Polymer nanocomposite

About: Polymer nanocomposite is a research topic. Over the lifetime, 8977 publications have been published within this topic receiving 297599 citations.

Graphene Oxide/Polymer‐Based Biomaterials

Abstract: Since its discovery in 2004, derivatives of graphene have been developed and heavily investigated in the field of tissue engineering. Among the most extensively studied forms of graphene, graphene oxide (GO), and GO/polymer-based nanocomposites have attracted great attention in various forms such as films, 3D porous scaffolds, electrospun mats, hydrogels, and nacre-like structures. In this review, the most actively investigated GO/polymer nanocomposites are presented and discussed, these nanocomposites are based on chitosan, cellulose, starch, alginate, gellan gum, poly(vinyl alcohol) (PVA), poly(acrylamide), poly(ϵ-caprolactone) (PCL), poly(lactic acid) (PLLA), poly(lactide-co-glycolide) (PLGA), gelatin, collagen, and silk fibroin (SF). The biological and mechanical performance of such nanocomposites are comprehensively scrutinized and ongoing research questions are addressed. The analysis of the literature reveals overall the great potential of GO/polymer nanocomposites in tissue engineering strategies and indicates also a series of challenges requiring further research efforts.

Creep Resistant Polymer Nanocomposites Reinforced with Multiwalled Carbon Nanotubes

Abstract: Poly(propylene) (PP) nanocomposites filled with shorter- and longer-aspect-ratio multiwalled carbon nanotubes (MWNTs) were compounded using a twin-screw extruder and an injection moulding machine. It is shown that with only 1 vol.-% of MWNTs, creep resistance of PP can be significantly improved with reduced creep deformation and creep rate at a long-term loading period. Additionally, the creep lifetime of the nanocomposites has been considerably extended by 1000% compared to that of a neat PP. Three possible mechanisms of load transfer were considered that could contribute to the observed enhancement of creep resistance, which are: (1) fairly good interfacial strength between MWNTs and polymer matrix, (2) increasing immobility of amorphous regions due to nanotubes acting as restriction sites, and (3) high aspect ratio of MWNTs. DSC results showing crystallinity changes in the specimens before and after creep deformation present evidence to confirm these mechanisms. Our results should lead to improved grades of creep resistant polymer nanocomposites for engineering applications.

Polymer diffusion in a polymer nanocomposite: effect of nanoparticle size and polydispersity

Abstract: The tracer diffusion of deuterated polystyrene (dPS) is measured in a polystyrene nanocomposite containing silica nanoparticles (NPs), with number average diameters dn of 28.8 nm and 12.8 nm, using elastic recoil detection. The volume fractions of the large and small NPs (ϕNP) range from 0 to 0.5, and 0 to 0.1, respectively. At the same volume fraction of NPs, the tracer diffusion of dPS is reduced as NP size decreases because the interparticle distance between NPs (ID) decreases. The reduced diffusion coefficient, defined as the tracer diffusion coefficient in the nanocomposite relative to pure PS (D/D0), plotted against the confinement parameter, namely ID(dn) relative to tracer size, ID(dn)/2Rg, nearly collapses onto a master curve, although D/D0 is slightly greater for the more polydisperse, smaller NPs. Using a log normal distribution of NP size from SAXS, the average ID of the smaller NPs is shown to increase by 25% at ϕNP = 0.1 as polydispersity (σ) increases from 1 to 1.39. By accounting for polydispersity, the confinement parameter better represents the effect of NP spacing on polymer diffusion. These experiments demonstrate that polymer tracer diffusion in polymer nanocomposites is empirically captured by the confinement parameter and that an increase in the average ID due to NP polydispersity has a secondary effect on model NP systems with a narrow distribution of sizes. However, for commercial systems, where polydispersity can be quite large, the effect of size distribution can significantly increase ID which in turn will influence polymer dynamics.

Effects of iron oxide nanoparticles on polyvinyl alcohol: interfacial layer and bulk nanocomposites thin film

Abstract: Iron oxide (α-phase) nanoparticles with coercivity larger than 300 Oe have been fabricated at a mild temperature by an environmentally benign method. The economic sodium chloride has been found to effectively serve as a solid spacer to disperse the iron precursor and to prevent the nanoparticles from agglomeration. Higher ratios of sodium chloride to iron nitrate result in smaller nanoparticles (19 nm for 20:1 and 14 nm for 50:1). The presence of polyvinyl alcohol (PVA) limits the particle growth (15 nm for 20:1 and 13 nm for 50:1) and favors nanoparticle dispersion in polymer matrices. Obvious physicochemical property changes have been observed with PVA attached to the nanoparticle surface. With PVA attached to the nanoparticle surface, the nanoparticles are found not only to increase the PVA cross-linking with an increase in melting temperature but also to enhance the thermal stability of the PVA. The nanoparticles are observed to be uniformly dispersed in the polymer matrix. Scanning electron microscopy (SEM) microstructure also shows an intermediate phase with a strong interaction between the nanoparticles and the polymer matrices, arising from the hydrogen bonding between the PVA and hydroxyl groups on the nanoparticle surface. The addition of nanoparticles favors the cross-linkage of the bulk PVA matrices, resulting in a higher melting temperature, and an enhanced thermal stability of the polymer matrix.

Optical polymer nanocomposites

Abstract: A composite material that includes a host matrix and a plurality of dispersed nanoparticles within the host matrix. Each of the plurality of nanoparticles may include a halogenated outer coating layer that seals the nanoparticle and prevents agglomeration of the nanoparticles within the host matrix. The invention also includes a process of forming the composite material. Depending on the nanoparticle material, the composite material may have various applications including, but not limited to, optical devices, windowpanes, mirrors, mirror panels, optical lenses, optical lens arrays, optical displays, liquid crystal displays, cathode ray tubes, optical filters, optical components, all these more generally referred to as components.