Hierarchical Lamellar Aluminophosphate Materials with Porosity as

Subscriber access provided by Oregon Health & Science University Library

Hierarchical Lamellar Aluminophosphate Materials with Porosity as Eco-friendly Inorganic Adhesive for Wood-based Boards Tingjie Chen, Zhenzeng Wu, Xiaodong Wang, Wei Wang, Daobang Huang, Qihua Wei, Binghui Wu, and Yongqun Xie ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.8b00078 • Publication Date (Web): 22 Mar 2018 Downloaded from http://pubs.acs.org on March 22, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

Hierarchical Lamellar Aluminophosphate Materials with Porosity as Eco-friendly Inorganic Adhesive for Wood-based Boards Tingjie Chen,a , b ‡ Zhenzeng Wu,a, ‡ Xiaodong (Alice) Wang,d Wei Wang,a Daobang Huang,a Qihua Wei,a Binghui Wu,c,* and Yongqun Xie a,* a

: College of Material Engineering, Fujian Agriculture and Forestry University, 15

Shangxiadian Road, Fuzhou, Fujian, 350002, P. R. China.; b

: Collaborative Innovation Center of Chemistry for Energy Materials, Department of

Chemistry, College of Chemistry and Chemical Engineering, 422 South of Siming Road, Xiamen University, Xiamen, Fujian, 361005, P. R. China; c

: Pen-Tung Sah Institute of Micro-nano Science and Technology, Xiamen University, 422

South of Siming Road, Xiamen, Fujian, 361005, P. R. China; d

: Department of Wood and Forest Sciences, Laval University, Quebec, G1V 0A6, Canada

E-mail for authors：：[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected] E-mail for corresponding authors：：[email protected]; [email protected]

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

AUTHOR INFORMATION

Corresponding Author

*Address: College of Material Engineering, Fujian Agriculture and Forestry University, 15 Shangxiadian Road, Fuzhou, Fujian, 350002, P. R. China. Phone: +86 591 83789307. Fax: +86 591 83789135. E-mail: [email protected]. E-mail: [email protected]

Author Contribution

‡Tingjie Chen and Zhenzeng Wu contributed equally to this work


Page 2 of 33

Page 3 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


KEYWORDS: Aluminophosphate, Characterization, Adhesive, Rheological behavior, Wood fiber.

ABSTRACT.

Aluminophosphate inorganic adhesive (APIA), as a binder for wood-based

boards (WBB), is synthesized between Al(OH)3 and H3PO4 in solution with hydrothermal treatment in this study. Aluminophosphate compounds with hierarchical lamellar structure are observed on the fibers’ surface. The rheological behavior analysis reveal that the viscosity of APIA varied with its P/Al molar ratio [n(P)/n(Al)]. P-O-Al bridges are formed during the hydrothermal treatment of the APIA. The covalent bonds of P-O-C, as well as hydrogen bonds, are formed between APIA and wood fibers, which could explain the improvement in mechanical properties of the WBB. In this study, the optimal n(P)/n(Al) in APIA is found to be 2.8, where the bonding strength, together with an acceptable viscosity are found at 1.83 MPa and 31.3 m Pa·s, respectively. Thermogravimetric analysis indicates that the residual weight of plywood is 44.97% greater than pure wood fibers, indicating that the fire resistance of the WBB in the study is improved.



Page 4 of 33

INTRODUCTION

Due to rising environmental and societal concerns, many researchers find inspiration from

nature

to

develop

and

apply

‘green’

ideas

to

reach

the

goal

of

a

low-environmental-impact society. Wood and wood-based products, including particleboard, plywood, and medium density fiberboard, as a renewable, eco-friendly, bio-degradable natural resource are widely used in home and public buildings.1-2 Owing to many advantages such as low cost, high reactivity and excellent interface adhesion performance to wood based materials, formaldehyde adhesives, including phenol formaldehyde resin, urea formaldehyde resin and melamine urea formaldehyde resin, are commonly used in wood-based products.3-5 Nevertheless, these adhesives would release formaldehyde in certain circumstance, which is a dangerous and genotoxic air pollutant. It is classified as a human carcinogen by the U.S. Environmental Protection Agency, which would cause DNA adduct formation.6-8 To overcome this problem, non-formaldehyde adhesives, such as wheat flour,9 lignin,10 starch,11-12 soybean protein,13-15 and polyvinyl acetate,16 have been the subject of numerous investigations for use in the wood-based products. However, the practical application of these adhesives in our daily life is still limited by their poor water-resistance, fungi resistance, and insufficient mechanical properties to wood products.17-18

Phosphate-based binders reacted between phosphate solutions and metal oxides, including the divalent and trivalent metal oxides of magnesia (MgO), alumina (Al2O3), and hematite (Fe2O3), have been investigated for many years.19-21 Aluminophosphate adhesive, as one kind of phosphate-based binders without formaldehyde, could be formed by natural


Page 5 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


aluminum minerals and phosphoric acid (H3PO4) in solution. The continuous chain-like structure or three-dimensional net structure in the aluminophosphate adhesive formed after curing, indicated a high mechanical strength, which would be beneficial for an adhesive. The aluminophosphate adhesive exhibits prominent thermal stability, cost-effectiveness, corrosion-resistance, and long service life.22-25 It can be used in various applications, such as adhesives, as a heterogeneous catalyst for conversion of biomass to hydrocarbons, ceramic coating on metal or cement components, and as a structural adhesive in rockets or other aircrafts having high-temperature oxidative and abrasive environments.26-27 However, aluminophosphate compounds have not been previously utilized as an inorganic adhesive for preparing the wood-based boards (WBB).

The objective of this study is mainly focusing on the formation of aluminophosphate inorganic adhesive (APIA) for manufacturing WBB. APIA, as a non-formaldehyde adhesive, is synthesized from H3PO4 solution and aluminum hydroxide [Al(OH)3]. To discuss the formation mechanism and the structure of aluminophosphate compounds, the morphologies, chemical bonding, and rheological property of APIA are tested and analyzed. Additionally, to clarify the reaction between APIA and wood fibers, the microstructures, chemical structures, mechanical performance, and thermal stability of WBB are also discussed in this study.

