Effect of selected boroorganic compounds on thermal and heat properties of rigid polyurethane–polyisocyanurate foams

The effects of three selected borates {tri(hydroxypropyl), tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)‐1‐methylethyl], tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)propyl]} on the heat and thermal properties of rigid polyurethane–polyisocyanurate foams was studied. Increasing the amount of tri(hydroxypropyl) borate and tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)propyl] borate in the foam composition from 0.1 to 0.4 chemical equivalents caused an increase in the softening point, the temperature of the first decrement of foam mass, the extrapolated temperature of the main decrement of the foam mass, and the temperature of the highest rate of the mass decrement. When tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)‐1‐methylethyl] borate was added to the foam compositions, the softening point decreased but the temperatures characterizing their thermal resistance were higher in comparison with the standard foam. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 768–771, 2006     

Effect of selected boroorganic compounds on thermal and heat properties of rigid polyurethane–polyisocyanurate foams

The effect of selected borates [i.e., tri(hydroxypropyl) borate (BTHP), tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)propyl] borate (BTClHPP), and tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)‐1‐methylethyl] borate (BTClHPME)] on the heat and thermal properties of the rigid polyurethane–polyisocyanurate foams was investigated. Increasing amounts of BTHP and BTClHPP in the foam composition, from 0.1 to 0.4 of chemical equivalent, caused increases in the softening point, the temperature of the first decrement of foam mass, the extrapolated temperature of the main decrement of the foam mass, and temperature of the highest rate of the mass decrement. In the case when BTClHPME was added to the foam compositions, the softening point decreased but temperatures characterizing their thermal resistance were higher compared to that of standard foam. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 400–403, 2005     

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     

New polyol for production of rigid polyurethane‐polyisocyanurate foams,Part 2: Preparation of rigid polyurethane‐polyisocyanurate foams with the new polyol

The method of preparation, determination of foaming parameters, and methods for the determination of physicochemical properties of polyurethane‐polyisocyanurate (PUR‐PIR) foams prepared with the use of N,N′‐di(methyleneoxy‐2‐hydroxyethyl)urea and boric acid derivatives are presented in this paper. It was found that application of the borate as a polyol component and simultaneously as a flame retardant in the recipe for production of PUR‐PIR foams was very favorable. The foams prepared were characterized by reduced brittleness, higher compressive strength and content of closed cells, as well as considerably lower flammability in comparison with standard foam. The results show that the new polyol prepared on the basis of N,N′‐di(methyleneoxy‐2‐hydroxyethyl)urea and boric acid can be applied for production of rigid PUR‐PIR foams, and it improves their physicochemical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of liquid‐type silane additives and organoclay on the morphology and thermal conductivity of rigid polyisocyanurate‐polyurethane foams

This article investigates the effects of liquid‐type silane additives and organoclay as a solid‐type additive on the morphological, mechanical and thermal insulating properties of polyisocyanurate‐polyurethane (PIR‐PUR) foams. The organoclay likely acted as nucleating agents during the formation of PIR‐PUR foams. When the liquid silane additives and organoclay were added, the cell size and thermal conductivity of the PIR‐PUR foams appeared to be decreased. However, organoclay did not contribute to reduce the cell size distribution of the foam. PIR‐PUR foams synthesized with tetramethylsilane as a liquid‐type additive showed a smaller average cell size and lower thermal conductivity than that of PIR‐PUR foams synthesized with the other silane additives or with organoclay as a solid‐type additive. For the PIR‐PUR foam with organoclay/TEMS (1.5/1.5 php) mixture, cell size and thermal conductivity of the foam showed similar to the foam with TEMS. These results suggest that smaller cell size appears to be one of the major factors in the improvement of thermal insulation properties of the PIR‐PUR foams. Silane additives did not seem to have a strong effect on the flammability of the PIR‐PUR foams. However, heat resistance was more dominant for the foam with the organoclay at the higher temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Properties of rigid polyurethane‐polyisocyanurate foams modified with the selected fillers

Rigid polyurethane‐polyisocyanurate foams (PUR‐PIR) containing from 2.5% to 20% w/w of fillers (talc, aluminum hydroxide, chalk, starch and borax) were the subject of our studies; a reference sample was PUR‐PIR foam with no filler added. Apparent density, compressive strength, brittleness, content of closed cells, retention (flammability) and softening point of foams were determined and the products were analyzed by thermogravimetric method. These parameters were the basis to determine effect of type and participation of the fillers studied on physicochemical, heat, and thermal properties of foams. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Enhanced fire behavior of rigid polyurethane foam by intumescent flame retardants

