Water-Soluble Starch-Based Copolymers Synthesized by Electron Beam Irradiation: Physicochemical and Functional Characterization.

Monica R Nemțanu,Viorica Meltzer,Mirela Brașoveanu,Elena Pincu

doi:10.3390/ma15031061

Abstract

Modification of natural polymers for applications in the treatment of waste and surface waters is a continuous concern of researchers and technologists in close relation to the advantages they provide as related to classical polymeric flocculants. In this work, copolymers of starch-graft-polyacrylamide (St-g-PAM) were synthesized by electron beam irradiation used as the free radical initiator by applying different irradiation doses and dose rates. St-g-PAM loaded with ex situ prepared silver nanoparticles was also synthesized by using an accelerated electron beam. The graft copolymers were characterized by chemical analysis, rheology, and differential scanning calorimetry (DSC). The results showed that the level of grafting (monomer conversion coefficient and residual monomer concentration), intrinsic viscosity and thermal behavior (thermodynamic parameters) were influenced by the irradiation dose, dose rate and presence of silver nanoparticles. The flocculation performances of the synthesized copolymers were also tested on water from the meat industry in experiments at the laboratory level. In the coagulation–flocculation process, the copolymer aqueous solutions showed good efficiency to improve different water quality indicators.

Highlights

Renewable raw materials are increasingly used nowadays due to both the rapid development of society in recent decades and the growing interest in using natural, biodegradable and affordable resources
The characterization through chemical analysis and rheology was performed to point out the grafting level and viscosity, while the functionality as flocculant agents was tested on surface water from the meat industry
A high conversion coefficient reflects a high efficiency of monomer transformation in the polymerization process and a considerable reduction of residual monomer content

Summary

Introduction

Renewable raw materials are increasingly used nowadays due to both the rapid development of society in recent decades and the growing interest in using natural, biodegradable and affordable resources. Typically polymeric in nature, are widely used in the modern processes of potable water and wastewater treatment [8,9,10,11]. They can be traditionally synthesized by chemical reactions [3,12,13] controlled by catalysts and reaction conditions. The use of irradiation techniques (gamma radiation or electron beams) allows high efficiency and control of various processes (i.e., grafting, cross-linking) involved in the synthesis of flocculants, avoiding the use of chemical initiators/catalysts [12,14,15,16] or heating processes, which are undesirable in such syntheses. Cross-linking is another type of reaction that can lead to modification and functionalization of natural polymers by increasing their molecular weight and improving and extending their functionality as flocculants [18]

Objectives

Methods

Results