EXPERIMENTAL SECTION

Materials

Poplar veneers and fibers (Fujian Furen Wood Industry Co., Ltd, Fuzhou, China) were used as raw material to prepare WBB. Al(OH)3 and H3PO4 (concentration of 85%), which



were used to prepare APIA, were purchased from Tianjin Zhiyuan Chemical Reagents Factory (Tianjin, China). Ferric oxide (Fe2O3) purchased from Jiangsu Henglong Pigment Co., Ltd. (Xuzhou, China), was employed as curing agent.

Methods

Preparation of aluminophosphate inorganic adhesive and wood-based boards

The APIA is formed by a hydrothermal reaction between Al(OH)3 and H3PO4 solution. The dilute H3PO4 solution with a concentration of 55% in volume is added into round-bottom flask (500 mL), where the Al(OH)3 powder is slowly added into the H3PO4 solution, experiencing a vigorous stirring for 20 min at 85 °C, followed by 20 min at 110 °C. The obtained APIA is mixed with the Fe2O3 (1.5% of total adhesive weight) and then used to prepare duplicate samples of plywood, by coating each veneer layer with 100g/m2 of the adhesive. The assembly time, hot-press temperature, pressure, and time in the hot-press are 20 min, 160 °C, 1.0 MPa and 5 min, respectively. The detail preparation process of APIA and WBB is described in Figure 1. The APIA in this study is synthesized with various P/Al molar ratios [n(P)/n(Al) = 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, and 3.1:1], from here on referred to as APIA-2.2, APIA-2.3, APIA-2.4, APIA-2.5, APIA-2.6, APIA-2.7, APIA-2.8, APIA-2.9, APIA-3.0, and APIA-3.1, respectively.


Page 6 of 33

Page 7 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 1. Preparation process of aluminophosphate inorganic adhesive and poplar plywood.

Materials Characterization

The rheological behavior of APIA was tested by a rotational rheometer with a PP35Ti parallel plate (HAAKE MARS III, Thermo Electron, USA). The shearing stress on the APIA was tested at 25 °C with the shear rate ranging from 10γ/s to 1000γ/s. The viscosity was tested at a set velocity gradient of 10γ/s, with the temperature ranged from 25 to 190 °C, and a heating rate of 10 °C/min. The reaction mechanisms among Al(OH)3, H3PO4, and wood fibers were carried out by a Nicolet 380 Fourier transform infrared spectroscopy (FT-IR, Thermo Electron Instruments, USA), X-ray photoelectron spectroscopy (XPS, ESCALAB 250, USA), a Nuclear Magnetic Resonance (NMR, Bruker ADVANCE III 500, Switzerland) spectrometer, and X-ray diffraction (XRD, X’Pert PRO MPD, Philips-FEI, Netherlands). FTIR was employed by the KBr pellet method with a range from 4000 to 400 cm-1. XPS experiments were carried out at ambient temperature in an ultra-high vacuum system with Al Kα radiation, the pass energy of 100 eV, the energy step size of 1.00 eV, and the spot size of



500 µm. The 31P and 27A1 NMR spectra were recorded by 4 mm zirconia oxide rotor with a spinning rate of 10 kHz at room temperature. The typical diffraction pattern and intensity profile of APIA and WBB were recorded by Co Kα radiation with a 5 mm variable divergence slit (2θ) between 5.0° and 60.0°.

The microstructures of specimens were analyzed by scanning electron microscopy with an energy-dispersive spectroscopy at an acceleration voltage of 15 kV (SEM-EDS, Phenom ProX, Netherlands). And their specific surface area and pore size distribution were performed by the N2 adsorption-desorption experiments (JW-BK132F, China). The thermogravimetric analysis (TGA) of APIA and WBB were obtained by a thermogravimetric analyzer (NETZSCH STA 449F3, Germany) with a heating rate of 10 °C min-1 under nitrogen atmosphere, ranging from 20 °C to 600 °C. The bonding strength of plywood with the size of 100 mm × 25 mm (L × W) was tested by a tensile testing machine (MTS, USA) at a constant speed of 10 mm/min according to Chinese National Standards GB/T 9846-2015. The reported results are the average of ten specimens.

RESULTS AND DISCUSSION

Characterization of aluminophosphate inorganic adhesive

As seen in Figure 2a and Figure S1, the FTIR spectra of H3PO4, Al(OH)3, and aluminophosphate shown the -OH bending and stretching vibrations peaks around 3300 cm-1. For the spectrum of Al(OH)3, the indistinctive peaks around 1004, 973, and 610 cm-1 are


Page 8 of 33

Page 9 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


attributed to the υAlO6, δs, and Al-OH vibrations, respectively.30-31 In Figure 2a and Figure S1, the spectrum of H3PO4 at 2394, 1161, 992, 885, and 486 cm-1 are attributed to the P-OH vibrations, P=O stretching vibrations, terminal P-O- stretching vibrations, P-O-P asymmetric stretching vibrations, and P-O- vibrations, respectively.32-33 The infrared spectra of aluminophosphate display almost the same characteristic bands as H3PO4 except for the peak near 1161 cm-1, which is attributed to the stretching mode of P=O double bonds in the phosphate tetrahedral.28-29 It can be confirmed that the P-O-Al bridge bonds are formed by breaking the P=O bonds in the reaction between H3PO4 and Al(OH)3.34

Figure 2. (a) FTIR spectra region from 1500 to 400 cm-1 of H3PO4 and aluminophosphate; (b) Changes in viscosity of APIA with different P/Al molar ratio versus velocity gradient; (c) Changes in shearing stress of APIA with different P/Al molar ratio versus velocity gradient; (d) Changes in viscosity of APIA-2.3 versus temperature.



