composites exhibit absorption in the ultraviolet as well as in the visible region of the spectrum. Quenching of emission in the ultraviolet region with a simultaneous increase of emission in the visible region by the addition of filler content was observed. The thermal stability gradually increased with increase of nanofiller content. The glass transition temperatures of PC nanocomposite fibres and thin films were also increased by the increase of CdS nanoparticles.

SnS2/Polycarbonate Nanocomposites: Structural and Optical Characterizations

Undoped and doped polycarbonate (PC) polymer nanocomposites with nano tin disulfide (SnS2) were synthesized by the thermolysis and casting methods. The effect of nano SnS2 doping on the absorption behavior of polycarbonate nanocomposites was studied in details using Fourier transform infrared spectroscopy technique. Structural analysis for undoped and doped films was investigated using X-ray diffraction technique. Detailed absorption measurements were performed in the wavelength range of 200–800 nm using UV spectroscopy technique. Results showed that our nanocomposites films exhibited a direct optical energy gap that decreased from 4.68 to 4.32 eV with the increment of the doping concentration up to 5 wt%. The optical constants of polymer nanocomposites such as absorption coefficient, extinction coefficient, refractive index, dielectric constant, average oscillator strength and wavelength revealed an enhancement in the optical values of polymer nanocomposites compared with undoped polymer. The improvement in the refractive index values with the doping content revealed the uniform distribution of the nanoparticles within the PC matrix. Scanning electron microscope images confirmed these results. Wemple–Didomenico single oscillator model was applied in order to examine different dispersion parameters such as single-oscillator and dispersion energies, the high frequency dielectric constant and the ratio of free charge carrier amount to the effective mass. The resulting improvements in the optical properties of the inspected polymer nanocomposites referred to the possibility of future usage as UV blocking materials in the industry such as contact lenses and optoelectronic devices.

Tailoring the surface of attapulgite by combining redox-initiated RAFT polymerization with alkynyl-thiol click reaction for polycarbonate nanocomposites:Effect of polymer brush chain length on mechanical, thermal and rheological properties

In this work, we proposed the tuning of the interface between attapulgite (ATP) and polycarbonate (PC) by the surface tailoring of ATP via a combination of RAFT polymerization and alkynyl-thiol click reaction. The side alkynyl-functionalized random copolymer poly(MMA-co-PgMA) was synthesized as the immobilization block via redox-initiated room-temperature RAFT copolymerization of MMA and propargyl methacrylate (PgMA). Then, the dispersion block was synthesized by room-temperature RAFT polymerization of MMA using poly(MMA-co-PgMA) as the macro chain transfer agent to afford poly((MMA-co-PgMA)-b-MMA). FTIR, 1H NMR, gel permeation chromatograph (GPC), and kinetic results indicated the successful synthesis of copolymers with well-defined structures. Copolymers with different length of PMMA segment were tethered onto the surface of thiol-functionalized ATP via alkynyl-thiol click reaction to mediate the interfacial interaction between ATP and PC, the successful covalent grafting of copolymers was confirmed by FTIR, TGA, XPS and XRD, and the effects of dispersion blockchain length on nanocomposites were investigated. The functionalized ATP demonstrated an improved dispersity in nanocomposites and enhanced mechanical properties with increasing dispersion blockchain length. The PC nanocomposites with functionalized ATP showed lower Tg and complex viscosity as compared to that of pure PC and nanocomposites with bare ATP, which enhanced the processability of nanocomposites.

Encouraging mechanical reinforcement in polycarbonate nanocomposite films via incorporation of melt blending-prepared polycarbonate-graft-graphene oxide

In this work, we are looking for a facile way to solve the dissatisfactory compatibility of graphene oxide (GO) with polycarbonate (PC) and prepare a sort of PC/GO nanocomposite possessing satisfactory mechanical properties. Graft modification of GO was conveniently achieved by transesterification reaction during melt blending process between GO and PC. Afterwards, PC nanocomposite films were fabricated via solvent casting method. The prepared PC-graft-GO achieved uniform distribution in the PC matrix and it was found to be a high-efficient reinforcing nanofiller, up to 49% increment in tensile strength and 47% increment in Young’s Modulus of PC nanocomposite films were observed at a content of 1.0 wt% PC-graft-GO. The reinforcement was caused not only by the bearing effect of GO layers itself but also by the nucleating crystallization effect of the PC-graft-GO, further studies indicated that PC-graft-GO could serve as a nucleating agent and induce the crystallization of PC during solvent casting preparation.

