多胺基聚合物改性室温固化型MUF树脂胶黏剂

为解决三聚氰胺-尿素-甲醛(MUF)树脂作为室外级结构集成材胶黏剂时存在的脆性大、易开裂的问题,得到韧性优秀且综合性能满足室外级结构集成材标准的室温固化型MUF树脂胶黏剂,本研究在MUF树脂合成中使用两种改性剂尿素-乙二胺(UE)、尿素-三(2-氨基乙基)胺(UD)分别替代部分三聚氰胺合成了 MUF-UE、MUF-UD...

Polyamine-based polymer modified room temperature curing MUF adhesive

As a structural adhesive,melamine-urea-formaldehyde(MUF)resin can be cured at high temperatures or at room temperatures.Being used as room temperature curing adhesive,MUF resin has unique advantages such as reasonable price and moderate viscosity.However,the MUF resin also has problems that cannot be ignored,such as brittleness and stress cracking.This article modified the room temperature curing MUF adhesive using long-chain polyamine-based polymer urea-ethylenediamine(UE)and hyperbranched polyamine-based polymer urea-tris(2-aminoethyl)amine(UD).These two polymers contain active amino groups,which can participate in the polymerization reaction of the MUF resin,so as to achieve the purpose of strengthening the resin structure and improving the mechanical properties of the resin.The results showed that,compared with the MUF resin,the tensile strength and elongation at break of the modified MUF-UE resin increased by 51.5%and 30.8%,respectively.The shear strength of the MUF-UE glulam is 8.00 MPa,and the peeling rate of the second cycle of cold boiling water is 0%,which meets the requirements of the Chinese national standard for outdoor-level structural laminated timber,so MUF-UE resin can be used for outdoor-level structural integration wood adhesives.However,the tensile strength and shear strength of MUF-UD glulam did not increase significantly.The tensile strength of MUF-UE resin decreased by 9.4%,and the elongation at break increased by 10.8%.Compared with the MUF resin,the cold or boiling water peeling rate of the MUF-UD glulam is 0%,but the increase in shear strength is not obvious.Obviously,the effect of UD as a modifier is poor.Structural analysis of ESI-MS and FT-IR showed that the amino groups in UE and UD can participate in the synthesis of the MUF resin and form polycondensation products without changing the structure of the main functional groups in the resin system.According to the thermal analysis,the addition of the modifier UE can increase the performance of the resin,and the degree of resin curing is improved.This may be due to the introduction of long-chain polymers,which significantly increases the compactness of the resin through interpenetration degree,thereby enhancing mechanical properties.