Effect of grafting with acrylic monomers on the viscosity, gelatinization temperature, and granule swelling characteristics of starch

Abstract

Amylography and scanning electron microscopy (SEM) studies on grafted copolymers of starch with methacrylic acid and methyl methacrylate demonstrated significant changes in the viscosity and granule disintegration characteristics, depending on the extent of grafting and the nature of the monomer. Marked viscosity changes were observed when the carboxyl groups of the starch-graft-poly(methacrylic acid) (SPMAA) were neutralized with sodium hydroxide. The viscosity modification was found to be dependent on the extent of neutralization, and a maximum was observed at 10 -25% neutralization. With an increase in extent of neutralization, there was a decrease in gelatinization temperature. For a sample of SPMAA with a percentage grafting of 14.1, the gelatinization temperature decreased from 64°C for the acid form to 42°C for the fully neutralized form. The gelatinization temperature of the fully neutralized samples of SPMAA showed a linear relationship with the percentage grafting. SEM was used to elucidate the effect of grafting on the granule swelling characteristics of starch at various temperatures. In the case of starch-graft-polymethyl methacrylate (SPMMA), granule disruption on heating with water was observed. However, this did not lead to the build-up of viscosity on gelatinization. This was explained to be caused by the hydrophobic nature of SPMMA.

Swelling, mechanical and mucoadhesion properties of Mt/starch-g-PMAA nanocomposite hydrogels

“…As observed in Table 1, the amount of the G% of S-g-PMAA was found to be 43.6. When this result was compared with previous studies (Athawale and Lele, 1998;Athawale and Rathi, 1999;Aravindakshan and Kumar, 2002;Güçlü et al, 2006), it was observed that this product has a higher value of G% than those studies. In the previous study (Güler, 2011), when the non-gelatinized starch used in the grafting reaction, the amount of G% was found to be 30.9.…”

“…The grafting of the pH-sensitive monomers such as acrylic and methacrylic acid onto starch could result in combined properties such as, biocompatibility, nontoxicity, and higher bioadhesion depending on the hydrogel composition (Moroa, 2001;L.-M. Zhang et al, 2005;Yan et al, 2005;Bravo-Osuna et al, 2008;Pourjavadi et al, 2008;El-Hag Ali and AlArifi, 2009;Saboktakin et al, 2009;Casas et al, 2010;Mahkam, 2010;Maiti et al, 2010;Liu et al, 2011;Saboktakin et al, 2011;Shalviri et al, 2012). There are numerous papers devoted to synthesis, characterization and applications of grafted starch based hydrogels with different structures and properties (Burr et al, 1975;Misra et al, 1980;Hebeish et al, 1988Hebeish et al, , 1998Vazquez et al, 1989;Khalil et al, 1990Khalil et al, , 1993Mostafa, 1995;Abdel-Hafiz, 1997;Athawale and Rathi, 1997;Athawale and Lele, 1998;Moroa, 2001;Aravindakshan and Kumar, 2002;Beliakova et al, 2004;Geresh et al, 2004;Yan et al, 2005;Pourjavadi et al, 2008;Zhang and Zhou, 2008;El-Hag Ali and AlArifi, 2009;Liu et al, 2009;Marinich et al, 2009;Casas et al, 2010;Mostafa et al, 2011;Pathania and Sharma, 2012;Ismai...…”

Effect of some parameters on the synthesis and the physico-chemical properties of new amphiphilic starch-g-copolymers

“…as stabilizers, rheology modifiers, surface modifiers, compatibilizers, fillers, in coatings, as matrices and excipients for specific drug-delivery systems or as new polymeric materials, etc. (Aravindakshan & Kumar, 2002;Castellano, Gurruchaga, & Goni, 1997;Cho & Lee, 2002;Fakhru'l-Razi, Qudsieh, Yunus, Ahmad, & Rahman, 2001;Kaewtatip & Tanrattanakul, 2008;Kumar, Ganure, Subudhi, & Shukla, 2014;Lutfor, Sidik, Haron, Rahman, & Ahmad, 2003;Marinich, Ferero, & Jimenez-Castellanos, 2009).…”

Graft copolymerization of acrylic acid onto hydrolyzed potato starch using various initiators

“…Most commonly, graft polymerization is brought about by free radical addition polymerization. Even though a large number of reports [18]- [24] on graft copolymerization has been published, there is not a comprehensive understanding of the grafting process yet. Table 1 shows the efficiency parameters of hydrolysis and monomer grafting on starch depending on initiator type.…”

“…Increasing the grafting efficiency is an effective way of improving the properties of starch graft copolymers and reducing their preparation costs [18,19]. However, the graft copolymerization of starch with vinyl monomers is always accompanied by the homopolymerization of vinyl monomers as reactants.…”