Using expandable graphite (EG) and ammonium polyphosphate (APP) as flame retardants, we prepared two series of polyisocyanurate–polyurethane (PIR–PUR) foams (i.e., EG foams filled with different amounts of EG alone and APEG foams containing different amounts of expanded EG and APP) and evaluated the effect of the additives on the physical–mechanical property, fire behavior and thermal stability of the foams based on compressive strength test, limiting oxygen index (LOI), cone calorimeter test, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The addition of EG alone or both EG and APP into the foam greatly influences the physical–mechanical property. The compressive strength of APEG foams is closely related to the apparent density. The LOI value showed good improvement in both EG and APEG foams. The addition of APP in APEG foams gave better fire behavior than the EG foams with an obvious decrease in PHRR and increase in residue. In addition, the TGA curves illustrated that APP might be an effective charring agent to promote char formation. The SEM results showed that the incorporation of APP and EG allowed the formation of a cohesive and dense char layer, which inhibited the transfer of heat and combustible gas and increased the thermal stability of PIR‐PUR. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Expandable graphite in polyurethane foams: The effect of expansion volume and intercalants on flame retardancy

Several expandable graphites (EGs), differing in expansion volume but with the same mean size, are compared as flame retardants in polyurethane (PUR) foams. Not only common sulfur‐intercalated graphites are investigated but also a new one intercalated with phosphorus. The main aim of this article is to understand which properties of EG are important for its flame retardancy effectiveness in PUR foams. Thermal stability, flammability, and fire behavior are analyzed through limiting oxygen index and cone calorimeter tests. Detailed characterization of the phosphorus‐intercalated graphite is also provided as well as physical–mechanical characterization. The results show that the well‐known sulfur‐intercalated graphites and the one with phosphorus both enhance the residue yield, induce a protective layer, and thus efficiently flame‐retard PUR foams. While the expansion volume of the EGs had a surprisingly limited influence on the performance of the foams, at least in the range tested, the most important feature controlling the effectiveness of EG in terms of flame retardant PUR foams was the type of intercalant. The presence of EG affected the physical–mechanical properties of the foams; however, no significant effect of the expansion volume or intercalant type has been revealed on the physical–mechanical properties of the foams. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45173.     

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     

Thermal degradation studies on rigid polyurethane foams blown with pentane

The effect of sodium dihydrogenphosphate, trisodium pyrophosphate, and sodium aluminocarbonate on the thermal decomposition of rigid polyurethane (PUR) foams, based on diphenylmethane‐4,4‐diisocyanate, diphenyl‐2,2‐propane‐4,4‐dioxyoligo(ethylene oxide), and oxyalkylenated toluene‐2,6‐diamine, blown with pentane, was studied. Thermogravimetric (TG) data have shown that there is a stabilization effect of additives in the initial stage of degradation, both in nitrogen and air atmosphere, and the decomposition proceeded in two steps up to 600°C. Results of the kinetic analysis by the isoconversional methods of Ozawa–Flynn–Wall and Friedman yielded values of (apparent) activation energy (E_a) and preexponential factor (A). For phosphate‐stabilized PUR samples, E_a remained stable over a broad area of the degree of conversion, while for carbonate‐containing sample two regions of E_a were observed. Further advanced kinetic analysis by a nonlinear regression method revealed the form of kinetic function that was the best approximation for experimental data—for a two‐stage consecutive reaction the first step was the Avrami–Erofeev nucleation‐dependent model, and the second step was a chemical reaction (1st or nth order) model. The integrated thermogravimetric (TG)/Fourier transform infrared (FTIR) technique probed the thermal degradation of modified PURs by analyzing the evolved gases. The solid residue remaining at different temperatures was identified by diffuse reflection FTIR (Kubelka–Munk format). The complex thermal behavior was discussed on the basis of the obtained results—it can be shown that the global stabilization effect is a multistage process whose initial conditions are of critical importance in governing the nature of the entire process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2319–2330, 2003     

Modification of PUR-PIR foams by boroorganic compound prepared on the basis of di(hydroxymethyl)urea

The method for preparation of boroorganic compound with application of N,N′-di(methyleneoxy-3-hydroxypropyl)urea and boric acid has been described. Then, the borate prepared was characterized mainly in the terms of its usability as a polyol component and fire retardant for production of the rigid polyurethane-polyisocyanurate foams. Method of preparation, the determination of foaming parameters, physicomechanical and fire properties of PUR-PIR foams as well as the results of tests have been presented. The recipe for foam preparation was modified by application of physical and chemical method of foaming. On the basis of the results, it was found that application of the new compound in recipe for production of foams is very favourable. The rigid foams obtained are characterized by lower brittleness, higher compressive strength, lower thermal conductivity and considerably lower flammability in comparison with a standard foam.     

