Rheological behavior of reaction mixtures during the graft copolymerization of cassava starch with acrylic acid

Abstract

Literature data on the rheological behavior of a reaction mixture during the graft copolymerization of acrylic acid onto gelatinized starch are scarce. Yet, such information is important for process design. In this work, continuous torque recording was found to be a suitable method to monitor the apparent viscosity. Reactions were performed in a bench scale reactor at ambient conditions with the monomer to starch ratio as the main variable. Apparent viscosity of the reaction mixture increased rapidly, which could be fitted with good accuracy with a first order exponential growth model. The maximum viscosity of 18 Pa⋅s was seen at the intermediate monomer to starch ratio of 1.0, a phenomenon that is in accordance with literature data. Starch thixotropy is influenced by the grafting of poly‐acrylic acid, until it has almost disappeared at the highest monomer to starch molar ratio of 2.0. POLYM. ENG. SCI., 57:1285–1292, 2017. © 2017 Society of Plastics Engineers

Rheokinetics of graft copolymerization of acrylamide in concentrated starch and rheological behaviors and microstructures of reaction products

“…Traditionally, a static mixer (torque rheometer) with a torque that is monitored has usually been used to study the rheokinetics of reaction systems with high viscosities. In particular, for polymer melts, the reaction between the polymer chains is usually controlled by the diffusion rate of mass transfer rather than the kinetics of chemical bonding mechanisms (Witono, Noordergraaf, Heeres, & Janssen, 2017;Zhou, Yu, & Zhou, 2009). However, a static mixer may not be suitable for studying all the reactions.…”

Preparation and Barrier Performance of Layer-Modified Soil-Stripping/Cassava Starch Composite Films

“…After organic modification, the molecular agglomerates become smaller, indicating that the modifier could effectively enter the interlayer structure and react with the cations of the montmorillonite, thus reducing its agglomeration. The plane-view SEM image of the organic montmorillonite/starch film ( Figure 2 c) shows that the organic montmorillonite has a three-layered structure that can support a stable layered structure after binding with starch [ 18 ]. The organic montmorillonite supports the increasing or decreasing distance of the montmorillonite layers and the starch can be fully combined with montmorillonite.…”

Torque Measurement as a Tool to Monitor the Breakdown of Cassava Starch Gels, by the Effect of Fenton's Initiator for Graft Copolymerization

“…Starch reactions with Fenton's were performed in a stainless steel batch reactor of 500 ml content, fitted with a water jacket to control reaction temperature. The set up was equipped with a Heidolph RZR 2102 control combined stirrer-torque meter as reported in previous work [1,24]. Fig.…”

“…In previous work, torque measurement was successfully applied to monitor the viscosity of a gel during the graft copolymerization of acrylic acid onto cassava starch [24], which was recognized as a step forward in experimental monitoring of reactions [25]. In the present paper, an experimental study is reported applying this torque measurement method also as a tool to explore the effect of Fenton's initiator on the integrity of cassava starch gel.…”

“…In these experiments, the use of NaOH to assist the gelatinization of potato starch may also have caused some chain degradation. Also, the high stirring speed applied in those early experiments (700 rpm) may enhance the contribution of starch viscosity decrease by thixotropic effects [24,25], a physical effect. Despite that, the conclusion from the results from Table 1 is similar to the findings of Fanta et al [21] with wheat starch and Hsu et al [22] with chitosan.…”