摘要
涂层在长期使用过程中容易受到损伤而产生微小裂纹,暴露在空气、水分和盐分等介质中会加速微裂纹的扩散,使得涂料的防护性能和美观性能显著下降,而具备自修复能力的涂层能够延长涂层的使用寿命。首先以二乙醇胺(DEA)和四羟甲基苯硼酸(HPBA)为原料制备一端氨基一端羟基的含氮硼内配位的硼酸酯键化合物(NCBC),并将NCBC与二苯基甲烷二异氰酸酯(MDI)反应制备了两端羟基封端的含硼酸酯键化合物(MN);然后以聚四氢呋喃(PTMEG-1000)和MDI为原料,MN为扩链剂制备了自修复聚氨酯(PU)及其涂料。元素分析、核磁共振氢谱和傅里叶变换红外光谱分析证明成功制备了NCBC和MN化合物,NCBC具有较好的耐水性能。试验结果表明:聚氨酯引入MN(n(MDI)∶n(NCBC)=1∶2.0)扩链剂,自修复PU的拉伸强度为6.06 MPa,修复后拉伸强度为5.47 MPa,自修复效率为90.2%。木材表面聚氨酯漆膜的铅笔硬度高达3H,附着力为0级,耐冲击性大于50 cm,柔韧性为2 mm,表面划痕在60℃条件下修复12 h后完全愈合,表明自修复聚氨酯漆膜具备良好的自愈合性能。
Polyurethane(PU)is a common polymer material,which is a multiblock copolymer prepared by the addition reaction of organic isocyanates and polymer polyols.Its performance is between plastic and rubber,with characteristics of high hardness,good elasticity,oil resistance,wear resistance,low temperature resistance,and aging resistance.It is widely used in the fields of construction,automotive,aviation,insulation,footwear industries,and home furnishings,and also used as raw materials for making adhesives and coatings.Polyurethane coatings have the advantages of strong adhesion,wear resistance,scratch resistance,good glossiness,and high decorative performance,playing an important role in wood and automobile industries.However,PU coatings are prone to damage and produce microcracks during long-term service.When microcracks are exposed to corrosive media such as air,water,and salt,the diffusion of microcracks is accelerated,significantly reducing the protective and aesthetic properties of coatings.Self-healing coatings can extend the service life.In this study,firstly,diethanolamine(DEA)and 4-methyl phenylboronic acid(HPBA)were used to prepare borate ester bond compound with hydroxyl and amino terminated groups(NCBC).Boric acid ester bond compounds with hydroxyl terminated at both ends(MN)were subsequently prepared via the reaction between NCBC and 4,4-diphenylmethane diisocyanate(MDI).Then,self-healing polyurethane(PU)and its coatings were prepared with polytetrahydrofuran(PTMEG-1000),using MDI as raw materials and MN as chain extender.The elemental analysis,1H nuclear magnetic resonance and Fourier transform infrared spectroscopy structural analysis proved that NCBC and MN compounds were successfully prepared,and NCBC had good water resistance.The results showed that the introduction of MN(n(MDI)∶n(NCBC)=1∶2.0)into polyurethane provide wood coatings with high strength and good self-healing properties.The tensile strength of self-healing PU was 6.06 MPa,and the tensile strength after repairing was 5.47 MPa,with the self-healing efficiency was 90.2%.The pencil hardness of polyurethane coating on the surface of wood can reach up to 3H,the adhesion level was Lever 0,the impact resistance was greater than 50 cm,and the flexibility of film was 2 mm.The scratches on the film surface were completely healed after being repaired at 60℃for 12 h,indicating that the self-healing polyurethane coating has good self-healing performance.
作者
许睿
王鼎
窦柳皓
崔举庆
何磊
冯富奇
刘方方
XU Rui;WANG Ding;DOU Liuhao;CUI Juqing;HE Lei;FENG Fuqi;LIU Fangfang(College of Materials Science and Engineering,Nanjing Forestry University,Nanjing 210037,China)
出处
《林业工程学报》
CSCD
北大核心
2024年第3期54-60,共7页
Journal of Forestry Engineering
基金
国家自然科学基金(31470590)。
关键词
自修复
聚氨酯涂料
硼酸酯键
力学性能
self-healing
polyurethane coating
borate ester bond
mechanical property
作者简介
许睿,男,研究方向为聚合物材料与加工;通信作者:崔举庆,男,教授。E-mail:cuijq@njfu.edu.cn。
