Development of new natural polymer-based wood adhesives I: dry bond strength and water resistance of konjac glucomannan, chitosan, and their composites

2003 ◽  
Vol 49 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Kenji Umemura ◽  
Akio Inoue ◽  
Shuichi Kawai
Keyword(s):  
Bond Strength ◽  
Water Resistance ◽  
Konjac Glucomannan ◽  
Natural Polymer ◽  
Wood Adhesives

scholarly journals Dry Bond Strength and Water Resistance of Konjac Glucomannan, Chitosan, and Polyvinyl Alcohol Blend Adhesive

BioResources ◽  
2015 ◽  
Vol 10 (4) ◽  
Author(s):  
Xianqing Chen ◽  
Nan Xia ◽  
Kangquan Guo ◽  
Chusheng Qi
Keyword(s):  
Polyvinyl Alcohol ◽  
Bond Strength ◽  
Water Resistance ◽  
Konjac Glucomannan

scholarly journals Chitosan-Based Adhesive: Optimization of Tensile Shear Strength in Dry and Wet Conditions

2021 ◽  
Vol 2 (1) ◽  
pp. 110-120
Author(s):  
Maisa Abdelmoula ◽  
Hajer Ben Hlima ◽  
Frédéric Michalet ◽  
Gérard Bourduche ◽  
Jean-Yves Chavant ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Shear Strength ◽  
Bond Strength ◽  
Water Resistance ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Spread Rate ◽  
Assembly Time ◽  
Deacetylation Degree ◽  
Dry And Wet Conditions

Commercial adhesives present a high bond strength and water resistance, but they are considered non-healthier products. Chitosan can be considered as an interesting biosourced and biodegradable alternative, despite its low water resistance. Here, its wood bonding implementation and its tensile shear strength in dry and wet conditions were investigated depending on its structural characteristics. Firstly, the spread rate, open assembly time, drying pressure, drying temperature, and drying time have been determined for two chitosans of European pine double lap specimens. An adhesive solution spread rate of 1000 g·m−2, an open assembly time of 10 min, and a pressure temperature of 55 °C for 105 min led to a bond strength of 2.82 MPa. Secondly, a comparison between a high molecular weight/low deacetylation degree chitosan and a lower molecular weight/higher deacetylation degree chitosan was conducted. Tests were conducted with beech simple lap specimens in accordance with the implementation conditions and the conditioning treatments in wet and dry environments required for thermoplastic wood adhesive standards used in non-structural applications (EN 204 and EN 205). The results clearly revealed the dependence of adhesive properties and water resistance on the structural features of chitosans (molecular weight and deacetylation degree), explaining the heterogeneity of results published notably in this field.

scholarly journals Peanut meal-based wood adhesives enhanced by urea and epichlorohydrin

2019 ◽  
Vol 6 (11) ◽  
pp. 191154 ◽  
Author(s):  
Chen Chen ◽  
Fusheng Chen ◽  
Boye Liu ◽  
Yan Du ◽  
Chen Liu ◽  
...  
Keyword(s):  
High Performance ◽  
Water Resistance ◽  
Rapid Development ◽  
Peanut Meal ◽  
Decomposition Temperature ◽  
Solid Content ◽  
Added Value ◽  
Wood Adhesives ◽  
Plywood Industry ◽  
Reactive Groups

Peanut meal (PM) has recently emerged as a potential protein source for wood adhesives, owing to superior features such as high availability, renewability and eco-friendliness. However, the poor properties of unmodified PM-based wood adhesives, compared with their petroleum-derived counterparts, limit their use in high-performance applications. In order to promote the application of PM-based wood adhesives in plywood industry, urea (U) and epichlorohydrin (ECH) were used to enhance the properties of the adhesives and the modification mechanism was investigated. PM-based wood adhesives made with U and ECH were shown to possess sufficient water resistance and exhibited higher apparent viscosity and solid content than without. Fourier-transform infrared spectroscopy results suggested that U denatured PM protein and expose more reactive groups, allowing ECH to react better with U-treated PM protein to form a dense, cross-linked network which was the main reason for the improvement of the properties. The crystallinity increased from 2.7% to 11% compared with the control, indicating that the molecular structure of the resultant adhesive modified by U and ECH became more regular and compact owing to the cross-linked network structure. Thermogravimetry tests showed that decomposition temperature of the protein skeleton structure increased from 307°C to 314°C after U and ECH modification. Scanning electron microscopy images revealed that using U and ECH for adhesives resulted in a smooth protein surface which prevented moisture penetration and improved water resistance. PM-based adhesives thus represent potential candidates to replace petroleum-derived adhesives in the plywood industry, which will effectively promote the rapid development of eco-friendly adhesives and increase the added value of PM.

