Tough Structural Adhesives with Ultra-Resistance to Both High and Cryogenic Temperature

Abstract

Structural adhesion at high temperature has been a challenge for organic adhesives, and the commercially available adhesives that can work at a temperature above 150 °C is rather limited. Herein, two novel polymers were designed and synthesized via facile strategy, which involves polymerization between melamine (M) and M–Xylylenediamine (X), as well as copolymerization of MX and urea (U). With well-balanced rigid-flexible structures, the obtained MX and MXU resins were proved to be outstanding structural adhesives at a wide range temperature of −196~200 °C. They provided room-temperature bonding strength of 13~27 MPa for various substrates, steel bonding strength of 17~18 MPa at cryogenic temperature (−196 °C), and 15~17 MPa at 150 °C. Remarkably, high bonding strength of 10~11 MPa was retained even at 200 °C. Such superior performances were attributed to a high content of aromatic units, which leads to high glass transition temperature (Tg) up to ~179 °C, as well as the structural flexibility endowed by the dispersed rotatable methylene linkages.

Ultralow-Temperature-Tolerance Adhesive with Excellent Toughness and Record-High Strength

“…Therefore, the debonding energy increases from 5.34 ± 3.21 kN/m (HTA 0 ) to 61.16 ± 10.69 kN/m (HTA 0.5 ), 46.47 ± 7.22 kN/m (HTA 1 ), and 61.91 ± 20.12 kN/m (HTA 2 ), respectively, with an increase of 1045%, 770% and 1059%, respectively (Figure c). To the best of the authors’ knowledge, the lap-shear strength and the debonding work are 5 times higher than those reported in literatures ,− (Figure d), which is due to the relatively lower cross-sectional point of HTA 0.5 in the rheological modulus plot compared to HTA 1 . Taking HTA 0.5 as an example, it was further investigated at various temperatures and bonded to different substrates.…”

Epoxidized Soybean-Oils-Based Pressure-Sensitive Adhesives with Di-Hydroxylated Soybean-Oils Copolymerizing and Antioxidant Grafting

“…Bio-based PSAs, especially vegetable-oils-based PSAs, have been considered to be a promising potential alternative to petroleum-based PSAs, which are mainly derived from acrylics, silicones, ethylene vinyl acetates, polyurethanes, polyisoprenes, polybutadienes, etc. [ 3 , 4 ]. Vegetable oils are mainly triglycerides in which glycerol is esterified with three saturated or unsaturated fatty acids.…”

Assessment of Durability and Aging Resilience in a Novel Structural Building Adhesive: An Examination of the Time-Temperature Equivalence Principle

“…Over several decades, extensive studies have confirmed that the creep and stress relaxation curves of a material during extended mechanical testing exhibit similar shapes at different time points throughout the physical aging process of polymers [5,6]. These curves can be transposed along the time axis under varying circumstances to construct a master curve at a specific time point, thereby accelerating the process of characterizing the mechanical properties of materials [5,6]. Through examining relaxation phenomena in molecular chain segments, it has been observed that mechanical relaxation can occur at both high temperatures over short periods and low temperatures over extended durations.…”