To further analyze the characteristics and synthesis mechanism of the APIA, the viscosity of APIA with different P/Al molar ratio versus temperature, and the shearing stress of APIA with different P/Al molar ratio versus rate of shear were investigated (Figure 2b, c, and d). The viscosity is the constant of proportionality between the shearing stress and the velocity gradient and can be modeled with the equation τ=µγ, where τ is the shearing stress of APIA (m Pa), µ is the viscosity of APIA (m Pa·s), and γ is the velocity gradient (S-1).35 The constant value of η indicates that APIA behaves as a Newtonian fluid, which controls by an important physical parameter of viscosity (Figure 2b and c). As presented in Figure 2d and Table 1, the viscosity of APIA-2.3 declined slightly when the temperature reaches 100 °C from ambient temperature, then increased sharply at higher temperatures, reaching a maximum viscosity at Tmax=156.4 °C (Tmax means temperature at max viscosity). When temperatures are above Tmax, the viscosity decreased again. This is because that the mobility of the aluminophosphate oligomer, formed between Al(H2O)63+ and H3PO4 and H2PO4− in the low pH solution, improved at higher temperatures.29, 36 With increased temperatures, the viscosity of APIA increases sharply due to a large amount of the aluminophosphates oligomers becoming partially or fully condensed to form the Aloct-O-Ppar, Altet-O-Ppar, or Altet-O-Pful orbicular structures.28 With further increase in temperature (above Tmax), the orbicular structures of aluminophosphates are broken to form catenulate structures, leading to decreased viscosity.36-39

Table 1. The viscosity at room temperature (ηRT) and the maximum viscosity at Tmax (ηmax) of APIA with different P/Al molar ratio.


Page 10 of 33

Page 11 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


n(P):n(Al) 2.2 ηRT (m Pa·S) ηmax (m Pa·S) Tmax (°C)

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

3.1

333.9

179.4

136.9

114.3

81.5

31.3

62.6

34.2

30.8

67535 14940 4143

3681

2224

2439

1445

1042

1085

1099

151.5

159.6

160.4

162.3

163.5

167.9

169.5

182.8

530.0

156.4

157.8

Additionally, the viscosity of APIA with different P/Al molar ratio illustrates different results set against temperature (Figures S2 and Table 1). The ηRT and ηmax decrease with increasing P/Al molar ratio, while Tmax increases with increasing P/Al molar ratios. This is due to an excess amount of Al(OH)3 in the reaction solution at P/Al molar ratios lower than 2.3. The more Al(OH)3 that remained in the solution, the lower the fraction of Al(H2PO4)3 in the adhesive, which increased the viscosity of APIA. On the contrary, if the amount of H3PO4 in the reaction solution becomes excessive, the viscosity decreases.23, 40 As we know, the viscosity of adhesives is very important for the applications in wood-based boards. For fiberboards and oriented strand lumber, adhesives with low viscosity would be well distributed among the wood pieces to bind the pieces together. Differently, to make adhesive partially sinks into the wood and also holds out on the surface to provide contact between the two veneers, a much higher viscosity of adhesive is needed for plywood. So, the main concerns of developing inorganic adhesives for wood-based boards are their viscosities and curing temperatures, which is in turn affected by the P/Al molar ratio of APIA. To promote cross-linking and complete solidification of APIA in wood-based composites, a low viscosity (below 500 m Pa·s) and a low curing temperature of the APIA are desired.41-42 Therefore, the optimal P/Al molar ratio in APIA would be within the range from 2.3:1 to 3.0:1. Additionally,



the APIA is no sigh of cure after more than 6 months storage, indicating a long self-life for adhesive.

Micromorphology and interfacial adhesion of wood-based boards

Figure 3. (a) and (b) Microscopic images of fiber without and with aluminophosphate inorganic adhesive; (c) the magnifying images of hierarchical aluminophosphate compounds from the square in b; (d) Hierarchical lamellar structural model of aluminophosphate compounds (Modified from Xu et al.29); (e) A cross-sections image of fiber with aluminophosphate inorganic adhesive and (f) its corresponding element mappings (containing carbon, oxygen, phosphorus and aluminum elements).

As shown in Figure 3a, the surface of fibers (get from veneer) without APIA exhibits a typical smooth surface with the visible grains and pits. The fibers treated by APIA present a rough and compact surface, where the concave strips and pits are covered by adhesive (Figure 3b). At higher magnification, the hierarchical lamellar structures with some


Page 12 of 33

Page 13 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


micro-pore formed by the aluminum and phosphorus species can be observed (Figure 3c). It can be assumed the formation of Al-O-P units between Al tetrahedron and the fully condensed P sites. The hierarchical lamellar structures are considered to be stacked up by these Al-O-P units.28-29 The triaxial structural model of aluminophosphate hierarchical lamellar structures, which was modified from Xu,29 is presented in Figure 3d. A typical BET curve of the aluminophosphate material implies the existing of a micropore structure with the pore diameter around 2-5 nm (Figure S3). These micropores might be produced during the hot-pressing process which could provide pathways for the released water vapor. Further confirmed the deposition of aluminophosphate compounds on fibers’ surface, the cross-section images and corresponding elements mapping of the fiber from wood-based composites are presented in Figure 3e and f. It shows that a micron-dimension inorganic film including phosphorus and aluminum elements is deposited around the fibers. This sign of good interfacial adhesion is probably due to the large amounts of concave strips and the polar groups of APIA, especially the hydroxyl groups. A good interfacial adhesion may account for the improved mechanical performance of wood-based boards.41

Figure 4. (a) Typical XPS of C1s core levels in pure fibers and WBB; (b) and (c) Typical XPS of P2p and Al2p in aluminophosphate inorganic adhesive and WBB.



To clarify the chemical bonding between APIA and wood fibers, the surface chemistry of APIA and WBB are investigated by XPS. As presented in Figure 4a, the typical C1s peaks at 284.6, 286.4, and 286.6 eV correspond to C-C/C-H, C-O, and C=O groups, respectively.43 Compared to pure fibers, the intensity of peak at 286.4 eV decreases when the APIA is the used for WBB. This is because the formation of hydrogen bonds and covalent bonds between fibers and APIA tie up substantial amounts of hydroxyl groups. The P2p and Al2p peaks of APIA and WBB are revealed in Figure 4b and c, respectively. The characteristic Al2p and P2p peaks of APIA are present at 74.87 and 134.14 eV, which is lower than the WBB with the binding energy of 75.01 and 134.43 eV, a difference of 0.14 and 0.29, respectively. Owning to the electronegativity of O (3.44), C (2.55), and P (2.19), the electronegativity variance of O-C and O-P are 0.89 and 1.25, respectively, indicating that the O-C absorbs the electrons more easily than O-P. This means that the P element’s electron cloud in plywood is lower than APIA, leading to an apparent shift of P2p peak from 134.14 eV to 134.43 eV. The results of C1s peaks and P2p peak indicate that the formation of P-O-C covalent bond between APIA and wood fibers.43-46 Similarly, O-Al with the electronegativity variance of 1.83 more easily absorbs the electrons than O-C. If Al-O-C covalent bonds were formed, the Al2p binding energy in the WBB should be lower. But the Al2p binding energy of plywood is higher than APIA, indicating there is only the formation of hydrogen bonds between APIA and fibers.