A new cooperative model for the prediction of compressive yield stress of polycarbonate nanocomposites considering strain rate, temperature, and agglomeration

In this study, a new model was proposed to predict the compressive yield stress of polycarbonate nanocomposite reinforced by nanoparticles at different strain rates, temperatures, and filler contents. In addition, the proposed model makes it possible to calculate the critical filler content for which the agglomeration phenomena occur. For the validation of the model, a series of experiments were performed. At first, the modified nanoclay Cloisite 20A masterbatch was produced by a direct method using extrusion machine, and the graphene oxide masterbatch was produced by the solvent method. Then the composite samples were produced using the injection-molding process, and the compressive tests were performed at three temperatures under quasi-static and dynamic loadings using a universal testing machine and split Hopkinson pressure bar. The coefficients of the proposed modified cooperative model were calculated using the experimental results. The observations showed that the presented model could correlate the compressive yield stress of polycarbonate nanocomposites to strain rate, temperature, and filler content with sufficient accuracy. Furthermore, the agglomeration of nanoparticles in polymer matrix which is a critical issue in fabrication of the advanced nanocomposites is predictable by using the current model.

Mechanical characterization of polycarbonate reinforced with nanoclay and graphene oxide

In this research, the effect of organic nanoclay (NC) Closite 20A and graphene oxide (GO) on the compressive, tensile, and three‐point bending behavior of polycarbonate (PC) nanocomposites is investigated. The nanocomposite samples are prepared based on injection molding and the masterbatch technique is used for better dispersion of filler in the matrix. The NC masterbatch is made of direct method by the twin‐screw extruder device and the GO masterbatch by the solvent method. The results showed that the presence of nanoparticles in the composite improves the elastic modulus, flexural modulus, compressive and tensile yield stress. The best weight fractions between the considered values for PC/NC and PC/GO were 1% and 0.6%, respectively. Higher fractions lead to the formation of agglomerate and degradation of the nanocomposite. Additionally, it was found that the volume change in plastic deformation for thermoplastics was considerable and the assumption of non‐dependent potential flow for PC nanocomposites was more appropriate. For simulating the mechanical behavior of PC nanocomposite, the extended Drucker–Prager (EDP) material model was designated and its coefficient were determined by minimizing the difference between the force‐displacement curves obtained from three‐point bending test and predicted from numerical simulation using the surrogate method. POLYM. COMPOS., 40:3947–3959, 2019. © 2019 Society of Plastics Engineers

Effects of nanoparticle size and concentration on optical, toughness, and thermal properties of polycarbonate

ABSTRACTThe influences of size and content of silicon dioxide (SiO2) nanoparticles on the morphological, optical, toughness, and thermal properties of polycarbonate (PC) were investigated. The PC nanocomposites were prepared using a twin‐screw extruder followed by injection molding. The scanning electron microscope (SEM) micrographs displayed an adequate level of nano‐SiO2 particle distribution within the PC matrix but still revealed some agglomerated particles. Upon increasing the content of nanoparticles, slightly larger agglomerates formed. These agglomerated particles caused a reduction in material transparency due to light loss via reflection and scattering. However, the incorporation of nano‐SiO2 into the PC matrix greatly improved toughness properties and slightly increased glass‐transition temperature (Tg), in conjunction with filler content (up to 4 vol %). This was particularly in the case with the smaller sized nano‐SiO2, which not only significantly improved toughness but also enhanced optical properties of the PC nanocomposites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47634.

Thermomechanical characteristics of h-BN- and POSS-based bisphenol A polycarbonate nanocomposites

ABSTRACTThe effect of octaphenyl-substituted polyoligomeric silsesquioxane and hexagonal boron nitride on mechanical, thermal, and interfacial properties of polycarbonate (PC) has been discerned in conjunction with dissipative particle dynamics for assessing solubility parameter and energy of mixing. We have explored the utilization of in situ temperature-assisted small-angle scattering (SAXS) to glean the short-range ordered inhomogeneities and electron density distribution in PC after incorporation of POSS and h-BN. The thermomechanical attributes of PC were further evaluated via differential scanning calorimetry (DSC), temperature-modulated DSC, dynamic mechanical analysis followed by tensile testing and impact characterization in addition to micromechanical analysis.

