Polylactic acid (PLA)/halloysite nanotube (HNT) composite mats: Influence of HNT content and modification

Polylactic acid (PLA)/halloysite nanotube (HNT) composite mats were successfully fabricated via electrospinning. Composite mats reinforced by both unmodified and modified HNTs with a dispersant BYK-9076 were prepared at the HNT contents of 0, 1, 5 and 10 wt%/v. The influence of HNT content and modification was investigated comprehensively, based on several characterisation techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, mechanical testing, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). Typical modified Halpin–Tsai model and modified Halpin–Tsai laminate hybrid model in conventional composite theory were used, which were found difficult to predict the entire experimental data of elastic moduli for PLA/HNT composite mats, possibly arising from the nanosized effect of HNTs and some electrospun PLA nanofibres within composite mats

Regenerated cellulose/halloysite nanotube nanocomposite films prepared with an ionic liquid

Novel nanocomposite films based on regenerated cellulose/halloysite nanotube (RC/HNT) have been prepared using an environmentally friendly ionic liquid 1-butyl-3-methylimidazolium chloride (BMIMCl). The structural, morphological, thermal and mechanical properties of the RC/HNT nanocomposites were investigated using x-ray diffraction (XRD), fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), thermal analysis, and tensile strength measurements. The results obtained revealed interactions between the halloysite nanotubes (HNT) and regenerated cellulose (RC) matrix. The Young’s modulus and tensile strength increased from 1.8 to 4.1 GPa and from 35.30 to 60.50 MPa respectively when 8 wt% (HNT) was incorporated, interestingly without loss of ductility. This indicated higher toughness of the nanocomposites compared to RC. Lower water absorption and higher water contact angle indicated an improved hydrophobicity of RC/HNT nanocomposites compared to RC. The thermal stability and oxygen barrier properties of the nanocomposite films were significantly improved compared with pure RC film

Development of regenerated cellulose/halloysite nanotube bionanocomposite films with ionic liquid

In this study, novel nanocomposite films based on regenerated cellulose/halloysite nanotube (RC/HNT) have been prepared using an environmentally friendly ionic liquid 1-butyl-3-methylimidazolium chloride (BMIMCl) through a simple green method. The structural, morphological, thermal and mechanical properties of the RC/HNT nanocomposites were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), thermal analysis and tensile strength measurements. The results obtained revealed interactions between the halloysite nanotubes and regenerated cellulose matrix. The thermal stability and mechanical properties of the nanocomposite films, compared with pure regenerated cellulose film, were significantly improved When the halloysite nanotube (HNT) loading was only 2 wt.%, the 20% weight loss temperature (T-20) increased 20 degrees C. The Young's modulus increased from 1.8 to 4.1 GPa, while tensile strength increased from 35.30 to 60.50 MPa when 8 wt.% halloysite nanotube (HNT) was incorporated, interestingly without loss of ductility. The nanocomposite films exhibited improved oxygen barrier properties and water absorption resistance compared to regenerated cellulose. (C) 2013 Elsevier B.V. All rights reserved

Recent developments in montmorillonite and sepiolite filled regenerated cellulose nanocomposites: characterizations and properties

In recent years, the development of environmentally friendly materials obtained from renewable resources has attracted enormous attention due to the new sustainable development policies. Cellulose is a readily available, naturally occurring biodegradable and biocompatible linear polysaccharide. Recently, room temperature ionic liquids have been used as solvents to produce regenerated cellulose (RC) due to their attractive properties such as good chemical and thermal stability, low flammability, low melting point and ease of recycling. Polymer/nanofiller nanocomposites are believed to have strong potential to widen polymer applications due to its enhanced performance. It is also widely accepted that the incorporation of small amount of nanofiller (less than 5 wt.%) into bio-based matrices results in nano-biocomposite materials with enhanced mechanical, permeability and thermal properties. Montmorillonite (MMT) has a nanosized layered structure with large surface area thus providing sufficient interfacial regions in polymer nanocomposite. Besides, the needle like fibers based, natural hydrous magnesium silicate sepiolite has also been investigated due to its high surface area, unique geometry and its ability to form the hydrogen bonding with polymers as well as to disperse well in the matrix. This chapter aims to highlight the effect of the addition of two different types of nanofillers such as organically modified MMT and sepiolite to produce RC nanocomposites, on selected properties

Fabrication of composite polymer particles by stabilizer-free seeded polymerization

This paper reports the fabrication of polymer composite particles through stabilizer-free seeded polymerization. Various monomers were polymerized in the presence of submicron sodium styrene sulfunate-functionalized polystyrene seed particles without using swelling agent, emulsifier, or stabilizer. It was found that stable monodisperse composite particles are obtained even without using any ionic comonomer provided that the used monomer is nonpolar enough to facilitate swelling of the seeds. Utilizing the proposed method, copolymerization of styrene/divinyl benzene was successfully performed, resulting in highly crosslinked composite particles. Interestingly, Janus amphiphilic particles were achieved after the extraction of polystyrene by toluene from the particles. Overall, it is demonstrated that the proposed approach can be adopted as a facile and green process for the fabrication of various composite Janus particles

Regenerated cellulose/epoxidized natural rubber blend film

Regenerated cellulose/epoxidized natural rubber (ENR-50) blended films were prepared using an environmentally friendly ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIMCl). The films were obtained by casting solution method. The hydrogen bonding interactions between epoxy groups in ENR with hydroxyl groups of the RC in the blends were investigated by Fourier transforms infrared (FTIR) spectroscopy. Field emission scanning electron microscopy (FESEM) revealed that ENR dispersed homogenously within the RC matrix. The blends show significant enhancement of thermal stability as compared to the regenerated. The elongation at break remarkably improved by about 39% at 20 wt.% loading of ENR in dry state. This work demonstrates an effective approach to processing biodegradable regenerated cellulose and epoxidized natural rubber blend. (C) 2013 Elsevier B.V. All rights reserved

Regenerated cellulose nanocomposites reinforced with exfoliated graphite nanosheets using BMIMCL ionic liquid

Green nanocomposites of regenerated cellulose/exfoliated graphite nanosheets films with low nanofiller loadings were prepared using environmentally benign 1-butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid. X-ray diffraction revealed well developed intercalated nanocomposites. The tensile strength and Young's modulus of the prepared nanocomposites were increased by 97.5% and 172% respectively when 0.75 wt.% and 1 wt.% exfoliated graphite nanosheets were added. The results were validated using the Halpin-Tsai model. The exfoliated graphite nanosheets were unidirectionally aligned in the regenerated cellulose parallel to the surface of the nanocomposites as revealed by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Also, the TEM and FESEM revealed uniform dispersion of the exfoliated graphite nanosheets and good interaction between the nanofillers and the matrix. The addition of the exfoliated graphite nanosheets enhanced the thermal stability and reduced the water absorption and diffusivity of the nanocomposites