Synthesis of environmentally-friendly polyurethane dispersions based on soybean oil- derived polyols and their applications in advanced water-based and uv-cure coatings

Polyurethane dispersions (PUD) have established themselves as most versatile polymeric binder in coating, adhesive, sealant, and elastomer industries. Like any other polymers, PUDs also have certain limitations, such as hydrolytic stability, water resistance, and oil resistance. In order to develop these properties, two different polyol families were synthesized. The first polyol can be used in ambient curable systems, and the second can be utilized in ultraviolet radiation cure coatings. For ambient curable systems polyether chemistry based soy-polyol was developed from epoxidized soy fatty acid methyl ester (ESFAME). The cationic ring opening of oxirane oxygen groups from ESFAME resulted in polyol with average hydroxyl number 88 mgKOH/g and number average molecular weight 1517. The indigenous soy-polyol was used as soft segment polymeric chain backbone of aqueous PUD. The PUDs with varying soft segment to hard segment ratios were developed and characterized for film properties, surface properties, chemical resistance, and thermal properties. The PUD (55% bio content) with reasonable aforementioned properties was utilized for further developmental work, where hydrophobicity and oleophobicity of the coatings were improved to meet the goal of the project. Siliconated (Si) and fluorinated (F) polyol was utilized with indigenous soy-polyol, and 7 different polyurethane polymeric chains were fabricated with varying Si and F concentration. The topographical morphologies of these PUDs were monitored with AFM, and the hydrophobicity was monitored with contact angle instrument. All other basic film properties, water and oil resistance properties were thoroughly discussed. Also, the PUDs !! vi! were self-crosslinked with carbodiimide and excellent water resistance and oil resistance coatings were achieved from this research. For ultraviolet curable coatings, novel hydroxylated acrylic epoxidized soybean oil was synthesized from commercially available epoxidized soybean oil (ESO). It was characterized for viscosity, hydroxyl number, iodine number, molecular weight, FT-IR, and NMR studies. The UV-cured coating films were designed from this indigenous acrylated ESO (AESO) and they were tested for pencil hardness, pendulum hardness, impact resistance, adhesion strength, and thermal properties. In order to further improve the mechanical properties, AESO was used in dual curable coatings. The developed instant radiation curable and ambient curable coatings resulted in excellent chemical resistance, optimum mechanical and thermal properties. The advantage of hydroxyl groups of AESO was taken to develop 9 different UV-curable PUDs. The coating properties were characterized based on constant crosslink density, increasing crosslink density. Once again, topographical studies were conducted with AFM, and contact angle studies were used to determine the UV-PUDs water resistance

Status and prospects of cultivation of Garcinia species in India

Garcinia is one of the important genus of family Clusiaceae. There are more than 250 species in this genus. The trees of the genus are evergreen and medium in size. These are distributed in tropical regions, with high species diversity in South Asia and South Eastern Asia. In India, 43 species are found which are distributed in North East India, the Western Ghats and Andaman and Nicobar Islands. Most of these species produces edible fruits and known for their medicinal values. Garcinia provide spice, fruit, medicine, cooking butter, colour and polishing agents for metallic surfaces such as gold and silver. The fruits of the genus contain p-hydroxycitric acid which has inhibitory effect on lipogenesis and helps in controlling obesity in human beings. Most of these species are found in wild but some are cultivated for fruits . Mangosteen, Kokum, Malabar tamarind, yellow mangosteen are some species which are cultivated in India and some region South Eastern Asian countries. The cultivation is these fruits is gaining popularity due to their unique taste and medicinal properties. The status, genetic resources, their production practices and prospects in India is summaries in this article

Geochemical aspects ofMeretrix casta (bivalve) shells of Vellar estuary, southeast coast of India

The bivalve mollusk, Meretrix casta shells are abundant in the Vellar estuary along the East coast of India, they are economically important and used as chief raw material for many lime based industries. Their shells are harvested in large quantities for meat and lime production. The present study focused on understanding the chemical characteristics of M. casta shells, collected at eight different locations in the marine zone of Vellar estuary. Slica, alumina, iron, calcium and magnesium were determined by wet analysis method. The concentrations of Cu, Fe, Zn, Cd, Hg and Mg were analysed by inductive coupled plasma - optical emission spectroscopy (ICP-OES). The M. casta shells consists of calcium which is up to 54%, silica, aluminum, iron and magnesium constituents are very small. Metal concentrations in the shells were in the following order: Fe>Mg>Zn>Cu. The results of heavy metal concentrations was Fe (1.822 mg/l), Mg (0.420 mg/l), Zn (0.026mg/l) and Cu (0.017 mg/l), the elements Cd and Hg were below detection limit in all the eight locations. The result evidenced that the shells were suitable for industrial applications especially for lime based industries. Key words: Raw materials, bivalve, Meretrix casta, ICP-OES, heavy metals, Vellar estuary.African Journal of Biotechnology, Vol 13(19), 2090-209

Hydrogeochemical Characteristics and Evolution of Coastal Groundwater at Cuddalore Area, Tamilnadu, India

ABSTRACT- The hydrogeochemical data of groundwater’s of the different aquifers of the Cuddalore coastal area, Tamilnadu were examined to determine the main factors controlling the groundwater chemistry and salinity as well as its hydrogeochemical evolution. The geology of the area plays a significant role in the determination of the groundwater potential of the region. The area underline by the various geological formations ranging in age from the oldest Archaean rocks to recent sediments. Groundwater of the coastal alluvial aquifer has the highest conductivity values in the study area due to the impact of seawater and agricultural activities. Piper diagram showed that Cl and SO4 are the dominant anions, whereas Na is the most dominant cation, where it is sometimes replaced by Ca and/or Mg in the hydrochemical facies of the ground waters. The paper revealed that the groundwater has been evolved from Ca-HCO3 recharge water through mixing with the pre-existing groundwater to give mixed water of Mg- SO4 and Mg-Cl types that eventually reached a final stage of evolution represented by a Na-Cl water type. Different ionic ratios revealed the impact of seawater and marine aerosols on the hydrochemical composition of groundwater of the Quaternary aquifer. Dissolution of carbonate and sulfate minerals in the aquifer matrices and recharge areas as well as cation exchange are shown to modify the concentration of ions in groundwater. Groundwater-mineral equilibrium showed the prevailing dissolution-precipitation reactions in the groundwater