Page 14 of 33

Page 15 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 5.

27

Al and

31

P MAS NMR spectra of aluminophosphate inorganic adhesive and

WBB.

To further analyze the framework phosphorus and aluminum oxide, the

27

Al MAS

NMR and 31P MAS NMR spectrums of APIA and WBB are presented in Figures 5. The 27A1 NMR spectrum of APIA exhibits two weak peaks at around 75.5 and 41.9 ppm, respectively, which are ascribed to the tetrahedral Al in aluminophosphate. A sharp peak at -14.5 ppm is associated with the octahedral aluminum, indicating that nearly all the A1 atoms in APIA are presented in octahedral environment.47-48 For the

27

A1 spectrum of WBB, similar peaks

around 77.9, 42.1, and -10.9 ppm are observed, with the exception that the increasing of tetrahedral Al intensity. This indicates that most of Al is in tetrahedral coordination.49-50 The 31

P MAS NMR spectrum of APIA at around -15.2 and -23.7 ppm, which could be attributed

to the partially and fully condensed phosphate species in aluminophosphate framework.49, 51-53

Differently, the

31

P spectrum of WBB displays only a peak at -13.0 ppm mainly

ascribing to the fully condensed P to four Al atoms in its coordination sphere.51-52 In this study, the pH value of APIA solution is around 3.8. On the basis of Xiang’s28 work, the aluminum hydroxide mainly consists of Al(H2O)63+ cation and a smaller fraction of Al(OH)4− anion. In low pH solution, there are mainly H3PO4 and H2PO4− anions in the H3PO4 solution.



Therefore, two possible reaction mechanisms are possible as presented in Scheme 1. The Al(H2O)63+ and Al(OH)4- are attacked by an aprotic oxygen from H3PO4 and H2PO4−, are denoted as Pathways 1 and 2, respectively.

Scheme 1. Pathways to polyreaction among Al(OH)4-, Al(H2O)63+, H3PO4, and H2PO4− in solution with a pH value around 3.8, and the reactions between APIA and wood fibers.

Thermogravimetric analysis of aluminophosphate inorganic adhesive and wood-based boards

The thermogravimetric (TG) analysis which could be exactly recorded the mass loss of the sample versus temperature is well-established for on-line pyrolysis of wood fibers.55 So, the TG and differential thermogravimetric (DTG) curves of APIA, pure fibers, and WBB subjected to heat in the range 25-600 °C are shown in Figure 6 and S4. There is a total weight


Page 16 of 33

Page 17 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


loss of 32.99% for APIA. The first stage with the weight loss of 3.44% is caused by evaporation of moisture.55 Then, a total weight loss of 27.22% occurred at 130.3 °C and 153.1 °C, causing by the loss of interlayer water from the crystalline hydrate [AlH3(PO4)2·3H2O and AlH3(PO4)2·H2O].23 The last stage of weight loss (2.33%) is a result of the thermal dehydroxylation process.

Figure 6. TG curves of aluminophosphate inorganic adhesive, pure fibers, and WBB.

For fibers, three distinct weight loss stages are accounted for 7.41%, 58.52% and 24.17%, respectively, which is attributed to the loss of free- and chemically bonded moisture, and the thermal dehydroxylation process.54-56 Differently, the WBB has a lower total weight loss (45.13%) than the pure fibers. The weight loss for WBB also exhibits three distinct stages at 9.58%, 23.73%, and 11.82%, respectively. There are two weight loss peaks at 121.8 and 227.9 °C, indicating that the AlH3(PO4)2·3H2O and Al(H2PO4)3 are transferred into AlH3(PO4)2·H2O and AlH2P3O10.23 As shown in Figure S4, the maximum weight loss of pure fibers and WBB appear at 335.1 °C and 227.9 °C, respectively, indicating that APIA as a wood binder could affect the themalstability of WBB. However, the total weight loss of the WBB is 44.97% lower than the pure fibers.



Figure 7. XRD patterns of fibers, WBB, and their residues obtained from fibers and WBB carbonized at 1000 °C in nitrogen atmosphere.

To further analyze the formation of aluminophosphate crystals, the X-ray diffraction patterns of fibers, burning fibers, WBB, and burning WBB are showed in Figure 7. The diffraction peaks of fibers displayed the typical 101 (2θ=14.01°) and 002 (2θ=22.38°) planes of cellulose I.57 After fibers burned off at 1000 °C in nitrogen atmosphere, the disappeared 101 plane and the decreased crystallinity values indicate the formation of amorphous carbon. For composite with APIA, the diffraction peaks become much weaker, which is ascribed to the addition of amorphous aluminophosphate compounds. Interestingly, the additionally peaks around 2θ=21.68° and 35.96° are observed in WBB burned off at 1000 °C, which are similar to the AlPO-17 crystals.58-59 Therefore, it can be concluded that the residues are not only consisting of the amorphous carbon and aluminophosphate compounds, but they also contain the AlPO-17 crystals, which would greatly improve the ability against fire of WBB.60

