Thermal Degradation and Stability of Accelerated-curing Phenol-formaldehyde Resin

Chen, Yuzhu; Fan, Dongbin; Qin, Tefu; Chu, Fuxiang

doi:10.15376/biores.9.3.4063-4075

Cited by 14 publications

(12 citation statements)

References 17 publications

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“…The curing time was measured by adding NH 4 Cl hardener at the 3% level of resins at 100 °C according to the Ref. The measurements were done with three replications for each sample.…”

Section: Methodsmentioning

confidence: 99%

Effect of a novel environmentally friendly additive of polyaspartic acid on the properties of urea formaldehyde resins/montmorillonite

Zhou

Yang

Zheng

et al. 2019

J of Applied Polymer Sci

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Polyaspartic acid (PASP) is a biodegradable green material with carboxyl groups ( COOH) and amido groups ( CO NH ). In the article, a novel urea-formaldehyde (UF) resin modified by PASP and Ca-montmorillonite (Ca-Mt) was prepared by the alkalineacid-alkaline method. The synthesized materials were characterized by X-ray diffraction, Fourier transform-infrared spectroscopy, thermal analysis (TG-DTG), and scanning electron microscopy. The effects of viscosity, curing time, and free formaldehyde were investigated. The results showed that the layered structure of Ca-Mt was exfoliated and dispersed in the bulk of UF. The thermal stability of the modified UF was much better than that of pure UF resin. The percentage of free formaldehyde was declined from 26 to 18%. Meanwhile, the UF composites showed the short curing time and the optimum viscosity. Finally, a synthetic process of UF modified by PASP and Ca-Mt and a possible mechanism for immobilizing the free formaldehyde were suggested.

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“…The curing time was measured by adding NH 4 Cl hardener at the 3% level of resins at 100 °C according to the Ref. The measurements were done with three replications for each sample.…”

Section: Methodsmentioning

confidence: 99%

Effect of a novel environmentally friendly additive of polyaspartic acid on the properties of urea formaldehyde resins/montmorillonite

Zhou

Yang

Zheng

et al. 2019

J of Applied Polymer Sci

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“…Hypothetically the stiffness of hot-pressed composites made from bamboo could be higher than the parent material, but the hot pressing regime used here does not appear to have been able to sufficiently stiffen the bamboo tissue. This is probably because the curing temperature of 150°C is in the upper range recommended for curing PF resin (Chen et al 2014), and the hot pressing duration under 7 min is lower than the optimal set of heat treatment conditions required to increase the strength and stiffness of bamboo tissue simply through heating; which are 180-200°C and over 20 min exposure (Schott 2006).…”

Section: Thickness Swell/water Absorptionmentioning

confidence: 99%

Hybrid oriented strand boards made from Moso bamboo (Phyllostachys pubescens Mazel) and Aspen (Populus tremuloides Michx.): species-separated three-layer boards

2015

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Five sets of three-layer OSB were made from aspen and/or Moso bamboo strands in the following three configurations: Aspen strands in the surface and core layers; Moso strands in the surface and core layers; and Moso strands in the surface and aspen strands in the core. Boards containing Moso strands in the surface layers had two sub groups: (1) all strands contain a node in the middle, and (2) all strands are node free (internode). All 30 boards were comprised of 50 % w/w surface furnish and 50 % core furnish, fabricated to 737 mm 9 737 mm 9 11.1 mm. Standard mechanical (thickness, density, surface and core density) and strength properties [internal bond (IB), flexure, lateral nail withdrawal resistance (LNR)], and water resistance [2 and 24 h thickness swell (TS) and water absorption (WA)] were assessed. Complete replacement of the aspen in the surface layers with internode Moso strands resulted in over 45 % greater MOR. Panels made with Moso surface layers met CSA O437.0 (2011) minimum requirements TS/WA without the need for wax addition, possibly because no densification of the surface material was observed. Due to high variance in LNR, effects of board type and core composition were not statistically significant, but LNR of boards exceeded CSA O437.0 minimum requirements. Moso bamboo surface OSB were low in MOE which is consistent with unadulterated tissue being high in bending strength and fracture toughness but low in specific stiffness. The presence of nodes in the bamboo strands significantly reduced the strength properties of OSB, a problem which could be mitigated by minimising the incidence of nodes in the strands, particularly those used in the surface layers.

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“…Previous works have shown that Na 2 CO 3 could accelerate phenolic resin curing, resulting in a short hot pressing time for the preparation of plywood panels . The distribution of ortho – para / para – para linkages and resin curing kinetics could be affected by the addition of carbonates was also reported .…”

Section: Resultsmentioning

confidence: 91%

Curing properties of high‐Ortho phenol‐formaldehyde resins with co‐catalysis

Zhu

Zhang

et al. 2018

J of Applied Polymer Sci

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In this study, sodium carbonate (Na 2 CO 3 ) was used as a catalyst to prepare high-ortho phenol-formaldehyde (HOPF) resin, and ester and carbonate curing accelerators were used to increase its curing rate. The physicochemical properties of the prepared resins and the mechanism of curing acceleration were investigated. The results showed that, with the addition of Na 2 CO 3 , the ortho/para ratio of methylol groups increased from 7.257 to 27.800. The gel time of the cure-accelerated HOPF resins decreased from 620 to 240 s as compared with PF resin. The bonding strength of plywood bonded with the cure-accelerated HOPF resins were all above 0.70 MPa. The curing acceleration was caused by the carbonate ions rather than the metal ions, and a temporary incorporation mechanism apparently occurred for the ester accelerators. The prepared phenolic resin had fast curing rate, low curing temperature, high thermal stability, and favorable mechanical performance, which has potential for industry applications.

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Thermal Degradation and Stability of Accelerated-curing Phenol-formaldehyde Resin

Cited by 14 publications

References 17 publications

Effect of a novel environmentally friendly additive of polyaspartic acid on the properties of urea formaldehyde resins/montmorillonite

Effect of a novel environmentally friendly additive of polyaspartic acid on the properties of urea formaldehyde resins/montmorillonite

Hybrid oriented strand boards made from Moso bamboo (Phyllostachys pubescens Mazel) and Aspen (Populus tremuloides Michx.): species-separated three-layer boards

Curing properties of high‐Ortho phenol‐formaldehyde resins with co‐catalysis

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