Low-cost Renewable Resources Research Articles

Development of electromagnetic shielding materials from the conductive blends of polystyrene polyaniline-clay nanocomposite

Electromagnetic interference shielding composite materials were developed from the conductive blends of nanostructured polyaniline-clay composite (PANICN) and Polystyrene (PS) by a one step host matrix assisted emulsion polymerization of anilinium salt of 3-pentadecyl phenol-4-sulphonic acid (3-PDPSA) in clay. 3-PDPSA was derived from cashew nut shell liquid, a low cost renewable resource based product. These blends were characterized using Uv–visible and FT-IR spectroscopy, XRD, electrical conductivity, thermal property, dielectric property and electromagnetic shielding efficiency. The interactions between the primary particles and host matrix were elucidated from the studies made through spectroscopy and rheology. The key finding of the research is that this low cost PANICNPS blend with superior electrical conductivity (7.6 × 10 −1 S/m), excellent thermal stability and EMI SE of 10–20 dB at 8 GHz makes them as a promising candidate for application in EMI shielding and antistatic discharge matrix for the encapsulation of micro electronic devices.

Development of electromagnetic shielding materials from the conductive blends of polyaniline and polyaniline-clay nanocomposite-EVA: Preparation and properties

Electromagnetic interference shielding composite materials were developed from the conductive blends of nanostructured polyaniline (PANI) and polyaniline-clay nanocomposite (PANICN) with ethylene vinyl acetate (EVA) as host matrix. Electrically conducting nanostructured PANI and PANICNs were prepared using amphiphilic dopants, 3-pentadecyl phenol 4-sulphonic acid (3-PDPSA) derived from cashew nut shell liquid, a low cost renewable resource based product and dodecyl benzene sulfonic acid (DBSA). Effects of type and quantity of conductive fillers on the electrical conductivity, mechanical properties, thermal stability, morphology and electromagnetic shielding efficiency were investigated. The presence of exfoliated nanoclay and interaction between the conductive filler–host matrix in conductive films containing PANICNs manifested from the measurement on rheological property. Films with conductive filler (∼15% loading) showed a shielding effectiveness of ∼40–80 dB at 8 GHz which makes these conducting composites potential candidate for the encapsulation as EMI shielding materials for electronic devices.

Organic acid toxicity, tolerance, and production in Escherichia coli biorefining applications

Organic acids are valuable platform chemicals for future biorefining applications. Such applications involve the conversion of low-cost renewable resources to platform sugars, which are then converted to platform chemicals by fermentation and further derivatized to large-volume chemicals through conventional catalytic routes. Organic acids are toxic to many of the microorganisms, such as Escherichia coli, proposed to serve as biorefining platform hosts at concentrations well below what is required for economical production. The toxicity is two-fold including not only pH based growth inhibition but also anion-specific effects on metabolism that also affect growth. E. coli maintain viability at very low pH through several different tolerance mechanisms including but not limited to the use of decarboxylation reactions that consume protons, ion transporters that remove protons, increased expression of known stress genes, and changing membrane composition. The focus of this mini-review is on organic acid toxicity and associated tolerance mechanisms as well as several examples of successful organic acid production processes for E. coli.

The mighty cashew

The generic name ‘cashew’ applies to a tree, its fruit, its nuts, and the family to which it belongs. The tree has been cultivated in tropical countries for close on five hundred years, and from the fruit to the nut to the shell, the cashew is basically edible and useful. Outside the Tropics the tree is perhaps best known for its edible nuts. However of the various natural products of the cashew, it is the caustic, black phenolic oil known as cashew nut shell liquid (CNSL), until recently routinely discarded as a waste product, which has been found to be of most interest, as it can be used in numerous industrial and engineering applications. CNSL is essentially a mixture of phenolics and is a good natural alternative to petrochemically derived phenol. Furthermore CNSL has found uses in areas as diverse as paints, corrosion resistant varnishes, and natural composite materials. The fact that CNSL is also a low cost renewable resource which until recently was thought of as a waste product only adds to its appeal and suggests that an exciting future awaits this fascinating material.

The mighty cashew

The generic name ‘cashew’ applies to a tree, its fruit, its nuts, and the family to which it belongs. The tree has been cultivated in tropical countries for close on five hundred years, and from the fruit to the nut to the shell, the cashew is basically edible and useful. Outside the Tropics the tree is perhaps best known for its edible nuts. However of the various natural products of the cashew, it is the caustic, black phenolic oil known as cashew nut shell liquid (CNSL), until recently routinely discarded as a waste product, which has been found to be of most interest, as it can be used in numerous industrial and engineering applications. CNSL is essentially a mixture of phenolics and is a good natural alternative to petrochemically derived phenol. Furthermore CNSL has found uses in areas as diverse as paints, corrosion resistant varnishes, and natural composite materials. The fact that CNSL is also a low cost renewable resource which until recently was thought of as a waste product only adds to its appeal and suggests that an exciting future awaits this fascinating material.