A Primary Method for the Determination of Hydroxyl Value of Polyols by Fourier Transform Mid-Infrared Spectroscopy

A primary Fourier transform infrared (FTIR) method was developed to determine the hydroxyl value (OHV) of polyols produced from edible oils. The method is a modification of American Society for Testing and Materials 1899‐08, using toluene as the solvent to dissolve the sample and to carry the reactive reagent p‐toluenesulfonyl isocyanate (TSI). TSI reacts with OH groups to produce a carbamate, a functional group that can be measured spectrally between ~1780 and 1690 cm^?1 in the differential spectrum that is obtained from spectra collected before and after the reaction. Commercially available 1‐nonanol, which has a defined OHV, is used to develop a calibration. The OHV for a variety of 1° and 2° alcohols, as well as petrochemical and lipid‐based polyols, were then measured to evaluate the performance of the method and to assess the effects of moisture on the results. The FTIR OHV were in accord with the results obtained by AOCS method Cd 13‐60 and were demonstrated to be unaffected by the presence of moisture in the sample. The new TSI‐FTIR method is simpler, much faster (~10 min), and more reproducible and accurate than the AOCS OHV titrimetric methods and is not affected by carboxylic acids, amines or moisture.     

Removal of Alkaline Catalysts from Polyols by Ion Exchange

Abstract

Resin regeneration is crucial in the feasibility of polyol purification by ion exchange. In order to get an economically viable commercial process, a new regeneration process, including initial and final methanol flushing steps and treating with a 4.5 M aqueous mineral acid solution, has been investigated. An important reduction in regeneration costs was reached by minimizing the amount of acid used and recycling one part of the regenerant solution to the process. The composition of regeneration effluents has been studied in order to recover their valuable components. This simple resin regeneration technique lends itself to a technically and economically viable commercial process for the treatment of polyol products.     

立式自动压滤机在变性淀粉与糖醇生产中的应用

采用进口立式自动压滤机在湿法变性淀粉生产中替代碟片分离机与卧式刮刀离心机组合，在糖醇生产的结晶工艺中替代离心分离机，取得了良好的效果。本文对两种工艺的分离、洗涤、脱水及节能效果进行了比较。     

The Stabilizing Effects of Polyols and Sugars on Porcine Pancreatic Lipase

Porcine pancreatic lipase (PPL) has been used as a biocatalyst for many years and is one of the most widely used enzymes for biotechnological applications; however, it is a rather complex mixture with various active enzymes. The present study has been undertaken to determine the effects of polyols and sugars (cosolvents) on the thermal stability of PPL preparation. The thermal stability of PPL exposed to 60°C for 10 min was enhanced in the presence of cosolvents in terms of both residual specific activity and conformational stability. Thermal denaturation, changes in circular dichroism, fluorescence spectra, apparent kinetic parameters, activity, and preferential interaction parameter of PPL preparation are discussed in terms of contributions to the mechanism of thermal stability and the activity enhancement. Partial specific volume measurement of PPL in the presence of cosolvents is presented for the first time. The preferential interaction parameter (ξ ₃) was negative in all cosolvents used, and maximum hydration was observed in the presence of trehalose, where the preferential interaction parameter was −0.076 g/g. The observed increase in the thermal stability of PPL preparation in the presence of cosolvents is due to the preferential hydration of the enzyme.     

Evaluation of mannitol and xylitol on the quality of wheat flour and extruded flour products

Effects of polyols (mannitol and xylitol) on physical properties, pasting properties and dynamic rheological properties of wheat flour and the microstructure, water activity (A_w), radial expansion ratio (ER), oil absorption rate (OAR) and texture of extruded flour products were evaluated in this work. The results show that both mannitol and xylitol can promote gluten network formation, enhance tensile resistance and increase the storage modulus (G') and loss modulus (G'') of the dough. More dense and uniform particles were also found on the surface of extruded flour products in the presence of polyols by scanning electron microscopy (SEM). Furthermore, the A_w, hardness and chewiness were reduced while the ER and ORA were increased for extruded flour products by incorporation of polyols. Thus, the extruded flour products with improved quality by polyols exhibit great application prospect in food industry.     

聚醚多元醇官能度的计算与测定

介绍了聚醚多元醇“官能度”的意义、计算、应用与测定,并举出实例加以说明,还给出了若干样品的实测结果。     

PROPERTIES OF UV-CURED POLYURETHANE ACRYLATES: EFFECT OF POLYOL TYPE AND MOLECULAR WEIGHT

Several families of UV-cured polyurethane acrylates were synthesized and the effects of polyol type and molecular weight on their physical properties were investigated. Increasing polyol molecular weight led to a lower polyol glass transition temperature, a smaller amount of a separate urethane acrylate phase, and a larger chain length between crosslinks. The first two effects were reflected in lower modulus and strength at room temperature while the larger chain length between crosslinks led to higher elongation at break (room temperature) and lower modulus at high temperatures. The use of different polyols (polycarbonate, polytetramethylene oxide, polypropylene oxide, and polycaprolactone) primarily affected the room temperature modulus due to differences in the position and breadth of the polyol glass transition. The properties of materials based on isocyanatoethyl methacrylate (IEM) and toluene diisocyanate-2-hydroxyethyl melhacrylate (TDI-HEMA) were also compared.     

A Spectroscopic Method for Hydroxyl Value Determination of Polyols

A relatively simple method is described for routine determination of hydroxyl values for a wide range of hydroxyl containing compounds including soybean oil polyols, polyols derived from soy meal, polyether polyols and ethylene glycol as well as their blends. This method is based on reacting the hydroxyl compound with hexamethyldisilazane (HMDS) and determining the FTIR peak area of the silylated product at 1,251 cm^?1. The method is simple, accurate and reproducible. It is not limited to a specific family of polyol compounds. It does not require any special equipment, hazardous chemicals and can be carried out by non‐technical staff as a rapid and convenient method for quantitative determination of hydroxyl values. An excellent linear correlation was obtained between this spectroscopic method and conventional titration methods for different polyols over a wide range of hydroxyl values. Furthermore, unlike the titration methods the current method is not affected by the presence of acid, base or small amounts of water in the test sample.     

Plant oil polyol based poly (ester urethane) metallohybrid coatings

Research efforts are being focused to develop polymers from bioresources such as plant oils from ecological and economical viewpoints, both in academic research and chemical industry worldwide. Plant oil polymers, their organic-inorganic hybrids and composites find versatile applications today. In the present work, we have reported the preparation and characterization of linseed oil based poly (ester urethane) metallohybrids [PEUMH] from linseed oil polyol [LPO], phthalic anhydride [PAN], toluylene-2,4-diisocyanate [TDI] as organic and copper (II) acetate [Cu-Ac] (in different amount) as inorganic precursors, respectively, in “one-pot, multi-step” reaction. PEUMH were characterized by spectral, physico-chemical, thermal (TGA and DSC) and morphological analyses by standard methods. The potentiality of the same as promising coating material was also evaluated. PEUMH are foreseen as prospective candidates for application as antibacterial self-sterilizing protective coatings due to oligodynamic effect of metal.