Improve spectroscopic structural and AC electrical conductivity of PC/PEO blend using graphene

Abstract Nanocomposites of polycarbonate (PC) and polyethylene oxide (PEO) embedded with graphene oxide (GO) nanopowder have been prepared using casting method. Prepared nanocomposites are studied and investigated using different characterization techniques. The X-ray diffraction (XRD) pattern reveals the semi-crystalline nature of PC/PEO blend. There are no significant peaks characterizing pure graphene. The intensity of the main X-ray peak characterizing the blend is decreased with the increase of graphene content confirming a modification in the blend due to an addition of graphene oxide. The FT-IR spectra display the main characteristic IR bands due to vibrational function groups for the components. The Optical absorption spectra are measured as a function of wavelength in the range of 190–1100 nm. The UV/V spectra show two absorption bands at 290 and 620 nm due to electronic transitions. The value of E g is obtained using indirect transition and its decrease with increasing the amount of graphene. The behavior of e′ and e″ decreased with the increase of frequencies is observed. After adding graphene, the frequency is increased due to the dipole moment. The decrease of e″ with increases of both the frequency and the temperature attributed to the origin of e″ is the conduction losses. The decrease of dissipation factor (tan δ) is ascribed to the internal polarization mechanism related to applied frequencies. The maximum value of the peak at M″ relation explained as being the result of the distribution of relaxation time.

A Photoresponsive Hyaluronan Hydrogel Nanocomposite for Dynamic Macrophage Immunomodulation.

Macrophages are a predominant immune cell population that drive inflammatory responses and exhibit transitions in phenotype and function during tissue remodeling in disease and repair. Thus, engineering an immunomodulatory biomaterial has significant implications for resolving inflammation. Here, a biomimetic and photoresponsive hyaluronan (HA) hydrogel nanocomposite with tunable 3D extracellular matrix (ECM) adhesion sites for dynamic macrophage immunomodulation is engineered. Photodegradative alkoxylphenacyl-based polycarbonate (APP) nanocomposites are exploited to permit user-controlled Arg-Gly-Asp (RGD) adhesive peptide release and conjugation to a HA-based ECM for real-time integrin activation of macrophages encapsulated in 3D HA-APP nanocomposite hydrogels. It is demonstrated that photocontrolled 3D ECM-RGD peptide conjugation can activate αvβ3 integrin of macrophages, and periodic αvβ3 integrin activation can enhance anti-inflammatory M2 macrophage polarization. Altogether, an emerging use of biomimetic, photoresponsive, and bioactive HA-APP nanocomposite hydrogel is highlighted to command 3D cell-ECM interactions for modulating macrophage polarization, which may shed light on cell-ECM interactions in innate immunity and inspire new biomaterial-based immunomodulatory therapies.

Optically transparent and flame-retarded polycarbonate nanocomposite based on diphenylphosphine oxide-containing polyhedral oligomeric silsesquioxanes

Series of phosphorus-containing polyhedral oligomeric silsesquioxane (DPOP-POSSs) have been synthesized through hydrolytic condensation reactions. FTIR, NMR, and MALDI-TOF-MS were used to identify the structures of the DPOP-POSSs, which including T8, T9, and T10 cage structures. Excellent optically transparent polycarbonate PC/DPOP-POSSs nanocomposites can be achieved through simple twin-screw extrusion. The % transmittance of the PC control (83%) was decreased by 3–5% in the PC/DPOP-POSSs nanocomposites. The pyrolysis and fire behavior of PC/DPOP-POSSs nanocomposites have been investigated by TGA-FTIR, cone calorimetry, LOI and UL-94. PC/DPOP-POSSs-6 nanocomposites showed LOI values of 30.1% and V-0 rating. The flame-retardant performance and mechanisms of DPOP-POSSs have been assessed based on TGA-FTIR, XPS, and FTIR results and are discussed in detail. The main flame-retardant activity of DPOP-POSSs is due to formation of a framework of silicon and phosphorus in the condensed phase, which can improve the thermal stability, strength, and integrity of the char layer.

A Comparative Study of Multiwalled Carbon Nanotube Based Polystyrene and Toughened Polycarbonate Nanocomposites

A Comparative Study of Multiwalled Carbon Nanotube Based Polystyrene and Toughened Polycarbonate Nanocomposites

Influence of gamma radiation on optical properties of Halloysite nanotubes incorporated polycarbonate nanocomposites

ABSTRACTIn the current research investigation, polycarbonate/hallyosite nanotubes (PC/HNTs) nanocomposite (NC) films have been successfully fabricated by solution intercalation technique using ultrasound energy in facile way which helps complete exfoliation of the HNTs in the matrix. The effect of Gamma irradiation-induced modifications of PC/HNTs NC have been studied in the dose range 200–500 kGy, irradiated with Co60 source. The NC films have been evaluated by UV–visible spectroscopy, Fourier Transform Infrared spectroscopy, X-ray diffraction and scanning electron microscopic techniques in order to probe the effect of gamma radiation on the structural behaviors. The obtained results have been indicated that as the Gamma irradiation dosage increases from 200 to 500 kGy, phenolic group forms through scissoring of ester link of PC, which may cause PC to degrade and lose their property. At lower dosage (200 kGy), the effect is less and at higher dosage (500 kGy), the effect is significant and at 300 and 400 kGy, the effect is moderate and NC films retained their properties. The irradiation effect is most significant and effective at the higher dosage range. UV–visible spectroscopy shows a noticeable reduction in the energy band gap due to gamma irradiation.

