Impact of Poly (Ethylene Glycol)(PEG) Concentrations in Poly styrene Blends as Anti-algal Substance against Green Micro-Algae

Abstract

Algal Bio-fouling is one of the most important global issues that negatively effects diverse fields mainly food preservation, water purification, marine industry, heat exchangers, photo bioreactors, biomedical implants etc. There is a wide variety of different techniques and material systems employed to either inhibit the microbial growth or disinfect the underline biofilm. Among various anti-fouling materials polymers have gain special interest due to their economical availability, processing ease and efficient growth inhibition of microbial films. They can be used in a wide variety of forms including copolymers, blends, coatings, polymer brushes, grafted polymers etc. Poly (ethylene glycol) (PEG) is one of the efficient anti-fouling materials. In present study Poly (ethylene glycol) (PEG-1000) and Silver sulfadiazine (SS) are blended as anti-algal agents with Polystyrene (PS) in different weight concentrations. The weight concentration of PEG was varied from 5% to 20% in binary PEG and PS based blends. The specific blend of PS and SS was composed of 10% SS. There was also one ternary blend composed of PS, PEG and SS in which PEG and SS were used 10% each. The synthesis of various polymer blends was done through Extrusion Plastometer at 210C° and using 10kg load. The anti-algal behavior of polymer blends was studied through agar disk diffusion method against three different algal strains namely Dictyosphaerium sp. Strain HM1 (DHM1), Dictyosphaerium sp. Strain HM2 (DHM2) and Pectinodesmus sp. Strain HM3 (PHM3). The algal growth inhibition factors with respect to diameter IAD (a) and area IAD (b) were then calculated and plotted corresponding to various samples. The IAD (a) factor increased from zero to maximum value of 8.3mm for ternary blend of PEG, SS and PS. The IAD (b) parameter managed to increase from zero to 343.2mm2 for the same sample. The results indicate that both PEG and SS based blends are effective against all the three algal strains. The synergetic effect of PEG and SS was exceptional as far as anti-algal properties are concerned. The algal growth inhibition was found to increase with the increase in amount of anti-algal agent. The samples were then characterized through other techniques like mechanical testing, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and zeta-potential (ZP). Mechanical testing was done to study the tensile properties like tensile strength, percentage elongation and elastic modulus of various samples. DSC and TGA were employed to analyze the thermal transitions and thermal stability of blends v respectively. The purpose of zeta-potential (ZP) measurement was to calculate the zeta potential and particle size of algal strains which are extremely significant parameters to design certain anti-fouling system. The results proved the anti-algal behavior of PEG and SS based Polystyrene blends with excellent thermal and mechanical profile which can be used for a wide variety of applications.