Mechanical property of wood-based boards


Page 18 of 33

Page 19 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


One of the main concern in developing APIA for WBB is the impact of its viscosity on bonding strength of the boards, especially when spray application methods are employed (viscosity of the adhesive should be below 500 m Pa·s).42 So, the bonding strength of plywood is presented in Figure 8a. The results demonstrate a two-peak profile when the n(P)/n(Al) ratio of the AIPA ranges from 2.2 to 3.1. As seen in Figure 8a, the plywood with 2.3 in n(P)/n(Al) (first peak) shows the highest bonding strength of 2.18 MPa, which is comparable to many WBB reported until now (Figure S5). The occurrence of first peak is mainly due to the variation in viscosity of the APIA. As the n(P)/n(Al) ratio of the AIPA decreased (< 2.3), the APIA becomes increasingly viscoelastic (< 500 m Pa·s) and opaque, which has a negative effect with spray application. When the n(P)/n(Al) is lower than 2.3, there is extra Al(OH)3 deposited in the plywood, besides the phase of Al(H2PO4)3. The more Al(OH)3 that remains, the less the percentage of Al(H2PO4)3 in the APIA, which results in a decrease of the bonding strength between the wood fibers and APIA,23 and a corresponding decrease in the bonding strength of the plywood. On the contrary, when the n(P)/n(Al) ratio is greater than 2.3, the bonding strength of plywood decreases as a result of a decrease in the viscosities of APIA, which behaves as a Newtonian fluid. With increased n(P)/n(Al) ratios, the complete reaction between H3PO4 and Al(OH)3 monomer is occurring up to the second peak at n(P)/n(Al)=2.8. This is because the APIA with optimal n(P)/n(Al) ratios have cured completely in the hot-pressing process. Subsequently, with a further increase in n(P)/n(Al), the amount of H3PO4 in the reaction solution becomes excessive. The extra phosphoric acid remaining in the APIA may react with other additives or deteriorates the wood fibers, which decreases the bonding strength of the plywood by reducing the adhesive strength.23, 40 To



Page 20 of 33

guarantee the applying of APIA easily in both plywood and MDF, the optimal n(P)/n(Al) of APIA should be around 2.8. Here, the bonding strength of the plywood is 1.83 MPa, which is higher

than

the

general-used

plywood

standards formulated

by

Standardization

Administration of China (Beijing, China).62

Figure 8. (a) Bonding strength of plywood with different P/Al molar ratio. (b) Microscopic images of the tensile-fractured surfaces of WBB. (c) SEM image of hierarchical lamellar aluminophosphate material with microporous prepared from WBB after calcination at 1000 °C in nitrogen atmosphere. (d) Surface of hierarchical lamellar aluminophosphate material with microporous at higher magnification.

Additionally, the fractured surfaces of the WBB show that the fibers are mostly fractured at the indistinct fiber/adhesive interfaces, indicating good interfacial adhesion between fibers and APIA (Figure 8b).41 This is probably due to the existing of hydrogen bonding and even covalent bonding in WBB. As seen in Figure 8c and d, the WBB remains its original framework when organics are removed by calcination. This might be caused by the thin aluminophosphate inorganic film around the fibers’ surfaces.62-63 Due to the unique


Page 21 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


structure-mechanical properties, the integrated hierarchical lamellar aluminophosphate material with porosity as an inorganic binder is beneficial to improve the mechanical properties of WBB.

CONCLUSION

In summary, we have demonstrated that aluminophosphate inorganic adhesive (APIA) synthesized between Al(OH)3 and H3PO4 solution can be used in wood-based boards. After hydrothermal treatment, the bridge bonds of P-O-Al are formed in the APIA. With increasing temperatures, aluminophosphates changed from the oligomer to the Aloct-O-Ppar, Altet-O-Ppar, or Altet-O-Pful orbicular structures, and then to the catenulate structures at temperatures above the temperature of maximum viscosity. APIA deposited on the fibers’ surface and presented a hierarchical lamellar structure. Hydrogen bonds and P-O-C covalent bonds were formed in WBB, which improved the mechanical properties of WBB. In this study, the fire resistance of the plywood was improved by using APIA. This study also shows that, based on considerations of mechanical properties and process ability, the optimal n(P)/n(Al) in APIA should be around 2.8.

ASSOCIATED CONTENT

Supporting Information FTIR spectra of H3PO4, Al(OH)3, and aluminophosphate; Viscosity of APIA with different P/Al molar ratio; Nitrogen adsorption-desorption isotherm and micro-pore distribution of the aluminophosphate material; Thermogravimetric curves of APIA, pure fibers, and WBB; Comparison of the bonding strength of our work with ever-reported works.



Notes

The authors declare no competing financial interest. ACKNOWLEDGMENT This paper is supported by the Scientific Research Foundation of Graduate School of Fujian Agriculture and Forestry University (1122YB020 and 1122YB033). The authors are also grateful for the financial support of the National Science and Technology Support Program (2008BADA9B01) and the National Natural Science Foundation of China (NSFC) (30781982).

ABBREVIATIONS

APIA, aluminophosphate inorganic adhesive; n(P)/n(Al), P/Al molar ratio; WBB, wood-based boards; SEM-EDS, scanning electron microscopy with an energy-dispersive spectroscopy; XPS, X-ray photoelectron spectroscopy; NMR, nuclear magnetic resonance; FT-IR, Fourier transform infrared spectroscopy; TG, thermogravimetric; DTG, differential thermogravimetric; Al(OH)3, aluminium hydroxide; H3PO4, phosphoric acid. REFERENCES

(1) Ye, R.; Chyan, Y.; Zhang, J.; Li, Y.; Han, X.; Kittrell, C.; Tour, J. M. Laser-induced graphene formation on wood. Adv. Mater. 2017, 29 (37), 1702211, DOI 10.1002/adma.201702211.


Page 22 of 33

Page 23 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(2) Yu, C. W. F.; Kim, J. T. Long-term impact of formaldehyde and VOC emissions from wood-based products on indoor environments; and issues with recycled products. Indoor Built Environ. 2012, 21 (1), 137-149, DOI 10.1177/1420326X11424330.

(3) Costa, N.; Pereira, J.; Martins, J.; Ferra, J.; Cruz, P.; Magalhães, F.; Mendes, A.; Carvalho, L. Alternative to latent catalysts for curing UF resins used in the production of low formaldehyde emission wood-based panels. Int. J. Adhes. Adhes. 2012, 33, 56-60, DOI 10.1016/j.ijadhadh.2011.11.003.