Foamed polyurethane plastics of reduced flammability

In this study, modified foamed polyurethane materials were obtained with the use of new polyols. The polyols were synthesized by the reaction of N,N′‐bis(2‐hydroxyethyl)oxamide esterified with boric acid and various excesses of ethylene carbonate. Thus, poly(ethylene glycol)s with incorporated oxamide and borate groups containing different amounts of boron and nitrogen were obtained. On the basis of these new polyols, rigid polyurethane foams were produced. They contained 0.8–1.2 wt % boron and 7.9–8.5 wt % nitrogen. The resulting foams showed reduced flammability, as determined on the basis of the measurements of the oxygen index and horizontal and vertical flammability tests. The foams also exhibited improved thermal stabilities and mechanical strengths and good dimensional stabilities. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45748.     

Properties of rigid polyurethane foams prepared from recycled aircraft deicing agent with hexamethylene diisocyanate

Polyurethane (PUR) rigid foams were prepared from recycled aircraft deicing agent (aircraft deicing fluid) with reaction of hexamethylene diisocyanate at temperature of 55°C. The effect of [NCO]/[OH] ratio on properties of microscopic structure, cell size distribution, compressive strength, apparent density, as well as thermal conductivity (k) was studied. Higher [NCO]/[OH] ratio helped achieve better micromorphology, higher apparent density, and compressive strength of the PUR foams. With the [NCO]/[OH] ratio of 0.75 and 0.8, some shrinking happened during foam rising, causing a decrease in total volume of the PUR foam, and leading to higher apparent density as well as sharply increased compressive strength. All PUR foams displayed good thermal insulation properties in this study. With [NCO]/[OH] ratio increased from 0.7 to 0.8, the k value increased significantly from 34.3 to 42.2 mW m^?1 K^?1. The k value here was chiefly governed by the apparent density of the foams, which was in turn a function of the ratio of [NCO]/[OH]. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013     

Thermal degradation kinetics of rigid polyurethane foams blown with water

The thermal decomposition behavior of rigid polyurethane foams blown with water was studied by dynamic thermogravimetric analysis (TGA) in both nitrogen and air atmosphere at several heating rates ranging from room temperature to 800°C. The kinetic parameters, such as activation energy (E), degradation order (n), and pre‐exponential factor (A) were calculated by three single heating rate techniques of Friedman, Chang, and Coats–Redfern, respectively. Compared with the decomposition process in nitrogen, the decomposition of foams in air exhibits two distinct weight loss stages. The decomposition in nitrogen has the same mechanism as the first stage weight loss in air, but the second decomposition stage in air appears to be dominated by the thermo‐oxidative degradation. The heating rates have insignificant effect on the kinetic parameters except that the kinetic parameters at 5°C/min have higher values in nitrogen and lower values in air, indicating different degradation kinetics in nitrogen and air. The kinetic parameters of foam samples blown with different water level in formulation decline firstly and then increase when water level increases from 3.0 to 7.0 pph. According to the prediction for lifetime and half‐life time of foams, water‐blown rigid foams have excellent thermostability, when used as insulation materials below 100°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4149–4156, 2006     

混杂增强聚氨酯复合硬质泡沫塑料的研制

系统介绍混杂增强聚氨酯复合硬质泡沫塑料的制备情况，详细分析聚氨酯硬质泡沫塑料制备过程中的工艺问题，表征与分析其结构与性能，着重分析偶联剂对填充物增强性能的影响以及填充物含量对聚氨酯硬质泡沫塑料吸水性能的影响，介绍聚氨酯硬质泡沫塑料的应用，最后指出其发展前景。     

Development of a rigid polyurethane foam from palm oil

The reactions between polymeric diphenyl methane diisocyanate (polymeric MDI) and conventional polyols to produce foamed polyurethane products are well documented and published. Current polyurethane foams are predominantly produced from these reactions whereby the polyol components are usually obtained from petrochemical processes. This article describes a new development in polyurethane foam technology whereby a renewable source of polyol derived from refined–bleached–deodorized (RBD) palm oil is used to produce polyurethane foams. Using very basic foam formulation, rigid polyurethane foams were produced with carbon dioxide as the blowing agent generated from the reaction between excess polymeric MDI with water. The foams produced from this derivatized RBD palm oil have densities in excess of 200 kg/m³ and with compression strengths greater than 1 MPa. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 509–515, 1998     