Development and evaluation of new curing agents derived from glycerol for formaldehyde-free soy-based adhesives in wood composites

Holzforschung ◽  
2013 ◽  
Vol 67 (6) ◽  
pp. 659-665 ◽  
Author(s):  
Jian Huang ◽  
Kai Gu ◽  
Kaichang Li
Keyword(s):  
Bond Strength ◽  
Modulus Of Elasticity ◽  
Internal Bond ◽  
Water Resistance ◽  
Ammonium Hydroxide ◽  
Soy Flour ◽  
Modulus Of Rupture ◽  
Wood Composites ◽  
Curing Agents ◽  
Resistance Tests

Abstract Three novel curing agents (I, II, and III) were synthesized from epichlorohydrin and ammonium hydroxide. The combinations of soy flour (SF) with one of the curing agents (SF-I, SF-II, and SF-III) were investigated as adhesives for making interior plywood. Water resistance tests showed that plywood panels bonded with SF-I and SF-III adhesives met the requirements of interior plywood, whereas those bonded with SF-II did not. The modulus of rupture, modulus of elasticity, and internal bond strength of particleboard panels bonded with the SF-II adhesive all exceeded the corresponding minimum industrial requirements for M-2 grade particleboard.

scholarly journals Assessing wood adhesives used in conservation by testing their bond strength and ageing behavior

2018 ◽  
Vol 10 ◽  
pp. 227-234 ◽  
Author(s):  
E. Tsetsekou ◽  
A. Platanianaki ◽  
A. Pournou
Keyword(s):  
Bond Strength ◽  
Wood Adhesives

scholarly journals Development of a High-Performance Adhesive with a Microphase, Separation Crosslinking Structure Using Wheat Flour and a Hydroxymethyl Melamine Prepolymer

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 893 ◽  
Author(s):  
Jieyu Zhang ◽  
Yi Zhang ◽  
Jianzhang Li ◽  
Qiang Gao
Keyword(s):  
Shear Strength ◽  
Fracture Surface ◽  
Bond Strength ◽  
Wheat Flour ◽  
High Performance ◽  
Water Resistance ◽  
Microphase Separation ◽  
Low Cost ◽  
Bond Performance ◽  
Effective Manner

The objective of this study is to use wheat flour (WF) and hydroxymethyl melamine prepolymer (HMP) to develop a low cost, highly water-resistant, starch-based bio-adhesive for plywood fabrication. Three-layer plywood was fabricated using the resultant adhesive, and the wet shear strength of the plywood samples was measured under various conditions. After determining that water resistance was significantly improved with the addition of HMP, we evaluated the physical characteristics of the starch-based adhesive and functional groups and analyzed the thermal stability and fracture surface of the cured adhesive samples. Results showed that by adding 20 wt.% HMP into WF adhesive, the sedimentation volume in the resultant adhesive decreased by 11.3%, indicating that the increase of crosslinking in the structure of the adhesives increased the bond strength, and the wet shear strength of the resultant plywood in 63 °C water improved by 375% when compared with the WF adhesive. After increasing the addition of HMP to 40 wt.%, the wet shear strength of the resultant plywood in 100 °C water changed from 0 MPa to 0.71 MPa, which meets the exterior use plywood requirement. This water resistance and bond strength improvement resulted from (1) HMP reacting with functions in WF and forming a crosslinking structure to prevent moisture intrusion; and (2) HMP self-crosslinking and combining with crosslinked WF to form a microphase separation crosslinking structure, which improved both the crosslinking density and the toughness of the adhesive, and subsequently, the adhesive’s bond performance. In addition, the microphase separation crosslinking structure had better thermostability and created a compact ductile fracture surface, which further improved the bond performance of the adhesive. Thus, using a prepolymer to form a microphase separation crosslinking structure within the adhesive improves the rigidity, toughness, and water resistance of the material in a practical and cost-effective manner.

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