(4) Moubarik, A.; Allal, A.; Pizzi, A.; Charrier, F.; Charrier, B. Preparation and mechanical characterization of particleboard made from maritime pine and glued with bio-adhesives based on cornstarch and tannins. Maderas-Cienc. Tecnol. 2010, 12 (3), 189-197, DOI 10.4067/S0718-221X2010000300004.

(5) Nielsen, G. D.; Larsen, S. T.; Wolkoff, P. Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment. Arch. Toxicol. 2017, 91 (1), 35-61, DOI 10.1007/s00204-016-1733-8.

(6) Dunky, M. Urea-formaldehyde (UF) adhesive resins for wood. Int. J. Adhes. Adhes. 1998, 18 (2), 95-107, DOI 10.1016/S0143-7496(97)00054-7.

(7) Raja, D. S.; Sultana, B. Potential health hazards for students exposed to formaldehyde in the gross anatomy laboratory. J. Environ. Health 2012, 74 (6), 36-40.



(8) Hun, D. E.; Corsi, R. L.; Morandi, M. T.; Siegel, J. A. Formaldehyde in residences: long-term indoor concentrations and influencing factors. Indoor Air 2010, 20 (3), 196-203, DOI 10.1111/j.0905-6947.2010.00644.x.

(9) D’Amico, S.; Hrabalova, M.; Müller, U.; Berghofer, E. Bonding of spruce wood with wheat flour glue-effect of press temperature on the adhesive bond strength. Ind. Crop. Prod. 2010, 31 (2), 255-260, DOI 10.1016/j.indcrop.2009.11.001.

(10) Mansouri, H. R.; Navarrete, P.; Pizzi, A.; Tapin-Lingua, S.; Benjelloun-Mlayah, B.; Pasch, H.; Rigolet, S. Synthetic-resin-free wood panel adhesives from mixed low molecular mass lignin and tannin. Eur. J. Wood Wood Prod. 2011, 69 (2), 221-229, DOI 10.1007/s00107-010-0423-0.

(11) Zhang, Y.; Ding, L.; Gu, J.; Tan, H.; Zhu, L. Preparation and properties of a starch-based wood adhesive with high bonding strength and water resistance. Carbohyd. Polym. 2015, 115, 32-37, DOI 10.1016/j.carbpol.2014.08.063.

(12) Moubarik, A.; Charrier, B.; Allal, A.; Charrier, F.; Pizzi, A. Development and optimization of a new formaldehyde-free cornstarch and tannin wood adhesive. Eur. J. Wood Wood Prod. 2010, 68 (2), 167-177, DOI 10.1007/s00107-009-0357-6.

(13) Qi, G.; Sun, X. S. Soy protein adhesive blends with synthetic latex on wood veneer. J. Am. Oil Chem. Soc. 2011, 88 (2), 271-281, DOI 10.1007/s11746-010-1666-y.


Page 24 of 33

Page 25 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(14) Luo, J.; Gao, Q.; Li, J. Effects of heat treatment on wet shear strength of plywood bonded with soybean meal-based adhesive. Ind. Crop. Prod. 2015, 63, 281-286, DOI 10.1016/j.indcrop.2014.09.054.

(15) Hamarneh, A. I.; Heeres, H. J.; Broekhuis, A. A.; Sjollema, K. A.; Zhang, Y.; Picchioni, F. Use of soy proteins in polyketone-based wood adhesives. Int. J. Adhes. Adhes. 2010, 30 (7), 626-635, DOI 10.1016/j.ijadhadh.2010.06.002.

(16) Kaboorani, A.; Riedl, B. Improving performance of polyvinyl acetate (PVA) as a binder for wood by combination with melamine based adhesives. Int. J. Adhes. Adhes. 2011, 31 (7), 605-611, DOI 10.1016/j.ijadhadh.2011.06.007.

(17) Lin, Q.; Chen, N.; Bian, L.; Fan, M. Development and mechanism characterization of high performance soy-based bio-adhesives. Int. J. Adhes. Adhes. 2012, 34, 11-16, DOI 10.1016/j.ijadhadh.2012.01.005.

(18) Tan, H.; Zhang, Y.; Weng, X. Preparation of the plywood using starch-based adhesives modified with blocked isocyanates. Procedia Eng. 2011, 15, 1171-1175, DOI 10.1016/j.proeng.2011.08.216.

(19) Wagh, A. S.; Jeong, S. Y. Chemically bonded phosphate ceramics: III, reduction mechanism and its application to iron phosphate ceramics. J. Am. Ceram. Soc. 2003, 86(11), 1850-1855, DOI 10.1111/j.1151-2916.2003.tb03571.x.



(20) Hong, L. Y.; Han, H. J.; Ha, H., Lee, J. Y.; Kim, D. P. Development of Cr-free aluminum phosphate binders and their composite applications. Compos. Sci. Technol. 2007, 67(6), 1195-1201, DOI 10.1016/j.compscitech.2006.05.025.

(21) Kingery, W. D. Fundamental study of phosphate bonding in refractories: I, literature review. J. Am. Ceram. Soc. 1950, 33(8), 239-241, DOI 10.1111/j.1151-2916.1950.tb14171.x.

(22) Vippola, M.; Keränen, J.; Zou, X.; Hovmöller, S.; Lepistö, T.; Mäntylä, T. Structural characterization of aluminum phosphate binder. J. Am. Ceram. Soc. 2000, 83 (7), 1834-1836, DOI 10.1111/j.1151-2916.2000.tb01477.x.

(23) Chen, D.; He, L.; Shang, S. Study on aluminum phosphate binder and related Al2O3-SiC ceramic coating. Mat. Sci. Eng. A-Struct. 2003, 348 (1), 29-35, DOI 10.1016/S0921-5093(02)00643-3.

(24) Leivo, E.; Vippola, M. S.; Sorsa, P. P. A.; Vuoristo, P. M. J.; Mäntylä, T. A. Wear and corrosion properties of plasma sprayed Al2O3 and Cr2O3 coatings sealed by aluminum phosphates. J. Therm. Spray Technol. 1997, 6 (2), 205-210, DOI 10.1007/s11666-997-0014-8.

