Starch‐derived glycol and glycerol glucosides prepared by reactive extrusion processing

Abstract

SYNOPSISPreviously, starch-derived glycol and glycerol glucosides were prepared by batch-reaction processes and had excellent potential as chemical intermediates for a wide range of products. However, more efficient processes for preparation of these derivatives are needed. In this present work, a modern corotating, intermeshing, twin-screw extruder with a barrel length/ screw diameter ( L / D ) ratio of 43 : 1 was used to study the reaction of starch with ethylene glycol and glycerol in the presence of sulfuric acid catalyst at elevated temperatures. A fully continuous process was used. Variables that were investigated included temperature ( 14O-18O0C), glycol or glycerol/starch AGU mol ratio (1.5-4.0), starch feed rate (5-30 lb/h) , screw speed ( 100-475 rpm) , residence time, specific energy, and several types of commercial cornstarch and corn flour products. Rates and extents of reaction that occurred in the barrel were determined by analyzing samples that were quenched just prior to extrusion. The major glucosides were quantitated by high-performance liquid chromatography. Results of this study show that starch can be continuously, rapidly, and efficiently converted to glucosides in 90% yield at high production rates. Such processing is expected to be technically feasible for the reaction of a wide range of polyhydroxy alcohols with various starch substrates. However, additional process time, energy consumption, and handling methods are required in the latter procedure.Because twin-screw extruders are well recognized as efficient mixers for handling the most difficult mixing requirements, the reaction of starch with EG in a small twin-screw processor by a semi-continuous process was recently inve~tigated.~ In that study, glucosides were obtained in high yield, but only a t inefficient throughput rates, because of the short barrel and inadequate barrel lengthlscrew diameter ( L / D ) ratio ( 9 : 1) of the processor.For the present work, a corotating, intermeshing, twin-screw extruder with a n L / D ratio of 43 : 1 and 45

In situ compatibilization of maleated thermoplastic starch/polyester melt‐blends by reactive extrusion

“…domains generated by retrogradation of the amorphous chains. Residual A-type crystallinity derived from cornstarch could also be observed in TPS (at $178) [38] (see Fig. 3), though diminished.…”

[No Title Available]

“…Modificación química del almidón por glucosilación y posterior transesterificación con el aceite de ricino original y modificado para obtener los denominados poliol-glucósidos: El almidón de yuca comercial reaccionó con el glicerol [20] , en presencia de ácido sulfúrico como catalizador en una proporción 0.5% peso de catalizador/peso de glicerol. Se utilizó un balón-reactor de cuatro bocas equipado con termómetro, agitador mecánico y entrada de nitrógeno.…”

Recent Advances in Reactive Extrusion Processing of Biodegradable Polymer‐Based Compositions

“…In addition to reduced melt‐viscosity, the interest in using MTPS is the presence of free carboxylic acid groups, i.e. MA moieties grafted onto the starch backbone, which could promote acid transesterification reactions with polyester chains such as PBAT, leading to graft copolymers147–149 (Figure 15). We selected PBAT as a good candidate for melt‐blending with starch‐based products due to its interesting thermal and mechanical properties 138…”