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American Society for Testing and Materials

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

Green composites from sustainable cellulose nanofibrils: A review

Responsive polymers in controlled drug delivery

Mechanical, thermal and morphological characterization of recycled LDPE/corn starch blends

The sisal (Agave sisalana) is a cellulosic fiber produced in Brazil since 1903 and until now has been one of the most traded due to its characteristics such as the low cost, low density, specific resistance, biological degradability, CO2 neutrality, renewability, good mechanical properties, non-toxicity and furthermore can be easily modified by a chemical agent improving their mechanical and thermal properties. In this work, the sisal fibers were modified by alkali solutions of NaOH (5% and 10%) and bleached with sodium hyplochlorite NaClO/H2O (1:1) at 60–75 °C. It was used as reinforcing agent in the preparation of phenolic matrix composites derived from cashew nut shell liquid (CNSL). The chemical treatment improved the thermal stability of the weight loss process for sisal treated with NaOH 5% in about 12 °C and for sisal treated with NaOH 10% in about 18 °C when compared to sisal fiber in its raw state. It was also observed a variation of 15 °C when comparing the composite reinforced by raw sisal with composite reinforced with sisal treated NaOH 10%.

Properties of sisal fibers treated by alkali solution and their application into cardanol-based biocomposites

Influence of poly (ethylene glycol) on the thermal, mechanical, morphological, physical-chemical and biodegradation properties of poly (3-hydroxybutyrate)

Development of a biodegradable polymer electrolyte for rechargeable batteries

Current challenges highlight the need for polymer research using renewable natural sources as a substitute for pe- troleum-based polymers. The use of polyols obtained from renewable sources combined with the reuse of industrial residues such as lignin is an important agent in this process. Different compositions of polyurethane-type materials were prepared by combining technical Kraft lignin (TKL) with castor oil (CO) or modified castor oil (MCO1 and MCO2) to increase their re- activity towards diphenylmethane diisocyanate (MDI). The results indicate that lignin increases the glass transition temper- ature, the crosslinking density and improves the ultimate stress especially for those prepared from MCO2 and 30% lignin content from 8.2 MPa (lignin free) to 23.5 MPa. Scanning electron microscopy (SEM) micrographs of rupture surface after uniaxial tensile tests show ductile-to-brittle transition. The results show the possibility to develop polyurethane-type materials, varying technical grade Kraft lignin content, which cover a wide range of mechanical properties (from large elastic/low Young modulus to brittle/high Young modulus polyurethanes).

http://www.expresspolymlett.com/letolt.php?file=EPL-0007327&mi=c

Derval dos Santos Rosa

Papers

Mechanical, thermal and morphological characterization of recycled LDPE/corn starch blends

Properties of sisal fibers treated by alkali solution and their application into cardanol-based biocomposites

Influence of poly (ethylene glycol) on the thermal, mechanical, morphological, physical-chemical and biodegradation properties of poly (3-hydroxybutyrate)

Development of a biodegradable polymer electrolyte for rechargeable batteries

Bio-based polyurethane prepared from Kraft lignin and modified castor oil