(25) Apanasevich, N.; Sokal, A.; Lapko, K.; Kudlash, A.; Lomonosov, V.; Plyushch, A.; Kuzhir, P.; Macutkevic, J.; Banys, J.; Okotrub, A. Phosphate ceramics-carbon nanotubes composites:liquid aluminum phosphate vs solid magnesium phosphate binder. Ceram. Int. 2015, 41 (9), 12147-12152, DOI 10.1016/j.ceramint.2015.06.033.


Page 26 of 33

Page 27 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(26) Olsbye, U.; Svelle, S.; Bjørgen, M.; Beato, P.; Janssens, T. V. W.; Joensen, F.; Bordiga, S.; Lillerud, K. P. Conversion of methanol to hydrocarbons: how zeolite cavity and pore size controls product selectivity. Angew. Chem. Int. Edit. 2012, 51 (24), 5810-5831, DOI 10.1002/anie.201103657.

(27) Jae, J.; Coolman, R.; Mountziaris, T. J.; Huber, G. W. Catalytic fast pyrolysis of lignocellulosic biomass in a process development unit with continual catalyst addition and removal. Chem. Eng. Sci. 2014, 108, 33-46, DOI 10.1016/j.ces.2013.12.023.

(28) Xiang, Y.; Xin, L.; Deetz, J. D.; Sun, H. Reaction mechanisms of the initial oligomerization of aluminophosphate. J. Phys. Chem. A 2016, 120 (18), 2902-2910, DOI 10.1021/acs.jpca.6b01058.

(29) Xu, R.; Zhang, W.; Xu, J.; Tian, Z.; Deng, F.; Han, X.; Bao, X. Multinuclear solid-state NMR studies on the formation mechanism of aluminophosphate molecular sieves in ionic liquids. J. Phys. Chem. C 2013, 117 (11), 5848-5854, DOI 10.1021/jp400422z.

(30) Yang, W. Y.; Qian, J. W.; Shen, Z. Q. A novel flocculant of Al(OH)3-polyacrylamide ionic hybrid. J. Colloid Interface Sci. 2004, 273 (2), 400-405, DOI 10.1016/j.jcis.2004.02.002.

(31) ElOkr, M. M.; Metawe, F.; El-Nahrawy, A. M.; Osman, B. A. Enhanced structural and spectroscopic properties of phosphosilicate nanostructures by doping with Al2O3 ions and calcinations temperature. Int. J. ChemTech Res. 2016, 9 (5), 228-234.



(32) Liu, H. S.; Chin, T. S.; Yung, S. W. FTIR and XPS studies of low-melting PbO-ZnO-P2O2 glasses. Mater. Chem. Phys. 1997, 50 (1), 1-10, DOI 10.1016/S0254-0584(97)80175-7.

(33) Dobbelaere, T.; Roy, A. K.; Vereecken, P.; Detavernier, C. Atomic layer deposition of aluminum phosphate based on the plasma polymerization of trimethyl phosphate. Chem. Mater. 2014, 26 (23), 6863-6871, DOI 10.1021/cm503587w.

(34) Chakraborty, S.; Paul, A. Relative role of Al2O3 and PbO in binary and ternary phosphate glasses. J. Mater. Sci. Lett. 1989, 8 (11), 1358-1359, DOI 10.1007/BF00721521.

(35) Bagnold, R. A. Experiments on a gravity-free dispersion of large solid spheres in a Newtonian fluid under shear. P. Roy. Soc. Lond. A Mat. 1954, 225 (1160), 49-63, DOI 10.1098/rspa.1954.0186.

(36) Liu, W.; Xie, T.; Qiu, R. Biobased thermosets prepared from rigid isosorbide and flexible soybean oil derivatives. ACS Sustain. Chem. Eng. 2017, 5 (1), 774-783, DOI 10.1021/acssuschemeng.6b02117.

(37) Peskov, M. V.; Blatov, V. A.; Ilyushin, G. D.; Schwingenschlögl, U. Computer-aided modeling of aluminophosphate zeolites as packings of building units. J. Phys. Chem. C 2012, 116 (11), 6734-6744, DOI 10.1021/jp2115252.

(38) Liu, Z.; Song, X.; Li, J.; Li, Y.; Yu, J.; Xu, R. I(C4NH12)4|[M4Al12P16O64] (M = Co, Zn): new heteroatom-containing aluminophosphate molecular sieves with two intersecting 8-ring channels. Inorg. Chem. 2012, 51 (3), 1969-1974, DOI 10.1021/ic2022903.


Page 28 of 33

Page 29 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(39) Chyba, J.; Moravec, Z.; Necas, M.; Mathur, S.; Pinkas, J. Construction of larger molecular aluminophosphate cages from the cyclic four-ring building unit. Inorg. Chem. 2014, 53 (7), 3753-3762, DOI 10.1021/ic500083a.

(40) Page, M. G.; Warr, G. G. Structure and dynamics of self-assembling aluminum didodecyl phosphate organogels. J. Phys. Chem. B 2004, 108 (43), 16983-16989, DOI 10.1021/jp0470602.

(41) Liu, W.; Chen, T.; Xie, T.; Qiu, R. Soybean oil-based thermosets with N-vinyl-2-pyrrolidone as crosslinking agent for hemp fiber composites. Compos. Part A-Appl. S. 2016, 82, 1-7, DOI 10.1016/j.compositesa.2015.11.035.

(42) La Scala, J. J.; Sands, J. M.; Orlicki, J. A.; Robinette, E. J.; Palmese, G. R. Fatty acid-based monomers as styrene replacements for liquid molding resins. Polymer 2004, 45 (22), 7729-7737, DOI 10.1016/j.polymer.2004.08.056.

(43) Xia, W.; Yang, J.; Liang, C. Investigation of changes in surface properties of bituminous coal during natural weathering processes by XPS and SEM. Appl. Surf. Sci. 2014, 293, 293-298, DOI 10.1016/j.apsusc.2013.12.151.

(44) Hao, S.; Wen, J.; Yu, X.; Chu, W. Effect of the surface oxygen groups on methane adsorption on coals. Appl. Surf. Sci. 2013, 264, 433-442, DOI 10.1016/j.apsusc.2012.10.040.

