Hydroxyalkylation of barbituric acid. II. Synthesis of polyetherols with pyrimidine ring

The route of synthesis of new polyetherols with pyrimidine ring from barbituric acid (BA) was presented. The polyetherols were obtained in two steps: synthesis of hydroxymethyl derivative of BA followed by reaction of the latter with neat ethylene or propylene oxides. Physical properties of the products and preliminary application for fabrication of thermal stability polyurethane foams were determined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Reactions of hydroxymethyl derivatives of uric acid with oxiranes. I. Synthesis of polyetherols with purine rings

Preliminary results on the utilization of uric acid in the synthesis of a new group of polyetherols with purine rings are presented. The polyetherols were prepared in a two‐stage process. First, hydroxymethyl derivatives of uric acid were obtained from an uric acid and formaldehyde solution. This intermediate was then reacted with ethylene oxide or propylene oxide without any additional solvent. The structure of the intermediates and polyetherols and some of their physical properties were determined, and the possibilities of application of the polyetherols in manufacturing thermostable polyurethane foams were tested. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2667–2677, 2000     

New foamed plastic based on polyetherols obtained from 6‐aminouracil,ethylene carbonate,and propylene oxide

Polyetherols with 1,3‐pyrimidine ring including both oxyethylene and oxypropylene groups were obtained in reactions of 6‐aminouracil with ethylene carbonate and propylene oxide. The structure of the products was analyzed by spectral methods. Some physical properties of polyetherols were investigated. The polyetherols were used as polyol components to obtain polyurethane foams. Some properties of the foams such as apparent density, absorption of water, linear dimensions stability, thermal resistance, and compression strength were investigated. The foams obtained show an improved thermal stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polyurethane foams with 1,3‐pyrimidine ring

Attempts of obtaining of polyurethane foams using polyetherols with 1,3‐pyrimidine ring (obtained in reactions of 6‐aminouracil with oxiranes) are reported. Properties of the foams are investigated, especially their thermal stability. The foams show an improved thermal stability up to 200°C for a long time. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polyurethane Foams of Improved Thermal Stability

In reactions of polyetherols prepared from hydroxymethyl derivatives of uric acid and typical oxiranes with isocyanates and water one obtains a new group of polyurethane foams containing purine rings in their structure. These polyurethanes withstand prolonged heating at temperatures as high as 200 °C. Preliminary results on the effect of the type of polyetherol and the composition used in preparation of the polyurethane foams on their properties are presented. The results of studies on thermal stability and mechanical properties of the foams before and after thermal treatment are also reported.

     

Synthesis and studies of phosphorus-containing polyurethane foams based on tetrakis(hydroxymethyl) phosphonium chloride derivatives

A phosphorus- and nitrogen-containing polyl is prepared by condensing tetrakis(hydroxymethyl)phosphonium chloride with diethanol amine in aqueous medium. The newly synthesized polyol-bis(hydroxymethyl)-N, N-bis(2-hydroxyethyl)aminomethylphosphine oxide (AMPO) is used in the preparation of rigid polyurethane foams with a various phosphorus content. With the view to comparing their properties, polyurethane foams are also prepared on the basis of the commercially available flame retardant diethyl-N, N-bis(2-hydroxyethyl)aminomethylphosphonate (Fyrol 6). The flammability, thermal stability, and thermoechanical properties of the polyurethane foams obtained are studied. A certain difference in the behavior of the two modified polyurethane foams is observed. The polyurethane foams with AMPO exhibit a slight increase in the resistance to combustion (oxygen index) and a noticeable improvement in the thermal and mechanical properties. These differences probably arise as a result of structural and functional differences between the two types of phosphorus-containing flame retardants.     

Preparation and characterization of water‐blown polyurethane foams from liquefied cornstalk polyol

Polyurethane foams were prepared from the liquefied cornstalk polyol, which was obtained by the liquefaction of cornstalk in the presence of polyhydric alcohols using sulfuric acid as catalyst. The advisable liquefaction reaction conditions were selected by investigating their influences on the properties of liquefied cornstalk polyol, taking account of the requirement for the preparation of appropriate polyurethane foams. The influences of the contents of catalysts, water, surfactant, and isocyanate on the properties of polyurethane foams were also discussed, and feasible formulations for preparing cornstalk‐based polyurethane foams were proposed. The results indicated that the foams prepared from such liquefied cornstalk polyol exhibited excellent mechanical properties and thermal properties, and could be used as heat‐insulating materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and applications of oligoetherols with perhydro‐1,3,5‐triazine ring and boron

A new method of preparation of oligoetherols containing perhydro‐1,3,5‐triazine rings and boron atoms is presented. The oligoetherols were obtained in the reaction of 1,3,5‐tris(2‐hydroxyethyl) isocyanurate with boric acid followed by reaction with alkylene carbonates. The structure and physical properties of the products render them good candidate for preparing the polyurethane foams. The foams were obtained and their properties were compared with those synthesized from isocyanuric acid and alkylene carbonates. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