Microinjection molding of multiwalled carbon nanotubes (CNT)–filled polycarbonate nanocomposites and comparison with electrical and morphological properties of various other CNT‐filled thermoplastic micromoldings

A series of polycarbonate (PC)/multiwalled carbon nanotubes (CNT) nanocomposites were prepared by diluting a commercially available masterbatch using a neat PC resin in a lab‐scale batch mixer. The obtained nanocomposites were subjected to microinjection molding to fabricate microparts, which have a 3‐step decrease in thickness along the flow direction, under a defined set of processing conditions. The obtained microparts were mechanically divided into 3 different sections, namely, thick, middle, and thin sections, based on thickness. Morphology observations and electrical conductivity measurements were conducted to explore the evolution of microstructure within subsequent microparts. Additionally, a comparison of the electrical and morphological properties of stepped microparts of various thermoplastic polymers filled with CNT was studied. Results suggested that the selection of host polymers influences the dispersion of nanotubes within subsequent moldings, thereby affecting the electrical properties. The thermal stability of subsequent moldings deteriorated upon the addition of CNT, suggesting that the addition of CNT and the thermomechanical history experienced by the polymer melts in microinjection molding might cause a chain scission effect on PC. Raman spectroscopy analysis was used to study the orientation and properties of CNT in microparts.

A review on the mechanical, electrical and EMI shielding properties of carbon nanotubes and graphene reinforced polycarbonate nanocomposites

Recently, it has been found that carbon nanotubes (CNTs) and graphene could prove to be the most promising carbonaceous fillers in polymers nanocomposites field because of their better structural and functional properties. Their uniform dispersion in polymer matrix leads to significant improvements in their several properties. This paper reviews the effect of nanofillers, ie, CNTs, derivatized CNTs, and graphene on the polycarbonate nanocomposite and its application in aerospace, automobile, sports, electronic sectors, and various industries. The comparative analysis of carbon‐based fillers on the different properties of polycarbonate nanocomposites is also included.

Luminescent down-shifting aluminosilicate nanocomposites: an efficient UVA shielding material for photovoltaics

In this investigation polycarbonate (PC) nanocomposites (NC) films have been fabricated with varying amounts of alluminosilicate nanotubes (HNT) using solvent intercalation method. On the basis of UV–Vis experiments, the effect of HNT on absorption coefficient spectra of PC/HNT NC films is demonstrated. A distinct reduction of band gap energy is being a result of HNT doping which leads to the formation of charge transfer complexes (CTC) and π-conjugation between HNT and PC matrix. Further absorption bands and absorption edge parameters such as Urbach energy (Eu) and energy gap (Eg) are used to evaluate the changes in the NC films. The structural and morphological aspects of PC/HNT NC were evaluated by Fourier transform infrared spectroscopy, X-Ray diffraction studies and scanning electron microscopy. Absorbance and transmittance spectra of luminescent PC/HNT NC films reveals the conversion of higher energy UVA light in to lower energy visible light which leads to efficient photovoltaic application.

An Investigation on Transparency and Mechano-Acoustic Properties of Poly Methyl Methacrylate/Polycarbonate Based Nanocomposites

