Hydrogels for biomedical applications.

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (±10% or less) about the sample average with only few outliers. The thermal conductivity of the nanofluids was found to increase with particle concentration and aspect ratio, as expected from classical theory. There are (small) systematic differences in the absolute values of the nanofluid thermal conductivity among the various experimental approaches; however, such differences tend to disappear when the data are normalized to the measured thermal conductivity of the basefluid. The effective medium theory developed for dispersed particles by Maxwell in 1881 and recently generalized by Nan et al. [J. Appl. Phys. 81, 6692 (1997)], was found to be in good agreement with the experimental data, suggesting that no anomalous enhancement of thermal conductivity was achieved in the nanofluids tested in this exercise.

A Benchmark Study on the Thermal Conductivity of Nanofluids

An overview of microplastic and nanoplastic pollution in agroecosystems.

Cellulose nanocrystals and cellulose nanofibrils based hydrogels for biomedical applications.

Nanocellulose: Extraction and application

Nano-sized cellulose materials has recently become topical in the sphere of sustainable materials. The two key groups of nanocelluloses (NCs) are (1) nanofibrillated cellulose (NFC) and (2) cellulose nanocrystals (CNC). They are often considered as second-generation renewable resources, which also serve as better replacements for petroleum-based products. More attention has been given to these materials because of their low density and high mechanical, renewable, and biodegradable properties. There are many works in the literature on the isolation of NFC and CNC from different sources like hard/soft wood and agriculture biomass. However, this is a comprehensive review dedicated to the properties of NFC and CNC extracted only from agriculture and industrial waste using mechanical, chemical, and enzymatic methods. This article explores in detail the importance of agriculture waste and pretreatments, methods involved in the production of nanocellulose, and the properties of NC prepared from crop and industri...

Importance of Agricultural and Industrial Waste in the Field of Nanocellulose and Recent Industrial Developments of Wood Based Nanocellulose: A Review

This study deals with the tensile drawing behavior of a polylactide material containing 4% of d-stereoisomer units, in the amorphous state. The draw temperature domain spanned from the glass transition to the onset of thermal crystallization, namely 70−100 °C. The stress−strain curves exhibit a strain-hardening strongly sensitive to the draw temperature regarding both the onset and the slope of the phenomenon. A detailed structural investigation reveals that various strain-induced phase changes take place depending on the draw temperature. For Td = 70 °C, a mesomorphic form develops from the strain-oriented amorphous chains, starting at a strain level e ≈ 130%. In the case Td = 90 °C, a well-defined crystalline phase grows beyond the strain e ≈ 250%. In the midtemperature range, i.e. Td = 80 °C, both the mesomorphic and the crystalline phases are generated in parallel. In all cases, the final weight content of ordered phases at rupture was roughly 30%, irrespective of their form. The observed evolution wi...

Strain-Induced Molecular Ordering in Polylactide upon Uniaxial Stretching

Oriented structure and anisotropy properties of polymer blown films: HDPE, LLDPE and LDPE

Physical and mechanical properties of PLA composites reinforced by TiO2 grafted flax fibers

The crystallization behavior and the crystalline structure of nylon6-clay nanocomposites are investigated with regard to the processing conditions and thermal treatment. Microextruded bulk samples as well as blown films are under concern. The often reported nucleating effect of the clay particles is shown to strongly depend on the processing parameters prior to the solidification step, namely, the shear intensity which promotes self-nucleation and the temperature of the melt which regulates the density of these unstable nuclei. The MMT content influences the crystallization kinetics and the crystalline structure via the shear amplification phenomenon which increases the densities of both the shear-induced and the MMT-induced nuclei. The MMT platelets also turned out to hinder the crystal growth. The cooling rate plays a major role on the final crystalline structure by shifting the crystallization temperature in the specific growth range of either the α- or the γ-crystal forms of the nylon6 matrix. Blown f...

Crystallization Kinetics and Crystal Structure of Nylon6-Clay Nanocomposites: Combined Effects of Thermomechanical History, Clay Content, and Cooling Conditions

Saïd Elkoun

Papers

Importance of Agricultural and Industrial Waste in the Field of Nanocellulose and Recent Industrial Developments of Wood Based Nanocellulose: A Review

Strain-Induced Molecular Ordering in Polylactide upon Uniaxial Stretching

Oriented structure and anisotropy properties of polymer blown films: HDPE, LLDPE and LDPE

Physical and mechanical properties of PLA composites reinforced by TiO2 grafted flax fibers

Crystallization Kinetics and Crystal Structure of Nylon6-Clay Nanocomposites: Combined Effects of Thermomechanical History, Clay Content, and Cooling Conditions