New compounds for production of polyurethane foams

A method of boroorganic compound preparation with boric acid, 1,3‐propanediol, 2,3‐butanediol, and 1,4‐butanediol is described in this article. The obtained compounds were characterized with respect to their usability as polyol components for the production of polyurethane (PUR) foams. New boroorganic compounds were applied as polyol components for the foaming of rigid PUR–polyisocyanurate (PIR) foams. The method of preparation, foaming parameters, and physicochemical properties of the PUR–PIR foams and their results are presented. Application of the prepared borates as polyol components in the production of foams had a favorable effect on the properties of the foams. The obtained rigid foams were characterized by lower brittleness, higher compressive strength, content of closed cells, and considerably reduced flammability in comparison with standard foams. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5918–5926, 2006     

Mechanical characterization of phenolic foams modified by short glass fibers and polyurethane prepolymer

Short glass fibers and polyurethane prepolymer were used to modify phenolic foams. The mechanical properties of the composites were characterized and compared with those of foams unmodified and modified with only polyurethane prepolymer or short glass fibers in terms of friability, compression, and bending properties. It shows that polyurethane prepolymer significantly improved the toughness and reduced the friability of phenolic foams, while short glass fibers markedly increased the compression and bending properties. The compound modified foams exhibited significantly lower friability and higher resistance to cracking behavior than conventional phenolic foams and the foams modified with only short glass fibers, and were much stiffer and stronger than conventional phenolic foams and the foams modified with only polyurethane prepolymer. The compound modified phenolic foams with the 1:3 ratio of short glass fibers to polyurethane prepolymer exhibited excellent integrated mechanical properties. POLYM. COMPOS., 36:1584–1589, 2015. © 2014 Society of Plastics Engineers     

Preparation and characterization of rigid polyurethane foams with carbamide and borate groups

The results of research on the application of hydroxyethyl urea derivatives modified with boron as polyol components to produce foamed polyurethane materials are presented. The obtained rigid polyurethane foams are characterized by good heat‐insulating parameters and decreased flammability. The decrease in flammability of the foams follows from the presence of boron and increased nitrogen content, resulting from the use of polyol with urea groups. The incorporation of boron into the foam structure also results in a substantial increase in the compression strength, compared to classic foams and to non‐boron‐modified ones. The self‐extinguishing foams of high mechanical strength can find application as heat‐insulating construction elements for the building industry. © 2016 Society of Chemical Industry     

增强PUR-R泡沫塑料力学性能的测试和讨论

对硬质聚氨酯（PUR－R）泡沫塑料（纯的和增强的）进行了多种力学性能的测试和讨论，给出了实验结果和实用的关系式。纯PUR－R泡沫塑料的力学性能随密度的增大而显著提高；添加增强材料短切玻璃纤维和玻璃微珠可有效地提高PUR－R泡沫塑料的力学性能，综合来看，短切玻璃纤维增强效果不如玻璃微珠，质量分数为10％的玻璃微珠增强效果最好。     

Biodegradable polyurethane foam from liquefied waste paper and its thermal stability,biodegradability, and genotoxicity

Liquefaction of waste paper (WP) was conducted in the presence of polyhydric alcohols to prepare biodegradable polyurethane foam. The liquefied‐WP‐based polyol had suitable characteristics such as apparent molecular weight, hydroxyl value, and viscosity for the preparation of rigid polyurethane foam and was successfully applied to produce polyurethane foam with the appropriate combinations of foaming agents. The obtained foams showed satisfactory densities and mechanical properties as good as those of foams obtained from liquefied wood‐ and starch‐based polyols. The foams had almost the same thermal stability at initial weight loss and seemed to be potentially biodegradable because they were degraded to some extent in leaf mold. There were no mutagens or carcinogens in the water extracts of the foams. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1482–1489, 2002     

Hydroxyalkoxy derivatives of oxamic acid: polyol substrates for polyurethane foams

BACKGROUND: The work reported aimed at obtaining hydroxyalkoxy derivatives containing oxalamidoester groups starting from oxamic acid (OA) substrate. These derivatives were then used for the synthesis of polyurethane foams. RESULTS: The hydroxyalkoxy derivatives were obtained by reaction of OA with 6 to 15 molar excess of ethylene carbonate (1,3‐dioxolane‐2‐one) or propylene carbonate (4‐methyl‐1,3‐dioxolane‐2‐one). The products obtained have good thermal stability and possess suitable physical properties for use as substrates for foamed polyurethanes. CONCLUSION: The rigid polyurethane foams obtained from the hydroxyalkoxy derivatives of OA possess enhanced thermal stability and good mechanical properties in comparison with traditional polyurethane foams. Copyright © 2009 Society of Chemical Industry     

Synthesis of rigid polyurethane foams from oligoester alcohols obtained from dimethyl terephthalate production wastes

A study was conducted to synthesize oligoester alcohols from dimethyl terephthalate production wastes via transesterification with diethylene glycol and trimethylol propane. The oligoester alcohols obtained are suitable for preparing rigid polyurethane foams. The oligoester alcohols from trimethylol propane possess good physical and mechanical properties. The oxygen indices indicate that the polyurethane foams exhibit improved resistance to combustion due to the increased content of aromatic nuclei in the oligoester alcohols.     

