Chem. J. Chinese Universities ›› 2021, Vol. 42 ›› Issue (8): 2651.doi: 10.7503/cjcu20200824

• Polymer Chemistry • Previous Articles     Next Articles

Preparation and Performance Analysis of Extremely High Strength Self-repairing Waterborne Polyurethane Adhesive Based on Oxime-carbamate

LI Cong, LIU Huanhuan, YANG Guihua(), TIAN Zhongjian, YAN Jiaqiang, JI Xingxiang, HAN Wenjia, CHEN Jiachuan()   

  1. State Key Laboratory of Biobased Materials and Green Papermaking Co?founded by Shandong and the Ministry of Science and Technology/Key Laboratory of Pulp & Paper Science and Technology of Education Ministry,Qilu University of Technology (Shandong Academy of Sciences),Jinan 250353,China
  • Received:2020-11-20 Online:2021-08-10 Published:2021-08-05
  • Contact: YANG Guihua E-mail:ygh@qlu.edu.cn;chenjc@qlu.edu.cn

Abstract:

From the perspective of recycling, commercial polyurethane hot-melt adhesives (HMA) could be reused many times via hot melting. However, the performance degradation after recylcing seriously impaired the reuse value. Although thermosetting structures could improve the performance, the material would not be reused once it was cured in view of the above challenges. A new water-based emulsion with high strength and dynamic network structure was synthesized from dimethylglyoxime, which was based on the thermal reversible bonding of carbamate ester, a commercially available chemical as the building block. In this paper, the rever-sible bonding characteristics of oxime-carbamate were analyzed by variable temperature infrared spectroscopy and differential scanning calorimetry. The dynamic dissociation phenomenon of the network at high temperature was strongly verified. The corresponding network relaxation behavior was quantitatively studied by dynamic mechanical spectrometer. The results showed that the proper hard segment content and structural design would give the adhesive the extremely high bonding strength (25 MPa, the commercially available hot-melt adhesive <6 MPa), excellent emulsion stability (particle size <100 nm), and the repair efficiency closed to 97% (lap shear test at 160 ℃ for 10 min). These waterborne emulsions had the characteristics of high strength, self repair and expandability, which opened up a feasible way for commercial application of this functional material in the field of adhesives.

Key words: Waterborne polyurethane, Adhesive strength, Dimethylglyoxime, Self-repairing

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