Synergistic effects of hydroxides and dimethyl methylphosphonate on rigid halogen‐free and flame‐retarding polyurethane foams

Rigid halogen‐free and flame‐retarding polyurethane foams are prepared with aluminum hydroxide, brucite, and DMMP. The effects of the hydroxides and DMMP on the foaming process and flame retarding properties of the foams are investigated by thermo gravimetric analysis, limiting oxygen index, and X‐ray powder diffraction. The thermal stability of the rigid polyurethane foams is close to that of the hydroxide fillers, with aluminum hydroxide providing better flammability performance than brucite. The hydroxide fillers and DMMP play a synergistic role in the rigid polyurethane foams and the limiting oxygen indices are up to 28.4% and 32.4%, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Liquid‐type nucleating agent for improving thermal insulating properties of rigid polyurethane foams by HFC‐365mfc as a blowing agent

The effects of liquid‐type additives on the morphology, thermal conductivity, and mechanical strength of polyurethane (PUR) foams were investigated. The PUR foams synthesized with perfluoroalkane showed a smaller average cell diameter and a lower thermal conductivity than PUR foams prepared with propylenecarbonate or acetone. The average cell diameter of the PUR foams decreased from 228 to 155 μm and the thermal conductivity decreased from 0.0227 to 0.0196 kcal/mh °C when the perfluoroalkane content was 0.0 to 2.0 php (parts per hundred polyol by weight). The perfluoroalkane likely acted as a nucleating agent during the formation of the PUR foams. The addition of perfluoroalkane induced the smaller cells size of the PUR foams probably due to lower surface tension of the polyol and perfluoroalkane mixture, resulting in high nucleation rate. The smaller cell size appears to be the main reason for the improvement in the thermal insulating and the mechanical properties of these PUR foams. The compressive strength of the PUR foams prepared with perfluoroalkane was higher than the PUR foams prepared with the propylenecarbonate and acetone. Based on the morphology, thermal conductivity, and compressive strength, it is suggested that the perfluoroalkane is an efficient liquid‐type additive for the improving the thermal insulation of PUR foams. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43557.     

Highly flame‐retardant polyurethane foam based on reactive phosphorus polyol and limonene‐based polyol

Polyurethane foams are in general flammable and their flammability can be controlled by adding flame‐retardant (FR) materials. Reactive FR have the advantage of making strong bond within the polyurethane chains to provide excellent FR over time without compromising physico‐mechanical properties. Here, phenyl phosphonic acid and propylene oxide‐based reactive FR polyol was synthesized and used along with limonene based polyol for preparation of FR polyurethanes. All the obtained foams showed higher closed cell content (above 96%). By the addition of FR–polyol, the compressive strength of the foams showed 160% increment which could be due to reactive nature of FR–polyol. Moreover, 1.5 wt % of phosphorus (P) content reduced the self‐extinguishing time of the foam from 81 (28% weight loss) to 11.2 s (weight loss of 9.8%). Cone test showed 68.6% reduction in peak heat release rate along with 23.4% reduction in thermal heat release. The change in char structure of carbon after burning was analyzed using Raman spectra which, suggests increment in the graphitic phase of the carbon over increased concentration of phosphorus. It can be concluded from this study that phosphorous based polyol could be blended with bio‐based polyols to prepare highly FR and superior physico‐mechanical rigid polyurethane foams. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46224.     

Preparation and chemical reactions of rigid cross‐linked poly(vinyl chloride) foams modified by epoxy compounds

A novel method to prepare semi‐interpenetrating polymer network rigid cross‐linked poly(vinyl chloride) (c‐PVC) foams with improved shear toughness in the absence of anhydride components is reported. The cross‐linked network structure in the c‐PVC foams was composed of polyurea network modified by epoxy structure. The cellular morphology was characterized by scanning electron microscopy. Tensile, compressive, and shear properties of the foams were studied. The obtained c‐PVC foams showed high shear properties compared with the comparative samples with the same density and cellular morphology. Possible reactions during the preparation of c‐PVC foams were studied by means of Fourier transform infrared spectrometry and nuclear magnetic resonance measurements through the model experiments. The results showed that allophanate structure resulting from the reaction between isocyanate compounds and epoxy compounds formed in the molding step, which was included into the final cross‐linked network in the cross‐linking step. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40567.