Effect of Talc Filler on Physical Properties of Polyurethane Rigid Foams

This article reports on the properties of polyurethane rigid foams, which are used as insulating materials. Most polyurethane rigid foams, derived from cellular polymers, are unstable and tend to crack when acted upon by external forces. These foams are classified as a subgroup of cellular polymers, and thus their low stabilization levels can be partly explained by the fact that they contain cells. In these experiments, we attempted to add talc, to polyurethane rigid foams, as a filler, in an attempt to investigate its effect on the physical properties of the constructed foams in both horizontal and vertical directions. Physical and comparative tests were performed on various compositions of polyurethane foam to chart their insulating capabilities, and our comparative analysis indicated that advances had been achieved with respect to some of its properties.     

Reinforcement of soy polyol‐based rigid polyurethane foams by cellulose microfibers and nanoclays

Water‐blown rigid polyurethane foams from soy‐based polyol were prepared and their structure–property correlations investigated. Cellulose microfibers and nanoclays were added to the formulations to investigate their effect on morphology, mechanical, and thermal properties of polyurethane foams. Physical properties of foams, including density and compressive strength, were determined. The cellular morphologies of foams were analyzed by SEM and X‐ray micro‐CT and revealed that incorporation of microfibers and nanoclays into foam altered the cellular structure of the foams. Average cell size decreased, cell size distribution narrowed and number fractions of small cells increased with the incorporation of microfibers and nanoclays into the foam, thereby altering the foam mechanical properties. The morphology and properties of nanoclay reinforced polyurethane foams were also found to be dependent on the functional groups of the organic modifiers. Results showed that the compressive strengths of rigid foams were increased by addition of cellulose microfibers or nanoclays into the foams. Thermogravimetric analysis (TGA) was used to characterize the thermal decomposition properties of the foams. The thermal decomposition behavior of all soy‐based polyurethane foams was a three‐step process and while the addition of cellulose microfibers delayed the onset of degradation, incorporation of nanoclays seemed to have no significant influence on the thermal degradation properties of the foams as compared to the foams without reinforcements. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Water-absorbing polyurethane foams from liquefied starch

Water-absorbing polyurethane foams were prepared from liquefied starch polyols and diphenylmathane diisocyanate (MDI) by using a cell-opening foaming surfactant. The liquefied starch polyols were obtained by the liquefactions of starch in the presence of polyethylene glycol-dominant reaction reagents by using sulfuric acid as a catalyst under either a refluxing condition or a reduced-pressure condition. The influences of the liquefaction conditions on the properties of the liquefied starch polyols were investigated, taking into account the requirements for preparing appropriate polyurethane foam. Feasible formulations for the preparation of the water-absorbing foams were proposed and the properties of the foams obtained were investigated. © 1996 John Wiley & Sons, Inc.     

Characterization of polyurethane foams prepared from liquefied sawdust by crude glycerol and polyethylene glycol

The aim of this study was to investigate polyurethane foams (PUF) properties obtained from crude glycerol (CG) and polyethylene glycol (PEG) based liquefaction of sawdust. The four types of foam were prepared by producing polyols from different weight loadings of PEG to CG as the liquefaction solvent. The produced polyurethane foams showed densities from 0.042 to 0.08 g/cm³ and compressive strengths from 200 to 311 kPa. The foams obtained from CG/PEG based liquefaction, had more uniform and regular cell structure than foams derived from liquefaction by CG. Also with the increasing percentage of PEG to CG in liquefaction, closed cell content of the synthesized foams increased and the size of cells decreased. The thermal conductivity of the produced foams was between 0.031 and 0.040 W/m K. Foams produced from liquefaction by binary solvent had lower thermal conductivity. However all foams showed approximately similar thermal degradation curves; maximum thermal decomposition temperature was seen for the foam produced from higher weight ratio of PEG to CG in liquefaction. PU foams produced from PEG/CG based liquefaction process had improved properties over from foams derived from sawdust liquefaction by CG.     

脂肪族聚碳酸酯型聚氨酯软泡性能的影响因素

以自制的脂肪族聚碳酸亚乙酯二元醇和液化MDI为主要原料,制备了聚碳酸酯型聚氨酯软泡,并对发泡剂、异氰酸酯、稳定剂用量及操作工艺等对泡沫体性能的影响进行了讨论。结果表明,通过调节发泡剂、异氰酸酯、稳定剂用量等,可以得到密度在8~80kg/m3之间、压缩强度在10~108kPa之间的聚氨酯软泡。