Biocomposites reinforced with natural fibers: 2000–2010

Due to their abundance, high strength and stiffness, low weight and biodegradability, nano-scale cellulose fiber materials (e.g., microfibrillated cellulose and bacterial cellulose) serve as promising candidates for bio-nanocomposite production. Such new high-value materials are the subject of continuing research and are commercially interesting in terms of new products from the pulp and paper industry and the agricultural sector. Cellulose nanofibers can be extracted from various plant sources and, although the mechanical separation of plant fibers into smaller elementary constituents has typically required high energy input, chemical and/or enzymatic fiber pre-treatments have been developed to overcome this problem. A challenge associated with using nanocellulose in composites is the lack of compatibility with hydrophobic polymers and various chemical modification methods have been explored in order to address this hurdle. This review summarizes progress in nanocellulose preparation with a particular focus on microfibrillated cellulose and also discusses recent developments in bio-nanocomposite fabrication based on nanocellulose.

Microfibrillated cellulose and new nanocomposite materials: a review

UV-Visible ار راد ن .د TiO2 ( تیفرظ راون مان هب نورتکلا یاراد یژرنا زارت لماش VB و ) رگید زارت ی یژرنا اب ( ییاناسر راون مان هب نورتکلا زا یلاخ و رتلااب VB یم ) .دشاب ت ود نیا نیب یژرنا توافت یژرنا فاکش زار ، پگ دناب هدیمان یم .دوش هک ینامز زا نورتکلا لاقتنا VB هب VB یم ماجنا دریگ ، TiO2 اب ودح یژرنا بذج د ev 2 / 3 ، نورتکلا تفج کی دیلوت یم هرفح .دیامن و نورتکلا هرفح ی نا اب هدش دیلوت یم کرتشم حطس هب لاقت ثعاب دناوت شنکاو ماجنا اه یی ددرگ . TiO2 دربراک ،دراد یدایز یاه هلمج زا یم ناوت اوه یگدولآ هیفصت یارب (CO2) و بآ و ... نآ زا هدافتسا درک .

Advanced Nanoarchitectures for Solar Photocatalytic Applications

1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

Advanced functional polymer membranes

Surface silylation of cellulose microfibrils: preparation and rheological properties

Polypropylene/graphene nanosheet nanocomposites by in situ polymerization: Synthesis, characterization and fundamental properties

The competition between α, β, and γ polymorphs has been studied in a β-nucleated metallocenic isotactic polypropylene, iPP, as a function of the cooling rate and of the isothermal crystallization temperature, by performing X-ray diffraction and DSC experiments. It was found that the addition of a 1% by weight of a typical β-nucleating agent is not enough to develop any appreciable amount of β modification, at least under the crystallization conditions used, which cover a wide range of cooling rates. In comparison, the same amount of nucleating agent added to a Ziegler−Natta iPP leads to almost 100% of β form at low cooling rates. It seems that such amount of β nucleating agent is not enough to counterbalance the well-known γ nucleation ability of the relatively high content of defects (stereo- and regioerrors) which are present in the studied metallocenic iPP, and only different proportions of γ and α modifications are obtained in this sample, the relative amount of them depending on the cooling rate. On ...

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Competition between α, β, and γ Polymorphs in a β-Nucleated Metallocenic Isotactic Polypropylene

The incorporation of TiO2 nanoparticles into (ethylene-vinyl alcohol)-based food packaging copolymers affords an opportunity to synthesize polymer-based nanocomposite materials with novel and powerful biocidal and photodegradability properties, resulting in the production of an advanced, environmentally friendly system prepared using a cost-effective synthesis method via a simple melt compounding without the need of a coupling agent incorporation. The presented materials display an unprecedented performance in the killing of both Gram positive and negative bacteria without the necessity of being release to the media and an easy degradation under sunlight which favorably competes with biodegradation procedures.

High-Performance Dual-Action Polymer -TiO2 Nanocomposite Films via Melting Processing

Nanocomposite materials obtained by TiO 2 incorporation into ethylene-vinyl alcohol copolymers, extensively used in food packaging, are prepared via a straightforward melting process. The structural characteristics of the nanocomposites are examined using wide and small angle X-ray scattering (WAXS/SAXS), and vibrational infrared and Raman spectroscopies. A microscopy (SEM/TEM) study shows that the materials obtained are highly homogeneous at the nanometric scale, exhibiting an intimate contact between both the organic and inorganic components. TiO 2 incorporation into this polymer matrix renders self-sterilized nanocomposite materials upon light excitation, which are tested against nine micro-organisms (gram-positive and gram-negative bacteria, cocci, and yeasts) typically involved in food contamination and/or degradation. Overall, the nanocomposites display an impressive performance in the killing of all micro-organisms with a maximum for an oxide content between 2-5 wt %. The measurement of the physico-chemical properties together with the structural characterization of the materials provide conclusive evidence that the nanocomposites biocidal capability born of the nanometric organo-inorganic interface and rationalize the existence of a maximum as a function of the TiO 2 content.

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María L. Cerrada

Papers

Surface silylation of cellulose microfibrils: preparation and rheological properties

Polypropylene/graphene nanosheet nanocomposites by in situ polymerization: Synthesis, characterization and fundamental properties

Competition between α, β, and γ Polymorphs in a β-Nucleated Metallocenic Isotactic Polypropylene

High-Performance Dual-Action Polymer -TiO2 Nanocomposite Films via Melting Processing

Self‐Sterilized EVOH‐TiO2 Nanocomposites: Interface Effects on Biocidal Properties