(45) Chen, Z. L.; Fu, F.; Ye, K. L.; Wang, Q.; Zuo, T. Y. Preparation of the SiO2 gel/wood composites from TEOS sol with hydrolyzing. J. Beijing Univ. Technol. 2010, 36 (2), 250-253.



(46) Jian, Q.; Jian, L. Preparation of wood-silica aerogels composites by supercritical drying technique and its nano-structure. J. Northeast For. Univ. 2005, 33 (3), 3-4.

(47) Reddy, K. M.; Song, C. S. Synthesis of mesoporous molecular sieves: influence of aluminum source on Al incorporation in MCM-41. Catal. Lett. 1996, 36(1-2), 103-109, DOI 10.1007/BF00807213.

(48) Chiranjeevi, T.; Muthu Kumaran, G.; Gupta, J. K.; Murali Dhar, G. Synthesis and characterization of acidic properties of Al-HMS materials of varying Si/Al ratios. Thermochim. Acta 2006, 443(1), 87-92, DOI 10.1016/j.tca.2006.01.004.

(49) Van Der Bij, H. E.; Cicmil, D.; Wang. J.; Meirer, F.; De Groot, F. M.; Weckhuysen, B. M. Aluminum-phosphate binder formation in zeolites as probed with X-ray absorption microscopy. J. Am. Chem. Soc. 2014, 136(51), 17774-17787, DOI 10.1021/ja508545m.

(50) Huang, Y.; Demko, B. A.; Kirby, C. W. Investigation of the evolution of intermediate phases of AlPO4-18 molecular sieve synthesis. Chem. Mater. 2003, 15(12), 2437-2444, DOI 10.1021/cm021728c.

(51) Sears, D. N.; Demko, B. A.; Ooms, K. J.; Wasylishen, R. E.; Huang, Y. Formation of porous aluminophosphate frameworks monitored by hyperpolarized 129Xe NMR spectroscopy. Chem. Mater. 2005, 17(22), 5481-5488, DOI 10.1021/cm0513132.

(52) Sayari, A.; Moudrakovski, I.; Reddy, J. S.; Ratcliffe, C. I.; Ripmeester, J. A.; Preston, K. F. Synthesis of mesostructured lamellar aluminophosphates using supramolecular templates. Chem. Mater. 1996, 8(8), 2080-2088, DOI 10.1021/cm960029v.


Page 30 of 33

Page 31 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(53) Mortlock, R. F.; Bell, A. T.; Radke, C. J. Phosphorus-31 and aluminum-27 NMR investigations of the effects of pH on aqueous solutions containing aluminum and phosphorus. J. Phys. Chem. 1993, 97(3), 775-782, DOI 10.1021/j100105a040

(54) Shen, D.; Xiao, R.; Gu, S.; Zhang, H. The Overview of Thermal Decomposition of Cellulose in Lignocellulosic Biomass. In Cellulose - Biomass Conversion; Ven, T. V. D.; Kadla, J., Eds. InTech: Rijeka, Croatia, 2013, DOI 10.5772/51883.

(55) Vilcu, R.; Olteanu, M.; Mândru, I. Thermal behaviour of some mixture of collagen hydrolysates with vinylic polymers. Eur. Polym. J. 1985, 21 (1), 81-83, DOI 10.1016/0014-3057(85)90069-2.

(56) Unuabonah, E. I.; Günter, C.; Weber, J.; Lubahn, S.; Taubert, A. Hybrid clay: A new highly efficient adsorbent for water treatment. ACS Sustain. Chem. Eng. 2013, 1 (8), 966-973, DOI 10.1021/sc400051y.

(57) Wada, M.; Heux, L.; Sugiyama, J. Polymorphism of cellulose I family: reinvestigation of cellulose IVI. Biomacromolecules 2004, 5(4), 1385-1391, DOI 10.1021/bm0345357.

(58) Zahedi-Niaki, M. H., Zaidi, S. J., Kaliaguine, S. Comparative study of vanadium aluminophosphate molecular sieves VAPO-5,-11,-17 and-31. Appl. Catal. A-Gen. 2000, 196(1), 9-24, DOI 10.1016/S0926-860X(99)00459-7.

(59) Zhong, S., Song, S., Wang, B., Bu, N., Ding, X., Zhou, R., Jin, W. Fast preparation of ERI-structure AlPO-17 and SAPO-17 in the presences of isomorphous and heterogeneous seeds. Micropor. Mesopor. Mater. 2017, 263, 11-20, DOI 10.1016/j.micromeso.2017.11.034.



(60) Chen, T.; Xie, Y.; Cai, L.; Zhuang, B.; Wang, X. A.; Wu, Z.; Niu, M.; Lin, M. Mesoporous aluminosilicate material with hierarchical porosity for ultra-low density wood fiber composite (ULD_WFC). ACS Sustain. Chem. Eng. 2016, 4 (7), 3888-3896, DOI 10.1021/acssuschemeng.6b00691.

(61) GB/T 9846-2015. In Plywood for general use, Standardization Administration of China: Beijing, China, 2015.

(62) Shin, Y. S.; Liu, J.; Chang, J. H.; Nie, Z. M.; Exarhos, G. J. Hierarchically Ordered Ceramics Through Surfactant-Templated Sol-Gel Mineralization of Biological Cellular Structures. Adv. Mater. 2001, 13(10), 728-732, DOI 10.1002/1521-4095(200105)13:103.0.CO;2-J.

(63) Sieber, H.; Hoffmann, C.; Kaindl, A.; Greil, P. Biomorphic cellular ceramics. Adv. Engineer. Mater. 2000, 2(3), 105-109, DOI 10.1002/(SICI)1527-2648(200003)2:33.0.CO;2-P.


Page 32 of 33

Page 33 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


For Table of Contents Use Only

TOC graph:

Synopsis: Mechanical properties of sustainable wood-based boards were improved by hierarchical lamellar aluminophosphate materials with porosity as eco-friendly inorganic adhesive.


Hierarchical Lamellar Aluminophosphate Materials with Porosity as

Recommend Documents