Starch-based Surface-sizing Agents in Paper Industry:An Overview

Natural starch is an abundant and inexpensive polysaccharide biopolymer that is widely used as a surface-sizing agent in the paper industry.The surface sizing of paper improves its water and abrasion resistance,as well as its physical strength and printing adaptability.However,natural starch presents some disadvantages,such as high viscosity,poor fluidity,poor filmforming properties,and easy coagulation.Therefore,starch is usually modified and blended with various components to achieve better sizing performance.This article reviews approaches for the surface sizing of paper and modification of starch using enzymes or chemical methods,such as oxidation,cationization,and graft copolymerization.This article also discusses the application of starch-based multiphase systems(obtained by blending starch with various components)as surface-sizing agents.

Synthesis and characterization of a starch-based cationic flocculant for microalgae harvesting

A process for making a starch-based cationic flocculant for microalgae harvest was studied and the performance of the flocculant was evaluated.The substituted cationic starch was prepared by reacting corn starch with glycidyltrimethylammonium chloride(GTAC),during which the hydroxyl groups of anhydroglucose units of the starch were partially substituted by the ammonium groups through etherification.The factors affecting degree of substitution(DS),such as reaction temperature and time,catalyst amount,and the water content were investigated and optimal reaction conditions were determined.The relationship between DS and microalgae harvest was determined.A batch of cationic starch with optimal DS was synthesized and used for flocculation experiments.The flocculation experiment results showed that,for the original microalgae concentration(dry weight)of 1 g/L,the cationic starch-based flocculants can harvest over 90%of the microalgae in pH from 5 to 10,with the aggregation and precipitation time of 10 min to 30 min,and the mass ratios of flocculants to microalgae of 1:8-1:18(dry mass ratio).Using starch-based flocculant to harvest microalgae in the effluent is not only efficient,but also nontoxic to the water system,which is very important to the effluent reuse and certain microalgae applications.

Structure evolution of oxygen removal from porous carbon for optimizing supercapacitor performance

The presence of oxygen functional groups is detrimental to the capacitive performance of porous carbon electrode in organic electrolyte. In this regards, hydrogen thermal reduction has been demonstrated effective approach in removing the unstable surface oxygen while maintaining the high porosity of carbon matrix. However, the exact evolution mechanism of various oxygen species during this process, as well as the correlation with electrochemical properties, is still under development. Herein, biomass-based porous carbon is adopted as the model material to trace its structure evolution of oxygen removal under hydrogen thermal reduction process with the temperature range of 400–800 °C. The optimum microstructure with low oxygen content of 0.90% and proper pore size distribution was achieved at 700°C. XPS, TPRMS and Boehm titration results indicate that the oxygen elimination undergoes three distinctive stages(intermolecular dehydration, hydrogenation and decomposition reactions). The optimum microstructure with low oxygen content of 0.90% and proper pore size distribution was achieved at 700 °C. Benefiting from the stable electrochemical interface and the optimized porous structure, the as-obtained HAC-700 exhibit significantly suppressed self-discharge and leak current, with improved cycling stability, which is attributable to the stabilization of electrochemical interface between carbon surface and electrolyte. The result provides insights for rational design of surface chemistry for high-performance carbon electrode towards advanced energy storage.

The Effect of Food Thickeners on the Bitterness and Dissolution of Amlodipine Besilate Powder When Co-Administered with Thickeners to Patients with Dysphagia

Purpose: The present research was performed to evaluate the effect of food thickeners on the bitterness and dissolution of bitter drugs when co-administered to patients with dysphagia. Methods: Amlodipine besilate (AMPB) powder was used as a model drug. Starch- and xanthan gum-based food thickeners were examined, with swallowing-aid jelly as a reference. The line-spread test (LST), texture prolife analysis (TPA) were done firstly. In related to AMPB powder mixed with food thickeners solution, a conventional dissolution test simulating the oral cavity was performed, the amlodipine (AMP) concentration and taste sensor output for dissolved medium versus time profiles were developed. The dissolution test at pH 1.2 and 4.5, representing typical gastric conditions for younger or elderly people, was performed in two kinds of thickener solution and swallowing-aid jelly those were mixed with AMPB powder. Results: LST demonstrated that xanthan gum-based food thickeners fulfilled the requirements for patients with dysphagia but that starch-based food thickeners did not. In TPA, hardness and adhesiveness decreased proportionally as the concentration increased for both kinds of food thickener. Conventional dissolution test simulating oral cavity demonstrated the following bitterness ranking: xanthan gum-based food thickener Conclusion: Although xanthan gum-based food thickeners were successful in masking the bitterness of AMP, they may reduce its bioavailability in humans. The 7.1 and 4.7 (w/v) % starch-based thickener show bitterness inhibition under simulated oral cavity conditions and complete dissolution of AMP under simulated gastric conditions.

