Effect of polyethylene glycol on the mechanical property, microstructure, thermal stability, and flame resistance of phenol–urea–formaldehyde foams

Hu, Xiangming; Wang, D. M.; Cheng, Weimin; Zhou, Guangzhu

doi:10.1007/s10853-013-7838-z

Cited by 49 publications

(36 citation statements)

References 19 publications

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“…As shown in Fig. , the phenolic foam oxygen index was directly proportional to the density of the foam, which is consistent with the results obtained in previous studies .…”

Section: Resultssupporting

confidence: 92%

Effect of formaldehyde/phenol ratio (F/P) on the properties of phenolic resins and foams synthesized at room temperature

Zhao

Cheng

2014

Polymer Composites

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Six types of phenolic foaming resins were synthesized at room temperature with different formaldehyde/phenol (F/P) ratios in this study. The effects of F/P ratios on physicochemical characteristics and foaming properties of the resulting resins were analyzed based on viscosity, solids content, hydroxymethyl index, residual monomer content, molecular structure of the foaming resin, flame retardancy, and foam compression strength measurements. The results of the present study indicated that viscosity and solids content of the foaming resins increased with an increase in F/P; the hydroxymethyl index of the resin first increased and then decreased with an increase in F/P, reaching its maximum at F/P = 1.6; the trimer, tetramer, and pentamer contents of the resins increased with an increase in F/P. Nuclear magnetic resonance (13C NMR) spectral analysis indicated that the presence of para/para‐methylene, para‐hydroxymethyl, and ortho‐hydroxymethyl groups in the resin gradually increased with an increase in F/P; the proportions of ortho/ortho‐ and ortho/para‐methylene bonds of the resin increased as F/P was increased. The increase in F/P was demonstrated to be conducive to improving the compression strength, thermal stability, and flame retardancy of the phenolic foam and reducing its peak heat release rate and total smoke release. The morphology of phenolic foams show that the closed cell content in the PF foam increases with the F/P ratio until it reaches a ratio of 1.6. Furthermore, the cell size becomes more uniform. POLYM. COMPOS., 36:1531–1540, 2015. © 2014 Society of Plastics Engineers

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“…As shown in Fig. , the phenolic foam oxygen index was directly proportional to the density of the foam, which is consistent with the results obtained in previous studies .…”

Section: Resultssupporting

confidence: 92%

Effect of formaldehyde/phenol ratio (F/P) on the properties of phenolic resins and foams synthesized at room temperature

Zhao

Cheng

2014

Polymer Composites

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“…It is not hard to comprehend that within a certain length the increase of the length of flexible chain causes lower cross-link density and thus contributes to higher flexural strength as observed in previous work. 12,16 As a result, PEG-BAE is more effective at improving mechanical strength than PEG itself. Figure 12 presents the flexural and compression properties of the PF foams toughened by PEG200-BAE, PEG400-BAE, and PEG600-BAE.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Synthesis of Boron-Containing Toughening Agents and Their Application in Phenolic Foams

Lin

Wang

2015

Ind. Eng. Chem. Res.

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Polyethylene glycol borate (PEG-BAE) toughening agents were prepared from the esterification reaction between boric acid and PEG and characterized by FTIR and NMR. The effect of reaction conditions such as reaction temperatures, reaction times, and entrainer amounts on the esterification reaction rate was studied. Incorporation of PEG-BAE into phenolic (PF) foams leads to an improvement in the flexural and compression strengths, and a reduced pulverization ratio compared with pure and PEG-toughened foams. The LOI results illustrate the flame-retarding effect of PEG-BAE is better than that of pure PEG, with LOI in the range 35.5−39.0%, and all PF foams pass UL 94 V-0 rating. Cone calorimeter results indicate that the incorporation of PEG400 increases the peak heat-release rate (PHRR) of PF foam by 38%, whereas PEG400-BAE results in a slightly decreased PHRR. Moreover, thermal decomposition of pure and toughened PF foams was investigated.

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“…The TGA and DTG curves of the foams thermally degraded in air are shown in Figure 5, and their weight losses can roughly be divided into three stages: The first stage at temperatures before 360 • C is mainly due to the water removal and the volatilization and oxidation of light compounds in the furanic-glyoxal foams [34]. The main weight loss occurs in the third stage at temperatures in the 400 to 650 • C range, and 50% of weight loss occurs after 510 • C. This indicates that these foams have good heat resistance.…”

Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 99%

Characterization and Preparation of Furanic-Glyoxal Foams

Pizzi

Lei

et al. 2020

Polymers

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Synthetic foams have become an essential industrial product for a great variety of applications. Furfuryl alcohol, as a biomass chemical, was reacted with glyoxal at room temperature to prepare furanic-glyoxal rigid foams, and p-toluenesulfonic acid was used as a catalyst to initiate the reaction. Foams with different molar ratios (furfuryl alcohol/glyoxal) were prepared in this work, and uniform cells foams have been obtained. Their compression resistance, 24-h water absorption, density, and other basic properties were tested. Scanning electron microscopy (SEM) was used to observe the cellular morphology of the foams prepared, thermogravimetric analysis (TGA) helped to understand their thermal and combustion properties, and FTIR and Matrix Assisted Laser Desorption Ionisation Time of Flight (MALDI ToF) mass spectroscopy to explain the structure of the resulting foams to clarify the reactions occurring during foaming. The results show that the compression resistance of furanic-glyoxal foams declined as the furfuryl alcohol/glyoxal ratio decreases also. SEM observations revealed that foams with open-cell were obtained when furfuryl alcohol was added in greater amounts, and more closed cell structures were formed as the proportion of glyoxal increased. TGA results showed that the initial ignition temperature of furanic-glyoxal foams is ~200 °C higher than that of wood, and the smaller comprehensive combustion index S (about 0.15 × 10−7 (%2 K−3 min−2)) indicates that the foam burns slowly and has poor flammability, that is, it is not easy to burn.

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Effect of polyethylene glycol on the mechanical property, microstructure, thermal stability, and flame resistance of phenol–urea–formaldehyde foams

Cited by 49 publications

References 19 publications

Effect of formaldehyde/phenol ratio (F/P) on the properties of phenolic resins and foams synthesized at room temperature

Effect of formaldehyde/phenol ratio (F/P) on the properties of phenolic resins and foams synthesized at room temperature

Synthesis of Boron-Containing Toughening Agents and Their Application in Phenolic Foams

Characterization and Preparation of Furanic-Glyoxal Foams

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