The main goal of this paper was to investigate transparency and mechano-acoustic properties of poly methyl methacrylate (PMMA)/polycarbonate (PC) based nanocomposites, reinforced with silica (SiO2), zinc dioxide (ZnO), and titanium dioxide (TiO2) nanoparticles. For this purpose, morphological, transparency, acoustical and mechanical tests were carried out on the specimens, prepared by melt-compounding method in a twin-screw extruder. The morphological test results confirmed uniform dispersion of the nanoparticles in the polymer matrix. The results also revealed that transparency of the PC and PMMA nanocomposites, characterized by the degree of light transmittance, was decreased by adding 0.3 wt% of the nanoparticles. Also, tensile modulus of the nanocomposite specimens was higher than that of neat PC and PMMA. Unlike the neat PC specimens, tensile strength showed a decrease in PMMA specimens. The presence of nanoparticles in the composites decreased mobility of polymer chains and consequently, reduced elongation at break in the specimens. After surface roughening process, noise absorption coefficient in PC/PMMA nanocomposite specimens (PCSI3-R, PMSI3-R, and PMZN3-R) showed a higher absorption coefficient than the other specimens in the dominant frequency of traffic noise (500 Hz). As conclusion, roughening the surface of materials would be one of the most important factors enhancing the absorption coefficient of some of the nanocomposites in the middle frequency. The rough surface of particles in the base matrix increases the absorption coefficient of the materials, especially in the frequency of 500 Hz, as the dominant frequency of noise traffic. The suggested materials are predestinated to be appropriate in building industry, particularly in the structure of noise barriers.

Improving Impact Strength in FSW of Polymeric Nanocomposites Using Stepwise Tool Design

ABSTRACTIn recent years, many studies have been conducted on process parameters of polymers friction stir welding, while material parameters are still facing serious problems especially in polymeric nanocomposites. In the present study, the impact behavior of friction stir–welded polycarbonate (PC) nanocomposites under different material and process conditions has been investigated using Taguchi approach. A stepwise tool design procedure has been carried out to enhance the welding process. The samples containing various weight percentages of alumina nanoparticles have been welded under different welding process parameters. The analysis of variance results illustrated that nanoalumina content is the most effective parameter on impact strength followed by rotational and transverse speeds. Impact strength of welded samples was conspicuously improved up to 15% by adding 2 wt% of nanoalumina compared with pure PC samples. Also increasing rotational speed and decreasing transverse speed leads to increase of impact strength. In order to optimize the process, signal-to-noise ratio analysis was performed. The results indicated that the optimum levels of input parameters that give the maximum impact strength are as following: 2 wt% of nanoalumina, 2500 rpm of rotational speed, and 8 mm/min of transverse speed which causes 26.14% improvement in impact strength of samples.

Characterization and micro end milling of graphene nano platelet and carbon nanotube filled nanocomposites

Graphene and carbon nanotubes (CNTs) have been used in polymeric nanocomposites for improved mechanical, electrical, thermal and gas barrier properties. As the major applications of these relatively new materials are expected to be in the micro/meso-scale, their micro-machinability needs to be investigated. In this study, graphene nano platelet (GNP) and multi-walled carbon nanotube (MWCNT) filled polycarbonate (PC) nanocomposites were fabricated through injection molding. The molded nanocomposites were characterized for their thermal and mechanical properties. Micro mechanical machining was performed on the molded specimens to understand the material removal behavior. The micro cutting forces were measured and compared for the fabricated GNP and MWCNT filled nanocomposites. The experimental results showed that the GNP filled PC nanocomposites required higher cutting forces than plain PC. The chip morphologies of the materials were explored under scanning electron microscopy. Finite element (FE) model of machining PC and PC-GNP nanocomposites was developed to determine the fundamental mechanisms of chip formation and surface generation due to the inclusion of the GNP fillers. The FE model was validated by the comparison of simulated and experimental micro milling forces. The results of this study show that the addition of GNP and MWCNT can significantly improve the dimensional accuracy and the quality of the machined surfaces.

Polycarbonate toughening with reduced graphene oxide: Toward high toughness, strength and notch resistance

The toughening effect of graphene sheets on polycarbonate (PC) was investigated to fabricate PC composites with excellent balanced toughness, notch resistance as well as strength. The reduced graphene oxide (RGO) was incorporated into PC matrix through melt compounding. A maximum toughening effect was observed in PC/RGO (PCG) composites with 0.03wt% or 0.07wt% RGO. Particularly, the tensile fracture toughness of PCG composites with 0.03wt% RGO was enhanced by 89%. The notched impact strength and KIC of PCG composite with 0.07wt% RGO was increased by 46% and 58%, respectively. The point of 0.1wt% was found to be the ductile-brittle transition point in PCG composites. Meanwhile, the yield strength of these novel materials was increased by around 12% as well at loading of 0.07wt%. Microcrack, resulting from interfacial debonding between PC and RGO as well as breakage and pulling out of graphene layer, was proposed to be the main toughening mechanism contributing to the great enhanced fracture toughness and notch resistance. Apart from the microcrack, crack pinning, crack deflection and crack arresting were also found and proposed to be toughening mechanism in notch-fractured process. This work not only provides us a novel strategy to fabricate advanced PC nanocomposites but also gives us a deep understanding on the toughening role of graphene on polymers.