The Effect of Food Thickeners on the Bitterness and Dissolution of Amlodipine Besilate Loaded Oral Disintegration Tablets: Assessment of Potential Suitability for Patients with Dysphagia

The purpose of this research was to evaluate the effect of starch- and xanthan gum-based food thickeners on the bitterness and dissolution of amlodipine besilate (AMPB) loaded orally disintegrating tablets (ODT) for potential use with patients with dysphagia. A conventional dissolution test simulating the oral cavity was performed and the taste sensor output of the dissolved sample was evaluated over a 60-seconds period. When four types of AMPB loaded ODTs were tested alone, at 60 seconds, branded product (A) was the least bitter, followed by generic product (B)/generic product (C) which were equal, and finally generic product (D) which was the most bitter. Inhibition of bitterness of AMPB loaded ODTs mixed thickeners, 1.0 (w/v) % xanthan gum-based food thickener solution was significantly strong. The 7.1 (w/v) % and 4.7 (w/v) % starch-based food thickeners solution also effective in bitterness inhibition compared to the 2.4 (w/v) % starch-based food thickener solution. The dissolution test under pH 1.2 in related to 7.1 (w/v) % and 4.7 (w/v) % starch-based thickener contained each of AMPB loaded ODTs were associated with an almost complete amlodipine (AMP) dissolution (almost 90% at 10 minutes), whereas the 1.0, 2.0, 3.0 (w/v) % xanthan gum-based food thickener solution containing AMPB loaded ODTs did not show complete AMP dissolution and there were large variations in the initial dissolution stage. This suggests that a mixture of xanthan gum-based thickener and AMPB loaded ODT poses a risk of reduction of bioavailability. In conclusion, a mixture of 4.7 (w/v) % or 7.1 (w/v) % starch-based thickener with ODTs provides complete release of AMP and superior bitterness inhibition, so is the best choice for administration to patients with dysphagia.

Improvement and optimization of preparation process of seedling-growing bowl tray made of paddy straw

A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTMPS preparation method has been developed by using straw powder as the main raw material.In this method,modified starch-based adhesive was replaced by the binder of thermosetting adhesive,and preparation constraints such as forming pressure,forming temperature,and dwell time were decreased.The effects of factors such as glue(modified starch-based adhesive),forming pressure,forming temperature and dwell time on SGBTMPS preparation were evaluated by single factor experiment.Orthogonal experiment and comprehensive weight analyses were adopted to optimize the parameters for SGBTMPS preparation.The results showed that optimized parameters were 125% glue and 1.2 kg mixed materials with the forming pressure,temperature,and dwell time of 30 MPa,140℃ and 330 seconds,respectively.Compared with traditional preparation process,the proportioning link,preparation link,and preparation time in the new preparation process were reduced by 66.7%,33.3%,and 17%,respectively;the pot-hole percentage and the expansion ratio were increased by 0.09% and 0.05%,respectively.This study indicated that the new preparation process for SGBTMPS was simpler and easier to operate and would provide a useful reference for further research and industrialization on SGBTMPS.

Application of a green coagulant with PACl in efficient purification of turbid water and its mechanism study

The applications of natural polymeric flocculants due to their green feature has been recently received much more attention. In this work, the combined usages of a cationic starch-based coagulant and polyaluminum chloride(PACl) were extensively evaluated for various addition sequences in the coagulation of both raw(surface water from the Jiuxiang River) and synthetic turbid water(two kaolin suspensions with different initial turbidities).Two typical cationic starch-based coagulants with different structures(St-G and St-E) were tried. In comparison to St-G, St-E and PACl used individually as well as St-G and St-E dosed after PACl, the combination of the starch-based coagulants fed before PACl showed higher turbidity removal efficiency, which featured not only less optimal doses of both inorganic and organic coagulants but also lower residual turbidity. On the basis of a detailed analysis of the particle size and its distribution in solution supernatants before and after coagulation by two starch-based coagulants and PACl, polymeric coagulants preferentially coagulate the small-sized colloids due to their distinct long-chain structures, but PACl preferentially coagulates the medium-sized ones. Thus, the medium-sized particles that were previously formed by the starch-based coagulants would be collectively and effectively removed by the subsequent addition of PACl. The addition sequence of the inorganic and organic coagulants in their combined usage is an important factor for improvement of the turbidity removal efficiency in practice.